refactor: update tree depth to 30 and adjust resource paths accordingly

I had been trying to consume zerokit (specifically rln on x86_64), to
build libwaku (nwaku) and was having issues, this PR at least allows a
build to occur.

```bash
$ nix flake show github:vacp2p/zerokit
error: syntax error, unexpected '=', expecting ';'
       at «github:vacp2p/zerokit/0b00c639a059a2cfde74bcf68fdf75db3b6898a4»/flake.nix:36:25:
           35|
           36|         rln-linux-arm64 = buildRln {
             |                         ^
           37|           target-platform = "aarch64-multiplatform";
```

`Cargo.lock` is required in repo for this to be possible, otherwise:
```bash
$ nix build .#rln --show-trace
warning: Git tree '/home/j/experiments/zerokit' is dirty
error:
       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:37:12:
           36|
           37|   strict = derivationStrict drvAttrs;
             |            ^
           38|

       … while evaluating derivation 'zerokit-nightly'
         whose name attribute is located at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/stdenv/generic/make-derivation.nix:336:7

       … while evaluating attribute 'cargoDeps' of derivation 'zerokit-nightly'
         at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/build-support/rust/build-rust-package/default.nix:157:5:
          156|   // {
          157|     cargoDeps = cargoDeps';
             |     ^
          158|     inherit buildAndTestSubdir;

       … while calling the 'getAttr' builtin
         at <nix/derivation-internal.nix>:50:17:
           49|     value = commonAttrs // {
           50|       outPath = builtins.getAttr outputName strict;
             |                 ^
           51|       drvPath = strict.drvPath;

       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:37:12:
           36|
           37|   strict = derivationStrict drvAttrs;
             |            ^
           38|

       … while evaluating derivation 'cargo-vendor-dir'
         whose name attribute is located at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/stdenv/generic/make-derivation.nix:336:7

       … while evaluating attribute 'buildCommand' of derivation 'cargo-vendor-dir'
         at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/build-support/trivial-builders/default.nix:59:17:
           58|         enableParallelBuilding = true;
           59|         inherit buildCommand name;
             |                 ^
           60|         passAsFile = [ "buildCommand" ]

       … while calling the 'toString' builtin
         at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/build-support/rust/import-cargo-lock.nix:264:20:
          263|
          264|     for crate in ${toString depCrates}; do
             |                    ^
          265|       # Link the crate directory, removing the output path hash from the destination.

       … while calling the 'deepSeq' builtin
         at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/build-support/rust/import-cargo-lock.nix:68:15:
           67|   # being evaluated otherwise, since there could be no git dependencies.
           68|   depCrates = builtins.deepSeq gitShaOutputHash (builtins.map mkCrate depPackages);
             |               ^
           69|

       … while calling the 'map' builtin
         at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/build-support/rust/import-cargo-lock.nix:68:50:
           67|   # being evaluated otherwise, since there could be no git dependencies.
           68|   depCrates = builtins.deepSeq gitShaOutputHash (builtins.map mkCrate depPackages);
             |                                                  ^
           69|

       … while calling the 'filter' builtin
         at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/build-support/rust/import-cargo-lock.nix:61:17:
           60|   # safely skip it.
           61|   depPackages = builtins.filter (p: p ? "source") packages;
             |                 ^
           62|

       … while calling the 'fromTOML' builtin
         at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/build-support/rust/import-cargo-lock.nix:50:20:
           49|
           50|   parsedLockFile = builtins.fromTOML lockFileContents;
             |                    ^
           51|

       … while evaluating the argument passed to builtins.fromTOML

       … while calling the 'readFile' builtin
         at /nix/store/fy7zcm8ya6p215wvrlqrl8022da6asn0-source/pkgs/build-support/rust/import-cargo-lock.nix:47:10:
           46|     if lockFile != null
           47|     then builtins.readFile lockFile
             |          ^
           48|     else args.lockFileContents;

       error: opening file '/nix/store/qh8gf0sl8znhnjwc1ksif7pwik26dsyd-source/Cargo.lock': No such file or directory
```

The PR allows for a successful build:
```bash
$ ls -R result
result:
target

result/target:
release

result/target/release:
librln.a  librln.d  librln.rlib  librln.so
```

---------

Co-authored-by: Jarrad Hope <jarrad@logos.co>
Co-authored-by: Vinh Trịnh <108657096+vinhtc27@users.noreply.github.com>

.github/labels.yml

@@ -90,11 +90,6 @@
   description: go-waku-productionization track (Waku Product)
   color: 9DEA79
 
-# Tracks within zk-WASM project
-- name: track:kickoff
-  description: Kickoff track (zk-WASM)
-  color: 06B6C8
-
 # Tracks within RAD project
 - name: track:waku-specs
   description: Waku specs track (RAD)

.github/workflows/ci.yml

@@ -2,44 +2,233 @@ on:
   push:
     branches:
       - master
+    paths-ignore:
+      - "**.md"
+      - "!.github/workflows/*.yml"
+      - "!rln-wasm/**"
+      - "!rln/src/**"
+      - "!rln/resources/**"
+      - "!utils/src/**"
+      - "!rln-wasm-utils/**"
   pull_request:
+    types: [opened, synchronize, reopened, ready_for_review]
+    paths-ignore:
+      - "**.md"
+      - "!.github/workflows/*.yml"
+      - "!rln-wasm/**"
+      - "!rln/src/**"
+      - "!rln/resources/**"
+      - "!utils/src/**"
+      - "!rln-wasm-utils/**"
 
-name: Tests
+name: CI
 
 jobs:
-  tests:
-    runs-on: ubuntu-latest
+  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]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: Test - ${{ matrix.crate }} - ${{ matrix.platform }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-      - name: Update git submodules
-        run: git submodule update --init --recursive
-      - name: cargo test
+        uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - name: Test utils
         run: |
-            cargo test
-  lint:
-    runs-on: ubuntu-latest
+          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", "stateless"]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: Test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
     steps:
       - name: Checkout sources
-        uses: actions/checkout@v2
+        uses: actions/checkout@v4
       - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
+        uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - name: Test rln
+        run: |
+          if [ ${{ matrix.feature }} == default ]; then
+            cargo make test --release
+          else
+            cargo make test_${{ matrix.feature }} --release
+          fi
+        working-directory: ${{ matrix.crate }}
+
+  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]
+        crate: [rln-wasm]
+        feature: ["default"]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: Test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install stable toolchain
+        uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - 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 }}
+
+  rln-wasm-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: [rln-wasm-utils]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: Test - ${{ matrix.crate }} - ${{ matrix.platform }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: Install stable toolchain
+        uses: dtolnay/rust-toolchain@stable
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - name: Test rln-wasm-utils
+        run: cargo make test --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, rln-wasm-utils, utils]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: Lint - ${{ matrix.crate }} - ${{ matrix.platform }}
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - name: Install stable toolchain
+        uses: dtolnay/rust-toolchain@stable
         with:
-          profile: minimal
-          toolchain: stable
-          override: true
           components: rustfmt, clippy
-      - name: Update git submodules
-        run: git submodule update --init --recursive
-      - name: cargo fmt
-        run: cargo fmt --all -- --check
-      - name: cargo clippy
-        run: cargo clippy
-        # Currently not treating warnings as error, too noisy
-        # -- -D warnings
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - name: Check formatting
+        if: success() || failure()
+        run: cargo fmt -- --check
+        working-directory: ${{ matrix.crate }}
+      - name: Check clippy
+        if: success() || failure()
+        run: |
+          cargo clippy --all-targets --release -- -D warnings
+        working-directory: ${{ matrix.crate }}
+
+  benchmark-utils:
+    # run only on ready pull requests
+    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]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: Benchmark - ${{ matrix.crate }} - ${{ matrix.platform }}
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - uses: Swatinem/rust-cache@v2
+      - uses: boa-dev/criterion-compare-action@v3
+        with:
+          branchName: ${{ github.base_ref }}
+          cwd: ${{ matrix.crate }}
+
+  benchmark-rln:
+    # run only on ready pull requests
+    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"]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: Benchmark - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - uses: Swatinem/rust-cache@v2
+      - uses: boa-dev/criterion-compare-action@v3
+        with:
+          branchName: ${{ github.base_ref }}
+          cwd: ${{ matrix.crate }}
+          features: ${{ matrix.feature }}

.github/workflows/nightly-release.yml

@@ -0,0 +1,225 @@
+name: Nightly build
+on:
+  schedule:
+    - cron: "0 0 * * *"
+  workflow_dispatch:
+
+jobs:
+  linux:
+    name: Linux build
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        feature:
+          - "stateless"
+          - "stateless,parallel"
+          - "pmtree-ft"
+          - "pmtree-ft,parallel"
+          - "fullmerkletree"
+          - "fullmerkletree,parallel"
+          - "optimalmerkletree"
+          - "optimalmerkletree,parallel"
+        target:
+          - x86_64-unknown-linux-gnu
+          - aarch64-unknown-linux-gnu
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - name: Install stable toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          target: ${{ matrix.target }}
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - name: Cross build
+        run: |
+          cross build --release --target ${{ matrix.target }} --no-default-features --features ${{ matrix.feature }} --workspace
+          mkdir release
+          cp target/${{ matrix.target }}/release/librln* release/
+          tar -czvf ${{ matrix.target }}-${{ matrix.feature }}-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
+          retention-days: 2
+
+  macos:
+    name: MacOS build
+    runs-on: macos-latest
+    strategy:
+      matrix:
+        feature:
+          - "stateless"
+          - "stateless,parallel"
+          - "pmtree-ft"
+          - "pmtree-ft,parallel"
+          - "fullmerkletree"
+          - "fullmerkletree,parallel"
+          - "optimalmerkletree"
+          - "optimalmerkletree,parallel"
+        target:
+          - x86_64-apple-darwin
+          - aarch64-apple-darwin
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - name: Install stable toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          target: ${{ matrix.target }}
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - name: Cross build
+        run: |
+          cross build --release --target ${{ matrix.target }} --no-default-features --features ${{ matrix.feature }} --workspace
+          mkdir release
+          cp target/${{ matrix.target }}/release/librln* release/
+          tar -czvf ${{ matrix.target }}-${{ matrix.feature }}-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
+          retention-days: 2
+
+  rln-wasm:
+    name: Build rln-wasm
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        feature:
+          - "default"
+          - "parallel"
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - name: Install stable toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32-unknown-unknown
+      - name: Install nightly toolchain
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          targets: wasm32-unknown-unknown
+          components: rust-src
+      - uses: Swatinem/rust-cache@v2
+        with:
+          key: rln-wasm-${{ matrix.feature }}
+      - name: Install dependencies
+        run: make installdeps
+      - name: Install wasm-pack
+        run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
+      - name: Install binaryen
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y binaryen
+      - name: Build rln-wasm package
+        run: |
+          if [[ ${{ matrix.feature }} == *parallel* ]]; then
+            env RUSTFLAGS="-C target-feature=+atomics,+bulk-memory,+mutable-globals" \
+            rustup run nightly wasm-pack build --release --target web --scope waku \
+            --features ${{ matrix.feature }} -Z build-std=panic_abort,std
+          else
+            wasm-pack build --release --target web --scope waku
+          fi
+
+          sed -i.bak 's/rln-wasm/zerokit-rln-wasm/g' pkg/package.json && rm pkg/package.json.bak
+
+          wasm-opt pkg/rln_wasm_bg.wasm -Oz --strip-debug --strip-dwarf \
+          --remove-unused-module-elements --vacuum -o pkg/rln_wasm_bg.wasm
+
+          mkdir release
+          cp -r pkg/* release/
+          tar -czvf rln-wasm-${{ matrix.feature }}.tar.gz release/
+        working-directory: rln-wasm
+      - name: Upload archive artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: rln-wasm-${{ matrix.feature }}-archive
+          path: rln-wasm/rln-wasm-${{ matrix.feature }}.tar.gz
+          retention-days: 2
+
+  rln-wasm-utils:
+    name: Build rln-wasm-utils
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - name: Install stable toolchain
+        uses: dtolnay/rust-toolchain@stable
+        with:
+          targets: wasm32-unknown-unknown
+      - name: Install nightly toolchain
+        uses: dtolnay/rust-toolchain@nightly
+        with:
+          targets: wasm32-unknown-unknown
+          components: rust-src
+      - uses: Swatinem/rust-cache@v2
+        with:
+          key: rln-wasm-utils
+      - name: Install dependencies
+        run: make installdeps
+      - name: Install wasm-pack
+        run: curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
+      - name: Install binaryen
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y binaryen
+      - name: Build rln-wasm-utils package
+        run: |
+          wasm-pack build --release --target web --scope waku
+
+          sed -i.bak 's/rln-wasm-utils/zerokit-rln-wasm-utils/g' pkg/package.json && rm pkg/package.json.bak
+
+          wasm-opt pkg/rln_wasm_utils_bg.wasm -Oz --strip-debug --strip-dwarf \
+          --remove-unused-module-elements --vacuum -o pkg/rln_wasm_utils_bg.wasm
+
+          mkdir release
+          cp -r pkg/* release/
+          tar -czvf rln-wasm-utils.tar.gz release/
+        working-directory: rln-wasm-utils
+      - name: Upload archive artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: rln-wasm-utils-archive
+          path: rln-wasm-utils/rln-wasm-utils.tar.gz
+          retention-days: 2
+
+  prepare-prerelease:
+    name: Prepare pre-release
+    needs: [linux, macos, rln-wasm, rln-wasm-utils]
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        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:
+          delete_release: true
+          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')
+          gh release create nightly --prerelease --target master \
+            --title 'Nightly build ("master" branch)' \
+            --generate-notes \
+            --draft=false \
+            --notes-start-tag $start_tag \
+            *-archive/*.tar.gz \
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Delete artifacts
+        uses: geekyeggo/delete-artifact@v5
+        with:
+          failOnError: false
+          name: |
+            *-archive

.github/workflows/sync-labels.yml

@@ -9,7 +9,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v4
       - uses: micnncim/action-label-syncer@v1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.gitignore

@@ -1,16 +1,17 @@
+# Common files to ignore in Rust projects
 .DS_Store
 .idea
 *.log
 tmp/
 
-# Generated by Cargo
-# will have compiled files and executables
-debug/
-target/
+# Generated by Cargo will have compiled files and executables
+/target
 
-# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
-# More information here https://doc.rust-lang.org/cargo/guide/cargo-toml-vs-cargo-lock.html
-Cargo.lock
+# Generated by rln-cli
+rln-cli/database
+
+# Generated by Nix
+result
 
 # These are backup files generated by rustfmt
 **/*.rs.bk

.gitmodules

@@ -1,8 +0,0 @@
-[submodule "rln/vendor/rln"]
-	path = rln/vendor/rln
-	ignore = dirty
-	url = https://github.com/Rate-Limiting-Nullifier/rln_circuits
-[submodule "semaphore/vendor/semaphore"]
-	path = semaphore/vendor/semaphore
-	ignore = dirty
-	url = https://github.com/appliedzkp/semaphore.git

CHANGELOG.md

@@ -0,0 +1,29 @@
+# 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 +1,205 @@
+# 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
+```
+
+Choose the appropriate test commands based on your changes:
+
+- Core RLN changes: `make test`
+- Stateless features: `cargo make test_stateless`
+- WASM/browser features: `cargo make test_browser`
+- Parallel computation: `cargo make test_parallel`
+
+### 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
+- `rln-wasm-utils` - WebAssembly utilities
+- `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

@@ -1,6 +1,10 @@
 [workspace]
-members = [
-  "multiplier",
-  "semaphore",
-  "rln",
-]
+members = ["rln", "utils"]
+exclude = ["rln-cli", "rln-wasm", "rln-wasm-utils"]
+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.
+[profile.dev.package."*"]
+opt-level = 3

Cross.toml

@@ -0,0 +1,35 @@
+[target.x86_64-pc-windows-gnu]
+image = "ghcr.io/cross-rs/x86_64-pc-windows-gnu:latest"
+
+[target.aarch64-unknown-linux-gnu]
+image = "ghcr.io/cross-rs/aarch64-unknown-linux-gnu:latest"
+
+[target.x86_64-unknown-linux-gnu]
+image = "ghcr.io/cross-rs/x86_64-unknown-linux-gnu:latest"
+
+[target.arm-unknown-linux-gnueabi]
+image = "ghcr.io/cross-rs/arm-unknown-linux-gnueabi:latest"
+
+[target.i686-pc-windows-gnu]
+image = "ghcr.io/cross-rs/i686-pc-windows-gnu:latest"
+
+[target.i686-unknown-linux-gnu]
+image = "ghcr.io/cross-rs/i686-unknown-linux-gnu:latest"
+
+[target.arm-unknown-linux-gnueabihf]
+image = "ghcr.io/cross-rs/arm-unknown-linux-gnueabihf:latest"
+
+[target.mips-unknown-linux-gnu]
+image = "ghcr.io/cross-rs/mips-unknown-linux-gnu:latest"
+
+[target.mips64-unknown-linux-gnuabi64]
+image = "ghcr.io/cross-rs/mips64-unknown-linux-gnuabi64:latest"
+
+[target.mips64el-unknown-linux-gnuabi64]
+image = "ghcr.io/cross-rs/mips64el-unknown-linux-gnuabi64:latest"
+
+[target.mipsel-unknown-linux-gnu]
+image = "ghcr.io/cross-rs/mipsel-unknown-linux-gnu:latest"
+
+[target.aarch64-linux-android]
+image = "ghcr.io/cross-rs/aarch64-linux-android:edge"

LICENSE-APACHE

@@ -0,0 +1,203 @@
+Copyright (c) 2022 Vac Research
+
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+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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LICENSE-MIT

@@ -0,0 +1,25 @@
+Copyright (c) 2022 Vac Research
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
+limitation the rights to use, copy, modify, merge,
+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE O THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.

Makefile

@@ -0,0 +1,38 @@
+.PHONY: all installdeps build test bench clean
+
+all: installdeps build
+
+.fetch-submodules:
+	@git submodule update --init --recursive
+
+.pre-build: .fetch-submodules
+	@cargo install cargo-make
+ifdef CI
+	@cargo install cross --git https://github.com/cross-rs/cross.git --rev 1511a28
+endif
+
+installdeps: .pre-build
+ifeq ($(shell uname),Darwin)
+	@brew install ninja binaryen
+else ifeq ($(shell uname),Linux)
+	@if [ -f /etc/os-release ] && grep -q "ID=nixos" /etc/os-release; then \
+		echo "Detected NixOS, skipping apt-get installation."; \
+	else \
+		sudo apt-get install -y cmake ninja-build binaryen; \
+	fi
+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: installdeps
+	@cargo make build
+
+test: build
+	@cargo make test
+
+bench: build
+	@cargo make bench
+
+clean:
+	@cargo clean

Makefile.toml

@@ -0,0 +1,2 @@
+[env]
+CARGO_MAKE_EXTEND_WORKSPACE_MAKEFILE = true

README.md

@@ -1,19 +1,86 @@
 # Zerokit
 
-A set of Zero Knowledge modules, written in Rust and designed to be used in other system programming environments.
+[![Crates.io](https://img.shields.io/crates/v/rln.svg)](https://crates.io/crates/rln)
+[![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/vacp2p/zerokit/ci.yml?branch=master&label=CI)](https://github.com/vacp2p/zerokit/actions)
+[![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)
 
-## Initial scope
+A collection of Zero Knowledge modules written in Rust and designed to be used in other system programming environments.
 
-Focus on RLN and being able to use [Circom](https://iden3.io/circom) based
-version through ark-circom, as opposed to the native one that currently exists
-in Rust.
+## Overview
+
+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)
+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
+- **Circom Compatibility**: Uses Circom-based circuits for RLN
+- **Cross-Platform**: Support for multiple architectures (see compatibility note below)
+- **FFI-Friendly**: Easy to integrate with other languages
+
+## 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.
+
+## Build and Test
+
+### Install Dependencies
+
+```bash
+make installdeps
+```
+
+#### Use Nix to install dependencies
+
+```bash
+nix develop
+```
+
+### Build and Test All Crates
+
+```bash
+make build
+make test
+```
+
+## Release Assets
+
+We use [`cross-rs`](https://github.com/cross-rs/cross) to cross-compile and generate release assets:
+
+```bash
+# Example: Build for specific target
+cross build --target x86_64-unknown-linux-gnu --release -p rln
+```
+
+## Used By
+
+Zerokit powers zero-knowledge functionality in:
+
+- [**nwaku**](https://github.com/waku-org/nwaku) - Nim implementation of the Waku v2 protocol
+- [**js-rln**](https://github.com/waku-org/js-rln) - JavaScript bindings for RLN
 
 ## Acknowledgements
 
-- Uses [ark-circom](https://github.com/gakonst/ark-circom), Rust wrapper around Circom.
+- Inspired by [Applied ZKP](https://zkp.science/) group work, including [zk-kit](https://github.com/appliedzkp/zk-kit)
+- Uses [ark-circom](https://github.com/gakonst/ark-circom) for zkey and Groth16 proof generation
+- Witness calculation based on [circom-witnesscalc](https://github.com/iden3/circom-witnesscalc) by iden3.
+The execution graph file used by this code has been generated by means of the same iden3 software.
 
-- Inspired by Applied ZKP group work, e.g. [zk-kit](https://github.com/appliedzkp/zk-kit).
+> [!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.
 
-- [RLN library](https://github.com/kilic/rln) written in Rust based on Bellman.
+## Documentation
 
-- [semaphore-rs](https://github.com/worldcoin/semaphore-rs) written in Rust based on ark-circom.
+For detailed documentation on each module:
+
+```bash
+cargo doc --open
+```

flake.lock

@@ -0,0 +1,48 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1740603184,
+        "narHash": "sha256-t+VaahjQAWyA+Ctn2idyo1yxRIYpaDxMgHkgCNiMJa4=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f44bd8ca21e026135061a0a57dcf3d0775b67a49",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f44bd8ca21e026135061a0a57dcf3d0775b67a49",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "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"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,69 @@
+{
+  description = "A flake for building zerokit";
+
+  inputs = {
+    # Version 24.11
+    nixpkgs.url = "github:NixOS/nixpkgs?rev=f44bd8ca21e026135061a0a57dcf3d0775b67a49";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, rust-overlay }:
+    let
+      stableSystems = [
+        "x86_64-linux" "aarch64-linux"
+        "x86_64-darwin" "aarch64-darwin"
+        "x86_64-windows" "i686-linux"
+        "i686-windows"
+      ];
+      forAllSystems = nixpkgs.lib.genAttrs stableSystems;
+      overlays = [
+        (import rust-overlay)
+        (f: p: { inherit rust-overlay; })
+      ];
+      pkgsFor = forAllSystems (system: import nixpkgs { inherit system overlays; });
+    in rec
+    {
+      packages = forAllSystems (system: let
+        pkgs = pkgsFor.${system};
+        buildPackage = pkgs.callPackage ./nix/default.nix;
+        buildRln = (buildPackage { src = self; project = "rln"; }).override;
+      in rec {
+        rln = buildRln { };
+
+        rln-linux-arm64 = buildRln {
+          target-platform = "aarch64-multiplatform";
+          rust-target = "aarch64-unknown-linux-gnu";
+        };
+
+        rln-android-arm64 = buildRln {
+          target-platform = "aarch64-android-prebuilt";
+          rust-target = "aarch64-linux-android";
+        };
+
+        rln-ios-arm64 = buildRln {
+          target-platform = "aarch64-darwin";
+          rust-target = "aarch64-apple-ios";
+        };
+
+        # TODO: Remove legacy name for RLN android library
+        zerokit-android-arm64 = rln-android-arm64;
+
+        default = rln;
+      });
+
+      devShells = forAllSystems (system: let
+        pkgs = pkgsFor.${system};
+      in {
+        default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            git cmake cargo-make rustup
+            binaryen ninja gnuplot
+            rust-bin.stable.latest.default
+          ];
+        };
+      });
+    };
+}

multiplier/Cargo.toml

@@ -1,35 +0,0 @@
-[package]
-name = "multiplier"
-version = "0.1.0"
-edition = "2018"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-
-# WASM operations
-# wasmer = { version = "2.0" }
-# fnv = { version = "1.0.3", default-features = false }
-# num = { version = "0.4.0" }
-# num-traits = { version = "0.2.0", default-features = false }
-num-bigint = { version = "0.4", default-features = false, features = ["rand"] }
-
-# ZKP Generation
-ark-ec = { version = "0.3.0", default-features = false, features = ["parallel"] }
-# ark-ff = { version = "0.3.0", default-features = false, features = ["parallel", "asm"] }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-bn254 = { version = "0.3.0" }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-# ark-poly = { version = "^0.3.0", default-features = false, features = ["parallel"] }
-ark-relations = { version = "0.3.0", default-features = false }
-ark-serialize = { version = "0.3.0", default-features = false }
-
-ark-circom = { git = "https://github.com/gakonst/ark-circom", features = ["circom-2"] }
-
-# error handling
-# thiserror = "1.0.26"
-color-eyre = "0.5"
-
-# decoding of data
-# hex = "0.4.3"
-# byteorder = "1.4.3"

multiplier/README.md

@@ -1,13 +0,0 @@
-# Multiplier example
-
-Example wrapper around a basic Circom circuit to test Circom 2 integration
-through ark-circom and FFI.
-
-# FFI
-
-To generate C or Nim bindings from Rust FFI, use `cbindgen` or `nbindgen`:
-
-```
-cbindgen . -o target/multiplier.h
-nbindgen . -o target/multiplier.nim
-```

multiplier/src/ffi.rs

@@ -1,77 +0,0 @@
-use crate::public::Multiplier;
-use std::slice;
-
-/// 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[0] as *const u8,
-            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) }
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn new_circuit(ctx: *mut *mut Multiplier) -> bool {
-    println!("multiplier ffi: new");
-    let mul = Multiplier::new();
-
-    unsafe { *ctx = Box::into_raw(Box::new(mul)) };
-
-    true
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn prove(ctx: *const Multiplier, output_buffer: *mut Buffer) -> bool {
-    println!("multiplier ffi: prove");
-    let mul = unsafe { &*ctx };
-    let mut output_data: Vec<u8> = Vec::new();
-
-    match mul.prove(&mut output_data) {
-        Ok(proof_data) => proof_data,
-        Err(_) => return false,
-    };
-    unsafe { *output_buffer = Buffer::from(&output_data[..]) };
-    std::mem::forget(output_data);
-    true
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn verify(
-    ctx: *const Multiplier,
-    proof_buffer: *const Buffer,
-    result_ptr: *mut u32,
-) -> bool {
-    println!("multiplier ffi: verify");
-    let mul = unsafe { &*ctx };
-    let proof_data = <&[u8]>::from(unsafe { &*proof_buffer });
-    if match mul.verify(proof_data) {
-        Ok(verified) => verified,
-        Err(_) => return false,
-    } {
-        unsafe { *result_ptr = 0 };
-    } else {
-        unsafe { *result_ptr = 1 };
-    };
-    true
-}

multiplier/src/lib.rs

@@ -1,2 +0,0 @@
-pub mod ffi;
-pub mod public;

multiplier/src/main.rs

@@ -1,48 +0,0 @@
-use ark_circom::{CircomBuilder, CircomConfig};
-use ark_std::rand::thread_rng;
-use color_eyre::Result;
-
-use ark_bn254::Bn254;
-use ark_groth16::{
-    create_random_proof as prove, generate_random_parameters, prepare_verifying_key, verify_proof,
-};
-
-fn groth16_proof_example() -> Result<()> {
-    let cfg = CircomConfig::<Bn254>::new(
-        "./resources/circom2_multiplier2.wasm",
-        "./resources/circom2_multiplier2.r1cs",
-    )?;
-
-    let mut builder = CircomBuilder::new(cfg);
-    builder.push_input("a", 3);
-    builder.push_input("b", 11);
-
-    // create an empty instance for setting it up
-    let circom = builder.setup();
-
-    let mut rng = thread_rng();
-    let params = generate_random_parameters::<Bn254, _, _>(circom, &mut rng)?;
-
-    let circom = builder.build()?;
-
-    let inputs = circom.get_public_inputs().unwrap();
-
-    let proof = prove(circom, &params, &mut rng)?;
-
-    let pvk = prepare_verifying_key(&params.vk);
-
-    let verified = verify_proof(&pvk, &proof, &inputs)?;
-
-    assert!(verified);
-
-    Ok(())
-}
-
-fn main() {
-    println!("Hello, world!");
-
-    match groth16_proof_example() {
-        Ok(_) => println!("Success"),
-        Err(_) => println!("Error"),
-    }
-}

multiplier/src/public.rs

@@ -1,98 +0,0 @@
-use ark_circom::{CircomBuilder, CircomCircuit, CircomConfig};
-use ark_std::rand::thread_rng;
-
-use ark_bn254::Bn254;
-use ark_groth16::{
-    create_random_proof as prove, generate_random_parameters, prepare_verifying_key, verify_proof,
-    Proof, ProvingKey,
-};
-use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
-// , SerializationError};
-
-use std::io::{self, Read, Write};
-
-pub struct Multiplier {
-    circom: CircomCircuit<Bn254>,
-    params: ProvingKey<Bn254>,
-}
-
-impl Multiplier {
-    // TODO Break this apart here
-    pub fn new() -> Multiplier {
-        let cfg = CircomConfig::<Bn254>::new(
-            "./resources/circom2_multiplier2.wasm",
-            "./resources/circom2_multiplier2.r1cs",
-        )
-        .unwrap();
-
-        let mut builder = CircomBuilder::new(cfg);
-        builder.push_input("a", 3);
-        builder.push_input("b", 11);
-
-        // create an empty instance for setting it up
-        let circom = builder.setup();
-
-        let mut rng = thread_rng();
-
-        let params = generate_random_parameters::<Bn254, _, _>(circom, &mut rng).unwrap();
-
-        let circom = builder.build().unwrap();
-
-        //let inputs = circom.get_public_inputs().unwrap();
-
-        Multiplier { circom, params }
-    }
-
-    // TODO Input Read
-    pub fn prove<W: Write>(&self, result_data: W) -> io::Result<()> {
-        let mut rng = thread_rng();
-
-        // XXX: There's probably a better way to do this
-        let circom = self.circom.clone();
-        let params = self.params.clone();
-
-        let proof = prove(circom, &params, &mut rng).unwrap();
-
-        // XXX: Unclear if this is different from other serialization(s)
-        let _ = proof.serialize(result_data).unwrap();
-
-        Ok(())
-    }
-
-    pub fn verify<R: Read>(&self, input_data: R) -> io::Result<bool> {
-        let proof = Proof::deserialize(input_data).unwrap();
-
-        let pvk = prepare_verifying_key(&self.params.vk);
-
-        // XXX Part of input data?
-        let inputs = self.circom.get_public_inputs().unwrap();
-
-        let verified = verify_proof(&pvk, &proof, &inputs).unwrap();
-
-        Ok(verified)
-    }
-}
-
-impl Default for Multiplier {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-#[test]
-fn multiplier_proof() {
-    let mul = Multiplier::new();
-    //let inputs = mul.circom.get_public_inputs().unwrap();
-
-    let mut output_data: Vec<u8> = Vec::new();
-    let _ = mul.prove(&mut output_data);
-
-    let proof_data = &output_data[..];
-
-    // XXX Pass as arg?
-    //let pvk = prepare_verifying_key(&mul.params.vk);
-
-    let verified = mul.verify(proof_data).unwrap();
-
-    assert!(verified);
-}

nix/default.nix

@@ -0,0 +1,64 @@
+{
+  pkgs,
+  rust-overlay,
+  project,
+  src ? ../.,
+  release ? true,
+  target-platform ? null,
+  rust-target ? null,
+  features ? null,
+}:
+
+let
+  # Use cross-compilation if target-platform is specified.
+  targetPlatformPkgs = if target-platform != null
+    then pkgs.pkgsCross.${target-platform}
+    else pkgs;
+
+  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 = src + "/Cargo.lock";
+    allowBuiltinFetchGit = true;
+  };
+
+  nativeBuildInputs = [ pkgs.rust-cbindgen ];
+
+  doCheck = false;
+
+  CARGO_HOME = "/tmp";
+
+  buildPhase = ''
+    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 = ''
+    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/Cargo.toml

