Release v1.0.0 (#361)

Changes:
- Unified error types (`PoseidonError`, `HashError`, etc.) across
hashing, keygen, witness calculation, and serialization for consistent
and descriptive error handling.
- Refactored tests and examples to use `unwrap()` where safe, and
limited `expect()` in library code to non-panicking cases with clear
messaging.
- Improved witness and proof generation by removing panicking code paths
and enforcing proper error propagation.
- Cleaned up outdated imports, removed unused operations in `graph.rs`,
and updated public API documentation.
- Updated C, Nim, and WASM FFI bindings with more robust serialization
and clearer error log messages.
- Added keywords to package.json and update dependencies in
Makefile.toml and Nightly CI.

.github/workflows/ci.yml

@@ -10,6 +10,7 @@ on:
       - "!rln/resources/**"
       - "!utils/src/**"
   pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
     paths-ignore:
       - "**.md"
       - "!.github/workflows/*.yml"
@@ -18,58 +19,54 @@ on:
       - "!rln/resources/**"
       - "!utils/src/**"
 
-name: Tests
+name: CI
 
 jobs:
   utils-test:
+    # skip tests on draft PRs
+    if: github.event_name == 'push' || (github.event_name == 'pull_request' && !github.event.pull_request.draft)
     strategy:
       matrix:
-        platform: [ ubuntu-latest, macos-latest ]
-        crate: [ utils ]
+        platform: [ubuntu-latest, macos-latest]
+        crate: [utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: test - ${{ matrix.crate }} - ${{ matrix.platform }}
+    name: Test - ${{ matrix.crate }} - ${{ matrix.platform }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
+        uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@v2
       - name: Install dependencies
         run: make installdeps
-      - name: cargo-make test
+      - name: Test utils
         run: |
           cargo make test --release
         working-directory: ${{ matrix.crate }}
 
   rln-test:
+    # skip tests on draft PRs
+    if: github.event_name == 'push' || (github.event_name == 'pull_request' && !github.event.pull_request.draft)
     strategy:
       matrix:
-        platform: [ ubuntu-latest, macos-latest ]
-        crate: [ rln ]
-        feature: [ "default", "arkzkey", "stateless" ]
+        platform: [ubuntu-latest, macos-latest]
+        crate: [rln]
+        feature: ["default", "stateless"]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
+    name: Test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
+        uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@v2
       - name: Install dependencies
         run: make installdeps
-      - name: cargo-make test
+      - name: Test rln
         run: |
           if [ ${{ matrix.feature }} == default ]; then
             cargo make test --release
@@ -78,91 +75,123 @@ jobs:
           fi
         working-directory: ${{ matrix.crate }}
 
-  rln-wasm:
+  rln-wasm-test:
+    # skip tests on draft PRs
+    if: github.event_name == 'push' || (github.event_name == 'pull_request' && !github.event.pull_request.draft)
     strategy:
       matrix:
-        platform: [ ubuntu-latest, macos-latest ]
-        feature: [ "default", "arkzkey" ]
+        platform: [ubuntu-latest, macos-latest]
+        crate: [rln-wasm]
+        feature: ["default"]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: test - rln-wasm - ${{ matrix.platform }} - ${{ matrix.feature }}
+    name: Test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
+        uses: dtolnay/rust-toolchain@stable
       - uses: Swatinem/rust-cache@v2
-      - name: Install Dependencies
+      - name: Install dependencies
         run: make installdeps
-      - name: cargo-make build
-        run: |
-          if [ ${{ matrix.feature }} == default ]; then
-            cargo make build
-          else
-            cargo make build_${{ matrix.feature }}
-          fi
-        working-directory: rln-wasm
-      - name: cargo-make test
-        run: |
-          if [ ${{ matrix.feature }} == default ]; then
-            cargo make test --release
-          else
-            cargo make test_${{ matrix.feature }} --release
-          fi
-        working-directory: rln-wasm
+      - name: Build rln-wasm
+        run: cargo make build
+        working-directory: ${{ matrix.crate }}
+      - name: Test rln-wasm on node
+        run: cargo make test --release
+        working-directory: ${{ matrix.crate }}
+      - name: Test rln-wasm on browser
+        run: cargo make test_browser --release
+        working-directory: ${{ matrix.crate }}
+
+  rln-wasm-parallel-test:
+    # skip tests on draft PRs
+    if: github.event_name == 'push' || (github.event_name == 'pull_request' && !github.event.pull_request.draft)
+    strategy:
+      matrix:
+        platform: [ubuntu-latest, macos-latest]
+        crate: [rln-wasm]
+        feature: ["parallel"]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: Test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install nightly toolchain
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          components: rust-src
+          targets: wasm32-unknown-unknown
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - name: Build rln-wasm in parallel mode
+        run: cargo make build_parallel
+        working-directory: ${{ matrix.crate }}
+      - name: Test rln-wasm in parallel mode on browser
+        run: cargo make test_parallel --release
+        working-directory: ${{ matrix.crate }}
 
   lint:
+    # run on both ready and draft PRs
+    if: github.event_name == 'push' || (github.event_name == 'pull_request' && !github.event.pull_request.draft)
     strategy:
       matrix:
-        # we run lint tests only on ubuntu
-        platform: [ ubuntu-latest ]
-        crate: [ rln, rln-wasm, utils ]
+        # run lint tests only on ubuntu
+        platform: [ubuntu-latest]
+        crate: [rln, rln-wasm, utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: lint - ${{ matrix.crate }} - ${{ matrix.platform }}
+    name: Lint - ${{ matrix.crate }} - ${{ matrix.platform }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
-          toolchain: stable
-          override: true
           components: rustfmt, clippy
+      - name: Install wasm32 target
+        if: matrix.crate == 'rln-wasm'
+        run: rustup target add wasm32-unknown-unknown
       - uses: Swatinem/rust-cache@v2
-      - name: Install Dependencies
+      - name: Install dependencies
         run: make installdeps
-      - name: cargo fmt
+      - name: Check formatting
         if: success() || failure()
         run: cargo fmt -- --check
         working-directory: ${{ matrix.crate }}
-      - name: cargo clippy
-        if: success() || failure()
+      - name: Check clippy wasm target
+        if: (success() || failure()) && (matrix.crate == 'rln-wasm')
         run: |
-          cargo clippy --release
+          cargo clippy --target wasm32-unknown-unknown --tests --release -- -D warnings
+        working-directory: ${{ matrix.crate }}
+      - name: Check clippy default feature
+        if: (success() || failure()) && (matrix.crate != 'rln-wasm')
+        run: |
+          cargo clippy --all-targets --tests --release -- -D warnings
+      - name: Check clippy stateless feature
+        if: (success() || failure()) && (matrix.crate == 'rln')
+        run: |
+          cargo clippy --all-targets --tests --release --features=stateless --no-default-features -- -D warnings
         working-directory: ${{ matrix.crate }}
 
   benchmark-utils:
-    # run only in pull requests
-    if: github.event_name == 'pull_request'
+    # run only on ready PRs
+    if: github.event_name == 'pull_request' && !github.event.pull_request.draft
     strategy:
       matrix:
-        # we run benchmark tests only on ubuntu
-        platform: [ ubuntu-latest ]
-        crate: [ utils ]
+        # run benchmark tests only on ubuntu
+        platform: [ubuntu-latest]
+        crate: [utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: benchmark - ${{ matrix.platform }} - ${{ matrix.crate }}
+    name: Benchmark - ${{ matrix.crate }} - ${{ matrix.platform }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - uses: Swatinem/rust-cache@v2
       - uses: boa-dev/criterion-compare-action@v3
         with:
@@ -170,21 +199,21 @@ jobs:
           cwd: ${{ matrix.crate }}
 
   benchmark-rln:
-    # run only in pull requests
-    if: github.event_name == 'pull_request'
+    # run only on ready PRs
+    if: github.event_name == 'pull_request' && !github.event.pull_request.draft
     strategy:
       matrix:
-        # we run benchmark tests only on ubuntu
-        platform: [ ubuntu-latest ]
-        crate: [ rln ]
-        feature: [ "default", "arkzkey" ]
+        # run benchmark tests only on ubuntu
+        platform: [ubuntu-latest]
+        crate: [rln]
+        feature: ["default"]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: benchmark - ${{ matrix.platform }} - ${{ matrix.crate }} - ${{ matrix.feature }}
+    name: Benchmark - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - uses: Swatinem/rust-cache@v2
       - uses: boa-dev/criterion-compare-action@v3
         with:

.github/workflows/nightly-release.yml

@@ -6,43 +6,45 @@ on:
 
 jobs:
   linux:
-    strategy:
-      matrix:
-        feature: [ "default", "arkzkey", "stateless" ]
-        target:
-          - x86_64-unknown-linux-gnu
-          - aarch64-unknown-linux-gnu
-          # - i686-unknown-linux-gnu
-        include:
-          - feature: stateless
-            cargo_args: --exclude rln-cli
     name: Linux build
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        features:
+          - ["stateless"]
+          - ["stateless", "parallel"]
+          - ["pmtree-ft"]
+          - ["pmtree-ft", "parallel"]
+          - ["fullmerkletree"]
+          - ["fullmerkletree", "parallel"]
+          - ["optimalmerkletree"]
+          - ["optimalmerkletree", "parallel"]
+        target: [x86_64-unknown-linux-gnu, aarch64-unknown-linux-gnu]
+    env:
+      FEATURES_CARGO: ${{ join(matrix.features, ',') }}
+      FEATURES_TAG: ${{ join(matrix.features, '-') }}
+      TARGET: ${{ matrix.target }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
-          toolchain: stable
-          override: true
-          target: ${{ matrix.target }}
+          target: ${{ env.TARGET }}
       - uses: Swatinem/rust-cache@v2
       - name: Install dependencies
         run: make installdeps
-      - name: cross build
+      - name: Cross build
         run: |
-          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace ${{ matrix.cargo_args }}
+          cross build --release --target $TARGET --no-default-features --features "$FEATURES_CARGO" --workspace
           mkdir release
-          cp target/${{ matrix.target }}/release/librln* release/
-          tar -czvf ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz release/
-
+          cp target/$TARGET/release/librln* release/
+          tar -czvf $TARGET-$FEATURES_TAG-rln.tar.gz release/
       - name: Upload archive artifact
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.target }}-${{ matrix.feature }}-archive
-          path: ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz
+          name: ${{ env.TARGET }}-${{ env.FEATURES_TAG }}-archive
+          path: ${{ env.TARGET }}-${{ env.FEATURES_TAG }}-rln.tar.gz
           retention-days: 2
 
   macos:
@@ -50,82 +52,107 @@ jobs:
     runs-on: macos-latest
     strategy:
       matrix:
-        feature: [ "default", "arkzkey", "stateless" ]
-        target:
-          - x86_64-apple-darwin
-          - aarch64-apple-darwin
-        include:
-          - feature: stateless
-            cargo_args: --exclude rln-cli
+        features:
+          - ["stateless"]
+          - ["stateless", "parallel"]
+          - ["pmtree-ft"]
+          - ["pmtree-ft", "parallel"]
+          - ["fullmerkletree"]
+          - ["fullmerkletree", "parallel"]
+          - ["optimalmerkletree"]
+          - ["optimalmerkletree", "parallel"]
+        target: [x86_64-apple-darwin, aarch64-apple-darwin]
+    env:
+      FEATURES_CARGO: ${{ join(matrix.features, ',') }}
+      FEATURES_TAG: ${{ join(matrix.features, '-') }}
+      TARGET: ${{ matrix.target }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
-          toolchain: stable
-          override: true
-          target: ${{ matrix.target }}
+          target: ${{ env.TARGET }}
       - uses: Swatinem/rust-cache@v2
       - name: Install dependencies
         run: make installdeps
-      - name: cross build
+      - name: Cross build
         run: |
-          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace ${{ matrix.cargo_args }}
+          cross build --release --target $TARGET --no-default-features --features "$FEATURES_CARGO" --workspace
           mkdir release
-          cp target/${{ matrix.target }}/release/librln* release/
-          tar -czvf ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz release/
-
+          cp target/$TARGET/release/librln* release/
+          tar -czvf $TARGET-$FEATURES_TAG-rln.tar.gz release/
       - name: Upload archive artifact
         uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.target }}-${{ matrix.feature }}-archive
-          path: ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz
+          name: ${{ env.TARGET }}-${{ env.FEATURES_TAG }}-archive
+          path: ${{ env.TARGET }}-${{ env.FEATURES_TAG }}-rln.tar.gz
           retention-days: 2
 
-  browser-rln-wasm:
-    name: Browser build (RLN WASM)
+  rln-wasm:
+    name: Build rln-wasm
     runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        feature:
+          - "default"
+          - "parallel"
+          - "utils"
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
-          toolchain: stable
-          override: true
+          targets: wasm32-unknown-unknown
+      - name: Install nightly toolchain
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          components: rust-src
+          targets: wasm32-unknown-unknown
       - uses: Swatinem/rust-cache@v2
       - name: Install dependencies
         run: make installdeps
-      - name: cross make build
+      - name: Build rln-wasm package
         run: |
-          cross make build
-          mkdir release
-          cp pkg/** release/
-          tar -czvf browser-rln-wasm.tar.gz release/
-        working-directory: rln-wasm
+          if [[ ${{ matrix.feature }} == "parallel" ]]; then
+            env CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_RUSTFLAGS="-C target-feature=+atomics,+bulk-memory,+mutable-globals -C link-arg=--shared-memory -C link-arg=--max-memory=1073741824 -C link-arg=--import-memory -C link-arg=--export=__wasm_init_tls -C link-arg=--export=__tls_size -C link-arg=--export=__tls_align -C link-arg=--export=__tls_base" \
+            rustup run nightly wasm-pack build --release --target web --scope waku \
+            --features parallel -Z build-std=panic_abort,std
+            sed -i.bak 's/rln-wasm/zerokit-rln-wasm-parallel/g' pkg/package.json && rm pkg/package.json.bak
+          elif [[ ${{ matrix.feature }} == "utils" ]]; then
+            wasm-pack build --release --target web --scope waku --no-default-features --features utils
+            sed -i.bak 's/rln-wasm/zerokit-rln-wasm-utils/g' pkg/package.json && rm pkg/package.json.bak
+          else
+            wasm-pack build --release --target web --scope waku
+            sed -i.bak 's/rln-wasm/zerokit-rln-wasm/g' pkg/package.json && rm pkg/package.json.bak
+          fi
 
+          jq '. + {keywords: ["zerokit", "rln", "wasm"]}' pkg/package.json > pkg/package.json.tmp && \
+          mv pkg/package.json.tmp pkg/package.json
+
+          mkdir release
+          cp -r pkg/* release/
+          tar -czvf rln-wasm-${{ matrix.feature }}.tar.gz release/
+        working-directory: rln-wasm
       - name: Upload archive artifact
         uses: actions/upload-artifact@v4
         with:
-          name: browser-rln-wasm-archive
-          path: rln-wasm/browser-rln-wasm.tar.gz
+          name: rln-wasm-${{ matrix.feature }}-archive
+          path: rln-wasm/rln-wasm-${{ matrix.feature }}.tar.gz
           retention-days: 2
 
   prepare-prerelease:
     name: Prepare pre-release
-    needs: [ linux, macos, browser-rln-wasm ]
+    needs: [linux, macos, rln-wasm]
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           ref: master
       - name: Download artifacts
         uses: actions/download-artifact@v4
-
       - name: Delete tag
         uses: dev-drprasad/delete-tag-and-release@v0.2.1
         with:
@@ -133,7 +160,6 @@ jobs:
           tag_name: nightly
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
       - name: Create prerelease
         run: |
           start_tag=$(gh release list -L 2 --exclude-drafts | grep -v nightly | cut -d$'\t' -f3 | sed -n '1p')
@@ -145,7 +171,6 @@ jobs:
             *-archive/*.tar.gz \
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-
       - name: Delete artifacts
         uses: geekyeggo/delete-artifact@v5
         with:

.github/workflows/sync-labels.yml

@@ -9,7 +9,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: micnncim/action-label-syncer@v1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -1,20 +1,29 @@
+# Common files to ignore in Rust projects
 .DS_Store
 .idea
 *.log
 tmp/
-rln/pmtree_db
-rln-cli/database
 
-# Generated by Cargo
-# will have compiled files and executables
-debug/
-target/
+# Generated by Cargo will have compiled files and executables
+/target
 
 # Generated by Nix
-result/
+result
 
 # These are backup files generated by rustfmt
 **/*.rs.bk
 
 # MSVC Windows builds of rustc generate these, which store debugging information
 *.pdb
+
+# FFI C examples
+rln/ffi_c_examples/main
+rln/ffi_c_examples/rln.h
+rln/ffi_c_examples/database
+
+# FFI Nim examples
+rln/ffi_nim_examples/main
+rln/ffi_nim_examples/database
+
+# Vscode
+.vscode

CHANGELOG.md

@@ -1,29 +0,0 @@
-# CHANGE LOG
-
-## 2023-02-28 v0.2
-
-This release contains:
-
-- Improved code quality
-- Allows consumers of zerokit RLN to set leaves to the Merkle Tree from an arbitrary index. Useful for batching updates to the Merkle Tree.
-- Improved performance for proof generation and verification
-- rln_wasm which allows for the consumption of RLN through a WebAssembly interface
-- Refactored to generate Semaphore-compatible credentials
-- Dual License under Apache 2.0 and MIT
-- RLN compiles as a static library, which can be consumed through a C FFI
-
-## 2022-09-19 v0.1
-
-Initial beta release.
-
-This release contains:
-
-- RLN Module with API to manage, compute and verify [RLN](https://rfc.vac.dev/spec/32/) zkSNARK proofs and RLN primitives.
-- This can be consumed either as a Rust API or as a C FFI. The latter means it can be easily consumed through other environments, such as [Go](https://github.com/status-im/go-zerokit-rln/blob/master/rln/librln.h) or [Nim](https://github.com/status-im/nwaku/blob/4745c7872c69b5fd5c6ddab36df9c5c3d55f57c3/waku/v2/protocol/waku_rln_relay/waku_rln_relay_types.nim).
-
-It also contains the following examples and experiments:
-
-- Basic [example wrapper](https://github.com/vacp2p/zerokit/tree/master/multiplier) around a simple Circom circuit to show Circom integration through ark-circom and FFI.
-- Experimental [Semaphore wrapper](https://github.com/vacp2p/zerokit/tree/master/semaphore).
-
-Feedback welcome! You can either [open an issue](https://github.com/vacp2p/zerokit/issues) or come talk to us in our [Vac Discord](https://discord.gg/PQFdubGt6d) #zerokit channel.

CONTRIBUTING.md

@@ -0,0 +1,197 @@
+# Contributing to Zerokit
+
+Thank you for your interest in contributing to Zerokit!
+This guide will discuss how the Zerokit team handles [Commits](#commits),
+[Pull Requests](#pull-requests) and [Merging](#merging).
+
+**Note:** We won't force external contributors to follow this verbatim.
+Following these guidelines definitely helps us in accepting your contributions.
+
+## Getting Started
+
+1. Fork the repository
+2. Create a feature branch: `git checkout -b fix/your-bug-fix` or `git checkout -b feat/your-feature-name`
+3. Make your changes following our guidelines
+4. Ensure relevant tests pass (see [testing guidelines](#building-and-testing))
+5. Commit your changes (signed commits are highly encouraged - see [commit guidelines](#commits))
+6. Push and create a Pull Request
+
+## Development Setup
+
+### Prerequisites
+
+Install the required dependencies:
+
+```bash
+make installdeps
+```
+
+Or use Nix:
+
+```bash
+nix develop
+```
+
+### Building and Testing
+
+```bash
+# Build all crates
+make build
+
+# Run standard tests
+make test
+
+# Module-specific testing
+cd rln && cargo make test_stateless        # Test stateless features
+cd rln-wasm && cargo make test_browser     # Test in browser headless mode
+cd rln-wasm && cargo make test_parallel    # Test parallel features
+```
+
+### Tools
+
+We recommend using the [markdownlint extension](https://marketplace.visualstudio.com/items?itemName=DavidAnson.vscode-markdownlint)
+for VS Code to maintain consistent documentation formatting.
+
+## Commits
+
+We want to keep our commits small and focused.
+This allows for easily reviewing individual commits and/or
+splitting up pull requests when they grow too big.
+Additionally, this allows us to merge smaller changes quicker and release more often.
+
+**All commits must be GPG signed.**
+This ensures the authenticity and integrity of contributions.
+
+### Conventional Commits
+
+When making the commit, write the commit message
+following the [Conventional Commits (v1.0.0)](https://www.conventionalcommits.org/en/v1.0.0/) specification.
+Following this convention allows us to provide an automated release process
+that also generates a detailed Changelog.
+
+As described by the specification, our commit messages should be written as:
+
+```markdown
+<type>[optional scope]: <description>
+
+[optional body]
+
+[optional footer(s)]
+```
+
+Some examples of this pattern include:
+
+```markdown
+feat(rln): add parallel witness calculation support
+```
+
+```markdown
+fix(rln-wasm): resolve memory leak in browser threading
+```
+
+```markdown
+docs: update RLN protocol flow documentation
+```
+
+#### Scopes
+
+Use scopes to improve the Changelog:
+
+- `rln` - Core RLN implementation
+- `rln-cli` - Command-line interface
+- `rln-wasm` - WebAssembly bindings
+- `utils` - Cryptographic utilities (Merkle trees, Poseidon hash)
+- `ci` - Continuous integration
+
+#### Breaking Changes
+
+Mark breaking changes by adding `!` after the type:
+
+```markdown
+feat(rln)!: change proof generation API
+```
+
+## Pull Requests
+
+Before creating a pull request, search for related issues.
+If none exist, create an issue describing the problem you're solving.
+
+### CI Flow
+
+Our continuous integration automatically runs when you create a Pull Request:
+
+- **Build verification**: All crates compile successfully
+- **Test execution**: Comprehensive testing across all modules and feature combinations
+- **Code formatting**: `cargo fmt` compliance
+- **Linting**: `cargo clippy` checks
+- **Cross-platform builds**: Testing on multiple platforms
+
+Ensure the following commands pass before submitting:
+
+```bash
+# Format code
+cargo fmt --all
+
+# Check for common mistakes
+cargo clippy --all-targets
+
+# Run all tests
+make test
+```
+
+### Adding Tests
+
+Include tests for new functionality:
+
+- **Unit tests** for specific functions
+- **Integration tests** for broader functionality
+- **WASM tests** for browser compatibility
+
+### Typos and Small Changes
+
+For minor fixes like typos, please report them as issues instead of opening PRs.
+This helps us manage resources effectively and ensures meaningful contributions.
+
+## Merging
+
+We use "squash merging" for all pull requests.
+This combines all commits into one commit, so keep pull requests small and focused.
+
+### Requirements
+
+- CI checks must pass
+- At least one maintainer review and approval
+- All review feedback addressed
+
+### Squash Guidelines
+
+When squashing, update the commit title to be a proper Conventional Commit and
+include any other relevant commits in the body:
+
+```markdown
+feat(rln): implement parallel witness calculation (#123)
+
+fix(tests): resolve memory leak in test suite
+chore(ci): update rust toolchain version
+```
+
+## Roadmap Alignment
+
+Please refer to our [project roadmap](https://roadmap.vac.dev/) for current development priorities.
+Consider how your changes align with these strategic goals when contributing.
+
+## Getting Help
+
+- **Issues**: Create a GitHub issue for bugs or feature requests
+- **Discussions**: Use GitHub Discussions for questions
+- **Documentation**: Check existing docs and unit tests for examples
+
+## License
+
+By contributing to Zerokit, you agree that your contributions will be licensed under both MIT and
+Apache 2.0 licenses, consistent with the project's dual licensing.
+
+## Additional Resources
+
+- [Conventional Commits Guide](https://www.conventionalcommits.org/en/v1.0.0/)
+- [Project GitHub Repository](https://github.com/vacp2p/zerokit)

Cargo.toml

@@ -1,10 +1,10 @@
 [workspace]
-members = ["rln", "rln-cli", "rln-wasm", "utils"]
-default-members = ["rln", "rln-cli", "rln-wasm", "utils"]
+members = ["rln", "utils"]
+exclude = ["rln-cli", "rln-wasm"]
 resolver = "2"
 
 # Compilation profile for any non-workspace member.
-# Dependencies are optimized, even in a dev build. This improves dev performance
-# while having neglible impact on incremental build times.
+# Dependencies are optimized, even in a dev build.
+# This improves dev performance while having negligible impact on incremental build times.
 [profile.dev.package."*"]
 opt-level = 3

Makefile

@@ -1,6 +1,6 @@
 .PHONY: all installdeps build test bench clean
 
-all: .pre-build build
+all: installdeps build
 
 .fetch-submodules:
 	@git submodule update --init --recursive
@@ -13,29 +13,26 @@ endif
 
 installdeps: .pre-build
 ifeq ($(shell uname),Darwin)
-	@brew update
-	@brew install cmake ninja
+	@brew install ninja
 else ifeq ($(shell uname),Linux)
-	@sudo apt-get update
-	@sudo apt-get install -y cmake ninja-build
-endif
-	@if [ ! -d "$$HOME/.nvm" ]; then \
-		curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.2/install.sh | bash; \
+	@if [ -f /etc/os-release ] && grep -q "ID=nixos" /etc/os-release; then \
+		echo "Detected NixOS, skipping apt installation."; \
+	else \
+		sudo apt update; \
+		sudo apt install -y cmake ninja-build; \
 	fi
-	@bash -c 'export NVM_DIR="$$HOME/.nvm" && \
-		[ -s "$$NVM_DIR/nvm.sh" ] && \. "$$NVM_DIR/nvm.sh" && \
-		nvm install 22.14.0 && \
-		nvm use 22.14.0'
-	@curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
-	@echo "\033[1;32m>>> Now run this command to activate Node.js 22.14.0: \033[1;33msource $$HOME/.nvm/nvm.sh && nvm use 22.14.0\033[0m"
+endif
+	@which wasm-pack > /dev/null && wasm-pack --version | grep -q "0.13.1" || cargo install wasm-pack --version=0.13.1
+	@test -s "$$HOME/.nvm/nvm.sh" || curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.2/install.sh | bash
+	@bash -c '. "$$HOME/.nvm/nvm.sh"; [ "$$(node -v 2>/dev/null)" = "v22.14.0" ] || nvm install 22.14.0; nvm use 22.14.0; nvm alias default 22.14.0'
 
-build: .pre-build
+build: installdeps
 	@cargo make build
 
-test: .pre-build
+test: build
 	@cargo make test
 
-bench: .pre-build
+bench: build
 	@cargo make bench
 
 clean:

README.md

@@ -12,31 +12,37 @@ A collection of Zero Knowledge modules written in Rust and designed to be used i
 Zerokit provides zero-knowledge cryptographic primitives with a focus on performance, security, and usability.
 The current focus is on Rate-Limiting Nullifier [RLN](https://github.com/Rate-Limiting-Nullifier) implementation.
 
-Current implementation is based on the following [specification](https://github.com/vacp2p/rfc-index/blob/main/vac/raw/rln-v2.md)
+Current implementation is based on the following
+[specification](https://rfc.vac.dev/vac/raw/rln-v2)
 and focused on RLNv2 which allows to set a rate limit for the number of messages that can be sent by a user.
 
 ## Features
 
-- **RLN Implementation**: Efficient Rate-Limiting Nullifier using zkSNARKs
+- **RLN Implementation**: Efficient Rate-Limiting Nullifier using zkSNARK
 - **Circom Compatibility**: Uses Circom-based circuits for RLN
-- **Cross-Platform**: Support for multiple architectures (see compatibility note below)
+- **Cross-Platform**: Support for multiple architectures with cross-compilation
 - **FFI-Friendly**: Easy to integrate with other languages
+- **WASM Support**: Can be compiled to WebAssembly for web applications
 
 ## Architecture
 
-Zerokit currently focuses on RLN (Rate-Limiting Nullifier) implementation using [Circom](https://iden3.io/circom) circuits through ark-circom, providing an alternative to existing native Rust implementations.
+Zerokit currently focuses on RLN (Rate-Limiting Nullifier) implementation using [Circom](https://iden3.io/circom)
+circuits through ark-circom, providing an alternative to existing native Rust implementations.
 
 ## Build and Test
 
-> [!IMPORTANT]
-> For WASM support or x32 architecture builds, use version `0.6.1`. The current version has dependency issues for these platforms. WASM support will return in a future release.
-
 ### Install Dependencies
 
 ```bash
 make installdeps
 ```
 
+#### Use Nix to install dependencies
+
+```bash
+nix develop
+```
+
 ### Build and Test All Crates
 
 ```bash
@@ -69,8 +75,8 @@ The execution graph file used by this code has been generated by means of the sa
 
 > [!IMPORTANT]
 > The circom-witnesscalc code fragments have been borrowed instead of depending on this crate,
-    because its types of input and output data were incompatible with the corresponding zerokit code fragments,
-    and circom-witnesscalc has some dependencies, which are redundant for our purpose.
+> because its types of input and output data were incompatible with the corresponding zerokit code fragments,
+> and circom-witnesscalc has some dependencies, which are redundant for our purpose.
 
 ## Documentation
 

flake.lock

@@ -2,23 +2,44 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1740603184,
-        "narHash": "sha256-t+VaahjQAWyA+Ctn2idyo1yxRIYpaDxMgHkgCNiMJa4=",
+        "lastModified": 1757590060,
+        "narHash": "sha256-EWwwdKLMZALkgHFyKW7rmyhxECO74+N+ZO5xTDnY/5c=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "f44bd8ca21e026135061a0a57dcf3d0775b67a49",
+        "rev": "0ef228213045d2cdb5a169a95d63ded38670b293",
         "type": "github"
       },
       "original": {
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "f44bd8ca21e026135061a0a57dcf3d0775b67a49",
+        "rev": "0ef228213045d2cdb5a169a95d63ded38670b293",
         "type": "github"
       }
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1748399823,
+        "narHash": "sha256-kahD8D5hOXOsGbNdoLLnqCL887cjHkx98Izc37nDjlA=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "d68a69dc71bc19beb3479800392112c2f6218159",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
       }
     }
   },

flake.nix

@@ -1,12 +1,21 @@
 {
   description = "A flake for building zerokit";
 
-  inputs = {
-    # Version 24.11
-    nixpkgs.url = "github:NixOS/nixpkgs?rev=f44bd8ca21e026135061a0a57dcf3d0775b67a49";
+  nixConfig = {
+    extra-substituters = [ "https://nix-cache.status.im/" ];
+    extra-trusted-public-keys = [ "nix-cache.status.im-1:x/93lOfLU+duPplwMSBR+OlY4+mo+dCN7n0mr4oPwgY=" ];
   };
 
-  outputs = { self, nixpkgs }: 
+  inputs = {
+    # Version 24.11
+    nixpkgs.url = "github:NixOS/nixpkgs?rev=0ef228213045d2cdb5a169a95d63ded38670b293";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, rust-overlay }:
     let
       stableSystems = [
         "x86_64-linux" "aarch64-linux"
@@ -15,22 +24,58 @@
         "i686-windows"
       ];
       forAllSystems = nixpkgs.lib.genAttrs stableSystems;
-      pkgsFor = forAllSystems (system: import nixpkgs { inherit system; });
+
+      pkgsFor = forAllSystems (
+        system: import nixpkgs {
+          inherit system;
+          config = {
+            android_sdk.accept_license = true;
+            allowUnfree = true;
+          };
+          overlays = [
+            (import rust-overlay)
+            (f: p: { inherit rust-overlay; })
+          ];
+        }
+      );
     in rec
     {
       packages = forAllSystems (system: let
         pkgs = pkgsFor.${system};
+        buildPackage = pkgs.callPackage ./nix/default.nix;
+        buildRln = (buildPackage { src = self; project = "rln"; }).override;
       in rec {
-        zerokit-android-arm64 = pkgs.callPackage ./nix/default.nix { target-platform="aarch64-android-prebuilt"; rust-target= "aarch64-linux-android"; };
-        default = zerokit-android-arm64;
+        rln = buildRln { };
+
+        rln-linux-arm64 = buildRln {
+          target-platform = "aarch64-multiplatform";
+          rust-target = "aarch64-unknown-linux-gnu";
+        };
+
+        rln-android-arm64 = buildRln {
+          target-platform = "aarch64-android-prebuilt";
+          rust-target = "aarch64-linux-android";
+        };
+
+        rln-ios-arm64 = buildRln {
+          target-platform = "aarch64-darwin";
+          rust-target = "aarch64-apple-ios";
+        };
+
+        # TODO: Remove legacy name for RLN android library
+        zerokit-android-arm64 = rln-android-arm64;
+
+        default = rln;
       });
 
       devShells = forAllSystems (system: let
         pkgs = pkgsFor.${system};
       in {
         default = pkgs.mkShell {
-          inputsFrom = [
-            packages.${system}.default
+          buildInputs = with pkgs; [
+            git cmake cargo-make rustup
+            binaryen ninja gnuplot
+            rust-bin.stable.latest.default
           ];
         };
       });

nix/default.nix

@@ -1,33 +1,62 @@
 {
   pkgs,
-  target-platform ? "aarch64-android-prebuilt",
-  rust-target ? "aarch64-linux-android",
+  rust-overlay,
+  project,
+  src ? ../.,
+  release ? true,
+  target-platform ? null,
+  rust-target ? null,
+  features ? null,
 }:
 
-pkgs.pkgsCross.${target-platform}.rustPlatform.buildRustPackage {
-  pname = "zerokit";
-  version = "nightly";
+let
+  # Use cross-compilation if target-platform is specified.
+  targetPlatformPkgs = if target-platform != null
+    then pkgs.pkgsCross.${target-platform}
+    else pkgs;
 
-  src = ../.;
+  rust-bin = rust-overlay.lib.mkRustBin { } targetPlatformPkgs.buildPackages;
+
+  # Use Rust and Cargo versions from rust-overlay.
+  rustPlatform = targetPlatformPkgs.makeRustPlatform {
+    cargo = rust-bin.stable.latest.minimal;
+    rustc = rust-bin.stable.latest.minimal;
+  };
+in rustPlatform.buildRustPackage {
+  pname = "zerokit";
+  version = if src ? rev then src.rev else "nightly";
+
+  # Improve caching of sources
+  src = builtins.path { path = src; name = "zerokit"; };
 
   cargoLock = {
-    lockFile = ../Cargo.lock;
+    lockFile = src + "/Cargo.lock";
     allowBuiltinFetchGit = true;
   };
 
+  nativeBuildInputs = [ pkgs.rust-cbindgen ];
+
+  doCheck = false;
+
   CARGO_HOME = "/tmp";
 
   buildPhase = ''
-    pushd rln
-    cargo rustc --crate-type=cdylib --release --lib --target=${rust-target}
-    popd
+    cargo build --lib \
+      ${if release             then "--release" else ""} \
+      ${if rust-target != null then "--target=${rust-target}" else ""} \
+      ${if features != null    then "--features=${features}" else ""} \
+      --manifest-path ${project}/Cargo.toml
   '';
 
   installPhase = ''
-    mkdir -p $out/
-    cp ./target/${rust-target}/release/librln.so $out/
+    set -eu
+    mkdir -p $out/lib
+    find target -type f -name 'librln.*' -not -path '*/deps/*' -exec cp -v '{}' "$out/lib/" \;
+    mkdir -p $out/include
+    cbindgen ${src}/rln -l c > "$out/include/rln.h"
   '';
 
+
   meta = with pkgs.lib; {
     description = "Zerokit";
     license = licenses.mit;

rln-cli/.gitignore

@@ -0,0 +1,20 @@
+# Common files to ignore in Rust projects
+.DS_Store
+.idea
+*.log
+tmp/
+
+# Generated by Cargo will have compiled files and executables
+/target
+
+# Generated by rln-cli
+/database
+
+# Generated by Nix
+result
+
+# These are backup files generated by rustfmt
+**/*.rs.bk
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb

rln-cli/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rln-cli"
-version = "0.4.0"
+version = "0.5.0"
 edition = "2021"
 
 [[example]]
@@ -13,15 +13,15 @@ path = "src/examples/stateless.rs"
 required-features = ["stateless"]
 
 [dependencies]
-rln = { path = "../rln", default-features = false }
-zerokit_utils = { path = "../utils" }
-clap = { version = "4.5.35", features = ["cargo", "derive", "env"] }
-clap_derive = { version = "4.5.32" }
-color-eyre = "0.6.3"
-serde_json = "1.0"
-serde = { version = "1.0", features = ["derive"] }
+rln = { path = "../rln", version = "1.0.0", default-features = false }
+zerokit_utils = { path = "../utils", version = "1.0.0", default-features = false }
+clap = { version = "4.5.53", features = ["cargo", "derive", "env"] }
+serde_json = "1.0.145"
+serde = { version = "1.0.228", features = ["derive"] }
 
 [features]
-default = []
-arkzkey = ["rln/arkzkey"]
-stateless = ["rln/stateless"]
+default = ["rln/pmtree-ft", "rln/parallel"]
+stateless = ["rln/stateless", "rln/parallel"]
+
+[package.metadata.docs.rs]
+all-features = true

rln-cli/README.md

@@ -1,45 +1,10 @@
 # Zerokit RLN-CLI
 
-The Zerokit RLN-CLI provides a command-line interface for interacting with the public API of the [Zerokit RLN Module](../rln/README.md).
-
-It also contain:
-
-+ [Relay Example](#relay-example) to demonstrate the use of the RLN module for spam prevention.
-+ [Stateless Example](#stateless-example) to demonstrate the use of the RLN module for stateless features.
-
-## Configuration
-
-The CLI can be configured using a JSON configuration file (see the [example](example.config.json)).
-
-You can specify the configuration file path using the `RLN_CONFIG_PATH` environment variable:
-
-```bash
-export RLN_CONFIG_PATH=example.config.json
-```
-
-Alternatively, you can provide the configuration file path as an argument for each command:
-
-```bash
-RLN_CONFIG_PATH=example.config.json cargo run -- <SUBCOMMAND> [OPTIONS]
-```
-
-If the configuration file is empty, default settings will be used, but the tree data folder will be temporary and not saved to the preconfigured path.
-
-We recommend using the example config, as all commands (except `new` and `create-with-params`) require an initialized RLN instance.
-
-## Feature Flags
-
-The CLI supports optional features. To enable the **arkzkey** feature, run:
-
-```bash
-cargo run --features arkzkey -- <SUBCOMMAND> [OPTIONS]
-```
-
-For more details, refer to the [Zerokit RLN Module](../rln/README.md) documentation.
+The Zerokit RLN-CLI provides a command-line interface examples on how to use public API of the [Zerokit RLN Module](../rln/README.md).
 
 ## Relay Example
 
-The following [Example](src/examples/relay.rs) demonstrates how RLN enables spam prevention in anonymous environments for multple users.
+The following [Relay Example](src/examples/relay.rs) demonstrates how RLN enables spam prevention in anonymous environments for multple users.
 
 You can run the example using the following command:
 
@@ -47,124 +12,18 @@ You can run the example using the following command:
 cargo run --example relay
 ```
 
-or with the **arkzkey** feature flag:
+You can also change **MESSAGE_LIMIT** and **TREE_DEPTH** in the [relay.rs](src/examples/relay.rs) file to see how the RLN instance behaves with different parameters.
 
-```bash
-cargo run --example relay --features arkzkey
-```
-
-You can also change **MESSAGE_LIMIT** and **TREEE_HEIGHT** in the [relay.rs](src/examples/relay.rs) file to see how the RLN instance behaves with different parameters.
-
-The customize **TREEE_HEIGHT** constant differs from the default value of `20` should follow [Custom Circuit Compilation](../rln/README.md#advanced-custom-circuit-compilation) instructions.
+The customize **TREE_DEPTH** constant differs from the default value of `20` should follow [Custom Circuit Compilation](../rln/README.md#advanced-custom-circuit-compilation) instructions.
 
 ## Stateless Example
 
-The following [Example](src/examples/stateless.rs) demonstrates how RLN can be used for stateless features by creating the Merkle tree outside of RLN instance.
+The following [Stateless Example](src/examples/stateless.rs) demonstrates how RLN can be used for stateless features by creating the Merkle tree outside of RLN instance.
 
 This example function similarly to the [Relay Example](#relay-example) but uses a stateless RLN and seperate Merkle tree.
 
 You can run the example using the following command:
 
 ```bash
-cargo run --example stateless --features stateless
-```
-
-or with the **arkzkey** feature flag:
-
-```bash
-cargo run --example stateless --features stateless,arkzkey
-```
-
-## CLI Commands
-
-### Instance Management
-
-To initialize a new RLN instance:
-
-```bash
-cargo run new --tree-height <HEIGHT>
-```
-
-To initialize an RLN instance with custom parameters:
-
-```bash
-cargo run new-with-params --resources-path <PATH> --tree-height <HEIGHT>
-```
-
-To update the Merkle tree height:
-
-```bash
-cargo run set-tree --tree-height <HEIGHT>
-```
-
-### Leaf Operations
-
-To set a single leaf:
-
-```bash
-cargo run set-leaf --index <INDEX> --input <INPUT_PATH>
-```
-
-To set multiple leaves:
-
-```bash
-cargo run set-multiple-leaves --index <START_INDEX> --input <INPUT_PATH>
-```
-
-To reset multiple leaves:
-
-```bash
-cargo run reset-multiple-leaves --input <INPUT_PATH>
-```
-
-To set the next available leaf:
-
-```bash
-cargo run set-next-leaf --input <INPUT_PATH>
-```
-
-To delete a specific leaf:
-
-```bash
-cargo run delete-leaf --index <INDEX>
-```
-
-### Proof Operations
-
-To generate a proof:
-
-```bash
-cargo run prove --input <INPUT_PATH>
-```
-
-To generate an RLN proof:
-
-```bash
-cargo run generate-proof --input <INPUT_PATH>
-```
-
-To verify a proof:
-
-```bash
-cargo run verify --input <PROOF_PATH>
-```
-
-To verify a proof with multiple Merkle roots:
-
-```bash
-cargo run verify-with-roots --input <INPUT_PATH> --roots <ROOTS_PATH>
-```
-
-### Tree Information
-
-To retrieve the current Merkle root:
-
-```bash
-cargo run get-root
-```
-
-To obtain a Merkle proof for a specific index:
-
-```bash
-cargo run get-proof --index <INDEX>
+cargo run --example stateless --no-default-features --features stateless
 ```

rln-cli/example.config.json

@@ -1,11 +0,0 @@
-{
-  "tree_config": {
-    "path": "database",
-    "temporary": false,
-    "cache_capacity": 150000,
-    "flush_every_ms": 12000,
-    "mode": "HighThroughput",
-    "use_compression": false
-  },
-  "tree_height": 20
-}

rln-cli/src/commands.rs

@@ -1,69 +0,0 @@
-use std::path::PathBuf;
-
-use clap::Subcommand;
-use rln::circuit::TEST_TREE_HEIGHT;
-
-#[derive(Subcommand)]
-pub(crate) enum Commands {
-    New {
-        #[arg(short, long, default_value_t = TEST_TREE_HEIGHT)]
-        tree_height: usize,
-    },
-    NewWithParams {
-        #[arg(short, long, default_value_t = TEST_TREE_HEIGHT)]
-        tree_height: usize,
-        #[arg(short, long, default_value = "../rln/resources/tree_height_20")]
-        resources_path: PathBuf,
-    },
-    SetTree {
-        #[arg(short, long, default_value_t = TEST_TREE_HEIGHT)]
-        tree_height: usize,
-    },
-    SetLeaf {
-        #[arg(short, long)]
-        index: usize,
-        #[arg(short, long)]
-        input: PathBuf,
-    },
-    SetMultipleLeaves {
-        #[arg(short, long)]
-        index: usize,
-        #[arg(short, long)]
-        input: PathBuf,
-    },
-    ResetMultipleLeaves {
-        #[arg(short, long)]
-        input: PathBuf,
-    },
-    SetNextLeaf {
-        #[arg(short, long)]
-        input: PathBuf,
-    },
-    DeleteLeaf {
-        #[arg(short, long)]
-        index: usize,
-    },
-    GetRoot,
-    GetProof {
-        #[arg(short, long)]
-        index: usize,
-    },
-    Prove {
-        #[arg(short, long)]
-        input: PathBuf,
-    },
-    Verify {
-        #[arg(short, long)]
-        input: PathBuf,
-    },
-    GenerateProof {
-        #[arg(short, long)]
-        input: PathBuf,
-    },
-    VerifyWithRoots {
-        #[arg(short, long)]
-        input: PathBuf,
-        #[arg(short, long)]
-        roots: PathBuf,
-    },
-}

rln-cli/src/config.rs

@@ -1,38 +0,0 @@
-use std::{fs::File, io::Read, path::PathBuf};
-
-use color_eyre::Result;
-use serde::{Deserialize, Serialize};
-use serde_json::Value;
-
-pub const RLN_CONFIG_PATH: &str = "RLN_CONFIG_PATH";
-
-#[derive(Default, Serialize, Deserialize)]
-pub(crate) struct Config {
-    pub inner: Option<InnerConfig>,
-}
-
-#[derive(Default, Serialize, Deserialize)]
-pub(crate) struct InnerConfig {
-    pub tree_height: usize,
-    pub tree_config: Value,
-}
-
-impl Config {
-    pub(crate) fn load_config() -> Result<Config> {
-        match std::env::var(RLN_CONFIG_PATH) {
-            Ok(env) => {
-                let path = PathBuf::from(env);
-                let mut file = File::open(path)?;
-                let mut contents = String::new();
-                file.read_to_string(&mut contents)?;
-                let inner: InnerConfig = serde_json::from_str(&contents)?;
-                Ok(Config { inner: Some(inner) })
-            }
-            Err(_) => Ok(Config::default()),
-        }
-    }
-
-    pub(crate) fn as_bytes(&self) -> Vec<u8> {
-        serde_json::to_string(&self.inner).unwrap().into_bytes()
-    }
-}

rln-cli/src/examples/relay.rs

@@ -1,23 +1,22 @@
 use std::{
     collections::HashMap,
     fs::File,
-    io::{stdin, stdout, Cursor, Read, Write},
+    io::{stdin, stdout, Read, Write},
     path::{Path, PathBuf},
 };
 
 use clap::{Parser, Subcommand};
-use color_eyre::{eyre::eyre, Result};
-use rln::{
-    circuit::Fr,
-    hashers::{hash_to_field, poseidon_hash},
-    protocol::{keygen, prepare_prove_input, prepare_verify_input},
-    public::RLN,
-    utils::{bytes_le_to_fr, fr_to_bytes_le, generate_input_buffer},
+use rln::prelude::{
+    hash_to_field_le, keygen, poseidon_hash, recover_id_secret, Fr, IdSecret, PmtreeConfigBuilder,
+    RLNProofValues, RLNWitnessInput, RLN,
 };
+use zerokit_utils::pm_tree::Mode;
 
 const MESSAGE_LIMIT: u32 = 1;
 
-const TREEE_HEIGHT: usize = 20;
+const TREE_DEPTH: usize = 20;
+
+type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
 
 #[derive(Parser)]
 #[command(author, version, about, long_about = None)]
@@ -44,15 +43,15 @@ enum Commands {
 
 #[derive(Debug, Clone)]
 struct Identity {
-    identity_secret_hash: Fr,
+    identity_secret: IdSecret,
     id_commitment: Fr,
 }
 
 impl Identity {
     fn new() -> Self {
-        let (identity_secret_hash, id_commitment) = keygen();
+        let (identity_secret, id_commitment) = keygen().unwrap();
         Identity {
-            identity_secret_hash,
+            identity_secret,
             id_commitment,
         }
     }
@@ -60,18 +59,15 @@ impl Identity {
 
 struct RLNSystem {
     rln: RLN,
-    used_nullifiers: HashMap<[u8; 32], Vec<u8>>,
+    used_nullifiers: HashMap<Fr, RLNProofValues>,
     local_identities: HashMap<usize, Identity>,
 }
 
 impl RLNSystem {
     fn new() -> Result<Self> {
         let mut resources: Vec<Vec<u8>> = Vec::new();
-        let resources_path: PathBuf = format!("../rln/resources/tree_height_{TREEE_HEIGHT}").into();
-        #[cfg(feature = "arkzkey")]
+        let resources_path: PathBuf = format!("../rln/resources/tree_depth_{TREE_DEPTH}").into();
         let filenames = ["rln_final.arkzkey", "graph.bin"];
-        #[cfg(not(feature = "arkzkey"))]
-        let filenames = ["rln_final.zkey", "graph.bin"];
         for filename in filenames {
             let fullpath = resources_path.join(Path::new(filename));
             let mut file = File::open(&fullpath)?;
@@ -80,11 +76,19 @@ impl RLNSystem {
             file.read_exact(&mut output_buffer)?;
             resources.push(output_buffer);
         }
+        let tree_config = PmtreeConfigBuilder::new()
+            .path("./database")
+            .temporary(false)
+            .cache_capacity(1073741824)
+            .flush_every_ms(500)
+            .mode(Mode::HighThroughput)
+            .use_compression(false)
+            .build()?;
         let rln = RLN::new_with_params(
-            TREEE_HEIGHT,
+            TREE_DEPTH,
             resources[0].clone(),
             resources[1].clone(),
-            generate_input_buffer(),
+            tree_config,
         )?;
         println!("RLN instance initialized successfully");
         Ok(RLNSystem {
@@ -103,8 +107,8 @@ impl RLNSystem {
         println!("Registered users:");
         for (index, identity) in &self.local_identities {
             println!("User Index: {index}");
-            println!("+ Identity Secret Hash: {}", identity.identity_secret_hash);
-            println!("+ Identity Commitment: {}", identity.id_commitment);
+            println!("+ Identity secret: {}", *identity.identity_secret);
+            println!("+ Identity commitment: {}", identity.id_commitment);
             println!();
         }
     }
@@ -113,131 +117,112 @@ impl RLNSystem {
         let index = self.rln.leaves_set();
         let identity = Identity::new();
 
-        let rate_commitment = poseidon_hash(&[identity.id_commitment, Fr::from(MESSAGE_LIMIT)]);
-        let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
-        match self.rln.set_next_leaf(&mut buffer) {
+        let rate_commitment =
+            poseidon_hash(&[identity.id_commitment, Fr::from(MESSAGE_LIMIT)]).unwrap();
+        match self.rln.set_next_leaf(rate_commitment) {
             Ok(_) => {
                 println!("Registered User Index: {index}");
-                println!("+ Identity secret hash: {}", identity.identity_secret_hash);
-                println!("+ Identity commitment: {},", identity.id_commitment);
+                println!("+ Identity secret: {}", *identity.identity_secret);
+                println!("+ Identity commitment: {}", identity.id_commitment);
                 self.local_identities.insert(index, identity);
             }
             Err(_) => {
-                println!("Maximum user limit reached: 2^{TREEE_HEIGHT}");
+                println!("Maximum user limit reached: 2^{TREE_DEPTH}");
             }
         };
 
         Ok(index)
     }
 
-    fn generate_proof(
+    fn generate_and_verify_proof(
         &mut self,
         user_index: usize,
         message_id: u32,
         signal: &str,
         external_nullifier: Fr,
-    ) -> Result<Vec<u8>> {
+    ) -> Result<RLNProofValues> {
         let identity = match self.local_identities.get(&user_index) {
             Some(identity) => identity,
-            None => return Err(eyre!("user index {user_index} not found")),
+            None => return Err(format!("user index {user_index} not found").into()),
         };
 
-        let serialized = prepare_prove_input(
-            identity.identity_secret_hash,
-            user_index,
+        let (path_elements, identity_path_index) = self.rln.get_merkle_proof(user_index)?;
+        let x = hash_to_field_le(signal.as_bytes())?;
+
+        let witness = RLNWitnessInput::new(
+            identity.identity_secret.clone(),
             Fr::from(MESSAGE_LIMIT),
             Fr::from(message_id),
+            path_elements,
+            identity_path_index,
+            x,
             external_nullifier,
-            signal.as_bytes(),
-        );
-        let mut input_buffer = Cursor::new(serialized);
-        let mut output_buffer = Cursor::new(Vec::new());
-        self.rln
-            .generate_rln_proof(&mut input_buffer, &mut output_buffer)?;
+        )?;
+
+        let (proof, proof_values) = self.rln.generate_rln_proof(&witness)?;
 
         println!("Proof generated successfully:");
         println!("+ User Index: {user_index}");
         println!("+ Message ID: {message_id}");
         println!("+ Signal: {signal}");
 
-        Ok(output_buffer.into_inner())
+        let verified = self.rln.verify_rln_proof(&proof, &proof_values, &x)?;
+        if verified {
+            println!("Proof verified successfully");
         }
 
-    fn verify_proof(&mut self, proof_data: Vec<u8>, signal: &str) -> Result<()> {
-        let proof_with_signal = prepare_verify_input(proof_data.clone(), signal.as_bytes());
-        let mut input_buffer = Cursor::new(proof_with_signal);
+        Ok(proof_values)
+    }
 
-        match self.rln.verify_rln_proof(&mut input_buffer) {
-            Ok(true) => {
-                let nullifier = &proof_data[256..288];
-                let nullifier_key: [u8; 32] = nullifier.try_into()?;
-
-                if let Some(previous_proof) = self.used_nullifiers.get(&nullifier_key) {
-                    self.handle_duplicate_message_id(previous_proof.clone(), proof_data)?;
+    fn check_nullifier(&mut self, proof_values: RLNProofValues) -> Result<()> {
+        if let Some(&previous_proof_values) = self.used_nullifiers.get(&proof_values.nullifier) {
+            self.handle_duplicate_message_id(previous_proof_values, proof_values)?;
             return Ok(());
         }
-                self.used_nullifiers.insert(nullifier_key, proof_data);
+
+        self.used_nullifiers
+            .insert(proof_values.nullifier, proof_values);
         println!("Message verified and accepted");
-            }
-            Ok(false) => {
-                println!("Verification failed: message_id must be unique within the epoch and satisfy 0 <= message_id < MESSAGE_LIMIT: {MESSAGE_LIMIT}");
-            }
-            Err(err) => return Err(err),
-        }
         Ok(())
     }
 
     fn handle_duplicate_message_id(
         &mut self,
-        previous_proof: Vec<u8>,
-        current_proof: Vec<u8>,
+        previous_proof_values: RLNProofValues,
+        current_proof_values: RLNProofValues,
     ) -> Result<()> {
-        let x = &current_proof[192..224];
-        let y = &current_proof[224..256];
-
-        let prev_x = &previous_proof[192..224];
-        let prev_y = &previous_proof[224..256];
-        if x == prev_x && y == prev_y {
-            return Err(eyre!("this exact message and signal has already been sent"));
+        if previous_proof_values.x == current_proof_values.x
+            && previous_proof_values.y == current_proof_values.y
+        {
+            return Err("this exact message and signal has already been sent".into());
         }
 
-        let mut proof1 = Cursor::new(previous_proof);
-        let mut proof2 = Cursor::new(current_proof);
-        let mut output = Cursor::new(Vec::new());
-
-        match self
-            .rln
-            .recover_id_secret(&mut proof1, &mut proof2, &mut output)
-        {
-            Ok(_) => {
-                let output_data = output.into_inner();
-                let (leaked_identity_secret_hash, _) = bytes_le_to_fr(&output_data);
-
+        match recover_id_secret(&previous_proof_values, &current_proof_values) {
+            Ok(leaked_identity_secret) => {
                 if let Some((user_index, identity)) = self
                     .local_identities
                     .iter()
-                    .find(|(_, identity)| {
-                        identity.identity_secret_hash == leaked_identity_secret_hash
-                    })
+                    .find(|(_, identity)| identity.identity_secret == leaked_identity_secret)
                     .map(|(index, identity)| (*index, identity))
                 {
-                    let real_identity_secret_hash = identity.identity_secret_hash;
-                    if leaked_identity_secret_hash != real_identity_secret_hash {
-                        Err(eyre!("identity secret hash mismatch {leaked_identity_secret_hash} != {real_identity_secret_hash}"))
+                    let real_identity_secret = identity.identity_secret.clone();
+                    if leaked_identity_secret != real_identity_secret {
+                        Err("Identity secret mismatch: leaked_identity_secret != real_identity_secret".into())
                     } else {
-                        println!("DUPLICATE message ID detected! Reveal identity secret hash: {leaked_identity_secret_hash}");
+                        println!(
+                            "DUPLICATE message ID detected! Reveal identity secret: {}",
+                            *leaked_identity_secret
+                        );
                         self.local_identities.remove(&user_index);
                         self.rln.delete_leaf(user_index)?;
                         println!("User index {user_index} has been SLASHED");
                         Ok(())
                     }
                 } else {
-                    Err(eyre!(
-                        "user identity secret hash {leaked_identity_secret_hash} not found"
-                    ))
+                    Err("user identity secret ******** not found".into())
                 }
             }
-            Err(err) => Err(eyre!("Failed to recover identity secret: {err}")),
+            Err(err) => Err(format!("Failed to recover identity secret: {err}").into()),
         }
     }
 }
@@ -246,9 +231,9 @@ fn main() -> Result<()> {
     println!("Initializing RLN instance...");
     print!("\x1B[2J\x1B[1;1H");
     let mut rln_system = RLNSystem::new()?;
-    let rln_epoch = hash_to_field(b"epoch");
-    let rln_identifier = hash_to_field(b"rln-identifier");
-    let external_nullifier = poseidon_hash(&[rln_epoch, rln_identifier]);
+    let rln_epoch = hash_to_field_le(b"epoch")?;
+    let rln_identifier = hash_to_field_le(b"rln-identifier")?;
+    let external_nullifier = poseidon_hash(&[rln_epoch, rln_identifier]).unwrap();
     println!("RLN Relay Example:");
     println!("Message Limit: {MESSAGE_LIMIT}");
     println!("----------------------------------");
@@ -275,15 +260,15 @@ fn main() -> Result<()> {
                     message_id,
                     signal,
                 } => {
-                    match rln_system.generate_proof(
+                    match rln_system.generate_and_verify_proof(
                         user_index,
                         message_id,
                         &signal,
                         external_nullifier,
                     ) {
-                        Ok(proof) => {
-                            if let Err(err) = rln_system.verify_proof(proof, &signal) {
-                                println!("Verification error: {err}");
+                        Ok(proof_values) => {
+                            if let Err(err) = rln_system.check_nullifier(proof_values) {
+                                println!("Check nullifier error: {err}");
                             };
                         }
                         Err(err) => {

rln-cli/src/examples/stateless.rs

@@ -1,23 +1,20 @@
 #![cfg(feature = "stateless")]
+
 use std::{
     collections::HashMap,
-    io::{stdin, stdout, Cursor, Write},
+    io::{stdin, stdout, Write},
 };
 
 use clap::{Parser, Subcommand};
-use color_eyre::{eyre::eyre, Result};
-use rln::{
-    circuit::{Fr, TEST_TREE_HEIGHT},
-    hashers::{hash_to_field, poseidon_hash},
-    poseidon_tree::PoseidonTree,
-    protocol::{keygen, prepare_verify_input, rln_witness_from_values, serialize_witness},
-    public::RLN,
-    utils::{bytes_le_to_fr, fr_to_bytes_le},
+use rln::prelude::{
+    hash_to_field_le, keygen, poseidon_hash, recover_id_secret, Fr, IdSecret, OptimalMerkleTree,
+    PoseidonHash, RLNProofValues, RLNWitnessInput, ZerokitMerkleProof, ZerokitMerkleTree,
+    DEFAULT_TREE_DEPTH, RLN,
 };
-use zerokit_utils::ZerokitMerkleTree;
 
 const MESSAGE_LIMIT: u32 = 1;
 
+type Result<T> = std::result::Result<T, Box<dyn std::error::Error>>;
 type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
 
 #[derive(Parser)]
@@ -45,15 +42,15 @@ enum Commands {
 
 #[derive(Debug, Clone)]
 struct Identity {
-    identity_secret_hash: Fr,
+    identity_secret: IdSecret,
     id_commitment: Fr,
 }
 
 impl Identity {
     fn new() -> Self {
-        let (identity_secret_hash, id_commitment) = keygen();
+        let (identity_secret, id_commitment) = keygen().unwrap();
         Identity {
-            identity_secret_hash,
+            identity_secret,
             id_commitment,
         }
     }
@@ -61,8 +58,8 @@ impl Identity {
 
 struct RLNSystem {
     rln: RLN,
-    tree: PoseidonTree,
-    used_nullifiers: HashMap<[u8; 32], Vec<u8>>,
+    tree: OptimalMerkleTree<PoseidonHash>,
+    used_nullifiers: HashMap<Fr, RLNProofValues>,
     local_identities: HashMap<usize, Identity>,
 }
 
@@ -70,11 +67,12 @@ impl RLNSystem {
     fn new() -> Result<Self> {
         let rln = RLN::new()?;
         let default_leaf = Fr::from(0);
-        let tree = PoseidonTree::new(
-            TEST_TREE_HEIGHT,
+        let tree: OptimalMerkleTree<PoseidonHash> = OptimalMerkleTree::new(
+            DEFAULT_TREE_DEPTH,
             default_leaf,
-            ConfigOf::<PoseidonTree>::default(),
-        )?;
+            ConfigOf::<OptimalMerkleTree<PoseidonHash>>::default(),
+        )
+        .unwrap();
 
         Ok(RLNSystem {
             rln,
@@ -93,8 +91,8 @@ impl RLNSystem {
         println!("Registered users:");
         for (index, identity) in &self.local_identities {
             println!("User Index: {index}");
-            println!("+ Identity Secret Hash: {}", identity.identity_secret_hash);
-            println!("+ Identity Commitment: {}", identity.id_commitment);
+            println!("+ Identity secret: {}", *identity.identity_secret);
+            println!("+ Identity commitment: {}", identity.id_commitment);
             println!();
         }
     }
@@ -103,137 +101,117 @@ impl RLNSystem {
         let index = self.tree.leaves_set();
         let identity = Identity::new();
 
-        let rate_commitment = poseidon_hash(&[identity.id_commitment, Fr::from(MESSAGE_LIMIT)]);
+        let rate_commitment =
+            poseidon_hash(&[identity.id_commitment, Fr::from(MESSAGE_LIMIT)]).unwrap();
         self.tree.update_next(rate_commitment)?;
 
         println!("Registered User Index: {index}");
-        println!("+ Identity secret hash: {}", identity.identity_secret_hash);
+        println!("+ Identity secret: {}", *identity.identity_secret);
         println!("+ Identity commitment: {}", identity.id_commitment);
 
         self.local_identities.insert(index, identity);
         Ok(index)
     }
 
-    fn generate_proof(
+    fn generate_and_verify_proof(
         &mut self,
         user_index: usize,
         message_id: u32,
         signal: &str,
         external_nullifier: Fr,
-    ) -> Result<Vec<u8>> {
+    ) -> Result<RLNProofValues> {
         let identity = match self.local_identities.get(&user_index) {
             Some(identity) => identity,
-            None => return Err(eyre!("user index {user_index} not found")),
+            None => return Err(format!("user index {user_index} not found").into()),
         };
 
         let merkle_proof = self.tree.proof(user_index)?;
-        let x = hash_to_field(signal.as_bytes());
+        let x = hash_to_field_le(signal.as_bytes())?;
 
-        let rln_witness = rln_witness_from_values(
-            identity.identity_secret_hash,
-            &merkle_proof,
-            x,
-            external_nullifier,
+        let witness = RLNWitnessInput::new(
+            identity.identity_secret.clone(),
             Fr::from(MESSAGE_LIMIT),
             Fr::from(message_id),
+            merkle_proof.get_path_elements(),
+            merkle_proof.get_path_index(),
+            x,
+            external_nullifier,
         )?;
 
-        let serialized = serialize_witness(&rln_witness)?;
-        let mut input_buffer = Cursor::new(serialized);
-        let mut output_buffer = Cursor::new(Vec::new());
-
-        self.rln
-            .generate_rln_proof_with_witness(&mut input_buffer, &mut output_buffer)?;
+        let (proof, proof_values) = self.rln.generate_rln_proof(&witness)?;
 
         println!("Proof generated successfully:");
         println!("+ User Index: {user_index}");
         println!("+ Message ID: {message_id}");
         println!("+ Signal: {signal}");
 
-        Ok(output_buffer.into_inner())
+        let tree_root = self.tree.root();
+
+        let verified = self
+            .rln
+            .verify_with_roots(&proof, &proof_values, &x, &[tree_root])?;
+        if verified {
+            println!("Proof verified successfully");
         }
 
-    fn verify_proof(&mut self, proof_data: Vec<u8>, signal: &str) -> Result<()> {
-        let proof_with_signal = prepare_verify_input(proof_data.clone(), signal.as_bytes());
-        let mut input_buffer = Cursor::new(proof_with_signal);
+        Ok(proof_values)
+    }
 
-        let root = self.tree.root();
-        let roots_serialized = fr_to_bytes_le(&root);
-        let mut roots_buffer = Cursor::new(roots_serialized);
+    fn check_nullifier(&mut self, proof_values: RLNProofValues) -> Result<()> {
+        let tree_root = self.tree.root();
 
-        match self
-            .rln
-            .verify_with_roots(&mut input_buffer, &mut roots_buffer)
-        {
-            Ok(true) => {
-                let nullifier = &proof_data[256..288];
-                let nullifier_key: [u8; 32] = nullifier.try_into()?;
-
-                if let Some(previous_proof) = self.used_nullifiers.get(&nullifier_key) {
-                    self.handle_duplicate_message_id(previous_proof.clone(), proof_data)?;
+        if proof_values.root != tree_root {
+            println!("Check nullifier failed: invalid root");
             return Ok(());
         }
-                self.used_nullifiers.insert(nullifier_key, proof_data);
+
+        if let Some(&previous_proof_values) = self.used_nullifiers.get(&proof_values.nullifier) {
+            self.handle_duplicate_message_id(previous_proof_values, proof_values)?;
+            return Ok(());
+        }
+
+        self.used_nullifiers
+            .insert(proof_values.nullifier, proof_values);
         println!("Message verified and accepted");
-            }
-            Ok(false) => {
-                println!("Verification failed: message_id must be unique within the epoch and satisfy 0 <= message_id < MESSAGE_LIMIT: {MESSAGE_LIMIT}");
-            }
-            Err(err) => return Err(err.into()),
-        }
         Ok(())
     }
 
     fn handle_duplicate_message_id(
         &mut self,
-        previous_proof: Vec<u8>,
-        current_proof: Vec<u8>,
+        previous_proof_values: RLNProofValues,
+        current_proof_values: RLNProofValues,
     ) -> Result<()> {
-        let x = &current_proof[192..224];
-        let y = &current_proof[224..256];
-
-        let prev_x = &previous_proof[192..224];
-        let prev_y = &previous_proof[224..256];
-        if x == prev_x && y == prev_y {
-            return Err(eyre!("this exact message and signal has already been sent"));
+        if previous_proof_values.x == current_proof_values.x
+            && previous_proof_values.y == current_proof_values.y
+        {
+            return Err("this exact message and signal has already been sent".into());
         }
 
