chore(rln): update dependencies and refactor code for compatibility (#291)

While publishing the release on crate io it turned out that we can't use
libraries without a version as it was for arc-circom.

During the upgrade to the new version it was also discovered that it is
possible to speed up input preparation for witness calculator by 4 times
by switching from bigint to Fr:


![image](https://github.com/user-attachments/assets/53962387-308b-4aae-8af2-dbd0d3f62369)

it was also checked that it is also possible to use iden3 as a
sub-module instead of copying code, but benchmarks showed that the new
iden3 version with u256 calculations and subsequent conversion of the
result to Fr is slower than the current implementation:


![image](https://github.com/user-attachments/assets/f950f089-b66a-4a13-a86f-f391caf32b4f)

----

- Updated dependencies to their latest versions, including ark-ff,
ark-bn254, ark-std, and others to 0.5.0.
- Refactored circuit and iden3calc modules to use Fr instead of BigInt
for better type consistency.
- Improved utility functions for type conversions between Fr and U256.
- Adjusted Cargo.toml files for rln and utils to reflect new dependency
versions and features.
- Enhanced documentation and comments for clarity on changes made.

This update ensures compatibility with the latest versions of the Ark
framework and improves overall code quality.

.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

@@ -5,7 +5,6 @@ on:
     paths-ignore:
       - "**.md"
       - "!.github/workflows/*.yml"
-      - "!rln-wasm/**"
       - "!rln/src/**"
       - "!rln/resources/**"
       - "!utils/src/**"
@@ -13,7 +12,6 @@ on:
     paths-ignore:
       - "**.md"
       - "!.github/workflows/*.yml"
-      - "!rln-wasm/**"
       - "!rln/src/**"
       - "!rln/resources/**"
       - "!utils/src/**"
@@ -21,11 +19,11 @@ on:
 name: Tests
 
 jobs:
-  test:
+  utils-test:
     strategy:
       matrix:
-        platform: [ubuntu-latest, macos-latest]
-        crate: [rln, utils]
+        platform: [ ubuntu-latest, macos-latest ]
+        crate: [ utils ]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
@@ -47,16 +45,19 @@ jobs:
           cargo make test --release
         working-directory: ${{ matrix.crate }}
 
-  rln-wasm:
+  rln-test:
     strategy:
       matrix:
-        platform: [ubuntu-latest, macos-latest]
+        platform: [ ubuntu-latest, macos-latest ]
+        crate: [ rln ]
+        feature: [ "default", "arkzkey", "stateless" ]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: test - rln-wasm - ${{ matrix.platform }}
+    name: test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
     steps:
-      - uses: actions/checkout@v3
+      - name: Checkout sources
+        uses: actions/checkout@v3
       - name: Install stable toolchain
         uses: actions-rs/toolchain@v1
         with:
@@ -64,21 +65,23 @@ jobs:
           toolchain: stable
           override: true
       - uses: Swatinem/rust-cache@v2
-      - name: Install Dependencies
+      - name: Install dependencies
         run: make installdeps
-      - name: Install wasm-pack
-        uses: jetli/wasm-pack-action@v0.3.0
-      - run: cargo make build
-        working-directory: rln-wasm
-      - run: cargo make test --release
-        working-directory: rln-wasm
+      - name: cargo-make test
+        run: |
+          if [ ${{ matrix.feature }} == default ]; then
+            cargo make test --release
+          else
+            cargo make test_${{ matrix.feature }} --release
+          fi
+        working-directory: ${{ matrix.crate }}
 
   lint:
     strategy:
       matrix:
         # we run lint tests only on ubuntu
-        platform: [ubuntu-latest]
-        crate: [rln, utils]
+        platform: [ ubuntu-latest ]
+        crate: [ rln, utils ]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
@@ -105,17 +108,15 @@ jobs:
         run: |
           cargo clippy --release -- -D warnings
         working-directory: ${{ matrix.crate }}
-        # We skip clippy on rln-wasm, since wasm target is managed by cargo make
-        # Currently not treating warnings as error, too noisy
-        # -- -D warnings
-  benchmark:
+
+  benchmark-utils:
     # run only in pull requests
     if: github.event_name == 'pull_request'
     strategy:
       matrix:
         # we run benchmark tests only on ubuntu
-        platform: [ubuntu-latest]
-        crate: [rln, utils]
+        platform: [ ubuntu-latest ]
+        crate: [ utils ]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
@@ -128,3 +129,26 @@ jobs:
         with:
           branchName: ${{ github.base_ref }}
           cwd: ${{ matrix.crate }}
+
+  benchmark-rln:
+    # run only in pull requests
+    if: github.event_name == 'pull_request'
+    strategy:
+      matrix:
+        # we run benchmark tests only on ubuntu
+        platform: [ ubuntu-latest ]
+        crate: [ rln ]
+        feature: [ "default", "arkzkey" ]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: benchmark - ${{ matrix.platform }} - ${{ matrix.crate }} - ${{ matrix.feature }}
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v3
+      - 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