@@ -0,0 +1,25 @@
+[package]
+name = "rln-cli"
+version = "0.4.0"
+edition = "2021"
+
+[[example]]
+name = "relay"
+path = "src/examples/relay.rs"
+
+[[example]]
+name = "stateless"
+path = "src/examples/stateless.rs"
+required-features = ["stateless"]
+
+[dependencies]
+rln = { path = "../rln", version = "0.8.0", default-features = false }
+zerokit_utils = { path = "../utils", version = "0.6.0", default-features = false }
+clap = { version = "4.5.41", features = ["cargo", "derive", "env"] }
+color-eyre = "0.6.5"
+serde_json = "1.0.141"
+serde = { version = "1.0", features = ["derive"] }
+
+[features]
+default = ["rln/pmtree-ft", "rln/parallel"]
+stateless = ["rln/stateless", "rln/parallel"]

rln-cli/Makefile.toml

@@ -0,0 +1,9 @@
+[tasks.build]
+command = "cargo"
+args = ["build"]
+
+[tasks.test]
+disabled = true
+
+[tasks.bench]
+disabled = true

rln-cli/README.md

@@ -0,0 +1,148 @@
+# 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.
+
+## Relay Example
+
+The following [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:
+
+```bash
+cargo run --example relay
+```
+
+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.
+
+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.
+
+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 --no-default-features --features stateless
+```
+
+## CLI Commands
+
+### Instance Management
+
+To initialize a new RLN instance:
+
+```bash
+cargo run new --tree-depth <DEPTH>
+```
+
+To initialize an RLN instance with custom parameters:
+
+```bash
+cargo run new-with-params --resources-path <PATH> --tree-depth <DEPTH>
+```
+
+To update the Merkle tree depth:
+
+```bash
+cargo run set-tree --tree-depth <DEPTH>
+```
+
+### 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>
+```

rln-cli/example.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-cli/src/commands.rs

@@ -0,0 +1,69 @@
+use std::path::PathBuf;
+
+use clap::Subcommand;
+use rln::circuit::TEST_TREE_DEPTH;
+
+#[derive(Subcommand)]
+pub(crate) enum Commands {
+    New {
+        #[arg(short, long, default_value_t = TEST_TREE_DEPTH)]
+        tree_depth: usize,
+    },
+    NewWithParams {
+        #[arg(short, long, default_value_t = TEST_TREE_DEPTH)]
+        tree_depth: usize,
+        #[arg(short, long, default_value = "../rln/resources/tree_depth_30")]
+        resources_path: PathBuf,
+    },
+    SetTree {
+        #[arg(short, long, default_value_t = TEST_TREE_DEPTH)]
+        tree_depth: 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

@@ -0,0 +1,31 @@
+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(Serialize, Deserialize)]
+pub(crate) struct Config {
+    pub tree_config: Option<String>,
+}
+
+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 tree_config: Value = serde_json::from_str(&contents)?;
+                println!("Initializing RLN with custom config");
+                Ok(Config {
+                    tree_config: Some(tree_config.to_string()),
+                })
+            }
+            Err(_) => Ok(Config { tree_config: None }),
+        }
+    }
+}

rln-cli/src/examples/relay.rs

@@ -0,0 +1,315 @@
+use std::{
+    collections::HashMap,
+    fs::File,
+    io::{stdin, stdout, Cursor, Read, Write},
+    path::{Path, PathBuf},
+};
+
+use clap::{Parser, Subcommand};
+use color_eyre::{eyre::eyre, Report, Result};
+use rln::{
+    circuit::Fr,
+    hashers::{hash_to_field_le, poseidon_hash},
+    protocol::{keygen, prepare_prove_input, prepare_verify_input},
+    public::RLN,
+    utils::{fr_to_bytes_le, generate_input_buffer, IdSecret},
+};
+
+const MESSAGE_LIMIT: u32 = 1;
+
+const TREE_DEPTH: usize = 30;
+
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    #[command(subcommand)]
+    command: Commands,
+}
+
+#[derive(Subcommand)]
+enum Commands {
+    List,
+    Register,
+    Send {
+        #[arg(short, long)]
+        user_index: usize,
+        #[arg(short, long)]
+        message_id: u32,
+        #[arg(short, long)]
+        signal: String,
+    },
+    Clear,
+    Exit,
+}
+
+#[derive(Debug, Clone)]
+struct Identity {
+    identity_secret_hash: IdSecret,
+    id_commitment: Fr,
+}
+
+impl Identity {
+    fn new() -> Self {
+        let (identity_secret_hash, id_commitment) = keygen();
+        Identity {
+            identity_secret_hash,
+            id_commitment,
+        }
+    }
+}
+
+struct RLNSystem {
+    rln: RLN,
+    used_nullifiers: HashMap<[u8; 32], Vec<u8>>,
+    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_depth_{TREE_DEPTH}").into();
+        let filenames = ["rln_final.arkzkey", "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 rln = RLN::new_with_params(
+            TREE_DEPTH,
+            resources[0].clone(),
+            resources[1].clone(),
+            generate_input_buffer(),
+        )?;
+        println!("RLN instance initialized successfully");
+        Ok(RLNSystem {
+            rln,
+            used_nullifiers: HashMap::new(),
+            local_identities: HashMap::new(),
+        })
+    }
+
+    fn list_users(&self) {
+        if self.local_identities.is_empty() {
+            println!("No users registered yet.");
+            return;
+        }
+
+        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!();
+        }
+    }
+
+    fn register_user(&mut self) -> Result<usize> {
+        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) {
+            Ok(_) => {
+                println!("Registered User Index: {index}");
+                println!("+ Identity secret hash: {}", *identity.identity_secret_hash);
+                println!("+ Identity commitment: {},", identity.id_commitment);
+                self.local_identities.insert(index, identity);
+            }
+            Err(_) => {
+                println!("Maximum user limit reached: 2^{TREE_DEPTH}");
+            }
+        };
+
+        Ok(index)
+    }
+
+    fn generate_proof(
+        &mut self,
+        user_index: usize,
+        message_id: u32,
+        signal: &str,
+        external_nullifier: Fr,
+    ) -> Result<Vec<u8>> {
+        let identity = match self.local_identities.get(&user_index) {
+            Some(identity) => identity,
+            None => return Err(eyre!("user index {user_index} not found")),
+        };
+
+        let serialized = prepare_prove_input(
+            identity.identity_secret_hash.clone(),
+            user_index,
+            Fr::from(MESSAGE_LIMIT),
+            Fr::from(message_id),
+            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)?;
+
+        println!("Proof generated successfully:");
+        println!("+ User Index: {user_index}");
+        println!("+ Message ID: {message_id}");
+        println!("+ Signal: {signal}");
+
+        Ok(output_buffer.into_inner())
+    }
+
+    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);
+
+        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)?;
+                    return Ok(());
+                }
+                self.used_nullifiers.insert(nullifier_key, proof_data);
+                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(Report::new(err)),
+        }
+        Ok(())
+    }
+
+    fn handle_duplicate_message_id(
+        &mut self,
+        previous_proof: Vec<u8>,
+        current_proof: Vec<u8>,
+    ) -> 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"));
+        }
+
+        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, _) = IdSecret::from_bytes_le(&output_data);
+
+                if let Some((user_index, identity)) = self
+                    .local_identities
+                    .iter()
+                    .find(|(_, identity)| {
+                        identity.identity_secret_hash == leaked_identity_secret_hash
+                    })
+                    .map(|(index, identity)| (*index, identity))
+                {
+                    let real_identity_secret_hash = identity.identity_secret_hash.clone();
+                    if leaked_identity_secret_hash != real_identity_secret_hash {
+                        Err(eyre!("identity secret hash mismatch: leaked_identity_secret_hash != real_identity_secret_hash"))
+                    } else {
+                        println!(
+                            "DUPLICATE message ID detected! Reveal identity secret hash: {}",
+                            *leaked_identity_secret_hash
+                        );
+                        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 ******** not found"))
+                }
+            }
+            Err(err) => Err(eyre!("Failed to recover identity secret: {err}")),
+        }
+    }
+}
+
+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_le(b"epoch");
+    let rln_identifier = hash_to_field_le(b"rln-identifier");
+    let external_nullifier = poseidon_hash(&[rln_epoch, rln_identifier]);
+    println!("RLN Relay Example:");
+    println!("Message Limit: {MESSAGE_LIMIT}");
+    println!("----------------------------------");
+    println!();
+    show_commands();
+    loop {
+        print!("\n> ");
+        stdout().flush()?;
+        let mut input = String::new();
+        stdin().read_line(&mut input)?;
+        let trimmed = input.trim();
+        let args = std::iter::once("").chain(trimmed.split_whitespace());
+
+        match Cli::try_parse_from(args) {
+            Ok(cli) => match cli.command {
+                Commands::List => {
+                    rln_system.list_users();
+                }
+                Commands::Register => {
+                    rln_system.register_user()?;
+                }
+                Commands::Send {
+                    user_index,
+                    message_id,
+                    signal,
+                } => {
+                    match rln_system.generate_proof(
+                        user_index,
+                        message_id,
+                        &signal,
+                        external_nullifier,
+                    ) {
+                        Ok(proof) => {
+                            if let Err(err) = rln_system.verify_proof(proof, &signal) {
+                                println!("Verification error: {err}");
+                            };
+                        }
+                        Err(err) => {
+                            println!("Proof generation error: {err}");
+                        }
+                    }
+                }
+                Commands::Clear => {
+                    print!("\x1B[2J\x1B[1;1H");
+                    show_commands();
+                }
+                Commands::Exit => {
+                    break;
+                }
+            },
+            Err(err) => {
+                eprintln!("Command error: {err}");
+            }
+        }
+    }
+    Ok(())
+}
+
+fn show_commands() {
+    println!("Available commands:");
+    println!("  list                                        - List registered users");
+    println!("  register                                    - Register a new user index");
+    println!("  send -u <index> -m <message_id> -s <signal> - Send a message with proof");
+    println!("  clear                                       - Clear the screen");
+    println!("  exit                                        - Exit the program");
+}

rln-cli/src/examples/stateless.rs

@@ -0,0 +1,316 @@
+#![cfg(feature = "stateless")]
+
+use std::{
+    collections::HashMap,
+    io::{stdin, stdout, Cursor, Write},
+};
+
+use clap::{Parser, Subcommand};
+use color_eyre::{eyre::eyre, Result};
+use rln::{
+    circuit::{Fr, TEST_TREE_DEPTH},
+    hashers::{hash_to_field_le, poseidon_hash, PoseidonHash},
+    protocol::{keygen, prepare_verify_input, rln_witness_from_values, serialize_witness},
+    public::RLN,
+    utils::{fr_to_bytes_le, IdSecret},
+};
+use zerokit_utils::{OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree};
+
+const MESSAGE_LIMIT: u32 = 1;
+
+type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
+
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    #[command(subcommand)]
+    command: Commands,
+}
+
+#[derive(Subcommand)]
+enum Commands {
+    List,
+    Register,
+    Send {
+        #[arg(short, long)]
+        user_index: usize,
+        #[arg(short, long)]
+        message_id: u32,
+        #[arg(short, long)]
+        signal: String,
+    },
+    Clear,
+    Exit,
+}
+
+#[derive(Debug, Clone)]
+struct Identity {
+    identity_secret_hash: IdSecret,
+    id_commitment: Fr,
+}
+
+impl Identity {
+    fn new() -> Self {
+        let (identity_secret_hash, id_commitment) = keygen();
+        Identity {
+            identity_secret_hash,
+            id_commitment,
+        }
+    }
+}
+
+struct RLNSystem {
+    rln: RLN,
+    tree: OptimalMerkleTree<PoseidonHash>,
+    used_nullifiers: HashMap<[u8; 32], Vec<u8>>,
+    local_identities: HashMap<usize, Identity>,
+}
+
+impl RLNSystem {
+    fn new() -> Result<Self> {
+        let rln = RLN::new()?;
+        let default_leaf = Fr::from(0);
+        let tree: OptimalMerkleTree<PoseidonHash> = OptimalMerkleTree::new(
+            TEST_TREE_DEPTH,
+            default_leaf,
+            ConfigOf::<OptimalMerkleTree<PoseidonHash>>::default(),
+        )
+        .unwrap();
+
+        Ok(RLNSystem {
+            rln,
+            tree,
+            used_nullifiers: HashMap::new(),
+            local_identities: HashMap::new(),
+        })
+    }
+
+    fn list_users(&self) {
+        if self.local_identities.is_empty() {
+            println!("No users registered yet.");
+            return;
+        }
+
+        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!();
+        }
+    }
+
+    fn register_user(&mut self) -> Result<usize> {
+        let index = self.tree.leaves_set();
+        let identity = Identity::new();
+
+        let rate_commitment = poseidon_hash(&[identity.id_commitment, Fr::from(MESSAGE_LIMIT)]);
+        self.tree.update_next(rate_commitment)?;
+
+        println!("Registered User Index: {index}");
+        println!("+ Identity secret hash: {}", *identity.identity_secret_hash);
+        println!("+ Identity commitment: {}", identity.id_commitment);
+
+        self.local_identities.insert(index, identity);
+        Ok(index)
+    }
+
+    fn generate_proof(
+        &mut self,
+        user_index: usize,
+        message_id: u32,
+        signal: &str,
+        external_nullifier: Fr,
+    ) -> Result<Vec<u8>> {
+        let identity = match self.local_identities.get(&user_index) {
+            Some(identity) => identity,
+            None => return Err(eyre!("user index {user_index} not found")),
+        };
+
+        let merkle_proof = self.tree.proof(user_index)?;
+        let x = hash_to_field_le(signal.as_bytes());
+
+        let rln_witness = rln_witness_from_values(
+            identity.identity_secret_hash.clone(),
+            merkle_proof.get_path_elements(),
+            merkle_proof.get_path_index(),
+            x,
+            external_nullifier,
+            Fr::from(MESSAGE_LIMIT),
+            Fr::from(message_id),
+        )?;
+
+        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)?;
+
+        println!("Proof generated successfully:");
+        println!("+ User Index: {user_index}");
+        println!("+ Message ID: {message_id}");
+        println!("+ Signal: {signal}");
+
+        Ok(output_buffer.into_inner())
+    }
+
+    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);
+
+        let root = self.tree.root();
+        let roots_serialized = fr_to_bytes_le(&root);
+        let mut roots_buffer = Cursor::new(roots_serialized);
+
+        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)?;
+                    return Ok(());
+                }
+                self.used_nullifiers.insert(nullifier_key, proof_data);
+                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>,
+    ) -> 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"));
+        }
+
+        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, _) = IdSecret::from_bytes_le(&output_data);
+
+                if let Some((user_index, identity)) = self
+                    .local_identities
+                    .iter()
+                    .find(|(_, identity)| {
+                        identity.identity_secret_hash == leaked_identity_secret_hash
+                    })
+                    .map(|(index, identity)| (*index, identity))
+                {
+                    let real_identity_secret_hash = identity.identity_secret_hash.clone();
+                    if leaked_identity_secret_hash != real_identity_secret_hash {
+                        Err(eyre!("identity secret hash mismatch: leaked_identity_secret_hash != real_identity_secret_hash"))
+                    } else {
+                        println!(
+                            "DUPLICATE message ID detected! Reveal identity secret hash: ********"
+                        );
+                        self.local_identities.remove(&user_index);
+                        println!("User index {user_index} has been SLASHED");
+                        Ok(())
+                    }
+                } else {
+                    Err(eyre!("user identity secret hash ******** not found"))
+                }
+            }
+            Err(err) => Err(eyre!("Failed to recover identity secret: {err}")),
+        }
+    }
+}
+
+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_le(b"epoch");
+    let rln_identifier = hash_to_field_le(b"rln-identifier");
+    let external_nullifier = poseidon_hash(&[rln_epoch, rln_identifier]);
+    println!("RLN Stateless Relay Example:");
+    println!("Message Limit: {MESSAGE_LIMIT}");
+    println!("----------------------------------");
+    println!();
+    show_commands();
+
+    loop {
+        print!("\n> ");
+        stdout().flush()?;
+        let mut input = String::new();
+        stdin().read_line(&mut input)?;
+        let trimmed = input.trim();
+        let args = std::iter::once("").chain(trimmed.split_whitespace());
+
+        match Cli::try_parse_from(args) {
+            Ok(cli) => match cli.command {
+                Commands::List => {
+                    rln_system.list_users();
+                }
+                Commands::Register => {
+                    rln_system.register_user()?;
+                }
+                Commands::Send {
+                    user_index,
+                    message_id,
+                    signal,
+                } => {
+                    match rln_system.generate_proof(
+                        user_index,
+                        message_id,
+                        &signal,
+                        external_nullifier,
+                    ) {
+                        Ok(proof) => {
+                            if let Err(err) = rln_system.verify_proof(proof, &signal) {
+                                println!("Verification error: {err}");
+                            };
+                        }
+                        Err(err) => {
+                            println!("Proof generation error: {err}");
+                        }
+                    }
+                }
+                Commands::Clear => {
+                    print!("\x1B[2J\x1B[1;1H");
+                    show_commands();
+                }
+                Commands::Exit => {
+                    break;
+                }
+            },
+            Err(err) => {
+                eprintln!("Command error: {err}");
+            }
+        }
+    }
+    Ok(())
+}
+
+fn show_commands() {
+    println!("Available commands:");
+    println!("  list                                        - List registered users");
+    println!("  register                                    - Register a new user index");
+    println!("  send -u <index> -m <message_id> -s <signal> - Send a message with proof");
+    println!("  clear                                       - Clear the screen");
+    println!("  exit                                        - Exit the program");
+}

rln-cli/src/main.rs

@@ -0,0 +1,195 @@
+use std::{
+    fs::File,
+    io::{Cursor, Read},
+    path::Path,
+};
+
+use clap::Parser;
+use color_eyre::{eyre::Report, Result};
+use commands::Commands;
+use config::Config;
+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_depth }) => {
+            let config = Config::load_config()?;
+            state.rln = if let Some(tree_config) = config.tree_config {
+                println!("Initializing RLN with custom config");
+                Some(RLN::new(tree_depth, Cursor::new(tree_config.as_bytes()))?)
+            } else {
+                println!("Initializing RLN with default config");
+                Some(RLN::new(tree_depth, Cursor::new(json!({}).to_string()))?)
+            };
+            Ok(())
+        }
+        Some(Commands::NewWithParams {
+            tree_depth,
+            resources_path,
+        }) => {
+            let mut resources: Vec<Vec<u8>> = Vec::new();
+            let filenames = ["rln_final.arkzkey", "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 buffer = vec![0; metadata.len() as usize];
+                file.read_exact(&mut buffer)?;
+                resources.push(buffer);
+            }
+            let config = Config::load_config()?;
+            if let Some(tree_config) = config.tree_config {
+                println!("Initializing RLN with custom config");
+                state.rln = Some(RLN::new_with_params(
+                    tree_depth,
+                    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_depth,
+                    resources[0].clone(),
+                    resources[1].clone(),
+                    Cursor::new(json!({}).to_string()),
+                )?)
+            };
+            Ok(())
+        }
+        Some(Commands::SetTree { tree_depth }) => {
+            state
+                .rln
+                .ok_or(Report::msg("no RLN instance initialized"))?
+                .set_tree(tree_depth)?;
+            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

@@ -0,0 +1,31 @@
+use std::io::Cursor;
+
+use color_eyre::Result;
+use rln::{circuit::TEST_TREE_DEPTH, public::RLN};
+use serde_json::Value;
+
+use crate::config::Config;
+
+#[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(tree_config) = config.tree_config {
+            let config_json: Value = serde_json::from_str(&tree_config)?;
+            let tree_depth = config_json["tree_depth"]
+                .as_u64()
+                .unwrap_or(TEST_TREE_DEPTH as u64);
+            Some(RLN::new(
+                tree_depth as usize,
+                Cursor::new(tree_config.as_bytes()),
+            )?)
+        } else {
+            None
+        };
+        Ok(State { rln })
+    }
+}

rln-wasm-utils/.gitignore

@@ -0,0 +1,21 @@
+# Common files to ignore in Rust projects
+.DS_Store
+.idea
+*.log
+tmp/
+
+# Generated by Cargo will have compiled files and executables
+/target
+Cargo.lock
+
+# Generated by rln-wasm
+pkg/
+
+# 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-wasm-utils/Cargo.toml

@@ -0,0 +1,35 @@
+[package]
+name = "rln-wasm-utils"
+version = "0.1.0"
+edition = "2024"
+
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+# TODO: remove this once we have a proper release
+rln = { path = "../rln", default-features = false, features = ["stateless"] }
+js-sys = "0.3.77"
+wasm-bindgen = "0.2.100"
+rand = "0.8.5"
+
+# The `console_error_panic_xhook` 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 }
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+getrandom = { version = "0.2.16", features = ["js"] }
+
+[dev-dependencies]
+wasm-bindgen-test = "0.3.50"
+web-sys = { version = "0.3.77", features = ["console"] }
+ark-std = { version = "0.5.0", default-features = false }
+
+[features]
+default = ["console_error_panic_hook"]
+
+[package.metadata.docs.rs]
+all-features = true

rln-wasm-utils/Makefile.toml

@@ -0,0 +1,36 @@
+[tasks.build]
+clear = true
+dependencies = ["pack_build", "pack_rename", "pack_resize"]
+
+[tasks.pack_build]
+command = "wasm-pack"
+args = ["build", "--release", "--target", "web", "--scope", "waku"]
+
+[tasks.pack_rename]
+script = "sed -i.bak 's/rln-wasm-utils/zerokit-rln-wasm-utils/g' pkg/package.json && rm pkg/package.json.bak"
+
+[tasks.pack_resize]
+command = "wasm-opt"
+args = [
+    "pkg/rln_wasm_utils_bg.wasm",
+    "-Oz",
+    "--strip-debug",
+    "--strip-dwarf",
+    "--remove-unused-module-elements",
+    "--vacuum",
+    "-o",
+    "pkg/rln_wasm_utils_bg.wasm",
+]
+
+[tasks.test]
+command = "wasm-pack"
+args = [
+    "test",
+    "--release",
+    "--node",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build"]

rln-wasm-utils/README.md

@@ -0,0 +1,206 @@
+# RLN WASM Utils
+
+[![npm version](https://badge.fury.io/js/@waku%2Fzerokit-rln-wasm.svg)](https://badge.fury.io/js/@waku%2Fzerokit-rln-wasm-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)
+
+The Zerokit RLN WASM Utils Module provides WebAssembly bindings for Rate-Limiting Nullifier [RLN](https://rfc.vac.dev/spec/32/) cryptographic primitives.
+This module offers comprehensive functionality for identity generation and hashing needed for RLN applications.
+
+## Features
+
+### Identity Generation
+
+- **Random Identity Generation**: Generate cryptographically secure random identities
+- **Seeded Identity Generation**: Generate deterministic identities from seeds
+- **Extended Identity Generation**: Generate extended identities with additional parameters
+- **Seeded Extended Identity Generation**: Generate deterministic extended identities from seeds
+- **Endianness Support**: Both little-endian and big-endian serialization support
+
+### Hashing
+
+- **Standard Hashing**: Hash arbitrary data to field elements
+- **Poseidon Hashing**: Advanced cryptographic hashing using Poseidon hash function
+- **Endianness Support**: Both little-endian and big-endian serialization support
+
+## API Reference
+
+### Identity Generation Functions
+
+#### `generateMembershipKey(isLittleEndian: boolean): Uint8Array`
+
+Generates a random membership key pair (identity secret and commitment).
+
+**Inputs:**
+
+- `isLittleEndian`: Boolean indicating endianness for serialization
+
+**Outputs:** Serialized identity pair as `Uint8Array` in corresponding endianness
+
+#### `generateExtendedMembershipKey(isLittleEndian: boolean): Uint8Array`
+
+Generates an extended membership key with additional parameters.
+
+**Inputs:**
+
+- `isLittleEndian`: Boolean indicating endianness for serialization
+
+**Outputs:** Serialized extended identity tuple as `Uint8Array` in corresponding endianness
+
+#### `generateSeededMembershipKey(seed: Uint8Array, isLittleEndian: boolean): Uint8Array`
+
+Generates a deterministic membership key from a seed.
+
+**Inputs:**
+
+- `seed`: Seed data as `Uint8Array`
+- `isLittleEndian`: Boolean indicating endianness for serialization
+
+**Outputs:** Serialized identity pair as `Uint8Array` in corresponding endianness
+
+#### `generateSeededExtendedMembershipKey(seed: Uint8Array, isLittleEndian: boolean): Uint8Array`
+
+Generates a deterministic extended membership key from a seed.
+
+**Inputs:**
+
+- `seed`: Seed data as `Uint8Array`
+- `isLittleEndian`: Boolean indicating endianness for serialization
+
+**Outputs:** Serialized extended identity tuple as `Uint8Array` in corresponding endianness
+
+### Hashing Functions
+
+#### `hash(input: Uint8Array, isLittleEndian: boolean): Uint8Array`
+
+Hashes input data to a field element.
+
+**Inputs:**
+
+- `input`: Input data as `Uint8Array`
+- `isLittleEndian`: Boolean indicating endianness for serialization
+
+**Outputs:** Serialized hash result as `Uint8Array` in corresponding endianness
+
+#### `poseidonHash(input: Uint8Array, isLittleEndian: boolean): Uint8Array`
+
+Computes Poseidon hash of input field elements.
+
+**Inputs:**
+
+- `input`: Serialized field elements as `Uint8Array` (format: length + field elements)
+- `isLittleEndian`: Boolean indicating endianness for serialization
+
+**Outputs:** Serialized hash result as `Uint8Array` in corresponding endianness
+
+## Usage Examples
+
+### JavaScript/TypeScript
+
+```javascript
+import init, { 
+  generateMembershipKey, 
+  generateSeededMembershipKey,
+  hash,
+  poseidonHash 
+} from '@waku/zerokit-rln-wasm-utils';
+
+// Initialize the WASM module
+await init();
+
+// Generate a random membership key
+const membershipKey = generateMembershipKey(true); // little-endian
+console.log('Membership key:', membershipKey);
+
+// Generate a deterministic membership key from seed
+const seed = new Uint8Array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+const seededKey = generateSeededMembershipKey(seed, true);
+console.log('Seeded key:', seededKey);
+
+// Hash some data
+const input = new Uint8Array([1, 2, 3, 4, 5, 6, 7, 8, 9, 10]);
+const hashResult = hash(input, true);
+console.log('Hash result:', hashResult);
+
+// Poseidon hash with field elements
+const fieldElements = new Uint8Array([
+  // Length (8 bytes) + field elements (32 bytes each)
+  1, 0, 0, 0, 0, 0, 0, 0, // length = 1
+  // field element data...
+]);
+const poseidonResult = poseidonHash(fieldElements, true);
+console.log('Poseidon hash:', poseidonResult);
+```
+
+## Install Dependencies
+
+> [!NOTE]
+> This project requires the following tools:
+>
+> - `wasm-pack` - for compiling Rust to WebAssembly
+> - `cargo-make` - for running build commands
+> - `nvm` - to install and manage Node.js
+>
+> Ensure all dependencies are installed before proceeding.
+
+### Manually
+
+#### Install `wasm-pack`
+
+```bash
+cargo install wasm-pack --version=0.13.1
+```
+
+#### Install `cargo-make`
+
+```bash
+cargo install cargo-make
+```
+
+#### Install `Node.js`
+
+If you don't have `nvm` (Node Version Manager), install it by following
+the [installation instructions](https://github.com/nvm-sh/nvm?tab=readme-ov-file#install--update-script).
+
+After installing `nvm`, install and use Node.js `v22.14.0`:
+
+```bash
+nvm install 22.14.0
+nvm use 22.14.0
+nvm alias default 22.14.0
+```
+
+If you already have Node.js installed,
+check your version with `node -v` command — the version must be strictly greater than 22.
+
+### Or install everything
+
+You can run the following command from the root of the repository to install all required dependencies for `zerokit`
+
+```bash
+make installdeps
+```
+
+## Building the library
+
+First, navigate to the rln-wasm-utils directory:
+
+```bash
+cd rln-wasm-utils
+```
+
+Compile rln-wasm-utils for `wasm32-unknown-unknown`:
+
+```bash
+cargo make build
+```
+
+## Running tests
+
+```bash
+cargo make test
+```
+
+## License
+
+This project is licensed under both MIT and Apache 2.0 licenses. See the LICENSE files for details.

rln-wasm-utils/src/lib.rs

@@ -0,0 +1,112 @@
+#![cfg(target_arch = "wasm32")]
+
+use js_sys::Uint8Array;
+use rln::public::{
+    extended_key_gen, hash, key_gen, poseidon_hash, seeded_extended_key_gen, seeded_key_gen,
+};
+use std::vec::Vec;
+use wasm_bindgen::prelude::*;
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[wasm_bindgen(js_name = generateMembershipKey)]
+pub fn wasm_key_gen(is_little_endian: bool) -> Result<Uint8Array, String> {
+    let mut output_data: Vec<u8> = Vec::new();
+    if let Err(err) = key_gen(&mut output_data, is_little_endian) {
+        std::mem::forget(output_data);
+        Err(format!(
+            "Msg: could not generate membership keys, Error: {:#?}",
+            err
+        ))
+    } else {
+        let result = Uint8Array::from(&output_data[..]);
+        std::mem::forget(output_data);
+        Ok(result)
+    }
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[wasm_bindgen(js_name = generateExtendedMembershipKey)]
+pub fn wasm_extended_key_gen(is_little_endian: bool) -> Result<Uint8Array, String> {
+    let mut output_data: Vec<u8> = Vec::new();
+    if let Err(err) = extended_key_gen(&mut output_data, is_little_endian) {
+        std::mem::forget(output_data);
+        Err(format!(
+            "Msg: could not generate membership keys, Error: {:#?}",
+            err
+        ))
+    } else {
+        let result = Uint8Array::from(&output_data[..]);
+        std::mem::forget(output_data);
+        Ok(result)
+    }
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[wasm_bindgen(js_name = generateSeededMembershipKey)]
+pub fn wasm_seeded_key_gen(seed: Uint8Array, is_little_endian: bool) -> Result<Uint8Array, String> {
+    let mut output_data: Vec<u8> = Vec::new();
+    let input_data = &seed.to_vec()[..];
+    if let Err(err) = seeded_key_gen(input_data, &mut output_data, is_little_endian) {
+        std::mem::forget(output_data);
+        Err(format!(
+            "Msg: could not generate membership key, Error: {:#?}",
+            err
+        ))
+    } else {
+        let result = Uint8Array::from(&output_data[..]);
+        std::mem::forget(output_data);
+        Ok(result)
+    }
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[wasm_bindgen(js_name = generateSeededExtendedMembershipKey)]
+pub fn wasm_seeded_extended_key_gen(
+    seed: Uint8Array,
+    is_little_endian: bool,
+) -> Result<Uint8Array, String> {
+    let mut output_data: Vec<u8> = Vec::new();
+    let input_data = &seed.to_vec()[..];
+    if let Err(err) = seeded_extended_key_gen(input_data, &mut output_data, is_little_endian) {
+        std::mem::forget(output_data);
+        Err(format!(
+            "Msg: could not generate membership key, Error: {:#?}",
+            err
+        ))
+    } else {
+        let result = Uint8Array::from(&output_data[..]);
+        std::mem::forget(output_data);
+        Ok(result)
+    }
+}
+
+#[wasm_bindgen(js_name = hash)]
+pub fn wasm_hash(input: Uint8Array, is_little_endian: bool) -> Result<Uint8Array, String> {
+    let mut output_data: Vec<u8> = Vec::new();
+    let input_data = &input.to_vec()[..];
+    if let Err(err) = hash(input_data, &mut output_data, is_little_endian) {
+        std::mem::forget(output_data);
+        Err(format!("Msg: could not generate hash, Error: {:#?}", err))
+    } else {
+        let result = Uint8Array::from(&output_data[..]);
+        std::mem::forget(output_data);
+        Ok(result)
+    }
+}
+
+#[wasm_bindgen(js_name = poseidonHash)]
+pub fn wasm_poseidon_hash(input: Uint8Array, is_little_endian: bool) -> Result<Uint8Array, String> {
+    let mut output_data: Vec<u8> = Vec::new();
+    let input_data = &input.to_vec()[..];
+    if let Err(err) = poseidon_hash(input_data, &mut output_data, is_little_endian) {
+        std::mem::forget(output_data);
+        Err(format!(
+            "Msg: could not generate poseidon hash, Error: {:#?}",
+            err
+        ))
+    } else {
+        let result = Uint8Array::from(&output_data[..]);
+        std::mem::forget(output_data);
+        Ok(result)
+    }
+}

rln-wasm-utils/tests/wasm_utils_test.rs

@@ -0,0 +1,114 @@
+#![cfg(target_arch = "wasm32")]
+
+#[cfg(test)]
+mod test {
+    use ark_std::{UniformRand, rand::thread_rng};
+    use rand::Rng;
+    use rln::circuit::Fr;
+    use rln::hashers::{ROUND_PARAMS, hash_to_field_le, poseidon_hash};
+    use rln::protocol::{
+        deserialize_identity_pair_be, deserialize_identity_pair_le, deserialize_identity_tuple_be,
+        deserialize_identity_tuple_le,
+    };
+    use rln::utils::{bytes_le_to_fr, vec_fr_to_bytes_le};
+    use rln_wasm_utils::{
+        wasm_extended_key_gen, wasm_hash, wasm_key_gen, wasm_poseidon_hash,
+        wasm_seeded_extended_key_gen, wasm_seeded_key_gen,
+    };
+    use wasm_bindgen_test::*;
+
+    #[wasm_bindgen_test]
+    fn test_wasm_key_gen() {
+        let result_le = wasm_key_gen(true);
+        assert!(result_le.is_ok());
+        deserialize_identity_pair_le(result_le.unwrap().to_vec());
+
+        let result_be = wasm_key_gen(false);
+        assert!(result_be.is_ok());
+        deserialize_identity_pair_be(result_be.unwrap().to_vec());
+    }
+
+    #[wasm_bindgen_test]
+    fn test_wasm_extended_key_gen() {
+        let result_le = wasm_extended_key_gen(true);
+        assert!(result_le.is_ok());
+        deserialize_identity_tuple_le(result_le.unwrap().to_vec());
+
+        let result_be = wasm_extended_key_gen(false);
+        assert!(result_be.is_ok());
+        deserialize_identity_tuple_be(result_be.unwrap().to_vec());
+    }
+
+    #[wasm_bindgen_test]
+    fn test_wasm_seeded_key_gen() {
+        // Create a test seed
+        let seed_data = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+        let seed = js_sys::Uint8Array::from(&seed_data[..]);
+
+        let result_le = wasm_seeded_key_gen(seed.clone(), true);
+        assert!(result_le.is_ok());
+        let fr_le = deserialize_identity_pair_le(result_le.unwrap().to_vec());
+
+        let result_be = wasm_seeded_key_gen(seed, false);
+        assert!(result_be.is_ok());
+        let fr_be = deserialize_identity_pair_be(result_be.unwrap().to_vec());
+
+        assert_eq!(fr_le, fr_be);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_wasm_seeded_extended_key_gen() {
+        // Create a test seed
+        let seed_data = vec![1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
+        let seed = js_sys::Uint8Array::from(&seed_data[..]);
+
+        let result_le = wasm_seeded_extended_key_gen(seed.clone(), true);
+        assert!(result_le.is_ok());
+        let fr_le = deserialize_identity_tuple_le(result_le.unwrap().to_vec());
+
+        let result_be = wasm_seeded_extended_key_gen(seed, false);
+        assert!(result_be.is_ok());
+        let fr_be = deserialize_identity_tuple_be(result_be.unwrap().to_vec());
+
+        assert_eq!(fr_le, fr_be);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_wasm_hash() {
+        // Create test input data
+        let signal: [u8; 32] = [0; 32];
+        let input = js_sys::Uint8Array::from(&signal[..]);
+
+        let result_le = wasm_hash(input.clone(), true);
+        assert!(result_le.is_ok());
+
+        let serialized_hash = result_le.unwrap().to_vec();
+        let (hash1, _) = bytes_le_to_fr(&serialized_hash);
+
+        let hash2 = hash_to_field_le(&signal);
+
+        assert_eq!(hash1, hash2);
+    }
+
+    #[wasm_bindgen_test]
+    fn test_wasm_poseidon_hash() {
+        let mut rng = thread_rng();
+        let number_of_inputs = rng.gen_range(1..ROUND_PARAMS.len());
+        let mut inputs = Vec::with_capacity(number_of_inputs);
+        for _ in 0..number_of_inputs {
+            inputs.push(Fr::rand(&mut rng));
+        }
+        let inputs_ser = vec_fr_to_bytes_le(&inputs);
+        let input = js_sys::Uint8Array::from(&inputs_ser[..]);
+
+        let expected_hash = poseidon_hash(inputs.as_ref());
+
+        let result_le = wasm_poseidon_hash(input.clone(), true);
+        assert!(result_le.is_ok());
+
+        let serialized_hash = result_le.unwrap().to_vec();
+        let (received_hash, _) = bytes_le_to_fr(&serialized_hash);
+
+        assert_eq!(received_hash, expected_hash);
+    }
+}

rln-wasm/.gitignore

@@ -0,0 +1,21 @@
+# Common files to ignore in Rust projects
+.DS_Store
+.idea
+*.log
+tmp/
+
+# Generated by Cargo will have compiled files and executables
+/target
+Cargo.lock
+
+# Generated by rln-wasm
+pkg/
+
+# 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-wasm/Cargo.toml