-        let mut proof1 = Cursor::new(previous_proof);
-        let mut proof2 = Cursor::new(current_proof);
-        let mut output = Cursor::new(Vec::new());
-
-        match self
-            .rln
-            .recover_id_secret(&mut proof1, &mut proof2, &mut output)
-        {
-            Ok(_) => {
-                let output_data = output.into_inner();
-                let (leaked_identity_secret_hash, _) = bytes_le_to_fr(&output_data);
-
+        match recover_id_secret(&previous_proof_values, &current_proof_values) {
+            Ok(leaked_identity_secret) => {
                 if let Some((user_index, identity)) = self
                     .local_identities
                     .iter()
-                    .find(|(_, identity)| {
-                        identity.identity_secret_hash == leaked_identity_secret_hash
-                    })
+                    .find(|(_, identity)| identity.identity_secret == leaked_identity_secret)
                     .map(|(index, identity)| (*index, identity))
                 {
-                    let real_identity_secret_hash = identity.identity_secret_hash;
-                    if leaked_identity_secret_hash != real_identity_secret_hash {
-                        Err(eyre!("identity secret hash mismatch {leaked_identity_secret_hash} != {real_identity_secret_hash}"))
+                    let real_identity_secret = identity.identity_secret.clone();
+                    if leaked_identity_secret != real_identity_secret {
+                        Err("Identity secret mismatch: leaked_identity_secret != real_identity_secret".into())
                     } else {
-                        println!("DUPLICATE message ID detected! Reveal identity secret hash: {leaked_identity_secret_hash}");
+                        println!(
+                            "DUPLICATE message ID detected! Reveal identity secret: {}",
+                            *leaked_identity_secret
+                        );
                         self.local_identities.remove(&user_index);
                         println!("User index {user_index} has been SLASHED");
                         Ok(())
                     }
                 } else {
-                    Err(eyre!(
-                        "user identity secret hash {leaked_identity_secret_hash} not found"
-                    ))
+                    Err("user identity secret ******** not found".into())
                 }
             }
-            Err(err) => Err(eyre!("Failed to recover identity secret: {err}")),
+            Err(err) => Err(format!("Failed to recover identity secret: {err}").into()),
         }
     }
 }
@@ -242,9 +220,9 @@ fn main() -> Result<()> {
     println!("Initializing RLN instance...");
     print!("\x1B[2J\x1B[1;1H");
     let mut rln_system = RLNSystem::new()?;
-    let rln_epoch = hash_to_field(b"epoch");
-    let rln_identifier = hash_to_field(b"rln-identifier");
-    let external_nullifier = poseidon_hash(&[rln_epoch, rln_identifier]);
+    let rln_epoch = hash_to_field_le(b"epoch")?;
+    let rln_identifier = hash_to_field_le(b"rln-identifier")?;
+    let external_nullifier = poseidon_hash(&[rln_epoch, rln_identifier]).unwrap();
     println!("RLN Stateless Relay Example:");
     println!("Message Limit: {MESSAGE_LIMIT}");
     println!("----------------------------------");
@@ -272,15 +250,15 @@ fn main() -> Result<()> {
                     message_id,
                     signal,
                 } => {
-                    match rln_system.generate_proof(
+                    match rln_system.generate_and_verify_proof(
                         user_index,
                         message_id,
                         &signal,
                         external_nullifier,
                     ) {
-                        Ok(proof) => {
-                            if let Err(err) = rln_system.verify_proof(proof, &signal) {
-                                println!("Verification error: {err}");
+                        Ok(proof_values) => {
+                            if let Err(err) = rln_system.check_nullifier(proof_values) {
+                                println!("Check nullifier error: {err}");
                             };
                         }
                         Err(err) => {

rln-cli/src/main.rs

@@ -1,202 +0,0 @@
-use std::{
-    fs::File,
-    io::{Cursor, Read},
-    path::Path,
-};
-
-use clap::Parser;
-use color_eyre::{eyre::Report, Result};
-use commands::Commands;
-use config::{Config, InnerConfig};
-use rln::{
-    public::RLN,
-    utils::{bytes_le_to_fr, bytes_le_to_vec_fr},
-};
-use serde_json::json;
-use state::State;
-
-mod commands;
-mod config;
-mod state;
-
-#[derive(Parser)]
-#[command(author, version, about, long_about = None)]
-struct Cli {
-    #[command(subcommand)]
-    command: Option<Commands>,
-}
-
-fn main() -> Result<()> {
-    let cli = Cli::parse();
-
-    let mut state = match &cli.command {
-        Some(Commands::New { .. }) | Some(Commands::NewWithParams { .. }) => State::default(),
-        _ => State::load_state()?,
-    };
-
-    match cli.command {
-        Some(Commands::New { tree_height }) => {
-            let config = Config::load_config()?;
-            state.rln = if let Some(InnerConfig { tree_height, .. }) = config.inner {
-                println!("Initializing RLN with custom config");
-                Some(RLN::new(tree_height, Cursor::new(config.as_bytes()))?)
-            } else {
-                println!("Initializing RLN with default config");
-                Some(RLN::new(tree_height, Cursor::new(json!({}).to_string()))?)
-            };
-            Ok(())
-        }
-        Some(Commands::NewWithParams {
-            tree_height,
-            resources_path,
-        }) => {
-            let mut resources: Vec<Vec<u8>> = Vec::new();
-            #[cfg(feature = "arkzkey")]
-            let filenames = ["rln_final.arkzkey", "graph.bin"];
-            #[cfg(not(feature = "arkzkey"))]
-            let filenames = ["rln_final.zkey", "graph.bin"];
-            for filename in filenames {
-                let fullpath = resources_path.join(Path::new(filename));
-                let mut file = File::open(&fullpath)?;
-                let metadata = std::fs::metadata(&fullpath)?;
-                let mut output_buffer = vec![0; metadata.len() as usize];
-                file.read_exact(&mut output_buffer)?;
-                resources.push(output_buffer);
-            }
-            let config = Config::load_config()?;
-            if let Some(InnerConfig {
-                tree_height,
-                tree_config,
-            }) = config.inner
-            {
-                println!("Initializing RLN with custom config");
-                state.rln = Some(RLN::new_with_params(
-                    tree_height,
-                    resources[0].clone(),
-                    resources[1].clone(),
-                    Cursor::new(tree_config.to_string().as_bytes()),
-                )?)
-            } else {
-                println!("Initializing RLN with default config");
-                state.rln = Some(RLN::new_with_params(
-                    tree_height,
-                    resources[0].clone(),
-                    resources[1].clone(),
-                    Cursor::new(json!({}).to_string()),
-                )?)
-            };
-            Ok(())
-        }
-        Some(Commands::SetTree { tree_height }) => {
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .set_tree(tree_height)?;
-            Ok(())
-        }
-        Some(Commands::SetLeaf { index, input }) => {
-            let input_data = File::open(input)?;
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .set_leaf(index, input_data)?;
-            Ok(())
-        }
-        Some(Commands::SetMultipleLeaves { index, input }) => {
-            let input_data = File::open(input)?;
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .set_leaves_from(index, input_data)?;
-            Ok(())
-        }
-        Some(Commands::ResetMultipleLeaves { input }) => {
-            let input_data = File::open(input)?;
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .init_tree_with_leaves(input_data)?;
-            Ok(())
-        }
-        Some(Commands::SetNextLeaf { input }) => {
-            let input_data = File::open(input)?;
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .set_next_leaf(input_data)?;
-            Ok(())
-        }
-        Some(Commands::DeleteLeaf { index }) => {
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .delete_leaf(index)?;
-            Ok(())
-        }
-        Some(Commands::Prove { input }) => {
-            let input_data = File::open(input)?;
-            let mut output_buffer = Cursor::new(Vec::<u8>::new());
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .prove(input_data, &mut output_buffer)?;
-            let proof = output_buffer.into_inner();
-            println!("proof: {:?}", proof);
-            Ok(())
-        }
-        Some(Commands::Verify { input }) => {
-            let input_data = File::open(input)?;
-            let verified = state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .verify(input_data)?;
-            println!("verified: {:?}", verified);
-            Ok(())
-        }
-        Some(Commands::GenerateProof { input }) => {
-            let input_data = File::open(input)?;
-            let mut output_buffer = Cursor::new(Vec::<u8>::new());
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .generate_rln_proof(input_data, &mut output_buffer)?;
-            let proof = output_buffer.into_inner();
-            println!("proof: {:?}", proof);
-            Ok(())
-        }
-        Some(Commands::VerifyWithRoots { input, roots }) => {
-            let input_data = File::open(input)?;
-            let roots_data = File::open(roots)?;
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .verify_with_roots(input_data, roots_data)?;
-            Ok(())
-        }
-        Some(Commands::GetRoot) => {
-            let mut output_buffer = Cursor::new(Vec::<u8>::new());
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .get_root(&mut output_buffer)
-                .unwrap();
-            let (root, _) = bytes_le_to_fr(&output_buffer.into_inner());
-            println!("root: {root}");
-            Ok(())
-        }
-        Some(Commands::GetProof { index }) => {
-            let mut output_buffer = Cursor::new(Vec::<u8>::new());
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .get_proof(index, &mut output_buffer)?;
-            let output_buffer_inner = output_buffer.into_inner();
-            let (path_elements, _) = bytes_le_to_vec_fr(&output_buffer_inner)?;
-            for (index, element) in path_elements.iter().enumerate() {
-                println!("path element {}: {}", index, element);
-            }
-            Ok(())
-        }
-        None => Ok(()),
-    }
-}

rln-cli/src/state.rs

@@ -1,23 +0,0 @@
-use std::io::Cursor;
-
-use color_eyre::Result;
-use rln::public::RLN;
-
-use crate::config::{Config, InnerConfig};
-
-#[derive(Default)]
-pub(crate) struct State {
-    pub rln: Option<RLN>,
-}
-
-impl State {
-    pub(crate) fn load_state() -> Result<State> {
-        let config = Config::load_config()?;
-        let rln = if let Some(InnerConfig { tree_height, .. }) = config.inner {
-            Some(RLN::new(tree_height, Cursor::new(config.as_bytes()))?)
-        } else {
-            None
-        };
-        Ok(State { rln })
-    }
-}

rln-wasm/.gitignore

@@ -1,6 +1,22 @@
+# Common files to ignore in Rust projects
+.DS_Store
+.idea
+*.log
+tmp/
+
+# Generated by Cargo will have compiled files and executables
 /target
+
+# Generated by rln-wasm
+/pkg
+/examples/node_modules
+/examples/package-lock.json
+
+# Generated by Nix
+result
+
+# These are backup files generated by rustfmt
 **/*.rs.bk
-Cargo.lock
-bin/
-pkg/
-wasm-pack.log
+
+# MSVC Windows builds of rustc generate these, which store debugging information
+*.pdb

rln-wasm/Cargo.toml

@@ -1,39 +1,53 @@
 [package]
 name = "rln-wasm"
-version = "0.1.0"
+version = "1.0.0"
 edition = "2021"
-license = "MIT or Apache2"
+license = "MIT OR Apache-2.0"
 
 [lib]
 crate-type = ["cdylib", "rlib"]
-required-features = ["stateless"]
 
 [dependencies]
-rln = { path = "../rln", default-features = false }
-num-bigint = { version = "0.4.6", default-features = false, features = [
-    "rand",
-    "serde",
+rln = { path = "../rln", version = "1.0.0", default-features = false, features = [
+    "stateless",
 ] }
-wasm-bindgen = "0.2.100"
+zerokit_utils = { path = "../utils", version = "1.0.0", default-features = false }
+num-bigint = { version = "0.4.6", default-features = false }
+js-sys = "0.3.83"
+wasm-bindgen = "0.2.106"
 serde-wasm-bindgen = "0.6.5"
-js-sys = "0.3.77"
-serde_json = "1.0"
+serde = "1.0.228"
+wasm-bindgen-rayon = { version = "1.3.0", features = [
+    "no-bundler",
+], optional = true }
+ark-relations = { version = "0.5.1", features = ["std"] }
+ark-groth16 = { version = "0.5.0", default-features = false }
+rand = "0.8.5"
 
-# The `console_error_panic_xhook` crate provides better debugging of panics by
+# The `console_error_panic_hook` crate provides better debugging of panics by
 # logging them with `console.error`. This is great for development, but requires
 # all the `std::fmt` and `std::panicking` infrastructure, so isn't great for
 # code size when deploying.
 console_error_panic_hook = { version = "0.1.7", optional = true }
-zerokit_utils = { path = "../utils" }
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]
-getrandom = { version = "0.2.15", features = ["js"] }
+getrandom = { version = "0.2.16", features = ["js"] }
 
 [dev-dependencies]
-wasm-bindgen-test = "0.3.50"
-wasm-bindgen-futures = "0.4.50"
+serde_json = "1.0.145"
+wasm-bindgen-test = "0.3.56"
+wasm-bindgen-futures = "0.4.56"
+ark-std = { version = "0.5.0", default-features = false }
+
+[dev-dependencies.web-sys]
+version = "0.3.83"
+features = ["Window", "Navigator"]
 
 [features]
-default = ["console_error_panic_hook"]
-stateless = ["rln/stateless"]
-arkzkey = ["rln/arkzkey"]
+default = []
+utils = []
+panic_hook = ["console_error_panic_hook"]
+parallel = ["rln/parallel", "wasm-bindgen-rayon", "ark-groth16/parallel"]
+
+[package.metadata.docs.rs]
+all-features = true

rln-wasm/Makefile.toml

@@ -1,24 +1,72 @@
 [tasks.build]
 clear = true
-dependencies = ["pack_build", "pack_rename"]
+dependencies = ["pack_build", "pack_rename", "pack_add_keywords"]
 
-[tasks.build_arkzkey]
+[tasks.build_parallel]
 clear = true
-dependencies = ["pack_build_arkzkey", "pack_rename"]
+dependencies = [
+    "pack_build_parallel",
+    "pack_rename_parallel",
+    "pack_add_keywords",
+]
+
+[tasks.build_utils]
+clear = true
+dependencies = ["pack_build_utils", "pack_rename_utils", "pack_add_keywords"]
 
 [tasks.pack_build]
 command = "wasm-pack"
 args = ["build", "--release", "--target", "web", "--scope", "waku"]
-env = { "RUSTFLAGS" = "--cfg feature=\"stateless\"" }
-
-[tasks.pack_build_arkzkey]
-command = "wasm-pack"
-args = ["build", "--release", "--target", "web", "--scope", "waku"]
-env = { "RUSTFLAGS" = "--cfg feature=\"stateless\" --cfg feature=\"arkzkey\"" }
 
 [tasks.pack_rename]
 script = "sed -i.bak 's/rln-wasm/zerokit-rln-wasm/g' pkg/package.json && rm pkg/package.json.bak"
 
+[tasks.pack_build_parallel]
+command = "env"
+args = [
+    "CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_RUSTFLAGS=-C target-feature=+atomics,+bulk-memory,+mutable-globals -C link-arg=--shared-memory -C link-arg=--max-memory=1073741824 -C link-arg=--import-memory -C link-arg=--export=__wasm_init_tls -C link-arg=--export=__tls_size -C link-arg=--export=__tls_align -C link-arg=--export=__tls_base",
+    "rustup",
+    "run",
+    "nightly",
+    "wasm-pack",
+    "build",
+    "--release",
+    "--target",
+    "web",
+    "--scope",
+    "waku",
+    "--features",
+    "parallel",
+    "-Z",
+    "build-std=panic_abort,std",
+]
+
+[tasks.pack_rename_parallel]
+script = "sed -i.bak 's/rln-wasm/zerokit-rln-wasm-parallel/g' pkg/package.json && rm pkg/package.json.bak"
+
+[tasks.pack_build_utils]
+command = "wasm-pack"
+args = [
+    "build",
+    "--release",
+    "--target",
+    "web",
+    "--scope",
+    "waku",
+    "--no-default-features",
+    "--features",
+    "utils",
+]
+
+[tasks.pack_rename_utils]
+script = "sed -i.bak 's/rln-wasm/zerokit-rln-wasm-utils/g' pkg/package.json && rm pkg/package.json.bak"
+
+[tasks.pack_add_keywords]
+script = """
+  jq '. + {keywords: ["zerokit", "rln", "wasm"]}' pkg/package.json > pkg/package.json.tmp && \
+  mv pkg/package.json.tmp pkg/package.json
+"""
+
 [tasks.test]
 command = "wasm-pack"
 args = [
@@ -30,9 +78,46 @@ args = [
     "--",
     "--nocapture",
 ]
-env = { "RUSTFLAGS" = "--cfg feature=\"stateless\"" }
+dependencies = ["build"]
 
-[tasks.test_arkzkey]
+[tasks.test_browser]
+command = "wasm-pack"
+args = [
+    "test",
+    "--release",
+    "--chrome",
+    "--headless",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build"]
+
+[tasks.test_parallel]
+command = "env"
+args = [
+    "CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_RUSTFLAGS=-C target-feature=+atomics,+bulk-memory,+mutable-globals -C link-arg=--shared-memory -C link-arg=--max-memory=1073741824 -C link-arg=--import-memory -C link-arg=--export=__wasm_init_tls -C link-arg=--export=__tls_size -C link-arg=--export=__tls_align -C link-arg=--export=__tls_base",
+    "rustup",
+    "run",
+    "nightly",
+    "wasm-pack",
+    "test",
+    "--release",
+    "--chrome",
+    "--headless",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--features",
+    "parallel",
+    "-Z",
+    "build-std=panic_abort,std",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build_parallel"]
+
+[tasks.test_utils]
 command = "wasm-pack"
 args = [
     "test",
@@ -40,19 +125,13 @@ args = [
     "--node",
     "--target",
     "wasm32-unknown-unknown",
+    "--no-default-features",
+    "--features",
+    "utils",
     "--",
     "--nocapture",
 ]
-env = { "RUSTFLAGS" = "--cfg feature=\"stateless\" --cfg feature=\"arkzkey\"" }
-dependencies = ["build_arkzkey"]
+dependencies = ["build_utils"]
 
 [tasks.bench]
 disabled = true
-
-[tasks.login]
-command = "wasm-pack"
-args = ["login"]
-
-[tasks.publish]
-command = "wasm-pack"
-args = ["publish", "--access", "public", "--target", "web"]

rln-wasm/README.md

@@ -1,55 +1,119 @@
 # RLN for WASM
 
-This library is used in [waku-org/js-rln](https://github.com/waku-org/js-rln/)
+[![npm version](https://badge.fury.io/js/@waku%2Fzerokit-rln-wasm.svg)](https://badge.fury.io/js/@waku%2Fzerokit-rln-wasm)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 
-> **Note**: This project requires `wasm-pack` for compiling Rust to WebAssembly and `cargo-make` for running the build commands. Make sure both are installed before proceeding.
+The Zerokit RLN WASM Module provides WebAssembly bindings for working with
+Rate-Limiting Nullifier [RLN](https://rfc.vac.dev/vac/raw/rln-v2) zkSNARK proofs and primitives.
+This module is used by [waku-org/js-rln](https://github.com/waku-org/js-rln/) to enable
+RLN functionality in JavaScript/TypeScript applications.
 
-Install `wasm-pack`:
+## Install Dependencies
 
-```bash
-curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
-```
+> [!NOTE]
+> This project requires the following tools:
+>
+> - `wasm-pack` (v0.13.1) - for compiling Rust to WebAssembly
+> - `cargo-make` - for running build commands
+> - `nvm` - to install and manage Node.js (v22.14.0+)
 
-Install `cargo-make`
-
-```bash
-cargo install cargo-make
-```
-
-Or install everything needed for `zerokit` at the root of the repository:
+### Quick Install
 
 ```bash
 make installdeps
 ```
 
-## Building the library
+### Manual Installation
 
-First, navigate to the rln-wasm directory:
+```bash
+# Install wasm-pack
+cargo install wasm-pack --version=0.13.1
+
+# Install cargo-make
+cargo install cargo-make
+
+# Install Node.js via nvm
+nvm install 22.14.0
+nvm use 22.14.0
+nvm alias default 22.14.0
+```
+
+## Building the Library
+
+Navigate to the rln-wasm directory:
 
 ```bash
 cd rln-wasm
 ```
 
-Compile zerokit for `wasm32-unknown-unknown`:
+Build commands:
 
 ```bash
-cargo make build
+cargo make build          # Default → @waku/zerokit-rln-wasm
+cargo make build_parallel # Parallel → @waku/zerokit-rln-wasm-parallel (requires nightly Rust)
+cargo make build_utils    # Utils only → @waku/zerokit-rln-wasm-utils
 ```
 
-Or compile with the **arkzkey** feature enabled
+All packages output to `pkg/` directory.
+
+## Running Tests and Benchmarks
 
 ```bash
-cargo make build_arkzkey
+cargo make test           # Standard tests
+cargo make test_browser   # Browser headless mode
+cargo make test_utils     # Utils-only tests
+cargo make test_parallel  # Parallel tests
 ```
 
-## Running tests and benchmarks
+## Examples
 
-```bash
-cargo make test
+See [Node example](./examples/index.js) and [README](./examples/Readme.md) for proof generation, verification, and slashing.
+
+## Parallel Computation
+
+Enables multi-threaded browser execution using `wasm-bindgen-rayon`.
+
+> [!NOTE]
+>
+> - Parallel support is not enabled by default due to WebAssembly and browser limitations.
+> - Requires `nightly` Rust: `rustup install nightly`
+> - Browser-only (not compatible with Node.js)
+> - Requires HTTP headers for `SharedArrayBuffer`:
+>   - `Cross-Origin-Opener-Policy: same-origin`
+>   - `Cross-Origin-Embedder-Policy: require-corp`
+
+### Usage
+
+Direct usage (modern browsers with WebAssembly threads support):
+
+```js
+import * as wasmPkg from '@waku/zerokit-rln-wasm-parallel';
+
+await wasmPkg.default();
+await wasmPkg.initThreadPool(navigator.hardwareConcurrency);
+wasmPkg.nowCallAnyExportedFuncs();
 ```
 
-Or test with the **arkzkey** feature enabled
+### Feature Detection for Older Browsers
 
-```bash
-cargo make test_arkzkey
+If you're targeting [older browser versions that didn't support WebAssembly threads yet](https://webassembly.org/roadmap/), you'll want to use both builds - the parallel version for modern browsers and the default version as a fallback. Use feature detection to choose the appropriate build on the JavaScript side.
+
+You can use the [wasm-feature-detect](https://github.com/GoogleChromeLabs/wasm-feature-detect) library for this purpose:
+
+```js
+import { threads } from 'wasm-feature-detect';
+
+let wasmPkg;
+
+if (await threads()) {
+  wasmPkg = await import('@waku/zerokit-rln-wasm-parallel');
+  await wasmPkg.default();
+  await wasmPkg.initThreadPool(navigator.hardwareConcurrency);
+} else {
+  wasmPkg = await import('@waku/zerokit-rln-wasm');
+  await wasmPkg.default();
+}
+
+wasmPkg.nowCallAnyExportedFuncs();
 ```

rln-wasm/examples/README.md

@@ -0,0 +1,22 @@
+# RLN WASM Node Examples
+
+This example demonstrates how to use the RLN WASM package in a Node.js environment.
+
+## Build the @waku/zerokit-rln-wasm package at the root of rln-wasm module
+
+```bash
+cargo make build
+```
+
+## Move into this directory and install dependencies
+
+```bash
+cd examples
+npm install
+```
+
+## Run
+
+```bash
+npm start
+```

rln-wasm/examples/index.js

@@ -0,0 +1,484 @@
+import { readFileSync } from "fs";
+import { fileURLToPath } from "url";
+import { dirname, join } from "path";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = dirname(__filename);
+
+function debugUint8Array(uint8Array) {
+  return Array.from(uint8Array, (byte) =>
+    byte.toString(16).padStart(2, "0")
+  ).join(", ");
+}
+
+async function calculateWitness(circomPath, inputs, witnessCalculatorFile) {
+  const wasmFile = readFileSync(circomPath);
+  const wasmFileBuffer = wasmFile.buffer.slice(
+    wasmFile.byteOffset,
+    wasmFile.byteOffset + wasmFile.byteLength
+  );
+  const witnessCalculator = await witnessCalculatorFile(wasmFileBuffer);
+  const calculatedWitness = await witnessCalculator.calculateWitness(
+    inputs,
+    false
+  );
+  return calculatedWitness;
+}
+
+async function main() {
+  const rlnWasm = await import("../pkg/rln_wasm.js");
+  const wasmPath = join(__dirname, "../pkg/rln_wasm_bg.wasm");
+  const wasmBytes = readFileSync(wasmPath);
+  rlnWasm.initSync({ module: wasmBytes });
+
+  const zkeyPath = join(
+    __dirname,
+    "../../rln/resources/tree_depth_20/rln_final.arkzkey"
+  );
+  const circomPath = join(
+    __dirname,
+    "../../rln/resources/tree_depth_20/rln.wasm"
+  );
+  const witnessCalculatorPath = join(
+    __dirname,
+    "../resources/witness_calculator.js"
+  );
+  const { builder: witnessCalculatorFile } = await import(
+    witnessCalculatorPath
+  );
+
+  console.log("Creating RLN instance");
+  const zkeyData = readFileSync(zkeyPath);
+  let rlnInstance;
+  try {
+    rlnInstance = new rlnWasm.WasmRLN(new Uint8Array(zkeyData));
+  } catch (error) {
+    console.error("Initial RLN instance creation error:", error);
+    return;
+  }
+  console.log("RLN instance created successfully");
+
+  console.log("\nGenerating identity keys");
+  let identity;
+  try {
+    identity = rlnWasm.Identity.generate();
+  } catch (error) {
+    console.error("Key generation error:", error);
+    return;
+  }
+  const identitySecret = identity.getSecretHash();
+  const idCommitment = identity.getCommitment();
+  console.log("Identity generated");
+  console.log("  - identity_secret = " + identitySecret.debug());
+  console.log("  - id_commitment = " + idCommitment.debug());
+
+  console.log("\nCreating message limit");
+  const userMessageLimit = rlnWasm.WasmFr.fromUint(1);
+  console.log("  - user_message_limit = " + userMessageLimit.debug());
+
+  console.log("\nComputing rate commitment");
+  let rateCommitment;
+  try {
+    rateCommitment = rlnWasm.Hasher.poseidonHashPair(
+      idCommitment,
+      userMessageLimit
+    );
+  } catch (error) {
+    console.error("Rate commitment hash error:", error);
+    return;
+  }
+  console.log("  - rate_commitment = " + rateCommitment.debug());
+
+  console.log("\nWasmFr serialization: WasmFr <-> bytes");
+  const serRateCommitment = rateCommitment.toBytesLE();
+  console.log(
+    "  - serialized rate_commitment = [" +
+      debugUint8Array(serRateCommitment) +
+      "]"
+  );
+
+  let deserRateCommitment;
+  try {
+    deserRateCommitment = rlnWasm.WasmFr.fromBytesLE(serRateCommitment);
+  } catch (error) {
+    console.error("Rate commitment deserialization error:", error);
+    return;
+  }
+  console.log(
+    "  - deserialized rate_commitment = " + deserRateCommitment.debug()
+  );
+
+  console.log("\nIdentity serialization: Identity <-> bytes");
+  const serIdentity = identity.toBytesLE();
+  console.log(
+    "  - serialized identity = [" + debugUint8Array(serIdentity) + "]"
+  );
+
+  let deserIdentity;
+  try {
+    deserIdentity = rlnWasm.Identity.fromBytesLE(serIdentity);
+  } catch (error) {
+    console.error("Identity deserialization error:", error);
+    return;
+  }
+  const deserIdentitySecret = deserIdentity.getSecretHash();
+  const deserIdCommitment = deserIdentity.getCommitment();
+  console.log(
+    "  - deserialized identity = [" +
+      deserIdentitySecret.debug() +
+      ", " +
+      deserIdCommitment.debug() +
+      "]"
+  );
+
+  console.log("\nBuilding Merkle path for stateless mode");
+  const treeDepth = 20;
+  const defaultLeaf = rlnWasm.WasmFr.zero();
+
+  const defaultHashes = [];
+  try {
+    defaultHashes[0] = rlnWasm.Hasher.poseidonHashPair(
+      defaultLeaf,
+      defaultLeaf
+    );
+    for (let i = 1; i < treeDepth - 1; i++) {
+      defaultHashes[i] = rlnWasm.Hasher.poseidonHashPair(
+        defaultHashes[i - 1],
+        defaultHashes[i - 1]
+      );
+    }
+  } catch (error) {
+    console.error("Poseidon hash error:", error);
+    return;
+  }
+
+  const pathElements = new rlnWasm.VecWasmFr();
+  pathElements.push(defaultLeaf);
+  for (let i = 1; i < treeDepth; i++) {
+    pathElements.push(defaultHashes[i - 1]);
+  }
+  const identityPathIndex = new Uint8Array(treeDepth);
+
+  console.log("\nVecWasmFr serialization: VecWasmFr <-> bytes");
+  const serPathElements = pathElements.toBytesLE();
+  console.log(
+    "  - serialized path_elements = [" + debugUint8Array(serPathElements) + "]"
+  );
+
+  let deserPathElements;
+  try {
+    deserPathElements = rlnWasm.VecWasmFr.fromBytesLE(serPathElements);
+  } catch (error) {
+    console.error("Path elements deserialization error:", error);
+    return;
+  }
+  console.log("  - deserialized path_elements = ", deserPathElements.debug());
+
+  console.log("\nUint8Array serialization: Uint8Array <-> bytes");
+  const serPathIndex = rlnWasm.Uint8ArrayUtils.toBytesLE(identityPathIndex);
+  console.log(
+    "  - serialized path_index = [" + debugUint8Array(serPathIndex) + "]"
+  );
+
+  let deserPathIndex;
+  try {
+    deserPathIndex = rlnWasm.Uint8ArrayUtils.fromBytesLE(serPathIndex);
+  } catch (error) {
+    console.error("Path index deserialization error:", error);
+    return;
+  }
+  console.log("  - deserialized path_index =", deserPathIndex);
+
+  console.log("\nComputing Merkle root for stateless mode");
+  console.log("  - computing root for index 0 with rate_commitment");
+
+  let computedRoot;
+  try {
+    computedRoot = rlnWasm.Hasher.poseidonHashPair(rateCommitment, defaultLeaf);
+    for (let i = 1; i < treeDepth; i++) {
+      computedRoot = rlnWasm.Hasher.poseidonHashPair(
+        computedRoot,
+        defaultHashes[i - 1]
+      );
+    }
+  } catch (error) {
+    console.error("Poseidon hash error:", error);
+    return;
+  }
+  console.log("  - computed_root = " + computedRoot.debug());
+
+  console.log("\nHashing signal");
+  const signal = new Uint8Array([
+    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0,
+  ]);
+  let x;
+  try {
+    x = rlnWasm.Hasher.hashToFieldLE(signal);
+  } catch (error) {
+    console.error("Hash signal error:", error);
+    return;
+  }
+  console.log("  - x = " + x.debug());
+
+  console.log("\nHashing epoch");
+  const epochStr = "test-epoch";
+  let epoch;
+  try {
+    epoch = rlnWasm.Hasher.hashToFieldLE(new TextEncoder().encode(epochStr));
+  } catch (error) {
+    console.error("Hash epoch error:", error);
+    return;
+  }
+  console.log("  - epoch = " + epoch.debug());
+
+  console.log("\nHashing RLN identifier");
+  const rlnIdStr = "test-rln-identifier";
+  let rlnIdentifier;
+  try {
+    rlnIdentifier = rlnWasm.Hasher.hashToFieldLE(
+      new TextEncoder().encode(rlnIdStr)
+    );
+  } catch (error) {
+    console.error("Hash RLN identifier error:", error);
+    return;
+  }
+  console.log("  - rln_identifier = " + rlnIdentifier.debug());
+
+  console.log("\nComputing Poseidon hash for external nullifier");
+  let externalNullifier;
+  try {
+    externalNullifier = rlnWasm.Hasher.poseidonHashPair(epoch, rlnIdentifier);
+  } catch (error) {
+    console.error("External nullifier hash error:", error);
+    return;
+  }
+  console.log("  - external_nullifier = " + externalNullifier.debug());
+
+  console.log("\nCreating message_id");
+  const messageId = rlnWasm.WasmFr.fromUint(0);
+  console.log("  - message_id = " + messageId.debug());
+
+  console.log("\nCreating RLN Witness");
+  const witness = new rlnWasm.WasmRLNWitnessInput(
+    identitySecret,
+    userMessageLimit,
+    messageId,
+    pathElements,
+    identityPathIndex,
+    x,
+    externalNullifier
+  );
+  console.log("RLN Witness created successfully");
+
+  console.log(
+    "\nWasmRLNWitnessInput serialization: WasmRLNWitnessInput <-> bytes"
+  );
+  let serWitness;
+  try {
+    serWitness = witness.toBytesLE();
+  } catch (error) {
+    console.error("Witness serialization error:", error);
+    return;
+  }
+  console.log(
+    "  - serialized witness = [" + debugUint8Array(serWitness) + " ]"
+  );
+
+  let deserWitness;
+  try {
+    deserWitness = rlnWasm.WasmRLNWitnessInput.fromBytesLE(serWitness);
+  } catch (error) {
+    console.error("Witness deserialization error:", error);
+    return;
+  }
+  console.log("  - witness deserialized successfully");
+
+  console.log("\nCalculating witness");
+  let witnessJson;
+  try {
+    witnessJson = witness.toBigIntJson();
+  } catch (error) {
+    console.error("Witness to BigInt JSON error:", error);
+    return;
+  }
+  const calculatedWitness = await calculateWitness(
+    circomPath,
+    witnessJson,
+    witnessCalculatorFile
+  );
+  console.log("Witness calculated successfully");
+
+  console.log("\nGenerating RLN Proof");
+  let rln_proof;
+  try {
+    rln_proof = rlnInstance.generateRLNProofWithWitness(
+      calculatedWitness,
+      witness
+    );
+  } catch (error) {
+    console.error("Proof generation error:", error);
+    return;
+  }
+  console.log("Proof generated successfully");
+
+  console.log("\nGetting proof values");
+  const proofValues = rln_proof.getValues();
+  console.log("  - y = " + proofValues.y.debug());
+  console.log("  - nullifier = " + proofValues.nullifier.debug());
+  console.log("  - root = " + proofValues.root.debug());
+  console.log("  - x = " + proofValues.x.debug());
+  console.log(
+    "  - external_nullifier = " + proofValues.externalNullifier.debug()
+  );
+
+  console.log("\nRLNProof serialization: RLNProof <-> bytes");
+  let serProof;
+  try {
+    serProof = rln_proof.toBytesLE();
+  } catch (error) {
+    console.error("Proof serialization error:", error);
+    return;
+  }
+  console.log("  - serialized proof = [" + debugUint8Array(serProof) + " ]");
+
+  let deserProof;
+  try {
+    deserProof = rlnWasm.WasmRLNProof.fromBytesLE(serProof);
+  } catch (error) {
+    console.error("Proof deserialization error:", error);
+    return;
+  }
+  console.log("  - proof deserialized successfully");
+
+  console.log("\nRLNProofValues serialization: RLNProofValues <-> bytes");
+  const serProofValues = proofValues.toBytesLE();
+  console.log(
+    "  - serialized proof_values = [" + debugUint8Array(serProofValues) + " ]"
+  );
+
+  let deserProofValues2;
+  try {
+    deserProofValues2 = rlnWasm.WasmRLNProofValues.fromBytesLE(serProofValues);
+  } catch (error) {
+    console.error("Proof values deserialization error:", error);
+    return;
+  }
+  console.log("  - proof_values deserialized successfully");
+  console.log(
+    "  - deserialized external_nullifier = " +
+      deserProofValues2.externalNullifier.debug()
+  );
+
+  console.log("\nVerifying Proof");
+  const roots = new rlnWasm.VecWasmFr();
+  roots.push(computedRoot);
+  let isValid;
+  try {
+    isValid = rlnInstance.verifyWithRoots(rln_proof, roots, x);
+  } catch (error) {
+    console.error("Proof verification error:", error);
+    return;
+  }
+  if (isValid) {
+    console.log("Proof verified successfully");
+  } else {
+    console.log("Proof verification failed");
+    return;
+  }
+
+  console.log(
+    "\nSimulating double-signaling attack (same epoch, different message)"
+  );
+
+  console.log("\nHashing second signal");
+  const signal2 = new Uint8Array([
+    11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+    0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
+  ]);
+  let x2;
+  try {
+    x2 = rlnWasm.Hasher.hashToFieldLE(signal2);
+  } catch (error) {
+    console.error("Hash second signal error:", error);
+    return;
+  }
+  console.log("  - x2 = " + x2.debug());
+
+  console.log("\nCreating second message with the same id");
+  const messageId2 = rlnWasm.WasmFr.fromUint(0);
+  console.log("  - message_id2 = " + messageId2.debug());
+
+  console.log("\nCreating second RLN Witness");
+  const witness2 = new rlnWasm.WasmRLNWitnessInput(
+    identitySecret,
+    userMessageLimit,
+    messageId2,
+    pathElements,
+    identityPathIndex,
+    x2,
+    externalNullifier
+  );
+  console.log("Second RLN Witness created successfully");
+
+  console.log("\nCalculating second witness");
+  let witnessJson2;
+  try {
+    witnessJson2 = witness2.toBigIntJson();
+  } catch (error) {
+    console.error("Second witness to BigInt JSON error:", error);
+    return;
+  }
+  const calculatedWitness2 = await calculateWitness(
+    circomPath,
+    witnessJson2,
+    witnessCalculatorFile
+  );
+  console.log("Second witness calculated successfully");
+
+  console.log("\nGenerating second RLN Proof");
+  let rln_proof2;
+  try {
+    rln_proof2 = rlnInstance.generateRLNProofWithWitness(
+      calculatedWitness2,
+      witness2
+    );
+  } catch (error) {
+    console.error("Second proof generation error:", error);
+    return;
+  }
+  console.log("Second proof generated successfully");
+
+  console.log("\nVerifying second proof");
+  let isValid2;
+  try {
+    isValid2 = rlnInstance.verifyWithRoots(rln_proof2, roots, x2);
+  } catch (error) {
+    console.error("Proof verification error:", error);
+    return;
+  }
+  if (isValid2) {
+    console.log("Second proof verified successfully");
+
+    console.log("\nRecovering identity secret");
+    const proofValues1 = rln_proof.getValues();
+    const proofValues2 = rln_proof2.getValues();
+    let recoveredSecret;
+    try {
+      recoveredSecret = rlnWasm.WasmRLNProofValues.recoverIdSecret(
+        proofValues1,
+        proofValues2
+      );
+    } catch (error) {
+      console.error("Identity recovery error:", error);
+      return;
+    }
+    console.log("  - recovered_secret = " + recoveredSecret.debug());
+    console.log("  - original_secret  = " + identitySecret.debug());
+    console.log("Slashing successful: Identity is recovered!");
+  } else {
+    console.log("Second proof verification failed");
+  }
+}
+
+main().catch(console.error);

rln-wasm/examples/package.json

@@ -0,0 +1,13 @@
+{
+  "name": "rln-wasm-node-example",
+  "version": "1.0.0",
+  "description": "Node.js example for RLN WASM",
+  "type": "module",
+  "main": "index.js",
+  "scripts": {
+    "start": "node index.js"
+  },
+  "dependencies": {
+    "@waku/zerokit-rln-wasm": "file:../../pkg"
+  }
+}

rln-wasm/resources/witness_calculator.js

@@ -1,4 +1,8 @@
-module.exports = async function builder(code, options) {
+// File generated with https://github.com/iden3/circom
+// following the instructions from:
+// https://github.com/vacp2p/zerokit/tree/master/rln#advanced-custom-circuit-compilation
+
+export async function builder(code, options) {
   options = options || {};
 
   let wasmModule;
@@ -101,7 +105,7 @@ module.exports = async function builder(code, options) {
     // Then append the value to the message we are creating
     msgStr += fromArray32(arr).toString();
   }
-};
+}
 
 class WitnessCalculator {
   constructor(instance, sanityCheck) {

rln-wasm/src/lib.rs

@@ -1,294 +1,16 @@
 #![cfg(target_arch = "wasm32")]
 
-use js_sys::{BigInt as JsBigInt, Object, Uint8Array};
-use num_bigint::BigInt;
-use rln::public::{hash, poseidon_hash, RLN};
-use std::vec::Vec;
-use wasm_bindgen::prelude::*;
+pub mod wasm_rln;
+pub mod wasm_utils;
 
+#[cfg(all(feature = "parallel", not(feature = "utils")))]
+pub use wasm_bindgen_rayon::init_thread_pool;
+#[cfg(not(feature = "utils"))]
+pub use wasm_rln::{WasmRLN, WasmRLNProof, WasmRLNProofValues, WasmRLNWitnessInput};
+pub use wasm_utils::{ExtendedIdentity, Hasher, Identity, VecWasmFr, WasmFr};
+
+#[cfg(feature = "panic_hook")]
 #[wasm_bindgen(js_name = initPanicHook)]
 pub fn init_panic_hook() {
     console_error_panic_hook::set_once();
 }
-
-#[wasm_bindgen(js_name = RLN)]
-pub struct RLNWrapper {
-    // The purpose of this wrapper is to hold a RLN instance with the 'static lifetime
-    // because wasm_bindgen does not allow returning elements with lifetimes
-    instance: RLN,
-}
-
-// Macro to call methods with arbitrary amount of arguments,
-// which have the last argument is output buffer pointer
-// First argument to the macro is context,
-// second is the actual method on `RLN`
-// third is the aforementioned output buffer argument
-// rest are all other arguments to the method
-macro_rules! call_with_output_and_error_msg {
-    // this variant is needed for the case when
-    // there are zero other arguments
-    ($instance:expr, $method:ident, $error_msg:expr) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            let new_instance = $instance.process();
-            if let Err(err) = new_instance.instance.$method(&mut output_data) {
-                std::mem::forget(output_data);
-                Err(format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-            } else {
-                let result = Uint8Array::from(&output_data[..]);
-                std::mem::forget(output_data);
-                Ok(result)
-            }
-        }
-    };
-    ($instance:expr, $method:ident, $error_msg:expr, $( $arg:expr ),* ) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            let new_instance = $instance.process();
-            if let Err(err) = new_instance.instance.$method($($arg.process()),*, &mut output_data) {
-                std::mem::forget(output_data);
-                Err(format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-            } else {
-                let result = Uint8Array::from(&output_data[..]);
-                std::mem::forget(output_data);
-                Ok(result)
-            }
-        }
-    };
-}
-
-macro_rules! call {
-    ($instance:expr, $method:ident $(, $arg:expr)*) => {
-        {
-            let new_instance: &mut RLNWrapper = $instance.process();
-            new_instance.instance.$method($($arg.process()),*)
-        }
-    }
-}
-
-macro_rules! call_bool_method_with_error_msg {
-    ($instance:expr, $method:ident, $error_msg:expr $(, $arg:expr)*) => {
-        {
-            let new_instance: &RLNWrapper = $instance.process();
-            new_instance.instance.$method($($arg.process()),*).map_err(|err| format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-        }
-    }
-}
-
-// Macro to execute a function with arbitrary amount of arguments,
-// First argument is the function to execute
-// Rest are all other arguments to the method
-macro_rules! fn_call_with_output_and_error_msg {
-    // this variant is needed for the case when
-    // there are zero other arguments
-    ($func:ident, $error_msg:expr) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            if let Err(err) = $func(&mut output_data) {
-                std::mem::forget(output_data);
-                Err(format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-            } else {
-                let result = Uint8Array::from(&output_data[..]);
-                std::mem::forget(output_data);
-                Ok(result)
-            }
-        }
-    };
-    ($func:ident, $error_msg:expr, $( $arg:expr ),* ) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            if let Err(err) = $func($($arg.process()),*, &mut output_data) {
-                std::mem::forget(output_data);
-                Err(format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-            } else {
-                let result = Uint8Array::from(&output_data[..]);
-                std::mem::forget(output_data);
-                Ok(result)
-            }
-        }
-    };
-}
-
-trait ProcessArg {
-    type ReturnType;
-    fn process(self) -> Self::ReturnType;
-}
-
-impl ProcessArg for usize {
-    type ReturnType = usize;
-    fn process(self) -> Self::ReturnType {
-        self
-    }
-}
-
-impl<T> ProcessArg for Vec<T> {
-    type ReturnType = Vec<T>;
-    fn process(self) -> Self::ReturnType {
-        self
-    }
-}
-
-impl ProcessArg for *const RLN {
-    type ReturnType = &'static RLN;
-    fn process(self) -> Self::ReturnType {
-        unsafe { &*self }
-    }
-}
-
-impl ProcessArg for *const RLNWrapper {
-    type ReturnType = &'static RLNWrapper;
-    fn process(self) -> Self::ReturnType {
-        unsafe { &*self }
-    }
-}
-
-impl ProcessArg for *mut RLNWrapper {
-    type ReturnType = &'static mut RLNWrapper;
-    fn process(self) -> Self::ReturnType {
-        unsafe { &mut *self }
-    }
-}
-
-impl<'a> ProcessArg for &'a [u8] {
-    type ReturnType = &'a [u8];
-
-    fn process(self) -> Self::ReturnType {
-        self
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = newRLN)]
-pub fn wasm_new(zkey: Uint8Array) -> Result<*mut RLNWrapper, String> {
-    let instance = RLN::new_with_params(zkey.to_vec()).map_err(|err| format!("{:#?}", err))?;
-    let wrapper = RLNWrapper { instance };
-    Ok(Box::into_raw(Box::new(wrapper)))
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = rlnWitnessToJson)]
-pub fn wasm_rln_witness_to_json(
-    ctx: *mut RLNWrapper,
-    serialized_witness: Uint8Array,
-) -> Result<Object, String> {
-    let inputs = call!(
-        ctx,
-        get_rln_witness_bigint_json,
-        &serialized_witness.to_vec()[..]
-    )
-    .map_err(|err| err.to_string())?;
-    let js_value = serde_wasm_bindgen::to_value(&inputs).map_err(|err| err.to_string())?;
-    Object::from_entries(&js_value).map_err(|err| format!("{:#?}", err))
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateRLNProofWithWitness)]
-pub fn wasm_generate_rln_proof_with_witness(
-    ctx: *mut RLNWrapper,
-    calculated_witness: Vec<JsBigInt>,
-    serialized_witness: Uint8Array,
-) -> Result<Uint8Array, String> {
-    let mut witness_vec: Vec<BigInt> = vec![];
-
-    for v in calculated_witness {
-        witness_vec.push(
-            v.to_string(10)
-                .map_err(|err| format!("{:#?}", err))?
-                .as_string()
-                .ok_or("not a string error")?
-                .parse::<BigInt>()
-                .map_err(|err| format!("{:#?}", err))?,
-        );
-    }
-
-    call_with_output_and_error_msg!(
-        ctx,
-        generate_rln_proof_with_witness,
-        "could not generate proof",
-        witness_vec,
-        serialized_witness.to_vec()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateMembershipKey)]
-pub fn wasm_key_gen(ctx: *const RLNWrapper) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(ctx, key_gen, "could not generate membership keys")
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateExtendedMembershipKey)]
-pub fn wasm_extended_key_gen(ctx: *const RLNWrapper) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(ctx, extended_key_gen, "could not generate membership keys")
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateSeededMembershipKey)]
-pub fn wasm_seeded_key_gen(ctx: *const RLNWrapper, seed: Uint8Array) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(
-        ctx,
-        seeded_key_gen,
-        "could not generate membership key",
-        &seed.to_vec()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateSeededExtendedMembershipKey)]
-pub fn wasm_seeded_extended_key_gen(
-    ctx: *const RLNWrapper,
-    seed: Uint8Array,
-) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(
-        ctx,
-        seeded_extended_key_gen,
-        "could not generate membership key",
-        &seed.to_vec()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = recovedIDSecret)]
-pub fn wasm_recover_id_secret(
-    ctx: *const RLNWrapper,
-    input_proof_data_1: Uint8Array,
-    input_proof_data_2: Uint8Array,
-) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(
-        ctx,
-        recover_id_secret,
-        "could not recover id secret",
-        &input_proof_data_1.to_vec()[..],
-        &input_proof_data_2.to_vec()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = verifyWithRoots)]
-pub fn wasm_verify_with_roots(
-    ctx: *const RLNWrapper,
-    proof: Uint8Array,
-    roots: Uint8Array,
-) -> Result<bool, String> {
-    call_bool_method_with_error_msg!(
-        ctx,
-        verify_with_roots,
-        "error while verifying proof with roots".to_string(),
-        &proof.to_vec()[..],
-        &roots.to_vec()[..]
-    )
-}
-
-#[wasm_bindgen(js_name = hash)]
-pub fn wasm_hash(input: Uint8Array) -> Result<Uint8Array, String> {
-    fn_call_with_output_and_error_msg!(hash, "could not generate hash", &input.to_vec()[..])
-}
-
-#[wasm_bindgen(js_name = poseidonHash)]
-pub fn wasm_poseidon_hash(input: Uint8Array) -> Result<Uint8Array, String> {
-    fn_call_with_output_and_error_msg!(
-        poseidon_hash,
-        "could not generate poseidon hash",
-        &input.to_vec()[..]
-    )
-}

rln-wasm/src/utils.js

@@ -1,26 +0,0 @@
-const fs = require("fs");
-
-// Utils functions for loading circom witness calculator and reading files from test
-
-module.exports = {
-  read_file: function (path) {
-    return fs.readFileSync(path);
-  },
-
-  calculateWitness: async function (circom_path, inputs) {
-    const wc = require("../resources/witness_calculator.js");
-    const wasmFile = fs.readFileSync(circom_path);
-    const wasmFileBuffer = wasmFile.slice(
-      wasmFile.byteOffset,
-      wasmFile.byteOffset + wasmFile.byteLength
-    );
-    const witnessCalculator = await wc(wasmFileBuffer);
-    const calculatedWitness = await witnessCalculator.calculateWitness(
-      inputs,
-      false
-    );
-    return JSON.stringify(calculatedWitness, (key, value) =>
-      typeof value === "bigint" ? value.toString() : value
-    );
-  },
-};

rln-wasm/src/wasm_rln.rs

@@ -0,0 +1,253 @@
+#![cfg(target_arch = "wasm32")]
+#![cfg(not(feature = "utils"))]
+
+use js_sys::{BigInt as JsBigInt, Object, Uint8Array};
+use num_bigint::BigInt;
+use rln::prelude::*;
+use serde::Serialize;
+use wasm_bindgen::prelude::*;
+
+use crate::wasm_utils::{VecWasmFr, WasmFr};
+
+#[wasm_bindgen]
+pub struct WasmRLN(RLN);
+
+#[wasm_bindgen]
+impl WasmRLN {
+    #[wasm_bindgen(constructor)]
+    pub fn new(zkey_data: &Uint8Array) -> Result<WasmRLN, String> {
+        let rln = RLN::new_with_params(zkey_data.to_vec()).map_err(|err| err.to_string())?;
+        Ok(WasmRLN(rln))
+    }
+
+    #[wasm_bindgen(js_name = generateRLNProofWithWitness)]
+    pub fn generate_rln_proof_with_witness(
+        &self,
+        calculated_witness: Vec<JsBigInt>,
+        witness: &WasmRLNWitnessInput,
+    ) -> Result<WasmRLNProof, String> {
+        let calculated_witness_bigint: Vec<BigInt> = calculated_witness
+            .iter()
+            .map(|js_bigint| {
+                js_bigint
+                    .to_string(10)
+                    .ok()
+                    .and_then(|js_str| js_str.as_string())
+                    .ok_or_else(|| "Failed to convert JsBigInt to string".to_string())
+                    .and_then(|str_val| {
+                        str_val
+                            .parse::<BigInt>()
+                            .map_err(|err| format!("Failed to parse BigInt: {}", err))
+                    })
+            })
+            .collect::<Result<Vec<_>, _>>()?;
+
+        let (proof, proof_values) = self
+            .0
+            .generate_rln_proof_with_witness(calculated_witness_bigint, &witness.0)
+            .map_err(|err| err.to_string())?;
+
+        let rln_proof = RLNProof {
+            proof_values,
+            proof,
+        };
+
+        Ok(WasmRLNProof(rln_proof))
+    }
+
+    #[wasm_bindgen(js_name = verifyWithRoots)]
+    pub fn verify_with_roots(
+        &self,
+        rln_proof: &WasmRLNProof,
+        roots: &VecWasmFr,
+        x: &WasmFr,
+    ) -> Result<bool, String> {
+        let roots_fr: Vec<Fr> = (0..roots.length())
+            .filter_map(|i| roots.get(i))
+            .map(|root| *root)
+            .collect();
+
+        self.0
+            .verify_with_roots(&rln_proof.0.proof, &rln_proof.0.proof_values, x, &roots_fr)
+            .map_err(|err| err.to_string())
+    }
+}
+
+#[wasm_bindgen]
+pub struct WasmRLNProof(RLNProof);
+
+#[wasm_bindgen]
+impl WasmRLNProof {
+    #[wasm_bindgen(js_name = getValues)]
+    pub fn get_values(&self) -> WasmRLNProofValues {
+        WasmRLNProofValues(self.0.proof_values)
+    }
+
+    #[wasm_bindgen(js_name = toBytesLE)]
+    pub fn to_bytes_le(&self) -> Result<Uint8Array, String> {
+        let bytes = rln_proof_to_bytes_le(&self.0).map_err(|err| err.to_string())?;
+        Ok(Uint8Array::from(&bytes[..]))
+    }
+
+    #[wasm_bindgen(js_name = toBytesBE)]
+    pub fn to_bytes_be(&self) -> Result<Uint8Array, String> {
+        let bytes = rln_proof_to_bytes_be(&self.0).map_err(|err| err.to_string())?;
+        Ok(Uint8Array::from(&bytes[..]))
+    }
+
+    #[wasm_bindgen(js_name = fromBytesLE)]
+    pub fn from_bytes_le(bytes: &Uint8Array) -> Result<WasmRLNProof, String> {
+        let bytes_vec = bytes.to_vec();
+        let (proof, _) = bytes_le_to_rln_proof(&bytes_vec).map_err(|err| err.to_string())?;
+        Ok(WasmRLNProof(proof))
+    }
+
+    #[wasm_bindgen(js_name = fromBytesBE)]
+    pub fn from_bytes_be(bytes: &Uint8Array) -> Result<WasmRLNProof, String> {
+        let bytes_vec = bytes.to_vec();
+        let (proof, _) = bytes_be_to_rln_proof(&bytes_vec).map_err(|err| err.to_string())?;
+        Ok(WasmRLNProof(proof))
+    }
+}
+
+#[wasm_bindgen]
+pub struct WasmRLNProofValues(RLNProofValues);
+
+#[wasm_bindgen]
+impl WasmRLNProofValues {
+    #[wasm_bindgen(getter)]
+    pub fn y(&self) -> WasmFr {
+        WasmFr::from(self.0.y)
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn nullifier(&self) -> WasmFr {
+        WasmFr::from(self.0.nullifier)
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn root(&self) -> WasmFr {
+        WasmFr::from(self.0.root)
+    }
+
+    #[wasm_bindgen(getter)]
+    pub fn x(&self) -> WasmFr {
+        WasmFr::from(self.0.x)
+    }
+
+    #[wasm_bindgen(getter, js_name = externalNullifier)]
+    pub fn external_nullifier(&self) -> WasmFr {
+        WasmFr::from(self.0.external_nullifier)
+    }
+
+    #[wasm_bindgen(js_name = toBytesLE)]
+    pub fn to_bytes_le(&self) -> Uint8Array {
+        Uint8Array::from(&rln_proof_values_to_bytes_le(&self.0)[..])
+    }
+
+    #[wasm_bindgen(js_name = toBytesBE)]
+    pub fn to_bytes_be(&self) -> Uint8Array {
+        Uint8Array::from(&rln_proof_values_to_bytes_be(&self.0)[..])
+    }
+
+    #[wasm_bindgen(js_name = fromBytesLE)]
+    pub fn from_bytes_le(bytes: &Uint8Array) -> Result<WasmRLNProofValues, String> {
+        let bytes_vec = bytes.to_vec();
+        let (proof_values, _) =
+            bytes_le_to_rln_proof_values(&bytes_vec).map_err(|err| err.to_string())?;
+        Ok(WasmRLNProofValues(proof_values))
+    }
+
+    #[wasm_bindgen(js_name = fromBytesBE)]
+    pub fn from_bytes_be(bytes: &Uint8Array) -> Result<WasmRLNProofValues, String> {
+        let bytes_vec = bytes.to_vec();
+        let (proof_values, _) =
+            bytes_be_to_rln_proof_values(&bytes_vec).map_err(|err| err.to_string())?;
+        Ok(WasmRLNProofValues(proof_values))
+    }
+
+    #[wasm_bindgen(js_name = recoverIdSecret)]
+    pub fn recover_id_secret(
+        proof_values_1: &WasmRLNProofValues,
+        proof_values_2: &WasmRLNProofValues,
+    ) -> Result<WasmFr, String> {
+        let recovered_identity_secret = recover_id_secret(&proof_values_1.0, &proof_values_2.0)
+            .map_err(|err| err.to_string())?;
+
+        Ok(WasmFr::from(*recovered_identity_secret))
+    }
+}
+
+#[wasm_bindgen]
+pub struct WasmRLNWitnessInput(RLNWitnessInput);
+
+#[wasm_bindgen]
+impl WasmRLNWitnessInput {
+    #[wasm_bindgen(constructor)]
+    pub fn new(
+        identity_secret: &WasmFr,
+        user_message_limit: &WasmFr,
+        message_id: &WasmFr,
+        path_elements: &VecWasmFr,
+        identity_path_index: &Uint8Array,
+        x: &WasmFr,
+        external_nullifier: &WasmFr,
+    ) -> Result<WasmRLNWitnessInput, String> {
+        let mut identity_secret_fr = identity_secret.inner();
+        let path_elements: Vec<Fr> = path_elements.inner();
+        let identity_path_index: Vec<u8> = identity_path_index.to_vec();
+
+        let witness = RLNWitnessInput::new(
+            IdSecret::from(&mut identity_secret_fr),
+            user_message_limit.inner(),
+            message_id.inner(),
+            path_elements,
+            identity_path_index,
+            x.inner(),
+            external_nullifier.inner(),
+        )
+        .map_err(|err| err.to_string())?;
+
+        Ok(WasmRLNWitnessInput(witness))
+    }
+
+    #[wasm_bindgen(js_name = toBigIntJson)]
+    pub fn to_bigint_json(&self) -> Result<Object, String> {
+        let bigint_json = rln_witness_to_bigint_json(&self.0).map_err(|err| err.to_string())?;
+
+        let serializer = serde_wasm_bindgen::Serializer::json_compatible();
+        let js_value = bigint_json
+            .serialize(&serializer)
+            .map_err(|err| err.to_string())?;
+
+        js_value
+            .dyn_into::<Object>()
+            .map_err(|err| format!("{:#?}", err))
+    }
+
+    #[wasm_bindgen(js_name = toBytesLE)]
+    pub fn to_bytes_le(&self) -> Result<Uint8Array, String> {
+        let bytes = rln_witness_to_bytes_le(&self.0).map_err(|err| err.to_string())?;
+        Ok(Uint8Array::from(&bytes[..]))
+    }
+
+    #[wasm_bindgen(js_name = toBytesBE)]
+    pub fn to_bytes_be(&self) -> Result<Uint8Array, String> {
+        let bytes = rln_witness_to_bytes_be(&self.0).map_err(|err| err.to_string())?;
+        Ok(Uint8Array::from(&bytes[..]))
+    }
+
+    #[wasm_bindgen(js_name = fromBytesLE)]
+    pub fn from_bytes_le(bytes: &Uint8Array) -> Result<WasmRLNWitnessInput, String> {
+        let bytes_vec = bytes.to_vec();
+        let (witness, _) = bytes_le_to_rln_witness(&bytes_vec).map_err(|err| err.to_string())?;
+        Ok(WasmRLNWitnessInput(witness))
+    }
+
+    #[wasm_bindgen(js_name = fromBytesBE)]
+    pub fn from_bytes_be(bytes: &Uint8Array) -> Result<WasmRLNWitnessInput, String> {
+        let bytes_vec = bytes.to_vec();
+        let (witness, _) = bytes_be_to_rln_witness(&bytes_vec).map_err(|err| err.to_string())?;
+        Ok(WasmRLNWitnessInput(witness))
+    }
+}

rln-wasm/src/wasm_utils.rs

@@ -0,0 +1,420 @@
+#![cfg(target_arch = "wasm32")]
+
+use std::ops::Deref;
+
+use js_sys::Uint8Array;
+use rln::prelude::*;
+use wasm_bindgen::prelude::*;
+
+// WasmFr
+
+#[wasm_bindgen]
+#[derive(Debug, Clone, Copy, PartialEq, Default)]
+pub struct WasmFr(Fr);
+
+impl From<Fr> for WasmFr {
+    fn from(fr: Fr) -> Self {
+        Self(fr)
+    }
+}
+
+impl Deref for WasmFr {
+    type Target = Fr;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+#[wasm_bindgen]
+impl WasmFr {
+    #[wasm_bindgen(js_name = zero)]
+    pub fn zero() -> Self {
+        Self(Fr::from(0u32))
+    }
+
+    #[wasm_bindgen(js_name = one)]
+    pub fn one() -> Self {
+        Self(Fr::from(1u32))
+    }
+
+    #[wasm_bindgen(js_name = fromUint)]
+    pub fn from_uint(value: u32) -> Self {
+        Self(Fr::from(value))
+    }
+
+    #[wasm_bindgen(js_name = fromBytesLE)]
+    pub fn from_bytes_le(bytes: &Uint8Array) -> Result<Self, String> {
+        let bytes_vec = bytes.to_vec();
+        let (fr, _) = bytes_le_to_fr(&bytes_vec).map_err(|err| err.to_string())?;
+        Ok(Self(fr))
+    }
+
+    #[wasm_bindgen(js_name = fromBytesBE)]
+    pub fn from_bytes_be(bytes: &Uint8Array) -> Result<Self, String> {
+        let bytes_vec = bytes.to_vec();
+        let (fr, _) = bytes_be_to_fr(&bytes_vec).map_err(|err| err.to_string())?;
+        Ok(Self(fr))
+    }
+
+    #[wasm_bindgen(js_name = toBytesLE)]
+    pub fn to_bytes_le(&self) -> Uint8Array {
+        let bytes = fr_to_bytes_le(&self.0);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = toBytesBE)]
+    pub fn to_bytes_be(&self) -> Uint8Array {
+        let bytes = fr_to_bytes_be(&self.0);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = debug)]
+    pub fn debug(&self) -> String {
+        format!("{:?}", self.0)
+    }
+}
+
+impl WasmFr {
+    pub fn inner(&self) -> Fr {
+        self.0
+    }
+}
+
+// VecWasmFr
+
+#[wasm_bindgen]
+#[derive(Debug, Clone, PartialEq, Default)]
+pub struct VecWasmFr(Vec<Fr>);
+
+#[wasm_bindgen]
+impl VecWasmFr {
+    #[wasm_bindgen(constructor)]
+    pub fn new() -> Self {
+        Self(Vec::new())
+    }
+
+    #[wasm_bindgen(js_name = fromBytesLE)]
+    pub fn from_bytes_le(bytes: &Uint8Array) -> Result<VecWasmFr, String> {
+        let bytes_vec = bytes.to_vec();
+        bytes_le_to_vec_fr(&bytes_vec)
+            .map(|(vec_fr, _)| VecWasmFr(vec_fr))
+            .map_err(|err| err.to_string())
+    }
+
+    #[wasm_bindgen(js_name = fromBytesBE)]
+    pub fn from_bytes_be(bytes: &Uint8Array) -> Result<VecWasmFr, String> {
+        let bytes_vec = bytes.to_vec();
+        bytes_be_to_vec_fr(&bytes_vec)
+            .map(|(vec_fr, _)| VecWasmFr(vec_fr))
+            .map_err(|err| err.to_string())
+    }
+
+    #[wasm_bindgen(js_name = toBytesLE)]
+    pub fn to_bytes_le(&self) -> Uint8Array {
+        let bytes = vec_fr_to_bytes_le(&self.0);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = toBytesBE)]
+    pub fn to_bytes_be(&self) -> Uint8Array {
+        let bytes = vec_fr_to_bytes_be(&self.0);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = get)]
+    pub fn get(&self, index: usize) -> Option<WasmFr> {
+        self.0.get(index).map(|&fr| WasmFr(fr))
+    }
+
+    #[wasm_bindgen(js_name = length)]
+    pub fn length(&self) -> usize {
+        self.0.len()
+    }
+
+    #[wasm_bindgen(js_name = push)]
+    pub fn push(&mut self, element: &WasmFr) {
+        self.0.push(element.0);
+    }
+
+    #[wasm_bindgen(js_name = debug)]
+    pub fn debug(&self) -> String {
+        format!("{:?}", self.0)
+    }
+}
+
+impl VecWasmFr {
+    pub fn inner(&self) -> Vec<Fr> {
+        self.0.clone()
+    }
+}
+
+// Uint8Array
+
+#[wasm_bindgen]
+pub struct Uint8ArrayUtils;
+
+#[wasm_bindgen]
+impl Uint8ArrayUtils {
+    #[wasm_bindgen(js_name = toBytesLE)]
+    pub fn to_bytes_le(input: &Uint8Array) -> Uint8Array {
+        let input_vec = input.to_vec();
+        let bytes = vec_u8_to_bytes_le(&input_vec);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = toBytesBE)]
+    pub fn to_bytes_be(input: &Uint8Array) -> Uint8Array {
+        let input_vec = input.to_vec();
+        let bytes = vec_u8_to_bytes_be(&input_vec);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = fromBytesLE)]
+    pub fn from_bytes_le(bytes: &Uint8Array) -> Result<Uint8Array, String> {
+        let bytes_vec = bytes.to_vec();
+        bytes_le_to_vec_u8(&bytes_vec)
+            .map(|(vec_u8, _)| Uint8Array::from(&vec_u8[..]))
+            .map_err(|err| err.to_string())
+    }
+
+    #[wasm_bindgen(js_name = fromBytesBE)]
+    pub fn from_bytes_be(bytes: &Uint8Array) -> Result<Uint8Array, String> {
+        let bytes_vec = bytes.to_vec();
+        bytes_be_to_vec_u8(&bytes_vec)
+            .map(|(vec_u8, _)| Uint8Array::from(&vec_u8[..]))
+            .map_err(|err| err.to_string())
+    }
+}
+
+// Utility APIs
+
+#[wasm_bindgen]
+pub struct Hasher;
+
+#[wasm_bindgen]
+impl Hasher {
+    #[wasm_bindgen(js_name = hashToFieldLE)]
+    pub fn hash_to_field_le(input: &Uint8Array) -> Result<WasmFr, String> {
+        hash_to_field_le(&input.to_vec())
+            .map(WasmFr)
+            .map_err(|err| err.to_string())
+    }
+
+    #[wasm_bindgen(js_name = hashToFieldBE)]
+    pub fn hash_to_field_be(input: &Uint8Array) -> Result<WasmFr, String> {
+        hash_to_field_be(&input.to_vec())
+            .map(WasmFr)
+            .map_err(|err| err.to_string())
+    }
+
+    #[wasm_bindgen(js_name = poseidonHashPair)]
+    pub fn poseidon_hash_pair(a: &WasmFr, b: &WasmFr) -> Result<WasmFr, String> {
+        poseidon_hash(&[a.0, b.0])
+            .map(WasmFr)
+            .map_err(|err| err.to_string())
+    }
+}
+
+#[wasm_bindgen]
+pub struct Identity {
+    identity_secret: Fr,
+    id_commitment: Fr,
+}
+
+#[wasm_bindgen]
+impl Identity {
+    #[wasm_bindgen(js_name = generate)]
+    pub fn generate() -> Result<Identity, String> {
+        let (identity_secret, id_commitment) = keygen().map_err(|err| err.to_string())?;
+        Ok(Identity {
+            identity_secret: *identity_secret,
+            id_commitment,
+        })
+    }
+
+    #[wasm_bindgen(js_name = generateSeeded)]
+    pub fn generate_seeded(seed: &Uint8Array) -> Result<Identity, String> {
+        let seed_vec = seed.to_vec();
+        let (identity_secret, id_commitment) =
+            seeded_keygen(&seed_vec).map_err(|err| err.to_string())?;
+        Ok(Identity {
+            identity_secret,
+            id_commitment,
+        })
+    }
+
+    #[wasm_bindgen(js_name = getSecretHash)]
+    pub fn get_secret_hash(&self) -> WasmFr {
+        WasmFr(self.identity_secret)
+    }
+
+    #[wasm_bindgen(js_name = getCommitment)]
+    pub fn get_commitment(&self) -> WasmFr {
+        WasmFr(self.id_commitment)
+    }
+
+    #[wasm_bindgen(js_name = toArray)]
+    pub fn to_array(&self) -> VecWasmFr {
+        VecWasmFr(vec![self.identity_secret, self.id_commitment])
+    }
+
+    #[wasm_bindgen(js_name = toBytesLE)]
+    pub fn to_bytes_le(&self) -> Uint8Array {
+        let vec_fr = vec![self.identity_secret, self.id_commitment];
+        let bytes = vec_fr_to_bytes_le(&vec_fr);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = toBytesBE)]
+    pub fn to_bytes_be(&self) -> Uint8Array {
+        let vec_fr = vec![self.identity_secret, self.id_commitment];
+        let bytes = vec_fr_to_bytes_be(&vec_fr);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = fromBytesLE)]
+    pub fn from_bytes_le(bytes: &Uint8Array) -> Result<Identity, String> {
+        let bytes_vec = bytes.to_vec();
+        let (vec_fr, _) = bytes_le_to_vec_fr(&bytes_vec).map_err(|err| err.to_string())?;
+        if vec_fr.len() != 2 {
+            return Err(format!("Expected 2 elements, got {}", vec_fr.len()));
+        }
+        Ok(Identity {
+            identity_secret: vec_fr[0],
+            id_commitment: vec_fr[1],
+        })
+    }
+
+    #[wasm_bindgen(js_name = fromBytesBE)]
+    pub fn from_bytes_be(bytes: &Uint8Array) -> Result<Identity, String> {
+        let bytes_vec = bytes.to_vec();
+        let (vec_fr, _) = bytes_be_to_vec_fr(&bytes_vec).map_err(|err| err.to_string())?;
+        if vec_fr.len() != 2 {
+            return Err(format!("Expected 2 elements, got {}", vec_fr.len()));
+        }
+        Ok(Identity {
+            identity_secret: vec_fr[0],
+            id_commitment: vec_fr[1],
+        })
+    }
+}
+
+#[wasm_bindgen]
+pub struct ExtendedIdentity {
+    identity_trapdoor: Fr,
+    identity_nullifier: Fr,
+    identity_secret: Fr,
+    id_commitment: Fr,
+}
+
+#[wasm_bindgen]
+impl ExtendedIdentity {
+    #[wasm_bindgen(js_name = generate)]
+    pub fn generate() -> Result<ExtendedIdentity, String> {
+        let (identity_trapdoor, identity_nullifier, identity_secret, id_commitment) =
+            extended_keygen().map_err(|err| err.to_string())?;
+        Ok(ExtendedIdentity {
+            identity_trapdoor,
+            identity_nullifier,
+            identity_secret,
+            id_commitment,
+        })
+    }
+
+    #[wasm_bindgen(js_name = generateSeeded)]
+    pub fn generate_seeded(seed: &Uint8Array) -> Result<ExtendedIdentity, String> {
+        let seed_vec = seed.to_vec();
+        let (identity_trapdoor, identity_nullifier, identity_secret, id_commitment) =
+            extended_seeded_keygen(&seed_vec).map_err(|err| err.to_string())?;
+        Ok(ExtendedIdentity {
+            identity_trapdoor,
+            identity_nullifier,
+            identity_secret,
+            id_commitment,
+        })
+    }
+
+    #[wasm_bindgen(js_name = getTrapdoor)]
+    pub fn get_trapdoor(&self) -> WasmFr {
+        WasmFr(self.identity_trapdoor)
+    }
+
+    #[wasm_bindgen(js_name = getNullifier)]
+    pub fn get_nullifier(&self) -> WasmFr {
+        WasmFr(self.identity_nullifier)
+    }
+
+    #[wasm_bindgen(js_name = getSecretHash)]
+    pub fn get_secret_hash(&self) -> WasmFr {
+        WasmFr(self.identity_secret)
+    }
+
+    #[wasm_bindgen(js_name = getCommitment)]
+    pub fn get_commitment(&self) -> WasmFr {
+        WasmFr(self.id_commitment)
+    }
+
+    #[wasm_bindgen(js_name = toArray)]
+    pub fn to_array(&self) -> VecWasmFr {
+        VecWasmFr(vec![
+            self.identity_trapdoor,
+            self.identity_nullifier,
+            self.identity_secret,
+            self.id_commitment,
+        ])
+    }
+
+    #[wasm_bindgen(js_name = toBytesLE)]
+    pub fn to_bytes_le(&self) -> Uint8Array {
+        let vec_fr = vec![
+            self.identity_trapdoor,
+            self.identity_nullifier,
+            self.identity_secret,
+            self.id_commitment,
+        ];
+        let bytes = vec_fr_to_bytes_le(&vec_fr);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = toBytesBE)]
+    pub fn to_bytes_be(&self) -> Uint8Array {
+        let vec_fr = vec![
+            self.identity_trapdoor,
+            self.identity_nullifier,
+            self.identity_secret,
+            self.id_commitment,
+        ];
+        let bytes = vec_fr_to_bytes_be(&vec_fr);
+        Uint8Array::from(&bytes[..])
+    }
+
+    #[wasm_bindgen(js_name = fromBytesLE)]
+    pub fn from_bytes_le(bytes: &Uint8Array) -> Result<ExtendedIdentity, String> {
+        let bytes_vec = bytes.to_vec();
+        let (vec_fr, _) = bytes_le_to_vec_fr(&bytes_vec).map_err(|err| err.to_string())?;
+        if vec_fr.len() != 4 {
+            return Err(format!("Expected 4 elements, got {}", vec_fr.len()));
+        }
+        Ok(ExtendedIdentity {
+            identity_trapdoor: vec_fr[0],
+            identity_nullifier: vec_fr[1],
+            identity_secret: vec_fr[2],
+            id_commitment: vec_fr[3],
+        })
+    }
+
+    #[wasm_bindgen(js_name = fromBytesBE)]
+    pub fn from_bytes_be(bytes: &Uint8Array) -> Result<ExtendedIdentity, String> {
+        let bytes_vec = bytes.to_vec();
+        let (vec_fr, _) = bytes_be_to_vec_fr(&bytes_vec).map_err(|err| err.to_string())?;
+        if vec_fr.len() != 4 {
+            return Err(format!("Expected 4 elements, got {}", vec_fr.len()));
+        }
+        Ok(ExtendedIdentity {
+            identity_trapdoor: vec_fr[0],
+            identity_nullifier: vec_fr[1],
+            identity_secret: vec_fr[2],
+            id_commitment: vec_fr[3],
+        })
+    }
+}