@@ -8,11 +8,14 @@ jobs:
   linux:
     strategy:
       matrix:
-        feature: ["default", "arkzkey"]
+        feature: [ "default", "arkzkey", "stateless" ]
         target:
           - x86_64-unknown-linux-gnu
           - aarch64-unknown-linux-gnu
-          - i686-unknown-linux-gnu
+          # - i686-unknown-linux-gnu
+        include:
+          - feature: stateless
+            cargo_args: --exclude rln-cli
     name: Linux build
     runs-on: ubuntu-latest
     steps:
@@ -30,13 +33,13 @@ jobs:
         run: make installdeps
       - name: cross build
         run: |
-          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace --exclude rln-wasm
+          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace ${{ matrix.cargo_args }}
           mkdir release
           cp target/${{ matrix.target }}/release/librln* release/
           tar -czvf ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz release/
 
       - name: Upload archive artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.target }}-${{ matrix.feature }}-archive
           path: ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz
@@ -47,10 +50,13 @@ jobs:
     runs-on: macos-latest
     strategy:
       matrix:
-        feature: ["default", "arkzkey"]
+        feature: [ "default", "arkzkey", "stateless" ]
         target:
           - x86_64-apple-darwin
           - aarch64-apple-darwin
+        include:
+          - feature: stateless
+            cargo_args: --exclude rln-cli
     steps:
       - name: Checkout sources
         uses: actions/checkout@v3
@@ -66,53 +72,21 @@ jobs:
         run: make installdeps
       - name: cross build
         run: |
-          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace --exclude rln-wasm
+          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace ${{ matrix.cargo_args }}
           mkdir release
           cp target/${{ matrix.target }}/release/librln* release/
           tar -czvf ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz release/
 
       - name: Upload archive artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.target }}-${{ matrix.feature }}-archive
           path: ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz
           retention-days: 2
 
-  browser-rln-wasm:
-    name: Browser build (RLN WASM)
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout sources
-        uses: actions/checkout@v3
-      - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-      - uses: Swatinem/rust-cache@v2
-      - name: Install dependencies
-        run: make installdeps
-      - name: Install wasm-pack
-        uses: jetli/wasm-pack-action@v0.3.0
-      - name: cross make build
-        run: |
-          cross make build
-          mkdir release
-          cp pkg/** release/
-          tar -czvf browser-rln-wasm.tar.gz release/
-        working-directory: rln-wasm
-
-      - name: Upload archive artifact
-        uses: actions/upload-artifact@v2
-        with:
-          name: browser-rln-wasm-archive
-          path: rln-wasm/browser-rln-wasm.tar.gz
-          retention-days: 2
-
   prepare-prerelease:
     name: Prepare pre-release
-    needs: [linux, macos, browser-rln-wasm]
+    needs: [ linux, macos ]
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
@@ -120,7 +94,7 @@ jobs:
         with:
           ref: master
       - name: Download artifacts
-        uses: actions/download-artifact@v2
+        uses: actions/download-artifact@v4
 
       - name: Delete tag
         uses: dev-drprasad/delete-tag-and-release@v0.2.1
@@ -143,7 +117,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Delete artifacts
-        uses: geekyeggo/delete-artifact@v1
+        uses: geekyeggo/delete-artifact@v5
         with:
           failOnError: false
           name: |

.gitignore

@@ -3,6 +3,7 @@
 *.log
 tmp/
 rln/pmtree_db
+rln-cli/database
 
 # Generated by Cargo
 # will have compiled files and executables

Cargo.toml

@@ -1,5 +1,5 @@
 [workspace]
-members = ["rln", "rln-cli", "rln-wasm", "utils"]
+members = ["rln", "rln-cli", "utils"]
 default-members = ["rln", "rln-cli", "utils"]
 resolver = "2"
 
@@ -8,7 +8,3 @@ resolver = "2"
 # while having neglible impact on incremental build times.
 [profile.dev.package."*"]
 opt-level = 3
-
-[profile.release.package."rln-wasm"]
-# Tell `rustc` to optimize for small code size.
-opt-level = "s"

Makefile

@@ -16,13 +16,14 @@ ifeq ($(shell uname),Darwin)
 # commented due to https://github.com/orgs/Homebrew/discussions/4612
 # @brew update
 	@brew install cmake ninja
+	@git -C "wabt" pull || git clone --recursive https://github.com/WebAssembly/wabt.git "wabt"
+	@cd wabt && mkdir -p build && make
 else ifeq ($(shell uname),Linux)
 	@sudo apt-get update
 	@sudo apt-get install -y cmake ninja-build
-endif
 	@git -C "wabt" pull || git clone --recursive https://github.com/WebAssembly/wabt.git "wabt"
 	@cd wabt && mkdir -p build && cd build && cmake .. -GNinja && ninja && sudo ninja install
-	@which wasm-pack || cargo install wasm-pack
+endif
 	# nvm already checks if it's installed, and no-ops if it is
 	@curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.7/install.sh | bash
 	@. ${HOME}/.nvm/nvm.sh && nvm install 18.20.2 && nvm use 18.20.2;

README.md

@@ -1,45 +1,81 @@
 # 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
 
-## Acknowledgements
+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.
 