@@ -0,0 +1,47 @@
+[package]
+name = "rln-wasm"
+version = "0.2.0"
+edition = "2021"
+license = "MIT or Apache2"
+
+[lib]
+crate-type = ["cdylib", "rlib"]
+
+[dependencies]
+rln = { path = "../rln", version = "0.8.0", default-features = false, features = [
+    "stateless",
+] }
+rln-wasm-utils = { path = "../rln-wasm-utils", version = "0.1.0", default-features = false }
+zerokit_utils = { path = "../utils", version = "0.6.0", default-features = false }
+num-bigint = { version = "0.4.6", default-features = false }
+js-sys = "0.3.77"
+wasm-bindgen = "0.2.100"
+serde-wasm-bindgen = "0.6.5"
+wasm-bindgen-rayon = { version = "1.3.0", features = [
+    "no-bundler",
+], optional = true }
+
+# The `console_error_panic_xhook` 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 }
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+getrandom = { version = "0.2.16", features = ["js"] }
+
+[dev-dependencies]
+serde_json = "1.0.141"
+wasm-bindgen-test = "0.3.50"
+wasm-bindgen-futures = "0.4.50"
+
+[dev-dependencies.web-sys]
+version = "0.3.77"
+features = ["Window", "Navigator"]
+
+[features]
+default = ["console_error_panic_hook"]
+parallel = ["rln/parallel", "wasm-bindgen-rayon"]
+
+[package.metadata.docs.rs]
+all-features = true

rln-wasm/Makefile.toml

@@ -0,0 +1,99 @@
+[tasks.build]
+clear = true
+dependencies = ["pack_build", "pack_rename", "pack_resize"]
+
+[tasks.build_parallel]
+clear = true
+dependencies = ["pack_build_parallel", "pack_rename", "pack_resize"]
+
+[tasks.pack_build]
+command = "wasm-pack"
+args = ["build", "--release", "--target", "web", "--scope", "waku"]
+
+[tasks.pack_build_parallel]
+command = "env"
+args = [
+    "RUSTFLAGS=-C target-feature=+atomics,+bulk-memory,+mutable-globals",
+    "rustup",
+    "run",
+    "nightly",
+    "wasm-pack",
+    "build",
+    "--release",
+    "--target",
+    "web",
+    "--scope",
+    "waku",
+    "--features",
+    "parallel",
+    "-Z",
+    "build-std=panic_abort,std",
+]
+[tasks.pack_rename]
+script = "sed -i.bak 's/rln-wasm/zerokit-rln-wasm/g' pkg/package.json && rm pkg/package.json.bak"
+
+[tasks.pack_resize]
+command = "wasm-opt"
+args = [
+    "pkg/rln_wasm_bg.wasm",
+    "-Oz",
+    "--strip-debug",
+    "--strip-dwarf",
+    "--remove-unused-module-elements",
+    "--vacuum",
+    "-o",
+    "pkg/rln_wasm_bg.wasm",
+]
+
+[tasks.test]
+command = "wasm-pack"
+args = [
+    "test",
+    "--release",
+    "--node",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build"]
+
+[tasks.test_browser]
+command = "wasm-pack"
+args = [
+    "test",
+    "--release",
+    "--chrome",
+    "--headless",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build"]
+
+[tasks.test_parallel]
+command = "env"
+args = [
+    "RUSTFLAGS=-C target-feature=+atomics,+bulk-memory,+mutable-globals",
+    "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.bench]
+disabled = true

rln-wasm/README.md

@@ -0,0 +1,146 @@
+# RLN for WASM
+
+[![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)
+
+The Zerokit RLN WASM Module provides WebAssembly bindings for working with
+Rate-Limiting Nullifier [RLN](https://rfc.vac.dev/spec/32/) 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 Dependencies
+
+> [!NOTE]
+> This project requires the following tools:
+>
+> - `wasm-pack` - for compiling Rust to WebAssembly
+> - `cargo-make` - for running build commands
+> - `nvm` - to install and manage Node.js
+>
+> Ensure all dependencies are installed before proceeding.
+
+### Manually
+
+#### Install `wasm-pack`
+
+```bash
+cargo install wasm-pack --version=0.13.1
+```
+
+#### Install `cargo-make`
+
+```bash
+cargo install cargo-make
+```
+
+#### Install `Node.js`
+
+If you don't have `nvm` (Node Version Manager), install it by following
+the [installation instructions](https://github.com/nvm-sh/nvm?tab=readme-ov-file#install--update-script).
+
+After installing `nvm`, install and use Node.js `v22.14.0`:
+
+```bash
+nvm install 22.14.0
+nvm use 22.14.0
+nvm alias default 22.14.0
+```
+
+If you already have Node.js installed,
+check your version with `node -v` command — the version must be strictly greater than 22.
+
+### Or install everything
+
+You can run the following command from the root of the repository to install all required dependencies for `zerokit`
+
+```bash
+make installdeps
+```
+
+## Building the library
+
+First, navigate to the rln-wasm directory:
+
+```bash
+cd rln-wasm
+```
+
+Compile zerokit for `wasm32-unknown-unknown`:
+
+```bash
+cargo make build
+```
+
+## Running tests and benchmarks
+
+```bash
+cargo make test
+```
+
+If you want to run the tests in browser headless mode, you can use the following command:
+
+```bash
+cargo make test_browser
+```
+
+## Parallel computation
+
+The library supports parallel computation using the `wasm-bindgen-rayon` crate,
+enabling multi-threaded execution in the browser.
+
+> [!NOTE]
+> Parallel support is not enabled by default due to WebAssembly and browser limitations. \
+> Compiling this feature requires `nightly` Rust.
+
+### Build Setup
+
+#### Install `nightly` Rust
+
+```bash
+rustup install nightly
+```
+
+### Build Commands
+
+To enable parallel computation for WebAssembly threads, you can use the following command:
+
+```bash
+cargo make build_parallel
+```
+
+### WebAssembly Threading Support
+
+Most modern browsers support WebAssembly threads,
+but they require the following headers to enable `SharedArrayBuffer`, which is necessary for multithreading:
+
+- Cross-Origin-Opener-Policy: same-origin
+- Cross-Origin-Embedder-Policy: require-corp
+
+Without these, the application will fall back to single-threaded mode.
+
+## Feature detection
+
+If you're targeting [older browser versions that didn't support WebAssembly threads yet](https://webassembly.org/roadmap/),
+you'll likely want to create two builds - one with thread support and one without -
+and use feature detection to choose the right one on the JavaScript side.
+
+You can use [wasm-feature-detect](https://github.com/GoogleChromeLabs/wasm-feature-detect) library for this purpose.
+For example, your code might look like this:
+
+```js
+import { threads } from 'wasm-feature-detect';
+
+let wasmPkg;
+
+if (await threads()) {
+  wasmPkg = await import('./pkg-with-threads/index.js');
+  await wasmPkg.default();
+  await wasmPkg.initThreadPool(navigator.hardwareConcurrency);
+} else {
+  wasmPkg = await import('./pkg-without-threads/index.js');
+  await wasmPkg.default();
+}
+
+wasmPkg.nowCallAnyExportedFuncs();
+```

rln-wasm/resources/witness_calculator.js

@@ -0,0 +1,328 @@
+// 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;
+  try {
+    wasmModule = await WebAssembly.compile(code);
+  } catch (err) {
+    console.log(err);
+    console.log(
+      "\nTry to run circom --c in order to generate c++ code instead\n"
+    );
+    throw new Error(err);
+  }
+
+  let wc;
+
+  let errStr = "";
+  let msgStr = "";
+
+  const instance = await WebAssembly.instantiate(wasmModule, {
+    runtime: {
+      exceptionHandler: function (code) {
+        let err;
+        if (code == 1) {
+          err = "Signal not found.\n";
+        } else if (code == 2) {
+          err = "Too many signals set.\n";
+        } else if (code == 3) {
+          err = "Signal already set.\n";
+        } else if (code == 4) {
+          err = "Assert Failed.\n";
+        } else if (code == 5) {
+          err = "Not enough memory.\n";
+        } else if (code == 6) {
+          err = "Input signal array access exceeds the size.\n";
+        } else {
+          err = "Unknown error.\n";
+        }
+        throw new Error(err + errStr);
+      },
+      printErrorMessage: function () {
+        errStr += getMessage() + "\n";
+        // console.error(getMessage());
+      },
+      writeBufferMessage: function () {
+        const msg = getMessage();
+        // Any calls to `log()` will always end with a `\n`, so that's when we print and reset
+        if (msg === "\n") {
+          console.log(msgStr);
+          msgStr = "";
+        } else {
+          // If we've buffered other content, put a space in between the items
+          if (msgStr !== "") {
+            msgStr += " ";
+          }
+          // Then append the message to the message we are creating
+          msgStr += msg;
+        }
+      },
+      showSharedRWMemory: function () {
+        printSharedRWMemory();
+      },
+    },
+  });
+
+  const sanityCheck = options;
+  //        options &&
+  //        (
+  //            options.sanityCheck ||
+  //            options.logGetSignal ||
+  //            options.logSetSignal ||
+  //            options.logStartComponent ||
+  //            options.logFinishComponent
+  //        );
+
+  wc = new WitnessCalculator(instance, sanityCheck);
+  return wc;
+
+  function getMessage() {
+    var message = "";
+    var c = instance.exports.getMessageChar();
+    while (c != 0) {
+      message += String.fromCharCode(c);
+      c = instance.exports.getMessageChar();
+    }
+    return message;
+  }
+
+  function printSharedRWMemory() {
+    const shared_rw_memory_size = instance.exports.getFieldNumLen32();
+    const arr = new Uint32Array(shared_rw_memory_size);
+    for (let j = 0; j < shared_rw_memory_size; j++) {
+      arr[shared_rw_memory_size - 1 - j] =
+        instance.exports.readSharedRWMemory(j);
+    }
+
+    // If we've buffered other content, put a space in between the items
+    if (msgStr !== "") {
+      msgStr += " ";
+    }
+    // Then append the value to the message we are creating
+    msgStr += fromArray32(arr).toString();
+  }
+}
+
+class WitnessCalculator {
+  constructor(instance, sanityCheck) {
+    this.instance = instance;
+
+    this.version = this.instance.exports.getVersion();
+    this.n32 = this.instance.exports.getFieldNumLen32();
+
+    this.instance.exports.getRawPrime();
+    const arr = new Uint32Array(this.n32);
+    for (let i = 0; i < this.n32; i++) {
+      arr[this.n32 - 1 - i] = this.instance.exports.readSharedRWMemory(i);
+    }
+    this.prime = fromArray32(arr);
+
+    this.witnessSize = this.instance.exports.getWitnessSize();
+
+    this.sanityCheck = sanityCheck;
+  }
+
+  circom_version() {
+    return this.instance.exports.getVersion();
+  }
+
+  async _doCalculateWitness(input, sanityCheck) {
+    //input is assumed to be a map from signals to arrays of bigints
+    this.instance.exports.init(this.sanityCheck || sanityCheck ? 1 : 0);
+    const keys = Object.keys(input);
+    var input_counter = 0;
+    keys.forEach((k) => {
+      const h = fnvHash(k);
+      const hMSB = parseInt(h.slice(0, 8), 16);
+      const hLSB = parseInt(h.slice(8, 16), 16);
+      const fArr = flatArray(input[k]);
+      let signalSize = this.instance.exports.getInputSignalSize(hMSB, hLSB);
+      if (signalSize < 0) {
+        throw new Error(`Signal ${k} not found\n`);
+      }
+      if (fArr.length < signalSize) {
+        throw new Error(`Not enough values for input signal ${k}\n`);
+      }
+      if (fArr.length > signalSize) {
+        throw new Error(`Too many values for input signal ${k}\n`);
+      }
+      for (let i = 0; i < fArr.length; i++) {
+        const arrFr = toArray32(BigInt(fArr[i]) % this.prime, this.n32);
+        for (let j = 0; j < this.n32; j++) {
+          this.instance.exports.writeSharedRWMemory(j, arrFr[this.n32 - 1 - j]);
+        }
+        try {
+          this.instance.exports.setInputSignal(hMSB, hLSB, i);
+          input_counter++;
+        } catch (err) {
+          // console.log(`After adding signal ${i} of ${k}`)
+          throw new Error(err);
+        }
+      }
+    });
+    if (input_counter < this.instance.exports.getInputSize()) {
+      throw new Error(
+        `Not all inputs have been set. Only ${input_counter} out of ${this.instance.exports.getInputSize()}`
+      );
+    }
+  }
+
+  async calculateWitness(input, sanityCheck) {
+    const w = [];
+
+    await this._doCalculateWitness(input, sanityCheck);
+
+    for (let i = 0; i < this.witnessSize; i++) {
+      this.instance.exports.getWitness(i);
+      const arr = new Uint32Array(this.n32);
+      for (let j = 0; j < this.n32; j++) {
+        arr[this.n32 - 1 - j] = this.instance.exports.readSharedRWMemory(j);
+      }
+      w.push(fromArray32(arr));
+    }
+
+    return w;
+  }
+
+  async calculateBinWitness(input, sanityCheck) {
+    const buff32 = new Uint32Array(this.witnessSize * this.n32);
+    const buff = new Uint8Array(buff32.buffer);
+    await this._doCalculateWitness(input, sanityCheck);
+
+    for (let i = 0; i < this.witnessSize; i++) {
+      this.instance.exports.getWitness(i);
+      const pos = i * this.n32;
+      for (let j = 0; j < this.n32; j++) {
+        buff32[pos + j] = this.instance.exports.readSharedRWMemory(j);
+      }
+    }
+
+    return buff;
+  }
+
+  async calculateWTNSBin(input, sanityCheck) {
+    const buff32 = new Uint32Array(this.witnessSize * this.n32 + this.n32 + 11);
+    const buff = new Uint8Array(buff32.buffer);
+    await this._doCalculateWitness(input, sanityCheck);
+
+    //"wtns"
+    buff[0] = "w".charCodeAt(0);
+    buff[1] = "t".charCodeAt(0);
+    buff[2] = "n".charCodeAt(0);
+    buff[3] = "s".charCodeAt(0);
+
+    //version 2
+    buff32[1] = 2;
+
+    //number of sections: 2
+    buff32[2] = 2;
+
+    //id section 1
+    buff32[3] = 1;
+
+    const n8 = this.n32 * 4;
+    //id section 1 length in 64bytes
+    const idSection1length = 8 + n8;
+    const idSection1lengthHex = idSection1length.toString(16);
+    buff32[4] = parseInt(idSection1lengthHex.slice(0, 8), 16);
+    buff32[5] = parseInt(idSection1lengthHex.slice(8, 16), 16);
+
+    //this.n32
+    buff32[6] = n8;
+
+    //prime number
+    this.instance.exports.getRawPrime();
+
+    var pos = 7;
+    for (let j = 0; j < this.n32; j++) {
+      buff32[pos + j] = this.instance.exports.readSharedRWMemory(j);
+    }
+    pos += this.n32;
+
+    // witness size
+    buff32[pos] = this.witnessSize;
+    pos++;
+
+    //id section 2
+    buff32[pos] = 2;
+    pos++;
+
+    // section 2 length
+    const idSection2length = n8 * this.witnessSize;
+    const idSection2lengthHex = idSection2length.toString(16);
+    buff32[pos] = parseInt(idSection2lengthHex.slice(0, 8), 16);
+    buff32[pos + 1] = parseInt(idSection2lengthHex.slice(8, 16), 16);
+
+    pos += 2;
+    for (let i = 0; i < this.witnessSize; i++) {
+      this.instance.exports.getWitness(i);
+      for (let j = 0; j < this.n32; j++) {
+        buff32[pos + j] = this.instance.exports.readSharedRWMemory(j);
+      }
+      pos += this.n32;
+    }
+
+    return buff;
+  }
+}
+
+function toArray32(rem, size) {
+  const res = []; //new Uint32Array(size); //has no unshift
+  const radix = BigInt(0x100000000);
+  while (rem) {
+    res.unshift(Number(rem % radix));
+    rem = rem / radix;
+  }
+  if (size) {
+    var i = size - res.length;
+    while (i > 0) {
+      res.unshift(0);
+      i--;
+    }
+  }
+  return res;
+}
+
+function fromArray32(arr) {
+  //returns a BigInt
+  var res = BigInt(0);
+  const radix = BigInt(0x100000000);
+  for (let i = 0; i < arr.length; i++) {
+    res = res * radix + BigInt(arr[i]);
+  }
+  return res;
+}
+
+function flatArray(a) {
+  var res = [];
+  fillArray(res, a);
+  return res;
+
+  function fillArray(res, a) {
+    if (Array.isArray(a)) {
+      for (let i = 0; i < a.length; i++) {
+        fillArray(res, a[i]);
+      }
+    } else {
+      res.push(a);
+    }
+  }
+}
+
+function fnvHash(str) {
+  const uint64_max = BigInt(2) ** BigInt(64);
+  let hash = BigInt("0xCBF29CE484222325");
+  for (var i = 0; i < str.length; i++) {
+    hash ^= BigInt(str[i].charCodeAt());
+    hash *= BigInt(0x100000001b3);
+    hash %= uint64_max;
+  }
+  let shash = hash.toString(16);
+  let n = 16 - shash.length;
+  shash = "0".repeat(n).concat(shash);
+  return shash;
+}

rln-wasm/src/lib.rs

@@ -0,0 +1,212 @@
+#![cfg(target_arch = "wasm32")]
+
+use js_sys::{BigInt as JsBigInt, Object, Uint8Array};
+use num_bigint::BigInt;
+use rln::public::RLN;
+use std::vec::Vec;
+use wasm_bindgen::prelude::*;
+
+#[cfg(feature = "parallel")]
+pub use wasm_bindgen_rayon::init_thread_pool;
+
+#[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))
+        }
+    }
+}
+
+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 = 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()[..]
+    )
+}

rln-wasm/tests/browser.rs

@@ -0,0 +1,266 @@
+#![cfg(target_arch = "wasm32")]
+
+#[cfg(test)]
+mod tests {
+    use js_sys::{BigInt as JsBigInt, Date, Object, Uint8Array};
+    use rln::circuit::{Fr, TEST_TREE_DEPTH};
+    use rln::hashers::{hash_to_field_le, poseidon_hash, PoseidonHash};
+    use rln::protocol::{prepare_verify_input, rln_witness_from_values, serialize_witness};
+    use rln::utils::{bytes_le_to_fr, fr_to_bytes_le, IdSecret};
+    use rln_wasm::{
+        wasm_generate_rln_proof_with_witness, wasm_new, wasm_rln_witness_to_json,
+        wasm_verify_with_roots,
+    };
+    use rln_wasm_utils::wasm_key_gen;
+    use wasm_bindgen::{prelude::wasm_bindgen, JsValue};
+    use wasm_bindgen_test::{console_log, wasm_bindgen_test, wasm_bindgen_test_configure};
+    use zerokit_utils::{
+        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_30/rln_final.arkzkey");
+
+    const CIRCOM_BYTES: &[u8] = include_bytes!("../../rln/resources/tree_depth_30/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().expect("Failed to check thread pool support") {
+            panic!("Thread pool is NOT supported");
+        } else {
+            // Initialize thread pool
+            let cpu_count = window()
+                .expect("Failed to get window")
+                .navigator()
+                .hardware_concurrency() as usize;
+            JsFuture::from(init_thread_pool(cpu_count))
+                .await
+                .expect("Failed to initialize thread pool");
+        }
+
+        // Initialize witness calculator
+        initWitnessCalculator(WITNESS_CALCULATOR_JS)
+            .expect("Failed to initialize witness calculator");
+
+        let mut results = String::from("\nbenchmarks:\n");
+        let iterations = 10;
+
+        let zkey = readFile(&ARKZKEY_BYTES).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: OptimalMerkleTree<PoseidonHash> =
+            OptimalMerkleTree::default(TEST_TREE_DEPTH).expect("Failed to create tree");
+
+        // Benchmark wasm_key_gen
+        let start_wasm_key_gen = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_key_gen(true).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(true).expect("Failed to generate keys");
+        let id_key = mem_keys.subarray(0, 32);
+        let (identity_secret_hash, _) = IdSecret::from_bytes_le(&id_key.to_vec());
+        let (id_commitment, _) = bytes_le_to_fr(&mem_keys.subarray(32, 64).to_vec());
+
+        let epoch = hash_to_field_le(b"test-epoch");
+        let rln_identifier = hash_to_field_le(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_le(&signal);
+
+        let merkle_proof: OptimalMerkleProof<PoseidonHash> = tree
+            .proof(identity_index)
+            .expect("Failed to generate merkle proof");
+
+        let rln_witness = rln_witness_from_values(
+            identity_secret_hash,
+            merkle_proof.get_path_elements(),
+            merkle_proof.get_path_index(),
+            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_BYTES, 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_BYTES, 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
+        console_log!("{results}");
+    }
+}

rln-wasm/tests/node.rs

@@ -0,0 +1,247 @@
+#![cfg(not(feature = "parallel"))]
+#![cfg(target_arch = "wasm32")]
+
+#[cfg(test)]
+mod tests {
+    use js_sys::{BigInt as JsBigInt, Date, Object, Uint8Array};
+    use rln::circuit::{Fr, TEST_TREE_DEPTH};
+    use rln::hashers::{hash_to_field_le, poseidon_hash, PoseidonHash};
+    use rln::protocol::{prepare_verify_input, rln_witness_from_values, serialize_witness};
+    use rln::utils::{bytes_le_to_fr, fr_to_bytes_le, IdSecret};
+    use rln_wasm::{
+        wasm_generate_rln_proof_with_witness, wasm_new, wasm_rln_witness_to_json,
+        wasm_verify_with_roots,
+    };
+    use rln_wasm_utils::wasm_key_gen;
+    use wasm_bindgen::{prelude::wasm_bindgen, JsValue};
+    use wasm_bindgen_test::{console_log, wasm_bindgen_test};
+    use zerokit_utils::{
+        OptimalMerkleProof, OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree,
+    };
+
+    const WITNESS_CALCULATOR_JS: &str = include_str!("../resources/witness_calculator.js");
+
+    #[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.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 ARKZKEY_PATH: &str = "../rln/resources/tree_depth_30/rln_final.arkzkey";
+
+    const CIRCOM_PATH: &str = "../rln/resources/tree_depth_30/rln.wasm";
+
+    #[wasm_bindgen_test]
+    pub async fn rln_wasm_benchmark() {
+        // Initialize witness calculator
+        initWitnessCalculator(WITNESS_CALCULATOR_JS)
+            .expect("Failed to initialize witness calculator");
+
+        let mut results = String::from("\nbenchmarks:\n");
+        let iterations = 10;
+
+        let zkey = readFile(&ARKZKEY_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: OptimalMerkleTree<PoseidonHash> =
+            OptimalMerkleTree::default(TEST_TREE_DEPTH).expect("Failed to create tree");
+
+        // Benchmark wasm_key_gen
+        let start_wasm_key_gen = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_key_gen(true).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(true).expect("Failed to generate keys");
+        let id_key = mem_keys.subarray(0, 32);
+        let (identity_secret_hash, _) = IdSecret::from_bytes_le(&id_key.to_vec());
+        let (id_commitment, _) = bytes_le_to_fr(&mem_keys.subarray(32, 64).to_vec());
+
+        let epoch = hash_to_field_le(b"test-epoch");
+        let rln_identifier = hash_to_field_le(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_le(&signal);
+
+        let merkle_proof: OptimalMerkleProof<PoseidonHash> = tree
+            .proof(identity_index)
+            .expect("Failed to generate merkle proof");
+
+        let rln_witness = rln_witness_from_values(
+            identity_secret_hash,
+            merkle_proof.get_path_elements(),
+            merkle_proof.get_path_index(),
+            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!(
+            "calculate_witness: {}\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
+        console_log!("{results}");
+    }
+}

rln/Cargo.toml

@@ -1,42 +1,85 @@
 [package]
 name = "rln"
-version = "0.1.0"
+version = "0.8.0"
 edition = "2021"
+license = "MIT OR Apache-2.0"
+description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
+documentation = "https://github.com/vacp2p/zerokit"
+homepage = "https://vac.dev"
+repository = "https://github.com/vacp2p/zerokit"
 
 [lib]
-crate-type = ["cdylib", "rlib", "staticlib"]
+crate-type = ["rlib", "staticlib", "cdylib"]
+bench = false
+
+# This flag disable cargo doctests, i.e. testing example code-snippets in documentation
+doctest = false
 
 [dependencies]
-
 # ZKP Generation
-ark-ff = { version = "0.3.0", default-features = false, features = ["parallel", "asm"] }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-bn254 = { version = "0.3.0" }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-ark-relations = { version = "0.3.0", default-features = false, features = [ "std" ] }
-ark-serialize = { version = "0.3.0", default-features = false }
-ark-circom = { git = "https://github.com/gakonst/ark-circom", rev = "06eb075", features = ["circom-2"] }
-#ark-circom = { git = "https://github.com/vacp2p/ark-circom", branch = "no-ethers-core", features = ["circom-2"] }
-wasmer = "2.3.0"
+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 }
+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 }
 
 # error handling
-color-eyre = "0.5.11"
-thiserror = "1.0.0"
+thiserror = "2.0.12"
 
 # utilities
+rayon = { version = "1.10.0", optional = true }
+byteorder = "1.5.0"
 cfg-if = "1.0"
-num-bigint = { version = "0.4.3", default-features = false, features = ["rand"] }
-num-traits = "0.2.11"
-once_cell = "1.14.0"
-rand = "0.8"
+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 = "1.15.0", features = ["rand", "serde", "ark-ff-04"] }
 tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+zeroize = "1.8"
+tempfile = "3.21.0"
+utils = { package = "zerokit_utils", version = "0.6.0", path = "../utils", default-features = false }
 
 # serialization
-serde_json = "1.0.48"
+prost = "0.14.1"
+serde_json = "1.0.141"
+serde = { version = "1.0", features = ["derive"] }
+
+document-features = { version = "0.2.11", optional = true }
 
 [dev-dependencies]
-
-hex-literal = "0.3.4"
+criterion = { version = "0.7.0", features = ["html_reports"] }
 
 [features]
-fullmerkletree = []
+default = ["parallel", "pmtree-ft"]
+stateless = []
+parallel = [
+    "rayon",
+    "utils/parallel",
+    "ark-ff/parallel",
+    "ark-ec/parallel",
+    "ark-std/parallel",
+    "ark-poly/parallel",
+    "ark-groth16/parallel",
+    "ark-serialize/parallel",
+]
+fullmerkletree = [] # Pre-allocated tree, fastest access
+optimalmerkletree = [] # Sparse storage, memory efficient
+pmtree-ft = ["utils/pmtree-ft"] # Persistent storage, disk-based
+
+[[bench]]
+name = "pmtree_benchmark"
+harness = false
+required-features = ["pmtree-ft"]
+
+[[bench]]
+name = "poseidon_tree_benchmark"
+harness = false
+
+[package.metadata.docs.rs]
+all-features = true

rln/Makefile.toml

@@ -0,0 +1,15 @@
+[tasks.build]
+command = "cargo"
+args = ["build", "--release"]
+
+[tasks.test]
+command = "cargo"
+args = ["test", "--release", "--", "--nocapture"]
+
+[tasks.test_stateless]
+command = "cargo"
+args = ["test", "--release", "--no-default-features", "--features", "stateless"]
+
+[tasks.bench]
+command = "cargo"
+args = ["bench"]

rln/README.md

@@ -1,43 +1,334 @@
 # Zerokit RLN Module
 
-This module provides APIs to manage, compute and verify [RLN](https://rfc.vac.dev/spec/32/) zkSNARK proofs and RLN primitives.
+[![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)
 
-Currently, this module comes with three [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) RLN circuits having Merkle tree of height `15`, `19` and `20`, respectively.
+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:
 
-Implemented tests can be executed by running within the module folder
+- Generate and verify RLN proofs
+- Work with Merkle trees for commitment storage
+- Implement rate-limiting mechanisms for distributed systems
 
-`cargo test --release`
+## Quick Start
 
-## Compiling circuits
+> [!IMPORTANT]
+> 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.
 