rln-wasm/tests/browser.rs

@@ -0,0 +1,247 @@
+#![cfg(target_arch = "wasm32")]
+#![cfg(not(feature = "utils"))]
+
+#[cfg(test)]
+mod test {
+    use js_sys::{BigInt as JsBigInt, Date, Object, Uint8Array};
+    use rln::prelude::*;
+    use rln_wasm::{
+        Hasher, Identity, VecWasmFr, WasmFr, WasmRLN, WasmRLNProof, WasmRLNWitnessInput,
+    };
+    use wasm_bindgen::{prelude::wasm_bindgen, JsValue};
+    use wasm_bindgen_test::{console_log, wasm_bindgen_test, wasm_bindgen_test_configure};
+    use zerokit_utils::merkle_tree::{
+        OptimalMerkleProof, OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree,
+    };
+    #[cfg(feature = "parallel")]
+    use {rln_wasm::init_thread_pool, wasm_bindgen_futures::JsFuture, web_sys::window};
+
+    #[wasm_bindgen(inline_js = r#"
+    export function isThreadpoolSupported() {
+      return typeof SharedArrayBuffer !== 'undefined' &&
+             typeof Atomics !== 'undefined' &&
+             typeof crossOriginIsolated !== 'undefined' &&
+             crossOriginIsolated;
+    }
+
+    export function initWitnessCalculator(jsCode) {
+      const processedCode = jsCode
+        .replace(/export\s+async\s+function\s+builder/, 'async function builder')
+        .replace(/export\s*\{\s*builder\s*\};?/g, '');
+
+      const moduleFunc = new Function(processedCode + '\nreturn { builder };');
+      const witnessCalculatorModule = moduleFunc();
+
+      window.witnessCalculatorBuilder = witnessCalculatorModule.builder;
+
+      if (typeof window.witnessCalculatorBuilder !== 'function') {
+        return false;
+      }
+      return true;
+    }
+
+    export function readFile(data) {
+      return new Uint8Array(data);
+    }
+
+    export async function calculateWitness(circom_data, inputs) {
+      const wasmBuffer = circom_data instanceof Uint8Array ? circom_data : new Uint8Array(circom_data);
+      const witnessCalculator = await window.witnessCalculatorBuilder(wasmBuffer);
+      const calculatedWitness = await witnessCalculator.calculateWitness(inputs, false);
+      return JSON.stringify(calculatedWitness, (key, value) =>
+        typeof value === "bigint" ? value.toString() : value
+      );
+    }
+    "#)]
+    extern "C" {
+        #[wasm_bindgen(catch)]
+        fn isThreadpoolSupported() -> Result<bool, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        fn initWitnessCalculator(js: &str) -> Result<bool, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        fn readFile(data: &[u8]) -> Result<Uint8Array, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        async fn calculateWitness(circom_data: &[u8], inputs: Object) -> Result<JsValue, JsValue>;
+    }
+
+    const WITNESS_CALCULATOR_JS: &str = include_str!("../resources/witness_calculator.js");
+
+    const ARKZKEY_BYTES: &[u8] =
+        include_bytes!("../../rln/resources/tree_depth_20/rln_final.arkzkey");
+
+    const CIRCOM_BYTES: &[u8] = include_bytes!("../../rln/resources/tree_depth_20/rln.wasm");
+
+    wasm_bindgen_test_configure!(run_in_browser);
+
+    #[wasm_bindgen_test]
+    pub async fn rln_wasm_benchmark() {
+        // Check if thread pool is supported
+        #[cfg(feature = "parallel")]
+        if !isThreadpoolSupported().unwrap() {
+            panic!("Thread pool is NOT supported");
+        } else {
+            // Initialize thread pool
+            let cpu_count = window().unwrap().navigator().hardware_concurrency() as usize;
+            JsFuture::from(init_thread_pool(cpu_count)).await.unwrap();
+        }
+
+        // Initialize witness calculator
+        initWitnessCalculator(WITNESS_CALCULATOR_JS).unwrap();
+
+        let mut results = String::from("\nbenchmarks:\n");
+        let iterations = 10;
+
+        let zkey = readFile(ARKZKEY_BYTES).unwrap();
+
+        // Benchmark RLN instance creation
+        let start_rln_new = Date::now();
+        for _ in 0..iterations {
+            let _ = WasmRLN::new(&zkey).unwrap();
+        }
+        let rln_new_result = Date::now() - start_rln_new;
+
+        // Create RLN instance for other benchmarks
+        let rln_instance = WasmRLN::new(&zkey).unwrap();
+        let mut tree: OptimalMerkleTree<PoseidonHash> =
+            OptimalMerkleTree::default(DEFAULT_TREE_DEPTH).unwrap();
+
+        // Benchmark generate identity
+        let start_identity_gen = Date::now();
+        for _ in 0..iterations {
+            let _ = Identity::generate().unwrap();
+        }
+        let identity_gen_result = Date::now() - start_identity_gen;
+
+        // Generate identity for other benchmarks
+        let identity_pair = Identity::generate().unwrap();
+        let identity_secret = identity_pair.get_secret_hash();
+        let id_commitment = identity_pair.get_commitment();
+
+        let epoch = Hasher::hash_to_field_le(&Uint8Array::from(b"test-epoch" as &[u8])).unwrap();
+        let rln_identifier =
+            Hasher::hash_to_field_le(&Uint8Array::from(b"test-rln-identifier" as &[u8])).unwrap();
+        let external_nullifier = Hasher::poseidon_hash_pair(&epoch, &rln_identifier).unwrap();
+
+        let identity_index = tree.leaves_set();
+
+        let user_message_limit = WasmFr::from_uint(100);
+
+        let rate_commitment =
+            Hasher::poseidon_hash_pair(&id_commitment, &user_message_limit).unwrap();
+        tree.update_next(*rate_commitment).unwrap();
+
+        let message_id = WasmFr::from_uint(0);
+        let signal: [u8; 32] = [0; 32];
+        let x = Hasher::hash_to_field_le(&Uint8Array::from(&signal[..])).unwrap();
+
+        let merkle_proof: OptimalMerkleProof<PoseidonHash> = tree.proof(identity_index).unwrap();
+
+        let mut path_elements = VecWasmFr::new();
+        for path_element in merkle_proof.get_path_elements() {
+            path_elements.push(&WasmFr::from(path_element));
+        }
+        let path_index = Uint8Array::from(&merkle_proof.get_path_index()[..]);
+
+        let witness = WasmRLNWitnessInput::new(
+            &identity_secret,
+            &user_message_limit,
+            &message_id,
+            &path_elements,
+            &path_index,
+            &x,
+            &external_nullifier,
+        )
+        .unwrap();
+
+        let bigint_json = witness.to_bigint_json().unwrap();
+
+        // Benchmark witness calculation
+        let start_calculate_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = calculateWitness(CIRCOM_BYTES, bigint_json.clone())
+                .await
+                .unwrap();
+        }
+        let calculate_witness_result = Date::now() - start_calculate_witness;
+
+        // Calculate witness for other benchmarks
+        let calculated_witness_str = calculateWitness(CIRCOM_BYTES, bigint_json.clone())
+            .await
+            .unwrap()
+            .as_string()
+            .unwrap();
+        let calculated_witness_vec_str: Vec<String> =
+            serde_json::from_str(&calculated_witness_str).unwrap();
+        let calculated_witness: Vec<JsBigInt> = calculated_witness_vec_str
+            .iter()
+            .map(|x| JsBigInt::new(&x.into()).unwrap())
+            .collect();
+
+        // Benchmark proof generation with witness
+        let start_generate_rln_proof_with_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = rln_instance
+                .generate_rln_proof_with_witness(calculated_witness.clone(), &witness)
+                .unwrap();
+        }
+        let generate_rln_proof_with_witness_result =
+            Date::now() - start_generate_rln_proof_with_witness;
+
+        // Generate proof with witness for other benchmarks
+        let proof: WasmRLNProof = rln_instance
+            .generate_rln_proof_with_witness(calculated_witness, &witness)
+            .unwrap();
+
+        let root = WasmFr::from(tree.root());
+        let mut roots = VecWasmFr::new();
+        roots.push(&root);
+
+        // Benchmark proof verification with the root
+        let start_verify_with_roots = Date::now();
+        for _ in 0..iterations {
+            let _ = rln_instance.verify_with_roots(&proof, &roots, &x).unwrap();
+        }
+        let verify_with_roots_result = Date::now() - start_verify_with_roots;
+
+        // Verify proof with the root for other benchmarks
+        let is_proof_valid = rln_instance.verify_with_roots(&proof, &roots, &x).unwrap();
+        assert!(is_proof_valid, "verification failed");
+
+        // Format and display the benchmark results
+        let format_duration = |duration_ms: f64| -> String {
+            let avg_ms = duration_ms / (iterations as f64);
+            if avg_ms >= 1000.0 {
+                format!("{:.3} s", avg_ms / 1000.0)
+            } else {
+                format!("{:.3} ms", avg_ms)
+            }
+        };
+
+        results.push_str(&format!(
+            "RLN instance creation: {}\n",
+            format_duration(rln_new_result)
+        ));
+        results.push_str(&format!(
+            "Identity generation: {}\n",
+            format_duration(identity_gen_result)
+        ));
+        results.push_str(&format!(
+            "Witness calculation: {}\n",
+            format_duration(calculate_witness_result)
+        ));
+        results.push_str(&format!(
+            "Proof generation with witness: {}\n",
+            format_duration(generate_rln_proof_with_witness_result)
+        ));
+        results.push_str(&format!(
+            "Proof verification with roots: {}\n",
+            format_duration(verify_with_roots_result)
+        ));
+
+        // Log the results
+        console_log!("{results}");
+    }
+}

rln-wasm/tests/node.rs

@@ -0,0 +1,233 @@
+#![cfg(target_arch = "wasm32")]
+#![cfg(not(feature = "utils"))]
+
+#[cfg(test)]
+mod test {
+    use js_sys::{BigInt as JsBigInt, Date, Object, Uint8Array};
+    use rln::prelude::*;
+    use rln_wasm::{
+        Hasher, Identity, VecWasmFr, WasmFr, WasmRLN, WasmRLNProof, WasmRLNWitnessInput,
+    };
+    use wasm_bindgen::{prelude::wasm_bindgen, JsValue};
+    use wasm_bindgen_test::{console_log, wasm_bindgen_test};
+    use zerokit_utils::merkle_tree::{
+        OptimalMerkleProof, OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree,
+    };
+
+    #[wasm_bindgen(inline_js = r#"
+    const fs = require("fs");
+
+    let witnessCalculatorModule = null;
+
+    module.exports = {
+      initWitnessCalculator: function(code) {
+        const processedCode = code
+          .replace(/export\s+async\s+function\s+builder/, 'async function builder')
+          .replace(/export\s*\{\s*builder\s*\};?/g, '');
+
+        const moduleFunc = new Function(processedCode + '\nreturn { builder };');
+        witnessCalculatorModule = moduleFunc();
+
+        if (typeof witnessCalculatorModule.builder !== 'function') {
+          return false;
+        }
+        return true;
+      },
+
+      readFile: function (path) {
+        return fs.readFileSync(path);
+      },
+
+      calculateWitness: async function (circom_path, inputs) {
+        const wasmFile = fs.readFileSync(circom_path);
+        const wasmFileBuffer = wasmFile.buffer.slice(
+          wasmFile.byteOffset,
+          wasmFile.byteOffset + wasmFile.byteLength
+        );
+        const witnessCalculator = await witnessCalculatorModule.builder(wasmFileBuffer);
+        const calculatedWitness = await witnessCalculator.calculateWitness(
+          inputs,
+          false
+        );
+        return JSON.stringify(calculatedWitness, (key, value) =>
+          typeof value === "bigint" ? value.toString() : value
+        );
+      },
+    };
+    "#)]
+    extern "C" {
+        #[wasm_bindgen(catch)]
+        fn initWitnessCalculator(code: &str) -> Result<bool, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        fn readFile(path: &str) -> Result<Uint8Array, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        async fn calculateWitness(circom_path: &str, input: Object) -> Result<JsValue, JsValue>;
+    }
+
+    const WITNESS_CALCULATOR_JS: &str = include_str!("../resources/witness_calculator.js");
+
+    const ARKZKEY_PATH: &str = "../rln/resources/tree_depth_20/rln_final.arkzkey";
+
+    const CIRCOM_PATH: &str = "../rln/resources/tree_depth_20/rln.wasm";
+
+    #[wasm_bindgen_test]
+    pub async fn rln_wasm_benchmark() {
+        // Initialize witness calculator
+        initWitnessCalculator(WITNESS_CALCULATOR_JS).unwrap();
+
+        let mut results = String::from("\nbenchmarks:\n");
+        let iterations = 10;
+
+        let zkey = readFile(ARKZKEY_PATH).unwrap();
+
+        // Benchmark RLN instance creation
+        let start_rln_new = Date::now();
+        for _ in 0..iterations {
+            let _ = WasmRLN::new(&zkey).unwrap();
+        }
+        let rln_new_result = Date::now() - start_rln_new;
+
+        // Create RLN instance for other benchmarks
+        let rln_instance = WasmRLN::new(&zkey).unwrap();
+        let mut tree: OptimalMerkleTree<PoseidonHash> =
+            OptimalMerkleTree::default(DEFAULT_TREE_DEPTH).unwrap();
+
+        // Benchmark generate identity
+        let start_identity_gen = Date::now();
+        for _ in 0..iterations {
+            let _ = Identity::generate().unwrap();
+        }
+        let identity_gen_result = Date::now() - start_identity_gen;
+
+        // Generate identity for other benchmarks
+        let identity_pair = Identity::generate().unwrap();
+        let identity_secret = identity_pair.get_secret_hash();
+        let id_commitment = identity_pair.get_commitment();
+
+        let epoch = Hasher::hash_to_field_le(&Uint8Array::from(b"test-epoch" as &[u8])).unwrap();
+        let rln_identifier =
+            Hasher::hash_to_field_le(&Uint8Array::from(b"test-rln-identifier" as &[u8])).unwrap();
+        let external_nullifier = Hasher::poseidon_hash_pair(&epoch, &rln_identifier).unwrap();
+
+        let identity_index = tree.leaves_set();
+
+        let user_message_limit = WasmFr::from_uint(100);
+
+        let rate_commitment =
+            Hasher::poseidon_hash_pair(&id_commitment, &user_message_limit).unwrap();
+        tree.update_next(*rate_commitment).unwrap();
+
+        let message_id = WasmFr::from_uint(0);
+        let signal: [u8; 32] = [0; 32];
+        let x = Hasher::hash_to_field_le(&Uint8Array::from(&signal[..])).unwrap();
+
+        let merkle_proof: OptimalMerkleProof<PoseidonHash> = tree.proof(identity_index).unwrap();
+
+        let mut path_elements = VecWasmFr::new();
+        for path_element in merkle_proof.get_path_elements() {
+            path_elements.push(&WasmFr::from(path_element));
+        }
+        let path_index = Uint8Array::from(&merkle_proof.get_path_index()[..]);
+
+        let witness = WasmRLNWitnessInput::new(
+            &identity_secret,
+            &user_message_limit,
+            &message_id,
+            &path_elements,
+            &path_index,
+            &x,
+            &external_nullifier,
+        )
+        .unwrap();
+
+        let bigint_json = witness.to_bigint_json().unwrap();
+
+        // Benchmark witness calculation
+        let start_calculate_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = calculateWitness(CIRCOM_PATH, bigint_json.clone())
+                .await
+                .unwrap();
+        }
+        let calculate_witness_result = Date::now() - start_calculate_witness;
+
+        // Calculate witness for other benchmarks
+        let calculated_witness_str = calculateWitness(CIRCOM_PATH, bigint_json.clone())
+            .await
+            .unwrap()
+            .as_string()
+            .unwrap();
+        let calculated_witness_vec_str: Vec<String> =
+            serde_json::from_str(&calculated_witness_str).unwrap();
+        let calculated_witness: Vec<JsBigInt> = calculated_witness_vec_str
+            .iter()
+            .map(|x| JsBigInt::new(&x.into()).unwrap())
+            .collect();
+
+        // Benchmark proof generation with witness
+        let start_generate_rln_proof_with_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = rln_instance
+                .generate_rln_proof_with_witness(calculated_witness.clone(), &witness)
+                .unwrap();
+        }
+        let generate_rln_proof_with_witness_result =
+            Date::now() - start_generate_rln_proof_with_witness;
+
+        // Generate proof with witness for other benchmarks
+        let proof: WasmRLNProof = rln_instance
+            .generate_rln_proof_with_witness(calculated_witness, &witness)
+            .unwrap();
+
+        let root = WasmFr::from(tree.root());
+        let mut roots = VecWasmFr::new();
+        roots.push(&root);
+
+        // Benchmark proof verification with the root
+        let start_verify_with_roots = Date::now();
+        for _ in 0..iterations {
+            let _ = rln_instance.verify_with_roots(&proof, &roots, &x).unwrap();
+        }
+        let verify_with_roots_result = Date::now() - start_verify_with_roots;
+
+        // Verify proof with the root for other benchmarks
+        let is_proof_valid = rln_instance.verify_with_roots(&proof, &roots, &x).unwrap();
+        assert!(is_proof_valid, "verification failed");
+
+        // Format and display the benchmark results
+        let format_duration = |duration_ms: f64| -> String {
+            let avg_ms = duration_ms / (iterations as f64);
+            if avg_ms >= 1000.0 {
+                format!("{:.3} s", avg_ms / 1000.0)
+            } else {
+                format!("{:.3} ms", avg_ms)
+            }
+        };
+
+        results.push_str(&format!(
+            "RLN instance creation: {}\n",
+            format_duration(rln_new_result)
+        ));
+        results.push_str(&format!(
+            "Identity generation: {}\n",
+            format_duration(identity_gen_result)
+        ));
+        results.push_str(&format!(
+            "Witness calculation: {}\n",
+            format_duration(calculate_witness_result)
+        ));
+        results.push_str(&format!(
+            "Proof generation with witness: {}\n",
+            format_duration(generate_rln_proof_with_witness_result)
+        ));
+        results.push_str(&format!(
+            "Proof verification with roots: {}\n",
+            format_duration(verify_with_roots_result)
+        ));
+
+        // Log the results
+        console_log!("{results}");
+    }
+}

rln-wasm/tests/rln-wasm.rs

@@ -1,289 +0,0 @@
-#![cfg(target_arch = "wasm32")]
-
-#[cfg(test)]
-mod tests {
-    use js_sys::{BigInt as JsBigInt, Date, Object, Uint8Array};
-    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
-    use rln::hashers::{hash_to_field, poseidon_hash};
-    use rln::poseidon_tree::PoseidonTree;
-    use rln::protocol::{prepare_verify_input, rln_witness_from_values, serialize_witness};
-    use rln::utils::{bytes_le_to_fr, fr_to_bytes_le};
-    use rln_wasm::*;
-    use wasm_bindgen::{prelude::*, JsValue};
-    use wasm_bindgen_test::wasm_bindgen_test;
-    use zerokit_utils::merkle_tree::merkle_tree::ZerokitMerkleTree;
-
-    #[wasm_bindgen(module = "src/utils.js")]
-    extern "C" {
-        #[wasm_bindgen(catch)]
-        fn read_file(path: &str) -> Result<Uint8Array, JsValue>;
-
-        #[wasm_bindgen(catch)]
-        async fn calculateWitness(circom_path: &str, input: Object) -> Result<JsValue, JsValue>;
-    }
-
-    #[cfg(feature = "arkzkey")]
-    const ZKEY_PATH: &str = "../rln/resources/tree_height_20/rln_final.arkzkey";
-    #[cfg(not(feature = "arkzkey"))]
-    const ZKEY_PATH: &str = "../rln/resources/tree_height_20/rln_final.zkey";
-
-    const CIRCOM_PATH: &str = "../rln/resources/tree_height_20/rln.wasm";
-
-    #[wasm_bindgen_test]
-    pub async fn rln_wasm_benchmark() {
-        let mut results = String::from("\nbenchmarks:\n");
-        let iterations = 10;
-
-        let zkey = read_file(&ZKEY_PATH).expect("Failed to read zkey file");
-
-        // Benchmark wasm_new
-        let start_wasm_new = Date::now();
-        for _ in 0..iterations {
-            let _ = wasm_new(zkey.clone()).expect("Failed to create RLN instance");
-        }
-        let wasm_new_result = Date::now() - start_wasm_new;
-
-        // Create RLN instance for other benchmarks
-        let rln_instance = wasm_new(zkey).expect("Failed to create RLN instance");
-        let mut tree = PoseidonTree::default(TEST_TREE_HEIGHT).expect("Failed to create tree");
-
-        // Benchmark wasm_key_gen
-        let start_wasm_key_gen = Date::now();
-        for _ in 0..iterations {
-            let _ = wasm_key_gen(rln_instance).expect("Failed to generate keys");
-        }
-        let wasm_key_gen_result = Date::now() - start_wasm_key_gen;
-
-        // Generate identity pair for other benchmarks
-        let mem_keys = wasm_key_gen(rln_instance).expect("Failed to generate keys");
-        let id_key = mem_keys.subarray(0, 32);
-        let (identity_secret_hash, _) = bytes_le_to_fr(&id_key.to_vec());
-        let (id_commitment, _) = bytes_le_to_fr(&mem_keys.subarray(32, 64).to_vec());
-
-        let epoch = hash_to_field(b"test-epoch");
-        let rln_identifier = hash_to_field(b"test-rln-identifier");
-        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
-
-        let identity_index = tree.leaves_set();
-
-        let user_message_limit = Fr::from(100);
-
-        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
-        tree.update_next(rate_commitment)
-            .expect("Failed to update tree");
-
-        let message_id = Fr::from(0);
-        let signal: [u8; 32] = [0; 32];
-        let x = hash_to_field(&signal);
-
-        let merkle_proof = tree
-            .proof(identity_index)
-            .expect("Failed to generate merkle proof");
-
-        let rln_witness = rln_witness_from_values(
-            identity_secret_hash,
-            &merkle_proof,
-            x,
-            external_nullifier,
-            user_message_limit,
-            message_id,
-        )
-        .expect("Failed to create RLN witness");
-
-        let serialized_witness =
-            serialize_witness(&rln_witness).expect("Failed to serialize witness");
-        let witness_buffer = Uint8Array::from(&serialized_witness[..]);
-
-        let json_inputs = wasm_rln_witness_to_json(rln_instance, witness_buffer.clone())
-            .expect("Failed to convert witness to JSON");
-
-        // Benchmark calculateWitness
-        let start_calculate_witness = Date::now();
-        for _ in 0..iterations {
-            let _ = calculateWitness(&CIRCOM_PATH, json_inputs.clone())
-                .await
-                .expect("Failed to calculate witness");
-        }
-        let calculate_witness_result = Date::now() - start_calculate_witness;
-
-        // Calculate witness for other benchmarks
-        let calculated_witness_json = calculateWitness(&CIRCOM_PATH, json_inputs)
-            .await
-            .expect("Failed to calculate witness")
-            .as_string()
-            .expect("Failed to convert calculated witness to string");
-        let calculated_witness_vec_str: Vec<String> =
-            serde_json::from_str(&calculated_witness_json).expect("Failed to parse JSON");
-        let calculated_witness: Vec<JsBigInt> = calculated_witness_vec_str
-            .iter()
-            .map(|x| JsBigInt::new(&x.into()).expect("Failed to create JsBigInt"))
-            .collect();
-
-        // Benchmark wasm_generate_rln_proof_with_witness
-        let start_wasm_generate_rln_proof_with_witness = Date::now();
-        for _ in 0..iterations {
-            let _ = wasm_generate_rln_proof_with_witness(
-                rln_instance,
-                calculated_witness.clone(),
-                witness_buffer.clone(),
-            )
-            .expect("Failed to generate proof");
-        }
-        let wasm_generate_rln_proof_with_witness_result =
-            Date::now() - start_wasm_generate_rln_proof_with_witness;
-
-        // Generate a proof for other benchmarks
-        let proof =
-            wasm_generate_rln_proof_with_witness(rln_instance, calculated_witness, witness_buffer)
-                .expect("Failed to generate proof");
-
-        let proof_data = proof.to_vec();
-        let verify_input = prepare_verify_input(proof_data, &signal);
-        let input_buffer = Uint8Array::from(&verify_input[..]);
-
-        let root = tree.root();
-        let roots_serialized = fr_to_bytes_le(&root);
-        let roots_buffer = Uint8Array::from(&roots_serialized[..]);
-
-        // Benchmark wasm_verify_with_roots
-        let start_wasm_verify_with_roots = Date::now();
-        for _ in 0..iterations {
-            let _ =
-                wasm_verify_with_roots(rln_instance, input_buffer.clone(), roots_buffer.clone())
-                    .expect("Failed to verify proof");
-        }
-        let wasm_verify_with_roots_result = Date::now() - start_wasm_verify_with_roots;
-
-        // Verify the proof with the root
-        let is_proof_valid = wasm_verify_with_roots(rln_instance, input_buffer, roots_buffer)
-            .expect("Failed to verify proof");
-        assert!(is_proof_valid, "verification failed");
-
-        // Format and display results
-        let format_duration = |duration_ms: f64| -> String {
-            let avg_ms = duration_ms / (iterations as f64);
-            if avg_ms >= 1000.0 {
-                format!("{:.3} s", avg_ms / 1000.0)
-            } else {
-                format!("{:.3} ms", avg_ms)
-            }
-        };
-
-        results.push_str(&format!("wasm_new: {}\n", format_duration(wasm_new_result)));
-        results.push_str(&format!(
-            "wasm_key_gen: {}\n",
-            format_duration(wasm_key_gen_result)
-        ));
-        results.push_str(&format!(
-            "calculateWitness: {}\n",
-            format_duration(calculate_witness_result)
-        ));
-        results.push_str(&format!(
-            "wasm_generate_rln_proof_with_witness: {}\n",
-            format_duration(wasm_generate_rln_proof_with_witness_result)
-        ));
-        results.push_str(&format!(
-            "wasm_verify_with_roots: {}\n",
-            format_duration(wasm_verify_with_roots_result)
-        ));
-
-        // Log the results
-        wasm_bindgen_test::console_log!("{results}");
-    }
-
-    #[wasm_bindgen_test]
-    pub async fn rln_wasm_test() {
-        // Read the zkey file
-        let zkey = read_file(&ZKEY_PATH).expect("Failed to read zkey file");
-
-        // Create RLN instance and separated tree
-        let rln_instance = wasm_new(zkey).expect("Failed to create RLN instance");
-        let mut tree = PoseidonTree::default(TEST_TREE_HEIGHT).expect("Failed to create tree");
-
-        // Setting up the epoch and rln_identifier
-        let epoch = hash_to_field(b"test-epoch");
-        let rln_identifier = hash_to_field(b"test-rln-identifier");
-        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
-
-        // Generate identity pair
-        let mem_keys = wasm_key_gen(rln_instance).expect("Failed to generate keys");
-        let (identity_secret_hash, _) = bytes_le_to_fr(&mem_keys.subarray(0, 32).to_vec());
-        let (id_commitment, _) = bytes_le_to_fr(&mem_keys.subarray(32, 64).to_vec());
-
-        // Get index of the identity
-        let identity_index = tree.leaves_set();
-
-        // Setting up the user message limit
-        let user_message_limit = Fr::from(100);
-
-        // Updating the tree with the rate commitment
-        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
-        tree.update_next(rate_commitment)
-            .expect("Failed to update tree");
-
-        // Generate merkle proof
-        let merkle_proof = tree
-            .proof(identity_index)
-            .expect("Failed to generate merkle proof");
-
-        // Create message id and signal
-        let message_id = Fr::from(0);
-        let signal: [u8; 32] = [0; 32];
-        let x = hash_to_field(&signal);
-
-        // Prepare input for witness calculation
-        let rln_witness = rln_witness_from_values(
-            identity_secret_hash,
-            &merkle_proof,
-            x,
-            external_nullifier,
-            user_message_limit,
-            message_id,
-        )
-        .expect("Failed to create RLN witness");
-
-        // Serialize the rln witness
-        let serialized_witness =
-            serialize_witness(&rln_witness).expect("Failed to serialize witness");
-        // Convert the serialized witness to a Uint8Array
-        let witness_buffer = Uint8Array::from(&serialized_witness[..]);
-
-        // Obtaining inputs that should be sent to circom witness calculator
-        let json_inputs = wasm_rln_witness_to_json(rln_instance, witness_buffer.clone())
-            .expect("Failed to convert witness to JSON");
-
-        // Calculating witness with JS
-        // (Using a JSON since wasm_bindgen does not like Result<Vec<JsBigInt>,JsValue>)
-        let calculated_witness_json = calculateWitness(&CIRCOM_PATH, json_inputs)
-            .await
-            .expect("Failed to calculate witness")
-            .as_string()
-            .expect("Failed to convert calculated witness to string");
-        let calculated_witness_vec_str: Vec<String> =
-            serde_json::from_str(&calculated_witness_json).expect("Failed to parse JSON");
-        let calculated_witness: Vec<JsBigInt> = calculated_witness_vec_str
-            .iter()
-            .map(|x| JsBigInt::new(&x.into()).expect("Failed to create JsBigInt"))
-            .collect();
-
-        // Generate a proof from the calculated witness
-        let proof =
-            wasm_generate_rln_proof_with_witness(rln_instance, calculated_witness, witness_buffer)
-                .expect("Failed to generate proof");
-
-        // Prepare the root for verification
-        let root = tree.root();
-        let roots_serialized = fr_to_bytes_le(&root);
-        let roots_buffer = Uint8Array::from(&roots_serialized[..]);
-
-        // Prepare input for proof verification
-        let proof_data = proof.to_vec();
-        let verify_input = prepare_verify_input(proof_data, &signal);
-        let input_buffer = Uint8Array::from(&verify_input[..]);
-
-        // Verify the proof with the root
-        let is_proof_valid = wasm_verify_with_roots(rln_instance, input_buffer, roots_buffer)
-            .expect("Failed to verify proof");
-        assert!(is_proof_valid, "verification failed");
-    }
-}

rln-wasm/tests/utils.rs

@@ -0,0 +1,222 @@
+#![cfg(target_arch = "wasm32")]
+
+#[cfg(test)]
+mod test {
+    use std::assert_eq;
+
+    use ark_std::rand::thread_rng;
+    use js_sys::Uint8Array;
+    use rand::Rng;
+    use rln::prelude::*;
+    use rln_wasm::{ExtendedIdentity, Hasher, Identity, VecWasmFr, WasmFr};
+    use wasm_bindgen_test::wasm_bindgen_test;
+
+    #[wasm_bindgen_test]
+    fn test_keygen_wasm() {
+        let identity = Identity::generate().unwrap();
+        let identity_secret = *identity.get_secret_hash();
+        let id_commitment = *identity.get_commitment();
+
+        assert_ne!(identity_secret, Fr::from(0u8));
+        assert_ne!(id_commitment, Fr::from(0u8));
+
+        let arr = identity.to_array();
+        assert_eq!(arr.length(), 2);
+        assert_eq!(*arr.get(0).unwrap(), identity_secret);
+        assert_eq!(*arr.get(1).unwrap(), id_commitment);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_extended_keygen_wasm() {
+        let identity = ExtendedIdentity::generate().unwrap();
+
+        let identity_trapdoor = *identity.get_trapdoor();
+        let identity_nullifier = *identity.get_nullifier();
+        let identity_secret = *identity.get_secret_hash();
+        let id_commitment = *identity.get_commitment();
+
+        assert_ne!(identity_trapdoor, Fr::from(0u8));
+        assert_ne!(identity_nullifier, Fr::from(0u8));
+        assert_ne!(identity_secret, Fr::from(0u8));
+        assert_ne!(id_commitment, Fr::from(0u8));
+
+        let arr = identity.to_array();
+        assert_eq!(arr.length(), 4);
+        assert_eq!(*arr.get(0).unwrap(), identity_trapdoor);
+        assert_eq!(*arr.get(1).unwrap(), identity_nullifier);
+        assert_eq!(*arr.get(2).unwrap(), identity_secret);
+        assert_eq!(*arr.get(3).unwrap(), id_commitment);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_seeded_keygen_wasm() {
+        let seed_bytes: Vec<u8> = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+        let seed = Uint8Array::from(&seed_bytes[..]);
+
+        let identity = Identity::generate_seeded(&seed).unwrap();
+        let identity_secret = *identity.get_secret_hash();
+        let id_commitment = *identity.get_commitment();
+
+        let expected_identity_secret_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        )
+        .unwrap();
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0xbf16d2b5c0d6f9d9d561e05bfca16a81b4b873bb063508fae360d8c74cef51f",
+            16,
+        )
+        .unwrap();
+
+        assert_eq!(identity_secret, expected_identity_secret_seed_bytes);
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_seeded_extended_keygen_wasm() {
+        let seed_bytes: Vec<u8> = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+        let seed = Uint8Array::from(&seed_bytes[..]);
+
+        let identity = ExtendedIdentity::generate_seeded(&seed).unwrap();
+
+        let identity_trapdoor = *identity.get_trapdoor();
+        let identity_nullifier = *identity.get_nullifier();
+        let identity_secret = *identity.get_secret_hash();
+        let id_commitment = *identity.get_commitment();
+
+        let expected_identity_trapdoor_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        )
+        .unwrap();
+        let expected_identity_nullifier_seed_bytes = str_to_fr(
+            "0x1f18714c7bc83b5bca9e89d404cf6f2f585bc4c0f7ed8b53742b7e2b298f50b4",
+            16,
+        )
+        .unwrap();
+        let expected_identity_secret_seed_bytes = str_to_fr(
+            "0x2aca62aaa7abaf3686fff2caf00f55ab9462dc12db5b5d4bcf3994e671f8e521",
+            16,
+        )
+        .unwrap();
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0x68b66aa0a8320d2e56842581553285393188714c48f9b17acd198b4f1734c5c",
+            16,
+        )
+        .unwrap();
+
+        assert_eq!(identity_trapdoor, expected_identity_trapdoor_seed_bytes);
+        assert_eq!(identity_nullifier, expected_identity_nullifier_seed_bytes);
+        assert_eq!(identity_secret, expected_identity_secret_seed_bytes);
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_wasmfr() {
+        let wasmfr_zero = WasmFr::zero();
+        let fr_zero = Fr::from(0u8);
+        assert_eq!(*wasmfr_zero, fr_zero);
+
+        let wasmfr_one = WasmFr::one();
+        let fr_one = Fr::from(1u8);
+        assert_eq!(*wasmfr_one, fr_one);
+
+        let wasmfr_int = WasmFr::from_uint(42);
+        let fr_int = Fr::from(42u8);
+        assert_eq!(*wasmfr_int, fr_int);
+
+        let wasmfr_debug_str = wasmfr_int.debug();
+        assert_eq!(wasmfr_debug_str.to_string(), "42");
+
+        let identity = Identity::generate().unwrap();
+        let mut id_secret_fr = *identity.get_secret_hash();
+        let id_secret_hash = IdSecret::from(&mut id_secret_fr);
+        let id_commitment = *identity.get_commitment();
+        let wasmfr_id_secret_hash = *identity.get_secret_hash();
+        assert_eq!(wasmfr_id_secret_hash, *id_secret_hash);
+        let wasmfr_id_commitment = *identity.get_commitment();
+        assert_eq!(wasmfr_id_commitment, id_commitment);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_vec_wasmfr() {
+        let vec_fr = vec![Fr::from(1u8), Fr::from(2u8), Fr::from(3u8), Fr::from(4u8)];
+        let mut vec_wasmfr = VecWasmFr::new();
+        for fr in &vec_fr {
+            vec_wasmfr.push(&WasmFr::from(*fr));
+        }
+
+        let bytes_le = vec_wasmfr.to_bytes_le();
+        let expected_le = rln::utils::vec_fr_to_bytes_le(&vec_fr);
+        assert_eq!(bytes_le.to_vec(), expected_le);
+
+        let bytes_be = vec_wasmfr.to_bytes_be();
+        let expected_be = rln::utils::vec_fr_to_bytes_be(&vec_fr);
+        assert_eq!(bytes_be.to_vec(), expected_be);
+
+        let vec_wasmfr_from_le = match VecWasmFr::from_bytes_le(&bytes_le) {
+            Ok(v) => v,
+            Err(err) => panic!("VecWasmFr::from_bytes_le call failed: {}", err),
+        };
+        assert_eq!(vec_wasmfr_from_le.length(), vec_wasmfr.length());
+        for i in 0..vec_wasmfr.length() {
+            assert_eq!(
+                *vec_wasmfr_from_le.get(i).unwrap(),
+                *vec_wasmfr.get(i).unwrap()
+            );
+        }
+
+        let vec_wasmfr_from_be = match VecWasmFr::from_bytes_be(&bytes_be) {
+            Ok(v) => v,
+            Err(err) => panic!("VecWasmFr::from_bytes_be call failed: {}", err),
+        };
+        for i in 0..vec_wasmfr.length() {
+            assert_eq!(
+                *vec_wasmfr_from_be.get(i).unwrap(),
+                *vec_wasmfr.get(i).unwrap()
+            );
+        }
+    }
+
+    #[wasm_bindgen_test]
+    fn test_hash_to_field_wasm() {
+        let mut rng = thread_rng();
+        let signal_gen: [u8; 32] = rng.gen();
+        let signal = Uint8Array::from(&signal_gen[..]);
+
+        let wasmfr_le_1 = Hasher::hash_to_field_le(&signal).unwrap();
+        let fr_le_2 = hash_to_field_le(&signal_gen).unwrap();
+        assert_eq!(*wasmfr_le_1, fr_le_2);
+
+        let wasmfr_be_1 = Hasher::hash_to_field_be(&signal).unwrap();
+        let fr_be_2 = hash_to_field_be(&signal_gen).unwrap();
+        assert_eq!(*wasmfr_be_1, fr_be_2);
+
+        assert_eq!(*wasmfr_le_1, *wasmfr_be_1);
+        assert_eq!(fr_le_2, fr_be_2);
+
+        let hash_wasmfr_le_1 = wasmfr_le_1.to_bytes_le();
+        let hash_fr_le_2 = fr_to_bytes_le(&fr_le_2);
+        assert_eq!(hash_wasmfr_le_1.to_vec(), hash_fr_le_2);
+
+        let hash_wasmfr_be_1 = wasmfr_be_1.to_bytes_be();
+        let hash_fr_be_2 = fr_to_bytes_be(&fr_be_2);
+        assert_eq!(hash_wasmfr_be_1.to_vec(), hash_fr_be_2);
+
+        assert_ne!(hash_wasmfr_le_1.to_vec(), hash_wasmfr_be_1.to_vec());
+        assert_ne!(hash_fr_le_2, hash_fr_be_2);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_poseidon_hash_pair_wasm() {
+        let input_1 = Fr::from(42u8);
+        let input_2 = Fr::from(99u8);
+
+        let expected_hash = poseidon_hash(&[input_1, input_2]).unwrap();
+        let wasmfr_1 = WasmFr::from_uint(42);
+        let wasmfr_2 = WasmFr::from_uint(99);
+        let received_hash = Hasher::poseidon_hash_pair(&wasmfr_1, &wasmfr_2).unwrap();
+
+        assert_eq!(*received_hash, expected_hash);
+    }
+}

rln/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rln"
-version = "0.7.0"
+version = "1.0.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
@@ -9,88 +9,81 @@ homepage = "https://vac.dev"
 repository = "https://github.com/vacp2p/zerokit"
 
 [lib]
-crate-type = ["rlib", "staticlib"]
+crate-type = ["rlib", "staticlib", "cdylib"]
 bench = false
 
-# This flag disable cargo doctests, i.e. testing example code-snippets in documentation
+# This flag disables cargo doctests, i.e. testing example code-snippets in documentation
 doctest = false
 
 [dependencies]
 # ZKP Generation
 ark-bn254 = { version = "0.5.0", features = ["std"] }
 ark-relations = { version = "0.5.1", features = ["std"] }
-ark-ff = { version = "0.5.0", default-features = false, features = [
-    "parallel",
-] }
-ark-ec = { version = "0.5.0", default-features = false, features = [
-    "parallel",
-] }
+ark-ff = { version = "0.5.0", default-features = false }
+ark-ec = { version = "0.5.0", default-features = false }
+ark-std = { version = "0.5.0", default-features = false }
+ark-poly = { version = "0.5.0", default-features = false }
+ark-groth16 = { version = "0.5.0", default-features = false }
+ark-serialize = { version = "0.5.0", default-features = false }
 
-ark-std = { version = "0.5.0", default-features = false, features = [
-    "parallel",
-] }
-ark-poly = { version = "0.5.0", default-features = false, features = [
-    "parallel",
-] }
-ark-groth16 = { version = "0.5.0", default-features = false, features = [
-    "parallel",
-] }
-ark-serialize = { version = "0.5.0", default-features = false, features = [
-    "parallel",
-] }
+# Error Handling
+thiserror = "2.0.17"
 
-# error handling
-color-eyre = "0.6.3"
-thiserror = "2.0.12"
-
-# utilities
+# Utilities
+rayon = { version = "1.11.0", optional = true }
 byteorder = "1.5.0"
-cfg-if = "1.0"
-num-bigint = { version = "0.4.6", default-features = false, features = [
-    "rand",
-    "std",
-] }
+cfg-if = "1.0.4"
+num-bigint = { version = "0.4.6", default-features = false, features = ["std"] }
 num-traits = "0.2.19"
 once_cell = "1.21.3"
-lazy_static = "1.5.0"
 rand = "0.8.5"
 rand_chacha = "0.3.1"
-ruint = { version = "1.14.0", features = ["rand", "serde", "ark-ff-04"] }
+ruint = { version = "1.17.0", default-features = false, features = [
+    "rand",
+    "serde",
+    "ark-ff-05",
+] }
 tiny-keccak = { version = "2.0.2", features = ["keccak"] }
-utils = { package = "zerokit_utils", version = "0.5.2", path = "../utils", default-features = false }
+zeroize = "1.8.2"
+tempfile = "3.23.0"
+zerokit_utils = { version = "1.0.0", path = "../utils", default-features = false }
 
-# serialization
-prost = "0.13.5"
-serde_json = "1.0"
-serde = { version = "1.0", features = ["derive"] }
+# FFI
+safer-ffi.version = "0.1"
 
-document-features = { version = "0.2.11", optional = true }
+# Serialization
+prost = "0.14.1"
+serde_json = "1.0.145"
+serde = { version = "1.0.228", features = ["derive"] }
+
+# Documentation
+document-features = { version = "0.2.12", optional = true }
 
 [dev-dependencies]
-sled = "0.34.7"
-criterion = { version = "0.4.0", features = ["html_reports"] }
+criterion = { version = "0.8.0", features = ["html_reports"] }
 
 [features]
-default = ["pmtree-ft"]
-fullmerkletree = ["default"]
+default = ["parallel", "pmtree-ft"]
 stateless = []
-arkzkey = []
-
-# Note: pmtree feature is still experimental
-pmtree-ft = ["utils/pmtree-ft"]
-
-[[bench]]
-name = "circuit_loading_arkzkey_benchmark"
-harness = false
-required-features = ["arkzkey"]
-
-[[bench]]
-name = "circuit_loading_benchmark"
-harness = false
+parallel = [
+    "rayon",
+    "ark-ff/parallel",
+    "ark-ec/parallel",
+    "ark-std/parallel",
+    "ark-poly/parallel",
+    "ark-groth16/parallel",
+    "ark-serialize/parallel",
+    "zerokit_utils/parallel",
+]
+fullmerkletree = [] # Pre-allocated tree, fastest access
+optimalmerkletree = [] # Sparse storage, memory efficient
+pmtree-ft = ["zerokit_utils/pmtree-ft"] # Persistent storage, disk-based
+headers = ["safer-ffi/headers"] # Generate C header file with safer-ffi
 
 [[bench]]
 name = "pmtree_benchmark"
 harness = false
+required-features = ["pmtree-ft"]
 
 [[bench]]
 name = "poseidon_tree_benchmark"
@@ -98,3 +91,7 @@ harness = false
 
 [package.metadata.docs.rs]
 all-features = true
+
+[[bin]]
+name = "generate-headers"
+required-features = ["headers"] # Do not build unless generating headers.

rln/Makefile.toml

@@ -8,11 +8,15 @@ args = ["test", "--release", "--", "--nocapture"]
 
 [tasks.test_stateless]
 command = "cargo"
-args = ["test", "--release", "--features", "stateless"]
-
-[tasks.test_arkzkey]
-command = "cargo"
-args = ["test", "--release", "--features", "arkzkey"]
+args = [
+	"test",
+	"--release",
+	"--no-default-features",
+	"--features",
+	"stateless",
+	"--",
+	"--nocapture",
+]
 
 [tasks.bench]
 command = "cargo"

rln/README.md

@@ -1,8 +1,12 @@
 # Zerokit RLN Module
 
 [![Crates.io](https://img.shields.io/crates/v/rln.svg)](https://crates.io/crates/rln)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 
-The Zerokit RLN Module provides a Rust implementation for working with Rate-Limiting Nullifier [RLN](https://rfc.vac.dev/spec/32/) zkSNARK proofs and primitives. This module allows you to:
+The Zerokit RLN Module provides a Rust implementation for working with
+Rate-Limiting Nullifier [RLN](https://rfc.vac.dev/vac/raw/rln-v2) zkSNARK proofs and primitives.
+This module allows you to:
 
 - Generate and verify RLN proofs
 - Work with Merkle trees for commitment storage
@@ -11,7 +15,8 @@ The Zerokit RLN Module provides a Rust implementation for working with Rate-Limi
 ## Quick Start
 
 > [!IMPORTANT]
-> Version 0.6.1 is required for WASM support or x32 architecture. Current version doesn't support these platforms due to dependency issues. WASM support will return in a future release.
+> Version 0.7.0 is the only version that does not support WASM and x32 architecture.
+> WASM support is available in version 0.8.0 and above.
 
 ### Add RLN as dependency
 
@@ -19,110 +24,104 @@ We start by adding zerokit RLN to our `Cargo.toml`
 
 ```toml
 [dependencies]
-rln = { git = "https://github.com/vacp2p/zerokit" }
+rln = "1.0.0"
 ```
 
 ## Basic Usage Example
 
-Note that we need to pass to RLN object constructor the path where the graph file (`graph.bin`, built for the input tree size), the corresponding proving key (`rln_final.zkey`) or (`rln_final_uncompr.arkzkey`) and verification key (`verification_key.arkvkey`, optional) are found.
+The RLN object constructor requires the following files:
 
-In the following we will use [cursors](https://doc.rust-lang.org/std/io/struct.Cursor.html) as readers/writers for interfacing with RLN public APIs.
+- `rln_final.arkzkey`: The proving key in arkzkey format.
+- `graph.bin`: The graph file built for the input tree size
+
+Additionally, `rln.wasm` is used for testing in the rln-wasm module.
 
 ```rust
-use std::io::Cursor;
-
-use rln::{
-    circuit::Fr,
-    hashers::{hash_to_field, poseidon_hash},
-    protocol::{keygen, prepare_prove_input, prepare_verify_input},
-    public::RLN,
-    utils::fr_to_bytes_le,
-};
-use serde_json::json;
+use rln::prelude::{keygen, poseidon_hash, hash_to_field_le, RLN, RLNWitnessInput, Fr, IdSecret};
 
 fn main() {
     // 1. Initialize RLN with parameters:
-    // - the tree height;
+    // - the tree depth;
     // - the tree config, if it is not defined, the default value will be set
-    let tree_height = 20;
-    let input = Cursor::new(json!({}).to_string());
-    let mut rln = RLN::new(tree_height, input).unwrap();
+    let tree_depth = 20;
+    let mut rln = RLN::new(tree_depth, "").unwrap();
 
     // 2. Generate an identity keypair
-    let (identity_secret_hash, id_commitment) = keygen();
+    let (identity_secret, id_commitment) = keygen();
 
     // 3. Add a rate commitment to the Merkle tree
-    let id_index = 10;
+    let leaf_index = 10;
     let user_message_limit = Fr::from(10);
     let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
-    let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
-    rln.set_leaf(id_index, &mut buffer).unwrap();
+    rln.set_leaf(leaf_index, rate_commitment).unwrap();
 
-    // 4. Set up external nullifier (epoch + app identifier)
+    // 4. Get the Merkle proof for the added commitment
+    let (path_elements, identity_path_index) = rln.get_merkle_proof(leaf_index).unwrap();
+
+    // 5. Set up external nullifier (epoch + app identifier)
     // We generate epoch from a date seed and we ensure is
     // mapped to a field element by hashing-to-field its content
-    let epoch = hash_to_field(b"Today at noon, this year");
-    // We generate rln_identifier from a date seed and we ensure is
-    // mapped to a field element by hashing-to-field its content
-    let rln_identifier = hash_to_field(b"test-rln-identifier");
+    let epoch = hash_to_field_le(b"Today at noon, this year");
+    // We generate rln_identifier from an application identifier and
+    // we ensure is mapped to a field element by hashing-to-field its content
+    let rln_identifier = hash_to_field_le(b"test-rln-identifier");
     // We generate a external nullifier
     let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
     // We choose a message_id satisfy 0 <= message_id < user_message_limit
     let message_id = Fr::from(1);
 
-    // 5. Generate and verify a proof for a message
+    // 6. Define the message signal
     let signal = b"RLN is awesome";
 
-    // 6. Prepare input for generate_rln_proof API
-    // input_data is [ identity_secret<32> | id_index<8> | external_nullifier<32> | user_message_limit<32> | message_id<32> | signal_len<8> | signal<var> ]
-    let prove_input = prepare_prove_input(
-        identity_secret_hash,
-        id_index,
+    // 7. Compute x from the signal
+    let x = hash_to_field_le(signal);
+
+    // 8. Create witness input for RLN proof generation
+    let witness = RLNWitnessInput::new(
+        identity_secret,
         user_message_limit,
         message_id,
+        path_elements,
+        identity_path_index,
+        x,
         external_nullifier,
-        signal,
-    );
-
-    // 7. Generate a RLN proof
-    // We generate a RLN proof for proof_input
-    let mut input_buffer = Cursor::new(prove_input);
-    let mut output_buffer = Cursor::new(Vec::<u8>::new());
-    rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
+    )
     .unwrap();
 
-    // We get the public outputs returned by the circuit evaluation
-    // The byte vector `proof_data` is serialized as `[ zk-proof | tree_root | external_nullifier | share_x | share_y | nullifier ]`.
-    let proof_data = output_buffer.into_inner();
+    // 9. Generate a RLN proof
+    // We generate proof and proof values from the witness
+    let (proof, proof_values) = rln.generate_rln_proof(&witness).unwrap();
 
-    // 8. Verify a RLN proof
-    // Input buffer is serialized as `[proof_data | signal_len | signal ]`, where `proof_data` is (computed as) the output obtained by `generate_rln_proof`.
-    let verify_data = prepare_verify_input(proof_data, signal);
-
-    // We verify the zk-proof against the provided proof values
-    let mut input_buffer = Cursor::new(verify_data);
-    let verified = rln.verify_rln_proof(&mut input_buffer).unwrap();
-
-    // We ensure the proof is valid
+    // 10. Verify the RLN proof
+    // We verify the proof using the proof and proof values and the hashed signal x
+    let verified = rln.verify_rln_proof(&proof, &proof_values, &x).unwrap();
     assert!(verified);
 }
 ```
 
-### Comments for the code above for point 4
+### Comments for the code above for point 5
 
 The `external nullifier` includes two parameters.
 
 The first one is `epoch` and it's used to identify messages received in a certain time frame.
-It usually corresponds to the current UNIX time but can also be set to a random value or generated by a seed, provided that it corresponds to a field element.
+It usually corresponds to the current UNIX time but can also be set to a random value or generated by a seed,
+provided that it corresponds to a field element.
 
-The second one is `rln_identifier` and it's used to prevent a RLN ZK proof generated for one application to be re-used in another one.
+The second one is `rln_identifier` and it's used to prevent a RLN ZK proof generated
+for one application to be re-used in another one.
 
 ### Features
 
-- **Multiple Backend Support**: Choose between different zkey formats with feature flags
-  - `arkzkey`: Use the optimized Arkworks-compatible zkey format (faster loading)
-  - `stateless`: For stateless proof verification
-- **Pre-compiled Circuits**: Ready-to-use circuits with Merkle tree height of 20
+- **Stateless Mode**: Allows the use of RLN without maintaining state of the Merkle tree.
+- **Pre-compiled Circuits**: Ready-to-use circuits with Merkle tree depth of 20
+- **Wasm Support**: WebAssembly bindings via rln-wasm crate with features like:
+  - Browser and Node.js compatibility
+  - Optional parallel feature support using [wasm-bindgen-rayon](https://github.com/RReverser/wasm-bindgen-rayon)
+  - Headless browser testing capabilities
+- **Merkle Tree Implementations**: Multiple tree variants optimized for different use cases:
+  - **Full Merkle Tree**: Fastest access with complete pre-allocated tree in memory. Best for frequent random access (enable with `fullmerkletree` feature).
+  - **Optimal Merkle Tree**: Memory-efficient sparse storage using HashMap. Ideal for partially populated trees (enable with `optimalmerkletree` feature).
+  - **Persistent Merkle Tree**: Disk-based storage with [sled](https://github.com/spacejam/sled) for persistence across application restarts and large datasets (enable with `pmtree-ft` feature).
 
 ## Building and Testing
 
@@ -143,20 +142,22 @@ cargo make build
 # Test with default features
 cargo make test
 
-# Test with specific features
-cargo make test_arkzkey    # For arkzkey feature
-cargo make test_stateless  # For stateless feature
+# Test with stateless features
+cargo make test_stateless
 ```
 
 ## Advanced: Custom Circuit Compilation
 
-The `rln` (<https://github.com/rate-limiting-nullifier/circom-rln>) repository, which contains the RLN circuit implementation is using for pre-compiled RLN circuit for zerokit RLN.
+The `circom-rln` (<https://github.com/rate-limiting-nullifier/circom-rln>) repository,
+which contains the RLN circuit implementation used for pre-compiled RLN circuit for zerokit RLN.
 If you want to compile your own RLN circuit, you can follow the instructions below.
 
-### 1. Compile ZK Circuits for getting the zkey and verification key files
+### 1. Compile ZK Circuits for getting the zkey file
 
-This script actually generates not only the zkey and verification key files for the RLN circuit, but also the execution wasm file used for witness calculation.
-However, the wasm file is not needed for the `rln` module, because current implementation uses the iden3 graph file for witness calculation.
+This script actually generates not only the zkey file for the RLN circuit,
+but also the execution wasm file used for witness calculation.
+However, the wasm file is not needed for the `rln` module,
+because current implementation uses the iden3 graph file for witness calculation.
 This graph file is generated by the `circom-witnesscalc` tool in [step 2](#2-generate-witness-calculation-graph).
 
 To customize the circuit parameters, modify `circom-rln/circuits/rln.circom`:
@@ -169,19 +170,27 @@ component main { public [x, externalNullifier] } = RLN(N, M);
 
 Where:
 
-- `N`: Merkle tree height, determining the maximum membership capacity (2^N members).
+- `N`: Merkle tree depth, determining the maximum membership capacity (2^N members).
 
 - `M`: Bit size for range checks, setting an upper bound for the number of messages per epoch (2^M messages).
 
 > [!NOTE]
-> However, if `N` is too big, this might require a larger Powers of Tau ceremony than the one hardcoded in `./scripts/build-circuits.sh`, which is `2^14`. \
-> In such case, we refer to the official [Circom documentation](https://docs.circom.io/getting-started/proving-circuits/#powers-of-tau) for instructions on how to run an appropriate Powers of Tau ceremony and Phase 2 in order to compile the desired circuit. \
-> Additionally, while `M` sets an upper bound on the number of messages per epoch (`2^M`), you can configure lower message limit for your use case, as long as it satisfies `user_message_limit ≤ 2^M`. \
-> Currently, the `rln` module comes with a [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) RLN circuit with a Merkle tree of height `20` and a bit size of `16`, allowing up to `2^20` registered members and a `2^16` message limit per epoch.
+> However, if `N` is too big, this might require a larger Powers of Tau ceremony
+> than the one hardcoded in `./scripts/build-circuits.sh`, which is `2^14`.
+> In such case, we refer to the official
+> [Circom documentation](https://docs.circom.io/getting-started/proving-circuits/#powers-of-tau)
+> for instructions on how to run an appropriate Powers of Tau ceremony and Phase 2 in order to compile the desired circuit. \
+> Additionally, while `M` sets an upper bound on the number of messages per epoch (`2^M`),
+> you can configure lower message limit for your use case, as long as it satisfies `user_message_limit ≤ 2^M`. \
+> Currently, the `rln` module comes with a [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources/tree_depth_20)
+> RLN circuit with a Merkle tree of depth `20` and a bit size of `16`,
+> allowing up to `2^20` registered members and a `2^16` message limit per epoch.
 
 #### Install circom compiler
 
-You can follow the instructions below or refer to the [installing Circom](https://docs.circom.io/getting-started/installation/#installing-circom) guide for more details, but make sure to use the specific version `v2.1.0`.
+You can follow the instructions below or refer to the
+[installing Circom](https://docs.circom.io/getting-started/installation/#installing-circom) guide for more details.
+Make sure to use the specific version `v2.1.0`.
 
 ```sh
 # Clone the circom repository
@@ -218,7 +227,8 @@ cp zkeyFiles/rln/final.zkey <path_to_rln_final.zkey>
 
 ### 2. Generate Witness Calculation Graph
 
-The execution graph file used for witness calculation can be compiled following instructions in the [circom-witnesscalc](https://github.com/iden3/circom-witnesscalc) repository.
+The execution graph file used for witness calculation can be compiled following instructions
+in the [circom-witnesscalc](https://github.com/iden3/circom-witnesscalc) repository.
 As mentioned in step 1, we should use `rln.circom` file from `circom-rln` repository.
 
 ```sh
@@ -235,11 +245,14 @@ cargo build
 cargo run --package circom_witnesscalc --bin build-circuit ../circom-rln/circuits/rln.circom <path_to_graph.bin>
 ```
 
-The `rln` module comes with [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) execution graph files for the RLN circuit.
+The `rln` module comes with [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources/tree_depth_20)
+execution graph files for the RLN circuit.
 
-### 3. Generate Arkzkey Representation for zkey and verification key files
+### 3. Generate Arkzkey Representation for zkey file
 
-For faster loading, compile the zkey file into the arkzkey format using [ark-zkey](https://github.com/seemenkina/ark-zkey). This is fork of the [original](https://github.com/zkmopro/ark-zkey) repository with the uncompressed zkey support.
+For faster loading, compile the zkey file into the arkzkey format using
+[ark-zkey](https://github.com/seemenkina/ark-zkey).
+This is fork of the [original](https://github.com/zkmopro/ark-zkey) repository with the uncompressed arkzkey support.
 
 ```sh
 # Clone the ark-zkey repository
@@ -252,19 +265,42 @@ cd ark-zkey && cargo build
 cargo run --bin arkzkey-util <path_to_rln_final.zkey>
 ```
 
-Currently, the `rln` module comes with [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) arkzkey keys for the RLN circuit.
+This will generate the `rln_final.arkzkey` file, which is used by the `rln` module.
 
-## Get involved
+Currently, the `rln` module comes with
+[pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources/tree_depth_20) arkzkey keys for the RLN circuit.
 
-Zerokit RLN public and FFI APIs allow interaction with many more features than what briefly showcased above.
+> [!NOTE]
+> You can use this [convert_zkey.sh](./convert_zkey.sh) script
+> to automate the process of generating the arkzkey file from any zkey file
 
-We invite you to check our API documentation by running
+Run the script as follows:
 