-- Uses [ark-circom](https://github.com/gakonst/ark-circom), Rust wrapper around Circom.
+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.
 
-- Inspired by Applied ZKP group work, e.g. [zk-kit](https://github.com/appliedzkp/zk-kit).
+## Features
 
-- [RLN library](https://github.com/kilic/rln) written in Rust based on Bellman.
+- **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
 
-- [semaphore-rs](https://github.com/worldcoin/semaphore-rs) written in Rust based on ark-circom.
+## Architecture
 
-## Users
-
-Zerokit is used by -
-
-- [nwaku](https://github.com/waku-org/nwaku)
-- [js-rln](https://github.com/waku-org/js-rln)
+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
 
-To install missing dependencies, run the following commands from the root folder
+> [!IMPORTANT]
+> For WASM support or x32 architecture builds, use version `0.6.1`. The current version has dependency issues for these platforms. WASM support will return in a future release.
+
+### Install Dependencies
 
 ```bash
 make installdeps
 ```
 
-To build and test all crates, run the following commands from the root folder
+### Build and Test All Crates
 
 ```bash
 make build
 make test
 ```
 
-## Release assets
+## Release Assets
 
-We use [`cross-rs`](https://github.com/cross-rs/cross) to cross-compile and generate release assets for rln.
+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
+
+- 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.
+
+> [!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.
+
+## Documentation
+
+For detailed documentation on each module:
+
+```bash
+cargo doc --open
+```

rln-cli/Cargo.toml

@@ -1,13 +1,26 @@
 [package]
 name = "rln-cli"
-version = "0.3.0"
+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" }
-clap = { version = "4.2.7", features = ["cargo", "derive", "env"]}
-clap_derive = { version = "=4.2.0" }
-color-eyre = "=0.6.2"
-# serialization
-serde_json = "1.0.48"
-serde = { version = "1.0.130", features = ["derive"] }
+rln = { path = "../rln", default-features = true, features = ["pmtree-ft"] }
+zerokit_utils = { path = "../utils" }
+clap = { version = "4.5.29", features = ["cargo", "derive", "env"] }
+clap_derive = { version = "4.5.28" }
+color-eyre = "0.6.2"
+serde_json = "1.0.138"
+serde = { version = "1.0.217", features = ["derive"] }
+
+[features]
+arkzkey = ["rln/arkzkey"]
+stateless = ["rln/stateless"]

rln-cli/Makefile.toml

@@ -0,0 +1,8 @@
+[tasks.build]
+command = "cargo"
+args = ["build", "--release"]
+
+[tasks.test]
+command = "cargo"
+args = ["test", "--release"]
+

rln-cli/README.md

@@ -0,0 +1,170 @@
+# Zerokit RLN-CLI
+
+The Zerokit RLN-CLI provides a command-line interface for interacting with the public API of the [Zerokit RLN Module](../rln/README.md).
+
+It also contain:
+
++ [Relay Example](#relay-example) to demonstrate the use of the RLN module for spam prevention.
++ [Stateless Example](#stateless-example) to demonstrate the use of the RLN module for stateless features.
+
+## Configuration
+
+The CLI can be configured using a JSON configuration file (see the [example](example.config.json)).
+
+You can specify the configuration file path using the `RLN_CONFIG_PATH` environment variable:
+
+```bash
+export RLN_CONFIG_PATH=example.config.json
+```
+
+Alternatively, you can provide the configuration file path as an argument for each command:
+
+```bash
+RLN_CONFIG_PATH=example.config.json cargo run -- <SUBCOMMAND> [OPTIONS]
+```
+
+If the configuration file is empty, default settings will be used, but the tree data folder will be temporary and not saved to the preconfigured path.
+
+We recommend using the example config, as all commands (except `new` and `create-with-params`) require an initialized RLN instance.
+
+## Feature Flags
+
+The CLI supports optional features. To enable the **arkzkey** feature, run:
+
+```bash
+cargo run --features arkzkey -- <SUBCOMMAND> [OPTIONS]
+```
+
+For more details, refer to the [Zerokit RLN Module](../rln/README.md) documentation.
+
+## 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
+```
+
+or with the **arkzkey** feature flag:
+
+```bash
+cargo run --example relay --features arkzkey
+```
+
+You can also change **MESSAGE_LIMIT** and **TREEE_HEIGHT** in the [relay.rs](src/examples/relay.rs) file to see how the RLN instance behaves with different parameters.
+
+The customize **TREEE_HEIGHT** constant differs from the default value of `20` should follow [Custom Circuit Compilation](../rln/README.md#advanced-custom-circuit-compilation) instructions.
+
+## 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 --features stateless
+```
+
+or with the **arkzkey** feature flag:
+
+```bash
+cargo run --example stateless --features stateless,arkzkey
+```
+
+## CLI Commands
+
+### Instance Management
+
+To initialize a new RLN instance:
+
+```bash
+cargo run new --tree-height <HEIGHT>
+```
+
+To initialize an RLN instance with custom parameters:
+
+```bash
+cargo run new-with-params --resources-path <PATH> --tree-height <HEIGHT>
+```
+
+To update the Merkle tree height:
+
+```bash
+cargo run set-tree --tree-height <HEIGHT>
+```
+
+### Leaf Operations
+
+To set a single leaf:
+
+```bash
+cargo run set-leaf --index <INDEX> --input <INPUT_PATH>
+```
+
+To set multiple leaves:
+
+```bash
+cargo run set-multiple-leaves --index <START_INDEX> --input <INPUT_PATH>
+```
+
+To reset multiple leaves:
+
+```bash
+cargo run reset-multiple-leaves --input <INPUT_PATH>
+```
+
+To set the next available leaf:
+
+```bash
+cargo run set-next-leaf --input <INPUT_PATH>
+```
+
+To delete a specific leaf:
+
+```bash
+cargo run delete-leaf --index <INDEX>
+```
+
+### Proof Operations
+
+To generate a proof:
+
+```bash
+cargo run prove --input <INPUT_PATH>
+```
+
+To generate an RLN proof:
+
+```bash
+cargo run generate-proof --input <INPUT_PATH>
+```
+
+To verify a proof:
+
+```bash
+cargo run verify --input <PROOF_PATH>
+```
+
+To verify a proof with multiple Merkle roots:
+
+```bash
+cargo run verify-with-roots --input <INPUT_PATH> --roots <ROOTS_PATH>
+```
+
+### Tree Information
+
+To retrieve the current Merkle root:
+
+```bash
+cargo run get-root
+```
+
+To obtain a Merkle proof for a specific index:
+
+```bash
+cargo run get-proof --index <INDEX>
+```