-`rln` (https://github.com/privacy-scaling-explorations/rln) repo with Circuits is contained as a submodule. 
+### Add RLN as dependency
 
-``` sh
-# Update submodules
-git submodule update --init --recursive
+We start by adding zerokit RLN to our `Cargo.toml`
 
-# Install rln dependencies
-cd vendor/rln/ && npm install
+```toml
+[dependencies]
+rln = { git = "https://github.com/vacp2p/zerokit" }
+```
+
+## Basic Usage Example
+
+The RLN object constructor requires the following files:
+
+- `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.
+
+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.
+
+```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;
+
+fn main() {
+    // 1. Initialize RLN with parameters:
+    // - the tree depth;
+    // - the tree config, if it is not defined, the default value will be set
+    let tree_depth = 30;
+    let input = Cursor::new(json!({}).to_string());
+    let mut rln = RLN::new(tree_depth, input).unwrap();
+
+    // 2. Generate an identity keypair
+    let (identity_secret_hash, id_commitment) = keygen();
+
+    // 3. Add a rate commitment to the Merkle tree
+    let id_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();
+
+    // 4. 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");
+    // 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
+    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,
+        user_message_limit,
+        message_id,
+        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();
+
+    // 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
+    assert!(verified);
+}
+```
+
+### Comments for the code above for point 4
+
+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.
+
+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
+
+- **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
+
+### Prerequisites
+
+```sh
+git clone https://github.com/vacp2p/zerokit.git
+make installdeps
+cd zerokit/rln
+```
+
+### Build Commands
+
+```sh
+# Build with default features
+cargo make build
+
+# Test with default features
+cargo make test
+
+# 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.
+If you want to compile your own RLN circuit, you can follow the instructions below.
+
+### 1. Compile ZK Circuits for getting the zkey file
+
+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`:
+
+```circom
+pragma circom 2.1.0;
+include "./rln.circom";
+component main { public [x, externalNullifier] } = RLN(N, M);
+```
+
+Where:
+
+- `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 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`.
+
+```sh
+# Clone the circom repository
+git clone https://github.com/iden3/circom.git
+
+# Checkout the specific version
+cd circom && git checkout v2.1.0
+
+# Build the circom compiler
+cargo build --release
+
+# Install the circom binary globally
+cargo install --path circom
+
+# Check the circom version to ensure it's v2.1.0
+circom --version
+```
+
+#### Generate the zkey and verification key files example
+
+```sh
+# Clone the circom-rln repository
+git clone https://github.com/rate-limiting-nullifier/circom-rln
+
+# Install dependencies
+cd circom-rln && npm install
 
 # Build circuits
 ./scripts/build-circuits.sh rln
 
-# Copy over assets
-cp build/zkeyFiles/rln-final.zkey ../../resources/tree_height_15
-cp build/zkeyFiles/rln.wasm ../../resources/tree_height_15
+# Use the generated zkey file in subsequent steps
+cp zkeyFiles/rln/final.zkey <path_to_rln_final.zkey>
 ```
 
-Note that the above code snippet will compile a RLN circuit with a Merkle tree of height equal `15` based on the default value set in `rln/circuit/rln.circom`.
+### 2. Generate Witness Calculation Graph
 
-To compile a RLN circuit with Merkle tree height `N`, it suffices to change `rln/circuit/rln.circom` to
+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.
 
-```
-pragma circom 2.0.0;
+```sh
+# Clone the circom-witnesscalc repository
+git clone https://github.com/iden3/circom-witnesscalc
 
-include "./rln-base.circom";
+# Load the submodules
+cd circom-witnesscalc && git submodule update --init --recursive
 
-component main {public [x, epoch, rln_identifier ]} = RLN(N);
+# Build the circom-witnesscalc tool
+cargo build
+
+# Generate the witness calculation graph
+cargo run --package circom_witnesscalc --bin build-circuit ../circom-rln/circuits/rln.circom <path_to_graph.bin>
 ```
 
-However, if `N` is too big, this might require a bigger 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.
+The `rln` module comes with [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources)
+execution graph files for the RLN circuit.
+
+### 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 arkzkey support.
+
+```sh
+# Clone the ark-zkey repository
+git clone https://github.com/seemenkina/ark-zkey.git
+
+# Build the ark-zkey tool
+cd ark-zkey && cargo build
+
+# Generate the arkzkey representation for the zkey file
+cargo run --bin arkzkey-util <path_to_rln_final.zkey>
+```
+
+This will generate the `rln_final.arkzkey` file, which is used by the `rln` module.
+
+Currently, the `rln` module comes with
+[pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) arkzkey keys for the RLN circuit.
+
+> [!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
+
+Run the script as follows:
+
+```sh
+chmod +x ./convert_zkey.sh
+./convert_zkey.sh <path_to_rln_final.zkey>
+```
+
+## Get 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
+
+```rust
+cargo doc --no-deps
+```
+
+and look at unit tests to have an hint on how to interface and use them.
+
+## Detailed Protocol Flow
+
+1. **Identity Creation**: Generate a secret key and commitment
+2. **Rate Commitment**: Add commitment to a Merkle tree
+3. **External Nullifier Setup**: Combine epoch and application identifier
+4. **Proof Generation**: Create a zkSNARK proof that:
+   - Proves membership in the Merkle tree
+   - 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
+
+## Getting Involved
+
+- 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
+- [GitHub repository](https://github.com/vacp2p/zerokit) for the latest updates

rln/benches/pmtree_benchmark.rs

@@ -0,0 +1,50 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use rln::{circuit::Fr, pm_tree_adapter::PmTree};
+use utils::ZerokitMerkleTree;
+
+pub fn pmtree_benchmark(c: &mut Criterion) {
+    let mut tree = PmTree::default(2).unwrap();
+
+    let leaves: Vec<Fr> = (0..4).map(Fr::from).collect();
+
+    c.bench_function("Pmtree::set", |b| {
+        b.iter(|| {
+            tree.set(0, leaves[0]).unwrap();
+        })
+    });
+
+    c.bench_function("Pmtree:delete", |b| {
+        b.iter(|| {
+            tree.delete(0).unwrap();
+        })
+    });
+
+    c.bench_function("Pmtree::override_range", |b| {
+        b.iter(|| {
+            tree.override_range(0, leaves.clone().into_iter(), [0, 1, 2, 3].into_iter())
+                .unwrap();
+        })
+    });
+
+    c.bench_function("Pmtree::get", |b| {
+        b.iter(|| {
+            tree.get(0).unwrap();
+        })
+    });
+
+    // check intermediate node getter which required additional computation of sub root index
+    c.bench_function("Pmtree::get_subtree_root", |b| {
+        b.iter(|| {
+            tree.get_subtree_root(1, 0).unwrap();
+        })
+    });
+
+    c.bench_function("Pmtree::get_empty_leaves_indices", |b| {
+        b.iter(|| {
+            tree.get_empty_leaves_indices();
+        })
+    });
+}
+
+criterion_group!(benches, pmtree_benchmark);
+criterion_main!(benches);

rln/benches/poseidon_tree_benchmark.rs

@@ -0,0 +1,79 @@
+use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
+use rln::{
+    circuit::{Fr, TEST_TREE_DEPTH},
+    hashers::PoseidonHash,
+};
+use utils::{FullMerkleTree, OptimalMerkleTree, ZerokitMerkleTree};
+
+pub fn get_leaves(n: u32) -> Vec<Fr> {
+    (0..n).map(Fr::from).collect()
+}
+
+pub fn optimal_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
+    c.bench_function("OptimalMerkleTree::<Poseidon>::full_depth_gen", |b| {
+        b.iter(|| {
+            OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_DEPTH).unwrap();
+        })
+    });
+
+    let mut group = c.benchmark_group("Set");
+    for &n in [1u32, 10, 100].iter() {
+        let leaves = get_leaves(n);
+
+        let mut tree = OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_DEPTH).unwrap();
+        group.bench_function(
+            BenchmarkId::new("OptimalMerkleTree::<Poseidon>::set", n),
+            |b| {
+                b.iter(|| {
+                    for (i, l) in leaves.iter().enumerate() {
+                        let _ = tree.set(i, *l);
+                    }
+                })
+            },
+        );
+
+        group.bench_function(
+            BenchmarkId::new("OptimalMerkleTree::<Poseidon>::set_range", n),
+            |b| b.iter(|| tree.set_range(0, leaves.iter().cloned())),
+        );
+    }
+    group.finish();
+}
+
+pub fn full_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
+    c.bench_function("FullMerkleTree::<Poseidon>::full_depth_gen", |b| {
+        b.iter(|| {
+            FullMerkleTree::<PoseidonHash>::default(TEST_TREE_DEPTH).unwrap();
+        })
+    });
+
+    let mut group = c.benchmark_group("Set");
+    for &n in [1u32, 10, 100].iter() {
+        let leaves = get_leaves(n);
+
+        let mut tree = FullMerkleTree::<PoseidonHash>::default(TEST_TREE_DEPTH).unwrap();
+        group.bench_function(
+            BenchmarkId::new("FullMerkleTree::<Poseidon>::set", n),
+            |b| {
+                b.iter(|| {
+                    for (i, l) in leaves.iter().enumerate() {
+                        let _ = tree.set(i, *l);
+                    }
+                })
+            },
+        );
+
+        group.bench_function(
+            BenchmarkId::new("FullMerkleTree::<Poseidon>::set_range", n),
+            |b| b.iter(|| tree.set_range(0, leaves.iter().cloned())),
+        );
+    }
+    group.finish();
+}
+
+criterion_group!(
+    benches,
+    optimal_merkle_tree_poseidon_benchmark,
+    full_merkle_tree_poseidon_benchmark
+);
+criterion_main!(benches);

rln/convert_zkey.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+
+# Convert zkey to arkzkey using /tmp directory
+# Usage: ./convert.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

rln/resources/tree_height_19/verification_key.json

@@ -1,119 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 6,
- "vk_alpha_1": [
-  "1805378556360488226980822394597799963030511477964155500103132920745199284516",
-  "11990395240534218699464972016456017378439762088320057798320175886595281336136",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "11031529986141021025408838211017932346992429731488270384177563837022796743627",
-   "16042159910707312759082561183373181639420894978640710177581040523252926273854"
-  ],
-  [
-   "20112698439519222240302944148895052359035104222313380895334495118294612255131",
-   "19441583024670359810872018179190533814486480928824742448673677460151702019379"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "1342791402398183550129987853701397066695422166542200371137242980909975744720",
-   "19885954793721639146517398722913034453263197732511169431324269951156805454588"
-  ],
-  [
-   "16612518449808520746616592899100682320852224744311197908486719118388461103870",
-   "13039435290897389787786546960964558630619663289413586834851804020863949546009"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "5151991366823434428398919091000210787450832786814248297320989361921939794156",
-    "15735191313289001022885148627913534790382722933676436876510746491415970766821"
-   ],
-   [
-    "3387907257437913904447588318761906430938415556102110876587455322225272831272",
-    "1998779853452712881084781956683721603875246565720647583735935725110674288056"
-   ],
-   [
-    "14280074182991498185075387990446437410077692353432005297922275464876153151820",
-    "17092408446352310039633488224969232803092763095456307462247653153107223117633"
-   ]
-  ],
-  [
-   [
-    "4359046709531668109201634396816565829237358165496082832279660960675584351266",
-    "4511888308846208349307186938266411423935335853916317436093178288331845821336"
-   ],
-   [
-    "11429499807090785857812316277335883295048773373068683863667725283965356423273",
-    "16232274853200678548795010078253506586114563833318973594428907292096178657392"
-   ],
-   [
-    "18068999605870933925311275504102553573815570223888590384919752303726860800970",
-    "17309569111965782732372130116757295842160193489132771344011460471298173784984"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "15907620619058468322652190166474219459106695372760190199814463422116003944385",
-   "15752765921940703867480319151728055971288798043197983667046402260506178676501",
-   "1"
-  ],
-  [
-   "12004081423498474638814710157503496372594892372197913146719480190853290407272",
-   "17759993271504587923309435837545182941635937261719294500288793819648071033469",
-   "1"
-  ],
-  [
-   "878120019311612655450010384994897394984265086410869146105626241891073100410",
-   "17631186298933191134732246976686754514124819009836710500647157641262968661294",
-   "1"
-  ],
-  [
-   "14710016919630225372037989028011020715054625029990218653012745498368446893907",
-   "2581293501049347486538806758240731445964309309490885835380825245889909387041",
-   "1"
-  ],
-  [
-   "766327921864693063481261933507417084013182964450768912480746815296334678928",
-   "18104222034822903557262264275808261481286672296559910954337205847153944954509",
-   "1"
-  ],
-  [
-   "8877686447180479408315100041907552504213694351585462004774320248566787828012",
-   "15836202093850379814510995758762098170932781831518064786308541653541698178373",
-   "1"
-  ],
-  [
-   "19567388833538990982537236781224917793757180861915757860561618079730704818311",
-   "3535132838196675082818592669173684593624477421910576112671761297886253127546",
-   "1"
-  ]
- ]
-}

rln/resources/tree_height_20/verification_key.json

@@ -1,119 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 6,
- "vk_alpha_1": [
-  "1805378556360488226980822394597799963030511477964155500103132920745199284516",
-  "11990395240534218699464972016456017378439762088320057798320175886595281336136",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "11031529986141021025408838211017932346992429731488270384177563837022796743627",
-   "16042159910707312759082561183373181639420894978640710177581040523252926273854"
-  ],
-  [
-   "20112698439519222240302944148895052359035104222313380895334495118294612255131",
-   "19441583024670359810872018179190533814486480928824742448673677460151702019379"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "1948496782571164085469528023647105317580208688174386157591917599801657832035",
-   "20445814069256658101339037520922621162739470138213615104905368409238414511981"
-  ],
-  [
-   "10024680869920840984813249386422727863826862577760330492647062850849851925340",
-   "10512156247842686783409460795717734694774542185222602679117887145206209285142"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "5151991366823434428398919091000210787450832786814248297320989361921939794156",
-    "15735191313289001022885148627913534790382722933676436876510746491415970766821"
-   ],
-   [
-    "3387907257437913904447588318761906430938415556102110876587455322225272831272",
-    "1998779853452712881084781956683721603875246565720647583735935725110674288056"
-   ],
-   [
-    "14280074182991498185075387990446437410077692353432005297922275464876153151820",
-    "17092408446352310039633488224969232803092763095456307462247653153107223117633"
-   ]
-  ],
-  [
-   [
-    "4359046709531668109201634396816565829237358165496082832279660960675584351266",
-    "4511888308846208349307186938266411423935335853916317436093178288331845821336"
-   ],
-   [
-    "11429499807090785857812316277335883295048773373068683863667725283965356423273",
-    "16232274853200678548795010078253506586114563833318973594428907292096178657392"
-   ],
-   [
-    "18068999605870933925311275504102553573815570223888590384919752303726860800970",
-    "17309569111965782732372130116757295842160193489132771344011460471298173784984"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "18693301901828818437917730940595978397160482710354161265484535387752523310572",
-   "17985273354976640088538673802000794244421192643855111089693820179790551470769",
-   "1"
-  ],
-  [
-   "21164641723988537620541455173278629777250883365474191521194244273980931825942",
-   "998385854410718613441067082771678946155853656328717326195057262123686425518",
-   "1"
-  ],
-  [
-   "21666968581672145768705229094968410656430989593283335488162701230986314747515",
-   "17996457608540683483506630273632100555125353447506062045735279661096094677264",
-   "1"
-  ],
-  [
-   "20137761979695192602424300886442379728165712610493092740175904438282083668117",
-   "19184814924890679891263780109959113289320127263583260218200636509492157834679",
-   "1"
-  ],
-  [
-   "10943171273393803842589314082509655332154393332394322726077270895078286354146",
-   "10872472035685319847811233167729172672344935625121511932198535224727331126439",
-   "1"
-  ],
-  [
-   "13049169779481227658517545034348883391527506091990880778783387628208561946597",
-   "10083689369261379027228809473568899816311684698866922944902456565434209079955",
-   "1"
-  ],
-  [
-   "19633516378466409167014413361365552102431118630694133723053441455184566611083",
-   "8059525100726933978719058611146131904598011633549012007359165766216730722269",
-   "1"
-  ]
- ]
-}

rln/src/circuit.rs

@@ -1,239 +0,0 @@
-// This crate provides interfaces for the zero-knowledge circuit and keys
-
-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_circom::{read_zkey, WitnessCalculator};
-use ark_groth16::{ProvingKey, VerifyingKey};
-use ark_relations::r1cs::ConstraintMatrices;
-use num_bigint::BigUint;
-use once_cell::sync::OnceCell;
-use serde_json::Value;
-use std::fs::File;
-use std::io::{Cursor, Error, ErrorKind, Result};
-use std::path::Path;
-use std::str::FromStr;
-use std::sync::Mutex;
-use wasmer::{Module, Store};
-
-const ZKEY_FILENAME: &str = "rln_final.zkey";
-const VK_FILENAME: &str = "verifying_key.json";
-const WASM_FILENAME: &str = "rln.wasm";
-
-// These parameters are used for tests
-// Note that the circuit and keys in TEST_RESOURCES_FOLDER are compiled for Merkle trees of height 15, 19 and 20
-// Changing these parameters to other values than these defaults will cause zkSNARK proof verification to fail
-pub const TEST_PARAMETERS_INDEX: usize = 2;
-pub const TEST_TREE_HEIGHT: usize = [15, 19, 20][TEST_PARAMETERS_INDEX];
-pub const TEST_RESOURCES_FOLDER: &str = [
-    "./resources/tree_height_15/",
-    "./resources/tree_height_19/",
-    "./resources/tree_height_20/",
-][TEST_PARAMETERS_INDEX];
-
-// 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
-pub type Curve = Bn254;
-pub type Fr = ArkFr;
-pub type Fq = ArkFq;
-pub type Fq2 = ArkFq2;
-pub type G1Affine = ArkG1Affine;
-pub type G1Projective = ArkG1Projective;
-pub type G2Affine = ArkG2Affine;
-pub type G2Projective = ArkG2Projective;
-
-// Loads the proving key using a bytes vector
-pub fn zkey_from_raw(zkey_data: &Vec<u8>) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
-    if !zkey_data.is_empty() {
-        let mut c = Cursor::new(zkey_data);
-        let proving_key_and_matrices = read_zkey(&mut c)?;
-        Ok(proving_key_and_matrices)
-    } else {
-        Err(Error::new(ErrorKind::NotFound, "No proving key found!"))
-    }
-}
-
-// Loads the proving key
-pub fn zkey_from_folder(
-    resources_folder: &str,
-) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
-    let zkey_path = format!("{resources_folder}{ZKEY_FILENAME}");
-    if Path::new(&zkey_path).exists() {
-        let mut file = File::open(&zkey_path)?;
-        let proving_key_and_matrices = read_zkey(&mut file)?;
-        Ok(proving_key_and_matrices)
-    } else {
-        Err(Error::new(ErrorKind::NotFound, "No proving key found!"))
-    }
-}
-
-// Loads the verification key from a bytes vector
-pub fn vk_from_raw(vk_data: &Vec<u8>, zkey_data: &Vec<u8>) -> Result<VerifyingKey<Curve>> {
-    let verifying_key: VerifyingKey<Curve>;
-
-    if !vk_data.is_empty() {
-        verifying_key = vk_from_vector(vk_data);
-        Ok(verifying_key)
-    } else if !zkey_data.is_empty() {
-        let (proving_key, _matrices) = zkey_from_raw(zkey_data)?;
-        verifying_key = proving_key.vk;
-        Ok(verifying_key)
-    } else {
-        Err(Error::new(
-            ErrorKind::NotFound,
-            "No proving/verification key found!",
-        ))
-    }
-}
-
-// Loads the verification key
-pub fn vk_from_folder(resources_folder: &str) -> Result<VerifyingKey<Curve>> {
-    let vk_path = format!("{resources_folder}{VK_FILENAME}");
-    let zkey_path = format!("{resources_folder}{ZKEY_FILENAME}");
-
-    let verifying_key: VerifyingKey<Curve>;
-
-    if Path::new(&vk_path).exists() {
-        verifying_key = vk_from_json(&vk_path);
-        Ok(verifying_key)
-    } else if Path::new(&zkey_path).exists() {
-        let (proving_key, _matrices) = zkey_from_folder(resources_folder)?;
-        verifying_key = proving_key.vk;
-        Ok(verifying_key)
-    } else {
-        Err(Error::new(
-            ErrorKind::NotFound,
-            "No proving/verification key found!",
-        ))
-    }
-}
-
-static WITNESS_CALCULATOR: OnceCell<Mutex<WitnessCalculator>> = OnceCell::new();
-
-// Initializes the witness calculator using a bytes vector
-pub fn circom_from_raw(wasm_buffer: Vec<u8>) -> &'static Mutex<WitnessCalculator> {
-    WITNESS_CALCULATOR.get_or_init(|| {
-        let store = Store::default();
-        let module = Module::new(&store, wasm_buffer).unwrap();
-        let result =
-            WitnessCalculator::from_module(module).expect("Failed to create witness calculator");
-        Mutex::new(result)
-    })
-}
-
-// Initializes the witness calculator
-pub fn circom_from_folder(resources_folder: &str) -> &'static Mutex<WitnessCalculator> {
-    // We read the wasm file
-    let wasm_path = format!("{resources_folder}{WASM_FILENAME}");
-    let wasm_buffer = std::fs::read(&wasm_path).unwrap();
-    circom_from_raw(wasm_buffer)
-}
-
-// The following function implementations are taken/adapted from https://github.com/gakonst/ark-circom/blob/1732e15d6313fe176b0b1abb858ac9e095d0dbd7/src/zkey.rs
-
-// Utilities to convert a json verification key in a groth16::VerificationKey
-fn fq_from_str(s: &str) -> Fq {
-    Fq::try_from(BigUint::from_str(s).unwrap()).unwrap()
-}
-
-// Extracts the element in G1 corresponding to its JSON serialization
-fn json_to_g1(json: &Value, key: &str) -> G1Affine {
-    let els: Vec<String> = json
-        .get(key)
-        .unwrap()
-        .as_array()
-        .unwrap()
-        .iter()
-        .map(|i| i.as_str().unwrap().to_string())
-        .collect();
-    G1Affine::from(G1Projective::new(
-        fq_from_str(&els[0]),
-        fq_from_str(&els[1]),
-        fq_from_str(&els[2]),
-    ))
-}
-
-// Extracts the vector of G1 elements corresponding to its JSON serialization
-fn json_to_g1_vec(json: &Value, key: &str) -> Vec<G1Affine> {
-    let els: Vec<Vec<String>> = json
-        .get(key)
-        .unwrap()
-        .as_array()
-        .unwrap()
-        .iter()
-        .map(|i| {
-            i.as_array()
-                .unwrap()
-                .iter()
-                .map(|x| x.as_str().unwrap().to_string())
-                .collect::<Vec<String>>()
-        })
-        .collect();
-
-    els.iter()
-        .map(|coords| {
-            G1Affine::from(G1Projective::new(
-                fq_from_str(&coords[0]),
-                fq_from_str(&coords[1]),
-                fq_from_str(&coords[2]),
-            ))
-        })
-        .collect()
-}
-
-// Extracts the element in G2 corresponding to its JSON serialization
-fn json_to_g2(json: &Value, key: &str) -> G2Affine {
-    let els: Vec<Vec<String>> = json
-        .get(key)
-        .unwrap()
-        .as_array()
-        .unwrap()
-        .iter()
-        .map(|i| {
-            i.as_array()
-                .unwrap()
-                .iter()
-                .map(|x| x.as_str().unwrap().to_string())
-                .collect::<Vec<String>>()
-        })
-        .collect();
-
-    let x = Fq2::new(fq_from_str(&els[0][0]), fq_from_str(&els[0][1]));
-    let y = Fq2::new(fq_from_str(&els[1][0]), fq_from_str(&els[1][1]));
-    let z = Fq2::new(fq_from_str(&els[2][0]), fq_from_str(&els[2][1]));
-    G2Affine::from(G2Projective::new(x, y, z))
-}
-
-// Converts JSON to a VerifyingKey
-fn to_verifying_key(json: serde_json::Value) -> VerifyingKey<Curve> {
-    VerifyingKey {
-        alpha_g1: json_to_g1(&json, "vk_alpha_1"),
-        beta_g2: json_to_g2(&json, "vk_beta_2"),
-        gamma_g2: json_to_g2(&json, "vk_gamma_2"),
-        delta_g2: json_to_g2(&json, "vk_delta_2"),
-        gamma_abc_g1: json_to_g1_vec(&json, "IC"),
-    }
-}
-
-// Computes the verification key from its JSON serialization
-fn vk_from_json(vk_path: &str) -> VerifyingKey<Curve> {
-    let json = std::fs::read_to_string(vk_path).unwrap();
-    let json: Value = serde_json::from_str(&json).unwrap();
-
-    to_verifying_key(json)
-}
-
-// Computes the verification key from a bytes vector containing its JSON serialization
-fn vk_from_vector(vk: &[u8]) -> VerifyingKey<Curve> {
-    let json = String::from_utf8(vk.to_vec()).expect("Found invalid UTF-8");
-    let json: Value = serde_json::from_str(&json).unwrap();
-
-    to_verifying_key(json)
-}
-
-// Checks verification key to be correct with respect to proving key
-pub fn check_vk_from_zkey(resources_folder: &str, verifying_key: VerifyingKey<Curve>) {
-    let (proving_key, _matrices) = zkey_from_folder(resources_folder).unwrap();
-    assert_eq!(proving_key.vk, verifying_key);
-}

rln/src/circuit/error.rs

@@ -0,0 +1,7 @@
+#[derive(Debug, thiserror::Error)]
+pub enum ZKeyReadError {
+    #[error("No proving key found!")]
+    EmptyBytes,
+    #[error("{0}")]
+    SerializationError(#[from] ark_serialize::SerializationError),
+}

rln/src/circuit/iden3calc.rs

@@ -0,0 +1,94 @@
+// This file 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;
+
+use ruint::aliases::U256;
+use std::collections::HashMap;
+use storage::deserialize_witnesscalc_graph;
+use zeroize::zeroize_flat_type;
+
+use crate::circuit::iden3calc::graph::fr_to_u256;
+use crate::circuit::Fr;
+use crate::utils::FrOrSecret;
+use graph::Node;
+
+pub type InputSignalsInfo = HashMap<String, (usize, usize)>;
+
+pub fn calc_witness<I: IntoIterator<Item = (String, Vec<FrOrSecret>)>>(
+    inputs: I,
+    graph_data: &[u8],
+) -> Vec<Fr> {
+    let mut inputs: HashMap<String, Vec<U256>> = inputs
+        .into_iter()
+        .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();
+
+    let mut inputs_buffer = get_inputs_buffer(get_inputs_size(&nodes));
+    populate_inputs(&inputs, &input_mapping, &mut inputs_buffer);
+    if let Some(v) = inputs.get_mut("identitySecret") {
+        // ~== v[0] = U256::ZERO;
+        unsafe { zeroize_flat_type(v) };
+    }
+    let res = graph::evaluate(&nodes, inputs_buffer.as_slice(), &signals);
+    inputs_buffer.iter_mut().for_each(|i| {
+        unsafe { zeroize_flat_type(i) };
+    });
+    res
+}
+
+fn get_inputs_size(nodes: &[Node]) -> usize {
+    let mut start = false;
+    let mut max_index = 0usize;
+    for &node in nodes.iter() {
+        if let Node::Input(i) = node {
+            if i > max_index {
+                max_index = i;
+            }
+            start = true
+        } else if start {
+            break;
+        }
+    }
+    max_index + 1
+}
+
+fn populate_inputs(
+    input_list: &HashMap<String, Vec<U256>>,
+    inputs_info: &InputSignalsInfo,
+    input_buffer: &mut [U256],
+) {
+    for (key, value) in input_list {
+        let (offset, len) = inputs_info[key];
+        if len != value.len() {
+            panic!("Invalid input length for {key}");
+        }
+
+        for (i, v) in value.iter().enumerate() {
+            input_buffer[offset + i] = *v;
+        }
+    }
+}
+
+/// Allocates inputs vec with position 0 set to 1
+fn get_inputs_buffer(size: usize) -> Vec<U256> {
+    let mut inputs = vec![U256::ZERO; size];
+    inputs[0] = U256::from(1);
+    inputs
+}