-```rust
-cargo doc --no-deps
+```sh
+chmod +x ./convert_zkey.sh
+./convert_zkey.sh <path_to_rln_final.zkey>
 ```
 
-and look at unit tests to have an hint on how to interface and use them.
+## FFI Interface
+
+RLN provides C-compatible bindings for integration with C, C++, Nim, and other languages through [safer_ffi](https://getditto.github.io/safer_ffi/).
+
+The FFI layer is organized into several modules:
+
+- [`ffi_rln.rs`](./src/ffi/ffi_rln.rs) – Implements core RLN functionality, including initialization functions, proof generation, and proof verification.
+- [`ffi_tree.rs`](./src/ffi/ffi_tree.rs) – Provides all tree-related operations and helper functions for Merkle tree management.
+- [`ffi_utils.rs`](./src/ffi/ffi_utils.rs) – Contains all utility functions and structure definitions used across the FFI layer.
+
+### Examples
+
+Working examples demonstrating proof generation, proof verification and slashing in C and Nim:
+
+- [C example](./ffi_c_examples/main.c) and [README](./ffi_c_examples/Readme.md)
+- [Nim example](./ffi_nim_examples/main.nim) and [README](./ffi_nim_examples/Readme.md)
+
+### Memory Management
+
+- All **heap-allocated** objects returned from Rust FFI **must** be freed using their corresponding FFI `_free` functions.
 
 ## Detailed Protocol Flow
 
@@ -276,9 +312,20 @@ and look at unit tests to have an hint on how to interface and use them.
    - Ensures rate-limiting constraints are satisfied
    - Generates a nullifier to prevent double-usage
 5. **Proof Verification**: Verify the proof without revealing the prover's identity
+6. **Slashing Mechanism**: Detect and penalize double-usage attempts
 
 ## Getting Involved
 
+Zerokit RLN public and FFI APIs allow interaction with many more features than what briefly showcased above.
+
+We invite you to check our API documentation by running
+
+```bash
+cargo doc --no-deps
+```
+
+and look at unit tests to have an hint on how to interface and use them.
+
 - Check the [unit tests](https://github.com/vacp2p/zerokit/tree/master/rln/tests) for more usage examples
-- [RFC specification](https://rfc.vac.dev/spec/32/) for the Rate-Limiting Nullifier protocol
+- [RFC specification](https://rfc.vac.dev/vac/raw/rln-v2) for the Rate-Limiting Nullifier protocol
 - [GitHub repository](https://github.com/vacp2p/zerokit) for the latest updates

rln/benches/circuit_loading_arkzkey_benchmark.rs

@@ -1,25 +0,0 @@
-use criterion::{criterion_group, criterion_main, Criterion};
-use rln::circuit::{read_arkzkey_from_bytes_uncompressed, ARKZKEY_BYTES};
-
-pub fn uncompressed_bench(c: &mut Criterion) {
-    let arkzkey = ARKZKEY_BYTES.to_vec();
-    let size = arkzkey.len() as f32;
-    println!(
-        "Size of uncompressed arkzkey: {:.2?} MB",
-        size / 1024.0 / 1024.0
-    );
-
-    c.bench_function("arkzkey::arkzkey_from_raw_uncompressed", |b| {
-        b.iter(|| {
-            let r = read_arkzkey_from_bytes_uncompressed(&arkzkey);
-            assert_eq!(r.is_ok(), true);
-        })
-    });
-}
-
-criterion_group! {
-    name = benches;
-    config = Criterion::default().sample_size(10);
-    targets = uncompressed_bench
-}
-criterion_main!(benches);

rln/benches/circuit_loading_benchmark.rs

@@ -1,24 +0,0 @@
-use criterion::{criterion_group, criterion_main, Criterion};
-use rln::circuit::zkey::read_zkey;
-use std::io::Cursor;
-
-pub fn zkey_load_benchmark(c: &mut Criterion) {
-    let zkey = rln::circuit::ZKEY_BYTES.to_vec();
-    let size = zkey.len() as f32;
-    println!("Size of zkey: {:.2?} MB", size / 1024.0 / 1024.0);
-
-    c.bench_function("zkey::zkey_from_raw", |b| {
-        b.iter(|| {
-            let mut reader = Cursor::new(zkey.clone());
-            let r = read_zkey(&mut reader);
-            assert_eq!(r.is_ok(), true);
-        })
-    });
-}
-
-criterion_group! {
-    name = benches;
-    config = Criterion::default().sample_size(10);
-    targets = zkey_load_benchmark
-}
-criterion_main!(benches);

rln/benches/pmtree_benchmark.rs

@@ -1,11 +1,11 @@
 use criterion::{criterion_group, criterion_main, Criterion};
-use rln::{circuit::Fr, pm_tree_adapter::PmTree};
-use utils::ZerokitMerkleTree;
+use rln::prelude::*;
+use zerokit_utils::merkle_tree::ZerokitMerkleTree;
 
 pub fn pmtree_benchmark(c: &mut Criterion) {
     let mut tree = PmTree::default(2).unwrap();
 
-    let leaves: Vec<Fr> = (0..4).map(|s| Fr::from(s)).collect();
+    let leaves: Vec<Fr> = (0..4).map(Fr::from).collect();
 
     c.bench_function("Pmtree::set", |b| {
         b.iter(|| {
@@ -13,7 +13,7 @@ pub fn pmtree_benchmark(c: &mut Criterion) {
         })
     });
 
-    c.bench_function("Pmtree:delete", |b| {
+    c.bench_function("Pmtree::delete", |b| {
         b.iter(|| {
             tree.delete(0).unwrap();
         })
@@ -26,12 +26,6 @@ pub fn pmtree_benchmark(c: &mut Criterion) {
         })
     });
 
-    c.bench_function("Pmtree::compute_root", |b| {
-        b.iter(|| {
-            tree.compute_root().unwrap();
-        })
-    });
-
     c.bench_function("Pmtree::get", |b| {
         b.iter(|| {
             tree.get(0).unwrap();

rln/benches/poseidon_tree_benchmark.rs

@@ -1,18 +1,15 @@
 use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
-use rln::{
-    circuit::{Fr, TEST_TREE_HEIGHT},
-    hashers::PoseidonHash,
-};
-use utils::{FullMerkleTree, OptimalMerkleTree, ZerokitMerkleTree};
+use rln::prelude::*;
+use zerokit_utils::merkle_tree::{FullMerkleTree, OptimalMerkleTree, ZerokitMerkleTree};
 
 pub fn get_leaves(n: u32) -> Vec<Fr> {
-    (0..n).map(|s| Fr::from(s)).collect()
+    (0..n).map(Fr::from).collect()
 }
 
 pub fn optimal_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
-    c.bench_function("OptimalMerkleTree::<Poseidon>::full_height_gen", |b| {
+    c.bench_function("OptimalMerkleTree::<Poseidon>::full_depth_gen", |b| {
         b.iter(|| {
-            OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+            OptimalMerkleTree::<PoseidonHash>::default(DEFAULT_TREE_DEPTH).unwrap();
         })
     });
 
@@ -20,7 +17,7 @@ pub fn optimal_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
     for &n in [1u32, 10, 100].iter() {
         let leaves = get_leaves(n);
 
-        let mut tree = OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+        let mut tree = OptimalMerkleTree::<PoseidonHash>::default(DEFAULT_TREE_DEPTH).unwrap();
         group.bench_function(
             BenchmarkId::new("OptimalMerkleTree::<Poseidon>::set", n),
             |b| {
@@ -41,9 +38,9 @@ pub fn optimal_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
 }
 
 pub fn full_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
-    c.bench_function("FullMerkleTree::<Poseidon>::full_height_gen", |b| {
+    c.bench_function("FullMerkleTree::<Poseidon>::full_depth_gen", |b| {
         b.iter(|| {
-            FullMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+            FullMerkleTree::<PoseidonHash>::default(DEFAULT_TREE_DEPTH).unwrap();
         })
     });
 
@@ -51,7 +48,7 @@ pub fn full_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
     for &n in [1u32, 10, 100].iter() {
         let leaves = get_leaves(n);
 
-        let mut tree = FullMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+        let mut tree = FullMerkleTree::<PoseidonHash>::default(DEFAULT_TREE_DEPTH).unwrap();
         group.bench_function(
             BenchmarkId::new("FullMerkleTree::<Poseidon>::set", n),
             |b| {

rln/convert_zkey.sh

@@ -0,0 +1,56 @@
+#!/bin/bash
+
+# Convert zkey to arkzkey using /tmp directory
+# Usage: ./convert_zkey.sh <path_to_zkey_file>
+
+set -e
+
+# Check input
+if [ $# -eq 0 ]; then
+    echo "Usage: $0 <path_to_zkey_file>"
+    exit 1
+fi
+
+ZKEY_FILE="$1"
+
+if [ ! -f "$ZKEY_FILE" ]; then
+    echo "Error: File '$ZKEY_FILE' does not exist"
+    exit 1
+fi
+
+# Get absolute path before changing directories
+ZKEY_ABSOLUTE_PATH=$(realpath "$ZKEY_FILE")
+
+# Create temp directory in /tmp
+TEMP_DIR="/tmp/ark-zkey-$$"
+echo "Using temp directory: $TEMP_DIR"
+
+# Cleanup function
+cleanup() {
+    echo "Cleaning up temp directory: $TEMP_DIR"
+    rm -rf "$TEMP_DIR"
+}
+
+# Setup cleanup trap
+trap cleanup EXIT
+
+# Create temp directory and clone ark-zkey
+mkdir -p "$TEMP_DIR"
+cd "$TEMP_DIR"
+git clone https://github.com/seemenkina/ark-zkey.git
+cd ark-zkey
+cargo build
+
+# Convert
+cargo run --bin arkzkey-util "$ZKEY_ABSOLUTE_PATH"
+
+# Check if arkzkey file was created (tool creates it in same directory as input)
+ARKZKEY_FILE="${ZKEY_ABSOLUTE_PATH%.zkey}.arkzkey"
+
+if [ ! -f "$ARKZKEY_FILE" ]; then
+    echo "Could not find generated .arkzkey file at $ARKZKEY_FILE"
+    exit 1
+fi
+
+echo "Conversion successful!"
+echo "Output file: $ARKZKEY_FILE"

rln/ffi_c_examples/Readme.md

@@ -0,0 +1,47 @@
+# RLN FFI C example
+
+This example demonstrates how to use the RLN C FFI in both stateless and non-stateless modes.
+
+## Non-stateless mode
+
+### Compile lib non-stateless
+
+```bash
+cargo build -p rln
+cargo run --features headers --bin generate-headers
+mv -v rln.h rln/ffi_c_examples/
+```
+
+### Compile and run example non-stateless
+
+```bash
+cd rln/ffi_c_examples/
+gcc -Wall main.c -o main -lrln -L../../target/debug
+./main
+```
+
+## Stateless mode
+
+### Compile lib stateless
+
+```bash
+cargo build -p rln --no-default-features --features stateless
+cargo run  --no-default-features --features stateless,headers --bin generate-headers
+mv -v rln.h rln/ffi_c_examples/
+```
+
+### Compile example stateless
+
+```bash
+cd rln/ffi_c_examples/
+gcc -Wall -DSTATELESS main.c -o main -lrln -L../../target/debug
+./main
+```
+
+## Note
+
+### Find C lib used by Rust
+
+```bash
+cargo +nightly rustc --release -p rln -- -Z unstable-options --print native-static-libs
+```

rln/ffi_c_examples/main.c

@@ -0,0 +1,668 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "rln.h"
+
+int main(int argc, char const *const argv[])
+{
+    printf("Creating RLN instance\n");
+
+#ifdef STATELESS
+    CResult_FFI_RLN_ptr_Vec_uint8_t ffi_rln_new_result = ffi_rln_new();
+#else
+    const char *config_path = "../resources/tree_depth_20/config.json";
+    CResult_FFI_RLN_ptr_Vec_uint8_t ffi_rln_new_result = ffi_rln_new(20, config_path);
+#endif
+
+    if (!ffi_rln_new_result.ok)
+    {
+        fprintf(stderr, "Initial RLN instance creation error: %s\n", ffi_rln_new_result.err.ptr);
+        ffi_c_string_free(ffi_rln_new_result.err);
+        return EXIT_FAILURE;
+    }
+
+    FFI_RLN_t *rln = ffi_rln_new_result.ok;
+    printf("RLN instance created successfully\n");
+
+    printf("\nGenerating identity keys\n");
+    CResult_Vec_CFr_Vec_uint8_t keys_result = ffi_key_gen();
+    if (keys_result.err.ptr)
+    {
+        fprintf(stderr, "Key generation error: %s\n", keys_result.err.ptr);
+        ffi_c_string_free(keys_result.err);
+        return EXIT_FAILURE;
+    }
+    Vec_CFr_t keys = keys_result.ok;
+    const CFr_t *identity_secret = ffi_vec_cfr_get(&keys, 0);
+    const CFr_t *id_commitment = ffi_vec_cfr_get(&keys, 1);
+    printf("Identity generated\n");
+
+    Vec_uint8_t debug = ffi_cfr_debug(identity_secret);
+    printf("  - identity_secret = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    debug = ffi_cfr_debug(id_commitment);
+    printf("  - id_commitment = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nCreating message limit\n");
+    CFr_t *user_message_limit = ffi_uint_to_cfr(1);
+
+    debug = ffi_cfr_debug(user_message_limit);
+    printf("  - user_message_limit = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nComputing rate commitment\n");
+    CResult_CFr_ptr_Vec_uint8_t rate_commitment_result = ffi_poseidon_hash_pair(id_commitment, user_message_limit);
+    if (!rate_commitment_result.ok)
+    {
+        fprintf(stderr, "Rate commitment hash error: %s\n", rate_commitment_result.err.ptr);
+        ffi_c_string_free(rate_commitment_result.err);
+        return EXIT_FAILURE;
+    }
+    CFr_t *rate_commitment = rate_commitment_result.ok;
+
+    debug = ffi_cfr_debug(rate_commitment);
+    printf("  - rate_commitment = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nCFr serialization: CFr <-> bytes\n");
+    Vec_uint8_t ser_rate_commitment = ffi_cfr_to_bytes_le(rate_commitment);
+
+    debug = ffi_vec_u8_debug(&ser_rate_commitment);
+    printf("  - serialized rate_commitment = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    CResult_CFr_ptr_Vec_uint8_t deser_rate_commitment_result = ffi_bytes_le_to_cfr(&ser_rate_commitment);
+    if (!deser_rate_commitment_result.ok)
+    {
+        fprintf(stderr, "Rate commitment deserialization error: %s\n", deser_rate_commitment_result.err.ptr);
+        ffi_c_string_free(deser_rate_commitment_result.err);
+        return EXIT_FAILURE;
+    }
+    CFr_t *deser_rate_commitment = deser_rate_commitment_result.ok;
+
+    debug = ffi_cfr_debug(deser_rate_commitment);
+    printf("  - deserialized rate_commitment = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    ffi_vec_u8_free(ser_rate_commitment);
+    ffi_cfr_free(deser_rate_commitment);
+
+    printf("\nVec<CFr> serialization: Vec<CFr> <-> bytes\n");
+    Vec_uint8_t ser_keys = ffi_vec_cfr_to_bytes_le(&keys);
+
+    debug = ffi_vec_u8_debug(&ser_keys);
+    printf("  - serialized keys = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    CResult_Vec_CFr_Vec_uint8_t deser_keys_result = ffi_bytes_le_to_vec_cfr(&ser_keys);
+    if (deser_keys_result.err.ptr)
+    {
+        fprintf(stderr, "Keys deserialization error: %s\n", deser_keys_result.err.ptr);
+        ffi_c_string_free(deser_keys_result.err);
+        return EXIT_FAILURE;
+    }
+
+    debug = ffi_vec_cfr_debug(&deser_keys_result.ok);
+    printf("  - deserialized keys = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    Vec_CFr_t deser_keys = deser_keys_result.ok;
+    ffi_vec_cfr_free(deser_keys);
+
+    ffi_vec_u8_free(ser_keys);
+
+#ifdef STATELESS
+#define TREE_DEPTH 20
+#define CFR_SIZE 32
+
+    printf("\nBuilding Merkle path for stateless mode\n");
+    CFr_t *default_leaf = ffi_cfr_zero();
+
+    CFr_t *default_hashes[TREE_DEPTH - 1];
+    CResult_CFr_ptr_Vec_uint8_t hash_result = ffi_poseidon_hash_pair(default_leaf, default_leaf);
+    if (!hash_result.ok)
+    {
+        fprintf(stderr, "Poseidon hash error: %s\n", hash_result.err.ptr);
+        ffi_c_string_free(hash_result.err);
+        return EXIT_FAILURE;
+    }
+    default_hashes[0] = hash_result.ok;
+    for (size_t i = 1; i < TREE_DEPTH - 1; i++)
+    {
+        hash_result = ffi_poseidon_hash_pair(default_hashes[i - 1], default_hashes[i - 1]);
+        if (!hash_result.ok)
+        {
+            fprintf(stderr, "Poseidon hash error: %s\n", hash_result.err.ptr);
+            ffi_c_string_free(hash_result.err);
+            return EXIT_FAILURE;
+        }
+        default_hashes[i] = hash_result.ok;
+    }
+
+    Vec_CFr_t path_elements = ffi_vec_cfr_new(TREE_DEPTH);
+    ffi_vec_cfr_push(&path_elements, default_leaf);
+    for (size_t i = 0; i < TREE_DEPTH - 1; i++)
+    {
+        ffi_vec_cfr_push(&path_elements, default_hashes[i]);
+    }
+
+    printf("\nVec<CFr> serialization: Vec<CFr> <-> bytes\n");
+    Vec_uint8_t ser_path_elements = ffi_vec_cfr_to_bytes_le(&path_elements);
+
+    debug = ffi_vec_u8_debug(&ser_path_elements);
+    printf("  - serialized path_elements = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    CResult_Vec_CFr_Vec_uint8_t deser_path_elements_result = ffi_bytes_le_to_vec_cfr(&ser_path_elements);
+    if (deser_path_elements_result.err.ptr)
+    {
+        fprintf(stderr, "Path elements deserialization error: %s\n", deser_path_elements_result.err.ptr);
+        ffi_c_string_free(deser_path_elements_result.err);
+        return EXIT_FAILURE;
+    }
+
+    debug = ffi_vec_cfr_debug(&deser_path_elements_result.ok);
+    printf("  - deserialized path_elements = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    Vec_CFr_t deser_path_elements = deser_path_elements_result.ok;
+    ffi_vec_cfr_free(deser_path_elements);
+
+    ffi_vec_u8_free(ser_path_elements);
+
+    uint8_t path_index_arr[TREE_DEPTH] = {0};
+    Vec_uint8_t identity_path_index = {
+        .ptr = path_index_arr,
+        .len = TREE_DEPTH,
+        .cap = TREE_DEPTH};
+
+    printf("\nVec<uint8> serialization: Vec<uint8> <-> bytes\n");
+    Vec_uint8_t ser_path_index = ffi_vec_u8_to_bytes_le(&identity_path_index);
+
+    debug = ffi_vec_u8_debug(&ser_path_index);
+    printf("  - serialized path_index = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    CResult_Vec_uint8_Vec_uint8_t deser_path_index_result = ffi_bytes_le_to_vec_u8(&ser_path_index);
+    if (deser_path_index_result.err.ptr)
+    {
+        fprintf(stderr, "Path index deserialization error: %s\n", deser_path_index_result.err.ptr);
+        ffi_c_string_free(deser_path_index_result.err);
+        return EXIT_FAILURE;
+    }
+
+    debug = ffi_vec_u8_debug(&deser_path_index_result.ok);
+    printf("  - deserialized path_index = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    Vec_uint8_t deser_path_index = deser_path_index_result.ok;
+    ffi_vec_u8_free(deser_path_index);
+
+    ffi_vec_u8_free(ser_path_index);
+
+    printf("\nComputing Merkle root for stateless mode\n");
+    printf("  - computing root for index 0 with rate_commitment\n");
+    CResult_CFr_ptr_Vec_uint8_t root_result = ffi_poseidon_hash_pair(rate_commitment, default_leaf);
+    if (!root_result.ok)
+    {
+        fprintf(stderr, "Poseidon hash error: %s\n", root_result.err.ptr);
+        ffi_c_string_free(root_result.err);
+        return EXIT_FAILURE;
+    }
+    CFr_t *computed_root = root_result.ok;
+    for (size_t i = 1; i < TREE_DEPTH; i++)
+    {
+        root_result = ffi_poseidon_hash_pair(computed_root, default_hashes[i - 1]);
+        if (!root_result.ok)
+        {
+            fprintf(stderr, "Poseidon hash error: %s\n", root_result.err.ptr);
+            ffi_c_string_free(root_result.err);
+            return EXIT_FAILURE;
+        }
+        CFr_t *next_root = root_result.ok;
+        ffi_cfr_free(computed_root);
+        computed_root = next_root;
+    }
+
+    debug = ffi_cfr_debug(computed_root);
+    printf("  - computed_root = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+#else
+    printf("\nAdding rate_commitment to tree\n");
+    CBoolResult_t set_err = ffi_set_next_leaf(&rln, rate_commitment);
+    if (!set_err.ok)
+    {
+        fprintf(stderr, "Set next leaf error: %s\n", set_err.err.ptr);
+        ffi_c_string_free(set_err.err);
+        return EXIT_FAILURE;
+    }
+
+    size_t leaf_index = ffi_leaves_set(&rln) - 1;
+    printf("  - added to tree at index %zu\n", leaf_index);
+
+    printf("\nGetting Merkle proof\n");
+    CResult_FFI_MerkleProof_ptr_Vec_uint8_t proof_result = ffi_get_merkle_proof(&rln, leaf_index);
+    if (!proof_result.ok)
+    {
+        fprintf(stderr, "Get proof error: %s\n", proof_result.err.ptr);
+        ffi_c_string_free(proof_result.err);
+        return EXIT_FAILURE;
+    }
+    FFI_MerkleProof_t *merkle_proof = proof_result.ok;
+    printf("  - proof obtained (depth: %zu)\n", merkle_proof->path_elements.len);
+#endif
+
+    printf("\nHashing signal\n");
+    uint8_t signal[32] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+    Vec_uint8_t signal_vec = {signal, 32, 32};
+    CResult_CFr_ptr_Vec_uint8_t x_result = ffi_hash_to_field_le(&signal_vec);
+    if (!x_result.ok)
+    {
+        fprintf(stderr, "Hash signal error: %s\n", x_result.err.ptr);
+        ffi_c_string_free(x_result.err);
+        return EXIT_FAILURE;
+    }
+    CFr_t *x = x_result.ok;
+
+    debug = ffi_cfr_debug(x);
+    printf("  - x = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nHashing epoch\n");
+    const char *epoch_str = "test-epoch";
+    Vec_uint8_t epoch_vec = {(uint8_t *)epoch_str, strlen(epoch_str), strlen(epoch_str)};
+    CResult_CFr_ptr_Vec_uint8_t epoch_result = ffi_hash_to_field_le(&epoch_vec);
+    if (!epoch_result.ok)
+    {
+        fprintf(stderr, "Hash epoch error: %s\n", epoch_result.err.ptr);
+        ffi_c_string_free(epoch_result.err);
+        return EXIT_FAILURE;
+    }
+    CFr_t *epoch = epoch_result.ok;
+
+    debug = ffi_cfr_debug(epoch);
+    printf("  - epoch = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nHashing RLN identifier\n");
+    const char *rln_id_str = "test-rln-identifier";
+    Vec_uint8_t rln_id_vec = {(uint8_t *)rln_id_str, strlen(rln_id_str), strlen(rln_id_str)};
+    CResult_CFr_ptr_Vec_uint8_t rln_identifier_result = ffi_hash_to_field_le(&rln_id_vec);
+    if (!rln_identifier_result.ok)
+    {
+        fprintf(stderr, "Hash RLN identifier error: %s\n", rln_identifier_result.err.ptr);
+        ffi_c_string_free(rln_identifier_result.err);
+        return EXIT_FAILURE;
+    }
+    CFr_t *rln_identifier = rln_identifier_result.ok;
+
+    debug = ffi_cfr_debug(rln_identifier);
+    printf("  - rln_identifier = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nComputing Poseidon hash for external nullifier\n");
+    CResult_CFr_ptr_Vec_uint8_t external_nullifier_result = ffi_poseidon_hash_pair(epoch, rln_identifier);
+    if (!external_nullifier_result.ok)
+    {
+        fprintf(stderr, "External nullifier hash error: %s\n", external_nullifier_result.err.ptr);
+        ffi_c_string_free(external_nullifier_result.err);
+        return EXIT_FAILURE;
+    }
+    CFr_t *external_nullifier = external_nullifier_result.ok;
+
+    debug = ffi_cfr_debug(external_nullifier);
+    printf("  - external_nullifier = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nCreating message_id\n");
+    CFr_t *message_id = ffi_uint_to_cfr(0);
+
+    debug = ffi_cfr_debug(message_id);
+    printf("  - message_id = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nCreating RLN Witness\n");
+#ifdef STATELESS
+    CResult_FFI_RLNWitnessInput_ptr_Vec_uint8_t witness_result = ffi_rln_witness_input_new(
+        identity_secret,
+        user_message_limit,
+        message_id,
+        &path_elements,
+        &identity_path_index,
+        x,
+        external_nullifier);
+
+    if (!witness_result.ok)
+    {
+        fprintf(stderr, "RLN Witness creation error: %s\n", witness_result.err.ptr);
+        ffi_c_string_free(witness_result.err);
+        return EXIT_FAILURE;
+    }
+    FFI_RLNWitnessInput_t *witness = witness_result.ok;
+    printf("RLN Witness created successfully\n");
+#else
+    CResult_FFI_RLNWitnessInput_ptr_Vec_uint8_t witness_result = ffi_rln_witness_input_new(
+        identity_secret,
+        user_message_limit,
+        message_id,
+        &merkle_proof->path_elements,
+        &merkle_proof->path_index,
+        x,
+        external_nullifier);
+
+    if (!witness_result.ok)
+    {
+        fprintf(stderr, "RLN Witness creation error: %s\n", witness_result.err.ptr);
+        ffi_c_string_free(witness_result.err);
+        return EXIT_FAILURE;
+    }
+    FFI_RLNWitnessInput_t *witness = witness_result.ok;
+    printf("RLN Witness created successfully\n");
+#endif
+
+    printf("\nRLNWitnessInput serialization: RLNWitnessInput <-> bytes\n");
+    CResult_Vec_uint8_Vec_uint8_t ser_witness_result = ffi_rln_witness_to_bytes_le(&witness);
+    if (ser_witness_result.err.ptr)
+    {
+        fprintf(stderr, "Witness serialization error: %s\n", ser_witness_result.err.ptr);
+        ffi_c_string_free(ser_witness_result.err);
+        return EXIT_FAILURE;
+    }
+    Vec_uint8_t ser_witness = ser_witness_result.ok;
+
+    debug = ffi_vec_u8_debug(&ser_witness);
+    printf("  - serialized witness = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    CResult_FFI_RLNWitnessInput_ptr_Vec_uint8_t deser_witness_result = ffi_bytes_le_to_rln_witness(&ser_witness);
+    if (!deser_witness_result.ok)
+    {
+        fprintf(stderr, "Witness deserialization error: %s\n", deser_witness_result.err.ptr);
+        ffi_c_string_free(deser_witness_result.err);
+        return EXIT_FAILURE;
+    }
+
+    FFI_RLNWitnessInput_t *deser_witness = deser_witness_result.ok;
+    printf("  - witness deserialized successfully\n");
+
+    ffi_rln_witness_input_free(deser_witness);
+    ffi_vec_u8_free(ser_witness);
+
+    printf("\nGenerating RLN Proof\n");
+    CResult_FFI_RLNProof_ptr_Vec_uint8_t proof_gen_result = ffi_generate_rln_proof(
+        &rln,
+        &witness);
+
+    if (!proof_gen_result.ok)
+    {
+        fprintf(stderr, "Proof generation error: %s\n", proof_gen_result.err.ptr);
+        ffi_c_string_free(proof_gen_result.err);
+        return EXIT_FAILURE;
+    }
+
+    FFI_RLNProof_t *rln_proof = proof_gen_result.ok;
+    printf("Proof generated successfully\n");
+
+    printf("\nGetting proof values\n");
+    FFI_RLNProofValues_t *proof_values = ffi_rln_proof_get_values(&rln_proof);
+
+    CFr_t *y = ffi_rln_proof_values_get_y(&proof_values);
+    debug = ffi_cfr_debug(y);
+    printf("  - y = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+    ffi_cfr_free(y);
+
+    CFr_t *nullifier = ffi_rln_proof_values_get_nullifier(&proof_values);
+    debug = ffi_cfr_debug(nullifier);
+    printf("  - nullifier = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+    ffi_cfr_free(nullifier);
+
+    CFr_t *root = ffi_rln_proof_values_get_root(&proof_values);
+    debug = ffi_cfr_debug(root);
+    printf("  - root = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+    ffi_cfr_free(root);
+
+    CFr_t *x_val = ffi_rln_proof_values_get_x(&proof_values);
+    debug = ffi_cfr_debug(x_val);
+    printf("  - x = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+    ffi_cfr_free(x_val);
+
+    CFr_t *ext_nullifier = ffi_rln_proof_values_get_external_nullifier(&proof_values);
+    debug = ffi_cfr_debug(ext_nullifier);
+    printf("  - external_nullifier = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+    ffi_cfr_free(ext_nullifier);
+
+    printf("\nRLNProof serialization: RLNProof <-> bytes\n");
+    CResult_Vec_uint8_Vec_uint8_t ser_proof_result = ffi_rln_proof_to_bytes_le(&rln_proof);
+    if (ser_proof_result.err.ptr)
+    {
+        fprintf(stderr, "Proof serialization error: %s\n", ser_proof_result.err.ptr);
+        ffi_c_string_free(ser_proof_result.err);
+        return EXIT_FAILURE;
+    }
+    Vec_uint8_t ser_proof = ser_proof_result.ok;
+
+    debug = ffi_vec_u8_debug(&ser_proof);
+    printf("  - serialized proof = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    CResult_FFI_RLNProof_ptr_Vec_uint8_t deser_proof_result = ffi_bytes_le_to_rln_proof(&ser_proof);
+    if (!deser_proof_result.ok)
+    {
+        fprintf(stderr, "Proof deserialization error: %s\n", deser_proof_result.err.ptr);
+        ffi_c_string_free(deser_proof_result.err);
+        return EXIT_FAILURE;
+    }
+
+    FFI_RLNProof_t *deser_proof = deser_proof_result.ok;
+    printf("  - proof deserialized successfully\n");
+
+    printf("\nRLNProofValues serialization: RLNProofValues <-> bytes\n");
+    Vec_uint8_t ser_proof_values = ffi_rln_proof_values_to_bytes_le(&proof_values);
+
+    debug = ffi_vec_u8_debug(&ser_proof_values);
+    printf("  - serialized proof_values = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    CResult_FFI_RLNProofValues_ptr_Vec_uint8_t deser_proof_values_result = ffi_bytes_le_to_rln_proof_values(&ser_proof_values);
+    if (!deser_proof_values_result.ok)
+    {
+        fprintf(stderr, "Proof values deserialization error: %s\n", deser_proof_values_result.err.ptr);
+        ffi_c_string_free(deser_proof_values_result.err);
+        return EXIT_FAILURE;
+    }
+    FFI_RLNProofValues_t *deser_proof_values = deser_proof_values_result.ok;
+    printf("  - proof_values deserialized successfully\n");
+
+    CFr_t *deser_external_nullifier = ffi_rln_proof_values_get_external_nullifier(&deser_proof_values);
+    debug = ffi_cfr_debug(deser_external_nullifier);
+    printf("  - deserialized external_nullifier = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+    ffi_cfr_free(deser_external_nullifier);
+
+    ffi_rln_proof_values_free(deser_proof_values);
+    ffi_vec_u8_free(ser_proof_values);
+    ffi_rln_proof_free(deser_proof);
+    ffi_vec_u8_free(ser_proof);
+
+    printf("\nVerifying Proof\n");
+#ifdef STATELESS
+    Vec_CFr_t roots = ffi_vec_cfr_from_cfr(computed_root);
+    CBoolResult_t verify_err = ffi_verify_with_roots(&rln, &rln_proof, &roots, x);
+#else
+    CBoolResult_t verify_err = ffi_verify_rln_proof(&rln, &rln_proof, x);
+#endif
+
+    if (!verify_err.ok)
+    {
+        fprintf(stderr, "Proof verification error: %s\n", verify_err.err.ptr);
+        ffi_c_string_free(verify_err.err);
+        return EXIT_FAILURE;
+    }
+
+    printf("Proof verified successfully\n");
+
+    ffi_rln_proof_free(rln_proof);
+
+    printf("\nSimulating double-signaling attack (same epoch, different message)\n");
+
+    printf("\nHashing second signal\n");
+    uint8_t signal2[32] = {11, 12, 13, 14, 15, 16, 17, 18, 19, 20};
+    Vec_uint8_t signal2_vec = {signal2, 32, 32};
+    CResult_CFr_ptr_Vec_uint8_t x2_result = ffi_hash_to_field_le(&signal2_vec);
+    if (!x2_result.ok)
+    {
+        fprintf(stderr, "Hash second signal error: %s\n", x2_result.err.ptr);
+        ffi_c_string_free(x2_result.err);
+        return EXIT_FAILURE;
+    }
+    CFr_t *x2 = x2_result.ok;
+
+    debug = ffi_cfr_debug(x2);
+    printf("  - x2 = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nCreating second message with the same id\n");
+    CFr_t *message_id2 = ffi_uint_to_cfr(0);
+
+    debug = ffi_cfr_debug(message_id2);
+    printf("  - message_id2 = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("\nCreating second RLN Witness\n");
+#ifdef STATELESS
+    CResult_FFI_RLNWitnessInput_ptr_Vec_uint8_t witness_result2 = ffi_rln_witness_input_new(
+        identity_secret,
+        user_message_limit,
+        message_id2,
+        &path_elements,
+        &identity_path_index,
+        x2,
+        external_nullifier);
+
+    if (!witness_result2.ok)
+    {
+        fprintf(stderr, "Second RLN Witness creation error: %s\n", witness_result2.err.ptr);
+        ffi_c_string_free(witness_result2.err);
+        return EXIT_FAILURE;
+    }
+    FFI_RLNWitnessInput_t *witness2 = witness_result2.ok;
+    printf("Second RLN Witness created successfully\n");
+#else
+    CResult_FFI_RLNWitnessInput_ptr_Vec_uint8_t witness_result2 = ffi_rln_witness_input_new(
+        identity_secret,
+        user_message_limit,
+        message_id2,
+        &merkle_proof->path_elements,
+        &merkle_proof->path_index,
+        x2,
+        external_nullifier);
+
+    if (!witness_result2.ok)
+    {
+        fprintf(stderr, "Second RLN Witness creation error: %s\n", witness_result2.err.ptr);
+        ffi_c_string_free(witness_result2.err);
+        return EXIT_FAILURE;
+    }
+    FFI_RLNWitnessInput_t *witness2 = witness_result2.ok;
+    printf("Second RLN Witness created successfully\n");
+#endif
+    printf("\nGenerating second RLN Proof\n");
+    CResult_FFI_RLNProof_ptr_Vec_uint8_t proof_gen_result2 = ffi_generate_rln_proof(
+        &rln,
+        &witness2);
+
+    if (!proof_gen_result2.ok)
+    {
+        fprintf(stderr, "Second proof generation error: %s\n", proof_gen_result2.err.ptr);
+        ffi_c_string_free(proof_gen_result2.err);
+        return EXIT_FAILURE;
+    }
+
+    FFI_RLNProof_t *rln_proof2 = proof_gen_result2.ok;
+    printf("Second proof generated successfully\n");
+
+    FFI_RLNProofValues_t *proof_values2 = ffi_rln_proof_get_values(&rln_proof2);
+
+    printf("\nVerifying second proof\n");
+#ifdef STATELESS
+    CBoolResult_t verify_err2 = ffi_verify_with_roots(&rln, &rln_proof2, &roots, x2);
+#else
+    CBoolResult_t verify_err2 = ffi_verify_rln_proof(&rln, &rln_proof2, x2);
+#endif
+
+    if (!verify_err2.ok)
+    {
+        fprintf(stderr, "Proof verification error: %s\n", verify_err2.err.ptr);
+        ffi_c_string_free(verify_err2.err);
+        return EXIT_FAILURE;
+    }
+
+    printf("Second proof verified successfully\n");
+
+    ffi_rln_proof_free(rln_proof2);
+
+    printf("\nRecovering identity secret\n");
+    CResult_CFr_ptr_Vec_uint8_t recover_result = ffi_recover_id_secret(&proof_values, &proof_values2);
+    if (!recover_result.ok)
+    {
+        fprintf(stderr, "Identity recovery error: %s\n", recover_result.err.ptr);
+        ffi_c_string_free(recover_result.err);
+        return EXIT_FAILURE;
+    }
+
+    CFr_t *recovered_secret = recover_result.ok;
+
+    debug = ffi_cfr_debug(recovered_secret);
+    printf("  - recovered_secret = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    debug = ffi_cfr_debug(identity_secret);
+    printf("  - original_secret  = %s\n", debug.ptr);
+    ffi_c_string_free(debug);
+
+    printf("Slashing successful: Identity is recovered!\n");
+
+    ffi_cfr_free(recovered_secret);
+
+    ffi_rln_proof_values_free(proof_values2);
+    ffi_rln_proof_values_free(proof_values);
+    ffi_cfr_free(x2);
+    ffi_cfr_free(message_id2);
+
+#ifdef STATELESS
+    ffi_rln_witness_input_free(witness2);
+    ffi_rln_witness_input_free(witness);
+    ffi_vec_cfr_free(roots);
+    ffi_vec_cfr_free(path_elements);
+    for (size_t i = 0; i < TREE_DEPTH - 1; i++)
+    {
+        ffi_cfr_free(default_hashes[i]);
+    }
+    ffi_cfr_free(default_leaf);
+    ffi_cfr_free(computed_root);
+#else
+    ffi_rln_witness_input_free(witness2);
+    ffi_rln_witness_input_free(witness);
+    ffi_merkle_proof_free(merkle_proof);
+#endif
+
+    ffi_cfr_free(rate_commitment);
+    ffi_cfr_free(x);
+    ffi_cfr_free(epoch);
+    ffi_cfr_free(rln_identifier);
+    ffi_cfr_free(external_nullifier);
+    ffi_cfr_free(user_message_limit);
+    ffi_cfr_free(message_id);
+    ffi_vec_cfr_free(keys);
+    ffi_rln_free(rln);
+
+    return EXIT_SUCCESS;
+}

rln/ffi_nim_examples/README.md

@@ -0,0 +1,124 @@
+# RLN FFI Nim example
+
+This example demonstrates how to use the RLN C FFI from Nim in both stateless and non-stateless modes. It covers:
+
+- Creating an RLN handle (stateless or with Merkle tree backend)
+- Generating identity keys and commitments
+- Building a witness (mock Merkle path in stateless mode, real Merkle proof in non-stateless mode)
+- Generating and verifying a proof
+- Serializing/deserializing FFI objects (CFr, Vec\<CFr>, RLNWitnessInput, RLNProof, RLNProofValues)
+- Simulating a double-signaling attack and recovering the identity secret
+
+## Build the RLN library
+
+From the repository root:
+
+```bash
+# Stateless build (no tree APIs)
+cargo build -p rln --release --no-default-features --features stateless
+
+# Non-stateless build (with tree APIs)
+cargo build -p rln --release
+```
+
+This produces the shared library in `target/release`:
+
+- macOS: `librln.dylib`
+- Linux: `librln.so`
+- Windows: `rln.dll`
+
+## Build the Nim example (two modes)
+
+From this directory:
+
+```bash
+# Stateless mode (no tree APIs, uses mock Merkle path)
+nim c -d:release -d:ffiStateless main.nim
+
+# Non-stateless mode (uses exported tree APIs to insert leaf and fetch proof)
+nim c -d:release main.nim
+```
+
+Notes:
+
+- The example links dynamically. If your OS linker cannot find the library at runtime,
+  set an rpath or environment variable as shown below.
+- The example auto-picks a platform-specific default library name.
+  You can override it with `-d:RLN_LIB:"/absolute/path/to/lib"` if needed.
+
+## Run the example
+
+Ensure the dynamic loader can find the RLN library, then run the binary.
+
+macOS:
+
+```bash
+DYLD_LIBRARY_PATH=../../target/release ./main
+```
+
+Linux:
+
+```bash
+LD_LIBRARY_PATH=../../target/release ./main
+```
+
+Windows (PowerShell):
+
+```powershell
+$env:PATH = "$PWD\..\..\target\release;$env:PATH"
+./main.exe
+```
+
+You should see detailed output showing each step, for example:
+
+```text
+Creating RLN instance
+RLN instance created successfully
+
+Generating identity keys
+Identity generated
+  - identity_secret = ...
+  - id_commitment = ...
+
+Creating message limit
+  - user_message_limit = ...
+
+Computing rate commitment
+  - rate_commitment = ...
+
+CFr serialization: CFr <-> bytes
+  - serialized rate_commitment = ...
+  - deserialized rate_commitment = ...
+
+Vec<CFr> serialization: Vec<CFr> <-> bytes
+  - serialized keys = ...
+  - deserialized keys = ...
+
+... (Merkle path, hashing, witness, proof, verification, and slashing steps) ...
+
+Proof verified successfully
+Slashing successful: Identity is recovered!
+```
+
+## What the example does
+
+### Stateless mode
+
+1. Creates an RLN handle via the stateless constructor.
+2. Generates identity keys, sets a `user_message_limit` and `message_id`.
+3. Hashes a signal, epoch, and RLN identifier to field elements.
+4. Computes `rateCommitment = Poseidon(id_commitment, user_message_limit)`.
+5. Builds a mock Merkle path for an empty depth-20 tree at index 0 (no exported tree APIs):
+    - Path siblings: level 0 sibling is `0`, then each level uses precomputed default hashes `H(0,0)`, `H(H(0,0),H(0,0))`, ...
+    - Path indices: all zeros (left at every level)
+    - Root: folds the path upwards with `rateCommitment` at index 0
+6. Builds the witness, generates the proof, and verifies it with `ffi_verify_with_roots`, passing a one-element roots vector containing the computed root.
+7. Simulates a double-signaling attack and recovers the identity secret from two proofs.
+
+### Non-stateless mode
+
+1. Creates an RLN handle with a Merkle tree backend and configuration.
+2. Generates identity keys and computes `rateCommitment = Poseidon(id_commitment, user_message_limit)`.
+3. Inserts the leaf with `ffi_set_next_leaf` and fetches a real Merkle path for index 0 via `ffi_get_merkle_proof`.
+4. Builds the witness from the exported proof, generates the proof, and verifies with `ffi_verify_rln_proof` using the current tree root.
+5. Simulates a double-signaling attack and recovers the identity secret from two proofs.

rln/ffi_nim_examples/main.nim

@@ -0,0 +1,940 @@
+# Embed rpaths to find Cargo's built library relative to the executable
+when defined(macosx):
+  {.passL: "-Wl,-rpath,@executable_path/../../target/release".}
+when defined(linux):
+  {.passL: "-Wl,-rpath,'$ORIGIN/../../target/release'".}
+
+# Portable dynlib name with override capability (-d:RLN_LIB:"...")
+when defined(macosx):
+  const RLN_LIB* {.strdefine.} = "librln.dylib"
+elif defined(linux):
+  const RLN_LIB* {.strdefine.} = "librln.so"
+elif defined(windows):
+  const RLN_LIB* {.strdefine.} = "rln.dll"
+else:
+  const RLN_LIB* {.strdefine.} = "rln"
+
+# FFI objects
+type
+  CSize* = csize_t
+  CFr* = object
+  FFI_RLN* = object
+  FFI_RLNProof* = object
+  FFI_RLNWitnessInput* = object
+
+  Vec_CFr* = object
+    dataPtr*: ptr CFr
+    len*: CSize
+    cap*: CSize
+
+  Vec_uint8* = object
+    dataPtr*: ptr uint8
+    len*: CSize
+    cap*: CSize
+
+  SliceRefU8* = object
+    dataPtr*: ptr uint8
+    len*: CSize
+
+  FFI_MerkleProof* = object
+    path_elements*: Vec_CFr
+    path_index*: Vec_uint8
+
+  CResultRLNPtrVecU8* = object
+    ok*: ptr FFI_RLN
+    err*: Vec_uint8
+
+  CResultProofPtrVecU8* = object
+    ok*: ptr FFI_RLNProof
+    err*: Vec_uint8
+
+  CResultWitnessInputPtrVecU8* = object
+    ok*: ptr FFI_RLNWitnessInput
+    err*: Vec_uint8
+
+  FFI_RLNProofValues* = object
+
+  CResultCFrPtrVecU8* = object
+    ok*: ptr CFr
+    err*: Vec_uint8
+
+  CResultRLNProofValuesPtrVecU8* = object
+    ok*: ptr FFI_RLNProofValues
+    err*: Vec_uint8
+
+  CResultMerkleProofPtrVecU8* = object
+    ok*: ptr FFI_MerkleProof
+    err*: Vec_uint8
+
+  CResultVecCFrVecU8* = object
+    ok*: Vec_CFr
+    err*: Vec_uint8
+
+  CResultVecU8VecU8* = object
+    ok*: Vec_uint8
+    err*: Vec_uint8
+
+  CResultBigIntJsonVecU8* = object
+    ok*: Vec_uint8
+    err*: Vec_uint8
+
+  CBoolResult* = object
+    ok*: bool
+    err*: Vec_uint8
+
+# CFr functions
+proc ffi_cfr_zero*(): ptr CFr {.importc: "ffi_cfr_zero", cdecl,
+    dynlib: RLN_LIB.}
+proc ffi_cfr_one*(): ptr CFr {.importc: "ffi_cfr_one", cdecl, dynlib: RLN_LIB.}
+proc ffi_cfr_free*(x: ptr CFr) {.importc: "ffi_cfr_free", cdecl,
+    dynlib: RLN_LIB.}
+proc ffi_uint_to_cfr*(value: uint32): ptr CFr {.importc: "ffi_uint_to_cfr",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_cfr_debug*(cfr: ptr CFr): Vec_uint8 {.importc: "ffi_cfr_debug", cdecl,
+    dynlib: RLN_LIB.}
+proc ffi_cfr_to_bytes_le*(cfr: ptr CFr): Vec_uint8 {.importc: "ffi_cfr_to_bytes_le",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_cfr_to_bytes_be*(cfr: ptr CFr): Vec_uint8 {.importc: "ffi_cfr_to_bytes_be",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_le_to_cfr*(bytes: ptr Vec_uint8): CResultCFrPtrVecU8 {.importc: "ffi_bytes_le_to_cfr",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_be_to_cfr*(bytes: ptr Vec_uint8): CResultCFrPtrVecU8 {.importc: "ffi_bytes_be_to_cfr",
+    cdecl, dynlib: RLN_LIB.}
+
+# Vec<CFr> functions
+proc ffi_vec_cfr_new*(capacity: CSize): Vec_CFr {.importc: "ffi_vec_cfr_new",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_cfr_from_cfr*(cfr: ptr CFr): Vec_CFr {.importc: "ffi_vec_cfr_from_cfr",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_cfr_push*(v: ptr Vec_CFr, cfr: ptr CFr) {.importc: "ffi_vec_cfr_push",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_cfr_len*(v: ptr Vec_CFr): CSize {.importc: "ffi_vec_cfr_len",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_cfr_get*(v: ptr Vec_CFr, i: CSize): ptr CFr {.importc: "ffi_vec_cfr_get",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_cfr_to_bytes_le*(v: ptr Vec_CFr): Vec_uint8 {.importc: "ffi_vec_cfr_to_bytes_le",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_cfr_to_bytes_be*(v: ptr Vec_CFr): Vec_uint8 {.importc: "ffi_vec_cfr_to_bytes_be",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_le_to_vec_cfr*(bytes: ptr Vec_uint8): CResultVecCFrVecU8 {.importc: "ffi_bytes_le_to_vec_cfr",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_be_to_vec_cfr*(bytes: ptr Vec_uint8): CResultVecCFrVecU8 {.importc: "ffi_bytes_be_to_vec_cfr",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_cfr_debug*(v: ptr Vec_CFr): Vec_uint8 {.importc: "ffi_vec_cfr_debug",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_cfr_free*(v: Vec_CFr) {.importc: "ffi_vec_cfr_free", cdecl,
+    dynlib: RLN_LIB.}
+
+# Vec<u8> functions
+proc ffi_vec_u8_to_bytes_le*(v: ptr Vec_uint8): Vec_uint8 {.importc: "ffi_vec_u8_to_bytes_le",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_u8_to_bytes_be*(v: ptr Vec_uint8): Vec_uint8 {.importc: "ffi_vec_u8_to_bytes_be",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_le_to_vec_u8*(bytes: ptr Vec_uint8): CResultVecU8VecU8 {.importc: "ffi_bytes_le_to_vec_u8",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_be_to_vec_u8*(bytes: ptr Vec_uint8): CResultVecU8VecU8 {.importc: "ffi_bytes_be_to_vec_u8",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_u8_debug*(v: ptr Vec_uint8): Vec_uint8 {.importc: "ffi_vec_u8_debug",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_vec_u8_free*(v: Vec_uint8) {.importc: "ffi_vec_u8_free", cdecl,
+    dynlib: RLN_LIB.}
+
+# Hashing functions
+proc ffi_hash_to_field_le*(input: ptr Vec_uint8): CResultCFrPtrVecU8 {.importc: "ffi_hash_to_field_le",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_hash_to_field_be*(input: ptr Vec_uint8): CResultCFrPtrVecU8 {.importc: "ffi_hash_to_field_be",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_poseidon_hash_pair*(a: ptr CFr,
+    b: ptr CFr): CResultCFrPtrVecU8 {.importc: "ffi_poseidon_hash_pair", cdecl,
+    dynlib: RLN_LIB.}
+
+# Keygen function
+proc ffi_key_gen*(): CResultVecCFrVecU8 {.importc: "ffi_key_gen", cdecl,
+    dynlib: RLN_LIB.}
+proc ffi_seeded_key_gen*(seed: ptr Vec_uint8): CResultVecCFrVecU8 {.importc: "ffi_seeded_key_gen",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_extended_key_gen*(): CResultVecCFrVecU8 {.importc: "ffi_extended_key_gen",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_seeded_extended_key_gen*(seed: ptr Vec_uint8): CResultVecCFrVecU8 {.importc: "ffi_seeded_extended_key_gen",
+    cdecl, dynlib: RLN_LIB.}
+
+# RLN instance functions
+when defined(ffiStateless):
+  proc ffi_rln_new*(): CResultRLNPtrVecU8 {.importc: "ffi_rln_new", cdecl,
+      dynlib: RLN_LIB.}
+  proc ffi_rln_new_with_params*(zkey_data: ptr Vec_uint8,
+      graph_data: ptr Vec_uint8): CResultRLNPtrVecU8 {.importc: "ffi_rln_new_with_params",
+      cdecl, dynlib: RLN_LIB.}
+else:
+  proc ffi_rln_new*(treeDepth: CSize, config: cstring): CResultRLNPtrVecU8 {.importc: "ffi_rln_new",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_rln_new_with_params*(treeDepth: CSize, zkey_data: ptr Vec_uint8,
+      graph_data: ptr Vec_uint8, config: cstring): CResultRLNPtrVecU8 {.importc: "ffi_rln_new_with_params",
+      cdecl, dynlib: RLN_LIB.}
+
+proc ffi_rln_free*(rln: ptr FFI_RLN) {.importc: "ffi_rln_free", cdecl,
+    dynlib: RLN_LIB.}
+
+# Witness input functions
+proc ffi_rln_witness_input_new*(
+  identity_secret: ptr CFr,
+  user_message_limit: ptr CFr,
+  message_id: ptr CFr,
+  path_elements: ptr Vec_CFr,
+  identity_path_index: ptr Vec_uint8,
+  x: ptr CFr,
+  external_nullifier: ptr CFr
+): CResultWitnessInputPtrVecU8 {.importc: "ffi_rln_witness_input_new", cdecl,
+    dynlib: RLN_LIB.}
+proc ffi_rln_witness_to_bytes_le*(witness: ptr ptr FFI_RLNWitnessInput): CResultVecU8VecU8 {.importc: "ffi_rln_witness_to_bytes_le",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_witness_to_bytes_be*(witness: ptr ptr FFI_RLNWitnessInput): CResultVecU8VecU8 {.importc: "ffi_rln_witness_to_bytes_be",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_le_to_rln_witness*(bytes: ptr Vec_uint8): CResultWitnessInputPtrVecU8 {.importc: "ffi_bytes_le_to_rln_witness",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_be_to_rln_witness*(bytes: ptr Vec_uint8): CResultWitnessInputPtrVecU8 {.importc: "ffi_bytes_be_to_rln_witness",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_witness_to_bigint_json*(witness: ptr ptr FFI_RLNWitnessInput): CResultBigIntJsonVecU8 {.importc: "ffi_rln_witness_to_bigint_json",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_witness_input_free*(witness: ptr FFI_RLNWitnessInput) {.importc: "ffi_rln_witness_input_free",
+    cdecl, dynlib: RLN_LIB.}
+
+# Proof generation/verification functions
+proc ffi_generate_rln_proof*(
+  rln: ptr ptr FFI_RLN,
+  witness: ptr ptr FFI_RLNWitnessInput
+): CResultProofPtrVecU8 {.importc: "ffi_generate_rln_proof", cdecl,
+    dynlib: RLN_LIB.}
+
+proc ffi_generate_rln_proof_with_witness*(
+  rln: ptr ptr FFI_RLN,
+  calculated_witness: ptr Vec_uint8,
+  witness: ptr ptr FFI_RLNWitnessInput
+): CResultProofPtrVecU8 {.importc: "ffi_generate_rln_proof_with_witness",
+    cdecl, dynlib: RLN_LIB.}
+
+when not defined(ffiStateless):
+  proc ffi_verify_rln_proof*(
+    rln: ptr ptr FFI_RLN,
+    proof: ptr ptr FFI_RLNProof,
+    x: ptr CFr
+  ): CBoolResult {.importc: "ffi_verify_rln_proof", cdecl,
+      dynlib: RLN_LIB.}
+
+proc ffi_verify_with_roots*(
+  rln: ptr ptr FFI_RLN,
+  proof: ptr ptr FFI_RLNProof,
+  roots: ptr Vec_CFr,
+  x: ptr CFr
+): CBoolResult {.importc: "ffi_verify_with_roots", cdecl,
+    dynlib: RLN_LIB.}
+
+proc ffi_rln_proof_free*(p: ptr FFI_RLNProof) {.importc: "ffi_rln_proof_free",
+    cdecl, dynlib: RLN_LIB.}
+
+# Merkle tree operations (non-stateless mode)
+when not defined(ffiStateless):
+  proc ffi_set_tree*(rln: ptr ptr FFI_RLN,
+      tree_depth: CSize): CBoolResult {.importc: "ffi_set_tree",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_delete_leaf*(rln: ptr ptr FFI_RLN,
+      index: CSize): CBoolResult {.importc: "ffi_delete_leaf",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_set_leaf*(rln: ptr ptr FFI_RLN, index: CSize,
+      leaf: ptr CFr): CBoolResult {.importc: "ffi_set_leaf",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_get_leaf*(rln: ptr ptr FFI_RLN,
+      index: CSize): CResultCFrPtrVecU8 {.importc: "ffi_get_leaf",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_set_next_leaf*(rln: ptr ptr FFI_RLN,
+      leaf: ptr CFr): CBoolResult {.importc: "ffi_set_next_leaf",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_set_leaves_from*(rln: ptr ptr FFI_RLN, index: CSize,
+      leaves: ptr Vec_CFr): CBoolResult {.importc: "ffi_set_leaves_from",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_init_tree_with_leaves*(rln: ptr ptr FFI_RLN,
+      leaves: ptr Vec_CFr): CBoolResult {.importc: "ffi_init_tree_with_leaves",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_atomic_operation*(rln: ptr ptr FFI_RLN, index: CSize,
+      leaves: ptr Vec_CFr,
+      indices: ptr Vec_uint8): CBoolResult {.importc: "ffi_atomic_operation",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_seq_atomic_operation*(rln: ptr ptr FFI_RLN, leaves: ptr Vec_CFr,
+      indices: ptr Vec_uint8): CBoolResult {.importc: "ffi_seq_atomic_operation",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_get_root*(rln: ptr ptr FFI_RLN): ptr CFr {.importc: "ffi_get_root",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_leaves_set*(rln: ptr ptr FFI_RLN): CSize {.importc: "ffi_leaves_set",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_get_merkle_proof*(rln: ptr ptr FFI_RLN,
+      index: CSize): CResultMerkleProofPtrVecU8 {.importc: "ffi_get_merkle_proof",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_set_metadata*(rln: ptr ptr FFI_RLN,
+      metadata: ptr Vec_uint8): CBoolResult {.importc: "ffi_set_metadata",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_get_metadata*(rln: ptr ptr FFI_RLN): CResultVecU8VecU8 {.importc: "ffi_get_metadata",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_flush*(rln: ptr ptr FFI_RLN): CBoolResult {.importc: "ffi_flush",
+      cdecl, dynlib: RLN_LIB.}
+  proc ffi_merkle_proof_free*(p: ptr FFI_MerkleProof) {.importc: "ffi_merkle_proof_free",
+      cdecl, dynlib: RLN_LIB.}
+
+# Identity secret recovery
+proc ffi_recover_id_secret*(proof_values_1: ptr ptr FFI_RLNProofValues,
+    proof_values_2: ptr ptr FFI_RLNProofValues): CResultCFrPtrVecU8 {.importc: "ffi_recover_id_secret",
+    cdecl, dynlib: RLN_LIB.}
+
+# RLNProof serialization
+proc ffi_rln_proof_to_bytes_le*(proof: ptr ptr FFI_RLNProof): CResultVecU8VecU8 {.importc: "ffi_rln_proof_to_bytes_le",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_to_bytes_be*(proof: ptr ptr FFI_RLNProof): CResultVecU8VecU8 {.importc: "ffi_rln_proof_to_bytes_be",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_le_to_rln_proof*(bytes: ptr Vec_uint8): CResultProofPtrVecU8 {.importc: "ffi_bytes_le_to_rln_proof",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_be_to_rln_proof*(bytes: ptr Vec_uint8): CResultProofPtrVecU8 {.importc: "ffi_bytes_be_to_rln_proof",
+    cdecl, dynlib: RLN_LIB.}
+
+# RLNProofValues functions
+proc ffi_rln_proof_get_values*(proof: ptr ptr FFI_RLNProof): ptr FFI_RLNProofValues {.importc: "ffi_rln_proof_get_values",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_values_get_y*(pv: ptr ptr FFI_RLNProofValues): ptr CFr {.importc: "ffi_rln_proof_values_get_y",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_values_get_nullifier*(pv: ptr ptr FFI_RLNProofValues): ptr CFr {.importc: "ffi_rln_proof_values_get_nullifier",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_values_get_root*(pv: ptr ptr FFI_RLNProofValues): ptr CFr {.importc: "ffi_rln_proof_values_get_root",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_values_get_x*(pv: ptr ptr FFI_RLNProofValues): ptr CFr {.importc: "ffi_rln_proof_values_get_x",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_values_get_external_nullifier*(pv: ptr ptr FFI_RLNProofValues): ptr CFr {.importc: "ffi_rln_proof_values_get_external_nullifier",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_values_to_bytes_le*(pv: ptr ptr FFI_RLNProofValues): Vec_uint8 {.importc: "ffi_rln_proof_values_to_bytes_le",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_values_to_bytes_be*(pv: ptr ptr FFI_RLNProofValues): Vec_uint8 {.importc: "ffi_rln_proof_values_to_bytes_be",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_le_to_rln_proof_values*(bytes: ptr Vec_uint8): CResultRLNProofValuesPtrVecU8 {.importc: "ffi_bytes_le_to_rln_proof_values",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_bytes_be_to_rln_proof_values*(bytes: ptr Vec_uint8): CResultRLNProofValuesPtrVecU8 {.importc: "ffi_bytes_be_to_rln_proof_values",
+    cdecl, dynlib: RLN_LIB.}
+proc ffi_rln_proof_values_free*(pv: ptr FFI_RLNProofValues) {.importc: "ffi_rln_proof_values_free",
+    cdecl, dynlib: RLN_LIB.}
+
+# Helpers functions
+proc asVecU8*(buf: var seq[uint8]): Vec_uint8 =
+  result.dataPtr = if buf.len == 0: nil else: addr buf[0]
+  result.len = CSize(buf.len)
+  result.cap = CSize(buf.len)
+
+proc asString*(v: Vec_uint8): string =
+  if v.dataPtr.isNil or v.len == 0: return ""
+  result = newString(v.len.int)
+  copyMem(addr result[0], v.dataPtr, v.len.int)
+
+proc ffi_c_string_free*(s: Vec_uint8) {.importc: "ffi_c_string_free", cdecl,
+    dynlib: RLN_LIB.}
+
+when isMainModule:
+  echo "Creating RLN instance"
+
+  var rlnRes: CResultRLNPtrVecU8
+  when defined(ffiStateless):
+    rlnRes = ffi_rln_new()
+  else:
+    let config_path = """../resources/tree_depth_20/config.json""".cstring
+    rlnRes = ffi_rln_new(CSize(20), config_path)
+
+  if rlnRes.ok.isNil:
+    stderr.writeLine "Initial RLN instance creation error: ", asString(rlnRes.err)
+    ffi_c_string_free(rlnRes.err)
+    quit 1
+
+  var rln = rlnRes.ok
+  echo "RLN instance created successfully"
+
+  echo "\nGenerating identity keys"
+  var keysResult = ffi_key_gen()
+  if keysResult.err.dataPtr != nil:
+    let errMsg = asString(keysResult.err)
+    ffi_c_string_free(keysResult.err)
+    echo "Key generation error: ", errMsg
+    quit 1
+  var keys = keysResult.ok
+  let identitySecret = ffi_vec_cfr_get(addr keys, CSize(0))
+  let idCommitment = ffi_vec_cfr_get(addr keys, CSize(1))
+  echo "Identity generated"
+
+  block:
+    let debug = ffi_cfr_debug(identitySecret)
+    echo "  - identity_secret = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  block:
+    let debug = ffi_cfr_debug(idCommitment)
+    echo "  - id_commitment = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nCreating message limit"
+  let userMessageLimit = ffi_uint_to_cfr(1'u32)
+
+  block:
+    let debug = ffi_cfr_debug(userMessageLimit)
+    echo "  - user_message_limit = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nComputing rate commitment"
+  let rateCommitmentResult = ffi_poseidon_hash_pair(idCommitment, userMessageLimit)
+  if rateCommitmentResult.ok.isNil:
+    let errMsg = asString(rateCommitmentResult.err)
+    ffi_c_string_free(rateCommitmentResult.err)
+    echo "Rate commitment hash error: ", errMsg
+    quit 1
+  let rateCommitment = rateCommitmentResult.ok
+
+  block:
+    let debug = ffi_cfr_debug(rateCommitment)
+    echo "  - rate_commitment = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nCFr serialization: CFr <-> bytes"
+  var serRateCommitment = ffi_cfr_to_bytes_be(rateCommitment)
+
+  block:
+    let debug = ffi_vec_u8_debug(addr serRateCommitment)
+    echo "  - serialized rate_commitment = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  let deserRateCommitmentResult = ffi_bytes_be_to_cfr(addr serRateCommitment)
+  if deserRateCommitmentResult.ok.isNil:
+    stderr.writeLine "Rate commitment deserialization error: ", asString(
+        deserRateCommitmentResult.err)
+    ffi_c_string_free(deserRateCommitmentResult.err)
+    quit 1
+  let deserRateCommitment = deserRateCommitmentResult.ok
+
+  block:
+    let debug = ffi_cfr_debug(deserRateCommitment)
+    echo "  - deserialized rate_commitment = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  ffi_vec_u8_free(serRateCommitment)
+  ffi_cfr_free(deserRateCommitment)
+
+  echo "\nVec<CFr> serialization: Vec<CFr> <-> bytes"
+  var serKeys = ffi_vec_cfr_to_bytes_be(addr keys)
+
+  block:
+    let debug = ffi_vec_u8_debug(addr serKeys)
+    echo "  - serialized keys = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  let deserKeysResult = ffi_bytes_be_to_vec_cfr(addr serKeys)
+  if deserKeysResult.err.dataPtr != nil:
+    stderr.writeLine "Keys deserialization error: ", asString(
+        deserKeysResult.err)
+    ffi_c_string_free(deserKeysResult.err)
+    quit 1
+
+  block:
+    var okKeys = deserKeysResult.ok
+    let debug = ffi_vec_cfr_debug(addr okKeys)
+    echo "  - deserialized keys = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  ffi_vec_cfr_free(deserKeysResult.ok)
+  ffi_vec_u8_free(serKeys)
+
+  when defined(ffiStateless):
+    const treeDepth = 20
+    const CFR_SIZE = 32
+
+    echo "\nBuilding Merkle path for stateless mode"
+
+    let defaultLeaf = ffi_cfr_zero()
+    var defaultHashes: array[treeDepth-1, ptr CFr]
+    block:
+      let hashResult = ffi_poseidon_hash_pair(defaultLeaf, defaultLeaf)
+      if hashResult.ok.isNil:
+        let errMsg = asString(hashResult.err)
+        ffi_c_string_free(hashResult.err)
+        echo "Poseidon hash error: ", errMsg
+        quit 1
+      defaultHashes[0] = hashResult.ok
+    for i in 1..treeDepth-2:
+      let hashResult = ffi_poseidon_hash_pair(defaultHashes[i-1], defaultHashes[i-1])
+      if hashResult.ok.isNil:
+        let errMsg = asString(hashResult.err)
+        ffi_c_string_free(hashResult.err)
+        echo "Poseidon hash error: ", errMsg
+        quit 1
+      defaultHashes[i] = hashResult.ok
+
+    var pathElements = ffi_vec_cfr_new(CSize(treeDepth))
+    ffi_vec_cfr_push(addr pathElements, defaultLeaf)
+    for i in 0..treeDepth-2:
+      ffi_vec_cfr_push(addr pathElements, defaultHashes[i])
+
+    echo "\nVec<CFr> serialization: Vec<CFr> <-> bytes"
+    var serPathElements = ffi_vec_cfr_to_bytes_be(addr pathElements)
+
+    block:
+      let debug = ffi_vec_u8_debug(addr serPathElements)
+      echo "  - serialized path_elements = ", asString(debug)
+      ffi_c_string_free(debug)
+
+    let deserPathElements = ffi_bytes_be_to_vec_cfr(addr serPathElements)
+    if deserPathElements.err.dataPtr != nil:
+      stderr.writeLine "Path elements deserialization error: ", asString(
+          deserPathElements.err)
+      ffi_c_string_free(deserPathElements.err)
+      quit 1
+
+    block:
+      var okPathElems = deserPathElements.ok
+      let debug = ffi_vec_cfr_debug(addr okPathElems)
+      echo "  - deserialized path_elements = ", asString(debug)
+      ffi_c_string_free(debug)
+
+    ffi_vec_cfr_free(deserPathElements.ok)
+    ffi_vec_u8_free(serPathElements)
+
+    var pathIndexSeq = newSeq[uint8](treeDepth)
+    var identityPathIndex = asVecU8(pathIndexSeq)
+
+    echo "\nVec<uint8> serialization: Vec<uint8> <-> bytes"
+    var serPathIndex = ffi_vec_u8_to_bytes_be(addr identityPathIndex)
+
+    block:
+      let debug = ffi_vec_u8_debug(addr serPathIndex)
+      echo "  - serialized path_index = ", asString(debug)
+      ffi_c_string_free(debug)
+
+    let deserPathIndex = ffi_bytes_be_to_vec_u8(addr serPathIndex)
+    if deserPathIndex.err.dataPtr != nil:
+      stderr.writeLine "Path index deserialization error: ", asString(
+          deserPathIndex.err)
+      ffi_c_string_free(deserPathIndex.err)
+      quit 1
+
+    block:
+      var okPathIdx = deserPathIndex.ok
+      let debug = ffi_vec_u8_debug(addr okPathIdx)
+      echo "  - deserialized path_index = ", asString(debug)
+      ffi_c_string_free(debug)
+
+    ffi_vec_u8_free(deserPathIndex.ok)
+    ffi_vec_u8_free(serPathIndex)
+
+    echo "\nComputing Merkle root for stateless mode"
+    echo "  - computing root for index 0 with rate_commitment"
+    let rootResult = ffi_poseidon_hash_pair(rateCommitment, defaultLeaf)
+    if rootResult.ok.isNil:
+      let errMsg = asString(rootResult.err)
+      ffi_c_string_free(rootResult.err)
+      echo "Poseidon hash error: ", errMsg
+      quit 1
+    var computedRoot = rootResult.ok
+    for i in 1..treeDepth-1:
+      let nextResult = ffi_poseidon_hash_pair(computedRoot, defaultHashes[i-1])
+      if nextResult.ok.isNil:
+        let errMsg = asString(nextResult.err)
+        ffi_c_string_free(nextResult.err)
+        echo "Poseidon hash error: ", errMsg
+        quit 1
+      let next = nextResult.ok
+      ffi_cfr_free(computedRoot)
+      computedRoot = next
+
+    block:
+      let debug = ffi_cfr_debug(computedRoot)
+      echo "  - computed_root = ", asString(debug)
+      ffi_c_string_free(debug)
+  else:
+    echo "\nAdding rate_commitment to tree"
+    var rcPtr = rateCommitment
+    let setErr = ffi_set_next_leaf(addr rln, rcPtr)
+    if not setErr.ok:
+      stderr.writeLine "Set next leaf error: ", asString(setErr.err)
+      ffi_c_string_free(setErr.err)
+      quit 1
+
+    let leafIndex = ffi_leaves_set(addr rln) - 1
+    echo "  - added to tree at index ", leafIndex
+
+    echo "\nGetting Merkle proof"
+    let proofResult = ffi_get_merkle_proof(addr rln, leafIndex)
+    if proofResult.ok.isNil:
+      stderr.writeLine "Get proof error: ", asString(proofResult.err)
+      ffi_c_string_free(proofResult.err)
+      quit 1
+    let merkleProof = proofResult.ok
+    echo "  - proof obtained (depth: ", merkleProof.path_elements.len, ")"
+
+  echo "\nHashing signal"
+  var signal: array[32, uint8] = [1'u8, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 0, 0, 0,
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+  var signalVec = Vec_uint8(dataPtr: cast[ptr uint8](addr signal[0]),
+      len: CSize(signal.len), cap: CSize(signal.len))
+  let xResult = ffi_hash_to_field_be(addr signalVec)
+  if xResult.ok.isNil:
+    stderr.writeLine "Hash signal error: ", asString(xResult.err)
+    ffi_c_string_free(xResult.err)
+    quit 1
+  let x = xResult.ok
+
+  block:
+    let debug = ffi_cfr_debug(x)
+    echo "  - x = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nHashing epoch"
+  let epochStr = "test-epoch"
+  var epochBytes = newSeq[uint8](epochStr.len)
+  for i in 0..<epochStr.len: epochBytes[i] = uint8(epochStr[i])
+  var epochVec = asVecU8(epochBytes)
+  let epochResult = ffi_hash_to_field_be(addr epochVec)
+  if epochResult.ok.isNil:
+    stderr.writeLine "Hash epoch error: ", asString(epochResult.err)
+    ffi_c_string_free(epochResult.err)
+    quit 1
+  let epoch = epochResult.ok
+
+  block:
+    let debug = ffi_cfr_debug(epoch)
+    echo "  - epoch = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nHashing RLN identifier"
+  let rlnIdStr = "test-rln-identifier"
+  var rlnIdBytes = newSeq[uint8](rlnIdStr.len)
+  for i in 0..<rlnIdStr.len: rlnIdBytes[i] = uint8(rlnIdStr[i])
+  var rlnIdVec = asVecU8(rlnIdBytes)
+  let rlnIdentifierResult = ffi_hash_to_field_be(addr rlnIdVec)
+  if rlnIdentifierResult.ok.isNil:
+    stderr.writeLine "Hash RLN identifier error: ", asString(
+        rlnIdentifierResult.err)
+    ffi_c_string_free(rlnIdentifierResult.err)
+    quit 1
+  let rlnIdentifier = rlnIdentifierResult.ok
+
+  block:
+    let debug = ffi_cfr_debug(rlnIdentifier)
+    echo "  - rln_identifier = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nComputing Poseidon hash for external nullifier"
+  let externalNullifierResult = ffi_poseidon_hash_pair(epoch, rlnIdentifier)
+  if externalNullifierResult.ok.isNil:
+    let errMsg = asString(externalNullifierResult.err)
+    ffi_c_string_free(externalNullifierResult.err)
+    echo "External nullifier hash error: ", errMsg
+    quit 1
+  let externalNullifier = externalNullifierResult.ok
+
+  block:
+    let debug = ffi_cfr_debug(externalNullifier)
+    echo "  - external_nullifier = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nCreating message_id"
+  let messageId = ffi_uint_to_cfr(0'u32)
+
+  block:
+    let debug = ffi_cfr_debug(messageId)
+    echo "  - message_id = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nCreating RLN Witness"
+  when defined(ffiStateless):
+    var witnessRes = ffi_rln_witness_input_new(identitySecret,
+        userMessageLimit, messageId, addr pathElements, addr identityPathIndex,
+        x, externalNullifier)
+    if witnessRes.ok.isNil:
+      stderr.writeLine "RLN Witness creation error: ", asString(witnessRes.err)
+      ffi_c_string_free(witnessRes.err)
+      quit 1
+    var witness = witnessRes.ok
+    echo "RLN Witness created successfully"
+  else:
+    var witnessRes = ffi_rln_witness_input_new(identitySecret,
+        userMessageLimit, messageId, addr merkleProof.path_elements,
+        addr merkleProof.path_index, x, externalNullifier)
+    if witnessRes.ok.isNil:
+      stderr.writeLine "RLN Witness creation error: ", asString(witnessRes.err)
+      ffi_c_string_free(witnessRes.err)
+      quit 1
+    var witness = witnessRes.ok
+    echo "RLN Witness created successfully"
+
+  echo "\nRLNWitnessInput serialization: RLNWitnessInput <-> bytes"
+  let serWitnessResult = ffi_rln_witness_to_bytes_be(addr witness)
+  if serWitnessResult.err.dataPtr != nil:
+    stderr.writeLine "Witness serialization error: ", asString(
+        serWitnessResult.err)
+    ffi_c_string_free(serWitnessResult.err)
+    quit 1
+  var serWitness = serWitnessResult.ok
+
+  block:
+    let debug = ffi_vec_u8_debug(addr serWitness)
+    echo "  - serialized witness = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  let deserWitnessResult = ffi_bytes_be_to_rln_witness(addr serWitness)
+  if deserWitnessResult.ok.isNil:
+    stderr.writeLine "Witness deserialization error: ", asString(
+        deserWitnessResult.err)
+    ffi_c_string_free(deserWitnessResult.err)
+    quit 1
+
+  echo "  - witness deserialized successfully"
+  ffi_rln_witness_input_free(deserWitnessResult.ok)
+  ffi_vec_u8_free(serWitness)
+
+  echo "\nGenerating RLN Proof"
+  var proofRes = ffi_generate_rln_proof(addr rln, addr witness)
+
+  if proofRes.ok.isNil:
+    stderr.writeLine "Proof generation error: ", asString(proofRes.err)
+    ffi_c_string_free(proofRes.err)
+    quit 1
+
+  var proof = proofRes.ok
+  echo "Proof generated successfully"
+
+  echo "\nGetting proof values"
+  var proofValues = ffi_rln_proof_get_values(addr proof)
+
+  block:
+    let y = ffi_rln_proof_values_get_y(addr proofValues)
+    let debug = ffi_cfr_debug(y)
+    echo "  - y = ", asString(debug)
+    ffi_c_string_free(debug)
+    ffi_cfr_free(y)
+
+  block:
+    let nullifier = ffi_rln_proof_values_get_nullifier(addr proofValues)
+    let debug = ffi_cfr_debug(nullifier)
+    echo "  - nullifier = ", asString(debug)
+    ffi_c_string_free(debug)
+    ffi_cfr_free(nullifier)
+
+  block:
+    let root = ffi_rln_proof_values_get_root(addr proofValues)
+    let debug = ffi_cfr_debug(root)
+    echo "  - root = ", asString(debug)
+    ffi_c_string_free(debug)
+    ffi_cfr_free(root)
+
+  block:
+    let xVal = ffi_rln_proof_values_get_x(addr proofValues)
+    let debug = ffi_cfr_debug(xVal)
+    echo "  - x = ", asString(debug)
+    ffi_c_string_free(debug)
+    ffi_cfr_free(xVal)
+
+  block:
+    let extNullifier = ffi_rln_proof_values_get_external_nullifier(
+        addr proofValues)
+    let debug = ffi_cfr_debug(extNullifier)
+    echo "  - external_nullifier = ", asString(debug)
+    ffi_c_string_free(debug)
+    ffi_cfr_free(extNullifier)
+
+  echo "\nRLNProof serialization: RLNProof <-> bytes"
+  let serProofResult = ffi_rln_proof_to_bytes_be(addr proof)
+  if serProofResult.err.dataPtr != nil:
+    stderr.writeLine "Proof serialization error: ", asString(serProofResult.err)
+    ffi_c_string_free(serProofResult.err)
+    quit 1
+  var serProof = serProofResult.ok
+
+  block:
+    let debug = ffi_vec_u8_debug(addr serProof)
+    echo "  - serialized proof = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  let deserProofResult = ffi_bytes_be_to_rln_proof(addr serProof)
+  if deserProofResult.ok.isNil:
+    stderr.writeLine "Proof deserialization error: ", asString(
+        deserProofResult.err)
+    ffi_c_string_free(deserProofResult.err)
+    quit 1
+
+  var deserProof = deserProofResult.ok
+  echo "  - proof deserialized successfully"
+
+  echo "\nRLNProofValues serialization: RLNProofValues <-> bytes"
+  var serProofValues = ffi_rln_proof_values_to_bytes_be(addr proofValues)
+
+  block:
+    let debug = ffi_vec_u8_debug(addr serProofValues)
+    echo "  - serialized proof_values = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  let deserProofValuesResult = ffi_bytes_be_to_rln_proof_values(
+      addr serProofValues)
+  if deserProofValuesResult.ok.isNil:
+    stderr.writeLine "Proof values deserialization error: ", asString(
+        deserProofValuesResult.err)
+    ffi_c_string_free(deserProofValuesResult.err)
+    quit 1
+  var deserProofValues = deserProofValuesResult.ok
+  echo "  - proof_values deserialized successfully"
+
+  block:
+    let deserExternalNullifier = ffi_rln_proof_values_get_external_nullifier(
+        addr deserProofValues)
+    let debug = ffi_cfr_debug(deserExternalNullifier)
+    echo "  - deserialized external_nullifier = ", asString(debug)
+    ffi_c_string_free(debug)
+    ffi_cfr_free(deserExternalNullifier)
+
+  ffi_rln_proof_values_free(deserProofValues)
+  ffi_vec_u8_free(serProofValues)
+  ffi_rln_proof_free(deserProof)
+  ffi_vec_u8_free(serProof)
+
+  echo "\nVerifying Proof"
+  when defined(ffiStateless):
+    var roots = ffi_vec_cfr_from_cfr(computedRoot)
+    let verifyErr = ffi_verify_with_roots(addr rln, addr proof, addr roots, x)
+  else:
+    let verifyErr = ffi_verify_rln_proof(addr rln, addr proof, x)
+
+  if not verifyErr.ok:
+    stderr.writeLine "Proof verification error: ", asString(verifyErr.err)
+    ffi_c_string_free(verifyErr.err)
+    quit 1
+
+  echo "Proof verified successfully"
+
+  ffi_rln_proof_free(proof)
+
+  echo "\nSimulating double-signaling attack (same epoch, different message)"
+
+  echo "\nHashing second signal"
+  var signal2: array[32, uint8] = [11'u8, 12, 13, 14, 15, 16, 17, 18, 19, 20, 0,
+      0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+  var signal2Vec = Vec_uint8(dataPtr: cast[ptr uint8](addr signal2[0]),
+      len: CSize(signal2.len), cap: CSize(signal2.len))
+  let x2Result = ffi_hash_to_field_be(addr signal2Vec)
+  if x2Result.ok.isNil:
+    stderr.writeLine "Hash second signal error: ", asString(x2Result.err)
+    ffi_c_string_free(x2Result.err)
+    quit 1
+  let x2 = x2Result.ok
+
+  block:
+    let debug = ffi_cfr_debug(x2)
+    echo "  - x2 = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nCreating second message with the same id"
+  let messageId2 = ffi_uint_to_cfr(0'u32)
+
+  block:
+    let debug = ffi_cfr_debug(messageId2)
+    echo "  - message_id2 = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "\nCreating second RLN Witness"
+  when defined(ffiStateless):
+    var witnessRes2 = ffi_rln_witness_input_new(identitySecret,
+        userMessageLimit, messageId2, addr pathElements, addr identityPathIndex,
+        x2, externalNullifier)
+    if witnessRes2.ok.isNil:
+      stderr.writeLine "Second RLN Witness creation error: ", asString(
+          witnessRes2.err)
+      ffi_c_string_free(witnessRes2.err)
+      quit 1
+    var witness2 = witnessRes2.ok
+    echo "Second RLN Witness created successfully"
+  else:
+    var witnessRes2 = ffi_rln_witness_input_new(identitySecret,
+        userMessageLimit, messageId2, addr merkleProof.path_elements,
+        addr merkleProof.path_index, x2, externalNullifier)
+    if witnessRes2.ok.isNil:
+      stderr.writeLine "Second RLN Witness creation error: ", asString(
+          witnessRes2.err)
+      ffi_c_string_free(witnessRes2.err)
+      quit 1
+    var witness2 = witnessRes2.ok
+    echo "Second RLN Witness created successfully"
+
+  echo "\nGenerating second RLN Proof"
+  var proofRes2 = ffi_generate_rln_proof(addr rln, addr witness2)
+
+  if proofRes2.ok.isNil:
+    stderr.writeLine "Second proof generation error: ", asString(proofRes2.err)
+    ffi_c_string_free(proofRes2.err)
+    quit 1
+
+  var proof2 = proofRes2.ok
+  echo "Second proof generated successfully"
+
+  var proofValues2 = ffi_rln_proof_get_values(addr proof2)
+
+  echo "\nVerifying second proof"
+  when defined(ffiStateless):
+    let verifyErr2 = ffi_verify_with_roots(addr rln, addr proof2, addr roots, x2)
+  else:
+    let verifyErr2 = ffi_verify_rln_proof(addr rln, addr proof2, x2)
+
+  if not verifyErr2.ok:
+    stderr.writeLine "Proof verification error: ", asString(
+        verifyErr2.err)
+    ffi_c_string_free(verifyErr2.err)
+    quit 1
+
+  echo "Second proof verified successfully"
+
+  echo "\nRecovering identity secret"
+  let recoverRes = ffi_recover_id_secret(addr proofValues, addr proofValues2)
+  if recoverRes.ok.isNil:
+    stderr.writeLine "Identity recovery error: ", asString(recoverRes.err)
+    ffi_c_string_free(recoverRes.err)
+    quit 1
+
+  let recoveredSecret = recoverRes.ok
+
+  block:
+    let debug = ffi_cfr_debug(recoveredSecret)
+    echo "  - recovered_secret = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  block:
+    let debug = ffi_cfr_debug(identitySecret)
+    echo "  - original_secret  = ", asString(debug)
+    ffi_c_string_free(debug)
+
+  echo "Slashing successful: Identity is recovered!"
+  ffi_cfr_free(recoveredSecret)
+
+  ffi_rln_proof_values_free(proofValues2)
+  ffi_rln_proof_values_free(proofValues)
+  ffi_rln_proof_free(proof2)
+  ffi_cfr_free(x2)
+  ffi_cfr_free(messageId2)
+
+  when defined(ffiStateless):
+    ffi_rln_witness_input_free(witness2)
+    ffi_rln_witness_input_free(witness)
+    ffi_vec_cfr_free(roots)
+    ffi_vec_cfr_free(pathElements)
+    for i in 0..treeDepth-2:
+      ffi_cfr_free(defaultHashes[i])
+    ffi_cfr_free(defaultLeaf)
+    ffi_cfr_free(computedRoot)
+  else:
+    ffi_rln_witness_input_free(witness2)
+    ffi_rln_witness_input_free(witness)
+    ffi_merkle_proof_free(merkleProof)
+
+  ffi_cfr_free(rateCommitment)
+  ffi_cfr_free(x)
+  ffi_cfr_free(epoch)
+  ffi_cfr_free(rlnIdentifier)
+  ffi_cfr_free(externalNullifier)
+  ffi_cfr_free(userMessageLimit)
+  ffi_cfr_free(messageId)
+  ffi_vec_cfr_free(keys)
+  ffi_rln_free(rln)

rln/resources/tree_depth_20/config.json

@@ -0,0 +1,9 @@
+{
+  "path": "./database",
+  "temporary": false,
+  "cache_capacity": 1073741824,
+  "flush_every_ms": 500,
+  "mode": "HighThroughput",
+  "use_compression": false,
+  "tree_depth": 20
+}

rln/src/bin/generate-headers.rs

@@ -0,0 +1,5 @@
+use rln::ffi;
+
+fn main() -> std::io::Result<()> {
+    ffi::generate_headers()
+}

rln/src/circuit/error.rs

@@ -0,0 +1,25 @@
+/// Errors that can occur during zkey reading operations
+#[derive(Debug, thiserror::Error)]
+pub enum ZKeyReadError {
+    #[error("Empty zkey bytes provided")]
+    EmptyBytes,
+    #[error("{0}")]
+    SerializationError(#[from] ark_serialize::SerializationError),
+}
+
+/// Errors that can occur during witness calculation
+#[derive(Debug, thiserror::Error)]
+pub enum WitnessCalcError {
+    #[error("Failed to deserialize witness calculation graph: {0}")]
+    GraphDeserialization(#[from] std::io::Error),
+    #[error("Failed to evaluate witness calculation graph: {0}")]
+    GraphEvaluation(String),
+    #[error("Invalid input length for '{name}': expected {expected}, got {actual}")]
+    InvalidInputLength {
+        name: String,
+        expected: usize,
+        actual: usize,
+    },
+    #[error("Missing required input: {0}")]
+    MissingInput(String),
+}

rln/src/circuit/iden3calc.rs

@@ -1,35 +1,66 @@
-// This file is based on the code by iden3. Its preimage can be found here:
+// This crate is based on the code by iden3. Its preimage can be found here:
 // https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/src/lib.rs
 
-pub mod graph;
-pub mod proto;
-pub mod storage;
+mod graph;
+mod proto;
+mod storage;
 
-use ruint::aliases::U256;
 use std::collections::HashMap;
+
+use graph::Node;
+use ruint::aliases::U256;
 use storage::deserialize_witnesscalc_graph;
+use zeroize::zeroize_flat_type;
 
-use crate::circuit::Fr;
-use graph::{fr_to_u256, Node};
+use self::graph::fr_to_u256;
+use super::{error::WitnessCalcError, Fr};
+use crate::utils::FrOrSecret;
 
-pub type InputSignalsInfo = HashMap<String, (usize, usize)>;
+pub(crate) type InputSignalsInfo = HashMap<String, (usize, usize)>;
 
-pub fn calc_witness<I: IntoIterator<Item = (String, Vec<Fr>)>>(
+pub(crate) fn calc_witness<I: IntoIterator<Item = (String, Vec<FrOrSecret>)>>(
     inputs: I,
     graph_data: &[u8],
-) -> Vec<Fr> {
-    let inputs: HashMap<String, Vec<U256>> = inputs
+) -> Result<Vec<Fr>, WitnessCalcError> {
+    let mut inputs: HashMap<String, Vec<U256>> = inputs
         .into_iter()
-        .map(|(key, value)| (key, value.iter().map(fr_to_u256).collect()))
+        .map(|(key, value)| {
+            (
+                key,
+                value
+                    .iter()
+                    .map(|f_| match f_ {
+                        FrOrSecret::IdSecret(s) => s.to_u256(),
+                        FrOrSecret::Fr(f) => fr_to_u256(f),
+                    })
+                    .collect(),
+            )
+        })
         .collect();
 
     let (nodes, signals, input_mapping): (Vec<Node>, Vec<usize>, InputSignalsInfo) =
-        deserialize_witnesscalc_graph(std::io::Cursor::new(graph_data)).unwrap();
+        deserialize_witnesscalc_graph(std::io::Cursor::new(graph_data))?;
 
     let mut inputs_buffer = get_inputs_buffer(get_inputs_size(&nodes));
-    populate_inputs(&inputs, &input_mapping, &mut inputs_buffer);
 
-    graph::evaluate(&nodes, inputs_buffer.as_slice(), &signals)
+    populate_inputs(&inputs, &input_mapping, &mut inputs_buffer)?;
+
+    if let Some(v) = inputs.get_mut("identitySecret") {
+        // DO NOT USE: unsafe { zeroize_flat_type(v) } only clears the Vec pointer, not the data—can cause memory leaks
+
+        for val in v.iter_mut() {
+            unsafe { zeroize_flat_type(val) };
+        }
+    }
+
+    let res = graph::evaluate(&nodes, inputs_buffer.as_slice(), &signals)
+        .map_err(WitnessCalcError::GraphEvaluation)?;
+
+    for val in inputs_buffer.iter_mut() {
+        unsafe { zeroize_flat_type(val) };
+    }
+
+    Ok(res)
 }
 
 fn get_inputs_size(nodes: &[Node]) -> usize {
@@ -52,17 +83,26 @@ fn populate_inputs(
     input_list: &HashMap<String, Vec<U256>>,
     inputs_info: &InputSignalsInfo,
     input_buffer: &mut [U256],
-) {
+) -> Result<(), WitnessCalcError> {
     for (key, value) in input_list {
-        let (offset, len) = inputs_info[key];
-        if len != value.len() {
-            panic!("Invalid input length for {}", key);
+        let (offset, len) = inputs_info
+            .get(key)
+            .ok_or_else(|| WitnessCalcError::MissingInput(key.clone()))?;
+
+        if *len != value.len() {
+            return Err(WitnessCalcError::InvalidInputLength {
+                name: key.clone(),
+                expected: *len,
+                actual: value.len(),
+            });
         }
 
         for (i, v) in value.iter().enumerate() {
             input_buffer[offset + i] = *v;
         }
     }
+
+    Ok(())
 }
 
 /// Allocates inputs vec with position 0 set to 1

rln/src/circuit/iden3calc/graph.rs

@@ -1,22 +1,17 @@
-// This file is based on the code by iden3. Its preimage can be found here:
+// This crate is based on the code by iden3. Its preimage can be found here:
 // https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/src/graph.rs
 
+use std::cmp::Ordering;
+
 use ark_ff::{BigInt, BigInteger, One, PrimeField, Zero};
 use ark_serialize::{CanonicalDeserialize, CanonicalSerialize, Compress, Validate};
-use rand::Rng;
 use ruint::{aliases::U256, uint};
 use serde::{Deserialize, Serialize};
-use std::{
-    cmp::Ordering,
-    collections::HashMap,
-    error::Error,
-    ops::{BitAnd, BitOr, BitXor, Deref, Shl, Shr},
-};
 
-use crate::circuit::iden3calc::proto;
+use super::proto;
 use crate::circuit::Fr;
 
-pub const M: U256 =
+const M: U256 =
     uint!(21888242871839275222246405745257275088548364400416034343698204186575808495617_U256);
 
 fn ark_se<S, A: CanonicalSerialize>(a: &A, s: S) -> Result<S::Ok, S::Error>
@@ -39,17 +34,18 @@ where
 }
 
 #[inline(always)]
-pub fn fr_to_u256(x: &Fr) -> U256 {
+pub(crate) fn fr_to_u256(x: &Fr) -> U256 {
     U256::from_limbs(x.into_bigint().0)
 }
 
 #[inline(always)]
-pub fn u256_to_fr(x: &U256) -> Fr {
-    Fr::from_bigint(BigInt::new(x.into_limbs())).expect("Failed to convert U256 to Fr")
+pub(crate) fn u256_to_fr(x: &U256) -> Result<Fr, String> {
+    Fr::from_bigint(BigInt::new(x.into_limbs()))
+        .ok_or_else(|| "Failed to convert U256 to Fr".to_string())
 }
 
 #[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
-pub enum Operation {
+pub(crate) enum Operation {
     Mul,
     Div,
     Add,
@@ -73,113 +69,76 @@ pub enum Operation {
 }
 
 impl Operation {
-    // TODO: rewrite to &U256 type
-    pub fn eval(&self, a: U256, b: U256) -> U256 {
+    fn eval_fr(&self, a: Fr, b: Fr) -> Result<Fr, String> {
         use Operation::*;
         match self {
-            Mul => a.mul_mod(b, M),
-            Div => {
-                if b == U256::ZERO {
-                    // as we are simulating a circuit execution with signals
-                    // values all equal to 0, just return 0 here in case of
-                    // division by zero
-                    U256::ZERO
-                } else {
-                    a.mul_mod(b.inv_mod(M).unwrap(), M)
-                }
-            }
-            Add => a.add_mod(b, M),
-            Sub => a.add_mod(M - b, M),
-            Pow => a.pow_mod(b, M),
-            Mod => a.div_rem(b).1,
-            Eq => U256::from(a == b),
-            Neq => U256::from(a != b),
-            Lt => u_lt(&a, &b),
-            Gt => u_gt(&a, &b),
-            Leq => u_lte(&a, &b),
-            Geq => u_gte(&a, &b),
-            Land => U256::from(a != U256::ZERO && b != U256::ZERO),
-            Lor => U256::from(a != U256::ZERO || b != U256::ZERO),
-            Shl => compute_shl_uint(a, b),
-            Shr => compute_shr_uint(a, b),
-            // TODO test with conner case when it is possible to get the number
-            //      bigger then modulus
-            Bor => a.bitor(b),
-            Band => a.bitand(b),
-            // TODO test with conner case when it is possible to get the number
-            //      bigger then modulus
-            Bxor => a.bitxor(b),
-            Idiv => a / b,
-        }
-    }
-
-    pub fn eval_fr(&self, a: Fr, b: Fr) -> Fr {
-        use Operation::*;
-        match self {
-            Mul => a * b,
+            Mul => Ok(a * b),
             // We always should return something on the circuit execution.
             // So in case of division by 0 we would return 0. And the proof
             // should be invalid in the end.
             Div => {
                 if b.is_zero() {
-                    Fr::zero()
+                    Ok(Fr::zero())
                 } else {
-                    a / b
+                    Ok(a / b)
                 }
             }
-            Add => a + b,
-            Sub => a - b,
+            Add => Ok(a + b),
+            Sub => Ok(a - b),
+            // Modular exponentiation to prevent overflow and keep result in field
+            Pow => {
+                let a_u256 = fr_to_u256(&a);
+                let b_u256 = fr_to_u256(&b);
+                let result = a_u256.pow_mod(b_u256, M);
+                u256_to_fr(&result)
+            }
+            // Integer division (not field division)
             Idiv => {
                 if b.is_zero() {
-                    Fr::zero()
+                    Ok(Fr::zero())
                 } else {
                     let a_u256 = fr_to_u256(&a);
                     let b_u256 = fr_to_u256(&b);
                     u256_to_fr(&(a_u256 / b_u256))
                 }
             }
+            // Integer modulo (not field arithmetic)
             Mod => {
                 if b.is_zero() {
-                    Fr::zero()
+                    Ok(Fr::zero())
                 } else {
                     let a_u256 = fr_to_u256(&a);
                     let b_u256 = fr_to_u256(&b);
                     u256_to_fr(&(a_u256 % b_u256))
                 }
             }
-            Eq => match a.cmp(&b) {
+            Eq => Ok(match a.cmp(&b) {
                 Ordering::Equal => Fr::one(),
                 _ => Fr::zero(),
-            },
-            Neq => match a.cmp(&b) {
+            }),
+            Neq => Ok(match a.cmp(&b) {
                 Ordering::Equal => Fr::zero(),
                 _ => Fr::one(),
-            },
+            }),
             Lt => u256_to_fr(&u_lt(&fr_to_u256(&a), &fr_to_u256(&b))),
             Gt => u256_to_fr(&u_gt(&fr_to_u256(&a), &fr_to_u256(&b))),
             Leq => u256_to_fr(&u_lte(&fr_to_u256(&a), &fr_to_u256(&b))),
             Geq => u256_to_fr(&u_gte(&fr_to_u256(&a), &fr_to_u256(&b))),
-            Land => {
-                if a.is_zero() || b.is_zero() {
+            Land => Ok(if a.is_zero() || b.is_zero() {
                 Fr::zero()
             } else {
                 Fr::one()
-                }
-            }
-            Lor => {
-                if a.is_zero() && b.is_zero() {
+            }),
+            Lor => Ok(if a.is_zero() && b.is_zero() {
                 Fr::zero()
             } else {
                 Fr::one()
-                }
-            }
+            }),
             Shl => shl(a, b),
             Shr => shr(a, b),
             Bor => bit_or(a, b),
             Band => bit_and(a, b),
             Bxor => bit_xor(a, b),
-            // TODO implement other operators
-            _ => unimplemented!("operator {:?} not implemented for Montgomery", self),
         }
     }
 }
@@ -212,37 +171,27 @@ impl From<&Operation> for proto::DuoOp {
 }
 
 #[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
-pub enum UnoOperation {
+pub(crate) enum UnoOperation {
     Neg,
     Id, // identity - just return self
 }
 
 impl UnoOperation {
-    pub fn eval(&self, a: U256) -> U256 {
-        match self {
-            UnoOperation::Neg => {
-                if a == U256::ZERO {
-                    U256::ZERO
-                } else {
-                    M - a
-                }
-            }
-            UnoOperation::Id => a,
-        }
-    }
-
-    pub fn eval_fr(&self, a: Fr) -> Fr {
+    fn eval_fr(&self, a: Fr) -> Result<Fr, String> {
         match self {
             UnoOperation::Neg => {
                 if a.is_zero() {
-                    Fr::zero()
+                    Ok(Fr::zero())
                 } else {
                     let mut x = Fr::MODULUS;
                     x.sub_with_borrow(&a.into_bigint());
-                    Fr::from_bigint(x).unwrap()
+                    Fr::from_bigint(x).ok_or_else(|| "Failed to compute negation".to_string())
                 }
             }
-            _ => unimplemented!("uno operator {:?} not implemented for Montgomery", self),
+            _ => Err(format!(
+                "uno operator {:?} not implemented for Montgomery",
+                self
+            )),
         }
     }
 }
@@ -257,30 +206,18 @@ impl From<&UnoOperation> for proto::UnoOp {
 }
 
 #[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
-pub enum TresOperation {
+pub(crate) enum TresOperation {
     TernCond,
 }
 
 impl TresOperation {
-    pub fn eval(&self, a: U256, b: U256, c: U256) -> U256 {
-        match self {
-            TresOperation::TernCond => {
-                if a == U256::ZERO {
-                    c
-                } else {
-                    b
-                }
-            }
-        }
-    }
-
-    pub fn eval_fr(&self, a: Fr, b: Fr, c: Fr) -> Fr {
+    fn eval_fr(&self, a: Fr, b: Fr, c: Fr) -> Result<Fr, String> {
         match self {
             TresOperation::TernCond => {
                 if a.is_zero() {
-                    c
+                    Ok(c)
                 } else {
-                    b
+                    Ok(b)
                 }
             }
         }
@@ -296,7 +233,7 @@ impl From<&TresOperation> for proto::TresOp {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
-pub enum Node {
+pub(crate) enum Node {
     Input(usize),
     Constant(U256),
     #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
@@ -306,133 +243,21 @@ pub enum Node {
     TresOp(TresOperation, usize, usize, usize),
 }
 
-// TODO remove pub from Vec<Node>
-#[derive(Default)]
-pub struct Nodes(pub Vec<Node>);
-
-impl Nodes {
-    pub fn new() -> Self {
-        Nodes(Vec::new())
-    }
-
-    pub fn to_const(&self, idx: NodeIdx) -> Result<U256, NodeConstErr> {
-        let me = self.0.get(idx.0).ok_or(NodeConstErr::EmptyNode(idx))?;
-        match me {
-            Node::Constant(v) => Ok(*v),
-            Node::UnoOp(op, a) => Ok(op.eval(self.to_const(NodeIdx(*a))?)),
-            Node::Op(op, a, b) => {
-                Ok(op.eval(self.to_const(NodeIdx(*a))?, self.to_const(NodeIdx(*b))?))
-            }
-            Node::TresOp(op, a, b, c) => Ok(op.eval(
-                self.to_const(NodeIdx(*a))?,
-                self.to_const(NodeIdx(*b))?,
-                self.to_const(NodeIdx(*c))?,
-            )),
-            Node::Input(_) => Err(NodeConstErr::InputSignal),
-            Node::MontConstant(_) => {
-                panic!("MontConstant should not be used here")
-            }
-        }
-    }
-
-    pub fn push(&mut self, n: Node) -> NodeIdx {
-        self.0.push(n);
-        NodeIdx(self.0.len() - 1)
-    }
-
-    pub fn get(&self, idx: NodeIdx) -> Option<&Node> {
-        self.0.get(idx.0)
-    }
-}
-
-impl Deref for Nodes {
-    type Target = Vec<Node>;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-#[derive(Debug, Copy, Clone)]
-pub struct NodeIdx(pub usize);
-
-impl From<usize> for NodeIdx {
-    fn from(v: usize) -> Self {
-        NodeIdx(v)
-    }
-}
-
-#[derive(Debug)]
-pub enum NodeConstErr {
-    EmptyNode(NodeIdx),
-    InputSignal,
-}
-
-impl std::fmt::Display for NodeConstErr {
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            NodeConstErr::EmptyNode(idx) => {
-                write!(f, "empty node at index {}", idx.0)
-            }
-            NodeConstErr::InputSignal => {
-                write!(f, "input signal is not a constant")
-            }
-        }
-    }
-}
-
-impl Error for NodeConstErr {}
-
-fn compute_shl_uint(a: U256, b: U256) -> U256 {
-    debug_assert!(b.lt(&U256::from(256)));
-    let ls_limb = b.as_limbs()[0];
-    a.shl(ls_limb as usize)
-}
-
-fn compute_shr_uint(a: U256, b: U256) -> U256 {
-    debug_assert!(b.lt(&U256::from(256)));
-    let ls_limb = b.as_limbs()[0];
-    a.shr(ls_limb as usize)
-}
-
-/// All references must be backwards.
-fn assert_valid(nodes: &[Node]) {
-    for (i, &node) in nodes.iter().enumerate() {
-        if let Node::Op(_, a, b) = node {
-            assert!(a < i);
-            assert!(b < i);
-        } else if let Node::UnoOp(_, a) = node {
-            assert!(a < i);
-        } else if let Node::TresOp(_, a, b, c) = node {
-            assert!(a < i);
-            assert!(b < i);
-            assert!(c < i);
-        }
-    }
-}
-
-pub fn optimize(nodes: &mut Vec<Node>, outputs: &mut [usize]) {
-    tree_shake(nodes, outputs);
-    propagate(nodes);
-    value_numbering(nodes, outputs);
-    constants(nodes);
-    tree_shake(nodes, outputs);
-    montgomery_form(nodes);
-}
-
-pub fn evaluate(nodes: &[Node], inputs: &[U256], outputs: &[usize]) -> Vec<Fr> {
-    // assert_valid(nodes);
-
+pub(crate) fn evaluate(
+    nodes: &[Node],
+    inputs: &[U256],
+    outputs: &[usize],
+) -> Result<Vec<Fr>, String> {
     // Evaluate the graph.
     let mut values = Vec::with_capacity(nodes.len());
     for &node in nodes.iter() {
         let value = match node {
-            Node::Constant(c) => u256_to_fr(&c),
+            Node::Constant(c) => u256_to_fr(&c)?,
             Node::MontConstant(c) => c,
-            Node::Input(i) => u256_to_fr(&inputs[i]),
-            Node::Op(op, a, b) => op.eval_fr(values[a], values[b]),
-            Node::UnoOp(op, a) => op.eval_fr(values[a]),
-            Node::TresOp(op, a, b, c) => op.eval_fr(values[a], values[b], values[c]),
+            Node::Input(i) => u256_to_fr(&inputs[i])?,
+            Node::Op(op, a, b) => op.eval_fr(values[a], values[b])?,
+            Node::UnoOp(op, a) => op.eval_fr(values[a])?,
+            Node::TresOp(op, a, b, c) => op.eval_fr(values[a], values[b], values[c])?,
         };
         values.push(value);
     }
@@ -443,246 +268,31 @@ pub fn evaluate(nodes: &[Node], inputs: &[U256], outputs: &[usize]) -> Vec<Fr> {
         out[i] = values[outputs[i]];
     }
 
-    out
+    Ok(out)
 }
 
-/// Constant propagation
-pub fn propagate(nodes: &mut [Node]) {
-    assert_valid(nodes);
-    for i in 0..nodes.len() {
-        if let Node::Op(op, a, b) = nodes[i] {
-            if let (Node::Constant(va), Node::Constant(vb)) = (nodes[a], nodes[b]) {
-                nodes[i] = Node::Constant(op.eval(va, vb));
-            } else if a == b {
-                // Not constant but equal
-                use Operation::*;
-                if let Some(c) = match op {
-                    Eq | Leq | Geq => Some(true),
-                    Neq | Lt | Gt => Some(false),
-                    _ => None,
-                } {
-                    nodes[i] = Node::Constant(U256::from(c));
-                }
-            }
-        } else if let Node::UnoOp(op, a) = nodes[i] {
-            if let Node::Constant(va) = nodes[a] {
-                nodes[i] = Node::Constant(op.eval(va));
-            }
-        } else if let Node::TresOp(op, a, b, c) = nodes[i] {
-            if let (Node::Constant(va), Node::Constant(vb), Node::Constant(vc)) =
-                (nodes[a], nodes[b], nodes[c])
-            {
-                nodes[i] = Node::Constant(op.eval(va, vb, vc));
-            }
-        }
-    }
-}
-
-/// Remove unused nodes
-pub fn tree_shake(nodes: &mut Vec<Node>, outputs: &mut [usize]) {
-    assert_valid(nodes);
-
-    // Mark all nodes that are used.
-    let mut used = vec![false; nodes.len()];
-    for &i in outputs.iter() {
-        used[i] = true;
-    }
-
-    // Work backwards from end as all references are backwards.
-    for i in (0..nodes.len()).rev() {
-        if used[i] {
-            if let Node::Op(_, a, b) = nodes[i] {
-                used[a] = true;
-                used[b] = true;
-            }
-            if let Node::UnoOp(_, a) = nodes[i] {
-                used[a] = true;
-            }
-            if let Node::TresOp(_, a, b, c) = nodes[i] {
-                used[a] = true;
-                used[b] = true;
-                used[c] = true;
-            }
-        }
-    }
-
-    // Remove unused nodes
-    let n = nodes.len();
-    let mut retain = used.iter();
-    nodes.retain(|_| *retain.next().unwrap());
-
-    // Renumber references.
-    let mut renumber = vec![None; n];
-    let mut index = 0;
-    for (i, &used) in used.iter().enumerate() {
-        if used {
-            renumber[i] = Some(index);
-            index += 1;
-        }
-    }
-    assert_eq!(index, nodes.len());
-    for (&used, renumber) in used.iter().zip(renumber.iter()) {
-        assert_eq!(used, renumber.is_some());
-    }
-
-    // Renumber references.
-    for node in nodes.iter_mut() {
-        if let Node::Op(_, a, b) = node {
-            *a = renumber[*a].unwrap();
-            *b = renumber[*b].unwrap();
-        }
-        if let Node::UnoOp(_, a) = node {
-            *a = renumber[*a].unwrap();
-        }
-        if let Node::TresOp(_, a, b, c) = node {
-            *a = renumber[*a].unwrap();
-            *b = renumber[*b].unwrap();
-            *c = renumber[*c].unwrap();
-        }
-    }
-    for output in outputs.iter_mut() {
-        *output = renumber[*output].unwrap();
-    }
-}
-
-/// Randomly evaluate the graph
-fn random_eval(nodes: &mut [Node]) -> Vec<U256> {
-    let mut rng = rand::thread_rng();
-    let mut values = Vec::with_capacity(nodes.len());
-    let mut inputs = HashMap::new();
-    let mut prfs = HashMap::new();
-    let mut prfs_uno = HashMap::new();
-    let mut prfs_tres = HashMap::new();
-    for node in nodes.iter() {
-        use Operation::*;
-        let value = match node {
-            // Constants evaluate to themselves
-            Node::Constant(c) => *c,
-
-            Node::MontConstant(_) => unimplemented!("should not be used"),
-
-            // Algebraic Ops are evaluated directly
-            // Since the field is large, by Swartz-Zippel if
-            // two values are the same then they are likely algebraically equal.
-            Node::Op(op @ (Add | Sub | Mul), a, b) => op.eval(values[*a], values[*b]),
-
-            // Input and non-algebraic ops are random functions
-            // TODO: https://github.com/recmo/uint/issues/95 and use .gen_range(..M)
-            Node::Input(i) => *inputs.entry(*i).or_insert_with(|| rng.gen::<U256>() % M),
-            Node::Op(op, a, b) => *prfs
-                .entry((*op, values[*a], values[*b]))
-                .or_insert_with(|| rng.gen::<U256>() % M),
-            Node::UnoOp(op, a) => *prfs_uno
-                .entry((*op, values[*a]))
-                .or_insert_with(|| rng.gen::<U256>() % M),
-            Node::TresOp(op, a, b, c) => *prfs_tres
-                .entry((*op, values[*a], values[*b], values[*c]))
-                .or_insert_with(|| rng.gen::<U256>() % M),
-        };
-        values.push(value);
-    }
-    values
-}
-
-/// Value numbering
-pub fn value_numbering(nodes: &mut [Node], outputs: &mut [usize]) {
-    assert_valid(nodes);
-
-    // Evaluate the graph in random field elements.
-    let values = random_eval(nodes);
-
-    // Find all nodes with the same value.
-    let mut value_map = HashMap::new();
-    for (i, &value) in values.iter().enumerate() {
-        value_map.entry(value).or_insert_with(Vec::new).push(i);
-    }
-
-    // For nodes that are the same, pick the first index.
-    let renumber: Vec<_> = values.into_iter().map(|v| value_map[&v][0]).collect();
-
-    // Renumber references.
-    for node in nodes.iter_mut() {
-        if let Node::Op(_, a, b) = node {
-            *a = renumber[*a];
-            *b = renumber[*b];
-        }
-        if let Node::UnoOp(_, a) = node {
-            *a = renumber[*a];
-        }
-        if let Node::TresOp(_, a, b, c) = node {
-            *a = renumber[*a];
-            *b = renumber[*b];
-            *c = renumber[*c];
-        }
-    }
-    for output in outputs.iter_mut() {
-        *output = renumber[*output];
-    }
-}
-
-/// Probabilistic constant determination
-pub fn constants(nodes: &mut [Node]) {
-    assert_valid(nodes);
-
-    // Evaluate the graph in random field elements.
-    let values_a = random_eval(nodes);
-    let values_b = random_eval(nodes);
-
-    // Find all nodes with the same value.
-    for i in 0..nodes.len() {
-        if let Node::Constant(_) = nodes[i] {
-            continue;
-        }
-        if values_a[i] == values_b[i] {
-            nodes[i] = Node::Constant(values_a[i]);
-        }
-    }
-}
-
-/// Convert to Montgomery form
-pub fn montgomery_form(nodes: &mut [Node]) {
-    for node in nodes.iter_mut() {
-        use Node::*;
-        use Operation::*;
-        match node {
-            Constant(c) => *node = MontConstant(u256_to_fr(c)),
-            MontConstant(..) => (),
-            Input(..) => (),
-            Op(
-                Mul | Div | Add | Sub | Idiv | Mod | Eq | Neq | Lt | Gt | Leq | Geq | Land | Lor
-                | Shl | Shr | Bor | Band | Bxor,
-                ..,
-            ) => (),
-            Op(op @ Pow, ..) => unimplemented!("Operators Montgomery form: {:?}", op),
-            UnoOp(UnoOperation::Neg, ..) => (),
-            UnoOp(op, ..) => unimplemented!("Uno Operators Montgomery form: {:?}", op),
-            TresOp(TresOperation::TernCond, ..) => (),
-        }
-    }
-}
-
-fn shl(a: Fr, b: Fr) -> Fr {
+fn shl(a: Fr, b: Fr) -> Result<Fr, String> {
     if b.is_zero() {
-        return a;
+        return Ok(a);
     }
 
     if b.cmp(&Fr::from(Fr::MODULUS_BIT_SIZE)).is_ge() {
-        return Fr::zero();
+        return Ok(Fr::zero());
     }
 
     let n = b.into_bigint().0[0] as u32;
     let a = a.into_bigint();
-    Fr::from_bigint(a << n).unwrap()
+    Fr::from_bigint(a << n).ok_or_else(|| "Failed to compute left shift".to_string())
 }
 
-fn shr(a: Fr, b: Fr) -> Fr {
+fn shr(a: Fr, b: Fr) -> Result<Fr, String> {
     if b.is_zero() {
-        return a;
+        return Ok(a);
     }
 
     match b.cmp(&Fr::from(254u64)) {
-        Ordering::Equal => return Fr::zero(),
-        Ordering::Greater => return Fr::zero(),
+        Ordering::Equal => return Ok(Fr::zero()),
+        Ordering::Greater => return Ok(Fr::zero()),
         _ => (),
     };
 
@@ -698,7 +308,7 @@ fn shr(a: Fr, b: Fr) -> Fr {
     }
 
     if n == 0 {
-        return Fr::from_bigint(result).unwrap();
+        return Fr::from_bigint(result).ok_or_else(|| "Failed to compute right shift".to_string());
     }
 
     let mask: u64 = (1 << n) - 1;
@@ -709,10 +319,10 @@ fn shr(a: Fr, b: Fr) -> Fr {
         c[i] = (c[i] >> n) | (carrier << (64 - n));
         carrier = new_carrier;
     }
-    Fr::from_bigint(result).unwrap()
+    Fr::from_bigint(result).ok_or_else(|| "Failed to compute right shift".to_string())
 }
 
-fn bit_and(a: Fr, b: Fr) -> Fr {
+fn bit_and(a: Fr, b: Fr) -> Result<Fr, String> {
     let a = a.into_bigint();
     let b = b.into_bigint();
     let c: [u64; 4] = [
@@ -726,10 +336,10 @@ fn bit_and(a: Fr, b: Fr) -> Fr {
         d.sub_with_borrow(&Fr::MODULUS);
     }
 
-    Fr::from_bigint(d).unwrap()
+    Fr::from_bigint(d).ok_or_else(|| "Failed to compute bitwise AND".to_string())
 }
 
-fn bit_or(a: Fr, b: Fr) -> Fr {
+fn bit_or(a: Fr, b: Fr) -> Result<Fr, String> {
     let a = a.into_bigint();
     let b = b.into_bigint();
     let c: [u64; 4] = [
@@ -743,10 +353,10 @@ fn bit_or(a: Fr, b: Fr) -> Fr {
         d.sub_with_borrow(&Fr::MODULUS);
     }
 
-    Fr::from_bigint(d).unwrap()
+    Fr::from_bigint(d).ok_or_else(|| "Failed to compute bitwise OR".to_string())
 }
 
-fn bit_xor(a: Fr, b: Fr) -> Fr {
+fn bit_xor(a: Fr, b: Fr) -> Result<Fr, String> {
     let a = a.into_bigint();
     let b = b.into_bigint();
     let c: [u64; 4] = [
@@ -760,7 +370,7 @@ fn bit_xor(a: Fr, b: Fr) -> Fr {
         d.sub_with_borrow(&Fr::MODULUS);
     }
 
-    Fr::from_bigint(d).unwrap()
+    Fr::from_bigint(d).ok_or_else(|| "Failed to compute bitwise XOR".to_string())
 }
 
 // M / 2
@@ -816,24 +426,27 @@ fn u_lt(a: &U256, b: &U256) -> U256 {
 }
 
 #[cfg(test)]
-mod tests {
-    use super::*;
+mod test {
+    use std::{ops::Div, str::FromStr};
+
     use ruint::uint;
-    use std::ops::Div;
-    use std::str::FromStr;
+
+    use super::*;
 
     #[test]
     fn test_ok() {
         let a = Fr::from(4u64);
         let b = Fr::from(2u64);
-        let c = shl(a, b);
+        let c = shl(a, b).unwrap();
         assert_eq!(c.cmp(&Fr::from(16u64)), Ordering::Equal)
     }
 
     #[test]
     fn test_div() {
         assert_eq!(
-            Operation::Div.eval_fr(Fr::from(2u64), Fr::from(3u64)),
+            Operation::Div
+                .eval_fr(Fr::from(2u64), Fr::from(3u64))
+                .unwrap(),
             Fr::from_str(
                 "7296080957279758407415468581752425029516121466805344781232734728858602831873"
             )
@@ -841,12 +454,16 @@ mod tests {
         );
 
         assert_eq!(
-            Operation::Div.eval_fr(Fr::from(6u64), Fr::from(2u64)),
+            Operation::Div
+                .eval_fr(Fr::from(6u64), Fr::from(2u64))
+                .unwrap(),
             Fr::from_str("3").unwrap()
         );
 
         assert_eq!(
-            Operation::Div.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Operation::Div
+                .eval_fr(Fr::from(7u64), Fr::from(2u64))
+                .unwrap(),
             Fr::from_str(
                 "10944121435919637611123202872628637544274182200208017171849102093287904247812"
             )
@@ -857,17 +474,23 @@ mod tests {
     #[test]
     fn test_idiv() {
         assert_eq!(
-            Operation::Idiv.eval_fr(Fr::from(2u64), Fr::from(3u64)),
+            Operation::Idiv
+                .eval_fr(Fr::from(2u64), Fr::from(3u64))
+                .unwrap(),
             Fr::from_str("0").unwrap()
         );
 
         assert_eq!(
-            Operation::Idiv.eval_fr(Fr::from(6u64), Fr::from(2u64)),
+            Operation::Idiv
+                .eval_fr(Fr::from(6u64), Fr::from(2u64))
+                .unwrap(),
             Fr::from_str("3").unwrap()
         );
 
         assert_eq!(
-            Operation::Idiv.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Operation::Idiv
+                .eval_fr(Fr::from(7u64), Fr::from(2u64))
+                .unwrap(),
             Fr::from_str("3").unwrap()
         );
     }
@@ -875,12 +498,16 @@ mod tests {
     #[test]
     fn test_fr_mod() {
         assert_eq!(
-            Operation::Mod.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Operation::Mod
+                .eval_fr(Fr::from(7u64), Fr::from(2u64))
+                .unwrap(),
             Fr::from_str("1").unwrap()
         );
 
         assert_eq!(
-            Operation::Mod.eval_fr(Fr::from(7u64), Fr::from(9u64)),
+            Operation::Mod
+                .eval_fr(Fr::from(7u64), Fr::from(9u64))
+                .unwrap(),
             Fr::from_str("7").unwrap()
         );
     }
@@ -944,14 +571,14 @@ mod tests {
         let x = M.div(uint!(2_U256));
 
         println!("x: {:?}", x.as_limbs());
-        println!("x: {}", M);
+        println!("x: {M}");
     }
 
     #[test]
     fn test_2() {
         let nodes: Vec<Node> = vec![];
         // let node = nodes[0];
-        let node = nodes.get(0);
-        println!("{:?}", node);
+        let node = nodes.first();
+        println!("{node:?}");
     }
 }

rln/src/circuit/iden3calc/proto.rs

@@ -1,33 +1,33 @@
-// This file has been generated by prost-build during compilation of the code by iden3
+// This crate has been generated by prost-build during compilation of the code by iden3
 // and modified manually. The *.proto file used to generate this on can be found here:
 // https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/protos/messages.proto
 
 use std::collections::HashMap;
 
-#[derive(Clone, PartialEq, ::prost::Message)]
-pub struct BigUInt {
+#[derive(Clone, PartialEq, prost::Message)]
+pub(crate) struct BigUInt {
     #[prost(bytes = "vec", tag = "1")]
     pub value_le: Vec<u8>,
 }
-#[derive(Clone, Copy, PartialEq, ::prost::Message)]
-pub struct InputNode {
+#[derive(Clone, Copy, PartialEq, prost::Message)]
+pub(crate) struct InputNode {
     #[prost(uint32, tag = "1")]
     pub idx: u32,
 }
-#[derive(Clone, PartialEq, ::prost::Message)]
-pub struct ConstantNode {
+#[derive(Clone, PartialEq, prost::Message)]
+pub(crate) struct ConstantNode {
     #[prost(message, optional, tag = "1")]
     pub value: Option<BigUInt>,
 }
-#[derive(Clone, Copy, PartialEq, ::prost::Message)]
-pub struct UnoOpNode {
+#[derive(Clone, Copy, PartialEq, prost::Message)]
+pub(crate) struct UnoOpNode {
     #[prost(enumeration = "UnoOp", tag = "1")]
     pub op: i32,
     #[prost(uint32, tag = "2")]
     pub a_idx: u32,
 }
-#[derive(Clone, Copy, PartialEq, ::prost::Message)]
-pub struct DuoOpNode {
+#[derive(Clone, Copy, PartialEq, prost::Message)]
+pub(crate) struct DuoOpNode {
     #[prost(enumeration = "DuoOp", tag = "1")]
     pub op: i32,
     #[prost(uint32, tag = "2")]
@@ -35,8 +35,8 @@ pub struct DuoOpNode {
     #[prost(uint32, tag = "3")]
     pub b_idx: u32,
 }
-#[derive(Clone, Copy, PartialEq, ::prost::Message)]
-pub struct TresOpNode {
+#[derive(Clone, Copy, PartialEq, prost::Message)]
+pub(crate) struct TresOpNode {
     #[prost(enumeration = "TresOp", tag = "1")]
     pub op: i32,
     #[prost(uint32, tag = "2")]
@@ -46,15 +46,15 @@ pub struct TresOpNode {
     #[prost(uint32, tag = "4")]
     pub c_idx: u32,
 }
-#[derive(Clone, PartialEq, ::prost::Message)]
-pub struct Node {
+#[derive(Clone, PartialEq, prost::Message)]
+pub(crate) struct Node {
     #[prost(oneof = "node::Node", tags = "1, 2, 3, 4, 5")]
     pub node: Option<node::Node>,
 }
 /// Nested message and enum types in `Node`.
-pub mod node {
-    #[derive(Clone, PartialEq, ::prost::Oneof)]
-    pub enum Node {
+pub(crate) mod node {
+    #[derive(Clone, PartialEq, prost::Oneof)]
+    pub(crate) enum Node {
         #[prost(message, tag = "1")]
         Input(super::InputNode),
         #[prost(message, tag = "2")]
@@ -67,22 +67,22 @@ pub mod node {
         TresOp(super::TresOpNode),
     }
 }
-#[derive(Clone, Copy, PartialEq, ::prost::Message)]
-pub struct SignalDescription {
+#[derive(Clone, Copy, PartialEq, prost::Message)]
+pub(crate) struct SignalDescription {
     #[prost(uint32, tag = "1")]
     pub offset: u32,
     #[prost(uint32, tag = "2")]
     pub len: u32,
 }
-#[derive(Clone, PartialEq, ::prost::Message)]
-pub struct GraphMetadata {
+#[derive(Clone, PartialEq, prost::Message)]
+pub(crate) struct GraphMetadata {