rln-cli/example.config.json

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

rln-cli/src/commands.rs

@@ -1,49 +1,51 @@
 use std::path::PathBuf;
 
 use clap::Subcommand;
+use rln::circuit::TEST_TREE_HEIGHT;
 
 #[derive(Subcommand)]
 pub(crate) enum Commands {
     New {
+        #[arg(short, long, default_value_t = TEST_TREE_HEIGHT)]
         tree_height: usize,
-        /// Sets a custom config file
-        #[arg(short, long)]
-        config: PathBuf,
     },
     NewWithParams {
+        #[arg(short, long, default_value_t = TEST_TREE_HEIGHT)]
         tree_height: usize,
-        /// Sets a custom config file
-        #[arg(short, long)]
-        config: PathBuf,
-        #[arg(short, long)]
-        tree_config_input: PathBuf,
+        #[arg(short, long, default_value = "../rln/resources/tree_height_20")]
+        resources_path: PathBuf,
     },
     SetTree {
+        #[arg(short, long, default_value_t = TEST_TREE_HEIGHT)]
         tree_height: usize,
     },
     SetLeaf {
+        #[arg(short, long)]
         index: usize,
         #[arg(short, long)]
-        file: PathBuf,
+        input: PathBuf,
     },
     SetMultipleLeaves {
+        #[arg(short, long)]
         index: usize,
         #[arg(short, long)]
-        file: PathBuf,
+        input: PathBuf,
     },
     ResetMultipleLeaves {
         #[arg(short, long)]
-        file: PathBuf,
+        input: PathBuf,
     },
     SetNextLeaf {
         #[arg(short, long)]
-        file: PathBuf,
+        input: PathBuf,
     },
     DeleteLeaf {
+        #[arg(short, long)]
         index: usize,
     },
     GetRoot,
     GetProof {
+        #[arg(short, long)]
         index: usize,
     },
     Prove {
@@ -52,7 +54,7 @@ pub(crate) enum Commands {
     },
     Verify {
         #[arg(short, long)]
-        file: PathBuf,
+        input: PathBuf,
     },
     GenerateProof {
         #[arg(short, long)]

rln-cli/src/config.rs

@@ -1,8 +1,10 @@
-use color_eyre::Result;
-use serde::{Deserialize, Serialize};
 use std::{fs::File, io::Read, path::PathBuf};
 
-pub const RLN_STATE_PATH: &str = "RLN_STATE_PATH";
+use color_eyre::Result;
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+pub const RLN_CONFIG_PATH: &str = "RLN_CONFIG_PATH";
 
 #[derive(Default, Serialize, Deserialize)]
 pub(crate) struct Config {
@@ -11,19 +13,26 @@ pub(crate) struct Config {
 