rln/src/circuit/iden3calc/graph.rs

@@ -0,0 +1,957 @@
+// This file 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 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::{Deref, Shl, Shr},
+};
+
+use crate::circuit::iden3calc::proto;
+use crate::circuit::Fr;
+
+pub const M: U256 =
+    uint!(21888242871839275222246405745257275088548364400416034343698204186575808495617_U256);
+
+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_with_mode(&mut bytes, Compress::Yes)
+        .map_err(serde::ser::Error::custom)?;
+    s.serialize_bytes(&bytes)
+}
+
+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_with_mode(s.as_slice(), Compress::Yes, Validate::Yes);
+    a.map_err(serde::de::Error::custom)
+}
+
+#[inline(always)]
+pub 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")
+}
+
+#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
+pub enum Operation {
+    Mul,
+    Div,
+    Add,
+    Sub,
+    Pow,
+    Idiv,
+    Mod,
+    Eq,
+    Neq,
+    Lt,
+    Gt,
+    Leq,
+    Geq,
+    Land,
+    Lor,
+    Shl,
+    Shr,
+    Bor,
+    Band,
+    Bxor,
+}
+
+impl Operation {
+    // TODO: rewrite to &U256 type
+    pub fn eval(&self, a: U256, b: U256) -> U256 {
+        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,
+            // 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()
+                } else {
+                    a / b
+                }
+            }
+            Add => a + b,
+            Sub => a - b,
+            Idiv => {
+                if b.is_zero() {
+                    Fr::zero()
+                } else {
+                    let a_u256 = fr_to_u256(&a);
+                    let b_u256 = fr_to_u256(&b);
+                    u256_to_fr(&(a_u256 / b_u256))
+                }
+            }
+            Mod => {
+                if b.is_zero() {
+                    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) {
+                Ordering::Equal => Fr::one(),
+                _ => Fr::zero(),
+            },
+            Neq => 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() {
+                    Fr::zero()
+                } else {
+                    Fr::one()
+                }
+            }
+            Lor => {
+                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),
+        }
+    }
+}
+
+impl From<&Operation> for proto::DuoOp {
+    fn from(v: &Operation) -> Self {
+        match v {
+            Operation::Mul => proto::DuoOp::Mul,
+            Operation::Div => proto::DuoOp::Div,
+            Operation::Add => proto::DuoOp::Add,
+            Operation::Sub => proto::DuoOp::Sub,
+            Operation::Pow => proto::DuoOp::Pow,
+            Operation::Idiv => proto::DuoOp::Idiv,
+            Operation::Mod => proto::DuoOp::Mod,
+            Operation::Eq => proto::DuoOp::Eq,
+            Operation::Neq => proto::DuoOp::Neq,
+            Operation::Lt => proto::DuoOp::Lt,
+            Operation::Gt => proto::DuoOp::Gt,
+            Operation::Leq => proto::DuoOp::Leq,
+            Operation::Geq => proto::DuoOp::Geq,
+            Operation::Land => proto::DuoOp::Land,
+            Operation::Lor => proto::DuoOp::Lor,
+            Operation::Shl => proto::DuoOp::Shl,
+            Operation::Shr => proto::DuoOp::Shr,
+            Operation::Bor => proto::DuoOp::Bor,
+            Operation::Band => proto::DuoOp::Band,
+            Operation::Bxor => proto::DuoOp::Bxor,
+        }
+    }
+}
+
+#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
+pub 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 {
+        match self {
+            UnoOperation::Neg => {
+                if a.is_zero() {
+                    Fr::zero()
+                } else {
+                    let mut x = Fr::MODULUS;
+                    x.sub_with_borrow(&a.into_bigint());
+                    Fr::from_bigint(x).unwrap()
+                }
+            }
+            _ => unimplemented!("uno operator {:?} not implemented for Montgomery", self),
+        }
+    }
+}
+
+impl From<&UnoOperation> for proto::UnoOp {
+    fn from(v: &UnoOperation) -> Self {
+        match v {
+            UnoOperation::Neg => proto::UnoOp::Neg,
+            UnoOperation::Id => proto::UnoOp::Id,
+        }
+    }
+}
+
+#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
+pub 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 {
+        match self {
+            TresOperation::TernCond => {
+                if a.is_zero() {
+                    c
+                } else {
+                    b
+                }
+            }
+        }
+    }
+}
+
+impl From<&TresOperation> for proto::TresOp {
+    fn from(v: &TresOperation) -> Self {
+        match v {
+            TresOperation::TernCond => proto::TresOp::TernCond,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+pub enum Node {
+    Input(usize),
+    Constant(U256),
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
+    MontConstant(Fr),
+    UnoOp(UnoOperation, usize),
+    Op(Operation, usize, usize),
+    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);
+
+    // 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::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]),
+        };
+        values.push(value);
+    }
+
+    // Convert from Montgomery form and return the outputs.
+    let mut out = vec![Fr::from(0); outputs.len()];
+    for i in 0..outputs.len() {
+        out[i] = values[outputs[i]];
+    }
+
+    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 {
+    if b.is_zero() {
+        return a;
+    }
+
+    if b.cmp(&Fr::from(Fr::MODULUS_BIT_SIZE)).is_ge() {
+        return Fr::zero();
+    }
+
+    let n = b.into_bigint().0[0] as u32;
+    let a = a.into_bigint();
+    Fr::from_bigint(a << n).unwrap()
+}
+
+fn shr(a: Fr, b: Fr) -> Fr {
+    if b.is_zero() {
+        return a;
+    }
+
+    match b.cmp(&Fr::from(254u64)) {
+        Ordering::Equal => return Fr::zero(),
+        Ordering::Greater => return Fr::zero(),
+        _ => (),
+    };
+
+    let mut n = b.into_bigint().to_bytes_le()[0];
+    let mut result = a.into_bigint();
+    let c = result.as_mut();
+    while n >= 64 {
+        for i in 0..3 {
+            c[i as usize] = c[(i + 1) as usize];
+        }
+        c[3] = 0;
+        n -= 64;
+    }
+
+    if n == 0 {
+        return Fr::from_bigint(result).unwrap();
+    }
+
+    let mask: u64 = (1 << n) - 1;
+    let mut carrier: u64 = c[3] & mask;
+    c[3] >>= n;
+    for i in (0..3).rev() {
+        let new_carrier = c[i] & mask;
+        c[i] = (c[i] >> n) | (carrier << (64 - n));
+        carrier = new_carrier;
+    }
+    Fr::from_bigint(result).unwrap()
+}
+
+fn bit_and(a: Fr, b: Fr) -> Fr {
+    let a = a.into_bigint();
+    let b = b.into_bigint();
+    let c: [u64; 4] = [
+        a.0[0] & b.0[0],
+        a.0[1] & b.0[1],
+        a.0[2] & b.0[2],
+        a.0[3] & b.0[3],
+    ];
+    let mut d: BigInt<4> = BigInt::new(c);
+    if d > Fr::MODULUS {
+        d.sub_with_borrow(&Fr::MODULUS);
+    }
+
+    Fr::from_bigint(d).unwrap()
+}
+
+fn bit_or(a: Fr, b: Fr) -> Fr {
+    let a = a.into_bigint();
+    let b = b.into_bigint();
+    let c: [u64; 4] = [
+        a.0[0] | b.0[0],
+        a.0[1] | b.0[1],
+        a.0[2] | b.0[2],
+        a.0[3] | b.0[3],
+    ];
+    let mut d: BigInt<4> = BigInt::new(c);
+    if d > Fr::MODULUS {
+        d.sub_with_borrow(&Fr::MODULUS);
+    }
+
+    Fr::from_bigint(d).unwrap()
+}
+
+fn bit_xor(a: Fr, b: Fr) -> Fr {
+    let a = a.into_bigint();
+    let b = b.into_bigint();
+    let c: [u64; 4] = [
+        a.0[0] ^ b.0[0],
+        a.0[1] ^ b.0[1],
+        a.0[2] ^ b.0[2],
+        a.0[3] ^ b.0[3],
+    ];
+    let mut d: BigInt<4> = BigInt::new(c);
+    if d > Fr::MODULUS {
+        d.sub_with_borrow(&Fr::MODULUS);
+    }
+
+    Fr::from_bigint(d).unwrap()
+}
+
+// M / 2
+const HALF_M: U256 =
+    uint!(10944121435919637611123202872628637544274182200208017171849102093287904247808_U256);
+
+fn u_gte(a: &U256, b: &U256) -> U256 {
+    let a_neg = &HALF_M < a;
+    let b_neg = &HALF_M < b;
+
+    match (a_neg, b_neg) {
+        (false, false) => U256::from(a >= b),
+        (true, false) => uint!(0_U256),
+        (false, true) => uint!(1_U256),
+        (true, true) => U256::from(a >= b),
+    }
+}
+
+fn u_lte(a: &U256, b: &U256) -> U256 {
+    let a_neg = &HALF_M < a;
+    let b_neg = &HALF_M < b;
+
+    match (a_neg, b_neg) {
+        (false, false) => U256::from(a <= b),
+        (true, false) => uint!(1_U256),
+        (false, true) => uint!(0_U256),
+        (true, true) => U256::from(a <= b),
+    }
+}
+
+fn u_gt(a: &U256, b: &U256) -> U256 {
+    let a_neg = &HALF_M < a;
+    let b_neg = &HALF_M < b;
+
+    match (a_neg, b_neg) {
+        (false, false) => U256::from(a > b),
+        (true, false) => uint!(0_U256),
+        (false, true) => uint!(1_U256),
+        (true, true) => U256::from(a > b),
+    }
+}
+
+fn u_lt(a: &U256, b: &U256) -> U256 {
+    let a_neg = &HALF_M < a;
+    let b_neg = &HALF_M < b;
+
+    match (a_neg, b_neg) {
+        (false, false) => U256::from(a < b),
+        (true, false) => uint!(1_U256),
+        (false, true) => uint!(0_U256),
+        (true, true) => U256::from(a < b),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ruint::uint;
+    use std::ops::Div;
+    use std::str::FromStr;
+
+    #[test]
+    fn test_ok() {
+        let a = Fr::from(4u64);
+        let b = Fr::from(2u64);
+        let c = shl(a, b);
+        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)),
+            Fr::from_str(
+                "7296080957279758407415468581752425029516121466805344781232734728858602831873"
+            )
+            .unwrap()
+        );
+
+        assert_eq!(
+            Operation::Div.eval_fr(Fr::from(6u64), Fr::from(2u64)),
+            Fr::from_str("3").unwrap()
+        );
+
+        assert_eq!(
+            Operation::Div.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Fr::from_str(
+                "10944121435919637611123202872628637544274182200208017171849102093287904247812"
+            )
+            .unwrap()
+        );
+    }
+
+    #[test]
+    fn test_idiv() {
+        assert_eq!(
+            Operation::Idiv.eval_fr(Fr::from(2u64), Fr::from(3u64)),
+            Fr::from_str("0").unwrap()
+        );
+
+        assert_eq!(
+            Operation::Idiv.eval_fr(Fr::from(6u64), Fr::from(2u64)),
+            Fr::from_str("3").unwrap()
+        );
+
+        assert_eq!(
+            Operation::Idiv.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Fr::from_str("3").unwrap()
+        );
+    }
+
+    #[test]
+    fn test_fr_mod() {
+        assert_eq!(
+            Operation::Mod.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Fr::from_str("1").unwrap()
+        );
+
+        assert_eq!(
+            Operation::Mod.eval_fr(Fr::from(7u64), Fr::from(9u64)),
+            Fr::from_str("7").unwrap()
+        );
+    }
+
+    #[test]
+    fn test_u_gte() {
+        let result = u_gte(&uint!(10_U256), &uint!(3_U256));
+        assert_eq!(result, uint!(1_U256));
+
+        let result = u_gte(&uint!(3_U256), &uint!(3_U256));
+        assert_eq!(result, uint!(1_U256));
+
+        let result = u_gte(&uint!(2_U256), &uint!(3_U256));
+        assert_eq!(result, uint!(0_U256));
+
+        // -1 >= 3 => 0
+        let result = u_gte(
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495616_U256
+            ),
+            &uint!(3_U256),
+        );
+        assert_eq!(result, uint!(0_U256));
+
+        // -1 >= -2 => 1
+        let result = u_gte(
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495616_U256
+            ),
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495615_U256
+            ),
+        );
+        assert_eq!(result, uint!(1_U256));
+
+        // -2 >= -1 => 0
+        let result = u_gte(
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495615_U256
+            ),
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495616_U256
+            ),
+        );
+        assert_eq!(result, uint!(0_U256));
+
+        // -2 == -2 => 1
+        let result = u_gte(
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495615_U256
+            ),
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495615_U256
+            ),
+        );
+        assert_eq!(result, uint!(1_U256));
+    }
+
+    #[test]
+    fn test_x() {
+        let x = M.div(uint!(2_U256));
+
+        println!("x: {:?}", x.as_limbs());
+        println!("x: {M}");
+    }
+
+    #[test]
+    fn test_2() {
+        let nodes: Vec<Node> = vec![];
+        // let node = nodes[0];
+        let node = nodes.first();
+        println!("{node:?}");
+    }
+}

rln/src/circuit/iden3calc/proto.rs

@@ -0,0 +1,117 @@
+// This file 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 {
+    #[prost(bytes = "vec", tag = "1")]
+    pub value_le: Vec<u8>,
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub struct InputNode {
+    #[prost(uint32, tag = "1")]
+    pub idx: u32,
+}
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct ConstantNode {
+    #[prost(message, optional, tag = "1")]
+    pub value: Option<BigUInt>,
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub 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 {
+    #[prost(enumeration = "DuoOp", tag = "1")]
+    pub op: i32,
+    #[prost(uint32, tag = "2")]
+    pub a_idx: u32,
+    #[prost(uint32, tag = "3")]
+    pub b_idx: u32,
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub struct TresOpNode {
+    #[prost(enumeration = "TresOp", tag = "1")]
+    pub op: i32,
+    #[prost(uint32, tag = "2")]
+    pub a_idx: u32,
+    #[prost(uint32, tag = "3")]
+    pub b_idx: u32,
+    #[prost(uint32, tag = "4")]
+    pub c_idx: u32,
+}
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub 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 {
+        #[prost(message, tag = "1")]
+        Input(super::InputNode),
+        #[prost(message, tag = "2")]
+        Constant(super::ConstantNode),
+        #[prost(message, tag = "3")]
+        UnoOp(super::UnoOpNode),
+        #[prost(message, tag = "4")]
+        DuoOp(super::DuoOpNode),
+        #[prost(message, tag = "5")]
+        TresOp(super::TresOpNode),
+    }
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub struct SignalDescription {
+    #[prost(uint32, tag = "1")]
+    pub offset: u32,
+    #[prost(uint32, tag = "2")]
+    pub len: u32,
+}
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub 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 {
+    Mul = 0,
+    Div = 1,
+    Add = 2,
+    Sub = 3,
+    Pow = 4,
+    Idiv = 5,
+    Mod = 6,
+    Eq = 7,
+    Neq = 8,
+    Lt = 9,
+    Gt = 10,
+    Leq = 11,
+    Geq = 12,
+    Land = 13,
+    Lor = 14,
+    Shl = 15,
+    Shr = 16,
+    Bor = 17,
+    Band = 18,
+    Bxor = 19,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, ::prost::Enumeration)]
+pub enum UnoOp {
+    Neg = 0,
+    Id = 1,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, ::prost::Enumeration)]
+pub enum TresOp {
+    TernCond = 0,
+}

rln/src/circuit/iden3calc/storage.rs

@@ -0,0 +1,497 @@
+// This file 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 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},
+    proto, InputSignalsInfo,
+};
+
+// 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),
+            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()))
+            }
+            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)
+            }
+            proto::node::Node::DuoOp(duo_op_node) => {
+                let op = proto::DuoOp::try_from(duo_op_node.op).unwrap();
+                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(
+                    op.into(),
+                    tres_op_node.a_idx as usize,
+                    tres_op_node.b_idx as usize,
+                    tres_op_node.c_idx as usize,
+                )
+            }
+        }
+    }
+}
+
+impl From<&graph::Node> for proto::node::Node {
+    fn from(node: &graph::Node) -> Self {
+        match node {
+            graph::Node::Input(i) => proto::node::Node::Input(proto::InputNode { idx: *i as u32 }),
+            graph::Node::Constant(_) => {
+                panic!("We are not supposed to write Constant to the witnesscalc graph. All Constant should be converted to MontConstant.");
+            }
+            graph::Node::UnoOp(op, a) => {
+                let op = proto::UnoOp::from(op);
+                proto::node::Node::UnoOp(proto::UnoOpNode {
+                    op: op as i32,
+                    a_idx: *a as u32,
+                })
+            }
+            graph::Node::Op(op, a, b) => proto::node::Node::DuoOp(proto::DuoOpNode {
+                op: proto::DuoOp::from(op) as i32,
+                a_idx: *a as u32,
+                b_idx: *b as u32,
+            }),
+            graph::Node::TresOp(op, a, b, c) => proto::node::Node::TresOp(proto::TresOpNode {
+                op: proto::TresOp::from(op) as i32,
+                a_idx: *a as u32,
+                b_idx: *b as u32,
+                c_idx: *c as u32,
+            }),
+            graph::Node::MontConstant(c) => {
+                let bi = Into::<num_bigint::BigUint>::into(*c);
+                let i = proto::BigUInt {
+                    value_le: bi.to_bytes_le(),
+                };
+                proto::node::Node::Constant(proto::ConstantNode { value: Some(i) })
+            }
+        }
+    }
+}
+
+impl From<proto::UnoOp> for UnoOperation {
+    fn from(value: proto::UnoOp) -> Self {
+        match value {
+            proto::UnoOp::Neg => UnoOperation::Neg,
+            proto::UnoOp::Id => UnoOperation::Id,
+        }
+    }
+}
+
+impl From<proto::DuoOp> for Operation {
+    fn from(value: proto::DuoOp) -> Self {
+        match value {
+            proto::DuoOp::Mul => Operation::Mul,
+            proto::DuoOp::Div => Operation::Div,
+            proto::DuoOp::Add => Operation::Add,
+            proto::DuoOp::Sub => Operation::Sub,
+            proto::DuoOp::Pow => Operation::Pow,
+            proto::DuoOp::Idiv => Operation::Idiv,
+            proto::DuoOp::Mod => Operation::Mod,
+            proto::DuoOp::Eq => Operation::Eq,
+            proto::DuoOp::Neq => Operation::Neq,
+            proto::DuoOp::Lt => Operation::Lt,
+            proto::DuoOp::Gt => Operation::Gt,
+            proto::DuoOp::Leq => Operation::Leq,
+            proto::DuoOp::Geq => Operation::Geq,
+            proto::DuoOp::Land => Operation::Land,
+            proto::DuoOp::Lor => Operation::Lor,
+            proto::DuoOp::Shl => Operation::Shl,
+            proto::DuoOp::Shr => Operation::Shr,
+            proto::DuoOp::Bor => Operation::Bor,
+            proto::DuoOp::Band => Operation::Band,
+            proto::DuoOp::Bxor => Operation::Bxor,
+        }
+    }
+}
+
+impl From<proto::TresOp> for graph::TresOperation {
+    fn from(value: proto::TresOp) -> Self {
+        match value {
+            proto::TresOp::TernCond => TresOperation::TernCond,
+        }
+    }
+}
+
+pub 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();
+    ptr += WITNESSCALC_GRAPH_MAGIC.len();
+
+    w.write_u64::<LittleEndian>(nodes.len() as u64)?;
+    ptr += 8;
+
+    let metadata = proto::GraphMetadata {
+        witness_signals: witness_signals
+            .iter()
+            .map(|x| *x as u32)
+            .collect::<Vec<u32>>(),
+        inputs: input_signals
+            .iter()
+            .map(|(k, v)| {
+                let sig = proto::SignalDescription {
+                    offset: v.0 as u32,
+                    len: v.1 as u32,
+                };
+                (k.clone(), sig)
+            })
+            .collect(),
+    };
+
+    // capacity of buf should be enough to hold the largest message + 10 bytes
+    // of varint length
+    let mut buf = Vec::with_capacity(metadata.encoded_len() + MAX_VARINT_LENGTH);
+
+    for node in nodes {
+        let node_pb = proto::Node {
+            node: Some(proto::node::Node::from(node)),
+        };
+
+        assert_eq!(buf.len(), 0);
+        node_pb.encode_length_delimited(&mut buf)?;
+        ptr += buf.len();
+
+        w.write_all(&buf)?;
+        buf.clear();
+    }
+
+    metadata.encode_length_delimited(&mut buf)?;
+    w.write_all(&buf)?;
+    buf.clear();
+
+    w.write_u64::<LittleEndian>(ptr as u64)?;
+
+    Ok(())
+}
+
+fn read_message_length<R: Read>(rw: &mut WriteBackReader<R>) -> std::io::Result<usize> {
+    let mut buf = [0u8; MAX_VARINT_LENGTH];
+    let bytes_read = rw.read(&mut buf)?;
+    if bytes_read == 0 {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::UnexpectedEof,
+            "Unexpected EOF",
+        ));
+    }
+
+    let len_delimiter = prost::decode_length_delimiter(buf.as_ref())?;
+
+    let lnln = prost::length_delimiter_len(len_delimiter);
+
+    if lnln < bytes_read {
+        rw.write_all(&buf[lnln..bytes_read])?;
+    }
+
+    Ok(len_delimiter)
+}
+
+fn read_message<R: Read, M: Message + std::default::Default>(
+    rw: &mut WriteBackReader<R>,
+) -> std::io::Result<M> {
+    let ln = read_message_length(rw)?;
+    let mut buf = vec![0u8; ln];
+    let bytes_read = rw.read(&mut buf)?;
+    if bytes_read != ln {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::UnexpectedEof,
+            "Unexpected EOF",
+        ));
+    }
+
+    let msg = prost::Message::decode(&buf[..])?;
+
+    Ok(msg)
+}
+
+pub fn deserialize_witnesscalc_graph(
+    r: impl Read,
+) -> std::io::Result<(Vec<graph::Node>, Vec<usize>, InputSignalsInfo)> {
+    let mut br = WriteBackReader::new(r);
+    let mut magic = [0u8; WITNESSCALC_GRAPH_MAGIC.len()];
+
+    br.read_exact(&mut magic)?;
+
+    if !magic.eq(WITNESSCALC_GRAPH_MAGIC) {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            "Invalid magic",
+        ));
+    }
+
+    let nodes_num = br.read_u64::<LittleEndian>()?;
+    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);
+    }
+
+    let md: proto::GraphMetadata = read_message(&mut br)?;
+
+    let witness_signals = md
+        .witness_signals
+        .iter()
+        .map(|x| *x as usize)
+        .collect::<Vec<usize>>();
+
+    let input_signals = md
+        .inputs
+        .iter()
+        .map(|(k, v)| (k.clone(), (v.offset as usize, v.len as usize)))
+        .collect::<InputSignalsInfo>();
+
+    Ok((nodes, witness_signals, input_signals))
+}
+
+struct WriteBackReader<R: Read> {
+    reader: R,
+    buffer: Vec<u8>,
+}
+
+impl<R: Read> WriteBackReader<R> {
+    fn new(reader: R) -> Self {
+        WriteBackReader {
+            reader,
+            buffer: Vec::new(),
+        }
+    }
+}
+
+impl<R: Read> Read for WriteBackReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+        if buf.is_empty() {
+            return Ok(0);
+        }
+
+        let mut n = 0usize;
+
+        if !self.buffer.is_empty() {
+            n = std::cmp::min(buf.len(), self.buffer.len());
+            self.buffer[self.buffer.len() - n..]
+                .iter()
+                .rev()
+                .enumerate()
+                .for_each(|(i, x)| {
+                    buf[i] = *x;
+                });
+            self.buffer.truncate(self.buffer.len() - n);
+        }
+
+        while n < buf.len() {
+            let m = self.reader.read(&mut buf[n..])?;
+            if m == 0 {
+                break;
+            }
+            n += m;
+        }
+
+        Ok(n)
+    }
+}
+
+impl<R: Read> Write for WriteBackReader<R> {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        self.buffer.reserve(buf.len());
+        self.buffer.extend(buf.iter().rev());
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use byteorder::ByteOrder;
+    use core::str::FromStr;
+    use graph::{Operation, TresOperation, UnoOperation};
+    use std::collections::HashMap;
+
+    #[test]
+    fn test_read_message() {
+        let mut buf = Vec::new();
+        let n1 = proto::Node {
+            node: Some(proto::node::Node::Input(proto::InputNode { idx: 1 })),
+        };
+        n1.encode_length_delimited(&mut buf).unwrap();
+
+        let n2 = proto::Node {
+            node: Some(proto::node::Node::Input(proto::InputNode { idx: 2 })),
+        };
+        n2.encode_length_delimited(&mut buf).unwrap();
+
+        let mut reader = std::io::Cursor::new(&buf);
+
+        let mut rw = WriteBackReader::new(&mut reader);
+
+        let got_n1: proto::Node = read_message(&mut rw).unwrap();
+        assert!(n1.eq(&got_n1));
+
+        let got_n2: proto::Node = read_message(&mut rw).unwrap();
+        assert!(n2.eq(&got_n2));
+
+        assert_eq!(reader.position(), buf.len() as u64);
+    }
+
+    #[test]
+    fn test_read_message_variant() {
+        let nodes = vec![
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::Input(0))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::MontConstant(
+                    Fr::from_str("1").unwrap(),
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::UnoOp(
+                    UnoOperation::Id,
+                    4,
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::Op(
+                    Operation::Mul,
+                    5,
+                    6,
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::TresOp(
+                    TresOperation::TernCond,
+                    7,
+                    8,
+                    9,
+                ))),
+            },
+        ];
+
+        let mut buf = Vec::new();
+        for n in &nodes {
+            n.encode_length_delimited(&mut buf).unwrap();
+        }
+
+        let mut nodes_got: Vec<proto::Node> = Vec::new();
+        let mut reader = std::io::Cursor::new(&buf);
+        let mut rw = WriteBackReader::new(&mut reader);
+        for _ in 0..nodes.len() {
+            nodes_got.push(read_message(&mut rw).unwrap());
+        }
+
+        assert_eq!(nodes, nodes_got);
+    }
+
+    #[test]
+    fn test_write_back_reader() {
+        let data = [1u8, 2, 3, 4, 5, 6];
+        let mut r = WriteBackReader::new(std::io::Cursor::new(&data));
+
+        let buf = &mut [0u8; 5];
+        r.read_exact(buf).unwrap();
+        assert_eq!(buf, &[1, 2, 3, 4, 5]);
+
+        // return [4, 5] to reader
+        r.write_all(&buf[3..]).unwrap();
+        // return [2, 3] to reader
+        r.write_all(&buf[1..3]).unwrap();
+
+        buf.fill(0);
+
+        // read 3 bytes, expect [2, 3, 4] after returns
+        let mut n = r.read(&mut buf[..3]).unwrap();
+        assert_eq!(n, 3);
+        assert_eq!(buf, &[2, 3, 4, 0, 0]);
+
+        buf.fill(0);
+
+        // read everything left in reader
+        n = r.read(buf).unwrap();
+        assert_eq!(n, 2);
+        assert_eq!(buf, &[5, 6, 0, 0, 0]);
+    }
+
+    #[test]
+    fn test_deserialize_inputs() {
+        let nodes = vec![
+            graph::Node::Input(0),
+            graph::Node::MontConstant(Fr::from_str("1").unwrap()),
+            graph::Node::UnoOp(UnoOperation::Id, 4),
+            graph::Node::Op(Operation::Mul, 5, 6),
+            graph::Node::TresOp(TresOperation::TernCond, 7, 8, 9),
+        ];
+
+        let witness_signals = vec![4, 1];
+
+        let mut input_signals: InputSignalsInfo = HashMap::new();
+        input_signals.insert("sig1".to_string(), (1, 3));
+        input_signals.insert("sig2".to_string(), (5, 1));
+
+        let mut tmp = Vec::new();
+        serialize_witnesscalc_graph(&mut tmp, &nodes, &witness_signals, &input_signals).unwrap();
+
+        let mut reader = std::io::Cursor::new(&tmp);
+
+        let (nodes_res, witness_signals_res, input_signals_res) =
+            deserialize_witnesscalc_graph(&mut reader).unwrap();
+
+        assert_eq!(nodes, nodes_res);
+        assert_eq!(input_signals, input_signals_res);
+        assert_eq!(witness_signals, witness_signals_res);
+
+        let metadata_start = LittleEndian::read_u64(&tmp[tmp.len() - 8..]);
+
+        let mt_reader = std::io::Cursor::new(&tmp[metadata_start as usize..]);
+        let mut rw = WriteBackReader::new(mt_reader);
+        let metadata: proto::GraphMetadata = read_message(&mut rw).unwrap();
+
+        let metadata_want = proto::GraphMetadata {
+            witness_signals: vec![4, 1],
+            inputs: input_signals
+                .iter()
+                .map(|(k, v)| {
+                    (
+                        k.clone(),
+                        proto::SignalDescription {
+                            offset: v.0 as u32,
+                            len: v.1 as u32,
+                        },
+                    )
+                })
+                .collect(),
+        };
+
+        assert_eq!(metadata, metadata_want);
+    }
+}

rln/src/circuit/mod.rs

@@ -0,0 +1,132 @@
+// This crate provides interfaces for the zero-knowledge circuit and keys
+
+pub mod error;
+pub mod iden3calc;
+pub mod qap;
+
+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 crate::circuit::error::ZKeyReadError;
+use crate::circuit::iden3calc::calc_witness;
+
+use {ark_ff::Field, ark_serialize::CanonicalDeserialize, ark_serialize::CanonicalSerialize};
+
+use crate::utils::FrOrSecret;
+
+pub const ARKZKEY_BYTES: &[u8] = include_bytes!("../../resources/tree_depth_30/rln_final.arkzkey");
+
+#[cfg(not(target_arch = "wasm32"))]
+const GRAPH_BYTES: &[u8] = include_bytes!("../../resources/tree_depth_30/graph.bin");
+
+lazy_static! {
+    static ref ARKZKEY: (ProvingKey<Curve>, ConstraintMatrices<Fr>) =
+        read_arkzkey_from_bytes_uncompressed(ARKZKEY_BYTES).expect("Failed to read arkzkey");
+}
+
+pub const TEST_TREE_DEPTH: usize = 30;
+
+// 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
+pub type Curve = Bn254;
+pub type Fr = ArkFr;
+pub type Fq = ArkFq;
+pub type Fq2 = ArkFq2;
+pub type G1Affine = ArkG1Affine;
+pub type G1Projective = ArkG1Projective;
+pub type G2Affine = ArkG2Affine;
+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>), ZKeyReadError> {
+    if zkey_data.is_empty() {
+        return Err(ZKeyReadError::EmptyBytes);
+    }
+
+    let proving_key_and_matrices = read_arkzkey_from_bytes_uncompressed(zkey_data)?;
+
+    Ok(proving_key_and_matrices)
+}
+
+// Loads the proving key
+#[cfg(not(target_arch = "wasm32"))]
+pub fn zkey_from_folder() -> &'static (ProvingKey<Curve>, ConstraintMatrices<Fr>) {
+    &ARKZKEY
+}
+
+pub fn calculate_rln_witness<I: IntoIterator<Item = (String, Vec<FrOrSecret>)>>(
+    inputs: I,
+    graph_data: &[u8],
+) -> Vec<Fr> {
+    calc_witness(inputs, graph_data)
+}
+
+#[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
+////////////////////////////////////////////////////////
+
+#[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
+pub struct SerializableProvingKey(pub ProvingKey<Bn254>);
+
+#[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>,
+}
+
+#[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
+pub struct SerializableMatrix<F: Field> {
+    pub data: Vec<Vec<(F, usize)>>,
+}
+
+pub fn read_arkzkey_from_bytes_uncompressed(
+    arkzkey_data: &[u8],
+) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>), ZKeyReadError> {
+    if arkzkey_data.is_empty() {
+        return Err(ZKeyReadError::EmptyBytes);
+    }
+
+    let mut cursor = std::io::Cursor::new(arkzkey_data);
+
+    let serialized_proving_key =
+        SerializableProvingKey::deserialize_uncompressed_unchecked(&mut cursor)?;
+
+    let serialized_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 {
+        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,
+        a_num_non_zero: serialized_constraint_matrices.a_num_non_zero,
+        b_num_non_zero: serialized_constraint_matrices.b_num_non_zero,
+        c_num_non_zero: serialized_constraint_matrices.c_num_non_zero,
+        a: serialized_constraint_matrices.a.data,
+        b: serialized_constraint_matrices.b.data,
+        c: serialized_constraint_matrices.c.data,
+    };
+
+    Ok((proving_key, constraint_matrices))
+}

rln/src/circuit/qap.rs

@@ -0,0 +1,120 @@
+// 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/circom/qap.rs
+
+use ark_ff::PrimeField;
+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;
+
+impl R1CSToQAP for CircomReduction {
+    #[allow(clippy::type_complexity)]
+    fn instance_map_with_evaluation<F: PrimeField, D: EvaluationDomain<F>>(
+        cs: ConstraintSystemRef<F>,
+        t: &F,
+    ) -> Result<(Vec<F>, Vec<F>, Vec<F>, F, usize, usize), SynthesisError> {
+        LibsnarkReduction::instance_map_with_evaluation::<F, D>(cs, t)
+    }
+
+    fn witness_map_from_matrices<F: PrimeField, D: EvaluationDomain<F>>(
+        matrices: &ConstraintMatrices<F>,
+        num_inputs: usize,
+        num_constraints: usize,
+        full_assignment: &[F],
+    ) -> Result<Vec<F>, SynthesisError> {
+        let zero = F::zero();
+        let domain =
+            D::new(num_constraints + num_inputs).ok_or(SynthesisError::PolynomialDegreeTooLarge)?;
+        let domain_size = domain.size();
+
+        let mut a = vec![zero; domain_size];
+        let mut b = vec![zero; domain_size];
+
+        #[allow(unexpected_cfgs)]
+        cfg_iter_mut!(a[..num_constraints])
+            .zip(cfg_iter_mut!(b[..num_constraints]))
+            .zip(cfg_iter!(&matrices.a))
+            .zip(cfg_iter!(&matrices.b))
+            .for_each(|(((a, b), at_i), bt_i)| {
+                *a = evaluate_constraint(at_i, full_assignment);
+                *b = evaluate_constraint(bt_i, full_assignment);
+            });
+
+        {
+            let start = num_constraints;
+            let end = start + num_inputs;
+            a[start..end].clone_from_slice(&full_assignment[..num_inputs]);
+        }
+
+        let mut c = vec![zero; domain_size];
+        #[allow(unexpected_cfgs)]
+        cfg_iter_mut!(c[..num_constraints])
+            .zip(&a)
+            .zip(&b)
+            .for_each(|((c_i, &a), &b)| {
+                *c_i = a * b;
+            });
+
+        domain.ifft_in_place(&mut a);
+        domain.ifft_in_place(&mut b);
+
+        let root_of_unity = {
+            let domain_size_double = 2 * domain_size;
+            let domain_double =
+                D::new(domain_size_double).ok_or(SynthesisError::PolynomialDegreeTooLarge)?;
+            domain_double.element(1)
+        };
+        D::distribute_powers_and_mul_by_const(&mut a, root_of_unity, F::one());
+        D::distribute_powers_and_mul_by_const(&mut b, root_of_unity, F::one());
+
+        domain.fft_in_place(&mut a);
+        domain.fft_in_place(&mut b);
+
+        let mut ab = domain.mul_polynomials_in_evaluation_domain(&a, &b);
+        drop(a);
+        drop(b);
+
+        domain.ifft_in_place(&mut c);
+        D::distribute_powers_and_mul_by_const(&mut c, root_of_unity, F::one());
+        domain.fft_in_place(&mut c);
+
+        #[allow(unexpected_cfgs)]
+        cfg_iter_mut!(ab)
+            .zip(c)
+            .for_each(|(ab_i, c_i)| *ab_i -= &c_i);
+
+        Ok(ab)
+    }
+
+    fn h_query_scalars<F: PrimeField, D: EvaluationDomain<F>>(
+        max_power: usize,
+        t: F,
+        _: F,
+        delta_inverse: F,
+    ) -> Result<Vec<F>, SynthesisError> {
+        // the usual H query has domain-1 powers. Z has domain powers. So HZ has 2*domain-1 powers.
+        #[allow(unexpected_cfgs)]
+        let mut scalars = cfg_into_iter!(0..2 * max_power + 1)
+            .map(|i| delta_inverse * t.pow([i as u64]))
+            .collect::<Vec<_>>();
+        let domain_size = scalars.len();
+        let domain = D::new(domain_size).ok_or(SynthesisError::PolynomialDegreeTooLarge)?;
+        // generate the lagrange coefficients
+        domain.ifft_in_place(&mut scalars);
+        #[allow(unexpected_cfgs)]
+        Ok(cfg_into_iter!(scalars).skip(1).step_by(2).collect())
+    }
+}