     #[prost(uint32, repeated, tag = "1")]
     pub witness_signals: Vec<u32>,
     #[prost(map = "string, message", tag = "2")]
     pub inputs: HashMap<String, SignalDescription>,
 }
-#[derive(Clone, Copy, Debug, PartialEq, ::prost::Enumeration)]
-pub enum DuoOp {
+#[derive(Clone, Copy, Debug, PartialEq, prost::Enumeration)]
+pub(crate) enum DuoOp {
     Mul = 0,
     Div = 1,
     Add = 2,
@@ -105,13 +105,13 @@ pub enum DuoOp {
     Bxor = 19,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, ::prost::Enumeration)]
-pub enum UnoOp {
+#[derive(Clone, Copy, Debug, PartialEq, prost::Enumeration)]
+pub(crate) enum UnoOp {
     Neg = 0,
     Id = 1,
 }
 
-#[derive(Clone, Copy, Debug, PartialEq, ::prost::Enumeration)]
-pub enum TresOp {
+#[derive(Clone, Copy, Debug, PartialEq, prost::Enumeration)]
+pub(crate) enum TresOp {
     TernCond = 0,
 }

rln/src/circuit/iden3calc/storage.rs

@@ -1,57 +1,86 @@
-// This file is based on the code by iden3. Its preimage can be found here:
+// This crate is based on the code by iden3. Its preimage can be found here:
 // https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/src/storage.rs
 
-use ark_bn254::Fr;
+use std::io::{Read, Write};
+
 use ark_ff::PrimeField;
 use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
 use prost::Message;
-use std::io::{Read, Write};
 
-use crate::circuit::iden3calc::{
-    graph,
-    graph::{Operation, TresOperation, UnoOperation},
+use super::{
+    graph::{self, Operation, TresOperation, UnoOperation},
     proto, InputSignalsInfo,
 };
+use crate::circuit::Fr;
 
-// format of the wtns.graph file:
-// + magic line: wtns.graph.001
-// + 4 bytes unsigned LE 32-bit integer: number of nodes
-// + series of protobuf serialized nodes. Each node prefixed by varint length
-// + protobuf serialized GraphMetadata
-// + 8 bytes unsigned LE 64-bit integer: offset of GraphMetadata message
-
+/// Format of the wtns.graph file:
+/// + magic line: wtns.graph.001
+/// + 4 bytes unsigned LE 32-bit integer: number of nodes
+/// + series of protobuf serialized nodes. Each node prefixed by varint length
+/// + protobuf serialized GraphMetadata
+/// + 8 bytes unsigned LE 64-bit integer: offset of GraphMetadata message
 const WITNESSCALC_GRAPH_MAGIC: &[u8] = b"wtns.graph.001";
 
 const MAX_VARINT_LENGTH: usize = 10;
 
-impl From<proto::Node> for graph::Node {
-    fn from(value: proto::Node) -> Self {
-        match value.node.unwrap() {
-            proto::node::Node::Input(input_node) => graph::Node::Input(input_node.idx as usize),
+impl TryFrom<proto::Node> for graph::Node {
+    type Error = std::io::Error;
+
+    fn try_from(value: proto::Node) -> Result<Self, Self::Error> {
+        let node = value.node.ok_or_else(|| {
+            std::io::Error::new(
+                std::io::ErrorKind::InvalidData,
+                "Proto::Node must have a node field",
+            )
+        })?;
+        match node {
+            proto::node::Node::Input(input_node) => Ok(graph::Node::Input(input_node.idx as usize)),
             proto::node::Node::Constant(constant_node) => {
-                let i = constant_node.value.unwrap();
-                graph::Node::MontConstant(Fr::from_le_bytes_mod_order(i.value_le.as_slice()))
+                let i = constant_node.value.ok_or_else(|| {
+                    std::io::Error::new(
+                        std::io::ErrorKind::InvalidData,
+                        "Constant node must have a value",
+                    )
+                })?;
+                Ok(graph::Node::MontConstant(Fr::from_le_bytes_mod_order(
+                    i.value_le.as_slice(),
+                )))
             }
             proto::node::Node::UnoOp(uno_op_node) => {
-                let op = proto::UnoOp::try_from(uno_op_node.op).unwrap();
-                graph::Node::UnoOp(op.into(), uno_op_node.a_idx as usize)
+                let op = proto::UnoOp::try_from(uno_op_node.op).map_err(|_| {
+                    std::io::Error::new(
+                        std::io::ErrorKind::InvalidData,
+                        "UnoOp must be valid enum value",
+                    )
+                })?;
+                Ok(graph::Node::UnoOp(op.into(), uno_op_node.a_idx as usize))
             }
             proto::node::Node::DuoOp(duo_op_node) => {
-                let op = proto::DuoOp::try_from(duo_op_node.op).unwrap();
-                graph::Node::Op(
+                let op = proto::DuoOp::try_from(duo_op_node.op).map_err(|_| {
+                    std::io::Error::new(
+                        std::io::ErrorKind::InvalidData,
+                        "DuoOp must be valid enum value",
+                    )
+                })?;
+                Ok(graph::Node::Op(
                     op.into(),
                     duo_op_node.a_idx as usize,
                     duo_op_node.b_idx as usize,
-                )
+                ))
             }
             proto::node::Node::TresOp(tres_op_node) => {
-                let op = proto::TresOp::try_from(tres_op_node.op).unwrap();
-                graph::Node::TresOp(
+                let op = proto::TresOp::try_from(tres_op_node.op).map_err(|_| {
+                    std::io::Error::new(
+                        std::io::ErrorKind::InvalidData,
+                        "TresOp must be valid enum value",
+                    )
+                })?;
+                Ok(graph::Node::TresOp(
                     op.into(),
                     tres_op_node.a_idx as usize,
                     tres_op_node.b_idx as usize,
                     tres_op_node.c_idx as usize,
-                )
+                ))
             }
         }
     }
@@ -137,14 +166,15 @@ impl From<proto::TresOp> for graph::TresOperation {
     }
 }
 
-pub fn serialize_witnesscalc_graph<T: Write>(
+#[allow(dead_code)]
+pub(crate) fn serialize_witnesscalc_graph<T: Write>(
     mut w: T,
     nodes: &Vec<graph::Node>,
     witness_signals: &[usize],
     input_signals: &InputSignalsInfo,
 ) -> std::io::Result<()> {
     let mut ptr = 0usize;
-    w.write_all(WITNESSCALC_GRAPH_MAGIC).unwrap();
+    w.write_all(WITNESSCALC_GRAPH_MAGIC)?;
     ptr += WITNESSCALC_GRAPH_MAGIC.len();
 
     w.write_u64::<LittleEndian>(nodes.len() as u64)?;
@@ -232,7 +262,7 @@ fn read_message<R: Read, M: Message + std::default::Default>(
     Ok(msg)
 }
 
-pub fn deserialize_witnesscalc_graph(
+pub(crate) fn deserialize_witnesscalc_graph(
     r: impl Read,
 ) -> std::io::Result<(Vec<graph::Node>, Vec<usize>, InputSignalsInfo)> {
     let mut br = WriteBackReader::new(r);
@@ -251,8 +281,7 @@ pub fn deserialize_witnesscalc_graph(
     let mut nodes = Vec::with_capacity(nodes_num as usize);
     for _ in 0..nodes_num {
         let n: proto::Node = read_message(&mut br)?;
-        let n2: graph::Node = n.into();
-        nodes.push(n2);
+        nodes.push(n.try_into()?);
     }
 
     let md: proto::GraphMetadata = read_message(&mut br)?;
@@ -331,13 +360,15 @@ impl<R: Read> Write for WriteBackReader<R> {
 }
 
 #[cfg(test)]
-mod tests {
-    use super::*;
-    use byteorder::ByteOrder;
+mod test {
     use core::str::FromStr;
-    use graph::{Operation, TresOperation, UnoOperation};
     use std::collections::HashMap;
 
+    use byteorder::ByteOrder;
+    use graph::{Operation, TresOperation, UnoOperation};
+
+    use super::*;
+
     #[test]
     fn test_read_message() {
         let mut buf = Vec::new();
@@ -419,13 +450,13 @@ mod tests {
         let mut r = WriteBackReader::new(std::io::Cursor::new(&data));
 
         let buf = &mut [0u8; 5];
-        r.read(buf).unwrap();
+        r.read_exact(buf).unwrap();
         assert_eq!(buf, &[1, 2, 3, 4, 5]);
 
         // return [4, 5] to reader
-        r.write(&buf[3..]).unwrap();
+        r.write_all(&buf[3..]).unwrap();
         // return [2, 3] to reader
-        r.write(&buf[1..3]).unwrap();
+        r.write_all(&buf[1..3]).unwrap();
 
         buf.fill(0);
 

rln/src/circuit/mod.rs

@@ -1,151 +1,140 @@
 // This crate provides interfaces for the zero-knowledge circuit and keys
 
-pub mod iden3calc;
-pub mod qap;
-pub mod zkey;
+pub(crate) mod error;
+pub(crate) mod iden3calc;
+pub(crate) mod qap;
+
+#[cfg(not(target_arch = "wasm32"))]
+use std::sync::LazyLock;
 
-use ::lazy_static::lazy_static;
 use ark_bn254::{
     Bn254, Fq as ArkFq, Fq2 as ArkFq2, Fr as ArkFr, G1Affine as ArkG1Affine,
     G1Projective as ArkG1Projective, G2Affine as ArkG2Affine, G2Projective as ArkG2Projective,
 };
-use ark_groth16::ProvingKey;
-use ark_relations::r1cs::ConstraintMatrices;
-use cfg_if::cfg_if;
-use color_eyre::{Report, Result};
-
-use crate::circuit::iden3calc::calc_witness;
-
-#[cfg(feature = "arkzkey")]
-use {
-    ark_ff::Field, ark_serialize::CanonicalDeserialize, ark_serialize::CanonicalSerialize,
-    color_eyre::eyre::WrapErr,
+use ark_ff::Field;
+use ark_groth16::{
+    Proof as ArkProof, ProvingKey as ArkProvingKey, VerifyingKey as ArkVerifyingKey,
 };
+use ark_relations::r1cs::ConstraintMatrices;
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
 
-#[cfg(not(feature = "arkzkey"))]
-use {crate::circuit::zkey::read_zkey, std::io::Cursor};
-
-#[cfg(feature = "arkzkey")]
-pub const ARKZKEY_BYTES: &[u8] = include_bytes!("../../resources/tree_height_20/rln_final.arkzkey");
-
-pub const ZKEY_BYTES: &[u8] = include_bytes!("../../resources/tree_height_20/rln_final.zkey");
+use self::error::ZKeyReadError;
 
 #[cfg(not(target_arch = "wasm32"))]
-const GRAPH_BYTES: &[u8] = include_bytes!("../../resources/tree_height_20/graph.bin");
+const GRAPH_BYTES: &[u8] = include_bytes!("../../resources/tree_depth_20/graph.bin");
 
-lazy_static! {
-    static ref ZKEY: (ProvingKey<Curve>, ConstraintMatrices<Fr>) = {
-        cfg_if! {
-                if #[cfg(feature = "arkzkey")] {
-                    read_arkzkey_from_bytes_uncompressed(ARKZKEY_BYTES).expect("Failed to read arkzkey")
-                } else {
-                    let mut reader = Cursor::new(ZKEY_BYTES);
-                    read_zkey(&mut reader).expect("Failed to read zkey")
-                }
-        }
-    };
-}
+#[cfg(not(target_arch = "wasm32"))]
+const ARKZKEY_BYTES: &[u8] = include_bytes!("../../resources/tree_depth_20/rln_final.arkzkey");
 
-pub const TEST_TREE_HEIGHT: usize = 20;
+#[cfg(not(target_arch = "wasm32"))]
+static ARKZKEY: LazyLock<Zkey> = LazyLock::new(|| {
+    read_arkzkey_from_bytes_uncompressed(ARKZKEY_BYTES).expect("Default zkey must be valid")
+});
+
+pub const DEFAULT_TREE_DEPTH: usize = 20;
+pub const COMPRESS_PROOF_SIZE: usize = 128;
 
 // The following types define the pairing friendly elliptic curve, the underlying finite fields and groups default to this module
 // Note that proofs are serialized assuming Fr to be 4x8 = 32 bytes in size. Hence, changing to a curve with different encoding will make proof verification to fail
+
+/// BN254 pairing-friendly elliptic curve.
 pub type Curve = Bn254;
+
+/// Scalar field Fr of the BN254 curve.
 pub type Fr = ArkFr;
+
+/// Base field Fq of the BN254 curve.
 pub type Fq = ArkFq;
+
+/// Quadratic extension field element for the BN254 curve.
 pub type Fq2 = ArkFq2;
+
+/// Affine representation of a G1 group element on the BN254 curve.
 pub type G1Affine = ArkG1Affine;
+
+/// Projective representation of a G1 group element on the BN254 curve.
 pub type G1Projective = ArkG1Projective;
+
+/// Affine representation of a G2 group element on the BN254 curve.
 pub type G2Affine = ArkG2Affine;
+
+/// Projective representation of a G2 group element on the BN254 curve.
 pub type G2Projective = ArkG2Projective;
 
-// Loads the proving key using a bytes vector
-pub fn zkey_from_raw(zkey_data: &[u8]) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
+/// Groth16 proof for the BN254 curve.
+pub type Proof = ArkProof<Curve>;
+
+/// Proving key for the Groth16 proof system.
+pub type ProvingKey = ArkProvingKey<Curve>;
+
+/// Combining the proving key and constraint matrices.
+pub type Zkey = (ArkProvingKey<Curve>, ConstraintMatrices<Fr>);
+
+/// Verifying key for the Groth16 proof system.
+pub type VerifyingKey = ArkVerifyingKey<Curve>;
+
+/// Loads the zkey from raw bytes
+pub fn zkey_from_raw(zkey_data: &[u8]) -> Result<Zkey, ZKeyReadError> {
     if zkey_data.is_empty() {
-        return Err(Report::msg("No proving key found!"));
+        return Err(ZKeyReadError::EmptyBytes);
     }
 
-    let proving_key_and_matrices = match () {
-        #[cfg(feature = "arkzkey")]
-        () => read_arkzkey_from_bytes_uncompressed(zkey_data)?,
-        #[cfg(not(feature = "arkzkey"))]
-        () => {
-            let mut reader = Cursor::new(zkey_data);
-            read_zkey(&mut reader)?
-        }
-    };
+    let proving_key_and_matrices = read_arkzkey_from_bytes_uncompressed(zkey_data)?;
 
     Ok(proving_key_and_matrices)
 }
 
-// Loads the proving key
+// Loads default zkey from folder
 #[cfg(not(target_arch = "wasm32"))]
-pub fn zkey_from_folder() -> &'static (ProvingKey<Curve>, ConstraintMatrices<Fr>) {
-    &ZKEY
-}
-
-pub fn calculate_rln_witness<I: IntoIterator<Item = (String, Vec<Fr>)>>(
-    inputs: I,
-    graph_data: &[u8],
-) -> Vec<Fr> {
-    calc_witness(inputs, graph_data)
+pub fn zkey_from_folder() -> &'static Zkey {
+    &ARKZKEY
 }
 
+// Loads default graph from folder
 #[cfg(not(target_arch = "wasm32"))]
 pub fn graph_from_folder() -> &'static [u8] {
     GRAPH_BYTES
 }
 
-////////////////////////////////////////////////////////
-// Functions and structs from [arkz-key](https://github.com/zkmopro/ark-zkey/blob/main/src/lib.rs#L106)
-// without print and allow to choose between compressed and uncompressed arkzkey
-////////////////////////////////////////////////////////
+// The following functions and structs are based on code from ark-zkey:
+// https://github.com/zkmopro/ark-zkey/blob/main/src/lib.rs#L106
 
-#[cfg(feature = "arkzkey")]
 #[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
-pub struct SerializableProvingKey(pub ProvingKey<Bn254>);
+struct SerializableProvingKey(ArkProvingKey<Curve>);
 
-#[cfg(feature = "arkzkey")]
 #[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
-pub struct SerializableConstraintMatrices<F: Field> {
-    pub num_instance_variables: usize,
-    pub num_witness_variables: usize,
-    pub num_constraints: usize,
-    pub a_num_non_zero: usize,
-    pub b_num_non_zero: usize,
-    pub c_num_non_zero: usize,
-    pub a: SerializableMatrix<F>,
-    pub b: SerializableMatrix<F>,
-    pub c: SerializableMatrix<F>,
+struct SerializableConstraintMatrices<F: Field> {
+    num_instance_variables: usize,
+    num_witness_variables: usize,
+    num_constraints: usize,
+    a_num_non_zero: usize,
+    b_num_non_zero: usize,
+    c_num_non_zero: usize,
+    a: SerializableMatrix<F>,
+    b: SerializableMatrix<F>,
+    c: SerializableMatrix<F>,
 }
 
-#[cfg(feature = "arkzkey")]
 #[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
-pub struct SerializableMatrix<F: Field> {
+struct SerializableMatrix<F: Field> {
     pub data: Vec<Vec<(F, usize)>>,
 }
 
-#[cfg(feature = "arkzkey")]
-pub fn read_arkzkey_from_bytes_uncompressed(
-    arkzkey_data: &[u8],
-) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
+fn read_arkzkey_from_bytes_uncompressed(arkzkey_data: &[u8]) -> Result<Zkey, ZKeyReadError> {
     if arkzkey_data.is_empty() {
-        return Err(Report::msg("No proving key found!"));
+        return Err(ZKeyReadError::EmptyBytes);
     }
 
     let mut cursor = std::io::Cursor::new(arkzkey_data);
 
     let serialized_proving_key =
-        SerializableProvingKey::deserialize_uncompressed_unchecked(&mut cursor)
-            .wrap_err("Failed to deserialize proving key")?;
+        SerializableProvingKey::deserialize_uncompressed_unchecked(&mut cursor)?;
 
     let serialized_constraint_matrices =
-        SerializableConstraintMatrices::deserialize_uncompressed_unchecked(&mut cursor)
-            .wrap_err("Failed to deserialize constraint matrices")?;
+        SerializableConstraintMatrices::deserialize_uncompressed_unchecked(&mut cursor)?;
 
-    // Get on right form for API
-    let proving_key: ProvingKey<Bn254> = serialized_proving_key.0;
-    let constraint_matrices: ConstraintMatrices<ark_bn254::Fr> = ConstraintMatrices {
+    let proving_key: ProvingKey = serialized_proving_key.0;
+    let constraint_matrices: ConstraintMatrices<Fr> = ConstraintMatrices {
         num_instance_variables: serialized_constraint_matrices.num_instance_variables,
         num_witness_variables: serialized_constraint_matrices.num_witness_variables,
         num_constraints: serialized_constraint_matrices.num_constraints,
@@ -156,6 +145,7 @@ pub fn read_arkzkey_from_bytes_uncompressed(
         b: serialized_constraint_matrices.b.data,
         c: serialized_constraint_matrices.c.data,
     };
+    let zkey = (proving_key, constraint_matrices);
 
-    Ok((proving_key, constraint_matrices))
+    Ok(zkey)
 }

rln/src/circuit/qap.rs

@@ -1,4 +1,4 @@
-// This file is based on the code by arkworks. Its preimage can be found here:
+// This crate is based on the code by arkworks. Its preimage can be found here:
 // https://github.com/arkworks-rs/circom-compat/blob/3c95ed98e23a408b4d99a53e483a9bba39685a4e/src/circom/qap.rs
 
 use ark_ff::PrimeField;
@@ -6,13 +6,18 @@ use ark_groth16::r1cs_to_qap::{evaluate_constraint, LibsnarkReduction, R1CSToQAP
 use ark_poly::EvaluationDomain;
 use ark_relations::r1cs::{ConstraintMatrices, ConstraintSystemRef, SynthesisError};
 use ark_std::{cfg_into_iter, cfg_iter, cfg_iter_mut, vec};
+#[cfg(feature = "parallel")]
+use rayon::iter::{
+    IndexedParallelIterator, IntoParallelIterator, IntoParallelRefIterator,
+    IntoParallelRefMutIterator, ParallelIterator,
+};
 
 /// Implements the witness map used by snarkjs. The arkworks witness map calculates the
 /// coefficients of H through computing (AB-C)/Z in the evaluation domain and going back to the
 /// coefficients domain. snarkjs instead precomputes the Lagrange form of the powers of tau bases
 /// in a domain twice as large and the witness map is computed as the odd coefficients of (AB-C)
 /// in that domain. This serves as HZ when computing the C proof element.
-pub struct CircomReduction;
+pub(crate) struct CircomReduction;
 
 impl R1CSToQAP for CircomReduction {
     #[allow(clippy::type_complexity)]

rln/src/circuit/zkey.rs

@@ -1,371 +0,0 @@
-// This file is based on the code by arkworks. Its preimage can be found here:
-// https://github.com/arkworks-rs/circom-compat/blob/3c95ed98e23a408b4d99a53e483a9bba39685a4e/src/zkey.rs
-
-//! ZKey Parsing
-//!
-//! Each ZKey file is broken into sections:
-//!  Header(1)
-//!       Prover Type 1 Groth
-//!  HeaderGroth(2)
-//!       n8q
-//!       q
-//!       n8r
-//!       r
-//!       NVars
-//!       NPub
-//!       DomainSize  (multiple of 2
-//!       alpha1
-//!       beta1
-//!       delta1
-//!       beta2
-//!       gamma2
-//!       delta2
-//!  IC(3)
-//!  Coefs(4)
-//!  PointsA(5)
-//!  PointsB1(6)
-//!  PointsB2(7)
-//!  PointsC(8)
-//!  PointsH(9)
-//!  Contributions(10)
-use ark_ff::{BigInteger256, PrimeField};
-use ark_relations::r1cs::ConstraintMatrices;
-use ark_serialize::{CanonicalDeserialize, SerializationError};
-use ark_std::log2;
-use byteorder::{LittleEndian, ReadBytesExt};
-
-use std::{
-    collections::HashMap,
-    io::{Read, Seek, SeekFrom},
-};
-
-use ark_bn254::{Bn254, Fq, Fq2, Fr, G1Affine, G2Affine};
-use ark_groth16::{ProvingKey, VerifyingKey};
-use num_traits::Zero;
-
-type IoResult<T> = Result<T, SerializationError>;
-
-#[derive(Clone, Debug)]
-struct Section {
-    position: u64,
-    #[allow(dead_code)]
-    size: usize,
-}
-
-/// Reads a SnarkJS ZKey file into an Arkworks ProvingKey.
-pub fn read_zkey<R: Read + Seek>(
-    reader: &mut R,
-) -> IoResult<(ProvingKey<Bn254>, ConstraintMatrices<Fr>)> {
-    let mut binfile = BinFile::new(reader)?;
-    let proving_key = binfile.proving_key()?;
-    let matrices = binfile.matrices()?;
-    Ok((proving_key, matrices))
-}
-
-#[derive(Debug)]
-struct BinFile<'a, R> {
-    #[allow(dead_code)]
-    ftype: String,
-    #[allow(dead_code)]
-    version: u32,
-    sections: HashMap<u32, Vec<Section>>,
-    reader: &'a mut R,
-}
-
-impl<'a, R: Read + Seek> BinFile<'a, R> {
-    fn new(reader: &'a mut R) -> IoResult<Self> {
-        let mut magic = [0u8; 4];
-        reader.read_exact(&mut magic)?;
-
-        let version = reader.read_u32::<LittleEndian>()?;
-
-        let num_sections = reader.read_u32::<LittleEndian>()?;
-
-        let mut sections = HashMap::new();
-        for _ in 0..num_sections {
-            let section_id = reader.read_u32::<LittleEndian>()?;
-            let section_length = reader.read_u64::<LittleEndian>()?;
-
-            let section = sections.entry(section_id).or_insert_with(Vec::new);
-            section.push(Section {
-                position: reader.stream_position()?,
-                size: section_length as usize,
-            });
-
-            reader.seek(SeekFrom::Current(section_length as i64))?;
-        }
-
-        Ok(Self {
-            ftype: std::str::from_utf8(&magic[..]).unwrap().to_string(),
-            version,
-            sections,
-            reader,
-        })
-    }
-
-    fn proving_key(&mut self) -> IoResult<ProvingKey<Bn254>> {
-        let header = self.groth_header()?;
-        let ic = self.ic(header.n_public)?;
-
-        let a_query = self.a_query(header.n_vars)?;
-        let b_g1_query = self.b_g1_query(header.n_vars)?;
-        let b_g2_query = self.b_g2_query(header.n_vars)?;
-        let l_query = self.l_query(header.n_vars - header.n_public - 1)?;
-        let h_query = self.h_query(header.domain_size as usize)?;
-
-        let vk = VerifyingKey::<Bn254> {
-            alpha_g1: header.verifying_key.alpha_g1,
-            beta_g2: header.verifying_key.beta_g2,
-            gamma_g2: header.verifying_key.gamma_g2,
-            delta_g2: header.verifying_key.delta_g2,
-            gamma_abc_g1: ic,
-        };
-
-        let pk = ProvingKey::<Bn254> {
-            vk,
-            beta_g1: header.verifying_key.beta_g1,
-            delta_g1: header.verifying_key.delta_g1,
-            a_query,
-            b_g1_query,
-            b_g2_query,
-            h_query,
-            l_query,
-        };
-
-        Ok(pk)
-    }
-
-    fn get_section(&self, id: u32) -> Section {
-        self.sections.get(&id).unwrap()[0].clone()
-    }
-
-    fn groth_header(&mut self) -> IoResult<HeaderGroth> {
-        let section = self.get_section(2);
-        let header = HeaderGroth::new(&mut self.reader, &section)?;
-        Ok(header)
-    }
-
-    fn ic(&mut self, n_public: usize) -> IoResult<Vec<G1Affine>> {
-        // the range is non-inclusive so we do +1 to get all inputs
-        self.g1_section(n_public + 1, 3)
-    }
-
-    /// Returns the [`ConstraintMatrices`] corresponding to the zkey
-    pub fn matrices(&mut self) -> IoResult<ConstraintMatrices<Fr>> {
-        let header = self.groth_header()?;
-
-        let section = self.get_section(4);
-        self.reader.seek(SeekFrom::Start(section.position))?;
-        let num_coeffs: u32 = self.reader.read_u32::<LittleEndian>()?;
-
-        // insantiate AB
-        let mut matrices = vec![vec![vec![]; header.domain_size as usize]; 2];
-        let mut max_constraint_index = 0;
-        for _ in 0..num_coeffs {
-            let matrix: u32 = self.reader.read_u32::<LittleEndian>()?;
-            let constraint: u32 = self.reader.read_u32::<LittleEndian>()?;
-            let signal: u32 = self.reader.read_u32::<LittleEndian>()?;
-
-            let value: Fr = deserialize_field_fr(&mut self.reader)?;
-            max_constraint_index = std::cmp::max(max_constraint_index, constraint);
-            matrices[matrix as usize][constraint as usize].push((value, signal as usize));
-        }
-
-        let num_constraints = max_constraint_index as usize - header.n_public;
-        // Remove the public input constraints, Arkworks adds them later
-        matrices.iter_mut().for_each(|m| {
-            m.truncate(num_constraints);
-        });
-        // This is taken from Arkworks' to_matrices() function
-        let a = matrices[0].clone();
-        let b = matrices[1].clone();
-        let a_num_non_zero: usize = a.iter().map(|lc| lc.len()).sum();
-        let b_num_non_zero: usize = b.iter().map(|lc| lc.len()).sum();
-        let matrices = ConstraintMatrices {
-            num_instance_variables: header.n_public + 1,
-            num_witness_variables: header.n_vars - header.n_public,
-            num_constraints,
-
-            a_num_non_zero,
-            b_num_non_zero,
-            c_num_non_zero: 0,
-
-            a,
-            b,
-            c: vec![],
-        };
-
-        Ok(matrices)
-    }
-
-    fn a_query(&mut self, n_vars: usize) -> IoResult<Vec<G1Affine>> {
-        self.g1_section(n_vars, 5)
-    }
-
-    fn b_g1_query(&mut self, n_vars: usize) -> IoResult<Vec<G1Affine>> {
-        self.g1_section(n_vars, 6)
-    }
-
-    fn b_g2_query(&mut self, n_vars: usize) -> IoResult<Vec<G2Affine>> {
-        self.g2_section(n_vars, 7)
-    }
-
-    fn l_query(&mut self, n_vars: usize) -> IoResult<Vec<G1Affine>> {
-        self.g1_section(n_vars, 8)
-    }
-
-    fn h_query(&mut self, n_vars: usize) -> IoResult<Vec<G1Affine>> {
-        self.g1_section(n_vars, 9)
-    }
-
-    fn g1_section(&mut self, num: usize, section_id: usize) -> IoResult<Vec<G1Affine>> {
-        let section = self.get_section(section_id as u32);
-        self.reader.seek(SeekFrom::Start(section.position))?;
-        deserialize_g1_vec(self.reader, num as u32)
-    }
-
-    fn g2_section(&mut self, num: usize, section_id: usize) -> IoResult<Vec<G2Affine>> {
-        let section = self.get_section(section_id as u32);
-        self.reader.seek(SeekFrom::Start(section.position))?;
-        deserialize_g2_vec(self.reader, num as u32)
-    }
-}
-
-#[derive(Default, Clone, Debug, CanonicalDeserialize)]
-pub struct ZVerifyingKey {
-    alpha_g1: G1Affine,
-    beta_g1: G1Affine,
-    beta_g2: G2Affine,
-    gamma_g2: G2Affine,
-    delta_g1: G1Affine,
-    delta_g2: G2Affine,
-}
-
-impl ZVerifyingKey {
-    fn new<R: Read>(reader: &mut R) -> IoResult<Self> {
-        let alpha_g1 = deserialize_g1(reader)?;
-        let beta_g1 = deserialize_g1(reader)?;
-        let beta_g2 = deserialize_g2(reader)?;
-        let gamma_g2 = deserialize_g2(reader)?;
-        let delta_g1 = deserialize_g1(reader)?;
-        let delta_g2 = deserialize_g2(reader)?;
-
-        Ok(Self {
-            alpha_g1,
-            beta_g1,
-            beta_g2,
-            gamma_g2,
-            delta_g1,
-            delta_g2,
-        })
-    }
-}
-
-#[derive(Clone, Debug)]
-struct HeaderGroth {
-    #[allow(dead_code)]
-    n8q: u32,
-    #[allow(dead_code)]
-    q: BigInteger256,
-    #[allow(dead_code)]
-    n8r: u32,
-    #[allow(dead_code)]
-    r: BigInteger256,
-
-    n_vars: usize,
-    n_public: usize,
-
-    domain_size: u32,
-    #[allow(dead_code)]
-    power: u32,
-
-    verifying_key: ZVerifyingKey,
-}
-
-impl HeaderGroth {
-    fn new<R: Read + Seek>(reader: &mut R, section: &Section) -> IoResult<Self> {
-        reader.seek(SeekFrom::Start(section.position))?;
-        Self::read(reader)
-    }
-
-    fn read<R: Read>(mut reader: &mut R) -> IoResult<Self> {
-        // TODO: Impl From<u32> in Arkworks
-        let n8q: u32 = u32::deserialize_uncompressed(&mut reader)?;
-        // group order r of Bn254
-        let q = BigInteger256::deserialize_uncompressed(&mut reader)?;
-
-        let n8r: u32 = u32::deserialize_uncompressed(&mut reader)?;
-        // Prime field modulus
-        let r = BigInteger256::deserialize_uncompressed(&mut reader)?;
-
-        let n_vars = u32::deserialize_uncompressed(&mut reader)? as usize;
-        let n_public = u32::deserialize_uncompressed(&mut reader)? as usize;
-
-        let domain_size: u32 = u32::deserialize_uncompressed(&mut reader)?;
-        let power = log2(domain_size as usize);
-
-        let verifying_key = ZVerifyingKey::new(&mut reader)?;
-
-        Ok(Self {
-            n8q,
-            q,
-            n8r,
-            r,
-            n_vars,
-            n_public,
-            domain_size,
-            power,
-            verifying_key,
-        })
-    }
-}
-
-// need to divide by R, since snarkjs outputs the zkey with coefficients
-// multiplieid by R^2
-fn deserialize_field_fr<R: Read>(reader: &mut R) -> IoResult<Fr> {
-    let bigint = BigInteger256::deserialize_uncompressed(reader)?;
-    Ok(Fr::new_unchecked(Fr::new_unchecked(bigint).into_bigint()))
-}
-
-// skips the multiplication by R because Circom points are already in Montgomery form
-fn deserialize_field<R: Read>(reader: &mut R) -> IoResult<Fq> {
-    let bigint = BigInteger256::deserialize_uncompressed(reader)?;
-    // if you use Fq::new it multiplies by R
-    Ok(Fq::new_unchecked(bigint))
-}
-
-pub fn deserialize_field2<R: Read>(reader: &mut R) -> IoResult<Fq2> {
-    let c0 = deserialize_field(reader)?;
-    let c1 = deserialize_field(reader)?;
-    Ok(Fq2::new(c0, c1))
-}
-
-fn deserialize_g1<R: Read>(reader: &mut R) -> IoResult<G1Affine> {
-    let x = deserialize_field(reader)?;
-    let y = deserialize_field(reader)?;
-    let infinity = x.is_zero() && y.is_zero();
-    if infinity {
-        Ok(G1Affine::identity())
-    } else {
-        Ok(G1Affine::new(x, y))
-    }
-}
-
-fn deserialize_g2<R: Read>(reader: &mut R) -> IoResult<G2Affine> {
-    let f1 = deserialize_field2(reader)?;
-    let f2 = deserialize_field2(reader)?;
-    let infinity = f1.is_zero() && f2.is_zero();
-    if infinity {
-        Ok(G2Affine::identity())
-    } else {
-        Ok(G2Affine::new(f1, f2))
-    }
-}
-
-fn deserialize_g1_vec<R: Read>(reader: &mut R, n_vars: u32) -> IoResult<Vec<G1Affine>> {
-    (0..n_vars).map(|_| deserialize_g1(reader)).collect()
-}
-
-fn deserialize_g2_vec<R: Read>(reader: &mut R, n_vars: u32) -> IoResult<Vec<G2Affine>> {
-    (0..n_vars).map(|_| deserialize_g2(reader)).collect()
-}

rln/src/error.rs

@@ -0,0 +1,83 @@
+use std::{array::TryFromSliceError, num::TryFromIntError};
+
+use ark_relations::r1cs::SynthesisError;
+use num_bigint::{BigInt, ParseBigIntError};
+use thiserror::Error;
+use zerokit_utils::error::{FromConfigError, HashError, ZerokitMerkleTreeError};
+
+use crate::circuit::{
+    error::{WitnessCalcError, ZKeyReadError},
+    Fr,
+};
+
+/// Errors that can occur during RLN utility operations (conversions, parsing, etc.)
+#[derive(Debug, thiserror::Error)]
+pub enum UtilsError {
+    #[error("Expected radix 10 or 16")]
+    WrongRadix,
+    #[error("Failed to parse big integer: {0}")]
+    ParseBigInt(#[from] ParseBigIntError),
+    #[error("Failed to convert to usize: {0}")]
+    ToUsize(#[from] TryFromIntError),
+    #[error("Failed to convert from slice: {0}")]
+    FromSlice(#[from] TryFromSliceError),
+    #[error("Input data too short: expected at least {expected} bytes, got {actual} bytes")]
+    InsufficientData { expected: usize, actual: usize },
+}
+
+/// Errors that can occur during RLN protocol operations (proof generation, verification, etc.)
+#[derive(Debug, thiserror::Error)]
+pub enum ProtocolError {
+    #[error("Error producing proof: {0}")]
+    Synthesis(#[from] SynthesisError),
+    #[error("RLN utility error: {0}")]
+    Utils(#[from] UtilsError),
+    #[error("Error calculating witness: {0}")]
+    WitnessCalc(#[from] WitnessCalcError),
+    #[error("Expected to read {0} bytes but read only {1} bytes")]
+    InvalidReadLen(usize, usize),
+    #[error("Cannot convert bigint {0:?} to biguint")]
+    BigUintConversion(BigInt),
+    #[error("Message id ({0}) is not within user_message_limit ({1})")]
+    InvalidMessageId(Fr, Fr),
+    #[error("Merkle proof length mismatch: expected {0}, got {1}")]
+    InvalidMerkleProofLength(usize, usize),
+    #[error("External nullifiers mismatch: {0} != {1}")]
+    ExternalNullifierMismatch(Fr, Fr),
+    #[error("Cannot recover secret: division by zero")]
+    DivisionByZero,
+    #[error("Merkle tree operation error: {0}")]
+    MerkleTree(#[from] ZerokitMerkleTreeError),
+    #[error("Hash computation error: {0}")]
+    Hash(#[from] HashError),
+    #[error("Proof serialization error: {0}")]
+    SerializationError(#[from] ark_serialize::SerializationError),
+}
+
+/// Errors that can occur during proof verification
+#[derive(Error, Debug)]
+pub enum VerifyError {
+    #[error("Invalid proof provided")]
+    InvalidProof,
+    #[error("Expected one of the provided roots")]
+    InvalidRoot,
+    #[error("Signal value does not match")]
+    InvalidSignal,
+}
+
+/// Top-level RLN error type encompassing all RLN operations
+#[derive(Debug, thiserror::Error)]
+pub enum RLNError {
+    #[error("Configuration error: {0}")]
+    Config(#[from] FromConfigError),
+    #[error("Merkle tree error: {0}")]
+    MerkleTree(#[from] ZerokitMerkleTreeError),
+    #[error("Hash error: {0}")]
+    Hash(#[from] HashError),
+    #[error("ZKey error: {0}")]
+    ZKey(#[from] ZKeyReadError),
+    #[error("Protocol error: {0}")]
+    Protocol(#[from] ProtocolError),
+    #[error("Verification error: {0}")]
+    Verify(#[from] VerifyError),
+}

rln/src/ffi.rs

@@ -1,547 +0,0 @@
-// This crate implements the public Foreign Function Interface (FFI) for the RLN module
-
-use std::slice;
-
-use crate::public::{hash as public_hash, poseidon_hash as public_poseidon_hash, RLN};
-
-// Macro to call methods with arbitrary amount of arguments,
-// First argument to the macro is context,
-// second is the actual method on `RLN`
-// rest are all other arguments to the method
-#[cfg(not(feature = "stateless"))]
-macro_rules! call {
-    ($instance:expr, $method:ident $(, $arg:expr)*) => {
-        {
-            let new_instance: &mut RLN = $instance.process();
-            match new_instance.$method($($arg.process()),*) {
-                Ok(()) => {
-                    true
-                }
-                Err(err) => {
-                    eprintln!("execution error: {err}");
-                    false
-                }
-            }
-        }
-    }
-}
-
-// Macro to call methods with arbitrary amount of arguments,
-// which have the last argument is output buffer pointer
-// First argument to the macro is context,
-// second is the actual method on `RLN`
-// third is the aforementioned output buffer argument
-// rest are all other arguments to the method
-macro_rules! call_with_output_arg {
-    // this variant is needed for the case when
-    // there are zero other arguments
-    ($instance:expr, $method:ident, $output_arg:expr) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            let new_instance = $instance.process();
-            match new_instance.$method(&mut output_data) {
-                Ok(()) => {
-                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                    std::mem::forget(output_data);
-                    true
-                }
-                Err(err) => {
-                    std::mem::forget(output_data);
-                    eprintln!("execution error: {err}");
-                    false
-                }
-            }
-        }
-    };
-    ($instance:expr, $method:ident, $output_arg:expr, $( $arg:expr ),* ) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            let new_instance = $instance.process();
-            match new_instance.$method($($arg.process()),*, &mut output_data) {
-                Ok(()) => {
-                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                    std::mem::forget(output_data);
-                    true
-                }
-                Err(err) => {
-                    std::mem::forget(output_data);
-                    eprintln!("execution error: {err}");
-                    false
-                }
-            }
-        }
-    };
-
-}
-
-// Macro to call methods with arbitrary amount of arguments,
-// which are not implemented in a ctx RLN object
-// First argument is the method to call
-// Second argument is the output buffer argument
-// The remaining arguments are all other inputs to the method
-macro_rules! no_ctx_call_with_output_arg {
-    ($method:ident, $output_arg:expr, $( $arg:expr ),* ) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            match $method($($arg.process()),*, &mut output_data) {
-                Ok(()) => {
-                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                    std::mem::forget(output_data);
-                    true
-                }
-                Err(err) => {
-                    std::mem::forget(output_data);
-                    eprintln!("execution error: {err}");
-                    false
-                }
-            }
-        }
-    }
-}
-
-// Macro to call methods with arbitrary amount of arguments,
-// which have the last argument as bool
-// First argument to the macro is context,
-// second is the actual method on `RLN`
-// third is the aforementioned bool argument
-// rest are all other arguments to the method
-macro_rules! call_with_bool_arg {
-    ($instance:expr, $method:ident, $bool_arg:expr, $( $arg:expr ),* ) => {
-        {
-            let new_instance = $instance.process();
-            if match new_instance.$method($($arg.process()),*,) {
-                Ok(result) => result,
-                Err(err) => {
-                    eprintln!("execution error: {err}");
-                    return false
-                },
-            } {
-                unsafe { *$bool_arg = true };
-            } else {
-                unsafe { *$bool_arg = false };
-            };
-            true
-        }
-    }
-}
-
-trait ProcessArg {
-    type ReturnType;
-    fn process(self) -> Self::ReturnType;
-}
-
-impl ProcessArg for usize {
-    type ReturnType = usize;
-    fn process(self) -> Self::ReturnType {
-        self
-    }
-}
-
-impl ProcessArg for *const Buffer {
-    type ReturnType = &'static [u8];
-    fn process(self) -> Self::ReturnType {
-        <&[u8]>::from(unsafe { &*self })
-    }
-}
-
-impl ProcessArg for *const RLN {
-    type ReturnType = &'static RLN;
-    fn process(self) -> Self::ReturnType {
-        unsafe { &*self }
-    }
-}
-
-impl ProcessArg for *mut RLN {
-    type ReturnType = &'static mut RLN;
-    fn process(self) -> Self::ReturnType {
-        unsafe { &mut *self }
-    }
-}
-
-///// Buffer struct is taken from
-///// <https://github.com/celo-org/celo-threshold-bls-rs/blob/master/crates/threshold-bls-ffi/src/ffi.rs>
-/////
-///// Also heavily inspired by <https://github.com/kilic/rln/blob/master/src/ffi.rs>
-
-#[repr(C)]
-#[derive(Clone, Debug, PartialEq)]
-pub struct Buffer {
-    pub ptr: *const u8,
-    pub len: usize,
-}
-
-impl From<&[u8]> for Buffer {
-    fn from(src: &[u8]) -> Self {
-        Self {
-            ptr: src.as_ptr(),
-            len: src.len(),
-        }
-    }
-}
-
-impl<'a> From<&Buffer> for &'a [u8] {
-    fn from(src: &Buffer) -> &'a [u8] {
-        unsafe { slice::from_raw_parts(src.ptr, src.len) }
-    }
-}
-
-// TODO: check if there are security implications by using this clippy
-// #[allow(clippy::not_unsafe_ptr_arg_deref)]
-
-////////////////////////////////////////////////////////
-// RLN APIs
-////////////////////////////////////////////////////////
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[cfg(not(feature = "stateless"))]
-#[no_mangle]
-pub extern "C" fn new(tree_height: usize, input_buffer: *const Buffer, ctx: *mut *mut RLN) -> bool {
-    match RLN::new(tree_height, input_buffer.process()) {
-        Ok(rln) => {
-            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-            true
-        }
-        Err(err) => {
-            eprintln!("could not instantiate rln: {err}");
-            false
-        }
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[cfg(feature = "stateless")]
-#[no_mangle]
-pub extern "C" fn new(ctx: *mut *mut RLN) -> bool {
-    match RLN::new() {
-        Ok(rln) => {
-            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-            true
-        }
-        Err(err) => {
-            eprintln!("could not instantiate rln: {err}");
-            false
-        }
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[cfg(not(feature = "stateless"))]
-#[no_mangle]
-pub extern "C" fn new_with_params(
-    tree_height: usize,
-    zkey_buffer: *const Buffer,
-    graph_data: *const Buffer,
-    tree_config: *const Buffer,
-    ctx: *mut *mut RLN,
-) -> bool {
-    match RLN::new_with_params(
-        tree_height,
-        zkey_buffer.process().to_vec(),
-        graph_data.process().to_vec(),
-        tree_config.process(),
-    ) {
-        Ok(rln) => {
-            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-            true
-        }
-        Err(err) => {
-            eprintln!("could not instantiate rln: {err}");
-            false
-        }
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[cfg(feature = "stateless")]
-#[no_mangle]
-pub extern "C" fn new_with_params(
-    zkey_buffer: *const Buffer,
-    graph_buffer: *const Buffer,
-    ctx: *mut *mut RLN,
-) -> bool {
-    match RLN::new_with_params(
-        zkey_buffer.process().to_vec(),
-        graph_buffer.process().to_vec(),
-    ) {
-        Ok(rln) => {
-            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-            true
-        }
-        Err(err) => {
-            eprintln!("could not instantiate rln: {err}");
-            false
-        }
-    }
-}
-
-////////////////////////////////////////////////////////
-// Merkle tree APIs
-////////////////////////////////////////////////////////
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn set_tree(ctx: *mut RLN, tree_height: usize) -> bool {
-    call!(ctx, set_tree, tree_height)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn delete_leaf(ctx: *mut RLN, index: usize) -> bool {
-    call!(ctx, delete_leaf, index)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn set_leaf(ctx: *mut RLN, index: usize, input_buffer: *const Buffer) -> bool {
-    call!(ctx, set_leaf, index, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn get_leaf(ctx: *mut RLN, index: usize, output_buffer: *mut Buffer) -> bool {
-    call_with_output_arg!(ctx, get_leaf, output_buffer, index)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn leaves_set(ctx: *mut RLN) -> usize {
-    ctx.process().leaves_set()
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn set_next_leaf(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
-    call!(ctx, set_next_leaf, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn set_leaves_from(
-    ctx: *mut RLN,
-    index: usize,
-    input_buffer: *const Buffer,
-) -> bool {
-    call!(ctx, set_leaves_from, index, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn init_tree_with_leaves(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
-    call!(ctx, init_tree_with_leaves, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn atomic_operation(
-    ctx: *mut RLN,
-    index: usize,
-    leaves_buffer: *const Buffer,
-    indices_buffer: *const Buffer,
-) -> bool {
-    call!(ctx, atomic_operation, index, leaves_buffer, indices_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn seq_atomic_operation(
-    ctx: *mut RLN,
-    leaves_buffer: *const Buffer,
-    indices_buffer: *const Buffer,
-) -> bool {
-    call!(
-        ctx,
-        atomic_operation,
-        ctx.process().leaves_set(),
-        leaves_buffer,
-        indices_buffer
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn get_root(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
-    call_with_output_arg!(ctx, get_root, output_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn get_proof(ctx: *const RLN, index: usize, output_buffer: *mut Buffer) -> bool {
-    call_with_output_arg!(ctx, get_proof, output_buffer, index)
-}
-
-////////////////////////////////////////////////////////
-// zkSNARKs APIs
-////////////////////////////////////////////////////////
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn prove(
-    ctx: *mut RLN,
-    input_buffer: *const Buffer,
-    output_buffer: *mut Buffer,
-) -> bool {
-    call_with_output_arg!(ctx, prove, output_buffer, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn verify(
-    ctx: *const RLN,
-    proof_buffer: *const Buffer,
-    proof_is_valid_ptr: *mut bool,
-) -> bool {
-    call_with_bool_arg!(ctx, verify, proof_is_valid_ptr, proof_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn generate_rln_proof(
-    ctx: *mut RLN,
-    input_buffer: *const Buffer,
-    output_buffer: *mut Buffer,
-) -> bool {
-    call_with_output_arg!(ctx, generate_rln_proof, output_buffer, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn generate_rln_proof_with_witness(
-    ctx: *mut RLN,
-    input_buffer: *const Buffer,
-    output_buffer: *mut Buffer,
-) -> bool {
-    call_with_output_arg!(
-        ctx,
-        generate_rln_proof_with_witness,
-        output_buffer,
-        input_buffer
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn verify_rln_proof(
-    ctx: *const RLN,
-    proof_buffer: *const Buffer,
-    proof_is_valid_ptr: *mut bool,
-) -> bool {
-    call_with_bool_arg!(ctx, verify_rln_proof, proof_is_valid_ptr, proof_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn verify_with_roots(
-    ctx: *const RLN,
-    proof_buffer: *const Buffer,
-    roots_buffer: *const Buffer,
-    proof_is_valid_ptr: *mut bool,
-) -> bool {
-    call_with_bool_arg!(
-        ctx,
-        verify_with_roots,
-        proof_is_valid_ptr,
-        proof_buffer,
-        roots_buffer
-    )
-}
-
-////////////////////////////////////////////////////////
-// Utils
-////////////////////////////////////////////////////////
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn key_gen(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
-    call_with_output_arg!(ctx, key_gen, output_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn seeded_key_gen(
-    ctx: *const RLN,
-    input_buffer: *const Buffer,
-    output_buffer: *mut Buffer,
-) -> bool {
-    call_with_output_arg!(ctx, seeded_key_gen, output_buffer, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn extended_key_gen(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
-    call_with_output_arg!(ctx, extended_key_gen, output_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn seeded_extended_key_gen(
-    ctx: *const RLN,
-    input_buffer: *const Buffer,
-    output_buffer: *mut Buffer,
-) -> bool {
-    call_with_output_arg!(ctx, seeded_extended_key_gen, output_buffer, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn recover_id_secret(
-    ctx: *const RLN,
-    input_proof_buffer_1: *const Buffer,
-    input_proof_buffer_2: *const Buffer,
-    output_buffer: *mut Buffer,
-) -> bool {
-    call_with_output_arg!(
-        ctx,
-        recover_id_secret,
-        output_buffer,
-        input_proof_buffer_1,
-        input_proof_buffer_2
-    )
-}
-
-////////////////////////////////////////////////////////
-// Persistent metadata APIs
-////////////////////////////////////////////////////////
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn set_metadata(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
-    call!(ctx, set_metadata, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn get_metadata(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
-    call_with_output_arg!(ctx, get_metadata, output_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-#[cfg(not(feature = "stateless"))]
-pub extern "C" fn flush(ctx: *mut RLN) -> bool {
-    call!(ctx, flush)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn hash(input_buffer: *const Buffer, output_buffer: *mut Buffer) -> bool {
-    no_ctx_call_with_output_arg!(public_hash, output_buffer, input_buffer)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn poseidon_hash(input_buffer: *const Buffer, output_buffer: *mut Buffer) -> bool {
-    no_ctx_call_with_output_arg!(public_poseidon_hash, output_buffer, input_buffer)
-}

rln/src/ffi/ffi_rln.rs

@@ -0,0 +1,566 @@
+#![allow(non_camel_case_types)]
+
+use num_bigint::BigInt;
+use safer_ffi::{boxed::Box_, derive_ReprC, ffi_export, prelude::repr_c};
+#[cfg(not(feature = "stateless"))]
+use {safer_ffi::prelude::char_p, std::fs::File, std::io::Read};
+
+use super::ffi_utils::{CBoolResult, CFr, CResult};
+use crate::prelude::*;
+
+#[cfg(not(feature = "stateless"))]
+const MAX_CONFIG_SIZE: u64 = 1024 * 1024; // 1MB
+
+// FFI_RLN
+
+#[derive_ReprC]
+#[repr(opaque)]
+pub struct FFI_RLN(pub(crate) RLN);
+
+// RLN initialization APIs
+
+#[cfg(not(feature = "stateless"))]
+#[ffi_export]
+pub fn ffi_rln_new(
+    tree_depth: usize,
+    config_path: char_p::Ref<'_>,
+) -> CResult<repr_c::Box<FFI_RLN>, repr_c::String> {
+    let config_str = File::open(config_path.to_str())
+        .and_then(|mut file| {
+            let metadata = file.metadata()?;
+            if metadata.len() > MAX_CONFIG_SIZE {
+                return Err(std::io::Error::new(
+                    std::io::ErrorKind::InvalidData,
+                    format!(
+                        "Config file too large: {} bytes (max {} bytes)",
+                        metadata.len(),
+                        MAX_CONFIG_SIZE
+                    ),
+                ));
+            }
+            let mut s = String::new();
+            file.read_to_string(&mut s)?;
+            Ok(s)
+        })
+        .unwrap_or_default();
+
+    match RLN::new(tree_depth, config_str.as_str()) {
+        Ok(rln) => CResult {
+            ok: Some(Box_::new(FFI_RLN(rln))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[cfg(feature = "stateless")]
+#[ffi_export]
+pub fn ffi_rln_new() -> CResult<repr_c::Box<FFI_RLN>, repr_c::String> {
+    match RLN::new() {
+        Ok(rln) => CResult {
+            ok: Some(Box_::new(FFI_RLN(rln))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[cfg(not(feature = "stateless"))]
+#[ffi_export]
+pub fn ffi_rln_new_with_params(
+    tree_depth: usize,
+    zkey_data: &repr_c::Vec<u8>,
+    graph_data: &repr_c::Vec<u8>,
+    config_path: char_p::Ref<'_>,
+) -> CResult<repr_c::Box<FFI_RLN>, repr_c::String> {
+    let config_str = File::open(config_path.to_str())
+        .and_then(|mut file| {
+            let metadata = file.metadata()?;
+            if metadata.len() > MAX_CONFIG_SIZE {
+                return Err(std::io::Error::new(
+                    std::io::ErrorKind::InvalidData,
+                    format!(
+                        "Config file too large: {} bytes (max {} bytes)",
+                        metadata.len(),
+                        MAX_CONFIG_SIZE
+                    ),
+                ));
+            }
+            let mut s = String::new();
+            file.read_to_string(&mut s)?;
+            Ok(s)
+        })
+        .unwrap_or_default();
+
+    match RLN::new_with_params(
+        tree_depth,
+        zkey_data.to_vec(),
+        graph_data.to_vec(),
+        config_str.as_str(),
+    ) {
+        Ok(rln) => CResult {
+            ok: Some(Box_::new(FFI_RLN(rln))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[cfg(feature = "stateless")]
+#[ffi_export]
+pub fn ffi_rln_new_with_params(
+    zkey_data: &repr_c::Vec<u8>,
+    graph_data: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Box<FFI_RLN>, repr_c::String> {
+    match RLN::new_with_params(zkey_data.to_vec(), graph_data.to_vec()) {
+        Ok(rln) => CResult {
+            ok: Some(Box_::new(FFI_RLN(rln))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_rln_free(rln: repr_c::Box<FFI_RLN>) {
+    drop(rln);
+}
+
+// RLNProof
+
+#[derive_ReprC]
+#[repr(opaque)]
+pub struct FFI_RLNProof(pub(crate) RLNProof);
+
+#[ffi_export]
+pub fn ffi_rln_proof_get_values(
+    rln_proof: &repr_c::Box<FFI_RLNProof>,
+) -> repr_c::Box<FFI_RLNProofValues> {
+    Box_::new(FFI_RLNProofValues(rln_proof.0.proof_values))
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_to_bytes_le(
+    rln_proof: &repr_c::Box<FFI_RLNProof>,
+) -> CResult<repr_c::Vec<u8>, repr_c::String> {
+    match rln_proof_to_bytes_le(&rln_proof.0) {
+        Ok(bytes) => CResult {
+            ok: Some(bytes.into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_to_bytes_be(
+    rln_proof: &repr_c::Box<FFI_RLNProof>,
+) -> CResult<repr_c::Vec<u8>, repr_c::String> {
+    match rln_proof_to_bytes_be(&rln_proof.0) {
+        Ok(bytes) => CResult {
+            ok: Some(bytes.into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_bytes_le_to_rln_proof(
+    bytes: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Box<FFI_RLNProof>, repr_c::String> {
+    match bytes_le_to_rln_proof(bytes) {
+        Ok((rln_proof, _)) => CResult {
+            ok: Some(Box_::new(FFI_RLNProof(rln_proof))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_bytes_be_to_rln_proof(
+    bytes: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Box<FFI_RLNProof>, repr_c::String> {
+    match bytes_be_to_rln_proof(bytes) {
+        Ok((rln_proof, _)) => CResult {
+            ok: Some(Box_::new(FFI_RLNProof(rln_proof))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_free(rln_proof: repr_c::Box<FFI_RLNProof>) {
+    drop(rln_proof);
+}
+
+// RLNWitnessInput
+
+#[derive_ReprC]
+#[repr(opaque)]
+pub struct FFI_RLNWitnessInput(pub(crate) RLNWitnessInput);
+
+#[ffi_export]
+pub fn ffi_rln_witness_input_new(
+    identity_secret: &CFr,
+    user_message_limit: &CFr,
+    message_id: &CFr,
+    path_elements: &repr_c::Vec<CFr>,
+    identity_path_index: &repr_c::Vec<u8>,
+    x: &CFr,
+    external_nullifier: &CFr,
+) -> CResult<repr_c::Box<FFI_RLNWitnessInput>, repr_c::String> {
+    let mut identity_secret_fr = identity_secret.0;
+    let path_elements: Vec<Fr> = path_elements.iter().map(|cfr| cfr.0).collect();
+    let identity_path_index: Vec<u8> = identity_path_index.iter().copied().collect();
+    match RLNWitnessInput::new(
+        IdSecret::from(&mut identity_secret_fr),
+        user_message_limit.0,
+        message_id.0,
+        path_elements,
+        identity_path_index,
+        x.0,
+        external_nullifier.0,
+    ) {
+        Ok(witness) => CResult {
+            ok: Some(Box_::new(FFI_RLNWitnessInput(witness))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_rln_witness_to_bytes_le(
+    witness: &repr_c::Box<FFI_RLNWitnessInput>,
+) -> CResult<repr_c::Vec<u8>, repr_c::String> {
+    match rln_witness_to_bytes_le(&witness.0) {
+        Ok(bytes) => CResult {
+            ok: Some(bytes.into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_rln_witness_to_bytes_be(
+    witness: &repr_c::Box<FFI_RLNWitnessInput>,
+) -> CResult<repr_c::Vec<u8>, repr_c::String> {
+    match rln_witness_to_bytes_be(&witness.0) {
+        Ok(bytes) => CResult {
+            ok: Some(bytes.into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_bytes_le_to_rln_witness(
+    bytes: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Box<FFI_RLNWitnessInput>, repr_c::String> {
+    match bytes_le_to_rln_witness(bytes) {
+        Ok((witness, _)) => CResult {
+            ok: Some(Box_::new(FFI_RLNWitnessInput(witness))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_bytes_be_to_rln_witness(
+    bytes: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Box<FFI_RLNWitnessInput>, repr_c::String> {
+    match bytes_be_to_rln_witness(bytes) {
+        Ok((witness, _)) => CResult {
+            ok: Some(Box_::new(FFI_RLNWitnessInput(witness))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_rln_witness_to_bigint_json(
+    witness: &repr_c::Box<FFI_RLNWitnessInput>,
+) -> CResult<repr_c::String, repr_c::String> {
+    match rln_witness_to_bigint_json(&witness.0) {
+        Ok(json) => CResult {
+            ok: Some(json.to_string().into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_rln_witness_input_free(witness: repr_c::Box<FFI_RLNWitnessInput>) {
+    drop(witness);
+}
+
+// RLNProofValues
+
+#[derive_ReprC]
+#[repr(opaque)]
+pub struct FFI_RLNProofValues(pub(crate) RLNProofValues);
+
+#[ffi_export]
+pub fn ffi_rln_proof_values_get_y(pv: &repr_c::Box<FFI_RLNProofValues>) -> repr_c::Box<CFr> {
+    CFr::from(pv.0.y).into()
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_values_get_nullifier(
+    pv: &repr_c::Box<FFI_RLNProofValues>,
+) -> repr_c::Box<CFr> {
+    CFr::from(pv.0.nullifier).into()
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_values_get_root(pv: &repr_c::Box<FFI_RLNProofValues>) -> repr_c::Box<CFr> {
+    CFr::from(pv.0.root).into()
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_values_get_x(pv: &repr_c::Box<FFI_RLNProofValues>) -> repr_c::Box<CFr> {
+    CFr::from(pv.0.x).into()
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_values_get_external_nullifier(
+    pv: &repr_c::Box<FFI_RLNProofValues>,
+) -> repr_c::Box<CFr> {
+    CFr::from(pv.0.external_nullifier).into()
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_values_to_bytes_le(pv: &repr_c::Box<FFI_RLNProofValues>) -> repr_c::Vec<u8> {
+    rln_proof_values_to_bytes_le(&pv.0).into()
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_values_to_bytes_be(pv: &repr_c::Box<FFI_RLNProofValues>) -> repr_c::Vec<u8> {
+    rln_proof_values_to_bytes_be(&pv.0).into()
+}
+
+#[ffi_export]
+pub fn ffi_bytes_le_to_rln_proof_values(
+    bytes: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Box<FFI_RLNProofValues>, repr_c::String> {
+    match bytes_le_to_rln_proof_values(bytes) {
+        Ok((pv, _)) => CResult {
+            ok: Some(Box_::new(FFI_RLNProofValues(pv))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_bytes_be_to_rln_proof_values(
+    bytes: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Box<FFI_RLNProofValues>, repr_c::String> {
+    match bytes_be_to_rln_proof_values(bytes) {
+        Ok((pv, _)) => CResult {
+            ok: Some(Box_::new(FFI_RLNProofValues(pv))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_rln_proof_values_free(proof_values: repr_c::Box<FFI_RLNProofValues>) {
+    drop(proof_values);
+}
+
+// Proof generation APIs
+
+#[ffi_export]
+pub fn ffi_generate_rln_proof(
+    rln: &repr_c::Box<FFI_RLN>,
+    witness: &repr_c::Box<FFI_RLNWitnessInput>,
+) -> CResult<repr_c::Box<FFI_RLNProof>, repr_c::String> {
+    match rln.0.generate_rln_proof(&witness.0) {
+        Ok((proof, proof_values)) => {
+            let rln_proof = RLNProof {
+                proof_values,
+                proof,
+            };
+            CResult {
+                ok: Some(Box_::new(FFI_RLNProof(rln_proof))),
+                err: None,
+            }
+        }
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_generate_rln_proof_with_witness(
+    rln: &repr_c::Box<FFI_RLN>,
+    calculated_witness: &repr_c::Vec<repr_c::String>,
+    witness: &repr_c::Box<FFI_RLNWitnessInput>,
+) -> CResult<repr_c::Box<FFI_RLNProof>, repr_c::String> {
+    let calculated_witness_bigint: Result<Vec<BigInt>, _> = calculated_witness
+        .iter()
+        .map(|s| {
+            let s_str = unsafe { std::str::from_utf8_unchecked(s.as_bytes()) };
+            s_str.parse::<BigInt>()
+        })
+        .collect();
+
+    let calculated_witness_bigint = match calculated_witness_bigint {
+        Ok(w) => w,
+        Err(err) => {
+            return CResult {
+                ok: None,
+                err: Some(format!("Failed to parse witness: {}", err).into()),
+            }
+        }
+    };
+
+    match rln
+        .0
+        .generate_rln_proof_with_witness(calculated_witness_bigint, &witness.0)
+    {
+        Ok((proof, proof_values)) => {
+            let rln_proof = RLNProof {
+                proof_values,
+                proof,
+            };
+            CResult {
+                ok: Some(Box_::new(FFI_RLNProof(rln_proof))),
+                err: None,
+            }
+        }
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+// Proof verification APIs
+
+#[cfg(not(feature = "stateless"))]
+#[ffi_export]
+pub fn ffi_verify_rln_proof(
+    rln: &repr_c::Box<FFI_RLN>,
+    rln_proof: &repr_c::Box<FFI_RLNProof>,
+    x: &CFr,
+) -> CBoolResult {
+    match rln
+        .0
+        .verify_rln_proof(&rln_proof.0.proof, &rln_proof.0.proof_values, &x.0)
+    {
+        Ok(verified) => CBoolResult {
+            ok: verified,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_verify_with_roots(
+    rln: &repr_c::Box<FFI_RLN>,
+    rln_proof: &repr_c::Box<FFI_RLNProof>,
+    roots: &repr_c::Vec<CFr>,
+    x: &CFr,
+) -> CBoolResult {
+    let roots_fr: Vec<Fr> = roots.iter().map(|cfr| cfr.0).collect();
+
+    match rln.0.verify_with_roots(
+        &rln_proof.0.proof,
+        &rln_proof.0.proof_values,
+        &x.0,
+        &roots_fr,
+    ) {
+        Ok(verified) => CBoolResult {
+            ok: verified,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+// Identity secret recovery API
+
+#[ffi_export]
+pub fn ffi_recover_id_secret(
+    proof_values_1: &repr_c::Box<FFI_RLNProofValues>,
+    proof_values_2: &repr_c::Box<FFI_RLNProofValues>,
+) -> CResult<repr_c::Box<CFr>, repr_c::String> {
+    match recover_id_secret(&proof_values_1.0, &proof_values_2.0) {
+        Ok(secret) => CResult {
+            ok: Some(Box_::new(CFr::from(*secret))),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}

rln/src/ffi/ffi_tree.rs

@@ -0,0 +1,269 @@
+#![allow(non_camel_case_types)]
+#![cfg(not(feature = "stateless"))]
+
+use safer_ffi::{boxed::Box_, derive_ReprC, ffi_export, prelude::repr_c};
+
+use super::{
+    ffi_rln::FFI_RLN,
+    ffi_utils::{CBoolResult, CFr, CResult},
+};
+
+// MerkleProof
+
+#[derive_ReprC]
+#[repr(C)]
+pub struct FFI_MerkleProof {
+    pub path_elements: repr_c::Vec<CFr>,
+    pub path_index: repr_c::Vec<u8>,
+}
+
+#[ffi_export]
+pub fn ffi_merkle_proof_free(merkle_proof: repr_c::Box<FFI_MerkleProof>) {
+    drop(merkle_proof);
+}
+
+// Merkle tree management APIs
+
+#[ffi_export]
+pub fn ffi_set_tree(rln: &mut repr_c::Box<FFI_RLN>, tree_depth: usize) -> CBoolResult {
+    match rln.0.set_tree(tree_depth) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+// Merkle tree leaf operations
+
+#[ffi_export]
+pub fn ffi_delete_leaf(rln: &mut repr_c::Box<FFI_RLN>, index: usize) -> CBoolResult {
+    match rln.0.delete_leaf(index) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_set_leaf(rln: &mut repr_c::Box<FFI_RLN>, index: usize, leaf: &CFr) -> CBoolResult {
+    match rln.0.set_leaf(index, leaf.0) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_get_leaf(
+    rln: &repr_c::Box<FFI_RLN>,
+    index: usize,
+) -> CResult<repr_c::Box<CFr>, repr_c::String> {
+    match rln.0.get_leaf(index) {
+        Ok(leaf) => CResult {
+            ok: Some(CFr::from(leaf).into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_leaves_set(rln: &repr_c::Box<FFI_RLN>) -> usize {
+    rln.0.leaves_set()
+}
+
+#[ffi_export]
+pub fn ffi_set_next_leaf(rln: &mut repr_c::Box<FFI_RLN>, leaf: &CFr) -> CBoolResult {
+    match rln.0.set_next_leaf(leaf.0) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_set_leaves_from(
+    rln: &mut repr_c::Box<FFI_RLN>,
+    index: usize,
+    leaves: &repr_c::Vec<CFr>,
+) -> CBoolResult {
+    let leaves_vec: Vec<_> = leaves.iter().map(|cfr| cfr.0).collect();
+    match rln.0.set_leaves_from(index, leaves_vec) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_init_tree_with_leaves(
+    rln: &mut repr_c::Box<FFI_RLN>,
+    leaves: &repr_c::Vec<CFr>,
+) -> CBoolResult {
+    let leaves_vec: Vec<_> = leaves.iter().map(|cfr| cfr.0).collect();
+    match rln.0.init_tree_with_leaves(leaves_vec) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+// Atomic operations
+
+#[ffi_export]
+pub fn ffi_atomic_operation(
+    rln: &mut repr_c::Box<FFI_RLN>,
+    index: usize,
+    leaves: &repr_c::Vec<CFr>,
+    indices: &repr_c::Vec<usize>,
+) -> CBoolResult {
+    let leaves_vec: Vec<_> = leaves.iter().map(|cfr| cfr.0).collect();
+    let indices_vec: Vec<_> = indices.iter().copied().collect();
+    match rln.0.atomic_operation(index, leaves_vec, indices_vec) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_seq_atomic_operation(
+    rln: &mut repr_c::Box<FFI_RLN>,
+    leaves: &repr_c::Vec<CFr>,
+    indices: &repr_c::Vec<u8>,
+) -> CBoolResult {
+    let index = rln.0.leaves_set();
+    let leaves_vec: Vec<_> = leaves.iter().map(|cfr| cfr.0).collect();
+    let indices_vec: Vec<_> = indices.iter().map(|x| *x as usize).collect();
+    match rln.0.atomic_operation(index, leaves_vec, indices_vec) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+// Root and proof operations
+
+#[ffi_export]
+pub fn ffi_get_root(rln: &repr_c::Box<FFI_RLN>) -> repr_c::Box<CFr> {
+    CFr::from(rln.0.get_root()).into()
+}
+
+#[ffi_export]
+pub fn ffi_get_merkle_proof(
+    rln: &repr_c::Box<FFI_RLN>,
+    index: usize,
+) -> CResult<repr_c::Box<FFI_MerkleProof>, repr_c::String> {
+    match rln.0.get_merkle_proof(index) {
+        Ok((path_elements, path_index)) => {
+            let path_elements: repr_c::Vec<CFr> = path_elements
+                .iter()
+                .map(|fr| CFr::from(*fr))
+                .collect::<Vec<_>>()
+                .into();
+
+            let path_index: repr_c::Vec<u8> = path_index.into();
+
+            let merkle_proof = FFI_MerkleProof {
+                path_elements,
+                path_index,
+            };
+
+            CResult {
+                ok: Some(Box_::new(merkle_proof)),
+                err: None,
+            }
+        }
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+// Persistent metadata APIs
+
+#[ffi_export]
+pub fn ffi_set_metadata(rln: &mut repr_c::Box<FFI_RLN>, metadata: &repr_c::Vec<u8>) -> CBoolResult {
+    match rln.0.set_metadata(metadata) {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_get_metadata(rln: &repr_c::Box<FFI_RLN>) -> CResult<repr_c::Vec<u8>, repr_c::String> {
+    match rln.0.get_metadata() {
+        Ok(metadata) => CResult {
+            ok: Some(metadata.into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_flush(rln: &mut repr_c::Box<FFI_RLN>) -> CBoolResult {
+    match rln.0.flush() {
+        Ok(_) => CBoolResult {
+            ok: true,
+            err: None,
+        },
+        Err(err) => CBoolResult {
+            ok: false,
+            err: Some(err.to_string().into()),
+        },
+    }
+}

rln/src/ffi/ffi_utils.rs

@@ -0,0 +1,407 @@
+#![allow(non_camel_case_types)]
+
+use std::ops::Deref;
+
+use safer_ffi::{
+    boxed::Box_,
+    derive_ReprC, ffi_export,
+    prelude::{repr_c, ReprC},
+};
+
+use crate::prelude::*;
+
+// CResult
+
+#[derive_ReprC]
+#[repr(C)]
+pub struct CResult<T: ReprC, Err: ReprC> {
+    pub ok: Option<T>,
+    pub err: Option<Err>,
+}
+
+// CBoolResult
+
+#[derive_ReprC]
+#[repr(C)]
+pub struct CBoolResult {
+    pub ok: bool,
+    pub err: Option<repr_c::String>,
+}
+
+// CFr
+
+#[derive_ReprC]
+#[repr(opaque)]
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub struct CFr(pub(crate) Fr);
+
+impl Deref for CFr {
+    type Target = Fr;
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl From<Fr> for CFr {
+    fn from(fr: Fr) -> Self {
+        Self(fr)
+    }
+}
+
+impl From<CFr> for repr_c::Box<CFr> {
+    fn from(cfr: CFr) -> Self {
+        Box_::new(cfr)
+    }
+}
+
+impl From<&CFr> for repr_c::Box<CFr> {
+    fn from(cfr: &CFr) -> Self {
+        CFr(cfr.0).into()
+    }
+}
+
+impl PartialEq<Fr> for CFr {
+    fn eq(&self, other: &Fr) -> bool {
+        self.0 == *other
+    }
+}
+
+#[ffi_export]
+pub fn ffi_cfr_zero() -> repr_c::Box<CFr> {
+    CFr::from(Fr::from(0)).into()
+}
+
+#[ffi_export]
+pub fn ffi_cfr_one() -> repr_c::Box<CFr> {
+    CFr::from(Fr::from(1)).into()
+}
+
+#[ffi_export]
+pub fn ffi_cfr_to_bytes_le(cfr: &CFr) -> repr_c::Vec<u8> {
+    fr_to_bytes_le(&cfr.0).into()
+}
+
+#[ffi_export]
+pub fn ffi_cfr_to_bytes_be(cfr: &CFr) -> repr_c::Vec<u8> {
+    fr_to_bytes_be(&cfr.0).into()
+}
+
+#[ffi_export]
+pub fn ffi_bytes_le_to_cfr(bytes: &repr_c::Vec<u8>) -> CResult<repr_c::Box<CFr>, repr_c::String> {
+    match bytes_le_to_fr(bytes) {
+        Ok((cfr, _)) => CResult {
+            ok: Some(CFr(cfr).into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_bytes_be_to_cfr(bytes: &repr_c::Vec<u8>) -> CResult<repr_c::Box<CFr>, repr_c::String> {
+    match bytes_be_to_fr(bytes) {
+        Ok((cfr, _)) => CResult {
+            ok: Some(CFr(cfr).into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_uint_to_cfr(value: u32) -> repr_c::Box<CFr> {
+    CFr::from(Fr::from(value)).into()
+}
+
+#[ffi_export]
+pub fn ffi_cfr_debug(cfr: Option<&CFr>) -> repr_c::String {
+    match cfr {
+        Some(cfr) => format!("{:?}", cfr.0).into(),
+        None => "None".into(),
+    }
+}
+
+#[ffi_export]
+pub fn ffi_cfr_free(cfr: repr_c::Box<CFr>) {
+    drop(cfr);
+}
+
+// Vec<CFr>
+
+#[ffi_export]
+pub fn ffi_vec_cfr_new(capacity: usize) -> repr_c::Vec<CFr> {
+    Vec::with_capacity(capacity).into()
+}
+
+#[ffi_export]
+pub fn ffi_vec_cfr_from_cfr(cfr: &CFr) -> repr_c::Vec<CFr> {
+    vec![*cfr].into()
+}
+
+#[ffi_export]
+pub fn ffi_vec_cfr_push(v: &mut safer_ffi::Vec<CFr>, cfr: &CFr) {
+    let mut new: Vec<CFr> = std::mem::replace(v, Vec::new().into()).into();
+    if new.len() == new.capacity() {
+        new.reserve_exact(1);
+    }
+    new.push(*cfr);
+    *v = new.into();
+}
+
+#[ffi_export]
+pub fn ffi_vec_cfr_len(v: &repr_c::Vec<CFr>) -> usize {
+    v.len()
+}
+
+#[ffi_export]
+pub fn ffi_vec_cfr_get(v: &repr_c::Vec<CFr>, i: usize) -> Option<&CFr> {
+    v.get(i)
+}
+
+#[ffi_export]
+pub fn ffi_vec_cfr_to_bytes_le(vec: &repr_c::Vec<CFr>) -> repr_c::Vec<u8> {
+    let vec_fr: Vec<Fr> = vec.iter().map(|cfr| cfr.0).collect();
+    vec_fr_to_bytes_le(&vec_fr).into()
+}
+
+#[ffi_export]
+pub fn ffi_vec_cfr_to_bytes_be(vec: &repr_c::Vec<CFr>) -> repr_c::Vec<u8> {
+    let vec_fr: Vec<Fr> = vec.iter().map(|cfr| cfr.0).collect();
+    vec_fr_to_bytes_be(&vec_fr).into()
+}
+
+#[ffi_export]
+pub fn ffi_bytes_le_to_vec_cfr(
+    bytes: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Vec<CFr>, repr_c::String> {
+    match bytes_le_to_vec_fr(bytes) {
+        Ok((vec_fr, _)) => {
+            let vec_cfr: Vec<CFr> = vec_fr.into_iter().map(CFr).collect();
+            CResult {
+                ok: Some(vec_cfr.into()),
+                err: None,
+            }
+        }
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_bytes_be_to_vec_cfr(
+    bytes: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Vec<CFr>, repr_c::String> {
+    match bytes_be_to_vec_fr(bytes) {
+        Ok((vec_fr, _)) => {
+            let vec_cfr: Vec<CFr> = vec_fr.into_iter().map(CFr).collect();
+            CResult {
+                ok: Some(vec_cfr.into()),
+                err: None,
+            }
+        }
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_vec_cfr_debug(v: Option<&repr_c::Vec<CFr>>) -> repr_c::String {
+    match v {
+        Some(v) => {
+            let vec_fr: Vec<Fr> = v.iter().map(|cfr| cfr.0).collect();
+            format!("{:?}", vec_fr).into()
+        }
+        None => "None".into(),
+    }
+}
+
+#[ffi_export]
+pub fn ffi_vec_cfr_free(v: repr_c::Vec<CFr>) {
+    drop(v);
+}
+
+// Vec<u8>
+
+#[ffi_export]
+pub fn ffi_vec_u8_to_bytes_le(vec: &repr_c::Vec<u8>) -> repr_c::Vec<u8> {
+    vec_u8_to_bytes_le(vec).into()
+}
+
+#[ffi_export]
+pub fn ffi_vec_u8_to_bytes_be(vec: &repr_c::Vec<u8>) -> repr_c::Vec<u8> {
+    vec_u8_to_bytes_be(vec).into()
+}
+
+#[ffi_export]
+pub fn ffi_bytes_le_to_vec_u8(bytes: &repr_c::Vec<u8>) -> CResult<repr_c::Vec<u8>, repr_c::String> {
+    match bytes_le_to_vec_u8(bytes) {
+        Ok((vec, _)) => CResult {
+            ok: Some(vec.into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_bytes_be_to_vec_u8(bytes: &repr_c::Vec<u8>) -> CResult<repr_c::Vec<u8>, repr_c::String> {
+    match bytes_be_to_vec_u8(bytes) {
+        Ok((vec, _)) => CResult {
+            ok: Some(vec.into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(err.to_string().into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_vec_u8_debug(v: Option<&repr_c::Vec<u8>>) -> repr_c::String {
+    match v {
+        Some(v) => format!("{:x?}", v.deref()).into(),
+        None => "None".into(),
+    }
+}
+
+#[ffi_export]
+pub fn ffi_vec_u8_free(v: repr_c::Vec<u8>) {
+    drop(v);
+}
+
+// Utility APIs
+
+#[ffi_export]
+pub fn ffi_hash_to_field_le(input: &repr_c::Vec<u8>) -> CResult<repr_c::Box<CFr>, repr_c::String> {
+    match hash_to_field_le(input) {
+        Ok(hash_result) => CResult {
+            ok: Some(CFr::from(hash_result).into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_hash_to_field_be(input: &repr_c::Vec<u8>) -> CResult<repr_c::Box<CFr>, repr_c::String> {
+    match hash_to_field_be(input) {
+        Ok(hash_result) => CResult {
+            ok: Some(CFr::from(hash_result).into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_poseidon_hash_pair(a: &CFr, b: &CFr) -> CResult<repr_c::Box<CFr>, repr_c::String> {
+    match poseidon_hash(&[a.0, b.0]) {
+        Ok(hash_result) => CResult {
+            ok: Some(CFr::from(hash_result).into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_key_gen() -> CResult<repr_c::Vec<CFr>, repr_c::String> {
+    match keygen() {
+        Ok((identity_secret, id_commitment)) => CResult {
+            ok: Some(vec![CFr(*identity_secret), CFr(id_commitment)].into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_seeded_key_gen(seed: &repr_c::Vec<u8>) -> CResult<repr_c::Vec<CFr>, repr_c::String> {
+    match seeded_keygen(seed) {
+        Ok((identity_secret, id_commitment)) => CResult {
+            ok: Some(vec![CFr(identity_secret), CFr(id_commitment)].into()),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_extended_key_gen() -> CResult<repr_c::Vec<CFr>, repr_c::String> {
+    match extended_keygen() {
+        Ok((identity_trapdoor, identity_nullifier, identity_secret, id_commitment)) => CResult {
+            ok: Some(
+                vec![
+                    CFr(identity_trapdoor),
+                    CFr(identity_nullifier),
+                    CFr(identity_secret),
+                    CFr(id_commitment),
+                ]
+                .into(),
+            ),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_seeded_extended_key_gen(
+    seed: &repr_c::Vec<u8>,
+) -> CResult<repr_c::Vec<CFr>, repr_c::String> {
+    match extended_seeded_keygen(seed) {
+        Ok((identity_trapdoor, identity_nullifier, identity_secret, id_commitment)) => CResult {
+            ok: Some(
+                vec![
+                    CFr(identity_trapdoor),
+                    CFr(identity_nullifier),
+                    CFr(identity_secret),
+                    CFr(id_commitment),
+                ]
+                .into(),
+            ),
+            err: None,
+        },
+        Err(err) => CResult {
+            ok: None,
+            err: Some(format!("{:?}", err).into()),
+        },
+    }
+}
+
+#[ffi_export]
+pub fn ffi_c_string_free(s: repr_c::String) {
+    drop(s);
+}

rln/src/ffi/mod.rs

@@ -0,0 +1,10 @@
+#![cfg(not(target_arch = "wasm32"))]
+
+pub mod ffi_rln;
+pub mod ffi_tree;
+pub mod ffi_utils;
+
+#[cfg(feature = "headers")]
+pub fn generate_headers() -> std::io::Result<()> {
+    safer_ffi::headers::builder().to_file("rln.h")?.generate()
+}

rln/src/hashers.rs

@@ -1,13 +1,19 @@
-/// This crate instantiates the Poseidon hash algorithm.
-use crate::{circuit::Fr, utils::bytes_le_to_fr};
+// This crate instantiates the Poseidon hash algorithm.
+
 use once_cell::sync::Lazy;
 use tiny_keccak::{Hasher, Keccak};
-use utils::poseidon::Poseidon;
+use zerokit_utils::{error::HashError, poseidon::Poseidon};
+
+use crate::{
+    circuit::Fr,
+    error::UtilsError,
+    utils::{bytes_be_to_fr, bytes_le_to_fr},
+};
 
 /// These indexed constants hardcode the supported round parameters tuples (t, RF, RN, SKIP_MATRICES) for the Bn254 scalar field.
 /// SKIP_MATRICES is the index of the randomly generated secure MDS matrix.
 /// TODO: generate these parameters
-pub const ROUND_PARAMS: [(usize, usize, usize, usize); 8] = [
+const ROUND_PARAMS: [(usize, usize, usize, usize); 8] = [
     (2, 8, 56, 0),
     (3, 8, 57, 0),
     (4, 8, 56, 0),
@@ -21,10 +27,9 @@ pub const ROUND_PARAMS: [(usize, usize, usize, usize); 8] = [
 /// Poseidon Hash wrapper over above implementation.
 static POSEIDON: Lazy<Poseidon<Fr>> = Lazy::new(|| Poseidon::<Fr>::from(&ROUND_PARAMS));
 
-pub fn poseidon_hash(input: &[Fr]) -> Fr {
-    POSEIDON
-        .hash(input)
-        .expect("hash with fixed input size can't fail")
+pub fn poseidon_hash(input: &[Fr]) -> Result<Fr, HashError> {
+    let hash = POSEIDON.hash(input)?;
+    Ok(hash)
 }
 
 /// The zerokit RLN Merkle tree Hasher.
@@ -32,20 +37,21 @@ pub fn poseidon_hash(input: &[Fr]) -> Fr {
 pub struct PoseidonHash;
 
 /// The default Hasher trait used by Merkle tree implementation in utils.
-impl utils::merkle_tree::Hasher for PoseidonHash {
+impl zerokit_utils::merkle_tree::Hasher for PoseidonHash {
     type Fr = Fr;
+    type Error = HashError;
 
     fn default_leaf() -> Self::Fr {
         Self::Fr::from(0)
     }
 
-    fn hash(inputs: &[Self::Fr]) -> Self::Fr {
+    fn hash(inputs: &[Self::Fr]) -> Result<Self::Fr, Self::Error> {
         poseidon_hash(inputs)
     }
 }
 
 /// Hashes arbitrary signal to the underlying prime field.
-pub fn hash_to_field(signal: &[u8]) -> Fr {
+pub fn hash_to_field_le(signal: &[u8]) -> Result<Fr, UtilsError> {
     // We hash the input signal using Keccak256
     let mut hash = [0; 32];
     let mut hasher = Keccak::v256();
@@ -53,6 +59,24 @@ pub fn hash_to_field(signal: &[u8]) -> Fr {
     hasher.finalize(&mut hash);
 
     // We export the hash as a field element
-    let (el, _) = bytes_le_to_fr(hash.as_ref());
-    el
+    let (el, _) = bytes_le_to_fr(hash.as_ref())?;
+
+    Ok(el)
+}
+
+/// Hashes arbitrary signal to the underlying prime field.
+pub fn hash_to_field_be(signal: &[u8]) -> Result<Fr, UtilsError> {
+    // We hash the input signal using Keccak256
+    let mut hash = [0; 32];
+    let mut hasher = Keccak::v256();
+    hasher.update(signal);
+    hasher.finalize(&mut hash);
+
+    // Reverse the bytes to get big endian representation
+    hash.reverse();
+
+    // We export the hash as a field element
+    let (el, _) = bytes_be_to_fr(hash.as_ref())?;
+
+    Ok(el)
 }

rln/src/lib.rs

@@ -1,12 +1,31 @@
 pub mod circuit;
-#[cfg(not(target_arch = "wasm32"))]
+pub mod error;
 pub mod ffi;
 pub mod hashers;
-#[cfg(feature = "pmtree-ft")]
 pub mod pm_tree_adapter;
 pub mod poseidon_tree;
+pub mod prelude;
 pub mod protocol;
 pub mod public;
-#[cfg(test)]
-pub mod public_api_tests;
 pub mod utils;
+
+// Ensure that only one Merkle tree feature is enabled at a time
+#[cfg(any(
+    all(feature = "fullmerkletree", feature = "optimalmerkletree"),
+    all(feature = "fullmerkletree", feature = "pmtree-ft"),
+    all(feature = "optimalmerkletree", feature = "pmtree-ft"),
+))]
+compile_error!(
+    "Only one of `fullmerkletree`, `optimalmerkletree`, or `pmtree-ft` can be enabled at a time."
+);
+
+// Ensure that the `stateless` feature is not enabled with any Merkle tree features
+#[cfg(all(
+    feature = "stateless",
+    any(
+        feature = "fullmerkletree",
+        feature = "optimalmerkletree",
+        feature = "pmtree-ft"
+    )
+))]
+compile_error!("Cannot enable any Merkle tree features with stateless");

rln/src/pm_tree_adapter.rs

@@ -1,17 +1,24 @@
-use std::fmt::Debug;
-use std::path::PathBuf;
-use std::str::FromStr;
+#![cfg(feature = "pmtree-ft")]
+
+use std::{fmt::Debug, path::PathBuf, str::FromStr};
 
-use color_eyre::{Report, Result};
 use serde_json::Value;
+use tempfile::Builder;
+use zerokit_utils::{
+    error::{FromConfigError, ZerokitMerkleTreeError},
+    merkle_tree::{ZerokitMerkleProof, ZerokitMerkleTree},
+    pm_tree::{
+        pmtree,
+        pmtree::{tree::Key, Database, Hasher, PmtreeErrorKind},
+        Config, Mode, SledDB,
+    },
+};
 
-use utils::pmtree::tree::Key;
-use utils::pmtree::{Database, Hasher};
-use utils::*;
-
-use crate::circuit::Fr;
-use crate::hashers::{poseidon_hash, PoseidonHash};
-use crate::utils::{bytes_le_to_fr, fr_to_bytes_le};
+use crate::{
+    circuit::Fr,
+    hashers::{poseidon_hash, PoseidonHash},
+    utils::{bytes_le_to_fr, fr_to_bytes_le},
+};
 
 const METADATA_KEY: [u8; 8] = *b"metadata";
 
@@ -39,7 +46,8 @@ impl Hasher for PoseidonHash {
     }
 
     fn deserialize(value: pmtree::Value) -> Self::Fr {
-        let (fr, _) = bytes_le_to_fr(&value);
+        // TODO: allow to handle error properly in pmtree Hasher trait
+        let (fr, _) = bytes_le_to_fr(&value).expect("Fr deserialization must be valid");
         fr
     }
 
@@ -48,24 +56,114 @@ impl Hasher for PoseidonHash {
     }
 
     fn hash(inputs: &[Self::Fr]) -> Self::Fr {
-        poseidon_hash(inputs)
+        // TODO: allow to handle error properly in pmtree Hasher trait
+        poseidon_hash(inputs).expect("Poseidon hash must be valid")
     }
 }
 
-fn get_tmp_path() -> PathBuf {
-    std::env::temp_dir().join(format!("pmtree-{}", rand::random::<u64>()))
+fn default_tmp_path() -> Result<PathBuf, std::io::Error> {
+    Ok(Builder::new()
+        .prefix("pmtree-")
+        .tempfile()?
+        .into_temp_path()
+        .to_path_buf())
 }
 
-fn get_tmp() -> bool {
-    true
+const DEFAULT_TEMPORARY: bool = true;
+const DEFAULT_CACHE_CAPACITY: u64 = 1073741824; // 1 Gigabyte
+const DEFAULT_FLUSH_EVERY_MS: u64 = 500; // 500 Milliseconds
+const DEFAULT_MODE: Mode = Mode::HighThroughput;
+const DEFAULT_USE_COMPRESSION: bool = false;
+
+pub struct PmtreeConfigBuilder {
+    path: Option<PathBuf>,
+    temporary: bool,
+    cache_capacity: u64,
+    flush_every_ms: u64,
+    mode: Mode,
+    use_compression: bool,
+}
+
+impl Default for PmtreeConfigBuilder {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl PmtreeConfigBuilder {
+    pub fn new() -> Self {
+        PmtreeConfigBuilder {
+            path: None,
+            temporary: DEFAULT_TEMPORARY,
+            cache_capacity: DEFAULT_CACHE_CAPACITY,
+            flush_every_ms: DEFAULT_FLUSH_EVERY_MS,
+            mode: DEFAULT_MODE,
+            use_compression: DEFAULT_USE_COMPRESSION,
+        }
+    }
+
+    pub fn path<P: Into<PathBuf>>(mut self, path: P) -> Self {
+        self.path = Some(path.into());
+        self
+    }
+
+    pub fn temporary(mut self, temporary: bool) -> Self {
+        self.temporary = temporary;
+        self
+    }
+
+    pub fn cache_capacity(mut self, capacity: u64) -> Self {
+        self.cache_capacity = capacity;
+        self
+    }
+
+    pub fn flush_every_ms(mut self, ms: u64) -> Self {
+        self.flush_every_ms = ms;
+        self
+    }
+
+    pub fn mode(mut self, mode: Mode) -> Self {
+        self.mode = mode;
+        self
+    }
+
+    pub fn use_compression(mut self, compression: bool) -> Self {
+        self.use_compression = compression;
+        self
+    }
+
+    pub fn build(self) -> Result<PmtreeConfig, FromConfigError> {
+        let path = match (self.temporary, self.path) {
+            (true, None) => default_tmp_path()?,
+            (false, None) => return Err(FromConfigError::MissingPath),
+            (true, Some(path)) if path.exists() => return Err(FromConfigError::PathExists),
+            (_, Some(path)) => path,
+        };
+
+        let config = Config::new()
+            .temporary(self.temporary)
+            .path(path)
+            .cache_capacity(self.cache_capacity)
+            .flush_every_ms(Some(self.flush_every_ms))
+            .mode(self.mode)
+            .use_compression(self.use_compression);
+
+        Ok(PmtreeConfig(config))
+    }
 }
 
 pub struct PmtreeConfig(Config);
 
-impl FromStr for PmtreeConfig {
-    type Err = Report;
+impl PmtreeConfig {
+    pub fn builder() -> PmtreeConfigBuilder {
+        PmtreeConfigBuilder::new()
+    }
+}
 
-    fn from_str(s: &str) -> Result<Self> {
+impl FromStr for PmtreeConfig {
+    type Err = FromConfigError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
         let config: Value = serde_json::from_str(s)?;
 
         let path = config["path"].as_str();
@@ -80,21 +178,17 @@ impl FromStr for PmtreeConfig {
         };
         let use_compression = config["use_compression"].as_bool();
 
-        if temporary.is_some()
-            && path.is_some()
-            && temporary.unwrap()
-            && path.as_ref().unwrap().exists()
-        {
-            return Err(Report::msg(format!(
-                "Path {:?} already exists, cannot use temporary",
-                path.unwrap()
-            )));
+        if let (Some(true), Some(path)) = (temporary, path.as_ref()) {
+            if path.exists() {
+                return Err(FromConfigError::PathExists);
+            }
         }
 
+        let default_tmp_path = default_tmp_path()?;
         let config = Config::new()
-            .temporary(temporary.unwrap_or(get_tmp()))
-            .path(path.unwrap_or(get_tmp_path()))
-            .cache_capacity(cache_capacity.unwrap_or(1024 * 1024 * 1024))
+            .temporary(temporary.unwrap_or(DEFAULT_TEMPORARY))
+            .path(path.unwrap_or(default_tmp_path))
+            .cache_capacity(cache_capacity.unwrap_or(DEFAULT_CACHE_CAPACITY))
             .flush_every_ms(flush_every_ms)
             .mode(mode)
             .use_compression(use_compression.unwrap_or(false));
@@ -104,18 +198,12 @@ impl FromStr for PmtreeConfig {
 
 impl Default for PmtreeConfig {
     fn default() -> Self {
-        let tmp_path = get_tmp_path();
-        PmtreeConfig(
-            Config::new()
-                .temporary(true)
-                .path(tmp_path)
-                .cache_capacity(150_000)
-                .mode(Mode::HighThroughput)
-                .use_compression(false)
-                .flush_every_ms(Some(12_000)),
-        )
+        Self::builder()
+            .build()
+            .expect("Default PmtreeConfig must be valid")
     }
 }
+
 impl Debug for PmtreeConfig {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         self.0.fmt(f)
@@ -133,12 +221,16 @@ impl ZerokitMerkleTree for PmTree {
     type Hasher = PoseidonHash;
     type Config = PmtreeConfig;
 
-    fn default(depth: usize) -> Result<Self> {
+    fn default(depth: usize) -> Result<Self, ZerokitMerkleTreeError> {
         let default_config = PmtreeConfig::default();
         PmTree::new(depth, Self::Hasher::default_leaf(), default_config)
     }
 
-    fn new(depth: usize, _default_leaf: FrOf<Self::Hasher>, config: Self::Config) -> Result<Self> {
+    fn new(
+        depth: usize,
+        _default_leaf: FrOf<Self::Hasher>,
+        config: Self::Config,
+    ) -> Result<Self, ZerokitMerkleTreeError> {
         let tree_loaded = pmtree::MerkleTree::load(config.clone().0);
         let tree = match tree_loaded {
             Ok(tree) => tree,
@@ -168,14 +260,12 @@ impl ZerokitMerkleTree for PmTree {
         self.tree.root()
     }
 
-    fn compute_root(&mut self) -> Result<FrOf<Self::Hasher>> {
-        Ok(self.tree.root())
-    }
-
-    fn set(&mut self, index: usize, leaf: FrOf<Self::Hasher>) -> Result<()> {
-        self.tree
-            .set(index, leaf)
-            .map_err(|e| Report::msg(e.to_string()))?;
+    fn set(
+        &mut self,
+        index: usize,
+        leaf: FrOf<Self::Hasher>,
+    ) -> Result<(), ZerokitMerkleTreeError> {
+        self.tree.set(index, leaf)?;
         self.cached_leaves_indices[index] = 1;
         Ok(())
     }
@@ -184,38 +274,41 @@ impl ZerokitMerkleTree for PmTree {
         &mut self,
         start: usize,
         values: I,
-    ) -> Result<()> {
+    ) -> Result<(), ZerokitMerkleTreeError> {
         let v = values.into_iter().collect::<Vec<_>>();
-        self.tree
-            .set_range(start, v.clone().into_iter())
-            .map_err(|e| Report::msg(e.to_string()))?;
+        self.tree.set_range(start, v.clone().into_iter())?;
         for i in start..v.len() {
             self.cached_leaves_indices[i] = 1
         }
         Ok(())
     }
 
-    fn get(&self, index: usize) -> Result<FrOf<Self::Hasher>> {
-        self.tree.get(index).map_err(|e| Report::msg(e.to_string()))
+    fn get(&self, index: usize) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError> {
+        self.tree
+            .get(index)
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
     }
 
-    fn get_subtree_root(&self, n: usize, index: usize) -> Result<FrOf<Self::Hasher>> {
+    fn get_subtree_root(
+        &self,
+        n: usize,
+        index: usize,
+    ) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError> {
         if n > self.depth() {
-            return Err(Report::msg("level exceeds depth size"));
+            return Err(ZerokitMerkleTreeError::InvalidLevel);
         }
         if index >= self.capacity() {
-            return Err(Report::msg("index exceeds set size"));
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
         }
         if n == 0 {
             Ok(self.root())
         } else if n == self.depth() {
             self.get(index)
         } else {
-            let node = self
-                .tree
-                .get_elem(Key::new(n, index >> (self.depth() - n)))
-                .unwrap();
-            Ok(node)
+            match self.tree.get_elem(Key::new(n, index >> (self.depth() - n))) {
+                Ok(value) => Ok(value),
+                Err(_) => Err(ZerokitMerkleTreeError::InvalidSubTreeIndex),
+            }
         }
     }
 
@@ -235,70 +328,86 @@ impl ZerokitMerkleTree for PmTree {
         start: usize,
         leaves: I,
         indices: J,
-    ) -> Result<()> {
+    ) -> Result<(), ZerokitMerkleTreeError> {
         let leaves = leaves.into_iter().collect::<Vec<_>>();
         let mut indices = indices.into_iter().collect::<Vec<_>>();
         indices.sort();
 
         match (leaves.len(), indices.len()) {
-            (0, 0) => Err(Report::msg("no leaves or indices to be removed")),
+            (0, 0) => Err(ZerokitMerkleTreeError::InvalidLeaf),
             (1, 0) => self.set(start, leaves[0]),
             (0, 1) => self.delete(indices[0]),
             (_, 0) => self.set_range(start, leaves.into_iter()),
-            (0, _) => self.remove_indices(&indices),
-            (_, _) => self.remove_indices_and_set_leaves(start, leaves, &indices),
+            (0, _) => self
+                .remove_indices(&indices)
+                .map_err(ZerokitMerkleTreeError::PmtreeErrorKind),
+            (_, _) => self
+                .remove_indices_and_set_leaves(start, leaves, &indices)
+                .map_err(ZerokitMerkleTreeError::PmtreeErrorKind),
         }
     }
 
-    fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<()> {
+    fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<(), ZerokitMerkleTreeError> {
         self.tree
             .update_next(leaf)
-            .map_err(|e| Report::msg(e.to_string()))
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
     }
 
-    fn delete(&mut self, index: usize) -> Result<()> {
+    /// Delete a leaf in the merkle tree given its index
+    ///
+    /// Deleting a leaf is done by resetting it to its default value. Note that the next_index field
+    /// will not be changed (== previously used index cannot be reused - this to avoid replay
+    /// attacks or unexpected and very hard to tackle issues)
+    fn delete(&mut self, index: usize) -> Result<(), ZerokitMerkleTreeError> {
         self.tree
             .delete(index)
-            .map_err(|e| Report::msg(e.to_string()))?;
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)?;
         self.cached_leaves_indices[index] = 0;
         Ok(())
     }
 
-    fn proof(&self, index: usize) -> Result<Self::Proof> {
+    fn proof(&self, index: usize) -> Result<Self::Proof, ZerokitMerkleTreeError> {
         let proof = self.tree.proof(index)?;
         Ok(PmTreeProof { proof })
     }
 
-    fn verify(&self, leaf: &FrOf<Self::Hasher>, witness: &Self::Proof) -> Result<bool> {
-        if self.tree.verify(leaf, &witness.proof) {
+    fn verify(
+        &self,
+        leaf: &FrOf<Self::Hasher>,
+        merkle_proof: &Self::Proof,
+    ) -> Result<bool, ZerokitMerkleTreeError> {
+        if self.tree.verify(leaf, &merkle_proof.proof) {
             Ok(true)
         } else {
-            Err(Report::msg("verify failed"))
+            Err(ZerokitMerkleTreeError::InvalidMerkleProof)
         }
     }
 
-    fn set_metadata(&mut self, metadata: &[u8]) -> Result<()> {
-        self.tree.db.put(METADATA_KEY, metadata.to_vec())?;
+    fn set_metadata(&mut self, metadata: &[u8]) -> Result<(), ZerokitMerkleTreeError> {
+        self.tree
+            .db
+            .put(METADATA_KEY, metadata.to_vec())
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)?;
         self.metadata = metadata.to_vec();
         Ok(())
     }
 
-    fn metadata(&self) -> Result<Vec<u8>> {
+    fn metadata(&self) -> Result<Vec<u8>, ZerokitMerkleTreeError> {
         if !self.metadata.is_empty() {
             return Ok(self.metadata.clone());
         }
         // if empty, try searching the db
         let data = self.tree.db.get(METADATA_KEY)?;
 
-        if data.is_none() {
-            // send empty Metadata
-            return Ok(Vec::new());
-        }
-        Ok(data.unwrap())
+        // Return empty metadata if not found, otherwise return the data
+        Ok(data.unwrap_or_default())
     }
 
-    fn close_db_connection(&mut self) -> Result<()> {
-        self.tree.db.close().map_err(|e| Report::msg(e.to_string()))
+    fn close_db_connection(&mut self) -> Result<(), ZerokitMerkleTreeError> {
+        self.tree
+            .db
+            .close()
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
     }
 }
 
@@ -306,15 +415,18 @@ type PmTreeHasher = <PmTree as ZerokitMerkleTree>::Hasher;
 type FrOfPmTreeHasher = FrOf<PmTreeHasher>;
 
 impl PmTree {
-    fn remove_indices(&mut self, indices: &[usize]) -> Result<()> {
+    fn remove_indices(&mut self, indices: &[usize]) -> Result<(), PmtreeErrorKind> {
+        if indices.is_empty() {
+            return Err(PmtreeErrorKind::TreeError(
+                pmtree::TreeErrorKind::InvalidKey,
+            ));
+        }
         let start = indices[0];
-        let end = indices.last().unwrap() + 1;
+        let end = indices[indices.len() - 1] + 1;
 
         let new_leaves = (start..end).map(|_| PmTreeHasher::default_leaf());
 
-        self.tree
-            .set_range(start, new_leaves)
-            .map_err(|e| Report::msg(e.to_string()))?;
+        self.tree.set_range(start, new_leaves)?;
 
         for i in start..end {
             self.cached_leaves_indices[i] = 0
@@ -327,8 +439,13 @@ impl PmTree {
         start: usize,
         leaves: Vec<FrOfPmTreeHasher>,
         indices: &[usize],
-    ) -> Result<()> {
-        let min_index = *indices.first().unwrap();
+    ) -> Result<(), PmtreeErrorKind> {
+        if indices.is_empty() {
+            return Err(PmtreeErrorKind::TreeError(
+                pmtree::TreeErrorKind::InvalidKey,
+            ));
+        }
+        let min_index = indices[0];
         let max_index = start + leaves.len();
 
         let mut set_values = vec![PmTreeHasher::default_leaf(); max_index - min_index];
@@ -344,9 +461,7 @@ impl PmTree {
             set_values[start - min_index + i] = leaf;
         }
 
-        self.tree
-            .set_range(start, set_values)
-            .map_err(|e| Report::msg(e.to_string()))?;
+        self.tree.set_range(start, set_values)?;
 
         for i in indices {
             self.cached_leaves_indices[*i] = 0;
@@ -378,7 +493,40 @@ impl ZerokitMerkleProof for PmTreeProof {
     fn get_path_index(&self) -> Vec<Self::Index> {
         self.proof.get_path_index()
     }
-    fn compute_root_from(&self, leaf: &FrOf<Self::Hasher>) -> FrOf<Self::Hasher> {
-        self.proof.compute_root_from(leaf)
+
+    fn compute_root_from(
+        &self,
+        leaf: &FrOf<Self::Hasher>,
+    ) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError> {
+        Ok(self.proof.compute_root_from(leaf))
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_pmtree_json_config() {
+        let json = r#"
+        {
+            "path": "pmtree-123456",
+            "temporary": false,
+            "cache_capacity": 1073741824,
+            "flush_every_ms": 500,
+            "mode": "HighThroughput",
+            "use_compression": false
+        }"#;
+
+        let _: PmtreeConfig = json.parse().unwrap();
+
+        let _ = PmtreeConfig::builder()
+            .path(default_tmp_path().unwrap())
+            .temporary(DEFAULT_TEMPORARY)
+            .cache_capacity(DEFAULT_CACHE_CAPACITY)
+            .mode(DEFAULT_MODE)
+            .use_compression(DEFAULT_USE_COMPRESSION)
+            .build()
+            .unwrap();
     }
 }

rln/src/poseidon_tree.rs

@@ -1,30 +1,32 @@
 // This crate defines the RLN module default Merkle tree implementation and its Hasher
+// Implementation inspired by https://github.com/worldcoin/semaphore-rs/blob/d462a4372f1fd9c27610f2acfe4841fab1d396aa/src/poseidon_tree.rs
 
-// Implementation inspired by https://github.com/worldcoin/semaphore-rs/blob/d462a4372f1fd9c27610f2acfe4841fab1d396aa/src/poseidon_tree.rs (no differences)
+#![cfg(not(feature = "stateless"))]
 
 use cfg_if::cfg_if;
 
-cfg_if! {
-    if #[cfg(feature = "pmtree-ft")] {
-        use crate::pm_tree_adapter::*;
-    } else {
-        use crate::hashers::{PoseidonHash};
-        use utils::merkle_tree::*;
-    }
-}
-
-// The zerokit RLN default Merkle tree implementation is the OptimalMerkleTree.
-// To switch to FullMerkleTree implementation, it is enough to enable the fullmerkletree feature
+// The zerokit RLN default Merkle tree implementation is the PMTree from the vacp2p_pmtree crate
+// To switch to FullMerkleTree or OptimalMerkleTree, enable the corresponding feature in the Cargo.toml file
 
 cfg_if! {
     if #[cfg(feature = "fullmerkletree")] {
+        use zerokit_utils::merkle_tree::{FullMerkleTree, FullMerkleProof};
+        use crate::hashers::PoseidonHash;
+
         pub type PoseidonTree = FullMerkleTree<PoseidonHash>;
         pub type MerkleProof = FullMerkleProof<PoseidonHash>;
+    } else if #[cfg(feature = "optimalmerkletree")] {
+        use zerokit_utils::merkle_tree::{OptimalMerkleTree, OptimalMerkleProof};
+        use crate::hashers::PoseidonHash;
+
+        pub type PoseidonTree = OptimalMerkleTree<PoseidonHash>;
+        pub type MerkleProof = OptimalMerkleProof<PoseidonHash>;
     } else if #[cfg(feature = "pmtree-ft")] {
+        use crate::pm_tree_adapter::{PmTree, PmTreeProof};
+
         pub type PoseidonTree = PmTree;
         pub type MerkleProof = PmTreeProof;
     } else {
-        pub type PoseidonTree = OptimalMerkleTree<PoseidonHash>;
-        pub type MerkleProof = OptimalMerkleProof<PoseidonHash>;
+        compile_error!("One of the features `fullmerkletree`, `optimalmerkletree`, or `pmtree-ft` must be enabled.");
     }
 }

rln/src/prelude.rs

@@ -0,0 +1,37 @@
+// This module re-exports the most commonly used types and functions from the RLN library
+
+#[cfg(not(target_arch = "wasm32"))]
+pub use crate::circuit::{graph_from_folder, zkey_from_folder};
+#[cfg(feature = "pmtree-ft")]
+pub use crate::pm_tree_adapter::{FrOf, PmTree, PmTreeProof, PmtreeConfig, PmtreeConfigBuilder};
+#[cfg(not(feature = "stateless"))]
+pub use crate::poseidon_tree::{MerkleProof, PoseidonTree};
+#[cfg(not(feature = "stateless"))]
+pub use crate::protocol::compute_tree_root;
+#[cfg(not(target_arch = "wasm32"))]
+pub use crate::protocol::{generate_zk_proof, verify_zk_proof};
+pub use crate::{
+    circuit::{
+        zkey_from_raw, Curve, Fq, Fq2, Fr, G1Affine, G1Projective, G2Affine, G2Projective, Proof,
+        VerifyingKey, Zkey, COMPRESS_PROOF_SIZE, DEFAULT_TREE_DEPTH,
+    },
+    error::{ProtocolError, RLNError, UtilsError, VerifyError},
+    hashers::{hash_to_field_be, hash_to_field_le, poseidon_hash, PoseidonHash},
+    protocol::{
+        bytes_be_to_rln_proof, bytes_be_to_rln_proof_values, bytes_be_to_rln_witness,
+        bytes_le_to_rln_proof, bytes_le_to_rln_proof_values, bytes_le_to_rln_witness,
+        extended_keygen, extended_seeded_keygen, generate_zk_proof_with_witness, keygen,
+        proof_values_from_witness, recover_id_secret, rln_proof_to_bytes_be, rln_proof_to_bytes_le,
+        rln_proof_values_to_bytes_be, rln_proof_values_to_bytes_le, rln_witness_to_bigint_json,
+        rln_witness_to_bytes_be, rln_witness_to_bytes_le, seeded_keygen, RLNProof, RLNProofValues,
+        RLNWitnessInput,
+    },
+    public::RLN,
+    utils::{
+        bytes_be_to_fr, bytes_be_to_vec_fr, bytes_be_to_vec_u8, bytes_be_to_vec_usize,
+        bytes_le_to_fr, bytes_le_to_vec_fr, bytes_le_to_vec_u8, bytes_le_to_vec_usize,
+        fr_to_bytes_be, fr_to_bytes_le, normalize_usize_be, normalize_usize_le, str_to_fr,
+        to_bigint, vec_fr_to_bytes_be, vec_fr_to_bytes_le, vec_u8_to_bytes_be, vec_u8_to_bytes_le,
+        IdSecret, FR_BYTE_SIZE,
+    },
+};

rln/src/protocol.rs

@@ -1,795 +0,0 @@
-// This crate collects all the underlying primitives used to implement RLN
-
-use ark_bn254::Fr;
-use ark_groth16::{prepare_verifying_key, Groth16, Proof as ArkProof, ProvingKey, VerifyingKey};
-use ark_relations::r1cs::{ConstraintMatrices, SynthesisError};
-use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
-use ark_std::{rand::thread_rng, UniformRand};
-use color_eyre::{Report, Result};
-use num_bigint::BigInt;
-use rand::{Rng, SeedableRng};
-use rand_chacha::ChaCha20Rng;
-use serde::{Deserialize, Serialize};
-#[cfg(test)]
-use std::time::Instant;
-use thiserror::Error;
-use tiny_keccak::{Hasher as _, Keccak};
-
-use crate::circuit::{calculate_rln_witness, qap::CircomReduction, Curve};
-use crate::hashers::{hash_to_field, poseidon_hash};
-use crate::poseidon_tree::*;
-use crate::public::RLN_IDENTIFIER;
-use crate::utils::*;
-use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
-
-///////////////////////////////////////////////////////
-// RLN Witness data structure and utility functions
-///////////////////////////////////////////////////////
-
-#[derive(Debug, PartialEq, Serialize, Deserialize)]
-pub struct RLNWitnessInput {
-    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
-    identity_secret: Fr,
-    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
-    user_message_limit: Fr,
-    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
-    message_id: Fr,
-    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
-    path_elements: Vec<Fr>,
-    identity_path_index: Vec<u8>,
-    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
-    x: Fr,
-    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
-    external_nullifier: Fr,
-}
-
-#[derive(Debug, PartialEq)]
-pub struct RLNProofValues {
-    // Public outputs:
-    pub y: Fr,
-    pub nullifier: Fr,
-    pub root: Fr,
-    // Public Inputs:
-    pub x: Fr,
-    pub external_nullifier: Fr,
-}
-
-pub fn serialize_field_element(element: Fr) -> Vec<u8> {
-    fr_to_bytes_le(&element)
-}
-
-pub fn deserialize_field_element(serialized: Vec<u8>) -> Fr {
-    let (element, _) = bytes_le_to_fr(&serialized);
-
-    element
-}
-
-pub fn deserialize_identity_pair(serialized: Vec<u8>) -> (Fr, Fr) {
-    let (identity_secret_hash, read) = bytes_le_to_fr(&serialized);
-    let (id_commitment, _) = bytes_le_to_fr(&serialized[read..]);
-
-    (identity_secret_hash, id_commitment)
-}
-
-pub fn deserialize_identity_tuple(serialized: Vec<u8>) -> (Fr, Fr, Fr, Fr) {
-    let mut all_read = 0;
-
-    let (identity_trapdoor, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (identity_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (identity_secret_hash, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (identity_commitment, _) = bytes_le_to_fr(&serialized[all_read..]);
-
-    (
-        identity_trapdoor,
-        identity_nullifier,
-        identity_secret_hash,
-        identity_commitment,
-    )
-}
-
-/// Serializes witness
-///
-/// # Errors
-///
-/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
-/// input data is [ identity_secret<32> | user_message_limit<32> | message_id<32> | path_elements[<32>] | identity_path_index<8> | x<32> | external_nullifier<32> ]
-pub fn serialize_witness(rln_witness: &RLNWitnessInput) -> Result<Vec<u8>> {
-    // Check if message_id is within user_message_limit
-    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
-
-    // Calculate capacity for Vec:
-    // - 5 fixed field elements: identity_secret, user_message_limit, message_id, x, external_nullifier
-    // - variable number of path elements
-    // - identity_path_index (variable size)
-    let mut serialized: Vec<u8> = Vec::with_capacity(
-        fr_byte_size() * (5 + rln_witness.path_elements.len())
-            + rln_witness.identity_path_index.len(),
-    );
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.identity_secret));
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.user_message_limit));
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.message_id));
-    serialized.extend_from_slice(&vec_fr_to_bytes_le(&rln_witness.path_elements)?);
-    serialized.extend_from_slice(&vec_u8_to_bytes_le(&rln_witness.identity_path_index)?);
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.x));
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.external_nullifier));
-
-    Ok(serialized)
-}
-
-/// Deserializes witness
-///
-/// # Errors
-///
-/// Returns an error if `message_id` is not within `user_message_limit`.
-pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)> {
-    let mut all_read: usize = 0;
-
-    let (identity_secret, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (user_message_limit, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (message_id, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    message_id_range_check(&message_id, &user_message_limit)?;
-
-    let (path_elements, read) = bytes_le_to_vec_fr(&serialized[all_read..])?;
-    all_read += read;
-
-    let (identity_path_index, read) = bytes_le_to_vec_u8(&serialized[all_read..])?;
-    all_read += read;
-
-    let (x, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    if serialized.len() != all_read {
-        return Err(Report::msg("serialized length is not equal to all_read"));
-    }
-
-    Ok((
-        RLNWitnessInput {
-            identity_secret,
-            path_elements,
-            identity_path_index,
-            x,
-            external_nullifier,
-            user_message_limit,
-            message_id,
-        },
-        all_read,
-    ))
-}
-
-// This function deserializes input for kilic's rln generate_proof public API
-// https://github.com/kilic/rln/blob/7ac74183f8b69b399e3bc96c1ae8ab61c026dc43/src/public.rs#L148
-// input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
-// return value is a rln witness populated according to this information
-pub fn proof_inputs_to_rln_witness(
-    tree: &mut PoseidonTree,
-    serialized: &[u8],
-) -> Result<(RLNWitnessInput, usize)> {
-    let mut all_read: usize = 0;
-
-    let (identity_secret, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let id_index = usize::try_from(u64::from_le_bytes(
-        serialized[all_read..all_read + 8].try_into()?,
-    ))?;
-    all_read += 8;
-
-    let (user_message_limit, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (message_id, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let signal_len = usize::try_from(u64::from_le_bytes(
-        serialized[all_read..all_read + 8].try_into()?,
-    ))?;
-    all_read += 8;
-
-    let signal: Vec<u8> = serialized[all_read..all_read + signal_len].to_vec();
-
-    let merkle_proof = tree.proof(id_index).expect("proof should exist");
-    let path_elements = merkle_proof.get_path_elements();
-    let identity_path_index = merkle_proof.get_path_index();
-
-    let x = hash_to_field(&signal);
-
-    Ok((
-        RLNWitnessInput {
-            identity_secret,
-            path_elements,
-            identity_path_index,
-            user_message_limit,
-            message_id,
-            x,
-            external_nullifier,
-        },
-        all_read,
-    ))
-}
-
-/// Creates [`RLNWitnessInput`] from it's fields.
-///
-/// # Errors
-///
-/// Returns an error if `message_id` is not within `user_message_limit`.
-pub fn rln_witness_from_values(
-    identity_secret: Fr,
-    merkle_proof: &MerkleProof,
-    x: Fr,
-    external_nullifier: Fr,
-    user_message_limit: Fr,
-    message_id: Fr,
-) -> Result<RLNWitnessInput> {
-    message_id_range_check(&message_id, &user_message_limit)?;
-
-    let path_elements = merkle_proof.get_path_elements();
-    let identity_path_index = merkle_proof.get_path_index();
-
-    Ok(RLNWitnessInput {
-        identity_secret,
-        path_elements,
-        identity_path_index,
-        x,
-        external_nullifier,
-        user_message_limit,
-        message_id,
-    })
-}
-