 #[derive(Default, Serialize, Deserialize)]
 pub(crate) struct InnerConfig {
-    pub file: PathBuf,
     pub tree_height: usize,
+    pub tree_config: Value,
 }
 
 impl Config {
     pub(crate) fn load_config() -> Result<Config> {
-        let path = PathBuf::from(std::env::var(RLN_STATE_PATH)?);
+        match std::env::var(RLN_CONFIG_PATH) {
+            Ok(env) => {
+                let path = PathBuf::from(env);
+                let mut file = File::open(path)?;
+                let mut contents = String::new();
+                file.read_to_string(&mut contents)?;
+                let inner: InnerConfig = serde_json::from_str(&contents)?;
+                Ok(Config { inner: Some(inner) })
+            }
+            Err(_) => Ok(Config::default()),
+        }
+    }
 
-        let mut file = File::open(path)?;
-
-        let mut contents = String::new();
-        file.read_to_string(&mut contents)?;
-        let state: Config = serde_json::from_str(&contents)?;
-        Ok(state)
+    pub(crate) fn as_bytes(&self) -> Vec<u8> {
+        serde_json::to_string(&self.inner).unwrap().into_bytes()
     }
 }

rln-cli/src/examples/relay.rs

@@ -0,0 +1,317 @@
+use std::{
+    collections::HashMap,
+    fs::File,
+    io::{stdin, stdout, Cursor, Read, Write},
+    path::{Path, PathBuf},
+};
+
+use clap::{Parser, Subcommand};
+use color_eyre::{eyre::eyre, Result};
+use rln::{
+    circuit::Fr,
+    hashers::{hash_to_field, poseidon_hash},
+    protocol::{keygen, prepare_prove_input, prepare_verify_input},
+    public::RLN,
+    utils::{bytes_le_to_fr, fr_to_bytes_le, generate_input_buffer},
+};
+
+const MESSAGE_LIMIT: u32 = 1;
+
+const TREEE_HEIGHT: usize = 20;
+
+#[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: Fr,
+    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_height_{TREEE_HEIGHT}").into();
+        #[cfg(feature = "arkzkey")]
+        let filenames = ["rln_final.arkzkey", "graph.bin"];
+        #[cfg(not(feature = "arkzkey"))]
+        let filenames = ["rln_final.zkey", "graph.bin"];
+        for filename in filenames {
+            let fullpath = resources_path.join(Path::new(filename));
+            let mut file = File::open(&fullpath)?;
+            let metadata = std::fs::metadata(&fullpath)?;
+            let mut output_buffer = vec![0; metadata.len() as usize];
+            file.read_exact(&mut output_buffer)?;
+            resources.push(output_buffer);
+        }
+        let rln = RLN::new_with_params(
+            TREEE_HEIGHT,
+            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^{TREEE_HEIGHT}");
+            }
+        };
+
+        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,
+            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(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, _) = bytes_le_to_fr(&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;
+                    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 {leaked_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(b"epoch");
+    let rln_identifier = hash_to_field(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 +1,313 @@
+#![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_HEIGHT},
+    hashers::{hash_to_field, poseidon_hash},
+    poseidon_tree::PoseidonTree,
+    protocol::{keygen, prepare_verify_input, rln_witness_from_values, serialize_witness},
+    public::RLN,
+    utils::{bytes_le_to_fr, fr_to_bytes_le},
+};
+use zerokit_utils::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: Fr,
+    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: PoseidonTree,
+    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 = PoseidonTree::new(
+            TEST_TREE_HEIGHT,
+            default_leaf,
+            ConfigOf::<PoseidonTree>::default(),
+        )?;
+
+        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 rln_witness = rln_witness_from_values(
+            identity.identity_secret_hash,
+            &merkle_proof,
+            hash_to_field(signal.as_bytes()),
+            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 root_serialized = fr_to_bytes_le(&root);
+        let mut root_buffer = Cursor::new(root_serialized);
+
+        match self
+            .rln
+            .verify_with_roots(&mut input_buffer, &mut root_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, _) = bytes_le_to_fr(&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;
+                    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);
+                        println!("User index {user_index} has been SLASHED");
+                        Ok(())
+                    }
+                } else {
+                    Err(eyre!(
+                        "user identity secret hash {leaked_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(b"epoch");
+    let rln_identifier = hash_to_field(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

@@ -1,9 +1,18 @@
-use std::{fs::File, io::Read, path::Path};
+use std::{
+    fs::File,
+    io::{Cursor, Read},
+    path::Path,
+};
 
 use clap::Parser;
-use color_eyre::{Report, Result};
+use color_eyre::{eyre::Report, Result};
 use commands::Commands;
-use rln::public::RLN;
+use config::{Config, InnerConfig};
+use rln::{
+    public::RLN,
+    utils::{bytes_le_to_fr, bytes_le_to_vec_fr},
+};
+use serde_json::json;
 use state::State;
 
 mod commands;
@@ -20,78 +29,97 @@ struct Cli {
 fn main() -> Result<()> {
     let cli = Cli::parse();
 
-    let mut state = State::load_state()?;
+    let mut state = match &cli.command {
+        Some(Commands::New { .. }) | Some(Commands::NewWithParams { .. }) => State::default(),
+        _ => State::load_state()?,
+    };
 