rln/src/error.rs

@@ -0,0 +1,79 @@
+use crate::circuit::error::ZKeyReadError;
+use ark_bn254::Fr;
+use ark_relations::r1cs::SynthesisError;
+use ark_serialize::SerializationError;
+use num_bigint::{BigInt, ParseBigIntError};
+use std::array::TryFromSliceError;
+use std::num::TryFromIntError;
+use std::string::FromUtf8Error;
+use thiserror::Error;
+use utils::error::{FromConfigError, ZerokitMerkleTreeError};
+
+#[derive(Debug, thiserror::Error)]
+pub enum ConversionError {
+    #[error("Expected radix 10 or 16")]
+    WrongRadix,
+    #[error("{0}")]
+    ParseBigInt(#[from] ParseBigIntError),
+    #[error("{0}")]
+    ToUsize(#[from] TryFromIntError),
+    #[error("{0}")]
+    FromSlice(#[from] TryFromSliceError),
+    #[error("Input data too short: expected at least {expected} bytes, got {actual} bytes")]
+    InsufficientData { expected: usize, actual: usize },
+}
+
+#[derive(Error, Debug)]
+pub enum ProofError {
+    #[error("{0}")]
+    ProtocolError(#[from] ProtocolError),
+    #[error("Error producing proof: {0}")]
+    SynthesisError(#[from] SynthesisError),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ProtocolError {
+    #[error("{0}")]
+    Conversion(#[from] ConversionError),
+    #[error("Expected to read {0} bytes but read only {1} bytes")]
+    InvalidReadLen(usize, usize),
+    #[error("Cannot convert bigint {0:?} to biguint")]
+    BigUintConversion(BigInt),
+    #[error("{0}")]
+    JsonError(#[from] serde_json::Error),
+    #[error("Message id ({0}) is not within user_message_limit ({1})")]
+    InvalidMessageId(Fr, Fr),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ComputeIdSecretError {
+    /// Usually it means that the same signal is used to recover the user secret hash
+    #[error("Cannot recover secret: division by zero")]
+    DivisionByZero,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum RLNError {
+    #[error("I/O error: {0}")]
+    IO(#[from] std::io::Error),
+    #[error("Utf8 error: {0}")]
+    Utf8(#[from] FromUtf8Error),
+    #[error("Serde json error: {0}")]
+    JSON(#[from] serde_json::Error),
+    #[error("Config error: {0}")]
+    Config(#[from] FromConfigError),
+    #[error("Serialization error: {0}")]
+    Serialization(#[from] SerializationError),
+    #[error("Merkle tree error: {0}")]
+    MerkleTree(#[from] ZerokitMerkleTreeError),
+    #[error("ZKey error: {0}")]
+    ZKey(#[from] ZKeyReadError),
+    #[error("Conversion error: {0}")]
+    Conversion(#[from] ConversionError),
+    #[error("Protocol error: {0}")]
+    Protocol(#[from] ProtocolError),
+    #[error("Proof error: {0}")]
+    Proof(#[from] ProofError),
+    #[error("Unable to extract secret")]
+    RecoverSecret(#[from] ComputeIdSecretError),
+}

rln/src/hashers.rs

@@ -0,0 +1,77 @@
+/// This crate instantiates the Poseidon hash algorithm.
+use crate::{
+    circuit::Fr,
+    utils::{bytes_be_to_fr, bytes_le_to_fr},
+};
+use once_cell::sync::Lazy;
+use tiny_keccak::{Hasher, Keccak};
+use utils::poseidon::Poseidon;
+
+/// 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] = [
+    (2, 8, 56, 0),
+    (3, 8, 57, 0),
+    (4, 8, 56, 0),
+    (5, 8, 60, 0),
+    (6, 8, 60, 0),
+    (7, 8, 63, 0),
+    (8, 8, 64, 0),
+    (9, 8, 63, 0),
+];
+
+/// 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")
+}
+
+/// The zerokit RLN Merkle tree Hasher.
+#[derive(Clone, Copy, PartialEq, Eq)]
+pub struct PoseidonHash;
+
+/// The default Hasher trait used by Merkle tree implementation in utils.
+impl utils::merkle_tree::Hasher for PoseidonHash {
+    type Fr = Fr;
+
+    fn default_leaf() -> Self::Fr {
+        Self::Fr::from(0)
+    }
+
+    fn hash(inputs: &[Self::Fr]) -> Self::Fr {
+        poseidon_hash(inputs)
+    }
+}
+
+/// Hashes arbitrary signal to the underlying prime field.
+pub fn hash_to_field_le(signal: &[u8]) -> Fr {
+    // We hash the input signal using Keccak256
+    let mut hash = [0; 32];
+    let mut hasher = Keccak::v256();
+    hasher.update(signal);
+    hasher.finalize(&mut hash);
+
+    // We export the hash as a field element
+    let (el, _) = bytes_le_to_fr(hash.as_ref());
+    el
+}
+
+/// Hashes arbitrary signal to the underlying prime field.
+pub fn hash_to_field_be(signal: &[u8]) -> Fr {
+    // 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());
+    el
+}

rln/src/lib.rs

@@ -1,432 +1,35 @@
-#![allow(dead_code)]
-
 pub mod circuit;
+pub mod error;
+#[cfg(not(target_arch = "wasm32"))]
 pub mod ffi;
-pub mod merkle_tree;
-pub mod poseidon_constants;
-pub mod poseidon_hash;
+pub mod hashers;
+#[cfg(feature = "pmtree-ft")]
+pub mod pm_tree_adapter;
+#[cfg(not(feature = "stateless"))]
 pub mod poseidon_tree;
 pub mod protocol;
 pub mod public;
+#[cfg(test)]
+pub mod public_api_tests;
 pub mod utils;
 
-#[cfg(test)]
-mod test {
+// 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."
+);
 
-    use crate::circuit::{
-        circom_from_folder, vk_from_folder, zkey_from_folder, Fr, TEST_RESOURCES_FOLDER,
-        TEST_TREE_HEIGHT,
-    };
-    use crate::poseidon_hash::poseidon_hash;
-    use crate::poseidon_tree::PoseidonTree;
-    use crate::protocol::*;
-    use crate::utils::str_to_fr;
-
-    // Input generated with https://github.com/oskarth/zk-kit/commit/b6a872f7160c7c14e10a0ea40acab99cbb23c9a8
-    const WITNESS_JSON_15: &str = r#"
-            {
-              "identity_secret": "12825549237505733615964533204745049909430608936689388901883576945030025938736",
-              "path_elements": [
-                "18622655742232062119094611065896226799484910997537830749762961454045300666333",
-                "20590447254980891299813706518821659736846425329007960381537122689749540452732",
-                "7423237065226347324353380772367382631490014989348495481811164164159255474657",
-                "11286972368698509976183087595462810875513684078608517520839298933882497716792",
-                "3607627140608796879659380071776844901612302623152076817094415224584923813162",
-                "19712377064642672829441595136074946683621277828620209496774504837737984048981",
-                "20775607673010627194014556968476266066927294572720319469184847051418138353016",
-                "3396914609616007258851405644437304192397291162432396347162513310381425243293",
-                "21551820661461729022865262380882070649935529853313286572328683688269863701601",
-                "6573136701248752079028194407151022595060682063033565181951145966236778420039",
-                "12413880268183407374852357075976609371175688755676981206018884971008854919922",
-                "14271763308400718165336499097156975241954733520325982997864342600795471836726",
-                "20066985985293572387227381049700832219069292839614107140851619262827735677018",
-                "9394776414966240069580838672673694685292165040808226440647796406499139370960",
-                "11331146992410411304059858900317123658895005918277453009197229807340014528524"
-              ],
-              "identity_path_index": [
-                1,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0
-              ],
-              "x": "8143228284048792769012135629627737459844825626241842423967352803501040982",
-              "epoch": "0x0000005b612540fc986b42322f8cb91c2273afad58ed006fdba0c97b4b16b12f",
-              "rln_identifier": "11412926387081627876309792396682864042420635853496105400039841573530884328439"
-            }
-        "#;
-
-    // Input generated with protocol::random_rln_witness
-    const WITNESS_JSON_19: &str = r#"
-            {
-              "identity_secret": "922538810348594125658702672067738675294669207539999802857585668079702330450",
-              "path_elements": [
-                  "16059714054680148404543504061485737353203416489071538960876865983954285286166",
-                  "3041470753871943901334053763207316028823782848445723460227667780327106380356",
-                  "2557297527793326315072058421057853700096944625924483912548759909801348042183",
-                  "6677578602456189582427063963562590713054668181987223110955234085327917303436",
-                  "2250827150965576973906150764756422151438812678308727218463995574869267980301",
-                  "1895457427602709606993445561553433669787657053834360973759981803464906070980",
-                  "11033689991077061346803816826729204895841441316315304395980565540264104346466",
-                  "18588752216879570844240300406954267039026327526134910835334500497981810174976",
-                  "19346480964028499661277403659363466542857230928032088490855656809181891953123",
-                  "21460193770370072688835316363068413651465631481105148051902686770759127189327",
-                  "20906347653364838502964722817589315918082261023317339146393355650507243340078",
-                  "13466599592974387800162739317046838825289754472645703919149409009404541432954",
-                  "9617165663598957201253074168824246164494443748556931540348223968573884172285",
-                  "6936463137584425684797785981770877165377386163416057257854261010817156666898",
-                  "369902028235468424790098825415813437044876310542601948037281422841675126849",
-                  "13510969869821080499683463562609720931680005714401083864659516045615497273644",
-                  "2567921390740781421487331055530491683313154421589525170472201828596388395736",
-                  "14360870889466292805403568662660511177232987619663547772298178013674025998478",
-                  "4735344599616284973799984501493858013178071155960162022656706545116168334293"
-              ],
-              "identity_path_index": [
-                  1,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0
-              ],
-              "x": "6427050788896290028100534859169645070970780055911091444144195464808120686416",
-              "epoch": "0x2bd155d9f85c741044da6909d144f9cc5ce8e0d545a9ed4921b156e8b8569bab",
-              "rln_identifier": "2193983000213424579594329476781986065965849144986973472766961413131458022566"
-            }
-        "#;
-
-    const WITNESS_JSON_20: &str = r#"
-            {
-              "identity_secret": "13732353453861280511150022598793312186188599006979552959297495195757997428306",
-              "path_elements": [
-                  "20463525608687844300981085488128968694844212760055234622292326942405619575964",
-                  "8040856403709217901175408904825741112286158901303127670929462145501210871313",
-                  "3776499751255585163563840252112871568402966629435152937692711318702338789837",
-                  "19415813252626942110541463414404411443562242499365750694284604341271149125679",
-                  "19414720788761208006634240390286942738242262010168559813148115573784354129237",
-                  "17680594732844291740094158892269696200077963275550625226493856898849422516043",
-                  "16009199741350632715210088346611798597033333293348807000623441780059543674510",
-                  "18743496911007535170857676824393811326863602477260615792503039058813338644738",
-                  "1029572792321380246989475723806770724699749375691788486434716005338938722216",
-                  "21713138150151063186050010182615713685603650963220209951496401043119768920892",
-                  "6713732504049401389983008178456811894856018247924860823028704114266363984580",
-                  "2746686888799473963221285145390361693256731812094259845879519459924507786594",
-                  "18620748467731297359505500266677881218553438497271819903304075323783392031715",
-                  "2446201221122671119406471414204229600430018713181038717206670749886932158104",
-                  "12037171942017611311954851302868199608036334625783560875426350283156617524597",
-                  "21798743392351780927808323348278035105395367759688979232116905142049921734349",
-                  "17450230289417496971557215666910229260621413088991137405744457922069827319039",
-                  "20936854099128086256353520300046664152516566958630447858438908748907198510485",
-                  "13513344965831154386658059617477268600255664386844920822248038939666265737046",
-                  "15546319496880899251450021422131511560001766832580480193115646510655765306630"
-
-              ],
-              "identity_path_index": [
-                  0,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0
-              ],
-              "x": "18073935665561339809445069958310044423750771681863480888589546877024349720547",
-              "epoch": "0x147e4c23a43a1ddca78d94bcd28147f62ca74b3dc7e56bb0a314a954b9f0e567",
-              "rln_identifier": "2193983000213424579594329476781986065965849144986973472766961413131458022566"
-            }
-        "#;
-
-    #[test]
-    // We test Merkle tree generation, proofs and verification
-    fn test_merkle_proof() {
-        let tree_height = TEST_TREE_HEIGHT;
-        let leaf_index = 3;
-
-        // generate identity
-        let identity_secret = hash_to_field(b"test-merkle-proof");
-        let id_commitment = poseidon_hash(&vec![identity_secret]);
-
-        // generate merkle tree
-        let default_leaf = Fr::from(0);
-        let mut tree = PoseidonTree::new(tree_height, default_leaf);
-        tree.set(leaf_index, id_commitment.into()).unwrap();
-
-        // We check correct computation of the root
-        let root = tree.root();
-
-        if TEST_TREE_HEIGHT == 15 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x1984f2e01184aef5cb974640898a5f5c25556554e2b06d99d4841badb8b198cd",
-                    16
-                )
-            );
-        } else if TEST_TREE_HEIGHT == 19 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x219ceb53f2b1b7a6cf74e80d50d44d68ecb4a53c6cc65b25593c8d56343fb1fe",
-                    16
-                )
-            );
-        } else if TEST_TREE_HEIGHT == 20 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x21947ffd0bce0c385f876e7c97d6a42eec5b1fe935aab2f01c1f8a8cbcc356d2",
-                    16
-                )
-            );
-        }
-
-        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
-        let path_elements = merkle_proof.get_path_elements();
-        let identity_path_index = merkle_proof.get_path_index();
-
-        // We check correct computation of the path and indexes
-        // These values refers to TEST_TREE_HEIGHT == 16
-        let mut expected_path_elements = vec![
-            str_to_fr(
-                "0x0000000000000000000000000000000000000000000000000000000000000000",
-                16,
-            ),
-            str_to_fr(
-                "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
-                16,
-            ),
-            str_to_fr(
-                "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
-                16,
-            ),
-            str_to_fr(
-                "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
-                16,
-            ),
-            str_to_fr(
-                "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
-                16,
-            ),
-            str_to_fr(
-                "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
-                16,
-            ),
-            str_to_fr(
-                "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
-                16,
-            ),
-            str_to_fr(
-                "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
-                16,
-            ),
-            str_to_fr(
-                "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
-                16,
-            ),
-            str_to_fr(
-                "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
-                16,
-            ),
-            str_to_fr(
-                "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
-                16,
-            ),
-            str_to_fr(
-                "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
-                16,
-            ),
-            str_to_fr(
-                "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
-                16,
-            ),
-            str_to_fr(
-                "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
-                16,
-            ),
-            str_to_fr(
-                "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
-                16,
-            ),
-        ];
-
-        let mut expected_identity_path_index: Vec<u8> =
-            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
-
-        // We add the remaining elements for the case TEST_TREE_HEIGHT = 20
-        if TEST_TREE_HEIGHT == 19 || TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![
-                str_to_fr(
-                    "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
-                    16,
-                ),
-                str_to_fr(
-                    "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
-                    16,
-                ),
-                str_to_fr(
-                    "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
-                    16,
-                ),
-                str_to_fr(
-                    "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
-                    16,
-                ),
-            ]);
-            expected_identity_path_index.append(&mut vec![0, 0, 0, 0]);
-        }
-
-        if TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![str_to_fr(
-                "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
-                16,
-            )]);
-            expected_identity_path_index.append(&mut vec![0]);
-        }
-
-        assert_eq!(path_elements, expected_path_elements);
-        assert_eq!(identity_path_index, expected_identity_path_index);
-
-        // We check correct verification of the proof
-        assert!(tree.verify(&id_commitment, &merkle_proof).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(TEST_RESOURCES_FOLDER).unwrap();
-        let verification_key = vk_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let builder = circom_from_folder(TEST_RESOURCES_FOLDER);
-
-        // We compute witness from the json input example
-        let mut witness_json: &str = "";
-
-        if TEST_TREE_HEIGHT == 15 {
-            witness_json = WITNESS_JSON_15;
-        } else if TEST_TREE_HEIGHT == 19 {
-            witness_json = WITNESS_JSON_19;
-        } else if TEST_TREE_HEIGHT == 20 {
-            witness_json = WITNESS_JSON_20;
-        }
-
-        let rln_witness = rln_witness_from_json(witness_json);
-
-        // Let's generate a zkSNARK proof
-        let proof = generate_proof(builder, &proving_key, &rln_witness).unwrap();
-
-        let proof_values = proof_values_from_witness(&rln_witness);
-
-        // 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 tree_height = TEST_TREE_HEIGHT;
-        let leaf_index = 3;
-
-        // Generate identity pair
-        let (identity_secret, id_commitment) = keygen();
-
-        //// generate merkle tree
-        let default_leaf = Fr::from(0);
-        let mut tree = PoseidonTree::new(tree_height, default_leaf);
-        tree.set(leaf_index, id_commitment.into()).unwrap();
-
-        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
-
-        let signal = b"hey hey";
-        let x = hash_to_field(signal);
-
-        // 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 rln_witness: RLNWitnessInput = rln_witness_from_values(
-            identity_secret,
-            &merkle_proof,
-            x,
-            epoch, /*, rln_identifier*/
-        );
-
-        // We generate all relevant keys
-        let proving_key = zkey_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let verification_key = vk_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let builder = circom_from_folder(TEST_RESOURCES_FOLDER);
-
-        // Let's generate a zkSNARK proof
-        let proof = generate_proof(builder, &proving_key, &rln_witness).unwrap();
-
-        let proof_values = proof_values_from_witness(&rln_witness);
-
-        // Let's verify the proof
-        let success = verify_proof(&verification_key, &proof, &proof_values).unwrap();
-
-        assert!(success);
-    }
-
-    #[test]
-    fn test_witness_serialization() {
-        // We test witness serialization
-        let mut witness_json: &str = "";
-
-        if TEST_TREE_HEIGHT == 15 {
-            witness_json = WITNESS_JSON_15;
-        } else if TEST_TREE_HEIGHT == 19 {
-            witness_json = WITNESS_JSON_19;
-        } else if TEST_TREE_HEIGHT == 20 {
-            witness_json = WITNESS_JSON_20;
-        }
-
-        let rln_witness = rln_witness_from_json(witness_json);
-
-        let ser = serialize_witness(&rln_witness);
-        let (deser, _) = deserialize_witness(&ser);
-        assert_eq!(rln_witness, deser);
-
-        // We test Proof values serialization
-        let proof_values = proof_values_from_witness(&rln_witness);
-        let ser = serialize_proof_values(&proof_values);
-        let (deser, _) = deserialize_proof_values(&ser);
-        assert_eq!(proof_values, deser);
-    }
-}
+// 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/merkle_tree.rs

@@ -1,666 +0,0 @@
-// This crate provides different implementation of Merkle tree
-// Currently two interchangeable implementations are supported:
-//    - FullMerkleTree: each tree node is stored
-//    - OptimalMerkleTree: only nodes used to prove accumulation of set leaves are stored
-// Library defaults are set in the poseidon_tree crate
-//
-// Merkle tree implementations are adapted from https://github.com/kilic/rln/blob/master/src/merkle.rs
-// and https://github.com/worldcoin/semaphore-rs/blob/d462a4372f1fd9c27610f2acfe4841fab1d396aa/src/merkle_tree.rs
-
-//!
-//! # To do
-//!
-//! * Disk based storage backend (using mmaped files should be easy)
-//! * Implement serialization for tree and Merkle proof
-
-use std::collections::HashMap;
-use std::io;
-use std::{
-    cmp::max,
-    fmt::Debug,
-    iter::{once, repeat, successors},
-};
-
-/// In the Hasher trait we define the node type, the default leaf
-/// and the hash function used to initialize a Merkle Tree implementation
-pub trait Hasher {
-    /// Type of the leaf and tree node
-    type Fr: Copy + Clone + Eq;
-
-    /// Returns the default tree leaf
-    fn default_leaf() -> Self::Fr;
-
-    /// Utility to compute the hash of an intermediate node
-    fn hash(input: &[Self::Fr]) -> Self::Fr;
-}
-
-////////////////////////////////////////////////////////////
-/// Optimal Merkle Tree Implementation
-////////////////////////////////////////////////////////////
-
-/// The Merkle tree structure
-#[derive(Clone, PartialEq, Eq, Debug)]
-pub struct OptimalMerkleTree<H>
-where
-    H: Hasher,
-{
-    /// The depth of the tree, i.e. the number of levels from leaf to root
-    depth: usize,
-
-    /// The nodes cached from the empty part of the tree (where leaves are set to default).
-    /// Since the rightmost part of the tree is usually changed much later than its creation,
-    /// we can prove accumulation of elements in the leftmost part, with no need to initialize the full tree
-    /// and by caching few intermediate nodes to the root computed from default leaves
-    cached_nodes: Vec<H::Fr>,
-
-    /// The tree nodes
-    nodes: HashMap<(usize, usize), H::Fr>,
-
-    // The next available (i.e., never used) tree index. Equivalently, the number of leaves added to the tree
-    // (deletions leave next_index unchanged)
-    next_index: usize,
-}
-
-/// The Merkle proof
-/// Contains a vector of (node, branch_index) that defines the proof path elements and branch direction (1 or 0)
-#[derive(Clone, PartialEq, Eq)]
-pub struct OptimalMerkleProof<H: Hasher>(pub Vec<(H::Fr, u8)>);
-
-/// Implementations
-
-impl<H: Hasher> OptimalMerkleTree<H> {
-    pub fn default(depth: usize) -> Self {
-        OptimalMerkleTree::<H>::new(depth, H::default_leaf())
-    }
-
-    /// Creates a new `MerkleTree`
-    /// depth - the height of the tree made only of hash nodes. 2^depth is the maximum number of leaves hash nodes
-    pub fn new(depth: usize, default_leaf: H::Fr) -> Self {
-        let mut cached_nodes: Vec<H::Fr> = Vec::with_capacity(depth + 1);
-        cached_nodes.push(default_leaf);
-        for i in 0..depth {
-            cached_nodes.push(H::hash(&[cached_nodes[i]; 2]));
-        }
-        cached_nodes.reverse();
-        OptimalMerkleTree {
-            cached_nodes: cached_nodes.clone(),
-            depth: depth,
-            nodes: HashMap::new(),
-            next_index: 0,
-        }
-    }
-
-    // Returns the depth of the tree
-    pub fn depth(&self) -> usize {
-        self.depth
-    }
-
-    // Returns the capacity of the tree, i.e. the maximum number of accumulatable leaves
-    pub fn capacity(&self) -> usize {
-        1 << self.depth
-    }
-
-    // Returns the total number of leaves set
-    pub fn leaves_set(&mut self) -> usize {
-        self.next_index
-    }
-
-    #[must_use]
-    // Returns the root of the tree
-    pub fn root(&self) -> H::Fr {
-        self.get_node(0, 0)
-    }
-
-    // Sets a leaf at the specified tree index
-    pub fn set(&mut self, index: usize, leaf: H::Fr) -> io::Result<()> {
-        if index >= self.capacity() {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "index exceeds set size",
-            ));
-        }
-        self.nodes.insert((self.depth, index), leaf);
-        self.recalculate_from(index);
-        self.next_index = max(self.next_index, index + 1);
-        Ok(())
-    }
-
-    // Sets a leaf at the next available index
-    pub fn update_next(&mut self, leaf: H::Fr) -> io::Result<()> {
-        self.set(self.next_index, leaf)?;
-        Ok(())
-    }
-
-    // Deletes a leaf at a certain index by setting it to its default value (next_index is not updated)
-    pub fn delete(&mut self, index: usize) -> io::Result<()> {
-        // We reset the leaf only if we previously set a leaf at that index
-        if index < self.next_index {
-            self.set(index, H::default_leaf())?;
-        }
-        Ok(())
-    }
-
-    // Computes a merkle proof the the leaf at the specified index
-    pub fn proof(&self, index: usize) -> io::Result<OptimalMerkleProof<H>> {
-        if index >= self.capacity() {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "index exceeds set size",
-            ));
-        }
-        let mut witness = Vec::<(H::Fr, u8)>::with_capacity(self.depth);
-        let mut i = index;
-        let mut depth = self.depth;
-        loop {
-            i ^= 1;
-            witness.push((self.get_node(depth, i), (1 - (i & 1)).try_into().unwrap()));
-            i >>= 1;
-            depth -= 1;
-            if depth == 0 {
-                break;
-            }
-        }
-        assert_eq!(i, 0);
-        Ok(OptimalMerkleProof(witness))
-    }
-
-    // Verifies a Merkle proof with respect to the input leaf and the tree root
-    pub fn verify(&self, leaf: &H::Fr, witness: &OptimalMerkleProof<H>) -> io::Result<bool> {
-        if witness.length() != self.depth {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "witness length doesn't match tree depth",
-            ));
-        }
-        let expected_root = witness.compute_root_from(leaf);
-        Ok(expected_root.eq(&self.root()))
-    }
-
-    // Utilities for updating the tree nodes
-
-    fn get_node(&self, depth: usize, index: usize) -> H::Fr {
-        let node = *self
-            .nodes
-            .get(&(depth, index))
-            .unwrap_or_else(|| &self.cached_nodes[depth]);
-        node
-    }
-
-    fn get_leaf(&self, index: usize) -> H::Fr {
-        self.get_node(self.depth, index)
-    }
-
-    fn hash_couple(&mut self, depth: usize, index: usize) -> H::Fr {
-        let b = index & !1;
-        H::hash(&[self.get_node(depth, b), self.get_node(depth, b + 1)])
-    }
-
-    fn recalculate_from(&mut self, index: usize) {
-        let mut i = index;
-        let mut depth = self.depth;
-        loop {
-            let h = self.hash_couple(depth, i);
-            i >>= 1;
-            depth -= 1;
-            self.nodes.insert((depth, i), h);
-            if depth == 0 {
-                break;
-            }
-        }
-        assert_eq!(depth, 0);
-        assert_eq!(i, 0);
-    }
-}
-
-impl<H: Hasher> OptimalMerkleProof<H> {
-    #[must_use]
-    // Returns the length of a Merkle proof
-    pub fn length(&self) -> usize {
-        self.0.len()
-    }
-
-    /// Computes the leaf index corresponding to a Merkle proof
-    #[must_use]
-    pub fn leaf_index(&self) -> usize {
-        // In current implementation the path indexes in a proof correspond to the binary representation of the leaf index
-        let mut binary_repr = self.get_path_index();
-        binary_repr.reverse();
-        binary_repr
-            .into_iter()
-            .fold(0, |acc, digit| (acc << 1) + usize::from(digit))
-    }
-
-    #[must_use]
-    /// Returns the path elements forming a Merkle proof
-    pub fn get_path_elements(&self) -> Vec<H::Fr> {
-        self.0.iter().map(|x| x.0).collect()
-    }
-
-    /// Returns the path indexes forming a Merkle proof
-    #[must_use]
-    pub fn get_path_index(&self) -> Vec<u8> {
-        self.0.iter().map(|x| x.1).collect()
-    }
-
-    #[must_use]
-    /// Computes the Merkle root corresponding by iteratively hashing a Merkle proof with a given input leaf
-    pub fn compute_root_from(&self, leaf: &H::Fr) -> H::Fr {
-        let mut acc: H::Fr = *leaf;
-        for w in self.0.iter() {
-            if w.1 == 0 {
-                acc = H::hash(&[acc, w.0]);
-            } else {
-                acc = H::hash(&[w.0, acc]);
-            }
-        }
-        acc
-    }
-}
-
-// Debug formatting for printing a (Optimal) Merkle Proof
-impl<H> Debug for OptimalMerkleProof<H>
-where
-    H: Hasher,
-    H::Fr: Debug,
-{
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.debug_tuple("Proof").field(&self.0).finish()
-    }
-}
-
-////////////////////////////////////////////////////////////
-/// Full Merkle Tree Implementation
-////////////////////////////////////////////////////////////
-
-/// Merkle tree with all leaf and intermediate hashes stored
-#[derive(Clone, PartialEq, Eq, Debug)]
-pub struct FullMerkleTree<H: Hasher> {
-    /// The depth of the tree, i.e. the number of levels from leaf to root
-    depth: usize,
-
-    /// The nodes cached from the empty part of the tree (where leaves are set to default).
-    /// Since the rightmost part of the tree is usually changed much later than its creation,
-    /// we can prove accumulation of elements in the leftmost part, with no need to initialize the full tree
-    /// and by caching few intermediate nodes to the root computed from default leaves
-    cached_nodes: Vec<H::Fr>,
-
-    /// The tree nodes
-    nodes: Vec<H::Fr>,
-
-    // The next available (i.e., never used) tree index. Equivalently, the number of leaves added to the tree
-    // (deletions leave next_index unchanged)
-    next_index: usize,
-}
-
-/// Element of a Merkle proof
-#[derive(Clone, Copy, PartialEq, Eq)]
-pub enum FullMerkleBranch<H: Hasher> {
-    /// Left branch taken, value is the right sibling hash.
-    Left(H::Fr),
-
-    /// Right branch taken, value is the left sibling hash.
-    Right(H::Fr),
-}
-
-/// Merkle proof path, bottom to top.
-#[derive(Clone, PartialEq, Eq)]
-pub struct FullMerkleProof<H: Hasher>(pub Vec<FullMerkleBranch<H>>);
-
-/// Implementations
-
-impl<H: Hasher> FullMerkleTree<H> {
-    pub fn default(depth: usize) -> Self {
-        FullMerkleTree::<H>::new(depth, H::default_leaf())
-    }
-
-    /// Creates a new `MerkleTree`
-    /// depth - the height of the tree made only of hash nodes. 2^depth is the maximum number of leaves hash nodes
-    pub fn new(depth: usize, initial_leaf: H::Fr) -> Self {
-        // Compute cache node values, leaf to root
-        let cached_nodes = successors(Some(initial_leaf), |prev| Some(H::hash(&[*prev, *prev])))
-            .take(depth + 1)
-            .collect::<Vec<_>>();
-
-        // Compute node values
-        let nodes = cached_nodes
-            .iter()
-            .rev()
-            .enumerate()
-            .flat_map(|(levels, hash)| repeat(hash).take(1 << levels))
-            .cloned()
-            .collect::<Vec<_>>();
-        debug_assert!(nodes.len() == (1 << (depth + 1)) - 1);
-
-        let next_index = 0;
-
-        Self {
-            depth,
-            cached_nodes,
-            nodes,
-            next_index,
-        }
-    }
-
-    // Returns the depth of the tree
-    pub fn depth(&self) -> usize {
-        self.depth
-    }
-
-    // Returns the capacity of the tree, i.e. the maximum number of accumulatable leaves
-    pub fn capacity(&self) -> usize {
-        1 << self.depth
-    }
-
-    // Returns the total number of leaves set
-    pub fn leaves_set(&mut self) -> usize {
-        self.next_index
-    }
-
-    #[must_use]
-    // Returns the root of the tree
-    pub fn root(&self) -> H::Fr {
-        self.nodes[0]
-    }
-
-    // Sets a leaf at the specified tree index
-    pub fn set(&mut self, leaf: usize, hash: H::Fr) -> io::Result<()> {
-        self.set_range(leaf, once(hash))?;
-        self.next_index = max(self.next_index, leaf + 1);
-        Ok(())
-    }
-
-    // Sets tree nodes, starting from start index
-    // Function proper of FullMerkleTree implementation
-    fn set_range<I: IntoIterator<Item = H::Fr>>(
-        &mut self,
-        start: usize,
-        hashes: I,
-    ) -> io::Result<()> {
-        let index = self.capacity() + start - 1;
-        let mut count = 0;
-        // TODO: Error/panic when hashes is longer than available leafs
-        for (leaf, hash) in self.nodes[index..].iter_mut().zip(hashes) {
-            *leaf = hash;
-            count += 1;
-        }
-        if count != 0 {
-            self.update_nodes(index, index + (count - 1));
-            self.next_index = max(self.next_index, start + count);
-        }
-        Ok(())
-    }
-
-    // Sets a leaf at the next available index
-    pub fn update_next(&mut self, leaf: H::Fr) -> io::Result<()> {
-        self.set(self.next_index, leaf)?;
-        Ok(())
-    }
-
-    // Deletes a leaf at a certain index by setting it to its default value (next_index is not updated)
-    pub fn delete(&mut self, index: usize) -> io::Result<()> {
-        // We reset the leaf only if we previously set a leaf at that index
-        if index < self.next_index {
-            self.set(index, H::default_leaf())?;
-        }
-        Ok(())
-    }
-
-    // Computes a merkle proof the the leaf at the specified index
-    pub fn proof(&self, leaf: usize) -> io::Result<FullMerkleProof<H>> {
-        if leaf >= self.capacity() {
-            return Err(io::Error::new(
-                io::ErrorKind::InvalidInput,
-                "index exceeds set size",
-            ));
-        }
-        let mut index = self.capacity() + leaf - 1;
-        let mut path = Vec::with_capacity(self.depth + 1);
-        while let Some(parent) = self.parent(index) {
-            // Add proof for node at index to parent
-            path.push(match index & 1 {
-                1 => FullMerkleBranch::Left(self.nodes[index + 1]),
-                0 => FullMerkleBranch::Right(self.nodes[index - 1]),
-                _ => unreachable!(),
-            });
-            index = parent;
-        }
-        Ok(FullMerkleProof(path))
-    }
-
-    // Verifies a Merkle proof with respect to the input leaf and the tree root
-    pub fn verify(&self, hash: &H::Fr, proof: &FullMerkleProof<H>) -> io::Result<bool> {
-        Ok(proof.compute_root_from(hash) == self.root())
-    }
-
-    // Utilities for updating the tree nodes
-
-    /// For a given node index, return the parent node index
-    /// Returns None if there is no parent (root node)
-    fn parent(&self, index: usize) -> Option<usize> {
-        if index == 0 {
-            None
-        } else {
-            Some(((index + 1) >> 1) - 1)
-        }
-    }
-
-    /// For a given node index, return index of the first (left) child.
-    fn first_child(&self, index: usize) -> usize {
-        (index << 1) + 1
-    }
-
-    fn levels(&self, index: usize) -> usize {
-        // `n.next_power_of_two()` will return `n` iff `n` is a power of two.
-        // The extra offset corrects this.
-        (index + 2).next_power_of_two().trailing_zeros() as usize - 1
-    }
-
-    fn update_nodes(&mut self, start: usize, end: usize) {
-        debug_assert_eq!(self.levels(start), self.levels(end));
-        if let (Some(start), Some(end)) = (self.parent(start), self.parent(end)) {
-            for parent in start..=end {
-                let child = self.first_child(parent);
-                self.nodes[parent] = H::hash(&[self.nodes[child], self.nodes[child + 1]]);
-            }
-            self.update_nodes(start, end);
-        }
-    }
-}
-
-impl<H: Hasher> FullMerkleProof<H> {
-    #[must_use]
-    // Returns the length of a Merkle proof
-    pub fn length(&self) -> usize {
-        self.0.len()
-    }
-
-    /// Computes the leaf index corresponding to a Merkle proof
-    #[must_use]
-    pub fn leaf_index(&self) -> usize {
-        self.0.iter().rev().fold(0, |index, branch| match branch {
-            FullMerkleBranch::Left(_) => index << 1,
-            FullMerkleBranch::Right(_) => (index << 1) + 1,
-        })
-    }
-
-    #[must_use]
-    /// Returns the path elements forming a Merkle proof
-    pub fn get_path_elements(&self) -> Vec<H::Fr> {
-        self.0
-            .iter()
-            .map(|x| match x {
-                FullMerkleBranch::Left(value) | FullMerkleBranch::Right(value) => *value,
-            })
-            .collect()
-    }
-
-    /// Returns the path indexes forming a Merkle proof
-    #[must_use]
-    pub fn get_path_index(&self) -> Vec<u8> {
-        self.0
-            .iter()
-            .map(|branch| match branch {
-                FullMerkleBranch::Left(_) => 0,
-                FullMerkleBranch::Right(_) => 1,
-            })
-            .collect()
-    }
-
-    /// Computes the Merkle root corresponding by iteratively hashing a Merkle proof with a given input leaf
-    #[must_use]
-    pub fn compute_root_from(&self, hash: &H::Fr) -> H::Fr {
-        self.0.iter().fold(*hash, |hash, branch| match branch {
-            FullMerkleBranch::Left(sibling) => H::hash(&[hash, *sibling]),
-            FullMerkleBranch::Right(sibling) => H::hash(&[*sibling, hash]),
-        })
-    }
-}
-
-// Debug formatting for printing a (Full) Merkle Proof Branch
-impl<H> Debug for FullMerkleBranch<H>
-where
-    H: Hasher,
-    H::Fr: Debug,
-{
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        match self {
-            Self::Left(arg0) => f.debug_tuple("Left").field(arg0).finish(),
-            Self::Right(arg0) => f.debug_tuple("Right").field(arg0).finish(),
-        }
-    }
-}
-
-// Debug formatting for printing a (Full) Merkle Proof
-impl<H> Debug for FullMerkleProof<H>
-where
-    H: Hasher,
-    H::Fr: Debug,
-{
-    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        f.debug_tuple("Proof").field(&self.0).finish()
-    }
-}
-
-////////////////////////////////////////////////////////////
-/// Tests
-////////////////////////////////////////////////////////////
-
-// Tests adapted from https://github.com/worldcoin/semaphore-rs/blob/d462a4372f1fd9c27610f2acfe4841fab1d396aa/src/merkle_tree.rs
-#[cfg(test)]
-mod test {
-    use super::*;
-    use hex_literal::hex;
-    use tiny_keccak::{Hasher as _, Keccak};
-
-    struct Keccak256;
-
-    impl Hasher for Keccak256 {
-        type Fr = [u8; 32];
-
-        fn default_leaf() -> Self::Fr {
-            [0; 32]
-        }
-
-        fn hash(inputs: &[Self::Fr]) -> Self::Fr {
-            let mut output = [0; 32];
-            let mut hasher = Keccak::v256();
-            for element in inputs {
-                hasher.update(element);
-            }
-            hasher.finalize(&mut output);
-            output
-        }
-    }
-
-    #[test]
-    fn test_root() {
-        let leaves = [
-            hex!("0000000000000000000000000000000000000000000000000000000000000001"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000002"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000003"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-        ];
-
-        let default_tree_root =
-            hex!("b4c11951957c6f8f642c4af61cd6b24640fec6dc7fc607ee8206a99e92410d30");
-
-        let roots = [
-            hex!("c1ba1812ff680ce84c1d5b4f1087eeb08147a4d510f3496b2849df3a73f5af95"),
-            hex!("893760ec5b5bee236f29e85aef64f17139c3c1b7ff24ce64eb6315fca0f2485b"),
-            hex!("222ff5e0b5877792c2bc1670e2ccd0c2c97cd7bb1672a57d598db05092d3d72c"),
-            hex!("a9bb8c3f1f12e9aa903a50c47f314b57610a3ab32f2d463293f58836def38d36"),
-        ];
-
-        let mut tree = FullMerkleTree::<Keccak256>::new(2, [0; 32]);
-        assert_eq!(tree.root(), default_tree_root);
-        for i in 0..leaves.len() {
-            tree.set(i, leaves[i]).unwrap();
-            assert_eq!(tree.root(), roots[i]);
-        }
-
-        let mut tree = OptimalMerkleTree::<Keccak256>::new(2, [0; 32]);
-        assert_eq!(tree.root(), default_tree_root);
-        for i in 0..leaves.len() {
-            tree.set(i, leaves[i]).unwrap();
-            assert_eq!(tree.root(), roots[i]);
-        }
-    }
-
-    #[test]
-    fn test_proof() {
-        let leaves = [
-            hex!("0000000000000000000000000000000000000000000000000000000000000001"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000002"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000003"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-        ];
-
-        // We thest the FullMerkleTree implementation
-        let mut tree = FullMerkleTree::<Keccak256>::new(2, [0; 32]);
-        for i in 0..leaves.len() {
-            // We set the leaves
-            tree.set(i, leaves[i]).unwrap();
-
-            // We compute a merkle proof
-            let proof = tree.proof(i).expect("index should be set");
-
-            // We verify if the merkle proof corresponds to the right leaf index
-            assert_eq!(proof.leaf_index(), i);
-
-            // We verify the proof
-            assert!(tree.verify(&leaves[i], &proof).unwrap());
-
-            // We ensure that the Merkle proof and the leaf generate the same root as the tree
-            assert_eq!(proof.compute_root_from(&leaves[i]), tree.root());
-
-            // We check that the proof is not valid for another leaf
-            assert!(!tree
-                .verify(&leaves[(i + 1) % leaves.len()], &proof)
-                .unwrap());
-        }
-
-        // We test the OptimalMerkleTree implementation
-        let mut tree = OptimalMerkleTree::<Keccak256>::new(2, [0; 32]);
-        for i in 0..leaves.len() {
-            // We set the leaves
-            tree.set(i, leaves[i]).unwrap();
-
-            // We compute a merkle proof
-            let proof = tree.proof(i).expect("index should be set");
-
-            // We verify if the merkle proof corresponds to the right leaf index
-            assert_eq!(proof.leaf_index(), i);
-
-            // We verify the proof
-            assert!(tree.verify(&leaves[i], &proof).unwrap());
-
-            // We ensure that the Merkle proof and the leaf generate the same root as the tree
-            assert_eq!(proof.compute_root_from(&leaves[i]), tree.root());
-
-            // We check that the proof is not valid for another leaf
-            assert!(!tree
-                .verify(&leaves[(i + 1) % leaves.len()], &proof)
-                .unwrap());
-        }
-    }
-}