-pub fn random_rln_witness(tree_height: usize) -> RLNWitnessInput {
-    let mut rng = thread_rng();
-
-    let identity_secret = hash_to_field(&rng.gen::<[u8; 32]>());
-    let x = hash_to_field(&rng.gen::<[u8; 32]>());
-    let epoch = hash_to_field(&rng.gen::<[u8; 32]>());
-    let rln_identifier = hash_to_field(RLN_IDENTIFIER); //hash_to_field(&rng.gen::<[u8; 32]>());
-
-    let mut path_elements: Vec<Fr> = Vec::new();
-    let mut identity_path_index: Vec<u8> = Vec::new();
-
-    for _ in 0..tree_height {
-        path_elements.push(hash_to_field(&rng.gen::<[u8; 32]>()));
-        identity_path_index.push(rng.gen_range(0..2) as u8);
-    }
-
-    let user_message_limit = Fr::from(100);
-    let message_id = Fr::from(1);
-
-    RLNWitnessInput {
-        identity_secret,
-        path_elements,
-        identity_path_index,
-        x,
-        external_nullifier: poseidon_hash(&[epoch, rln_identifier]),
-        user_message_limit,
-        message_id,
-    }
-}
-
-pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> Result<RLNProofValues> {
-    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
-
-    // y share
-    let a_0 = rln_witness.identity_secret;
-    let a_1 = poseidon_hash(&[a_0, rln_witness.external_nullifier, rln_witness.message_id]);
-    let y = a_0 + rln_witness.x * a_1;
-
-    // Nullifier
-    let nullifier = poseidon_hash(&[a_1]);
-
-    // Merkle tree root computations
-    let root = compute_tree_root(
-        &rln_witness.identity_secret,
-        &rln_witness.user_message_limit,
-        &rln_witness.path_elements,
-        &rln_witness.identity_path_index,
-    );
-
-    Ok(RLNProofValues {
-        y,
-        nullifier,
-        root,
-        x: rln_witness.x,
-        external_nullifier: rln_witness.external_nullifier,
-    })
-}
-
-/// input_data is [ root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-pub fn serialize_proof_values(rln_proof_values: &RLNProofValues) -> Vec<u8> {
-    // Calculate capacity for Vec:
-    // 5 field elements: root, external_nullifier, x, y, nullifier
-    let mut serialized = Vec::with_capacity(fr_byte_size() * 5);
-
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.root));
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.external_nullifier));
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.x));
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.y));
-    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.nullifier));
-
-    serialized
-}
-
-// Note: don't forget to skip the 128 bytes ZK proof, if serialized contains it.
-// This proc deserialzies only proof _values_, i.e. circuit outputs, not the zk proof.
-pub fn deserialize_proof_values(serialized: &[u8]) -> (RLNProofValues, usize) {
-    let mut all_read: usize = 0;
-
-    let (root, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (x, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (y, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    let (nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    (
-        RLNProofValues {
-            y,
-            nullifier,
-            root,
-            x,
-            external_nullifier,
-        },
-        all_read,
-    )
-}
-
-// input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
-pub fn prepare_prove_input(
-    identity_secret: Fr,
-    id_index: usize,
-    user_message_limit: Fr,
-    message_id: Fr,
-    external_nullifier: Fr,
-    signal: &[u8],
-) -> Vec<u8> {
-    // Calculate capacity for Vec:
-    // - 4 field elements: identity_secret, user_message_limit, message_id, external_nullifier
-    // - 16 bytes for two normalized usize values (id_index<8> + signal_len<8>)
-    // - variable length signal data
-    let mut serialized = Vec::with_capacity(fr_byte_size() * 4 + 16 + signal.len()); // length of 4 fr elements + 16 bytes (id_index + len) + signal length
-
-    serialized.extend_from_slice(&fr_to_bytes_le(&identity_secret));
-    serialized.extend_from_slice(&normalize_usize(id_index));
-    serialized.extend_from_slice(&fr_to_bytes_le(&user_message_limit));
-    serialized.extend_from_slice(&fr_to_bytes_le(&message_id));
-    serialized.extend_from_slice(&fr_to_bytes_le(&external_nullifier));
-    serialized.extend_from_slice(&normalize_usize(signal.len()));
-    serialized.extend_from_slice(signal);
-
-    serialized
-}
-
-// input_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
-pub fn prepare_verify_input(proof_data: Vec<u8>, signal: &[u8]) -> Vec<u8> {
-    // Calculate capacity for Vec:
-    // - proof_data contains the proof and proof values (proof<128> + root<32> + external_nullifier<32> + x<32> + y<32> + nullifier<32>)
-    // - 8 bytes for normalized signal length value (signal_len<8>)
-    // - variable length signal data
-    let mut serialized = Vec::with_capacity(proof_data.len() + 8 + signal.len());
-
-    serialized.extend(proof_data);
-    serialized.extend_from_slice(&normalize_usize(signal.len()));
-    serialized.extend_from_slice(signal);
-
-    serialized
-}
-
-///////////////////////////////////////////////////////
-// Merkle tree utility functions
-///////////////////////////////////////////////////////
-
-pub fn compute_tree_root(
-    identity_secret: &Fr,
-    user_message_limit: &Fr,
-    path_elements: &[Fr],
-    identity_path_index: &[u8],
-) -> Fr {
-    let id_commitment = poseidon_hash(&[*identity_secret]);
-    let mut root = poseidon_hash(&[id_commitment, *user_message_limit]);
-
-    for i in 0..identity_path_index.len() {
-        if identity_path_index[i] == 0 {
-            root = poseidon_hash(&[root, path_elements[i]]);
-        } else {
-            root = poseidon_hash(&[path_elements[i], root]);
-        }
-    }
-
-    root
-}
-
-///////////////////////////////////////////////////////
-// Protocol utility functions
-///////////////////////////////////////////////////////
-
-// Generates a tuple (identity_secret_hash, id_commitment) where
-// identity_secret_hash is random and id_commitment = PoseidonHash(identity_secret_hash)
-// RNG is instantiated using thread_rng()
-pub fn keygen() -> (Fr, Fr) {
-    let mut rng = thread_rng();
-    let identity_secret_hash = Fr::rand(&mut rng);
-    let id_commitment = poseidon_hash(&[identity_secret_hash]);
-    (identity_secret_hash, id_commitment)
-}
-
-// Generates a tuple (identity_trapdoor, identity_nullifier, identity_secret_hash, id_commitment) where
-// identity_trapdoor and identity_nullifier are random,
-// identity_secret_hash = PoseidonHash(identity_trapdoor, identity_nullifier),
-// id_commitment = PoseidonHash(identity_secret_hash),
-// RNG is instantiated using thread_rng()
-// Generated credentials are compatible with Semaphore credentials
-pub fn extended_keygen() -> (Fr, Fr, Fr, Fr) {
-    let mut rng = thread_rng();
-    let identity_trapdoor = Fr::rand(&mut rng);
-    let identity_nullifier = Fr::rand(&mut rng);
-    let identity_secret_hash = poseidon_hash(&[identity_trapdoor, identity_nullifier]);
-    let id_commitment = poseidon_hash(&[identity_secret_hash]);
-    (
-        identity_trapdoor,
-        identity_nullifier,
-        identity_secret_hash,
-        id_commitment,
-    )
-}
-
-// Generates a tuple (identity_secret_hash, id_commitment) where
-// identity_secret_hash is random and id_commitment = PoseidonHash(identity_secret_hash)
-// RNG is instantiated using 20 rounds of ChaCha seeded with the hash of the input
-pub fn seeded_keygen(signal: &[u8]) -> (Fr, Fr) {
-    // ChaCha20 requires a seed of exactly 32 bytes.
-    // We first hash the input seed signal to a 32 bytes array and pass this as seed to ChaCha20
-    let mut seed = [0; 32];
-    let mut hasher = Keccak::v256();
-    hasher.update(signal);
-    hasher.finalize(&mut seed);
-
-    let mut rng = ChaCha20Rng::from_seed(seed);
-    let identity_secret_hash = Fr::rand(&mut rng);
-    let id_commitment = poseidon_hash(&[identity_secret_hash]);
-    (identity_secret_hash, id_commitment)
-}
-
-// Generates a tuple (identity_trapdoor, identity_nullifier, identity_secret_hash, id_commitment) where
-// identity_trapdoor and identity_nullifier are random,
-// identity_secret_hash = PoseidonHash(identity_trapdoor, identity_nullifier),
-// id_commitment = PoseidonHash(identity_secret_hash),
-// RNG is instantiated using 20 rounds of ChaCha seeded with the hash of the input
-// Generated credentials are compatible with Semaphore credentials
-pub fn extended_seeded_keygen(signal: &[u8]) -> (Fr, Fr, Fr, Fr) {
-    // ChaCha20 requires a seed of exactly 32 bytes.
-    // We first hash the input seed signal to a 32 bytes array and pass this as seed to ChaCha20
-    let mut seed = [0; 32];
-    let mut hasher = Keccak::v256();
-    hasher.update(signal);
-    hasher.finalize(&mut seed);
-
-    let mut rng = ChaCha20Rng::from_seed(seed);
-    let identity_trapdoor = Fr::rand(&mut rng);
-    let identity_nullifier = Fr::rand(&mut rng);
-    let identity_secret_hash = poseidon_hash(&[identity_trapdoor, identity_nullifier]);
-    let id_commitment = poseidon_hash(&[identity_secret_hash]);
-    (
-        identity_trapdoor,
-        identity_nullifier,
-        identity_secret_hash,
-        id_commitment,
-    )
-}
-
-pub fn compute_id_secret(share1: (Fr, Fr), share2: (Fr, Fr)) -> Result<Fr, String> {
-    // Assuming a0 is the identity secret and a1 = poseidonHash([a0, external_nullifier]),
-    // a (x,y) share satisfies the following relation
-    // y = a_0 + x * a_1
-    let (x1, y1) = share1;
-    let (x2, y2) = share2;
-
-    // If the two input shares were computed for the same external_nullifier and identity secret, we can recover the latter
-    // y1 = a_0 + x1 * a_1
-    // y2 = a_0 + x2 * a_1
-    let a_1 = (y1 - y2) / (x1 - x2);
-    let a_0 = y1 - x1 * a_1;
-
-    // If shares come from the same polynomial, a0 is correctly recovered and a1 = poseidonHash([a0, external_nullifier])
-    Ok(a_0)
-}
-
-///////////////////////////////////////////////////////
-// zkSNARK utility functions
-///////////////////////////////////////////////////////
-
-#[derive(Error, Debug)]
-pub enum ProofError {
-    #[error("Error reading circuit key: {0}")]
-    CircuitKeyError(#[from] Report),
-    #[error("Error producing witness: {0}")]
-    WitnessError(Report),
-    #[error("Error producing proof: {0}")]
-    SynthesisError(#[from] SynthesisError),
-}
-
-fn calculate_witness_element<E: ark_ec::pairing::Pairing>(
-    witness: Vec<BigInt>,
-) -> Result<Vec<E::ScalarField>> {
-    use ark_ff::PrimeField;
-    let modulus = <E::ScalarField as PrimeField>::MODULUS;
-
-    // convert it to field elements
-    use num_traits::Signed;
-    let mut witness_vec = vec![];
-    for w in witness.into_iter() {
-        let w = if w.sign() == num_bigint::Sign::Minus {
-            // Need to negate the witness element if negative
-            modulus.into()
-                - w.abs()
-                    .to_biguint()
-                    .ok_or(Report::msg("not a biguint value"))?
-        } else {
-            w.to_biguint().ok_or(Report::msg("not a biguint value"))?
-        };
-        witness_vec.push(E::ScalarField::from(w))
-    }
-
-    Ok(witness_vec)
-}
-
-pub fn generate_proof_with_witness(
-    witness: Vec<BigInt>,
-    proving_key: &(ProvingKey<Curve>, ConstraintMatrices<Fr>),
-) -> Result<ArkProof<Curve>, ProofError> {
-    // If in debug mode, we measure and later print time take to compute witness
-    #[cfg(test)]
-    let now = Instant::now();
-
-    let full_assignment =
-        calculate_witness_element::<Curve>(witness).map_err(ProofError::WitnessError)?;
-
-    #[cfg(test)]
-    println!("witness generation took: {:.2?}", now.elapsed());
-
-    // Random Values
-    let mut rng = thread_rng();
-    let r = Fr::rand(&mut rng);
-    let s = Fr::rand(&mut rng);
-
-    // If in debug mode, we measure and later print time take to compute proof
-    #[cfg(test)]
-    let now = Instant::now();
-
-    let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
-        &proving_key.0,
-        r,
-        s,
-        &proving_key.1,
-        proving_key.1.num_instance_variables,
-        proving_key.1.num_constraints,
-        full_assignment.as_slice(),
-    )?;
-
-    #[cfg(test)]
-    println!("proof generation took: {:.2?}", now.elapsed());
-
-    Ok(proof)
-}
-
-/// Formats inputs for witness calculation
-///
-/// # Errors
-///
-/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
-pub fn inputs_for_witness_calculation(
-    rln_witness: &RLNWitnessInput,
-) -> Result<[(&str, Vec<Fr>); 7]> {
-    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
-
-    let mut identity_path_index = Vec::with_capacity(rln_witness.identity_path_index.len());
-    rln_witness
-        .identity_path_index
-        .iter()
-        .for_each(|v| identity_path_index.push(Fr::from(*v)));
-
-    Ok([
-        ("identitySecret", vec![rln_witness.identity_secret]),
-        ("userMessageLimit", vec![rln_witness.user_message_limit]),
-        ("messageId", vec![rln_witness.message_id]),
-        ("pathElements", rln_witness.path_elements.clone()),
-        ("identityPathIndex", identity_path_index),
-        ("x", vec![rln_witness.x]),
-        ("externalNullifier", vec![rln_witness.external_nullifier]),
-    ])
-}
-
-/// Generates a RLN proof
-///
-/// # Errors
-///
-/// Returns a [`ProofError`] if proving fails.
-pub fn generate_proof(
-    proving_key: &(ProvingKey<Curve>, ConstraintMatrices<Fr>),
-    rln_witness: &RLNWitnessInput,
-    graph_data: &[u8],
-) -> Result<ArkProof<Curve>, ProofError> {
-    let inputs = inputs_for_witness_calculation(rln_witness)?
-        .into_iter()
-        .map(|(name, values)| (name.to_string(), values));
-
-    // If in debug mode, we measure and later print time take to compute witness
-    #[cfg(test)]
-    let now = Instant::now();
-    let full_assignment = calculate_rln_witness(inputs, graph_data);
-
-    #[cfg(test)]
-    println!("witness generation took: {:.2?}", now.elapsed());
-
-    // Random Values
-    let mut rng = thread_rng();
-    let r = Fr::rand(&mut rng);
-    let s = Fr::rand(&mut rng);
-
-    // If in debug mode, we measure and later print time take to compute proof
-    #[cfg(test)]
-    let now = Instant::now();
-    let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
-        &proving_key.0,
-        r,
-        s,
-        &proving_key.1,
-        proving_key.1.num_instance_variables,
-        proving_key.1.num_constraints,
-        full_assignment.as_slice(),
-    )?;
-
-    #[cfg(test)]
-    println!("proof generation took: {:.2?}", now.elapsed());
-
-    Ok(proof)
-}
-
-/// Verifies a given RLN proof
-///
-/// # Errors
-///
-/// Returns a [`ProofError`] if verifying fails. Verification failure does not
-/// necessarily mean the proof is incorrect.
-pub fn verify_proof(
-    verifying_key: &VerifyingKey<Curve>,
-    proof: &ArkProof<Curve>,
-    proof_values: &RLNProofValues,
-) -> Result<bool, ProofError> {
-    // We re-arrange proof-values according to the circuit specification
-    let inputs = vec![
-        proof_values.y,
-        proof_values.root,
-        proof_values.nullifier,
-        proof_values.x,
-        proof_values.external_nullifier,
-    ];
-
-    // Check that the proof is valid
-    let pvk = prepare_verifying_key(verifying_key);
-    //let pr: ArkProof<Curve> = (*proof).into();
-
-    // If in debug mode, we measure and later print time take to verify proof
-    #[cfg(test)]
-    let now = Instant::now();
-
-    let verified = Groth16::<_, CircomReduction>::verify_proof(&pvk, proof, &inputs)?;
-
-    #[cfg(test)]
-    println!("verify took: {:.2?}", now.elapsed());
-
-    Ok(verified)
-}
-
-// auxiliary function for serialisation Fr to json using ark serilize
-fn ark_se<S, A: CanonicalSerialize>(a: &A, s: S) -> Result<S::Ok, S::Error>
-where
-    S: serde::Serializer,
-{
-    let mut bytes = vec![];
-    a.serialize_compressed(&mut bytes)
-        .map_err(serde::ser::Error::custom)?;
-    s.serialize_bytes(&bytes)
-}
-
-// auxiliary function for deserialisation Fr to json using ark serilize
-fn ark_de<'de, D, A: CanonicalDeserialize>(data: D) -> Result<A, D::Error>
-where
-    D: serde::de::Deserializer<'de>,
-{
-    let s: Vec<u8> = serde::de::Deserialize::deserialize(data)?;
-    let a = A::deserialize_compressed_unchecked(s.as_slice());
-    a.map_err(serde::de::Error::custom)
-}
-
-/// Converts a JSON value into [`RLNWitnessInput`] object.
-///
-/// # Errors
-///
-/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
-pub fn rln_witness_from_json(input_json: serde_json::Value) -> Result<RLNWitnessInput> {
-    let rln_witness: RLNWitnessInput = serde_json::from_value(input_json).unwrap();
-    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
-
-    Ok(rln_witness)
-}
-
-/// Converts a [`RLNWitnessInput`] object to the corresponding JSON serialization.
-///
-/// # Errors
-///
-/// Returns an error if `message_id` is not within `user_message_limit`.
-pub fn rln_witness_to_json(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
-    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
-
-    let rln_witness_json = serde_json::to_value(rln_witness)?;
-    Ok(rln_witness_json)
-}
-
-/// Converts a [`RLNWitnessInput`] object to the corresponding JSON serialization.
-/// Before serialisation the data should be translated into big int for further calculation in the witness calculator.
-///
-/// # Errors
-///
-/// Returns an error if `message_id` is not within `user_message_limit`.
-pub fn rln_witness_to_bigint_json(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
-    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
-
-    let mut path_elements = Vec::new();
-
-    for v in rln_witness.path_elements.iter() {
-        path_elements.push(to_bigint(v)?.to_str_radix(10));
-    }
-
-    let mut identity_path_index = Vec::new();
-    rln_witness
-        .identity_path_index
-        .iter()
-        .for_each(|v| identity_path_index.push(BigInt::from(*v).to_str_radix(10)));
-
-    let inputs = serde_json::json!({
-        "identitySecret": to_bigint(&rln_witness.identity_secret)?.to_str_radix(10),
-        "userMessageLimit": to_bigint(&rln_witness.user_message_limit)?.to_str_radix(10),
-        "messageId": to_bigint(&rln_witness.message_id)?.to_str_radix(10),
-        "pathElements": path_elements,
-        "identityPathIndex": identity_path_index,
-        "x": to_bigint(&rln_witness.x)?.to_str_radix(10),
-        "externalNullifier":  to_bigint(&rln_witness.external_nullifier)?.to_str_radix(10),
-    });
-
-    Ok(inputs)
-}
-
-pub fn message_id_range_check(message_id: &Fr, user_message_limit: &Fr) -> Result<()> {
-    if message_id > user_message_limit {
-        return Err(color_eyre::Report::msg(
-            "message_id is not within user_message_limit",
-        ));
-    }
-    Ok(())
-}

rln/src/protocol/keygen.rs

@@ -0,0 +1,80 @@
+use ark_std::{rand::thread_rng, UniformRand};
+use rand::SeedableRng;
+use rand_chacha::ChaCha20Rng;
+use tiny_keccak::{Hasher as _, Keccak};
+use zerokit_utils::error::ZerokitMerkleTreeError;
+
+use crate::{circuit::Fr, hashers::poseidon_hash, utils::IdSecret};
+
+/// Generates a random RLN identity using a cryptographically secure RNG.
+///
+/// Returns `(identity_secret, id_commitment)` where the commitment is `PoseidonHash(identity_secret)`.
+pub fn keygen() -> Result<(IdSecret, Fr), ZerokitMerkleTreeError> {
+    let mut rng = thread_rng();
+    let identity_secret = IdSecret::rand(&mut rng);
+    let id_commitment = poseidon_hash(&[*identity_secret.clone()])?;
+    Ok((identity_secret, id_commitment))
+}
+
+/// Generates an extended RLN identity compatible with Semaphore.
+///
+/// Returns `(identity_trapdoor, identity_nullifier, identity_secret, id_commitment)` where:
+/// - `identity_secret = PoseidonHash(identity_trapdoor, identity_nullifier)`
+/// - `id_commitment = PoseidonHash(identity_secret)`
+pub fn extended_keygen() -> Result<(Fr, Fr, Fr, Fr), ZerokitMerkleTreeError> {
+    let mut rng = thread_rng();
+    let identity_trapdoor = Fr::rand(&mut rng);
+    let identity_nullifier = Fr::rand(&mut rng);
+    let identity_secret = poseidon_hash(&[identity_trapdoor, identity_nullifier])?;
+    let id_commitment = poseidon_hash(&[identity_secret])?;
+    Ok((
+        identity_trapdoor,
+        identity_nullifier,
+        identity_secret,
+        id_commitment,
+    ))
+}
+
+/// Generates a deterministic RLN identity from a seed.
+///
+/// Uses ChaCha20 RNG seeded with Keccak-256 hash of the input.
+/// Returns `(identity_secret, id_commitment)`. Same input always produces the same identity.
+pub fn seeded_keygen(signal: &[u8]) -> Result<(Fr, Fr), ZerokitMerkleTreeError> {
+    // ChaCha20 requires a seed of exactly 32 bytes.
+    // We first hash the input seed signal to a 32 bytes array and pass this as seed to ChaCha20
+    let mut seed = [0; 32];
+    let mut hasher = Keccak::v256();
+    hasher.update(signal);
+    hasher.finalize(&mut seed);
+
+    let mut rng = ChaCha20Rng::from_seed(seed);
+    let identity_secret = Fr::rand(&mut rng);
+    let id_commitment = poseidon_hash(&[identity_secret])?;
+    Ok((identity_secret, id_commitment))
+}
+
+/// Generates a deterministic extended RLN identity from a seed, compatible with Semaphore.
+///
+/// Uses ChaCha20 RNG seeded with Keccak-256 hash of the input.
+/// Returns `(identity_trapdoor, identity_nullifier, identity_secret, id_commitment)`.
+/// Same input always produces the same identity.
+pub fn extended_seeded_keygen(signal: &[u8]) -> Result<(Fr, Fr, Fr, Fr), ZerokitMerkleTreeError> {
+    // ChaCha20 requires a seed of exactly 32 bytes.
+    // We first hash the input seed signal to a 32 bytes array and pass this as seed to ChaCha20
+    let mut seed = [0; 32];
+    let mut hasher = Keccak::v256();
+    hasher.update(signal);
+    hasher.finalize(&mut seed);
+
+    let mut rng = ChaCha20Rng::from_seed(seed);
+    let identity_trapdoor = Fr::rand(&mut rng);
+    let identity_nullifier = Fr::rand(&mut rng);
+    let identity_secret = poseidon_hash(&[identity_trapdoor, identity_nullifier])?;
+    let id_commitment = poseidon_hash(&[identity_secret])?;
+    Ok((
+        identity_trapdoor,
+        identity_nullifier,
+        identity_secret,
+        id_commitment,
+    ))
+}

rln/src/protocol/mod.rs

@@ -0,0 +1,19 @@
+// This crate collects all the underlying primitives used to implement RLN
+
+mod keygen;
+mod proof;
+mod slashing;
+mod witness;
+
+pub use keygen::{extended_keygen, extended_seeded_keygen, keygen, seeded_keygen};
+pub use proof::{
+    bytes_be_to_rln_proof, bytes_be_to_rln_proof_values, bytes_le_to_rln_proof,
+    bytes_le_to_rln_proof_values, generate_zk_proof, generate_zk_proof_with_witness,
+    rln_proof_to_bytes_be, rln_proof_to_bytes_le, rln_proof_values_to_bytes_be,
+    rln_proof_values_to_bytes_le, verify_zk_proof, RLNProof, RLNProofValues,
+};
+pub use slashing::recover_id_secret;
+pub use witness::{
+    bytes_be_to_rln_witness, bytes_le_to_rln_witness, compute_tree_root, proof_values_from_witness,
+    rln_witness_to_bigint_json, rln_witness_to_bytes_be, rln_witness_to_bytes_le, RLNWitnessInput,
+};

rln/src/protocol/proof.rs

@@ -0,0 +1,345 @@
+use ark_ff::PrimeField;
+use ark_groth16::{prepare_verifying_key, Groth16};
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
+use ark_std::{rand::thread_rng, UniformRand};
+use num_bigint::BigInt;
+use num_traits::Signed;
+
+use super::witness::{inputs_for_witness_calculation, RLNWitnessInput};
+use crate::{
+    circuit::{
+        iden3calc::calc_witness, qap::CircomReduction, Curve, Fr, Proof, VerifyingKey, Zkey,
+        COMPRESS_PROOF_SIZE,
+    },
+    error::ProtocolError,
+    utils::{bytes_be_to_fr, bytes_le_to_fr, fr_to_bytes_be, fr_to_bytes_le, FR_BYTE_SIZE},
+};
+
+/// Complete RLN proof.
+///
+/// Combines the Groth16 proof with its public values.
+#[derive(Debug, PartialEq, Clone)]
+pub struct RLNProof {
+    pub proof: Proof,
+    pub proof_values: RLNProofValues,
+}
+
+/// Public values for RLN proof verification.
+///
+/// Contains the circuit's public inputs and outputs. Used in proof verification
+/// and identity secret recovery when rate limit violations are detected.
+#[derive(Debug, PartialEq, Clone, Copy)]
+pub struct RLNProofValues {
+    // Public outputs:
+    pub y: Fr,
+    pub nullifier: Fr,
+    pub root: Fr,
+    // Public Inputs:
+    pub x: Fr,
+    pub external_nullifier: Fr,
+}
+
+/// Serializes RLN proof values to little-endian bytes.
+pub fn rln_proof_values_to_bytes_le(rln_proof_values: &RLNProofValues) -> Vec<u8> {
+    // Calculate capacity for Vec:
+    // 5 field elements: root, external_nullifier, x, y, nullifier
+    let mut bytes = Vec::with_capacity(FR_BYTE_SIZE * 5);
+
+    bytes.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.root));
+    bytes.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.external_nullifier));
+    bytes.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.x));
+    bytes.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.y));
+    bytes.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.nullifier));
+
+    bytes
+}
+
+/// Serializes RLN proof values to big-endian bytes.
+pub fn rln_proof_values_to_bytes_be(rln_proof_values: &RLNProofValues) -> Vec<u8> {
+    // Calculate capacity for Vec:
+    // 5 field elements: root, external_nullifier, x, y, nullifier
+    let mut bytes = Vec::with_capacity(FR_BYTE_SIZE * 5);
+
+    bytes.extend_from_slice(&fr_to_bytes_be(&rln_proof_values.root));
+    bytes.extend_from_slice(&fr_to_bytes_be(&rln_proof_values.external_nullifier));
+    bytes.extend_from_slice(&fr_to_bytes_be(&rln_proof_values.x));
+    bytes.extend_from_slice(&fr_to_bytes_be(&rln_proof_values.y));
+    bytes.extend_from_slice(&fr_to_bytes_be(&rln_proof_values.nullifier));
+
+    bytes
+}
+
+/// Deserializes RLN proof values from little-endian bytes.
+///
+/// Format: `[ root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]`
+///
+/// Returns the deserialized proof values and the number of bytes read.
+pub fn bytes_le_to_rln_proof_values(
+    bytes: &[u8],
+) -> Result<(RLNProofValues, usize), ProtocolError> {
+    let mut read: usize = 0;
+
+    let (root, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (external_nullifier, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (x, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (y, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (nullifier, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    Ok((
+        RLNProofValues {
+            y,
+            nullifier,
+            root,
+            x,
+            external_nullifier,
+        },
+        read,
+    ))
+}
+
+/// Deserializes RLN proof values from big-endian bytes.
+///
+/// Format: `[ root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]`
+///
+/// Returns the deserialized proof values and the number of bytes read.
+pub fn bytes_be_to_rln_proof_values(
+    bytes: &[u8],
+) -> Result<(RLNProofValues, usize), ProtocolError> {
+    let mut read: usize = 0;
+
+    let (root, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (external_nullifier, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (x, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (y, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (nullifier, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    Ok((
+        RLNProofValues {
+            y,
+            nullifier,
+            root,
+            x,
+            external_nullifier,
+        },
+        read,
+    ))
+}
+
+/// Serializes RLN proof to little-endian bytes.
+///
+/// Note: The Groth16 proof is always serialized in LE format (arkworks behavior),
+/// while proof_values are serialized in LE format.
+pub fn rln_proof_to_bytes_le(rln_proof: &RLNProof) -> Result<Vec<u8>, ProtocolError> {
+    // Calculate capacity for Vec:
+    // - 128 bytes for compressed Groth16 proof
+    // - 5 field elements for proof values (root, external_nullifier, x, y, nullifier)
+    let mut bytes = Vec::with_capacity(COMPRESS_PROOF_SIZE + FR_BYTE_SIZE * 5);
+
+    // Serialize proof (always LE format from arkworks)
+    rln_proof.proof.serialize_compressed(&mut bytes)?;
+
+    // Serialize proof values in LE
+    let proof_values_bytes = rln_proof_values_to_bytes_le(&rln_proof.proof_values);
+    bytes.extend_from_slice(&proof_values_bytes);
+
+    Ok(bytes)
+}
+
+/// Serializes RLN proof to big-endian bytes.
+///
+/// Note: The Groth16 proof is always serialized in LE format (arkworks behavior),
+/// while proof_values are serialized in BE format. This creates a mixed-endian format.
+pub fn rln_proof_to_bytes_be(rln_proof: &RLNProof) -> Result<Vec<u8>, ProtocolError> {
+    // Calculate capacity for Vec:
+    // - 128 bytes for compressed Groth16 proof
+    // - 5 field elements for proof values (root, external_nullifier, x, y, nullifier)
+    let mut bytes = Vec::with_capacity(COMPRESS_PROOF_SIZE + FR_BYTE_SIZE * 5);
+
+    // Serialize proof (always LE format from arkworks)
+    rln_proof.proof.serialize_compressed(&mut bytes)?;
+
+    // Serialize proof values in BE
+    let proof_values_bytes = rln_proof_values_to_bytes_be(&rln_proof.proof_values);
+    bytes.extend_from_slice(&proof_values_bytes);
+
+    Ok(bytes)
+}
+
+/// Deserializes RLN proof from little-endian bytes.
+///
+/// Format: `[ proof<128,LE> | root<32,LE> | external_nullifier<32,LE> | x<32,LE> | y<32,LE> | nullifier<32,LE> ]`
+///
+/// Returns the deserialized proof and the number of bytes read.
+pub fn bytes_le_to_rln_proof(bytes: &[u8]) -> Result<(RLNProof, usize), ProtocolError> {
+    let mut read: usize = 0;
+
+    // Deserialize proof (always LE from arkworks)
+    let proof = Proof::deserialize_compressed(&bytes[read..read + COMPRESS_PROOF_SIZE])?;
+    read += COMPRESS_PROOF_SIZE;
+
+    // Deserialize proof values
+    let (values, el_size) = bytes_le_to_rln_proof_values(&bytes[read..])?;
+    read += el_size;
+
+    Ok((
+        RLNProof {
+            proof,
+            proof_values: values,
+        },
+        read,
+    ))
+}
+
+/// Deserializes RLN proof from big-endian bytes.
+///
+/// Format: `[ proof<128,LE> | root<32,BE> | external_nullifier<32,BE> | x<32,BE> | y<32,BE> | nullifier<32,BE> ]`
+///
+/// Note: Mixed-endian format - proof is LE (arkworks), proof_values are BE.
+///
+/// Returns the deserialized proof and the number of bytes read.
+pub fn bytes_be_to_rln_proof(bytes: &[u8]) -> Result<(RLNProof, usize), ProtocolError> {
+    let mut read: usize = 0;
+
+    // Deserialize proof (always LE from arkworks)
+    let proof = Proof::deserialize_compressed(&bytes[read..read + COMPRESS_PROOF_SIZE])?;
+    read += COMPRESS_PROOF_SIZE;
+
+    // Deserialize proof values
+    let (values, el_size) = bytes_be_to_rln_proof_values(&bytes[read..])?;
+    read += el_size;
+
+    Ok((
+        RLNProof {
+            proof,
+            proof_values: values,
+        },
+        read,
+    ))
+}
+
+// zkSNARK proof generation and verification
+
+/// Converts calculated witness (BigInt) to field elements.
+fn calculated_witness_to_field_elements<E: ark_ec::pairing::Pairing>(
+    calculated_witness: Vec<BigInt>,
+) -> Result<Vec<E::ScalarField>, ProtocolError> {
+    let modulus = <E::ScalarField as PrimeField>::MODULUS;
+
+    // convert it to field elements
+    let mut field_elements = vec![];
+    for w in calculated_witness.into_iter() {
+        let w = if w.sign() == num_bigint::Sign::Minus {
+            // Need to negate the witness element if negative
+            modulus.into()
+                - w.abs()
+                    .to_biguint()
+                    .ok_or(ProtocolError::BigUintConversion(w))?
+        } else {
+            w.to_biguint().ok_or(ProtocolError::BigUintConversion(w))?
+        };
+        field_elements.push(E::ScalarField::from(w))
+    }
+
+    Ok(field_elements)
+}
+
+/// Generates a zkSNARK proof from pre-calculated witness values.
+///
+/// Use this when witness calculation is performed externally.
+pub fn generate_zk_proof_with_witness(
+    calculated_witness: Vec<BigInt>,
+    zkey: &Zkey,
+) -> Result<Proof, ProtocolError> {
+    let full_assignment = calculated_witness_to_field_elements::<Curve>(calculated_witness)?;
+
+    // Random Values
+    let mut rng = thread_rng();
+    let r = Fr::rand(&mut rng);
+    let s = Fr::rand(&mut rng);
+
+    let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
+        &zkey.0,
+        r,
+        s,
+        &zkey.1,
+        zkey.1.num_instance_variables,
+        zkey.1.num_constraints,
+        full_assignment.as_slice(),
+    )?;
+
+    Ok(proof)
+}
+
+/// Generates a zkSNARK proof from witness input using the provided circuit data.
+pub fn generate_zk_proof(
+    zkey: &Zkey,
+    witness: &RLNWitnessInput,
+    graph_data: &[u8],
+) -> Result<Proof, ProtocolError> {
+    let inputs = inputs_for_witness_calculation(witness)?
+        .into_iter()
+        .map(|(name, values)| (name.to_string(), values));
+
+    let full_assignment = calc_witness(inputs, graph_data)?;
+
+    // Random Values
+    let mut rng = thread_rng();
+    let r = Fr::rand(&mut rng);
+    let s = Fr::rand(&mut rng);
+
+    let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
+        &zkey.0,
+        r,
+        s,
+        &zkey.1,
+        zkey.1.num_instance_variables,
+        zkey.1.num_constraints,
+        full_assignment.as_slice(),
+    )?;
+
+    Ok(proof)
+}
+
+/// Verifies a zkSNARK proof against the verifying key and public values.
+///
+/// Returns `true` if the proof is cryptographically valid, `false` if verification fails.
+/// Note: Verification failure may occur due to proof computation errors, not necessarily malicious proofs.
+pub fn verify_zk_proof(
+    verifying_key: &VerifyingKey,
+    proof: &Proof,
+    proof_values: &RLNProofValues,
+) -> Result<bool, ProtocolError> {
+    // We re-arrange proof-values according to the circuit specification
+    let inputs = vec![
+        proof_values.y,
+        proof_values.root,
+        proof_values.nullifier,
+        proof_values.x,
+        proof_values.external_nullifier,
+    ];
+
+    // Check that the proof is valid
+    let pvk = prepare_verifying_key(verifying_key);
+
+    let verified = Groth16::<_, CircomReduction>::verify_proof(&pvk, proof, &inputs)?;
+
+    Ok(verified)
+}

rln/src/protocol/slashing.rs

@@ -0,0 +1,55 @@
+use ark_ff::AdditiveGroup;
+
+use super::proof::RLNProofValues;
+use crate::{circuit::Fr, error::ProtocolError, utils::IdSecret};
+
+/// Computes identity secret from two (x, y) shares.
+fn compute_id_secret(share1: (Fr, Fr), share2: (Fr, Fr)) -> Result<IdSecret, ProtocolError> {
+    // Assuming a0 is the identity secret and a1 = poseidonHash([a0, external_nullifier]),
+    // a (x,y) share satisfies the following relation
+    // y = a_0 + x * a_1
+    let (x1, y1) = share1;
+    let (x2, y2) = share2;
+
+    // If the two input shares were computed for the same external_nullifier and identity secret, we can recover the latter
+    // y1 = a_0 + x1 * a_1
+    // y2 = a_0 + x2 * a_1
+
+    if (x1 - x2) != Fr::ZERO {
+        let a_1 = (y1 - y2) / (x1 - x2);
+        let mut a_0 = y1 - x1 * a_1;
+
+        // If shares come from the same polynomial, a0 is correctly recovered and a1 = poseidonHash([a0, external_nullifier])
+        let id_secret = IdSecret::from(&mut a_0);
+        Ok(id_secret)
+    } else {
+        Err(ProtocolError::DivisionByZero)
+    }
+}
+
+/// Recovers identity secret from two proof shares with the same external nullifier.
+///
+/// When a user violates rate limits by generating multiple proofs in the same epoch,
+/// their shares can be used to recover their identity secret through polynomial interpolation.
+pub fn recover_id_secret(
+    rln_proof_values_1: &RLNProofValues,
+    rln_proof_values_2: &RLNProofValues,
+) -> Result<IdSecret, ProtocolError> {
+    let external_nullifier_1 = rln_proof_values_1.external_nullifier;
+    let external_nullifier_2 = rln_proof_values_2.external_nullifier;
+
+    // We continue only if the proof values are for the same external nullifier
+    if external_nullifier_1 != external_nullifier_2 {
+        return Err(ProtocolError::ExternalNullifierMismatch(
+            external_nullifier_1,
+            external_nullifier_2,
+        ));
+    }
+
+    // We extract the two shares
+    let share1 = (rln_proof_values_1.x, rln_proof_values_1.y);
+    let share2 = (rln_proof_values_2.x, rln_proof_values_2.y);
+
+    // We recover the secret
+    compute_id_secret(share1, share2)
+}

rln/src/protocol/witness.rs

@@ -0,0 +1,354 @@
+use zeroize::Zeroize;
+
+use super::proof::RLNProofValues;
+use crate::{
+    circuit::Fr,
+    error::ProtocolError,
+    hashers::poseidon_hash,
+    utils::{
+        bytes_be_to_fr, bytes_be_to_vec_fr, bytes_be_to_vec_u8, bytes_le_to_fr, bytes_le_to_vec_fr,
+        bytes_le_to_vec_u8, fr_to_bytes_be, fr_to_bytes_le, to_bigint, vec_fr_to_bytes_be,
+        vec_fr_to_bytes_le, vec_u8_to_bytes_be, vec_u8_to_bytes_le, FrOrSecret, IdSecret,
+        FR_BYTE_SIZE,
+    },
+};
+
+/// Witness input for RLN proof generation.
+///
+/// Contains the identity credentials, merkle proof, rate-limiting parameters,
+/// and signal binding data required to generate a Groth16 proof for the RLN protocol.
+#[derive(Debug, PartialEq, Clone)]
+pub struct RLNWitnessInput {
+    identity_secret: IdSecret,
+    user_message_limit: Fr,
+    message_id: Fr,
+    path_elements: Vec<Fr>,
+    identity_path_index: Vec<u8>,
+    x: Fr,
+    external_nullifier: Fr,
+}
+
+impl RLNWitnessInput {
+    pub fn new(
+        identity_secret: IdSecret,
+        user_message_limit: Fr,
+        message_id: Fr,
+        path_elements: Vec<Fr>,
+        identity_path_index: Vec<u8>,
+        x: Fr,
+        external_nullifier: Fr,
+    ) -> Result<Self, ProtocolError> {
+        // Message ID range check
+        if message_id > user_message_limit {
+            return Err(ProtocolError::InvalidMessageId(
+                message_id,
+                user_message_limit,
+            ));
+        }
+
+        // Merkle proof length check
+        let path_elements_len = path_elements.len();
+        let identity_path_index_len = identity_path_index.len();
+        if path_elements_len != identity_path_index_len {
+            return Err(ProtocolError::InvalidMerkleProofLength(
+                path_elements_len,
+                identity_path_index_len,
+            ));
+        }
+
+        Ok(Self {
+            identity_secret,
+            user_message_limit,
+            message_id,
+            path_elements,
+            identity_path_index,
+            x,
+            external_nullifier,
+        })
+    }
+
+    pub fn identity_secret(&self) -> &IdSecret {
+        &self.identity_secret
+    }
+
+    pub fn user_message_limit(&self) -> &Fr {
+        &self.user_message_limit
+    }
+
+    pub fn message_id(&self) -> &Fr {
+        &self.message_id
+    }
+
+    pub fn path_elements(&self) -> &[Fr] {
+        &self.path_elements
+    }
+
+    pub fn identity_path_index(&self) -> &[u8] {
+        &self.identity_path_index
+    }
+
+    pub fn x(&self) -> &Fr {
+        &self.x
+    }
+
+    pub fn external_nullifier(&self) -> &Fr {
+        &self.external_nullifier
+    }
+}
+
+/// Serializes an RLN witness to little-endian bytes.
+pub fn rln_witness_to_bytes_le(witness: &RLNWitnessInput) -> Result<Vec<u8>, ProtocolError> {
+    // Calculate capacity for Vec:
+    // - 5 fixed field elements: identity_secret, user_message_limit, message_id, x, external_nullifier
+    // - variable number of path elements
+    // - identity_path_index (variable size)
+    let mut bytes: Vec<u8> = Vec::with_capacity(
+        FR_BYTE_SIZE * (5 + witness.path_elements.len()) + witness.identity_path_index.len(),
+    );
+    bytes.extend_from_slice(&witness.identity_secret.to_bytes_le());
+    bytes.extend_from_slice(&fr_to_bytes_le(&witness.user_message_limit));
+    bytes.extend_from_slice(&fr_to_bytes_le(&witness.message_id));
+    bytes.extend_from_slice(&vec_fr_to_bytes_le(&witness.path_elements));
+    bytes.extend_from_slice(&vec_u8_to_bytes_le(&witness.identity_path_index));
+    bytes.extend_from_slice(&fr_to_bytes_le(&witness.x));
+    bytes.extend_from_slice(&fr_to_bytes_le(&witness.external_nullifier));
+
+    Ok(bytes)
+}
+
+/// Serializes an RLN witness to big-endian bytes.
+pub fn rln_witness_to_bytes_be(witness: &RLNWitnessInput) -> Result<Vec<u8>, ProtocolError> {
+    // Calculate capacity for Vec:
+    // - 5 fixed field elements: identity_secret, user_message_limit, message_id, x, external_nullifier
+    // - variable number of path elements
+    // - identity_path_index (variable size)
+    let mut bytes: Vec<u8> = Vec::with_capacity(
+        FR_BYTE_SIZE * (5 + witness.path_elements.len()) + witness.identity_path_index.len(),
+    );
+    bytes.extend_from_slice(&witness.identity_secret.to_bytes_be());
+    bytes.extend_from_slice(&fr_to_bytes_be(&witness.user_message_limit));
+    bytes.extend_from_slice(&fr_to_bytes_be(&witness.message_id));
+    bytes.extend_from_slice(&vec_fr_to_bytes_be(&witness.path_elements));
+    bytes.extend_from_slice(&vec_u8_to_bytes_be(&witness.identity_path_index));
+    bytes.extend_from_slice(&fr_to_bytes_be(&witness.x));
+    bytes.extend_from_slice(&fr_to_bytes_be(&witness.external_nullifier));
+
+    Ok(bytes)
+}
+
+/// Deserializes an RLN witness from little-endian bytes.
+///
+/// Format: `[ identity_secret<32> | user_message_limit<32> | message_id<32> | path_elements<var> | identity_path_index<var> | x<32> | external_nullifier<32> ]`
+///
+/// Returns the deserialized witness and the number of bytes read.
+pub fn bytes_le_to_rln_witness(bytes: &[u8]) -> Result<(RLNWitnessInput, usize), ProtocolError> {
+    let mut read: usize = 0;
+
+    let (identity_secret, el_size) = IdSecret::from_bytes_le(&bytes[read..])?;
+    read += el_size;
+
+    let (user_message_limit, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (message_id, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (path_elements, el_size) = bytes_le_to_vec_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (identity_path_index, el_size) = bytes_le_to_vec_u8(&bytes[read..])?;
+    read += el_size;
+
+    let (x, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (external_nullifier, el_size) = bytes_le_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    if bytes.len() != read {
+        return Err(ProtocolError::InvalidReadLen(bytes.len(), read));
+    }
+
+    Ok((
+        RLNWitnessInput::new(
+            identity_secret,
+            user_message_limit,
+            message_id,
+            path_elements,
+            identity_path_index,
+            x,
+            external_nullifier,
+        )?,
+        read,
+    ))
+}
+
+/// Deserializes an RLN witness from big-endian bytes.
+///
+/// Format: `[ identity_secret<32> | user_message_limit<32> | message_id<32> | path_elements<var> | identity_path_index<var> | x<32> | external_nullifier<32> ]`
+///
+/// Returns the deserialized witness and the number of bytes read.
+pub fn bytes_be_to_rln_witness(bytes: &[u8]) -> Result<(RLNWitnessInput, usize), ProtocolError> {
+    let mut read: usize = 0;
+
+    let (identity_secret, el_size) = IdSecret::from_bytes_be(&bytes[read..])?;
+    read += el_size;
+
+    let (user_message_limit, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (message_id, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (path_elements, el_size) = bytes_be_to_vec_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (identity_path_index, el_size) = bytes_be_to_vec_u8(&bytes[read..])?;
+    read += el_size;
+
+    let (x, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    let (external_nullifier, el_size) = bytes_be_to_fr(&bytes[read..])?;
+    read += el_size;
+
+    if bytes.len() != read {
+        return Err(ProtocolError::InvalidReadLen(bytes.len(), read));
+    }
+
+    Ok((
+        RLNWitnessInput::new(
+            identity_secret,
+            user_message_limit,
+            message_id,
+            path_elements,
+            identity_path_index,
+            x,
+            external_nullifier,
+        )?,
+        read,
+    ))
+}
+
+/// Converts RLN witness to JSON with BigInt string representation for witness calculator.
+pub fn rln_witness_to_bigint_json(
+    witness: &RLNWitnessInput,
+) -> Result<serde_json::Value, ProtocolError> {
+    use num_bigint::BigInt;
+
+    let mut path_elements = Vec::new();
+
+    for v in witness.path_elements.iter() {
+        path_elements.push(to_bigint(v).to_str_radix(10));
+    }
+
+    let mut identity_path_index = Vec::new();
+    witness
+        .identity_path_index
+        .iter()
+        .for_each(|v| identity_path_index.push(BigInt::from(*v).to_str_radix(10)));
+
+    let inputs = serde_json::json!({
+        "identitySecret": to_bigint(&witness.identity_secret).to_str_radix(10),
+        "userMessageLimit": to_bigint(&witness.user_message_limit).to_str_radix(10),
+        "messageId": to_bigint(&witness.message_id).to_str_radix(10),
+        "pathElements": path_elements,
+        "identityPathIndex": identity_path_index,
+        "x": to_bigint(&witness.x).to_str_radix(10),
+        "externalNullifier":  to_bigint(&witness.external_nullifier).to_str_radix(10),
+    });
+
+    Ok(inputs)
+}
+
+/// Computes RLN proof values from witness input.
+///
+/// Calculates the public outputs (y, nullifier, root) that will be part of the proof.
+pub fn proof_values_from_witness(
+    witness: &RLNWitnessInput,
+) -> Result<RLNProofValues, ProtocolError> {
+    // y share
+    let a_0 = &witness.identity_secret;
+    let mut to_hash = [**a_0, witness.external_nullifier, witness.message_id];
+    let a_1 = poseidon_hash(&to_hash)?;
+    let y = *(a_0.clone()) + witness.x * a_1;
+
+    // Nullifier
+    let nullifier = poseidon_hash(&[a_1])?;
+    to_hash[0].zeroize();
+
+    // Merkle tree root computations
+    let root = compute_tree_root(
+        &witness.identity_secret,
+        &witness.user_message_limit,
+        &witness.path_elements,
+        &witness.identity_path_index,
+    )?;
+
+    Ok(RLNProofValues {
+        y,
+        nullifier,
+        root,
+        x: witness.x,
+        external_nullifier: witness.external_nullifier,
+    })
+}
+
+/// Computes the Merkle tree root from identity credentials and Merkle membership proof.
+pub fn compute_tree_root(
+    identity_secret: &IdSecret,
+    user_message_limit: &Fr,
+    path_elements: &[Fr],
+    identity_path_index: &[u8],
+) -> Result<Fr, ProtocolError> {
+    let mut to_hash = [*identity_secret.clone()];
+    let id_commitment = poseidon_hash(&to_hash)?;
+    to_hash[0].zeroize();
+
+    let mut root = poseidon_hash(&[id_commitment, *user_message_limit])?;
+
+    for i in 0..identity_path_index.len() {
+        if identity_path_index[i] == 0 {
+            root = poseidon_hash(&[root, path_elements[i]])?;
+        } else {
+            root = poseidon_hash(&[path_elements[i], root])?;
+        }
+    }
+
+    Ok(root)
+}
+
+/// Prepares inputs for witness calculation from RLN witness input.
+pub(super) fn inputs_for_witness_calculation(
+    witness: &RLNWitnessInput,
+) -> Result<[(&str, Vec<FrOrSecret>); 7], ProtocolError> {
+    let mut identity_path_index = Vec::with_capacity(witness.identity_path_index.len());
+    witness
+        .identity_path_index
+        .iter()
+        .for_each(|v| identity_path_index.push(Fr::from(*v)));
+
+    Ok([
+        (
+            "identitySecret",
+            vec![witness.identity_secret.clone().into()],
+        ),
+        ("userMessageLimit", vec![witness.user_message_limit.into()]),
+        ("messageId", vec![witness.message_id.into()]),
+        (
+            "pathElements",
+            witness
+                .path_elements
+                .iter()
+                .cloned()
+                .map(Into::into)
+                .collect(),
+        ),
+        (
+            "identityPathIndex",
+            identity_path_index.into_iter().map(Into::into).collect(),
+        ),
+        ("x", vec![witness.x.into()]),
+        ("externalNullifier", vec![witness.external_nullifier.into()]),
+    ])
+}

rln/src/utils.rs

@@ -1,29 +1,37 @@
 // This crate provides cross-module useful utilities (mainly type conversions) not necessarily specific to RLN
 
+use std::ops::Deref;
+
 use ark_ff::PrimeField;
-use color_eyre::{Report, Result};
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
+use ark_std::UniformRand;
 use num_bigint::{BigInt, BigUint};
 use num_traits::Num;
-use serde_json::json;
-use std::io::Cursor;
+use rand::Rng;
+use ruint::aliases::U256;
+use zeroize::{Zeroize, ZeroizeOnDrop, Zeroizing};
 
-use crate::circuit::Fr;
+use crate::{circuit::Fr, error::UtilsError};
+
+/// Byte size of a field element aligned to 64-bit boundary, computed once at compile time.
+pub const FR_BYTE_SIZE: usize = {
+    // Get the modulus bit size of the field
+    let modulus_bits: u32 = Fr::MODULUS_BIT_SIZE;
+    // Alignment boundary in bits for field element serialization
+    let alignment_bits: u32 = 64;
+    // Align to the next multiple of alignment_bits and convert to bytes
+    ((modulus_bits + alignment_bits - (modulus_bits % alignment_bits)) / 8) as usize
+};
 
 #[inline(always)]
-pub fn to_bigint(el: &Fr) -> Result<BigInt> {
-    Ok(BigUint::from(*el).into())
+pub fn to_bigint(el: &Fr) -> BigInt {
+    BigUint::from(*el).into()
 }
 
 #[inline(always)]
-pub fn fr_byte_size() -> usize {
-    let mbs = <Fr as PrimeField>::MODULUS_BIT_SIZE;
-    ((mbs + 64 - (mbs % 64)) / 8) as usize
-}
-
-#[inline(always)]
-pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
+pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr, UtilsError> {
     if !(radix == 10 || radix == 16) {
-        return Err(Report::msg("wrong radix"));
+        return Err(UtilsError::WrongRadix);
     }
 
     // We remove any quote present and we trim
@@ -40,12 +48,33 @@ pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
 }
 
 #[inline(always)]
-pub fn bytes_le_to_fr(input: &[u8]) -> (Fr, usize) {
-    let el_size = fr_byte_size();
-    (
+pub fn bytes_le_to_fr(input: &[u8]) -> Result<(Fr, usize), UtilsError> {
+    let el_size = FR_BYTE_SIZE;
+    if input.len() < el_size {
+        return Err(UtilsError::InsufficientData {
+            expected: el_size,
+            actual: input.len(),
+        });
+    }
+    Ok((
         Fr::from(BigUint::from_bytes_le(&input[0..el_size])),
         el_size,
-    )
+    ))
+}
+
+#[inline(always)]
+pub fn bytes_be_to_fr(input: &[u8]) -> Result<(Fr, usize), UtilsError> {
+    let el_size = FR_BYTE_SIZE;
+    if input.len() < el_size {
+        return Err(UtilsError::InsufficientData {
+            expected: el_size,
+            actual: input.len(),
+        });
+    }
+    Ok((
+        Fr::from(BigUint::from_bytes_be(&input[0..el_size])),
+        el_size,
+    ))
 }
 
 #[inline(always)]
@@ -53,86 +82,246 @@ pub fn fr_to_bytes_le(input: &Fr) -> Vec<u8> {
     let input_biguint: BigUint = (*input).into();
     let mut res = input_biguint.to_bytes_le();
     //BigUint conversion ignores most significant zero bytes. We restore them otherwise serialization will fail (length % 8 != 0)
-    res.resize(fr_byte_size(), 0);
+    res.resize(FR_BYTE_SIZE, 0);
     res
 }
 
 #[inline(always)]
-pub fn vec_fr_to_bytes_le(input: &[Fr]) -> Result<Vec<u8>> {
+pub fn fr_to_bytes_be(input: &Fr) -> Vec<u8> {
+    let input_biguint: BigUint = (*input).into();
+    let mut res = input_biguint.to_bytes_be();
+    // For BE, insert 0 at the start of the Vec (see also fr_to_bytes_le comments)
+    let to_insert_count = FR_BYTE_SIZE.saturating_sub(res.len());
+    if to_insert_count > 0 {
+        // Insert multi 0 at index 0
+        res.splice(0..0, std::iter::repeat_n(0, to_insert_count));
+    }
+    res
+}
+
+#[inline(always)]
+pub fn vec_fr_to_bytes_le(input: &[Fr]) -> Vec<u8> {
     // Calculate capacity for Vec:
     // - 8 bytes for normalized vector length (usize)
-    // - each Fr element requires fr_byte_size() bytes (typically 32 bytes)
-    let mut bytes = Vec::with_capacity(8 + input.len() * fr_byte_size());
+    // - each Fr element requires FR_BYTE_SIZE bytes (typically 32 bytes)
+    let mut bytes = Vec::with_capacity(8 + input.len() * FR_BYTE_SIZE);
 
     // We store the vector length
-    bytes.extend_from_slice(&normalize_usize(input.len()));
+    bytes.extend_from_slice(&normalize_usize_le(input.len()));
 
     // We store each element
     for el in input {
         bytes.extend_from_slice(&fr_to_bytes_le(el));
     }
 
-    Ok(bytes)
+    bytes
 }
 
 #[inline(always)]
-pub fn vec_u8_to_bytes_le(input: &[u8]) -> Result<Vec<u8>> {
+pub fn vec_fr_to_bytes_be(input: &[Fr]) -> Vec<u8> {
+    // Calculate capacity for Vec:
+    // - 8 bytes for normalized vector length (usize)
+    // - each Fr element requires FR_BYTE_SIZE bytes (typically 32 bytes)
+    let mut bytes = Vec::with_capacity(8 + input.len() * FR_BYTE_SIZE);
+
+    // We store the vector length
+    bytes.extend_from_slice(&normalize_usize_be(input.len()));
+
+    // We store each element
+    for el in input {
+        bytes.extend_from_slice(&fr_to_bytes_be(el));
+    }
+
+    bytes
+}
+
+#[inline(always)]
+pub fn vec_u8_to_bytes_le(input: &[u8]) -> Vec<u8> {
     // Calculate capacity for Vec:
     // - 8 bytes for normalized vector length (usize)
     // - variable length input data
     let mut bytes = Vec::with_capacity(8 + input.len());
 
     // We store the vector length
-    bytes.extend_from_slice(&normalize_usize(input.len()));
+    bytes.extend_from_slice(&normalize_usize_le(input.len()));
 
     // We store the input
     bytes.extend_from_slice(input);
 
-    Ok(bytes)
+    bytes
 }
 
 #[inline(always)]
-pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize)> {
-    let mut read: usize = 0;
+pub fn vec_u8_to_bytes_be(input: &[u8]) -> Vec<u8> {
+    // Calculate capacity for Vec:
+    // - 8 bytes for normalized vector length (usize)
+    // - variable length input data
+    let mut bytes = Vec::with_capacity(8 + input.len());
 
+    // We store the vector length
+    bytes.extend_from_slice(&normalize_usize_be(input.len()));
+
+    // We store the input
+    bytes.extend_from_slice(input);
+
+    bytes
+}
+
+#[inline(always)]
+pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize), UtilsError> {
+    let mut read: usize = 0;
+    if input.len() < 8 {
+        return Err(UtilsError::InsufficientData {
+            expected: 8,
+            actual: input.len(),
+        });
+    }
     let len = usize::try_from(u64::from_le_bytes(input[0..8].try_into()?))?;
     read += 8;
-
+    if input.len() < 8 + len {
+        return Err(UtilsError::InsufficientData {
+            expected: 8 + len,
+            actual: input.len(),
+        });
+    }
     let res = input[8..8 + len].to_vec();
     read += res.len();
-
     Ok((res, read))
 }
 
 #[inline(always)]
-pub fn bytes_le_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize)> {
+pub fn bytes_be_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize), UtilsError> {
     let mut read: usize = 0;
-    let mut res: Vec<Fr> = Vec::new();
+    if input.len() < 8 {
+        return Err(UtilsError::InsufficientData {
+            expected: 8,
+            actual: input.len(),
+        });
+    }
+    let len = usize::try_from(u64::from_be_bytes(input[0..8].try_into()?))?;
+    read += 8;
+    if input.len() < 8 + len {
+        return Err(UtilsError::InsufficientData {
+            expected: 8 + len,
+            actual: input.len(),
+        });
+    }
+    let res = input[8..8 + len].to_vec();
+    read += res.len();
+    Ok((res, read))
+}
 
+#[inline(always)]
+pub fn bytes_le_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize), UtilsError> {
+    let mut read: usize = 0;
+    if input.len() < 8 {
+        return Err(UtilsError::InsufficientData {
+            expected: 8,
+            actual: input.len(),
+        });
+    }
     let len = usize::try_from(u64::from_le_bytes(input[0..8].try_into()?))?;
     read += 8;
-
-    let el_size = fr_byte_size();
+    let el_size = FR_BYTE_SIZE;
+    if input.len() < 8 + len * el_size {
+        return Err(UtilsError::InsufficientData {
+            expected: 8 + len * el_size,
+            actual: input.len(),
+        });
+    }
+    let mut res: Vec<Fr> = Vec::with_capacity(len);
     for i in 0..len {
-        let (curr_el, _) = bytes_le_to_fr(&input[8 + el_size * i..8 + el_size * (i + 1)]);
+        let (curr_el, _) = bytes_le_to_fr(&input[8 + el_size * i..8 + el_size * (i + 1)])?;
         res.push(curr_el);
         read += el_size;
     }
-
     Ok((res, read))
 }
 
 #[inline(always)]
-pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>> {
+pub fn bytes_be_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize), UtilsError> {
+    let mut read: usize = 0;
+    if input.len() < 8 {
+        return Err(UtilsError::InsufficientData {
+            expected: 8,
+            actual: input.len(),
+        });
+    }
+    let len = usize::try_from(u64::from_be_bytes(input[0..8].try_into()?))?;
+    read += 8;
+    let el_size = FR_BYTE_SIZE;
+    if input.len() < 8 + len * el_size {
+        return Err(UtilsError::InsufficientData {
+            expected: 8 + len * el_size,
+            actual: input.len(),
+        });
+    }
+    let mut res: Vec<Fr> = Vec::with_capacity(len);
+    for i in 0..len {
+        let (curr_el, _) = bytes_be_to_fr(&input[8 + el_size * i..8 + el_size * (i + 1)])?;
+        res.push(curr_el);
+        read += el_size;
+    }
+    Ok((res, read))
+}
+
+#[inline(always)]
+pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>, UtilsError> {
+    if input.len() < 8 {
+        return Err(UtilsError::InsufficientData {
+            expected: 8,
+            actual: input.len(),
+        });
+    }
     let nof_elem = usize::try_from(u64::from_le_bytes(input[0..8].try_into()?))?;
     if nof_elem == 0 {
         Ok(vec![])
     } else {
-        let elements: Vec<usize> = input[8..]
-            .chunks(8)
-            .map(|ch| usize::from_le_bytes(ch[0..8].try_into().unwrap()))
-            .collect();
-        Ok(elements)
+        if input.len() < 8 + nof_elem * 8 {
+            return Err(UtilsError::InsufficientData {
+                expected: 8 + nof_elem * 8,
+                actual: input.len(),
+            });
+        }
+        input[8..]
+            .chunks_exact(8)
+            .take(nof_elem)
+            .map(|ch| {
+                ch.try_into()
+                    .map(usize::from_le_bytes)
+                    .map_err(UtilsError::FromSlice)
+            })
+            .collect()
+    }
+}
+
+#[inline(always)]
+pub fn bytes_be_to_vec_usize(input: &[u8]) -> Result<Vec<usize>, UtilsError> {
+    if input.len() < 8 {
+        return Err(UtilsError::InsufficientData {
+            expected: 8,
+            actual: input.len(),
+        });
+    }
+    let nof_elem = usize::try_from(u64::from_be_bytes(input[0..8].try_into()?))?;
+    if nof_elem == 0 {
+        Ok(vec![])
+    } else {
+        if input.len() < 8 + nof_elem * 8 {
+            return Err(UtilsError::InsufficientData {
+                expected: 8 + nof_elem * 8,
+                actual: input.len(),
+            });
+        }
+        input[8..]
+            .chunks_exact(8)
+            .take(nof_elem)
+            .map(|ch| {
+                ch.try_into()
+                    .map(usize::from_be_bytes)
+                    .map_err(UtilsError::FromSlice)
+            })
+            .collect()
     }
 }
 
@@ -140,14 +329,131 @@ pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>> {
 /// On 32-bit systems, the result is zero-padded to 8 bytes.
 /// On 64-bit systems, it directly represents the `usize` value.
 #[inline(always)]
-pub fn normalize_usize(input: usize) -> [u8; 8] {
+pub fn normalize_usize_le(input: usize) -> [u8; 8] {
     let mut bytes = [0u8; 8];
     let input_bytes = input.to_le_bytes();
     bytes[..input_bytes.len()].copy_from_slice(&input_bytes);
     bytes
 }
 
-#[inline(always)] // using for test
-pub fn generate_input_buffer() -> Cursor<String> {
-    Cursor::new(json!({}).to_string())
+/// Normalizes a `usize` into an 8-byte array, ensuring consistency across architectures.
+/// On 32-bit systems, the result is zero-padded to 8 bytes.
+/// On 64-bit systems, it directly represents the `usize` value.
+#[inline(always)]
+pub fn normalize_usize_be(input: usize) -> [u8; 8] {
+    let mut bytes = [0u8; 8];
+    let input_bytes = input.to_be_bytes();
+    let offset = 8 - input_bytes.len();
+    bytes[offset..].copy_from_slice(&input_bytes);
+    bytes
+}
+
+#[derive(
+    Debug, Zeroize, ZeroizeOnDrop, Clone, PartialEq, CanonicalSerialize, CanonicalDeserialize,
+)]
+pub struct IdSecret(Fr);
+
+impl IdSecret {
+    pub fn rand<R: Rng + ?Sized>(rng: &mut R) -> Self {
+        let mut fr = Fr::rand(rng);
+        let res = Self::from(&mut fr);
+        // No need to zeroize fr (already zeroiz'ed in from implementation)
+        #[allow(clippy::let_and_return)]
+        res
+    }
+
+    pub fn from_bytes_le(input: &[u8]) -> Result<(Self, usize), UtilsError> {
+        let el_size = FR_BYTE_SIZE;
+        if input.len() < el_size {
+            return Err(UtilsError::InsufficientData {
+                expected: el_size,
+                actual: input.len(),
+            });
+        }
+        let b_uint = BigUint::from_bytes_le(&input[0..el_size]);
+        let mut fr = Fr::from(b_uint);
+        let res = IdSecret::from(&mut fr);
+        // Note: no zeroize on b_uint as it has been moved
+        Ok((res, el_size))
+    }
+
+    pub fn from_bytes_be(input: &[u8]) -> Result<(Self, usize), UtilsError> {
+        let el_size = FR_BYTE_SIZE;
+        if input.len() < el_size {
+            return Err(UtilsError::InsufficientData {
+                expected: el_size,
+                actual: input.len(),
+            });
+        }
+        let b_uint = BigUint::from_bytes_be(&input[0..el_size]);
+        let mut fr = Fr::from(b_uint);
+        let res = IdSecret::from(&mut fr);
+        // Note: no zeroize on b_uint as it has been moved
+        Ok((res, el_size))
+    }
+
+    pub(crate) fn to_bytes_le(&self) -> Zeroizing<Vec<u8>> {
+        let input_biguint: BigUint = self.0.into();
+        let mut res = input_biguint.to_bytes_le();
+        res.resize(FR_BYTE_SIZE, 0);
+        Zeroizing::new(res)
+    }
+
+    pub(crate) fn to_bytes_be(&self) -> Zeroizing<Vec<u8>> {
+        let input_biguint: BigUint = self.0.into();
+        let mut res = input_biguint.to_bytes_be();
+        let to_insert_count = FR_BYTE_SIZE.saturating_sub(res.len());
+        if to_insert_count > 0 {
+            // Insert multi 0 at index 0
+            res.splice(0..0, std::iter::repeat_n(0, to_insert_count));
+        }
+        Zeroizing::new(res)
+    }
+
+    /// Warning: this can leak the secret value
+    /// Warning: Leaked value is of type 'U256' which implement Copy (every copy will not be zeroized)
+    pub(crate) fn to_u256(&self) -> U256 {
+        let mut big_int = self.0.into_bigint();
+        let res = U256::from_limbs(big_int.0);
+        big_int.zeroize();
+        res
+    }
+}
+
+impl From<&mut Fr> for IdSecret {
+    fn from(value: &mut Fr) -> Self {
+        let id_secret = Self(*value);
+        value.zeroize();
+        id_secret
+    }
+}
+
+impl Deref for IdSecret {
+    type Target = Fr;
+
+    /// Deref to &Fr
+    ///
+    /// Warning: this can leak the secret value
+    /// Warning: Leaked value is of type 'Fr' which implement Copy (every copy will not be zeroized)
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+#[derive(Debug, Zeroize, ZeroizeOnDrop)]
+pub(crate) enum FrOrSecret {
+    IdSecret(IdSecret),
+    Fr(Fr),
+}
+
+impl From<Fr> for FrOrSecret {
+    fn from(value: Fr) -> Self {
+        FrOrSecret::Fr(value)
+    }
+}
+
+impl From<IdSecret> for FrOrSecret {
+    fn from(value: IdSecret) -> Self {
+        FrOrSecret::IdSecret(value)
+    }
 }

rln/tests/ffi_utils.rs

@@ -0,0 +1,288 @@
+#[cfg(test)]
+mod test {
+    use rand::Rng;
+    use rln::{ffi::ffi_utils::*, prelude::*};
+
+    #[test]
+    // Tests hash to field using FFI APIs
+    fn test_seeded_keygen_ffi() {
+        // We generate a new identity pair from an input seed
+        let seed_bytes: Vec<u8> = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+        let res = match ffi_seeded_key_gen(&seed_bytes.into()) {
+            CResult {
+                ok: Some(vec_cfr),
+                err: None,
+            } => vec_cfr,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_seeded_key_gen call failed: {}", err),
+            _ => unreachable!(),
+        };
+        let identity_secret = res.first().unwrap();
+        let id_commitment = res.get(1).unwrap();
+
+        // We check against expected values
+        let expected_identity_secret_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        )
+        .unwrap();
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0xbf16d2b5c0d6f9d9d561e05bfca16a81b4b873bb063508fae360d8c74cef51f",
+            16,
+        )
+        .unwrap();
+
+        assert_eq!(*identity_secret, expected_identity_secret_seed_bytes);
+        assert_eq!(*id_commitment, expected_id_commitment_seed_bytes);
+    }
+
+    #[test]
+    // Tests hash to field using FFI APIs
+    fn test_seeded_extended_keygen_ffi() {
+        // We generate a new identity tuple from an input seed
+        let seed_bytes: Vec<u8> = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+        let key_gen = match ffi_seeded_extended_key_gen(&seed_bytes.into()) {
+            CResult {
+                ok: Some(vec_cfr),
+                err: None,
+            } => vec_cfr,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_seeded_extended_key_gen call failed: {}", err),
+            _ => unreachable!(),
+        };
+        let identity_trapdoor = *key_gen[0];
+        let identity_nullifier = *key_gen[1];
+        let identity_secret = *key_gen[2];
+        let id_commitment = *key_gen[3];
+
+        // We check against expected values
+        let expected_identity_trapdoor_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        )
+        .unwrap();
+        let expected_identity_nullifier_seed_bytes = str_to_fr(
+            "0x1f18714c7bc83b5bca9e89d404cf6f2f585bc4c0f7ed8b53742b7e2b298f50b4",
+            16,
+        )
+        .unwrap();
+        let expected_identity_secret_seed_bytes = str_to_fr(
+            "0x2aca62aaa7abaf3686fff2caf00f55ab9462dc12db5b5d4bcf3994e671f8e521",
+            16,
+        )
+        .unwrap();
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0x68b66aa0a8320d2e56842581553285393188714c48f9b17acd198b4f1734c5c",
+            16,
+        )
+        .unwrap();
+
+        assert_eq!(identity_trapdoor, expected_identity_trapdoor_seed_bytes);
+        assert_eq!(identity_nullifier, expected_identity_nullifier_seed_bytes);
+        assert_eq!(identity_secret, expected_identity_secret_seed_bytes);
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes);
+    }
+
+    #[test]
+    // Test CFr FFI functions
+    fn test_cfr_ffi() {
+        let cfr_zero = ffi_cfr_zero();
+        let fr_zero = rln::circuit::Fr::from(0u8);
+        assert_eq!(*cfr_zero, fr_zero);
+
+        let cfr_one = ffi_cfr_one();
+        let fr_one = rln::circuit::Fr::from(1u8);
+        assert_eq!(*cfr_one, fr_one);
+
+        let cfr_int = ffi_uint_to_cfr(42);
+        let fr_int = rln::circuit::Fr::from(42u8);
+        assert_eq!(*cfr_int, fr_int);
+
+        let cfr_debug_str = ffi_cfr_debug(Some(&cfr_int));
+        assert_eq!(cfr_debug_str.to_string(), "42");
+
+        let key_gen = match ffi_key_gen() {
+            CResult {
+                ok: Some(vec_cfr),
+                err: None,
+            } => vec_cfr,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_key_gen call failed: {}", err),
+            _ => unreachable!(),
+        };
+        let mut id_secret_fr = *key_gen[0];
+        let id_secret_hash = IdSecret::from(&mut id_secret_fr);
+        let id_commitment = *key_gen[1];
+        let cfr_id_secret_hash = ffi_vec_cfr_get(&key_gen, 0).unwrap();
+        assert_eq!(*cfr_id_secret_hash, *id_secret_hash);
+        let cfr_id_commitment = ffi_vec_cfr_get(&key_gen, 1).unwrap();
+        assert_eq!(*cfr_id_commitment, id_commitment);
+    }
+
+    #[test]
+    // Test Vec<u8> FFI functions
+    fn test_vec_u8_ffi() {
+        let mut rng = rand::thread_rng();
+        let signal_gen: [u8; 32] = rng.gen();
+        let signal: Vec<u8> = signal_gen.to_vec();
+
+        let bytes_le = ffi_vec_u8_to_bytes_le(&signal.clone().into());
+        let expected_le = vec_u8_to_bytes_le(&signal);
+        assert_eq!(bytes_le.iter().copied().collect::<Vec<_>>(), expected_le);
+
+        let bytes_be = ffi_vec_u8_to_bytes_be(&signal.clone().into());
+        let expected_be = vec_u8_to_bytes_be(&signal);
+        assert_eq!(bytes_be.iter().copied().collect::<Vec<_>>(), expected_be);
+
+        let signal_from_le = match ffi_bytes_le_to_vec_u8(&bytes_le) {
+            CResult {
+                ok: Some(vec_u8),
+                err: None,
+            } => vec_u8,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_bytes_le_to_vec_u8 call failed: {}", err),
+            _ => unreachable!(),
+        };
+        assert_eq!(signal_from_le.iter().copied().collect::<Vec<_>>(), signal);
+
+        let signal_from_be = match ffi_bytes_be_to_vec_u8(&bytes_be) {
+            CResult {
+                ok: Some(vec_u8),
+                err: None,
+            } => vec_u8,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_bytes_be_to_vec_u8 call failed: {}", err),
+            _ => unreachable!(),
+        };
+        assert_eq!(signal_from_be.iter().copied().collect::<Vec<_>>(), signal);
+    }
+
+    #[test]
+    // Test Vec<CFr> FFI functions
+    fn test_vec_cfr_ffi() {
+        let vec_fr = [Fr::from(1u8), Fr::from(2u8), Fr::from(3u8), Fr::from(4u8)];
+        let vec_cfr: Vec<CFr> = vec_fr.iter().map(|fr| CFr::from(*fr)).collect();
+
+        let bytes_le = ffi_vec_cfr_to_bytes_le(&vec_cfr.clone().into());
+        let expected_le = vec_fr_to_bytes_le(&vec_fr);
+        assert_eq!(bytes_le.iter().copied().collect::<Vec<_>>(), expected_le);
+
+        let bytes_be = ffi_vec_cfr_to_bytes_be(&vec_cfr.clone().into());
+        let expected_be = vec_fr_to_bytes_be(&vec_fr);
+        assert_eq!(bytes_be.iter().copied().collect::<Vec<_>>(), expected_be);
+
+        let vec_cfr_from_le = match ffi_bytes_le_to_vec_cfr(&bytes_le) {
+            CResult {
+                ok: Some(vec_cfr),
+                err: None,
+            } => vec_cfr,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_bytes_le_to_vec_cfr call failed: {}", err),
+            _ => unreachable!(),
+        };
+        assert_eq!(vec_cfr_from_le.iter().copied().collect::<Vec<_>>(), vec_cfr);
+
+        let vec_cfr_from_be = match ffi_bytes_be_to_vec_cfr(&bytes_be) {
+            CResult {
+                ok: Some(vec_cfr),
+                err: None,
+            } => vec_cfr,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_bytes_be_to_vec_cfr call failed: {}", err),
+            _ => unreachable!(),
+        };
+        assert_eq!(vec_cfr_from_be.iter().copied().collect::<Vec<_>>(), vec_cfr);
+    }
+
+    #[test]
+    // Tests hash to field using FFI APIs
+    fn test_hash_to_field_ffi() {
+        let mut rng = rand::thread_rng();
+        let signal_gen: [u8; 32] = rng.gen();
+        let signal: Vec<u8> = signal_gen.to_vec();
+
+        let cfr_le_1 = match ffi_hash_to_field_le(&signal.clone().into()) {
+            CResult {
+                ok: Some(cfr),
+                err: None,
+            } => cfr,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_hash_to_field_le call failed: {}", err),
+            _ => unreachable!(),
+        };
+        let fr_le_2 = hash_to_field_le(&signal).unwrap();
+        assert_eq!(*cfr_le_1, fr_le_2);
+
+        let cfr_be_1 = match ffi_hash_to_field_be(&signal.clone().into()) {
+            CResult {
+                ok: Some(cfr),
+                err: None,
+            } => cfr,
+            CResult {
+                ok: None,
+                err: Some(err),
+            } => panic!("ffi_hash_to_field_be call failed: {}", err),
+            _ => unreachable!(),
+        };
+        let fr_be_2 = hash_to_field_be(&signal).unwrap();
+        assert_eq!(*cfr_le_1, fr_be_2);
+
+        assert_eq!(*cfr_le_1, *cfr_be_1);
+        assert_eq!(fr_le_2, fr_be_2);
+
+        let hash_cfr_le_1 = ffi_cfr_to_bytes_le(&cfr_le_1)
+            .iter()
+            .copied()
+            .collect::<Vec<_>>();
+        let hash_fr_le_2 = fr_to_bytes_le(&fr_le_2);
+        assert_eq!(hash_cfr_le_1, hash_fr_le_2);
+
+        let hash_cfr_be_1 = ffi_cfr_to_bytes_be(&cfr_be_1)
+            .iter()
+            .copied()
+            .collect::<Vec<_>>();
+        let hash_fr_be_2 = fr_to_bytes_be(&fr_be_2);
+        assert_eq!(hash_cfr_be_1, hash_fr_be_2);
+
+        assert_ne!(hash_cfr_le_1, hash_cfr_be_1);
+        assert_ne!(hash_fr_le_2, hash_fr_be_2);
+    }
+
+    #[test]
+    // Test Poseidon hash FFI
+    fn test_poseidon_hash_pair_ffi() {
+        let input_1 = Fr::from(42u8);
+        let input_2 = Fr::from(99u8);
+
+        let expected_hash = poseidon_hash(&[input_1, input_2]).unwrap();
+        let received_hash_cfr =
+            match ffi_poseidon_hash_pair(&CFr::from(input_1), &CFr::from(input_2)) {
+                CResult {
+                    ok: Some(cfr),
+                    err: None,
+                } => cfr,
+                CResult {
+                    ok: None,
+                    err: Some(err),
+                } => panic!("ffi_poseidon_hash_pair call failed: {}", err),
+                _ => unreachable!(),
+            };
+        assert_eq!(*received_hash_cfr, expected_hash);
+    }
+}

rln/tests/poseidon_tree.rs

@@ -1,30 +1,35 @@
-////////////////////////////////////////////////////////////
-/// Tests
-////////////////////////////////////////////////////////////
+// Tests
+
+#![cfg(not(feature = "stateless"))]
 
 #[cfg(test)]
 mod test {
-    use rln::hashers::{poseidon_hash, PoseidonHash};
-    use rln::{circuit::*, poseidon_tree::PoseidonTree};
-    use utils::{FullMerkleTree, OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree};
+    use rln::prelude::*;
+    use zerokit_utils::merkle_tree::{
+        FullMerkleTree, OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree,
+    };
 
     #[test]
-    // The test is checked correctness for `FullMerkleTree` and `OptimalMerkleTree` with Poseidon hash
+    // The test checked correctness for `FullMerkleTree` and `OptimalMerkleTree` with Poseidon hash
     fn test_zerokit_merkle_implementations() {
         let sample_size = 100;
-        let leaves: Vec<Fr> = (0..sample_size).map(|s| Fr::from(s)).collect();
+        let leaves: Vec<Fr> = (0..sample_size).map(Fr::from).collect();
 
-        let mut tree_full = FullMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
-        let mut tree_opt = OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+        let mut tree_full = FullMerkleTree::<PoseidonHash>::default(DEFAULT_TREE_DEPTH).unwrap();
+        let mut tree_opt = OptimalMerkleTree::<PoseidonHash>::default(DEFAULT_TREE_DEPTH).unwrap();
 
-        for i in 0..sample_size.try_into().unwrap() {
-            tree_full.set(i, leaves[i]).unwrap();
-            let proof = tree_full.proof(i).expect("index should be set");
+        for (i, leave) in leaves
+            .into_iter()
+            .enumerate()
+            .take(sample_size.try_into().unwrap())
+        {
+            tree_full.set(i, leave).unwrap();
+            let proof = tree_full.proof(i).unwrap();
             assert_eq!(proof.leaf_index(), i);
 
-            tree_opt.set(i, leaves[i]).unwrap();
+            tree_opt.set(i, leave).unwrap();
             assert_eq!(tree_opt.root(), tree_full.root());
-            let proof = tree_opt.proof(i).expect("index should be set");
+            let proof = tree_opt.proof(i).unwrap();
             assert_eq!(proof.leaf_index(), i);
         }
 
@@ -65,7 +70,7 @@ mod test {
                 let prev_r = tree.get_subtree_root(n, idx_r).unwrap();
                 let subroot = tree.get_subtree_root(n - 1, idx_sr).unwrap();
 
-                assert_eq!(poseidon_hash(&[prev_l, prev_r]), subroot);
+                assert_eq!(poseidon_hash(&[prev_l, prev_r]).unwrap(), subroot);
             }
         }
     }
@@ -98,7 +103,7 @@ mod test {
 
         // check remove_indices_and_set_leaves inside override_range function
         assert!(tree.get_empty_leaves_indices().is_empty());
-        let leaves_2: Vec<Fr> = (0..2).map(|s| Fr::from(s as i32)).collect();
+        let leaves_2: Vec<Fr> = (0..2).map(Fr::from).collect();
         tree.override_range(0, leaves_2.clone().into_iter(), [0, 1, 2, 3].into_iter())
             .unwrap();
         assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
@@ -113,7 +118,7 @@ mod test {
             .unwrap();
         assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
 
-        let leaves_4: Vec<Fr> = (0..4).map(|s| Fr::from(s as i32)).collect();
+        let leaves_4: Vec<Fr> = (0..4).map(Fr::from).collect();
         // check if the indexes for write and delete are the same
         tree.override_range(0, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
             .unwrap();

rln/tests/protocol.rs

@@ -1,13 +1,10 @@
+#![cfg(not(feature = "stateless"))]
+
 #[cfg(test)]
 mod test {
     use ark_ff::BigInt;
-    use rln::circuit::{graph_from_folder, zkey_from_folder};
-    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
-    use rln::hashers::{hash_to_field, poseidon_hash};
-    use rln::poseidon_tree::PoseidonTree;
-    use rln::protocol::*;
-    use rln::utils::str_to_fr;
-    use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
+    use rln::prelude::*;
+    use zerokit_utils::merkle_tree::{ZerokitMerkleProof, ZerokitMerkleTree};
 
     type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
 
@@ -17,19 +14,19 @@ mod test {
         let leaf_index = 3;
 
         // generate identity
-        let identity_secret_hash = hash_to_field(b"test-merkle-proof");
-        let id_commitment = poseidon_hash(&[identity_secret_hash]);
-        let rate_commitment = poseidon_hash(&[id_commitment, 100.into()]);
+        let identity_secret = hash_to_field_le(b"test-merkle-proof").unwrap();
+        let id_commitment = poseidon_hash(&[identity_secret]).unwrap();
+        let rate_commitment = poseidon_hash(&[id_commitment, 100.into()]).unwrap();
 
         // generate merkle tree
         let default_leaf = Fr::from(0);
         let mut tree = PoseidonTree::new(
-            TEST_TREE_HEIGHT,
+            DEFAULT_TREE_DEPTH,
             default_leaf,
             ConfigOf::<PoseidonTree>::default(),
         )
         .unwrap();
-        tree.set(leaf_index, rate_commitment.into()).unwrap();
+        tree.set(leaf_index, rate_commitment).unwrap();
 
         // We check correct computation of the root
         let root = tree.root();
@@ -45,7 +42,7 @@ mod test {
             .into()
         );
 
-        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
+        let merkle_proof = tree.proof(leaf_index).unwrap();
         let path_elements = merkle_proof.get_path_elements();
         let identity_path_index = merkle_proof.get_path_index();
 
@@ -72,7 +69,7 @@ mod test {
             "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
             "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
         ]
-        .map(|e| str_to_fr(e, 16).unwrap())
+        .map(|str| str_to_fr(str, 16).unwrap())
         .to_vec();
 
         let expected_identity_path_index: Vec<u8> =
@@ -88,105 +85,77 @@ mod test {
     fn get_test_witness() -> RLNWitnessInput {
         let leaf_index = 3;
         // Generate identity pair
-        let (identity_secret_hash, id_commitment) = keygen();
+        let (identity_secret, id_commitment) = keygen().unwrap();
         let user_message_limit = Fr::from(100);
-        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]).unwrap();
 
         //// generate merkle tree
         let default_leaf = Fr::from(0);
         let mut tree = PoseidonTree::new(
-            TEST_TREE_HEIGHT,
+            DEFAULT_TREE_DEPTH,
             default_leaf,
             ConfigOf::<PoseidonTree>::default(),
         )
         .unwrap();
-        tree.set(leaf_index, rate_commitment.into()).unwrap();
+        tree.set(leaf_index, rate_commitment).unwrap();
 
-        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
+        let merkle_proof = tree.proof(leaf_index).unwrap();
 
         let signal = b"hey hey";
-        let x = hash_to_field(signal);
+        let x = hash_to_field_le(signal).unwrap();
 
         // We set the remaining values to random ones
-        let epoch = hash_to_field(b"test-epoch");
-        let rln_identifier = hash_to_field(b"test-rln-identifier");
-        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+        let epoch = hash_to_field_le(b"test-epoch").unwrap();
+        let rln_identifier = hash_to_field_le(b"test-rln-identifier").unwrap();
+        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]).unwrap();
 
-        rln_witness_from_values(
-            identity_secret_hash,
-            &merkle_proof,
+        let message_id = Fr::from(1);
+
+        RLNWitnessInput::new(
+            identity_secret,
+            user_message_limit,
+            message_id,
+            merkle_proof.get_path_elements(),
+            merkle_proof.get_path_index(),
             x,
             external_nullifier,
-            user_message_limit,
-            Fr::from(1),
         )
         .unwrap()
     }
 
-    #[test]
-    // We test a RLN proof generation and verification
-    fn test_witness_from_json() {
-        // We generate all relevant keys
-        let proving_key = zkey_from_folder();
-        let verification_key = &proving_key.0.vk;
-        let graph_data = graph_from_folder();
-        // We compute witness from the json input
-        let rln_witness = get_test_witness();
-        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
-        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
-        assert_eq!(rln_witness_deser, rln_witness);
-
-        // Let's generate a zkSNARK proof
-        let proof = generate_proof(&proving_key, &rln_witness_deser, &graph_data).unwrap();
-        let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();
-
-        // Let's verify the proof
-        let verified = verify_proof(&verification_key, &proof, &proof_values);
-
-        assert!(verified.unwrap());
-    }
-
     #[test]
     // We test a RLN proof generation and verification
     fn test_end_to_end() {
-        let rln_witness = get_test_witness();
-        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
-        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
-        assert_eq!(rln_witness_deser, rln_witness);
+        let witness = get_test_witness();
 
         // We generate all relevant keys
         let proving_key = zkey_from_folder();
-        let verification_key = &proving_key.0.vk;
         let graph_data = graph_from_folder();
 
         // Let's generate a zkSNARK proof
-        let proof = generate_proof(&proving_key, &rln_witness_deser, &graph_data).unwrap();
+        let proof = generate_zk_proof(proving_key, &witness, graph_data).unwrap();
 
-        let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();
+        let proof_values = proof_values_from_witness(&witness).unwrap();
 
         // Let's verify the proof
-        let success = verify_proof(&verification_key, &proof, &proof_values).unwrap();
+        let success = verify_zk_proof(&proving_key.0.vk, &proof, &proof_values).unwrap();
 
         assert!(success);
     }
 
     #[test]
     fn test_witness_serialization() {
-        // We test witness JSON serialization
-        let rln_witness = get_test_witness();
-        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
-        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
-        assert_eq!(rln_witness_deser, rln_witness);
+        let witness = get_test_witness();
 
         // We test witness serialization
-        let ser = serialize_witness(&rln_witness).unwrap();
-        let (deser, _) = deserialize_witness(&ser).unwrap();
-        assert_eq!(rln_witness, deser);
+        let ser = rln_witness_to_bytes_le(&witness).unwrap();
+        let (deser, _) = bytes_le_to_rln_witness(&ser).unwrap();
+        assert_eq!(witness, deser);
 
         // We test Proof values serialization
-        let proof_values = proof_values_from_witness(&rln_witness).unwrap();
-        let ser = serialize_proof_values(&proof_values);
-        let (deser, _) = deserialize_proof_values(&ser);
+        let proof_values = proof_values_from_witness(&witness).unwrap();
+        let ser = rln_proof_values_to_bytes_le(&proof_values);
+        let (deser, _) = bytes_le_to_rln_proof_values(&ser).unwrap();
         assert_eq!(proof_values, deser);
     }
 
@@ -196,10 +165,10 @@ mod test {
     fn test_seeded_keygen() {
         // Generate identity pair using a seed phrase
         let seed_phrase: &str = "A seed phrase example";
-        let (identity_secret_hash, id_commitment) = seeded_keygen(seed_phrase.as_bytes());
+        let (identity_secret, id_commitment) = seeded_keygen(seed_phrase.as_bytes()).unwrap();
 
         // We check against expected values
-        let expected_identity_secret_hash_seed_phrase = str_to_fr(
+        let expected_identity_secret_seed_phrase = str_to_fr(
             "0x20df38f3f00496f19fe7c6535492543b21798ed7cb91aebe4af8012db884eda3",
             16,
         )
@@ -210,18 +179,15 @@ mod test {
         )
         .unwrap();
 
-        assert_eq!(
-            identity_secret_hash,
-            expected_identity_secret_hash_seed_phrase
-        );
+        assert_eq!(identity_secret, expected_identity_secret_seed_phrase);
         assert_eq!(id_commitment, expected_id_commitment_seed_phrase);
 
         // Generate identity pair using an byte array
         let seed_bytes: &[u8] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
-        let (identity_secret_hash, id_commitment) = seeded_keygen(seed_bytes);
+        let (identity_secret, id_commitment) = seeded_keygen(seed_bytes).unwrap();
 
         // We check against expected values
-        let expected_identity_secret_hash_seed_bytes = str_to_fr(
+        let expected_identity_secret_seed_bytes = str_to_fr(
             "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
             16,
         )
@@ -232,19 +198,13 @@ mod test {
         )
         .unwrap();
 
-        assert_eq!(
-            identity_secret_hash,
-            expected_identity_secret_hash_seed_bytes
-        );
+        assert_eq!(identity_secret, expected_identity_secret_seed_bytes);
         assert_eq!(id_commitment, expected_id_commitment_seed_bytes);
 
         // We check again if the identity pair generated with the same seed phrase corresponds to the previously generated one
-        let (identity_secret_hash, id_commitment) = seeded_keygen(seed_phrase.as_bytes());
+        let (identity_secret, id_commitment) = seeded_keygen(seed_phrase.as_bytes()).unwrap();
 
-        assert_eq!(
-            identity_secret_hash,
-            expected_identity_secret_hash_seed_phrase
-        );
+        assert_eq!(identity_secret, expected_identity_secret_seed_phrase);
         assert_eq!(id_commitment, expected_id_commitment_seed_phrase);
     }
 }

rln/tests/utils.rs

@@ -0,0 +1,424 @@
+#[cfg(test)]
+mod test {
+    use ark_std::{rand::thread_rng, UniformRand};
+    use rln::prelude::*;
+
+    #[test]
+    fn test_normalize_usize_le() {
+        // Test basic cases
+        assert_eq!(normalize_usize_le(0), [0, 0, 0, 0, 0, 0, 0, 0]);
+        assert_eq!(normalize_usize_le(1), [1, 0, 0, 0, 0, 0, 0, 0]);
+        assert_eq!(normalize_usize_le(255), [255, 0, 0, 0, 0, 0, 0, 0]);
+        assert_eq!(normalize_usize_le(256), [0, 1, 0, 0, 0, 0, 0, 0]);
+        assert_eq!(normalize_usize_le(65535), [255, 255, 0, 0, 0, 0, 0, 0]);
+        assert_eq!(normalize_usize_le(65536), [0, 0, 1, 0, 0, 0, 0, 0]);
+
+        // Test 32-bit boundary
+        assert_eq!(
+            normalize_usize_le(4294967295),
+            [255, 255, 255, 255, 0, 0, 0, 0]
+        );
+        assert_eq!(normalize_usize_le(4294967296), [0, 0, 0, 0, 1, 0, 0, 0]);
+
+        // Test maximum value
+        assert_eq!(
+            normalize_usize_le(usize::MAX),
+            [255, 255, 255, 255, 255, 255, 255, 255]
+        );
+
+        // Test that result is always 8 bytes
+        assert_eq!(normalize_usize_le(0).len(), 8);
+        assert_eq!(normalize_usize_le(usize::MAX).len(), 8);
+    }
+
+    #[test]
+    fn test_normalize_usize_be() {
+        // Test basic cases
+        assert_eq!(normalize_usize_be(0), [0, 0, 0, 0, 0, 0, 0, 0]);
+        assert_eq!(normalize_usize_be(1), [0, 0, 0, 0, 0, 0, 0, 1]);
+        assert_eq!(normalize_usize_be(255), [0, 0, 0, 0, 0, 0, 0, 255]);
+        assert_eq!(normalize_usize_be(256), [0, 0, 0, 0, 0, 0, 1, 0]);
+        assert_eq!(normalize_usize_be(65535), [0, 0, 0, 0, 0, 0, 255, 255]);
+        assert_eq!(normalize_usize_be(65536), [0, 0, 0, 0, 0, 1, 0, 0]);
+
+        // Test 32-bit boundary
+        assert_eq!(
+            normalize_usize_be(4294967295),
+            [0, 0, 0, 0, 255, 255, 255, 255]
+        );
+        assert_eq!(normalize_usize_be(4294967296), [0, 0, 0, 1, 0, 0, 0, 0]);
+
+        // Test maximum value
+        assert_eq!(
+            normalize_usize_be(usize::MAX),
+            [255, 255, 255, 255, 255, 255, 255, 255]
+        );
+
+        // Test that result is always 8 bytes
+        assert_eq!(normalize_usize_be(0).len(), 8);
+        assert_eq!(normalize_usize_be(usize::MAX).len(), 8);
+    }
+
+    #[test]
+    fn test_normalize_usize_endianness() {
+        // Test that little-endian and big-endian produce different results for non-zero values
+        let test_values = vec![1, 255, 256, 65535, 65536, 4294967295, 4294967296];
+
+        for &value in &test_values {
+            let le_result = normalize_usize_le(value);
+            let be_result = normalize_usize_be(value);
+
+            // For non-zero values, LE and BE should be different
+            assert_ne!(
+                le_result, be_result,
+                "LE and BE should differ for value {value}"
+            );
+
+            // Both should be 8 bytes
+            assert_eq!(le_result.len(), 8);
+            assert_eq!(be_result.len(), 8);
+        }
+
+        // Zero should be the same in both endianness
+        assert_eq!(normalize_usize_le(0), normalize_usize_be(0));
+    }
+
+    #[test]
+    fn test_normalize_usize_roundtrip() {
+        // Test that we can reconstruct the original value from the normalized bytes
+        let test_values = vec![
+            0,
+            1,
+            255,
+            256,
+            65535,
+            65536,
+            4294967295,
+            4294967296,
+            usize::MAX,
+        ];
+
+        for &value in &test_values {
+            let le_bytes = normalize_usize_le(value);
+            let be_bytes = normalize_usize_be(value);
+
+            // Reconstruct from little-endian bytes
+            let reconstructed_le = usize::from_le_bytes(le_bytes);
+            assert_eq!(
+                reconstructed_le, value,
+                "LE roundtrip failed for value {value}"
+            );
+
+            // Reconstruct from big-endian bytes
+            let reconstructed_be = usize::from_be_bytes(be_bytes);
+            assert_eq!(
+                reconstructed_be, value,
+                "BE roundtrip failed for value {value}"
+            );
+        }
+    }
+
+    #[test]
+    fn test_normalize_usize_edge_cases() {
+        // Test edge cases and boundary values
+        let edge_cases = vec![
+            0,
+            1,
+            255,
+            256,
+            65535,
+            65536,
+            16777215,          // 2^24 - 1
+            16777216,          // 2^24
+            4294967295,        // 2^32 - 1
+            4294967296,        // 2^32
+            1099511627775,     // 2^40 - 1
+            1099511627776,     // 2^40
+            281474976710655,   // 2^48 - 1
+            281474976710656,   // 2^48
+            72057594037927935, // 2^56 - 1
+            72057594037927936, // 2^56
+            usize::MAX,
+        ];
+
+        for &value in &edge_cases {
+            let le_result = normalize_usize_le(value);
+            let be_result = normalize_usize_be(value);
+
+            // Both should be 8 bytes
+            assert_eq!(le_result.len(), 8);
+            assert_eq!(be_result.len(), 8);
+
+            // Roundtrip should work
+            assert_eq!(usize::from_le_bytes(le_result), value);
+            assert_eq!(usize::from_be_bytes(be_result), value);
+        }
+    }
+
+    #[test]
+    fn test_normalize_usize_architecture_independence() {
+        // Test that the functions work consistently regardless of the underlying architecture
+        // This test ensures that the functions provide consistent 8-byte output
+        // even on 32-bit systems where usize might be 4 bytes
+
+        let test_values = vec![0, 1, 255, 256, 65535, 65536, 4294967295, 4294967296];
+
+        for &value in &test_values {
+            let le_result = normalize_usize_le(value);
+            let be_result = normalize_usize_be(value);
+
+            // Always 8 bytes regardless of architecture
+            assert_eq!(le_result.len(), 8);
+            assert_eq!(be_result.len(), 8);
+
+            // The result should be consistent with the original value
+            assert_eq!(usize::from_le_bytes(le_result), value);
+            assert_eq!(usize::from_be_bytes(be_result), value);
+        }
+    }
+
+    #[test]
+    fn test_fr_serialization_roundtrip() {
+        let mut rng = thread_rng();
+
+        // Test multiple random Fr values
+        for _ in 0..10 {
+            let fr = Fr::rand(&mut rng);
+
+            // Test little-endian roundtrip
+            let le_bytes = fr_to_bytes_le(&fr);
+            let (reconstructed_le, _) = bytes_le_to_fr(&le_bytes).unwrap();
+            assert_eq!(fr, reconstructed_le);
+
+            // Test big-endian roundtrip
+            let be_bytes = fr_to_bytes_be(&fr);
+            let (reconstructed_be, _) = bytes_be_to_fr(&be_bytes).unwrap();
+            assert_eq!(fr, reconstructed_be);
+        }
+    }
+
+    #[test]
+    fn test_vec_fr_serialization_roundtrip() {
+        let mut rng = thread_rng();
+
+        // Test with different vector sizes
+        for size in [0, 1, 5, 10] {
+            let fr_vec: Vec<Fr> = (0..size).map(|_| Fr::rand(&mut rng)).collect();
+
+            // Test little-endian roundtrip
+            let le_bytes = vec_fr_to_bytes_le(&fr_vec);
+            let (reconstructed_le, _) = bytes_le_to_vec_fr(&le_bytes).unwrap();
+            assert_eq!(fr_vec, reconstructed_le);
+
+            // Test big-endian roundtrip
+            let be_bytes = vec_fr_to_bytes_be(&fr_vec);
+            let (reconstructed_be, _) = bytes_be_to_vec_fr(&be_bytes).unwrap();
+            assert_eq!(fr_vec, reconstructed_be);
+        }
+    }
+
+    #[test]
+    fn test_vec_u8_serialization_roundtrip() {
+        // Test with different vector sizes and content
+        let test_cases = vec![
+            vec![],
+            vec![0],
+            vec![255],
+            vec![1, 2, 3, 4, 5],
+            vec![0, 255, 128, 64, 32, 16, 8, 4, 2, 1],
+            (0..100).collect::<Vec<u8>>(),
+        ];
+
+        for test_case in test_cases {
+            // Test little-endian roundtrip
+            let le_bytes = vec_u8_to_bytes_le(&test_case);
+            let (reconstructed_le, _) = bytes_le_to_vec_u8(&le_bytes).unwrap();
+            assert_eq!(test_case, reconstructed_le);
+
+            // Test big-endian roundtrip
+            let be_bytes = vec_u8_to_bytes_be(&test_case);
+            let (reconstructed_be, _) = bytes_be_to_vec_u8(&be_bytes).unwrap();
+            assert_eq!(test_case, reconstructed_be);
+        }
+    }
+
+    #[test]
+    fn test_vec_usize_serialization_roundtrip() {
+        // Test with different vector sizes and content
+        let test_cases = vec![
+            vec![],
+            vec![0],
+            vec![usize::MAX],
+            vec![1, 2, 3, 4, 5],
+            vec![0, 255, 65535, 4294967295, usize::MAX],
+            (0..10).collect::<Vec<usize>>(),
+        ];
+
+        for test_case in test_cases {
+            // Test little-endian roundtrip
+            let le_bytes = {
+                let mut bytes = Vec::new();
+                bytes.extend_from_slice(&normalize_usize_le(test_case.len()));
+                for &value in &test_case {
+                    bytes.extend_from_slice(&normalize_usize_le(value));
+                }
+                bytes
+            };
+            let reconstructed_le = bytes_le_to_vec_usize(&le_bytes).unwrap();
+            assert_eq!(test_case, reconstructed_le);
+
+            // Test big-endian roundtrip
+            let be_bytes = {
+                let mut bytes = Vec::new();
+                bytes.extend_from_slice(&normalize_usize_be(test_case.len()));
+                for &value in &test_case {
+                    bytes.extend_from_slice(&normalize_usize_be(value));
+                }
+                bytes
+            };
+            let reconstructed_be = bytes_be_to_vec_usize(&be_bytes).unwrap();
+            assert_eq!(test_case, reconstructed_be);
+        }
+    }
+
+    #[test]
+    fn test_str_to_fr() {
+        // Test valid hex strings
+        let test_cases = vec![
+            ("0x0", 16, Fr::from(0u64)),
+            ("0x1", 16, Fr::from(1u64)),
+            ("0xff", 16, Fr::from(255u64)),
+            ("0x100", 16, Fr::from(256u64)),
+        ];
+
+        for (input, radix, expected) in test_cases {
+            let result = str_to_fr(input, radix).unwrap();
+            assert_eq!(result, expected);
+        }
+
+        // Test invalid inputs
+        assert!(str_to_fr("invalid", 16).is_err());
+        assert!(str_to_fr("0x", 16).is_err());
+    }
+
+    #[test]
+    fn test_endianness_differences() {
+        let mut rng = thread_rng();
+        let fr = Fr::rand(&mut rng);
+
+        // Test that LE and BE produce different byte representations
+        let le_bytes = fr_to_bytes_le(&fr);
+        let be_bytes = fr_to_bytes_be(&fr);
+
+        // They should be different (unless the value is symmetric)
+        if le_bytes != be_bytes {
+            // Verify they can both be reconstructed correctly
+            let (reconstructed_le, _) = bytes_le_to_fr(&le_bytes).unwrap();
+            let (reconstructed_be, _) = bytes_be_to_fr(&be_bytes).unwrap();
+            assert_eq!(fr, reconstructed_le);
+            assert_eq!(fr, reconstructed_be);
+        }
+    }
+
+    #[test]
+    fn test_error_handling() {
+        // Test bytes_le_to_fr and bytes_be_to_fr with insufficient data
+        let short_bytes = vec![0u8; 10]; // Less than FR_BYTE_SIZE (32 bytes)
+        assert!(bytes_le_to_fr(&short_bytes).is_err());
+        assert!(bytes_be_to_fr(&short_bytes).is_err());
+
+        // Test with empty bytes
+        let empty_bytes = vec![];
+        assert!(bytes_le_to_fr(&empty_bytes).is_err());
+        assert!(bytes_be_to_fr(&empty_bytes).is_err());
+
+        // Test with exact size - should succeed
+        let exact_bytes = vec![0u8; FR_BYTE_SIZE];
+        assert!(bytes_le_to_fr(&exact_bytes).is_ok());
+        assert!(bytes_be_to_fr(&exact_bytes).is_ok());
+
+        // Test with more than enough data - should succeed
+        let extra_bytes = vec![0u8; FR_BYTE_SIZE + 10];
+        assert!(bytes_le_to_fr(&extra_bytes).is_ok());
+        assert!(bytes_be_to_fr(&extra_bytes).is_ok());
+
+        // Test with valid length but insufficient data for vector deserialization
+        let valid_length_invalid_data = vec![0u8; 8]; // Length 0, but no data
+        assert!(bytes_le_to_vec_u8(&valid_length_invalid_data).is_ok());
+        assert!(bytes_be_to_vec_u8(&valid_length_invalid_data).is_ok());
+        assert!(bytes_le_to_vec_fr(&valid_length_invalid_data).is_ok());
+        assert!(bytes_be_to_vec_fr(&valid_length_invalid_data).is_ok());
+        assert!(bytes_le_to_vec_usize(&valid_length_invalid_data).is_ok());
+        assert!(bytes_be_to_vec_usize(&valid_length_invalid_data).is_ok());
+
+        // Test with reasonable length but insufficient data for vector deserialization
+        let reasonable_length = {
+            let mut bytes = vec![0u8; 8];
+            bytes[0] = 1; // Length 1
+            bytes
+        };
+        // This should fail because we don't have enough data for the vector elements
+        assert!(bytes_le_to_vec_u8(&reasonable_length).is_err());
+        assert!(bytes_be_to_vec_u8(&reasonable_length).is_err());
+        assert!(bytes_le_to_vec_fr(&reasonable_length).is_err());
+        assert!(bytes_be_to_vec_fr(&reasonable_length).is_err());
+        assert!(bytes_le_to_vec_usize(&reasonable_length).is_err());
+        assert!(bytes_be_to_vec_usize(&reasonable_length).is_err());
+
+        // Test with valid data for u8 vector
+        let valid_u8_data_le = {
+            let mut bytes = vec![0u8; 9];
+            bytes[..8].copy_from_slice(&(1u64.to_le_bytes())); // Length 1, little-endian
+            bytes[8] = 42; // One byte of data
+            bytes
+        };
+        let valid_u8_data_be = {
+            let mut bytes = vec![0u8; 9];
+            bytes[..8].copy_from_slice(&(1u64.to_be_bytes())); // Length 1, big-endian
+            bytes[8] = 42; // One byte of data
+            bytes
+        };
+        assert!(bytes_le_to_vec_u8(&valid_u8_data_le).is_ok());
+        assert!(bytes_be_to_vec_u8(&valid_u8_data_be).is_ok());
+    }
+
+    #[test]
+    fn test_empty_vectors() {
+        // Test empty vector serialization/deserialization
+        let empty_fr: Vec<Fr> = vec![];
+        let empty_u8: Vec<u8> = vec![];
+        let empty_usize: Vec<usize> = vec![];
+
+        // Test Fr vectors
+        let le_fr_bytes = vec_fr_to_bytes_le(&empty_fr);
+        let be_fr_bytes = vec_fr_to_bytes_be(&empty_fr);
+        let (reconstructed_le_fr, _) = bytes_le_to_vec_fr(&le_fr_bytes).unwrap();
+        let (reconstructed_be_fr, _) = bytes_be_to_vec_fr(&be_fr_bytes).unwrap();
+        assert_eq!(empty_fr, reconstructed_le_fr);
+        assert_eq!(empty_fr, reconstructed_be_fr);
+
+        // Test u8 vectors
+        let le_u8_bytes = vec_u8_to_bytes_le(&empty_u8);
+        let be_u8_bytes = vec_u8_to_bytes_be(&empty_u8);
+        let (reconstructed_le_u8, _) = bytes_le_to_vec_u8(&le_u8_bytes).unwrap();
+        let (reconstructed_be_u8, _) = bytes_be_to_vec_u8(&be_u8_bytes).unwrap();
+        assert_eq!(empty_u8, reconstructed_le_u8);
+        assert_eq!(empty_u8, reconstructed_be_u8);
+
+        // Test usize vectors
+        let le_usize_bytes = {
+            let mut bytes = Vec::new();
+            bytes.extend_from_slice(&normalize_usize_le(0));
+            bytes
+        };
+        let be_usize_bytes = {
+            let mut bytes = Vec::new();
+            bytes.extend_from_slice(&normalize_usize_be(0));
+            bytes
+        };
+        let reconstructed_le_usize = bytes_le_to_vec_usize(&le_usize_bytes).unwrap();
+        let reconstructed_be_usize = bytes_be_to_vec_usize(&be_usize_bytes).unwrap();
+        assert_eq!(empty_usize, reconstructed_le_usize);
+        assert_eq!(empty_usize, reconstructed_be_usize);
+    }
+}

rustfmt.toml

@@ -0,0 +1,6 @@
+# Run cargo +nightly fmt to format with this configuration
+edition = "2021"                    # use Rust 2021 edition
+unstable_features = true            # needed for group_imports
+reorder_imports = true              # sort imports alphabetically
+imports_granularity = "Crate"       # keep items from the same crate grouped together
+group_imports = "StdExternalCrate"  # group std, external, and local imports separately

utils/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "zerokit_utils"
-version = "0.5.2"
+version = "1.0.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Various utilities for Zerokit"
@@ -12,28 +12,25 @@ repository = "https://github.com/vacp2p/zerokit"
 bench = false
 
 [dependencies]
-ark-ff = { version = "0.5.0", default-features = false, features = [
-    "parallel",
-] }
-num-bigint = { version = "0.4.6", default-features = false, features = [
-    "rand",
-] }
-color-eyre = "0.6.3"
-pmtree = { package = "vacp2p_pmtree", version = "2.0.2", optional = true }
+ark-ff = { version = "0.5.0", default-features = false }
+num-bigint = { version = "0.4.6", default-features = false }
+pmtree = { package = "vacp2p_pmtree", version = "2.0.3", optional = true }
 sled = "0.34.7"
-serde = "1.0"
-lazy_static = "1.5.0"
-hex = "0.4"
+serde_json = "1.0.145"
+rayon = "1.11.0"
+thiserror = "2.0"
 
 [dev-dependencies]
+hex = "0.4.3"
+hex-literal = "1.1.0"
 ark-bn254 = { version = "0.5.0", features = ["std"] }
 num-traits = "0.2.19"
-hex-literal = "1.0.0"
 tiny-keccak = { version = "2.0.2", features = ["keccak"] }
-criterion = { version = "0.4.0", features = ["html_reports"] }
+criterion = { version = "0.8.0", features = ["html_reports"] }
 
 [features]
 default = []
+parallel = ["ark-ff/parallel"]
 pmtree-ft = ["pmtree"]
 
 [[bench]]
@@ -43,3 +40,6 @@ harness = false
 [[bench]]
 name = "poseidon_benchmark"
 harness = false
+
+[package.metadata.docs.rs]
+all-features = true

utils/Makefile.toml

@@ -4,7 +4,7 @@ args = ["build", "--release"]
 
 [tasks.test]
 command = "cargo"
-args = ["test", "--release"]
+args = ["test", "--release", "--", "--nocapture"]
 
 [tasks.bench]
 command = "cargo"

utils/README.md

@@ -1,39 +1,45 @@
 # Zerokit Utils Crate
 
 [![Crates.io](https://img.shields.io/crates/v/zerokit_utils.svg)](https://crates.io/crates/zerokit_utils)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 
-Cryptographic primitives for zero-knowledge applications, featuring efficient Merkle tree implementations and a Poseidon hash function.
+**Zerokit Utils** provides essential cryptographic primitives optimized for zero-knowledge applications.
+This crate features efficient Merkle tree implementations and a Poseidon hash function,
+designed to be robust and performant.
 
 ## Overview
 
 This crate provides core cryptographic components optimized for zero-knowledge proof systems:
 
-1. Multiple Merkle tree implementations with different space/time tradeoffs
-2. A Poseidon hash implementation
+- **Multiple Merkle Trees**: Various implementations optimised for the trade-off between space and time.
+- **Poseidon Hash Function**: An efficient hashing algorithm suitable for ZK contexts, with customizable parameters.
+- **Parallel Performance**: Leverages Rayon for significant speed-ups in Merkle tree computations.
+- **Arkworks Compatibility**: Poseidon hash implementation is designed to work seamlessly
+  with Arkworks field traits and data structures.
 
 ## Merkle Tree Implementations
 
-The crate supports two interchangeable Merkle tree implementations:
+Merkle trees are fundamental data structures for verifying data integrity and set membership.
+Zerokit Utils offers two interchangeable implementations:
 
-- **FullMerkleTree**
-  - Stores each tree node in memory
-- **OptimalMerkleTree**
-  - Only stores nodes used to prove accumulation of set leaves
+### Understanding Merkle Tree Terminology
 
-### Implementation notes
+To better understand the structure and parameters of our Merkle trees, here's a quick glossary:
 
-Glossary:
+- **Depth (`depth`)**: level of leaves if we count from root.
+  If the root is at level 0, leaves are at level `depth`.
+- **Number of Levels**: `depth + 1`.
+- **Capacity (Number of Leaves)**: $2^{\text{depth}}$. This is the maximum number of leaves the tree can hold.
+- **Total Number of Nodes**: $2^{(\text{depth} + 1)} - 1$ for a full binary tree.
 
-* depth: level of leaves if we count from levels from 0
-* number of levels: depth + 1
-* capacity (== number of leaves) -- 1 << depth
-* total number of nodes: 1 << (depth + 1)) - 1
+**Example for a tree with `depth: 3`**:
 
-So for instance:
-* depth: 3
-* number of levels: 4
-* capacity (number of leaves): 8
-* total number of nodes: 15
+- Number of Levels: 4 (levels 0, 1, 2, 3)
+- Capacity (Number of Leaves): $2^3 = 8$
+- Total Number of Nodes: $2^{(3+1)} - 1 = 15$
+
+Visual representation of a Merkle tree with `depth: 3`:
 