-    match &cli.command {
-        Some(Commands::New {
-            tree_height,
-            config,
-        }) => {
-            let resources = File::open(&config)?;
-            state.rln = Some(RLN::new(*tree_height, resources)?);
+    match cli.command {
+        Some(Commands::New { tree_height }) => {
+            let config = Config::load_config()?;
+            state.rln = if let Some(InnerConfig { tree_height, .. }) = config.inner {
+                println!("Initializing RLN with custom config");
+                Some(RLN::new(tree_height, Cursor::new(config.as_bytes()))?)
+            } else {
+                println!("Initializing RLN with default config");
+                Some(RLN::new(tree_height, Cursor::new(json!({}).to_string()))?)
+            };
             Ok(())
         }
         Some(Commands::NewWithParams {
             tree_height,
-            config,
-            tree_config_input,
+            resources_path,
         }) => {
             let mut resources: Vec<Vec<u8>> = Vec::new();
             #[cfg(feature = "arkzkey")]
-            let filenames = ["rln.wasm", "rln_final.arkzkey", "verification_key.json"];
+            let filenames = ["rln_final.arkzkey", "graph.bin"];
             #[cfg(not(feature = "arkzkey"))]
-            let filenames = ["rln.wasm", "rln_final.zkey", "verification_key.json"];
+            let filenames = ["rln_final.zkey", "graph.bin"];
             for filename in filenames {
-                let fullpath = config.join(Path::new(filename));
+                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 mut output_buffer = vec![0; metadata.len() as usize];
+                file.read_exact(&mut output_buffer)?;
+                resources.push(output_buffer);
             }
-            let tree_config_input_file = File::open(&tree_config_input)?;
-            state.rln = Some(RLN::new_with_params(
-                *tree_height,
-                resources[0].clone(),
-                resources[1].clone(),
-                resources[2].clone(),
-                tree_config_input_file,
-            )?);
+            let config = Config::load_config()?;
+            if let Some(InnerConfig {
+                tree_height,
+                tree_config,
+            }) = config.inner
+            {
+                println!("Initializing RLN with custom config");
+                state.rln = Some(RLN::new_with_params(
+                    tree_height,
+                    resources[0].clone(),
+                    resources[1].clone(),
+                    Cursor::new(tree_config.to_string().as_bytes()),
+                )?)
+            } else {
+                println!("Initializing RLN with default config");
+                state.rln = Some(RLN::new_with_params(
+                    tree_height,
+                    resources[0].clone(),
+                    resources[1].clone(),
+                    Cursor::new(json!({}).to_string()),
+                )?)
+            };
             Ok(())
         }
         Some(Commands::SetTree { tree_height }) => {
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
-                .set_tree(*tree_height)?;
+                .set_tree(tree_height)?;
             Ok(())
         }
-        Some(Commands::SetLeaf { index, file }) => {
-            let input_data = File::open(&file)?;
+        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)?;
+                .set_leaf(index, input_data)?;
             Ok(())
         }
-        Some(Commands::SetMultipleLeaves { index, file }) => {
-            let input_data = File::open(&file)?;
+        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)?;
+                .set_leaves_from(index, input_data)?;
             Ok(())
         }
-        Some(Commands::ResetMultipleLeaves { file }) => {
-            let input_data = File::open(&file)?;
+        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 { file }) => {
-            let input_data = File::open(&file)?;
+        Some(Commands::SetNextLeaf { input }) => {
+            let input_data = File::open(input)?;
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
@@ -102,60 +130,73 @@ fn main() -> Result<()> {
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
-                .delete_leaf(*index)?;
-            Ok(())
-        }
-        Some(Commands::GetRoot) => {
-            let writer = std::io::stdout();
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .get_root(writer)?;
-            Ok(())
-        }
-        Some(Commands::GetProof { index }) => {
-            let writer = std::io::stdout();
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .get_proof(*index, writer)?;
+                .delete_leaf(index)?;
             Ok(())
         }
         Some(Commands::Prove { input }) => {
-            let input_data = File::open(&input)?;
-            let writer = std::io::stdout();
+            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, writer)?;
+                .prove(input_data, &mut output_buffer)?;
+            let proof = output_buffer.into_inner();
+            println!("proof: {:?}", proof);
             Ok(())
         }
-        Some(Commands::Verify { file }) => {
-            let input_data = File::open(&file)?;
-            state
+        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 writer = std::io::stdout();
+            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, writer)?;
+                .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)?;
+            let input_data = File::open(input)?;
+            let roots_data = File::open(roots)?;
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
                 .verify_with_roots(input_data, roots_data)?;
             Ok(())
         }
+        Some(Commands::GetRoot) => {
+            let mut output_buffer = Cursor::new(Vec::<u8>::new());
+            state
+                .rln
+                .ok_or(Report::msg("no RLN instance initialized"))?
+                .get_root(&mut output_buffer)
+                .unwrap();
+            let (root, _) = bytes_le_to_fr(&output_buffer.into_inner());
+            println!("root: {root}");
+            Ok(())
+        }
+        Some(Commands::GetProof { index }) => {
+            let mut output_buffer = Cursor::new(Vec::<u8>::new());
+            state
+                .rln
+                .ok_or(Report::msg("no RLN instance initialized"))?
+                .get_proof(index, &mut output_buffer)?;
+            let output_buffer_inner = output_buffer.into_inner();
+            let (path_elements, _) = bytes_le_to_vec_fr(&output_buffer_inner)?;
+            for (index, element) in path_elements.iter().enumerate() {
+                println!("path element {}: {}", index, element);
+            }
+            Ok(())
+        }
         None => Ok(()),
     }
 }