rln/src/pm_tree_adapter.rs

@@ -0,0 +1,505 @@
+use serde_json::Value;
+use std::fmt::Debug;
+use std::path::PathBuf;
+use std::str::FromStr;
+use tempfile::Builder;
+
+use crate::circuit::Fr;
+use crate::hashers::{poseidon_hash, PoseidonHash};
+use crate::utils::{bytes_le_to_fr, fr_to_bytes_le};
+use utils::error::{FromConfigError, ZerokitMerkleTreeError};
+use utils::pmtree::tree::Key;
+use utils::pmtree::{Database, Hasher, PmtreeErrorKind};
+use utils::{pmtree, Config, Mode, SledDB, ZerokitMerkleProof, ZerokitMerkleTree};
+
+const METADATA_KEY: [u8; 8] = *b"metadata";
+
+pub struct PmTree {
+    tree: pmtree::MerkleTree<SledDB, PoseidonHash>,
+    /// The indices of leaves which are set into zero upto next_index.
+    /// Set to 0 if the leaf is empty and set to 1 in otherwise.
+    cached_leaves_indices: Vec<u8>,
+    // metadata that an application may use to store additional information
+    metadata: Vec<u8>,
+}
+
+pub struct PmTreeProof {
+    proof: pmtree::tree::MerkleProof<PoseidonHash>,
+}
+
+pub type FrOf<H> = <H as Hasher>::Fr;
+
+// The pmtree Hasher trait used by pmtree Merkle tree
+impl Hasher for PoseidonHash {
+    type Fr = Fr;
+
+    fn serialize(value: Self::Fr) -> pmtree::Value {
+        fr_to_bytes_le(&value)
+    }
+
+    fn deserialize(value: pmtree::Value) -> Self::Fr {
+        let (fr, _) = bytes_le_to_fr(&value);
+        fr
+    }
+
+    fn default_leaf() -> Self::Fr {
+        Fr::from(0)
+    }
+
+    fn hash(inputs: &[Self::Fr]) -> Self::Fr {
+        poseidon_hash(inputs)
+    }
+}
+
+fn default_tmp_path() -> PathBuf {
+    Builder::new()
+        .prefix("pmtree-")
+        .tempfile()
+        .expect("Failed to create temp file")
+        .into_temp_path()
+        .to_path_buf()
+}
+
+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 PmtreeConfigBuilder {
+    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 PmtreeConfig {
+    pub fn builder() -> PmtreeConfigBuilder {
+        PmtreeConfigBuilder::new()
+    }
+}
+
+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();
+        let path = path.map(PathBuf::from);
+        let temporary = config["temporary"].as_bool();
+        let cache_capacity = config["cache_capacity"].as_u64();
+        let flush_every_ms = config["flush_every_ms"].as_u64();
+        let mode = match config["mode"].as_str() {
+            Some("HighThroughput") => Mode::HighThroughput,
+            Some("LowSpace") => Mode::LowSpace,
+            _ => Mode::HighThroughput,
+        };
+        let use_compression = config["use_compression"].as_bool();
+
+        if let (Some(true), Some(path)) = (temporary, path.as_ref()) {
+            if path.exists() {
+                return Err(FromConfigError::PathExists);
+            }
+        }
+
+        let config = Config::new()
+            .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));
+        Ok(PmtreeConfig(config))
+    }
+}
+
+impl Default for PmtreeConfig {
+    fn default() -> Self {
+        Self::builder()
+            .build()
+            .expect("Default configuration should never fail")
+    }
+}
+impl Debug for PmtreeConfig {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.0.fmt(f)
+    }
+}
+
+impl Clone for PmtreeConfig {
+    fn clone(&self) -> Self {
+        PmtreeConfig(self.0.clone())
+    }
+}
+
+impl ZerokitMerkleTree for PmTree {
+    type Proof = PmTreeProof;
+    type Hasher = PoseidonHash;
+    type Config = PmtreeConfig;
+
+    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, ZerokitMerkleTreeError> {
+        let tree_loaded = pmtree::MerkleTree::load(config.clone().0);
+        let tree = match tree_loaded {
+            Ok(tree) => tree,
+            Err(_) => pmtree::MerkleTree::new(depth, config.0)?,
+        };
+
+        Ok(PmTree {
+            tree,
+            cached_leaves_indices: vec![0; 1 << depth],
+            metadata: Vec::new(),
+        })
+    }
+
+    fn depth(&self) -> usize {
+        self.tree.depth()
+    }
+
+    fn capacity(&self) -> usize {
+        self.tree.capacity()
+    }
+
+    fn leaves_set(&self) -> usize {
+        self.tree.leaves_set()
+    }
+
+    fn root(&self) -> FrOf<Self::Hasher> {
+        self.tree.root()
+    }
+
+    fn set(
+        &mut self,
+        index: usize,
+        leaf: FrOf<Self::Hasher>,
+    ) -> Result<(), ZerokitMerkleTreeError> {
+        self.tree.set(index, leaf)?;
+        self.cached_leaves_indices[index] = 1;
+        Ok(())
+    }
+
+    fn set_range<I: IntoIterator<Item = FrOf<Self::Hasher>>>(
+        &mut self,
+        start: usize,
+        values: I,
+    ) -> Result<(), ZerokitMerkleTreeError> {
+        let v = values.into_iter().collect::<Vec<_>>();
+        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>, ZerokitMerkleTreeError> {
+        self.tree
+            .get(index)
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
+    }
+
+    fn get_subtree_root(
+        &self,
+        n: usize,
+        index: usize,
+    ) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError> {
+        if n > self.depth() {
+            return Err(ZerokitMerkleTreeError::InvalidLevel);
+        }
+        if index >= self.capacity() {
+            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)
+        }
+    }
+
+    fn get_empty_leaves_indices(&self) -> Vec<usize> {
+        let next_idx = self.leaves_set();
+        self.cached_leaves_indices
+            .iter()
+            .take(next_idx)
+            .enumerate()
+            .filter(|&(_, &v)| v == 0u8)
+            .map(|(idx, _)| idx)
+            .collect()
+    }
+
+    fn override_range<I: IntoIterator<Item = FrOf<Self::Hasher>>, J: IntoIterator<Item = usize>>(
+        &mut self,
+        start: usize,
+        leaves: I,
+        indices: J,
+    ) -> 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(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)
+                .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<(), ZerokitMerkleTreeError> {
+        self.tree
+            .update_next(leaf)
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
+    }
+
+    /// 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(ZerokitMerkleTreeError::PmtreeErrorKind)?;
+        self.cached_leaves_indices[index] = 0;
+        Ok(())
+    }
+
+    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, ZerokitMerkleTreeError> {
+        if self.tree.verify(leaf, &witness.proof) {
+            Ok(true)
+        } else {
+            Err(ZerokitMerkleTreeError::InvalidWitness)
+        }
+    }
+
+    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>, 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())
+    }
+
+    fn close_db_connection(&mut self) -> Result<(), ZerokitMerkleTreeError> {
+        self.tree
+            .db
+            .close()
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
+    }
+}
+
+type PmTreeHasher = <PmTree as ZerokitMerkleTree>::Hasher;
+type FrOfPmTreeHasher = FrOf<PmTreeHasher>;
+
+impl PmTree {
+    fn remove_indices(&mut self, indices: &[usize]) -> Result<(), PmtreeErrorKind> {
+        let start = indices[0];
+        let end = indices.last().unwrap() + 1;
+
+        let new_leaves = (start..end).map(|_| PmTreeHasher::default_leaf());
+
+        self.tree.set_range(start, new_leaves)?;
+
+        for i in start..end {
+            self.cached_leaves_indices[i] = 0
+        }
+        Ok(())
+    }
+
+    fn remove_indices_and_set_leaves(
+        &mut self,
+        start: usize,
+        leaves: Vec<FrOfPmTreeHasher>,
+        indices: &[usize],
+    ) -> Result<(), PmtreeErrorKind> {
+        let min_index = *indices.first().unwrap();
+        let max_index = start + leaves.len();
+
+        let mut set_values = vec![PmTreeHasher::default_leaf(); max_index - min_index];
+
+        for i in min_index..start {
+            if !indices.contains(&i) {
+                let value = self.tree.get(i)?;
+                set_values[i - min_index] = value;
+            }
+        }
+
+        for (i, &leaf) in leaves.iter().enumerate() {
+            set_values[start - min_index + i] = leaf;
+        }
+
+        self.tree.set_range(start, set_values)?;
+
+        for i in indices {
+            self.cached_leaves_indices[*i] = 0;
+        }
+
+        for i in start..(max_index - min_index) {
+            self.cached_leaves_indices[i] = 1
+        }
+        Ok(())
+    }
+}
+
+impl ZerokitMerkleProof for PmTreeProof {
+    type Index = u8;
+    type Hasher = PoseidonHash;
+
+    fn length(&self) -> usize {
+        self.proof.length()
+    }
+
+    fn leaf_index(&self) -> usize {
+        self.proof.leaf_index()
+    }
+
+    fn get_path_elements(&self) -> Vec<FrOf<Self::Hasher>> {
+        self.proof.get_path_elements()
+    }
+
+    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)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    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().expect("Failed to parse JSON config");
+
+        let _ = PmtreeConfig::builder()
+            .path(default_tmp_path())
+            .temporary(DEFAULT_TEMPORARY)
+            .cache_capacity(DEFAULT_CACHE_CAPACITY)
+            .mode(DEFAULT_MODE)
+            .use_compression(DEFAULT_USE_COMPRESSION)
+            .build()
+            .expect("Failed to build config");
+    }
+}

rln/src/poseidon_hash.rs

@@ -1,129 +0,0 @@
-// This crate implements the Poseidon hash algorithm https://eprint.iacr.org/2019/458.pdf
-
-// The implementation is taken from https://github.com/arnaucube/poseidon-rs/blob/233027d6075a637c29ad84a8a44f5653b81f0410/src/lib.rs
-// and slightly adapted to work over arkworks field data type
-
-use crate::circuit::Fr;
-use crate::poseidon_constants::constants;
-use crate::utils::*;
-use ark_std::Zero;
-use once_cell::sync::Lazy;
-
-#[derive(Debug)]
-pub struct Constants {
-    pub c: Vec<Vec<Fr>>,
-    pub m: Vec<Vec<Vec<Fr>>>,
-    pub n_rounds_f: usize,
-    pub n_rounds_p: Vec<usize>,
-}
-pub fn load_constants() -> Constants {
-    let (c_str, m_str) = constants();
-    let mut c: Vec<Vec<Fr>> = Vec::new();
-    for i in 0..c_str.len() {
-        let mut cci: Vec<Fr> = Vec::new();
-        for j in 0..c_str[i].len() {
-            let b: Fr = str_to_fr(c_str[i][j], 10);
-            cci.push(b);
-        }
-        c.push(cci);
-    }
-    let mut m: Vec<Vec<Vec<Fr>>> = Vec::new();
-    for i in 0..m_str.len() {
-        let mut mi: Vec<Vec<Fr>> = Vec::new();
-        for j in 0..m_str[i].len() {
-            let mut mij: Vec<Fr> = Vec::new();
-            for k in 0..m_str[i][j].len() {
-                let b: Fr = str_to_fr(m_str[i][j][k], 10);
-                mij.push(b);
-            }
-            mi.push(mij);
-        }
-        m.push(mi);
-    }
-    Constants {
-        c: c,
-        m: m,
-        n_rounds_f: 8,
-        n_rounds_p: vec![56, 57, 56, 60, 60, 63, 64, 63],
-    }
-}
-
-pub struct Poseidon {
-    constants: Constants,
-}
-impl Poseidon {
-    pub fn new() -> Poseidon {
-        Poseidon {
-            constants: load_constants(),
-        }
-    }
-    pub fn ark(&self, state: &mut [Fr], c: &[Fr], it: usize) {
-        for i in 0..state.len() {
-            state[i] += c[it + i];
-        }
-    }
-
-    pub fn sbox(&self, n_rounds_f: usize, n_rounds_p: usize, state: &mut [Fr], i: usize) {
-        if (i < n_rounds_f / 2) || (i >= n_rounds_f / 2 + n_rounds_p) {
-            for j in 0..state.len() {
-                let aux = state[j];
-                state[j] *= state[j];
-                state[j] *= state[j];
-                state[j] *= aux;
-            }
-        } else {
-            let aux = state[0];
-            state[0] *= state[0];
-            state[0] *= state[0];
-            state[0] *= aux;
-        }
-    }
-
-    pub fn mix(&self, state: &[Fr], m: &[Vec<Fr>]) -> Vec<Fr> {
-        let mut new_state: Vec<Fr> = Vec::new();
-        for i in 0..state.len() {
-            new_state.push(Fr::zero());
-            for j in 0..state.len() {
-                let mut mij = m[i][j];
-                mij *= state[j];
-                new_state[i] += mij;
-            }
-        }
-        new_state.clone()
-    }
-
-    pub fn hash(&self, inp: Vec<Fr>) -> Result<Fr, String> {
-        let t = inp.len() + 1;
-        if inp.is_empty() || (inp.len() >= self.constants.n_rounds_p.len() - 1) {
-            return Err("Wrong inputs length".to_string());
-        }
-        let n_rounds_f = self.constants.n_rounds_f;
-        let n_rounds_p = self.constants.n_rounds_p[t - 2];
-
-        let mut state = vec![Fr::zero(); t];
-        state[1..].clone_from_slice(&inp);
-
-        for i in 0..(n_rounds_f + n_rounds_p) {
-            self.ark(&mut state, &self.constants.c[t - 2], i * t);
-            self.sbox(n_rounds_f, n_rounds_p, &mut state, i);
-            state = self.mix(&state, &self.constants.m[t - 2]);
-        }
-
-        Ok(state[0])
-    }
-}
-
-impl Default for Poseidon {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-// Poseidon Hash wrapper over above implementation. Adapted from semaphore-rs poseidon hash wrapper.
-static POSEIDON: Lazy<Poseidon> = Lazy::new(Poseidon::new);
-
-pub fn poseidon_hash(input: &[Fr]) -> Fr {
-    POSEIDON
-        .hash(input.to_vec())
-        .expect("hash with fixed input size can't fail")
-}

rln/src/poseidon_tree.rs

@@ -1,109 +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 crate::circuit::Fr;
-use crate::merkle_tree::*;
-use crate::poseidon_hash::poseidon_hash;
 use cfg_if::cfg_if;
 
-// 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 utils::{FullMerkleTree, FullMerkleProof};
+        use crate::hashers::PoseidonHash;
+
         pub type PoseidonTree = FullMerkleTree<PoseidonHash>;
         pub type MerkleProof = FullMerkleProof<PoseidonHash>;
-    } else {
+    } else if #[cfg(feature = "optimalmerkletree")] {
+        use utils::{OptimalMerkleTree, OptimalMerkleProof};
+        use crate::hashers::PoseidonHash;
+
         pub type PoseidonTree = OptimalMerkleTree<PoseidonHash>;
         pub type MerkleProof = OptimalMerkleProof<PoseidonHash>;
-    }
-}
-
-// The zerokit RLN default Hasher
-#[derive(Clone, Copy, PartialEq, Eq)]
-pub struct PoseidonHash;
-
-impl Hasher for PoseidonHash {
-    type Fr = Fr;
-
-    fn default_leaf() -> Self::Fr {
-        Self::Fr::from(0)
-    }
-
-    fn hash(inputs: &[Self::Fr]) -> Self::Fr {
-        poseidon_hash(inputs)
-    }
-}
-
-////////////////////////////////////////////////////////////
-/// Tests
-////////////////////////////////////////////////////////////
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[test]
-    /// A basic performance comparison between the two supported Merkle Tree implementations
-    fn test_merkle_implementations_performances() {
-        use std::time::{Duration, Instant};
-
-        let tree_height = 20;
-        let sample_size = 100;
-
-        let leaves: Vec<Fr> = (0..sample_size).map(|s| Fr::from(s)).collect();
-
-        let mut gen_time_full: u128 = 0;
-        let mut upd_time_full: u128 = 0;
-        let mut gen_time_opt: u128 = 0;
-        let mut upd_time_opt: u128 = 0;
-
-        for _ in 0..sample_size.try_into().unwrap() {
-            let now = Instant::now();
-            FullMerkleTree::<PoseidonHash>::default(tree_height);
-            gen_time_full += now.elapsed().as_nanos();
-
-            let now = Instant::now();
-            OptimalMerkleTree::<PoseidonHash>::default(tree_height);
-            gen_time_opt += now.elapsed().as_nanos();
-        }
-
-        let mut tree_full = FullMerkleTree::<PoseidonHash>::default(tree_height);
-        let mut tree_opt = OptimalMerkleTree::<PoseidonHash>::default(tree_height);
-        for i in 0..sample_size.try_into().unwrap() {
-            let now = Instant::now();
-            tree_full.set(i, leaves[i]).unwrap();
-            upd_time_full += now.elapsed().as_nanos();
-            let proof = tree_full.proof(i).expect("index should be set");
-            assert_eq!(proof.leaf_index(), i);
-
-            let now = Instant::now();
-            tree_opt.set(i, leaves[i]).unwrap();
-            upd_time_opt += now.elapsed().as_nanos();
-            let proof = tree_opt.proof(i).expect("index should be set");
-            assert_eq!(proof.leaf_index(), i);
-        }
-
-        println!("Average tree generation time:");
-        println!(
-            "   - Full Merkle Tree:  {:?}",
-            Duration::from_nanos((gen_time_full / sample_size).try_into().unwrap())
-        );
-        println!(
-            "   - Optimal Merkle Tree: {:?}",
-            Duration::from_nanos((gen_time_opt / sample_size).try_into().unwrap())
-        );
-
-        println!("Average update_next execution time:");
-        println!(
-            "   - Full Merkle Tree: {:?}",
-            Duration::from_nanos((upd_time_full / sample_size).try_into().unwrap())
-        );
-
-        println!(
-            "   - Optimal Merkle Tree: {:?}",
-            Duration::from_nanos((upd_time_opt / sample_size).try_into().unwrap())
-        );
+    } else if #[cfg(feature = "pmtree-ft")] {
+        use crate::pm_tree_adapter::{PmTree, PmTreeProof};
+
+        pub type PoseidonTree = PmTree;
+        pub type MerkleProof = PmTreeProof;
+    } else {
+        compile_error!("One of the features `fullmerkletree`, `optimalmerkletree`, or `pmtree-ft` must be enabled.");
     }
 }

rln/src/utils.rs

@@ -1,30 +1,35 @@
 // This crate provides cross-module useful utilities (mainly type conversions) not necessarily specific to RLN
 
 use crate::circuit::Fr;
-use ark_ff::{BigInteger, FpParameters, PrimeField};
+use crate::error::ConversionError;
+use ark_ff::PrimeField;
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
+use ark_std::UniformRand;
 use num_bigint::{BigInt, BigUint};
 use num_traits::Num;
-use std::iter::Extend;
-
-pub fn modulus_bit_size() -> usize {
-    <Fr as PrimeField>::Params::MODULUS
-        .num_bits()
-        .try_into()
-        .unwrap()
-}
+use rand::Rng;
+use ruint::aliases::U256;
+use serde_json::json;
+use std::io::Cursor;
+use std::ops::Deref;
+use zeroize::{Zeroize, ZeroizeOnDrop, Zeroizing};
 
+#[inline(always)]
 pub fn to_bigint(el: &Fr) -> BigInt {
-    let res: BigUint = (*el).try_into().unwrap();
-    res.try_into().unwrap()
+    BigUint::from(*el).into()
 }
 
-pub fn fr_byte_size() -> usize {
-    let mbs = modulus_bit_size();
-    (mbs + 64 - (mbs % 64)) / 8
+#[inline(always)]
+pub const fn fr_byte_size() -> usize {
+    let mbs = <Fr as PrimeField>::MODULUS_BIT_SIZE;
+    ((mbs + 64 - (mbs % 64)) / 8) as usize
 }
 
-pub fn str_to_fr(input: &str, radix: u32) -> Fr {
-    assert!((radix == 10) || (radix == 16));
+#[inline(always)]
+pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr, ConversionError> {
+    if !(radix == 10 || radix == 16) {
+        return Err(ConversionError::WrongRadix);
+    }
 
     // We remove any quote present and we trim
     let single_quote: char = '\"';
@@ -32,19 +37,14 @@ pub fn str_to_fr(input: &str, radix: u32) -> Fr {
     input_clean = input_clean.trim().to_string();
 
     if radix == 10 {
-        BigUint::from_str_radix(&input_clean, radix)
-            .unwrap()
-            .try_into()
-            .unwrap()
+        Ok(BigUint::from_str_radix(&input_clean, radix)?.into())
     } else {
         input_clean = input_clean.replace("0x", "");
-        BigUint::from_str_radix(&input_clean, radix)
-            .unwrap()
-            .try_into()
-            .unwrap()
+        Ok(BigUint::from_str_radix(&input_clean, radix)?.into())
     }
 }
 
+#[inline(always)]
 pub fn bytes_le_to_fr(input: &[u8]) -> (Fr, usize) {
     let el_size = fr_byte_size();
     (
@@ -53,6 +53,7 @@ pub fn bytes_le_to_fr(input: &[u8]) -> (Fr, usize) {
     )
 }
 
+#[inline(always)]
 pub fn bytes_be_to_fr(input: &[u8]) -> (Fr, usize) {
     let el_size = fr_byte_size();
     (
@@ -61,252 +62,360 @@ pub fn bytes_be_to_fr(input: &[u8]) -> (Fr, usize) {
     )
 }
 
+#[inline(always)]
 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)
-    while res.len() != fr_byte_size() {
-        res.push(0);
-    }
+    res.resize(fr_byte_size(), 0);
     res
 }
 
+#[inline(always)]
 pub fn fr_to_bytes_be(input: &Fr) -> Vec<u8> {
     let input_biguint: BigUint = (*input).into();
     let mut res = input_biguint.to_bytes_be();
-    // BigUint conversion ignores most significant zero bytes. We restore them otherwise serialization might fail
-    // Fr elements are stored using 64 bits nimbs
-    while res.len() != fr_byte_size() {
-        res.insert(0, 0);
+    // 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> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(input.len().to_le_bytes().to_vec());
+    // 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_le(input.len()));
+
     // We store each element
-    input.iter().for_each(|el| bytes.extend(fr_to_bytes_le(el)));
+    for el in input {
+        bytes.extend_from_slice(&fr_to_bytes_le(el));
+    }
 
     bytes
 }
 
+#[inline(always)]
 pub fn vec_fr_to_bytes_be(input: &[Fr]) -> Vec<u8> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(input.len().to_be_bytes().to_vec());
+    // 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
-    input.iter().for_each(|el| bytes.extend(fr_to_bytes_be(el)));
+    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> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len()).unwrap().to_le_bytes().to_vec());
-    bytes.extend(input);
+    // 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_le(input.len()));
+
+    // We store the input
+    bytes.extend_from_slice(input);
+
     bytes
 }
 
-pub fn vec_u8_to_bytes_be(input: Vec<u8>) -> Vec<u8> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len()).unwrap().to_be_bytes().to_vec());
-    bytes.extend(input);
+#[inline(always)]
+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
 }
 
-pub fn bytes_le_to_vec_u8(input: &[u8]) -> (Vec<u8>, usize) {
+#[inline(always)]
+pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize), ConversionError> {
     let mut read: usize = 0;
-
-    let len = usize::try_from(u64::from_le_bytes(input[0..8].try_into().unwrap())).unwrap();
+    if input.len() < 8 {
+        return Err(ConversionError::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(ConversionError::InsufficientData {
+            expected: 8 + len,
+            actual: input.len(),
+        });
+    }
     let res = input[8..8 + len].to_vec();
     read += res.len();
-
-    (res, read)
+    Ok((res, read))
 }
 
-pub fn bytes_be_to_vec_u8(input: &[u8]) -> (Vec<u8>, usize) {
+#[inline(always)]
+pub fn bytes_be_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize), ConversionError> {
     let mut read: usize = 0;
-
-    let len = usize::try_from(u64::from_be_bytes(input[0..8].try_into().unwrap())).unwrap();
+    if input.len() < 8 {
+        return Err(ConversionError::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(ConversionError::InsufficientData {
+            expected: 8 + len,
+            actual: input.len(),
+        });
+    }
     let res = input[8..8 + len].to_vec();
-
     read += res.len();
-
-    (res, read)
+    Ok((res, read))
 }
 