 ```mermaid
 flowchart TD
@@ -53,39 +59,55 @@ flowchart TD
     N6 -->|Leaf| L8
 ```
 
+### Available Implementations
+
+- **FullMerkleTree**
+  - Stores all tree nodes in memory.
+  - Use Case: Use when memory is abundant and operation speed is critical.
+
+- **OptimalMerkleTree**
+  - Stores only the nodes required to prove the accumulation of set leaves (i.e., authentication paths).
+  - Use Case: Suited for environments where memory efficiency is a higher priority than raw speed.
+
+#### Parallel Processing with Rayon
+
+Both `OptimalMerkleTree` and `FullMerkleTree` internally utilize the Rayon crate
+to accelerate computations through data parallelism.
+This can lead to significant performance improvements, particularly during updates to large Merkle trees.
 
 ## Poseidon Hash Implementation
 
-This crate provides an implementation to compute the Poseidon hash round constants and MDS matrices:
+This crate provides an implementation for computing Poseidon hash round constants and MDS matrices.
+Key characteristics include:
 
-- **Customizable parameters**: Supports different security levels and input sizes
-- **Arkworks-friendly**: Adapted to work over arkworks field traits and custom data structures
+- **Customizable parameters**: Supports various security levels and input sizes,
+  allowing you to tailor the hash function to your specific needs.
+- **Arkworks-friendly**: Adapted to integrate smoothly with Arkworks field traits and custom data structures.
 
-### Security Note
+### ⚠️ Security Note
 
-The MDS matrices are generated iteratively using the Grain LFSR until certain criteria are met.
-According to the paper, such matrices must respect specific conditions which are checked by 3 different algorithms in the reference implementation.
+The MDS matrices used in the Poseidon hash function are generated iteratively
+using the Grain LFSR (Linear Feedback Shift Register) algorithm until specific cryptographic criteria are met.
 
-These validation algorithms are not currently implemented in this crate.
-For the hardcoded parameters, the first random matrix generated satisfies these conditions.
-If using different parameters, you should check against the reference implementation how many matrices are generated before outputting the correct one,
-and pass this number to the `skip_matrices` parameter of the `find_poseidon_ark_and_mds` function.
+- The reference Poseidon implementation includes validation algorithms to ensure these criteria are satisfied.
+  These validation algorithms are not currently implemented in this crate.
+- For the hardcoded parameters provided within this crate,
+  the initially generated random matrix has been verified to meet these conditions.
+- If you intend to use custom parameters, it is crucial to verify your generated MDS matrix.
+  You should consult the Poseidon reference implementation to determine
+  how many matrices are typically skipped before a valid one is found.
+  This count should then be passed as the `skip_matrices parameter` to the `find_poseidon_ark_and_mds`
+  function in this crate.
 
 ## Installation
 
-Add Zerokit Utils to your Rust project:
+Add zerokit-utils as a dependency to your Cargo.toml file:
 