rln-cli/src/state.rs

@@ -1,20 +1,20 @@
+use std::io::Cursor;
+
 use color_eyre::Result;
 use rln::public::RLN;
-use std::fs::File;
 
 use crate::config::{Config, InnerConfig};
 
 #[derive(Default)]
-pub(crate) struct State<'a> {
-    pub rln: Option<RLN<'a>>,
+pub(crate) struct State {
+    pub rln: Option<RLN>,
 }
 
-impl<'a> State<'a> {
-    pub(crate) fn load_state() -> Result<State<'a>> {
+impl State {
+    pub(crate) fn load_state() -> Result<State> {
         let config = Config::load_config()?;
-        let rln = if let Some(InnerConfig { file, tree_height }) = config.inner {
-            let resources = File::open(&file)?;
-            Some(RLN::new(tree_height, resources)?)
+        let rln = if let Some(InnerConfig { tree_height, .. }) = config.inner {
+            Some(RLN::new(tree_height, Cursor::new(config.as_bytes()))?)
         } else {
             None
         };

rln-wasm/.gitignore

@@ -1,6 +0,0 @@
-/target
-**/*.rs.bk
-Cargo.lock
-bin/
-pkg/
-wasm-pack.log

rln-wasm/Cargo.toml

@@ -1,35 +0,0 @@
-[package]
-name = "rln-wasm"
-version = "0.0.13"
-edition = "2021"
-license = "MIT or Apache2"
-autobenches = false
-autotests = false
-autobins = false
-
-[lib]
-crate-type = ["cdylib", "rlib"]
-
-[features]
-default = ["console_error_panic_hook"]
-
-[dependencies]
-rln = { path = "../rln", default-features = false, features = ["wasm"] }
-num-bigint = { version = "0.4", default-features = false, features = ["rand", "serde"] }
-wasmer = { version = "2.3", default-features = false, features = ["js", "std"] }
-web-sys = {version = "0.3", features=["console"]}
-getrandom = { version = "0.2.7", default-features = false, features = ["js"] }
-wasm-bindgen = "0.2.63"
-serde-wasm-bindgen = "0.4"
-js-sys = "0.3.59"
-serde_json = "1.0.85"
-
-# The `console_error_panic_hook` crate provides better debugging of panics by
-# logging them with `console.error`. This is great for development, but requires
-# all the `std::fmt` and `std::panicking` infrastructure, so isn't great for
-# code size when deploying.
-console_error_panic_hook = { version = "0.1.7", optional = true }
-
-[dev-dependencies]
-wasm-bindgen-test = "0.3.13"
-wasm-bindgen-futures = "0.4.33"

rln-wasm/Makefile.toml

@@ -1,35 +0,0 @@
-[tasks.pack-build]
-command = "wasm-pack"
-args = ["build", "--release", "--target", "web", "--scope", "waku"]
-
-[tasks.pack-rename]
-script = "sed -i.bak 's/rln-wasm/zerokit-rln-wasm/g' pkg/package.json && rm pkg/package.json.bak"
-
-[tasks.build]
-clear = true
-dependencies = [
-    "pack-build",
-    "pack-rename",
-    "post-build"
-]
-
-[tasks.post-build]
-command = "wasm-strip"
-args = ["./pkg/rln_wasm_bg.wasm"]
-
-[tasks.test]
-command = "wasm-pack"
-args = ["test", "--release", "--node"]
-dependencies = ["build"]
-
-[tasks.login]
-command = "wasm-pack"
-args = ["login"]
-
-[tasks.publish]
-command = "wasm-pack"
-args = ["publish", "--access", "public", "--target", "web"]
-
-[tasks.bench]
-command = "echo"
-args = ["'No benchmarks available for this project'"]

rln-wasm/README.md

@@ -1,41 +0,0 @@
-# RLN for WASM
-This library is used in [waku-org/js-rln](https://github.com/waku-org/js-rln/)
-
-## Building the library
-1. Install `wasm-pack`
-```
-curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
-```
-2. Install `cargo-make`
-```
-cargo install cargo-make
-```
-
-OR
-
-```
-make installdeps
-```
-3. Compile zerokit for `wasm32-unknown-unknown`:
-```
-cd rln-wasm
-cargo make build
-```
-4. Compile a slimmer version of zerokit for `wasm32-unknown-unknown`:
-```
-cd rln-wasm
-cargo make post-build
-```
-
-## Running tests
-```
-cd rln-wasm
-cargo make test
-```
-
-## Publishing a npm package
-```
-cd rln-wasm
-cargo make login
-cargo make publish
-```

rln-wasm/resources/witness_calculator.js

@@ -1,331 +0,0 @@
-module.exports = 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