-pub fn bytes_le_to_vec_fr(input: &[u8]) -> (Vec<Fr>, usize) {
+#[inline(always)]
+pub fn bytes_le_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize), ConversionError> {
     let mut read: usize = 0;
-    let mut res: Vec<Fr> = Vec::new();
-
-    let len = usize::try_from(u64::from_le_bytes(input[0..8].try_into().unwrap())).unwrap();
+    if input.len() < 8 {
+        return Err(ConversionError::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();
+    if input.len() < 8 + len * el_size {
+        return Err(ConversionError::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)].to_vec());
+        let (curr_el, _) = bytes_le_to_fr(&input[8 + el_size * i..8 + el_size * (i + 1)]);
         res.push(curr_el);
         read += el_size;
     }
-
-    (res, read)
+    Ok((res, read))
 }
 
-pub fn bytes_be_to_vec_fr(input: &[u8]) -> (Vec<Fr>, usize) {
+#[inline(always)]
+pub fn bytes_be_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize), ConversionError> {
     let mut read: usize = 0;
-    let mut res: Vec<Fr> = Vec::new();
-
-    let len = usize::try_from(u64::from_be_bytes(input[0..8].try_into().unwrap())).unwrap();
+    if input.len() < 8 {
+        return Err(ConversionError::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(ConversionError::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)].to_vec());
+        let (curr_el, _) = bytes_be_to_fr(&input[8 + el_size * i..8 + el_size * (i + 1)]);
         res.push(curr_el);
         read += el_size;
     }
-
-    (res, read)
+    Ok((res, read))
 }
 
-/* Old conversion utilities between different libraries data types
-
-// Conversion Utilities between poseidon-rs Field and arkworks Fr (in order to call directly poseidon-rs' poseidon_hash)
-
-use ff::{PrimeField as _, PrimeFieldRepr as _};
-use poseidon_rs::Fr as PosFr;
-
-pub fn fr_to_posfr(value: Fr) -> PosFr {
-    let mut bytes = [0_u8; 32];
-    let byte_vec = value.into_repr().to_bytes_be();
-    bytes.copy_from_slice(&byte_vec[..]);
-    let mut repr = <PosFr as ff::PrimeField>::Repr::default();
-    repr.read_be(&bytes[..])
-        .expect("read from correctly sized slice always succeeds");
-    PosFr::from_repr(repr).expect("value is always in range")
-}
-
-pub fn posfr_to_fr(value: PosFr) -> Fr {
-    let mut bytes = [0u8; 32];
-    value
-        .into_repr()
-        .write_be(&mut bytes[..])
-        .expect("write to correctly sized slice always succeeds");
-    Fr::from_be_bytes_mod_order(&bytes)
-}
-
-
-// Conversion Utilities between semaphore-rs Field and arkworks Fr
-
-use semaphore::Field;
-
-pub fn to_fr(el: &Field) -> Fr {
-    Fr::try_from(*el).unwrap()
-}
-
-pub fn to_field(el: &Fr) -> Field {
-    (*el).try_into().unwrap()
-}
-
-pub fn vec_to_fr(v: &[Field]) -> Vec<Fr> {
-    v.iter().map(|el| to_fr(el)).collect()
-}
-
-pub fn vec_to_field(v: &[Fr]) -> Vec<Field> {
-    v.iter().map(|el| to_field(el)).collect()
-}
-
-pub fn vec_fr_to_field(input: &[Fr]) -> Vec<Field> {
-    input.iter().map(|el| to_field(el)).collect()
-}
-
-pub fn vec_field_to_fr(input: &[Field]) -> Vec<Fr> {
-    input.iter().map(|el| to_fr(el)).collect()
-}
-
-pub fn str_to_field(input: String, radix: i32) -> Field {
-    assert!((radix == 10) || (radix == 16));
-
-    // We remove any quote present and we trim
-    let single_quote: char = '\"';
-    let input_clean = input.replace(single_quote, "");
-    let input_clean = input_clean.trim();
-
-    if radix == 10 {
-        Field::from_str(&format!(
-            "{:01$x}",
-            BigUint::from_str(input_clean).unwrap(),
-            64
-        ))
-        .unwrap()
+#[inline(always)]
+pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>, ConversionError> {
+    if input.len() < 8 {
+        return Err(ConversionError::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 input_clean = input_clean.replace("0x", "");
-        Field::from_str(&format!("{:0>64}", &input_clean)).unwrap()
+        if input.len() < 8 + nof_elem * 8 {
+            return Err(ConversionError::InsufficientData {
+                expected: 8 + nof_elem * 8,
+                actual: input.len(),
+            });
+        }
+        let elements: Vec<usize> = input[8..]
+            .chunks(8)
+            .take(nof_elem)
+            .map(|ch| usize::from_le_bytes(ch[0..8].try_into().unwrap()))
+            .collect();
+        Ok(elements)
     }
 }
 
-pub fn bytes_le_to_field(input: &[u8]) -> (Field, usize) {
-    let (fr_el, read) = bytes_le_to_fr(input);
-    (to_field(&fr_el), read)
+#[inline(always)]
+pub fn bytes_be_to_vec_usize(input: &[u8]) -> Result<Vec<usize>, ConversionError> {
+    if input.len() < 8 {
+        return Err(ConversionError::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(ConversionError::InsufficientData {
+                expected: 8 + nof_elem * 8,
+                actual: input.len(),
+            });
+        }
+        let elements: Vec<usize> = input[8..]
+            .chunks(8)
+            .take(nof_elem)
+            .map(|ch| usize::from_be_bytes(ch[0..8].try_into().unwrap()))
+            .collect();
+        Ok(elements)
+    }
 }
 
-pub fn bytes_be_to_field(input: &[u8]) -> (Field, usize) {
-    let (fr_el, read) = bytes_be_to_fr(input);
-    (to_field(&fr_el), read)
+/// 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_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
 }
 
-
-pub fn field_to_bytes_le(input: &Field) -> Vec<u8> {
-    fr_to_bytes_le(&to_fr(input))
+/// 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();
+    bytes[..input_bytes.len()].copy_from_slice(&input_bytes);
+    bytes
 }
 
-pub fn field_to_bytes_be(input: &Field) -> Vec<u8> {
-    fr_to_bytes_be(&to_fr(input))
+#[inline(always)] // using for test
+pub fn generate_input_buffer() -> Cursor<String> {
+    Cursor::new(json!({}).to_string())
 }
 
+#[derive(
+    Debug, Zeroize, ZeroizeOnDrop, Clone, PartialEq, CanonicalSerialize, CanonicalDeserialize,
+)]
+pub struct IdSecret(ark_bn254::Fr);
 
-pub fn vec_field_to_bytes_le(input: &[Field]) -> Vec<u8> {
-    vec_fr_to_bytes_le(&vec_field_to_fr(input))
+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]) -> (Self, usize) {
+        let el_size = fr_byte_size();
+        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
+        (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
+    }
 }
 
-pub fn vec_field_to_bytes_be(input: &[Field]) -> Vec<u8> {
-    vec_fr_to_bytes_be(&vec_field_to_fr(input))
+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;
 
-pub fn bytes_le_to_vec_field(input: &[u8]) -> (Vec<Field>, usize) {
-    let (vec_fr, read) = bytes_le_to_vec_fr(input);
-    (vec_fr_to_field(&vec_fr), read)
+    /// 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
+    }
 }
 
-pub fn bytes_be_to_vec_field(input: &[u8]) -> (Vec<Field>, usize) {
-    let (vec_fr, read) = bytes_be_to_vec_fr(input);
-    (vec_fr_to_field(&vec_fr), read)
+#[derive(Debug, Zeroize, ZeroizeOnDrop)]
+pub enum FrOrSecret {
+    IdSecret(IdSecret),
+    Fr(Fr),
 }
 
-// Arithmetic over Field elements (wrapped over arkworks algebra crate)
-
-pub fn add(a: &Field, b: &Field) -> Field {
-    to_field(&(to_fr(a) + to_fr(b)))
+impl From<Fr> for FrOrSecret {
+    fn from(value: Fr) -> Self {
+        FrOrSecret::Fr(value)
+    }
 }
 
-pub fn mul(a: &Field, b: &Field) -> Field {
-    to_field(&(to_fr(a) * to_fr(b)))
+impl From<IdSecret> for FrOrSecret {
+    fn from(value: IdSecret) -> Self {
+        FrOrSecret::IdSecret(value)
+    }
 }
-
-pub fn div(a: &Field, b: &Field) -> Field {
-    to_field(&(to_fr(a) / to_fr(b)))
-}
-
-pub fn inv(a: &Field) -> Field {
-    to_field(&(Fr::from(1) / to_fr(a)))
-}
-*/

rln/tests/poseidon_tree.rs

@@ -0,0 +1,151 @@
+////////////////////////////////////////////////////////////
+// Tests
+////////////////////////////////////////////////////////////
+
+#![cfg(not(feature = "stateless"))]
+
+#[cfg(test)]
+mod test {
+    use rln::hashers::{poseidon_hash, PoseidonHash};
+    use rln::{
+        circuit::{Fr, TEST_TREE_DEPTH},
+        poseidon_tree::PoseidonTree,
+    };
+    use utils::{FullMerkleTree, OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree};
+
+    #[test]
+    // 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(Fr::from).collect();
+
+        let mut tree_full = FullMerkleTree::<PoseidonHash>::default(TEST_TREE_DEPTH).unwrap();
+        let mut tree_opt = OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_DEPTH).unwrap();
+
+        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).expect("index should be set");
+            assert_eq!(proof.leaf_index(), i);
+
+            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");
+            assert_eq!(proof.leaf_index(), i);
+        }
+
+        // We check all roots are the same
+        let tree_full_root = tree_full.root();
+        let tree_opt_root = tree_opt.root();
+
+        assert_eq!(tree_full_root, tree_opt_root);
+    }
+
+    #[test]
+    fn test_subtree_root() {
+        const DEPTH: usize = 3;
+        const LEAVES_LEN: usize = 8;
+
+        let mut tree = PoseidonTree::default(DEPTH).unwrap();
+        let leaves: Vec<Fr> = (0..LEAVES_LEN).map(|s| Fr::from(s as i32)).collect();
+        let _ = tree.set_range(0, leaves.into_iter());
+
+        for i in 0..LEAVES_LEN {
+            // check leaves
+            assert_eq!(
+                tree.get(i).unwrap(),
+                tree.get_subtree_root(DEPTH, i).unwrap()
+            );
+            // check root
+            assert_eq!(tree.root(), tree.get_subtree_root(0, i).unwrap());
+        }
+
+        // check intermediate nodes
+        for n in (1..=DEPTH).rev() {
+            for i in (0..(1 << n)).step_by(2) {
+                let idx_l = i * (1 << (DEPTH - n));
+                let idx_r = (i + 1) * (1 << (DEPTH - n));
+                let idx_sr = idx_l;
+
+                let prev_l = tree.get_subtree_root(n, idx_l).unwrap();
+                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);
+            }
+        }
+    }
+
+    #[test]
+    fn test_get_empty_leaves_indices() {
+        let depth = 4;
+        let nof_leaves: usize = 1 << (depth - 1);
+
+        let mut tree = PoseidonTree::default(depth).unwrap();
+        let leaves: Vec<Fr> = (0..nof_leaves).map(|s| Fr::from(s as i32)).collect();
+
+        // check set_range
+        let _ = tree.set_range(0, leaves.clone().into_iter());
+        assert!(tree.get_empty_leaves_indices().is_empty());
+
+        let mut vec_idxs = Vec::new();
+        // check delete function
+        for i in 0..nof_leaves {
+            vec_idxs.push(i);
+            let _ = tree.delete(i);
+            assert_eq!(tree.get_empty_leaves_indices(), vec_idxs);
+        }
+        // check set function
+        for i in (0..nof_leaves).rev() {
+            vec_idxs.pop();
+            let _ = tree.set(i, leaves[i]);
+            assert_eq!(tree.get_empty_leaves_indices(), vec_idxs);
+        }
+
+        // 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(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]);
+
+        // check remove_indices inside override_range function
+        tree.override_range(0, [].into_iter(), [0, 1].into_iter())
+            .unwrap();
+        assert_eq!(tree.get_empty_leaves_indices(), vec![0, 1, 2, 3]);
+
+        // check set_range inside override_range function
+        tree.override_range(0, leaves_2.clone().into_iter(), [].into_iter())
+            .unwrap();
+        assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
+
+        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();
+        assert!(tree.get_empty_leaves_indices().is_empty());
+
+        // check if indexes for deletion are before indexes for overwriting
+        tree.override_range(4, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .unwrap();
+        // The result will be like this, because in the set_range function in pmtree
+        // the next_index value is increased not by the number of elements to insert,
+        // but by the union of indices for deleting and inserting.
+        assert_eq!(
+            tree.get_empty_leaves_indices(),
+            vec![0, 1, 2, 3, 8, 9, 10, 11]
+        );
+
+        // check if the indices for write and delete do not overlap completely
+        tree.override_range(2, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .unwrap();
+        // The result will be like this, because in the set_range function in pmtree
+        // the next_index value is increased not by the number of elements to insert,
+        // but by the union of indices for deleting and inserting.
+        // + we've already set to 6 and 7 in previous test
+        assert_eq!(tree.get_empty_leaves_indices(), vec![0, 1, 8, 9, 10, 11]);
+    }
+}

rln/tests/protocol.rs

@@ -0,0 +1,258 @@
+#![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_DEPTH};
+    use rln::hashers::{hash_to_field_le, poseidon_hash};
+    use rln::poseidon_tree::PoseidonTree;
+    use rln::protocol::{
+        deserialize_proof_values, deserialize_witness, generate_proof, keygen,
+        proof_values_from_witness, rln_witness_from_json, rln_witness_from_values,
+        rln_witness_to_json, seeded_keygen, serialize_proof_values, serialize_witness,
+        verify_proof, RLNWitnessInput,
+    };
+    use rln::utils::str_to_fr;
+    use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
+
+    type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
+
+    #[test]
+    // We test Merkle tree generation, proofs and verification
+    fn test_merkle_proof() {
+        let leaf_index = 3;
+
+        // generate identity
+        let identity_secret_hash = hash_to_field_le(b"test-merkle-proof");
+        let id_commitment = poseidon_hash(&[identity_secret_hash]);
+        let rate_commitment = poseidon_hash(&[id_commitment, 100.into()]);
+
+        // generate merkle tree
+        let default_leaf = Fr::from(0);
+        let mut tree = PoseidonTree::new(
+            TEST_TREE_DEPTH,
+            default_leaf,
+            ConfigOf::<PoseidonTree>::default(),
+        )
+        .unwrap();
+        tree.set(leaf_index, rate_commitment).unwrap();
+
+        // We check correct computation of the root
+        let root = tree.root();
+
+        assert_eq!(
+            root,
+            BigInt([
+                4939322235247991215,
+                5110804094006647505,
+                4427606543677101242,
+                910933464535675827
+            ])
+            .into()
+        );
+
+        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
+        let path_elements = merkle_proof.get_path_elements();
+        let identity_path_index = merkle_proof.get_path_index();
+
+        // We check correct computation of the path and indexes
+        let expected_path_elements: Vec<Fr> = [
+            "0x0000000000000000000000000000000000000000000000000000000000000000",
+            "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
+            "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
+            "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
+            "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
+            "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
+            "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
+            "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
+            "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
+            "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
+            "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
+            "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
+            "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
+            "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
+            "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
+            "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
+            "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
+            "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
+            "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
+            "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
+        ]
+        .map(|e| str_to_fr(e, 16).unwrap())
+        .to_vec();
+
+        let expected_identity_path_index: Vec<u8> =
+            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
+
+        assert_eq!(path_elements, expected_path_elements);
+        assert_eq!(identity_path_index, expected_identity_path_index);
+
+        // We check correct verification of the proof
+        assert!(tree.verify(&rate_commitment, &merkle_proof).unwrap());
+    }
+
+    fn get_test_witness() -> RLNWitnessInput {
+        let leaf_index = 3;
+        // Generate identity pair
+        let (identity_secret_hash, id_commitment) = keygen();
+        let user_message_limit = Fr::from(100);
+        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+
+        //// generate merkle tree
+        let default_leaf = Fr::from(0);
+        let mut tree = PoseidonTree::new(
+            TEST_TREE_DEPTH,
+            default_leaf,
+            ConfigOf::<PoseidonTree>::default(),
+        )
+        .unwrap();
+        tree.set(leaf_index, rate_commitment).unwrap();
+
+        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
+
+        let signal = b"hey hey";
+        let x = hash_to_field_le(signal);
+
+        // We set the remaining values to random ones
+        let epoch = hash_to_field_le(b"test-epoch");
+        let rln_identifier = hash_to_field_le(b"test-rln-identifier");
+        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+
+        rln_witness_from_values(
+            identity_secret_hash,
+            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);
+
+        // 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_values = proof_values_from_witness(&rln_witness_deser).unwrap();
+
+        // Let's verify the proof
+        let success = verify_proof(verification_key, &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);
+
+        // We test witness serialization
+        let ser = serialize_witness(&rln_witness).unwrap();
+        let (deser, _) = deserialize_witness(&ser).unwrap();
+        assert_eq!(rln_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);
+        assert_eq!(proof_values, deser);
+    }
+
+    #[test]
+    // Tests seeded keygen
+    // Note that hardcoded values are only valid for Bn254
+    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());
+
+        // We check against expected values
+        let expected_identity_secret_hash_seed_phrase = str_to_fr(
+            "0x20df38f3f00496f19fe7c6535492543b21798ed7cb91aebe4af8012db884eda3",
+            16,
+        )
+        .unwrap();
+        let expected_id_commitment_seed_phrase = str_to_fr(
+            "0x1223a78a5d66043a7f9863e14507dc80720a5602b2a894923e5b5147d5a9c325",
+            16,
+        )
+        .unwrap();
+
+        assert_eq!(
+            identity_secret_hash,
+            expected_identity_secret_hash_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);
+
+        // We check against expected values
+        let expected_identity_secret_hash_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        )
+        .unwrap();
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0xbf16d2b5c0d6f9d9d561e05bfca16a81b4b873bb063508fae360d8c74cef51f",
+            16,
+        )
+        .unwrap();
+
+        assert_eq!(
+            identity_secret_hash,
+            expected_identity_secret_hash_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());
+
+        assert_eq!(
+            identity_secret_hash,
+            expected_identity_secret_hash_seed_phrase
+        );
+        assert_eq!(id_commitment, expected_id_commitment_seed_phrase);
+    }
+}

rln/tests/public.rs

@@ -0,0 +1,384 @@
+#[cfg(test)]
+mod test {
+    #[cfg(not(feature = "stateless"))]
+    use {
+        ark_ff::BigInt,
+        rln::{
+            circuit::TEST_TREE_DEPTH,
+            protocol::compute_tree_root,
+            public::RLN,
+            utils::{
+                bytes_le_to_vec_fr, bytes_le_to_vec_u8, bytes_le_to_vec_usize, fr_to_bytes_le,
+                generate_input_buffer, IdSecret,
+            },
+        },
+        zeroize::Zeroize,
+    };
+
+    use ark_std::{rand::thread_rng, UniformRand};
+    use rand::Rng;
+    use rln::circuit::Fr;
+    use rln::hashers::{
+        hash_to_field_be, hash_to_field_le, poseidon_hash as utils_poseidon_hash, ROUND_PARAMS,
+    };
+    use rln::protocol::{
+        deserialize_identity_pair_be, deserialize_identity_pair_le, deserialize_identity_tuple_be,
+        deserialize_identity_tuple_le,
+    };
+    use rln::public::{
+        hash as public_hash, poseidon_hash as public_poseidon_hash, seeded_extended_key_gen,
+        seeded_key_gen,
+    };
+    use rln::utils::{
+        bytes_be_to_fr, bytes_le_to_fr, str_to_fr, vec_fr_to_bytes_be, vec_fr_to_bytes_le,
+    };
+    use std::io::Cursor;
+
+    #[test]
+    // This test is similar to the one in lib, but uses only public API
+    #[cfg(not(feature = "stateless"))]
+    fn test_merkle_proof() {
+        let leaf_index = 3;
+        let user_message_limit = 1;
+
+        let mut rln = RLN::new(TEST_TREE_DEPTH, generate_input_buffer()).unwrap();
+
+        // generate identity
+        let mut identity_secret_hash_ = hash_to_field_le(b"test-merkle-proof");
+        let identity_secret_hash = IdSecret::from(&mut identity_secret_hash_);
+
+        let mut to_hash = [*identity_secret_hash.clone()];
+        let id_commitment = utils_poseidon_hash(&to_hash);
+        to_hash[0].zeroize();
+
+        let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit.into()]);
+
+        // check that leaves indices is empty
+        let mut buffer = Cursor::new(Vec::<u8>::new());
+        rln.get_empty_leaves_indices(&mut buffer).unwrap();
+        let idxs = bytes_le_to_vec_usize(&buffer.into_inner()).unwrap();
+        assert!(idxs.is_empty());
+
+        // We pass rate_commitment as Read buffer to RLN's set_leaf
+        let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
+        rln.set_leaf(leaf_index, &mut buffer).unwrap();
+
+        // check that leaves before leaf_index is set to zero
+        let mut buffer = Cursor::new(Vec::<u8>::new());
+        rln.get_empty_leaves_indices(&mut buffer).unwrap();
+        let idxs = bytes_le_to_vec_usize(&buffer.into_inner()).unwrap();
+        assert_eq!(idxs, [0, 1, 2]);
+
+        // We check correct computation of the root
+        let mut buffer = Cursor::new(Vec::<u8>::new());
+        rln.get_root(&mut buffer).unwrap();
+        let (root, _) = bytes_le_to_fr(&buffer.into_inner());
+
+        assert_eq!(
+            root,
+            Fr::from(BigInt([
+                17110646155607829651,
+                5040045984242729823,
+                6965416728592533086,
+                2328960363755461975
+            ]))
+        );
+
+        // We check correct computation of merkle proof
+        let mut buffer = Cursor::new(Vec::<u8>::new());
+        rln.get_proof(leaf_index, &mut buffer).unwrap();
+
+        let buffer_inner = buffer.into_inner();
+        let (path_elements, read) = bytes_le_to_vec_fr(&buffer_inner).unwrap();
+        let (identity_path_index, _) = bytes_le_to_vec_u8(&buffer_inner[read..]).unwrap();
+
+        // We check correct computation of the path and indexes
+        let expected_path_elements: Vec<Fr> = [
+            "0x0000000000000000000000000000000000000000000000000000000000000000",
+            "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
+            "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
+            "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
+            "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
+            "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
+            "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
+            "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
+            "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
+            "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
+            "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
+            "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
+            "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
+            "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
+            "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
+            "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
+            "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
+            "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
+            "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
+            "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
+        ]
+        .map(|e| str_to_fr(e, 16).unwrap())
+        .to_vec();
+
+        let expected_identity_path_index: Vec<u8> =
+            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
+
+        assert_eq!(path_elements, expected_path_elements);
+        assert_eq!(identity_path_index, expected_identity_path_index);
+
+        // check subtree root computation for leaf 0 for all corresponding node until the root
+        let l_idx = 0;
+        for n in (1..=TEST_TREE_DEPTH).rev() {
+            let idx_l = l_idx * (1 << (TEST_TREE_DEPTH - n));
+            let idx_r = (l_idx + 1) * (1 << (TEST_TREE_DEPTH - n));
+            let idx_sr = idx_l;
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n, idx_l, &mut buffer).unwrap();
+            let (prev_l, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n, idx_r, &mut buffer).unwrap();
+            let (prev_r, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n - 1, idx_sr, &mut buffer).unwrap();
+            let (subroot, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let res = utils_poseidon_hash(&[prev_l, prev_r]);
+            assert_eq!(res, subroot);
+        }
+
+        // We double check that the proof computed from public API is correct
+        let root_from_proof = compute_tree_root(
+            &identity_secret_hash,
+            &user_message_limit.into(),
+            &path_elements,
+            &identity_path_index,
+        );
+
+        assert_eq!(root, root_from_proof);
+    }
+
+    #[test]
+    fn test_seeded_keygen() {
+        let seed_bytes: &[u8] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+
+        let mut input_buffer = Cursor::new(&seed_bytes);
+        let mut output_buffer = Cursor::new(Vec::<u8>::new());
+
+        seeded_key_gen(&mut input_buffer, &mut output_buffer, true).unwrap();
+        let serialized_output = output_buffer.into_inner();
+
+        let (identity_secret_hash, id_commitment) = deserialize_identity_pair_le(serialized_output);
+
+        // We check against expected values
+        let expected_identity_secret_hash_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        )
+        .unwrap();
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0xbf16d2b5c0d6f9d9d561e05bfca16a81b4b873bb063508fae360d8c74cef51f",
+            16,
+        )
+        .unwrap();
+
+        assert_eq!(
+            identity_secret_hash,
+            expected_identity_secret_hash_seed_bytes
+        );
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes);
+    }
+
+    #[test]
+    fn test_seeded_keygen_big_endian() {
+        let seed_bytes: &[u8] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+
+        let mut input_buffer = Cursor::new(&seed_bytes);
+        let mut output_buffer = Cursor::new(Vec::<u8>::new());
+
+        seeded_key_gen(&mut input_buffer, &mut output_buffer, false).unwrap();
+        let serialized_output = output_buffer.into_inner();
+
+        let (identity_secret_hash, id_commitment) = deserialize_identity_pair_be(serialized_output);
+
+        // We check against expected values
+        let expected_identity_secret_hash_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        )
+        .unwrap();
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0xbf16d2b5c0d6f9d9d561e05bfca16a81b4b873bb063508fae360d8c74cef51f",
+            16,
+        )
+        .unwrap();
+
+        assert_eq!(
+            identity_secret_hash,
+            expected_identity_secret_hash_seed_bytes
+        );
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes);
+    }
+
+    #[test]
+    fn test_seeded_extended_keygen() {
+        let seed_bytes: &[u8] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+
+        let mut input_buffer = Cursor::new(&seed_bytes);
+        let mut output_buffer = Cursor::new(Vec::<u8>::new());
+
+        seeded_extended_key_gen(&mut input_buffer, &mut output_buffer, true).unwrap();
+        let serialized_output = output_buffer.into_inner();
+
+        let (identity_trapdoor, identity_nullifier, identity_secret_hash, id_commitment) =
+            deserialize_identity_tuple_le(serialized_output);
+
+        // 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_hash_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_hash,
+            expected_identity_secret_hash_seed_bytes
+        );
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes);
+    }
+
+    #[test]
+    fn test_seeded_extended_keygen_big_endian() {
+        let seed_bytes: &[u8] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+
+        let mut input_buffer = Cursor::new(&seed_bytes);
+        let mut output_buffer = Cursor::new(Vec::<u8>::new());
+
+        seeded_extended_key_gen(&mut input_buffer, &mut output_buffer, false).unwrap();
+        let serialized_output = output_buffer.into_inner();
+
+        let (identity_trapdoor, identity_nullifier, identity_secret_hash, id_commitment) =
+            deserialize_identity_tuple_be(serialized_output);
+
+        // 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_hash_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_hash,
+            expected_identity_secret_hash_seed_bytes
+        );
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes);
+    }
+
+    #[test]
+    fn test_hash_to_field() {
+        let mut rng = thread_rng();
+        let signal: [u8; 32] = rng.gen();
+
+        let mut input_buffer = Cursor::new(&signal);
+        let mut output_buffer = Cursor::new(Vec::<u8>::new());
+
+        public_hash(&mut input_buffer, &mut output_buffer, true).unwrap();
+        let serialized_hash = output_buffer.into_inner();
+        let (hash1, _) = bytes_le_to_fr(&serialized_hash);
+
+        let hash2 = hash_to_field_le(&signal);
+
+        assert_eq!(hash1, hash2);
+    }
+
+    #[test]
+    fn test_hash_to_field_big_endian() {
+        let mut rng = thread_rng();
+        let signal: [u8; 32] = rng.gen();
+
+        let mut input_buffer = Cursor::new(&signal);
+        let mut output_buffer = Cursor::new(Vec::<u8>::new());
+
+        public_hash(&mut input_buffer, &mut output_buffer, false).unwrap();
+        let serialized_hash = output_buffer.into_inner();
+        let (hash1, _) = bytes_be_to_fr(&serialized_hash);
+
+        let hash2 = hash_to_field_be(&signal);
+
+        assert_eq!(hash1, hash2);
+    }
+
+    #[test]
+    fn test_poseidon_hash() {
+        let mut rng = thread_rng();
+        let number_of_inputs = rng.gen_range(1..ROUND_PARAMS.len());
+        let mut inputs = Vec::with_capacity(number_of_inputs);
+        for _ in 0..number_of_inputs {
+            inputs.push(Fr::rand(&mut rng));
+        }
+        let expected_hash = utils_poseidon_hash(&inputs);
+
+        let mut input_buffer = Cursor::new(vec_fr_to_bytes_le(&inputs));
+        let mut output_buffer = Cursor::new(Vec::<u8>::new());
+
+        public_poseidon_hash(&mut input_buffer, &mut output_buffer, true).unwrap();
+        let serialized_hash = output_buffer.into_inner();
+        let (hash, _) = bytes_le_to_fr(&serialized_hash);
+
+        assert_eq!(hash, expected_hash);
+    }
+
+    #[test]
+    fn test_poseidon_hash_big_endian() {
+        let mut rng = thread_rng();
+        let number_of_inputs = rng.gen_range(1..ROUND_PARAMS.len());
+        let mut inputs = Vec::with_capacity(number_of_inputs);
+        for _ in 0..number_of_inputs {
+            inputs.push(Fr::rand(&mut rng));
+        }
+        let expected_hash = utils_poseidon_hash(&inputs);
+
+        let mut input_buffer = Cursor::new(vec_fr_to_bytes_be(&inputs));
+        let mut output_buffer = Cursor::new(Vec::<u8>::new());
+
+        public_poseidon_hash(&mut input_buffer, &mut output_buffer, false).unwrap();
+        let serialized_hash = output_buffer.into_inner();
+        let (hash, _) = bytes_be_to_fr(&serialized_hash);
+
+        assert_eq!(hash, expected_hash);
+    }
+}

rln/tests/utils.rs

@@ -0,0 +1,411 @@
+#[cfg(test)]
+mod test {
+    use 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,
+        vec_fr_to_bytes_be, vec_fr_to_bytes_le, vec_u8_to_bytes_be, vec_u8_to_bytes_le,
+    };
+
+    use ark_std::{rand::thread_rng, UniformRand};
+    use rln::circuit::Fr;
+
+    #[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);
+            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);
+            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);
+            let (reconstructed_be, _) = bytes_be_to_fr(&be_bytes);
+            assert_eq!(fr, reconstructed_le);
+            assert_eq!(fr, reconstructed_be);
+        }
+    }
+
+    #[test]
+    fn test_error_handling() {
+        // Test with valid length but insufficient data
+        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);
+    }
+}

semaphore/Cargo.toml

@@ -1,49 +0,0 @@
-[package]
-name = "semaphore-wrapper"
-version = "0.1.0"
-edition = "2021"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[features]
-default = []
-dylib = [ "wasmer/dylib", "wasmer-engine-dylib", "wasmer-compiler-cranelift" ]
-
-[dependencies]
-ark-bn254 = { version = "0.3.0" }
-ark-circom = { git = "https://github.com/gakonst/ark-circom", features=["circom-2"] }
-ark-ec = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-ark-relations = { version = "0.3.0", default-features = false }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-color-eyre = "0.5"
-num-bigint = { version = "0.4", default-features = false, features = ["rand"] }
-once_cell = "1.8"
-primitive-types = "0.11.1"
-rand = "0.8.4"
-semaphore = { git = "https://github.com/worldcoin/semaphore-rs", rev = "d462a43"}
-serde = "1.0"
-thiserror = "1.0.0"
-wasmer = { version = "2.0" }
-
-[dev-dependencies]
-rand_chacha = "0.3.1"
-serde_json = "1.0.79"
-
-[build-dependencies]
-color-eyre = "0.5"
-wasmer = { version = "2.0" }
-wasmer-engine-dylib = { version = "2.2.1", optional = true }
-wasmer-compiler-cranelift = { version = "2.2.1", optional = true }
-
-[profile.release]
-codegen-units = 1
-lto = true
-panic = "abort"
-opt-level = 3
-
-# 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.
-[profile.dev.package."*"]
-opt-level = 3

semaphore/README.md

@@ -1,10 +0,0 @@
-# Semaphore example package
-
-This is basically a wrapper around/copy of
-https://github.com/worldcoin/semaphore-rs to illustrate how e.g. RLN package
-can be structured like.
-
-Goal is also to provide a basic FFI around protocol.rs, which is currently not
-in scope for that project.
-
-See that project for more information.