 ```toml
 [dependencies]
-zerokit-utils = "0.5.1"
+zerokit-utils = "1.0.0"
 ```
 
-## Performance Considerations
-
-- **FullMerkleTree**: Use when memory is abundant and operation speed is critical
-- **OptimalMerkleTree**: Use when memory efficiency is more important than raw speed
-- **Poseidon**: Offers a good balance between security and performance for ZK applications
-
 ## Building and Testing
 
 ```bash

utils/benches/merkle_tree_benchmark.rs

@@ -1,11 +1,13 @@
+use std::{fmt::Display, str::FromStr, sync::LazyLock};
+
 use criterion::{criterion_group, criterion_main, Criterion};
-use hex_literal::hex;
-use lazy_static::lazy_static;
-use std::{fmt::Display, str::FromStr};
 use tiny_keccak::{Hasher as _, Keccak};
 use zerokit_utils::{
+    error::HashError,
+    merkle_tree::{
         FullMerkleConfig, FullMerkleTree, Hasher, OptimalMerkleConfig, OptimalMerkleTree,
         ZerokitMerkleTree,
+    },
 };
 
 #[derive(Clone, Copy, Eq, PartialEq)]
@@ -16,19 +18,20 @@ struct TestFr([u8; 32]);
 
 impl Hasher for Keccak256 {
     type Fr = TestFr;
+    type Error = HashError;
 
     fn default_leaf() -> Self::Fr {
         TestFr([0; 32])
     }
 
-    fn hash(inputs: &[Self::Fr]) -> Self::Fr {
+    fn hash(inputs: &[Self::Fr]) -> Result<Self::Fr, HashError> {
         let mut output = [0; 32];
         let mut hasher = Keccak::v256();
         for element in inputs {
             hasher.update(element.0.as_slice());
         }
         hasher.finalize(&mut output);
-        TestFr(output)
+        Ok(TestFr(output))
     }
 }
 
@@ -46,56 +49,78 @@ impl FromStr for TestFr {
     }
 }
 
-lazy_static! {
-    static ref LEAVES: [TestFr; 4] = [
-        hex!("0000000000000000000000000000000000000000000000000000000000000001"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000002"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000003"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-    ]
-    .map(TestFr);
-}
+static LEAVES: LazyLock<Vec<TestFr>> = LazyLock::new(|| {
+    let mut leaves = Vec::with_capacity(1 << 20);
+    for i in 0..(1 << 20) {
+        let mut bytes = [0u8; 32];
+        bytes[28..].copy_from_slice(&(i as u32).to_be_bytes());
+        leaves.push(TestFr(bytes));
+    }
+    leaves
+});
+
+static INDICES: LazyLock<Vec<usize>> = LazyLock::new(|| (0..(1 << 20)).collect());
+
+const NOF_LEAVES: usize = 8192;
 
 pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
     let mut tree =
-        OptimalMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), OptimalMerkleConfig::default())
+        OptimalMerkleTree::<Keccak256>::new(20, TestFr([0; 32]), OptimalMerkleConfig::default())
             .unwrap();
 
+    for i in 0..NOF_LEAVES {
+        tree.set(i, LEAVES[i % LEAVES.len()]).unwrap();
+    }
+
     c.bench_function("OptimalMerkleTree::set", |b| {
+        let mut index = NOF_LEAVES;
         b.iter(|| {
-            tree.set(0, LEAVES[0]).unwrap();
+            tree.set(index % (1 << 20), LEAVES[index % LEAVES.len()])
+                .unwrap();
+            index = (index + 1) % (1 << 20);
         })
     });
 
     c.bench_function("OptimalMerkleTree::delete", |b| {
+        let mut index = 0;
         b.iter(|| {
-            tree.delete(0).unwrap();
+            tree.delete(index % NOF_LEAVES).unwrap();
+            tree.set(index % NOF_LEAVES, LEAVES[index % LEAVES.len()])
+                .unwrap();
+            index = (index + 1) % NOF_LEAVES;
         })
     });
 
     c.bench_function("OptimalMerkleTree::override_range", |b| {
+        let mut offset = 0;
         b.iter(|| {
-            tree.override_range(0, LEAVES.into_iter(), [0, 1, 2, 3].into_iter())
+            let range = offset..offset + NOF_LEAVES;
+            tree.override_range(
+                offset,
+                LEAVES[range.clone()].iter().cloned(),
+                INDICES[range.clone()].iter().cloned(),
+            )
             .unwrap();
-        })
-    });
-
-    c.bench_function("OptimalMerkleTree::compute_root", |b| {
-        b.iter(|| {
-            tree.compute_root().unwrap();
+            offset = (offset + NOF_LEAVES) % (1 << 20);
         })
     });
 
     c.bench_function("OptimalMerkleTree::get", |b| {
+        let mut index = 0;
         b.iter(|| {
-            tree.get(0).unwrap();
+            tree.get(index % NOF_LEAVES).unwrap();
+            index = (index + 1) % NOF_LEAVES;
         })
     });
 
-    // check intermediate node getter which required additional computation of sub root index
     c.bench_function("OptimalMerkleTree::get_subtree_root", |b| {
+        let mut level = 1;
+        let mut index = 0;
         b.iter(|| {
-            tree.get_subtree_root(1, 0).unwrap();
+            tree.get_subtree_root(level % 20, index % (1 << (20 - (level % 20))))
+                .unwrap();
+            index = (index + 1) % (1 << (20 - (level % 20)));
+            level = 1 + (level % 20);
         })
     });
 
@@ -108,43 +133,61 @@ pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
 
 pub fn full_merkle_tree_benchmark(c: &mut Criterion) {
     let mut tree =
-        FullMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), FullMerkleConfig::default()).unwrap();
+        FullMerkleTree::<Keccak256>::new(20, TestFr([0; 32]), FullMerkleConfig::default()).unwrap();
+
+    for i in 0..NOF_LEAVES {
+        tree.set(i, LEAVES[i % LEAVES.len()]).unwrap();
+    }
 
     c.bench_function("FullMerkleTree::set", |b| {
+        let mut index = NOF_LEAVES;
         b.iter(|| {
-            tree.set(0, LEAVES[0]).unwrap();
+            tree.set(index % (1 << 20), LEAVES[index % LEAVES.len()])
+                .unwrap();
+            index = (index + 1) % (1 << 20);
         })
     });
 
     c.bench_function("FullMerkleTree::delete", |b| {
+        let mut index = 0;
         b.iter(|| {
-            tree.delete(0).unwrap();
+            tree.delete(index % NOF_LEAVES).unwrap();
+            tree.set(index % NOF_LEAVES, LEAVES[index % LEAVES.len()])
+                .unwrap();
+            index = (index + 1) % NOF_LEAVES;
         })
     });
 
     c.bench_function("FullMerkleTree::override_range", |b| {
+        let mut offset = 0;
         b.iter(|| {
-            tree.override_range(0, LEAVES.into_iter(), [0, 1, 2, 3].into_iter())
+            let range = offset..offset + NOF_LEAVES;
+            tree.override_range(
+                offset,
+                LEAVES[range.clone()].iter().cloned(),
+                INDICES[range.clone()].iter().cloned(),
+            )
             .unwrap();
-        })
-    });
-
-    c.bench_function("FullMerkleTree::compute_root", |b| {
-        b.iter(|| {
-            tree.compute_root().unwrap();
+            offset = (offset + NOF_LEAVES) % (1 << 20);
         })
     });
 
     c.bench_function("FullMerkleTree::get", |b| {
+        let mut index = 0;
         b.iter(|| {
-            tree.get(0).unwrap();
+            tree.get(index % NOF_LEAVES).unwrap();
+            index = (index + 1) % NOF_LEAVES;
         })
     });
 
-    // check intermediate node getter which required additional computation of sub root index
     c.bench_function("FullMerkleTree::get_subtree_root", |b| {
+        let mut level = 1;
+        let mut index = 0;
         b.iter(|| {
-            tree.get_subtree_root(1, 0).unwrap();
+            tree.get_subtree_root(level % 20, index % (1 << (20 - (level % 20))))
+                .unwrap();
+            index = (index + 1) % (1 << (20 - (level % 20)));
+            level = 1 + (level % 20);
         })
     });
 

utils/benches/poseidon_benchmark.rs

@@ -1,8 +1,8 @@
+use std::hint::black_box;
+
 use ark_bn254::Fr;
-use criterion::{
-    black_box, criterion_group, criterion_main, BatchSize, BenchmarkId, Criterion, Throughput,
-};
-use zerokit_utils::Poseidon;
+use criterion::{criterion_group, criterion_main, BatchSize, BenchmarkId, Criterion, Throughput};
+use zerokit_utils::poseidon::Poseidon;
 
 const ROUND_PARAMS: [(usize, usize, usize, usize); 8] = [
     (2, 8, 56, 0),

utils/src/error.rs

@@ -0,0 +1,11 @@
+use super::poseidon::error::PoseidonError;
+pub use crate::merkle_tree::{FromConfigError, ZerokitMerkleTreeError};
+
+/// Errors that can occur during hashing operations.
+#[derive(Debug, thiserror::Error)]
+pub enum HashError {
+    #[error("Poseidon hash error: {0}")]
+    Poseidon(#[from] PoseidonError),
+    #[error("Generic hash error: {0}")]
+    Generic(String),
+}