@@ -1,406 +0,0 @@
-#![cfg(target_arch = "wasm32")]
-
-extern crate wasm_bindgen;
-extern crate web_sys;
-
-use std::vec::Vec;
-
-use js_sys::{BigInt as JsBigInt, Object, Uint8Array};
-use num_bigint::BigInt;
-use rln::public::{hash, poseidon_hash, RLN};
-use wasm_bindgen::prelude::*;
-
-#[wasm_bindgen]
-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<'static>,
-}
-
-// 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: {:#?}", $error_msg, err))
-            } else {
-                let result = Uint8Array::from(&output_data[..]);
-                std::mem::forget(output_data);
-                Ok(result)
-            }
-        }
-    };
-}
-
-// Macro to call_with_error_msg methods with arbitrary amount of arguments,
-// First argument to the macro is context,
-// second is the actual method on `RLNWrapper`
-// rest are all other arguments to the method
-macro_rules! call_with_error_msg {
-    ($instance:expr, $method:ident, $error_msg:expr $(, $arg:expr)*) => {
-        {
-            let new_instance: &mut RLNWrapper = $instance.process();
-            if let Err(err) = new_instance.instance.$method($($arg.process()),*) {
-                Err(format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-            } else {
-                Ok(())
-            }
-
-        }
-    }
-}
-
-macro_rules! call {
-    ($instance:expr, $method:ident $(, $arg:expr)*) => {
-        {
-            let new_instance: &mut RLNWrapper = $instance.process();
-            new_instance.instance.$method($($arg.process()),*)
-        }
-    }
-}
-
-macro_rules! call_bool_method_with_error_msg {
-    ($instance:expr, $method:ident, $error_msg:expr $(, $arg:expr)*) => {
-        {
-            let new_instance: &RLNWrapper = $instance.process();
-            new_instance.instance.$method($($arg.process()),*).map_err(|err| format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-        }
-    }
-}
-
-// Macro to execute a function with arbitrary amount of arguments,
-// First argument is the function to execute
-// Rest are all other arguments to the method
-macro_rules! fn_call_with_output_and_error_msg {
-    // this variant is needed for the case when
-    // there are zero other arguments
-    ($func:ident, $error_msg:expr) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            if let Err(err) = $func(&mut output_data) {
-                std::mem::forget(output_data);
-                Err(format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-            } else {
-                let result = Uint8Array::from(&output_data[..]);
-                std::mem::forget(output_data);
-                Ok(result)
-            }
-        }
-    };
-    ($func:ident, $error_msg:expr, $( $arg:expr ),* ) => {
-        {
-            let mut output_data: Vec<u8> = Vec::new();
-            if let Err(err) = $func($($arg.process()),*, &mut output_data) {
-                std::mem::forget(output_data);
-                Err(format!("Msg: {:#?}, Error: {:#?}", $error_msg, err))
-            } else {
-                let result = Uint8Array::from(&output_data[..]);
-                std::mem::forget(output_data);
-                Ok(result)
-            }
-        }
-    };
-}
-
-trait ProcessArg {
-    type ReturnType;
-    fn process(self) -> Self::ReturnType;
-}
-
-impl ProcessArg for usize {
-    type ReturnType = usize;
-    fn process(self) -> Self::ReturnType {
-        self
-    }
-}
-
-impl<T> ProcessArg for Vec<T> {
-    type ReturnType = Vec<T>;
-    fn process(self) -> Self::ReturnType {
-        self
-    }
-}
-
-impl<'a> ProcessArg for *const RLN<'a> {
-    type ReturnType = &'a RLN<'a>;
-    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(
-    tree_height: usize,
-    zkey: Uint8Array,
-    vk: Uint8Array,
-) -> Result<*mut RLNWrapper, String> {
-    let instance = RLN::new_with_params(tree_height, zkey.to_vec(), vk.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 = getSerializedRLNWitness)]
-pub fn wasm_get_serialized_rln_witness(
-    ctx: *mut RLNWrapper,
-    input: Uint8Array,
-) -> Result<Uint8Array, String> {
-    let rln_witness = call!(ctx, get_serialized_rln_witness, &input.to_vec()[..])
-        .map_err(|err| format!("{:#?}", err))?;
-    Ok(Uint8Array::from(&rln_witness[..]))
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = insertMember)]
-pub fn wasm_set_next_leaf(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(), String> {
-    call_with_error_msg!(
-        ctx,
-        set_next_leaf,
-        "could not insert member into merkle tree".to_string(),
-        &input.to_vec()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = setLeavesFrom)]
-pub fn wasm_set_leaves_from(
-    ctx: *mut RLNWrapper,
-    index: usize,
-    input: Uint8Array,
-) -> Result<(), String> {
-    call_with_error_msg!(
-        ctx,
-        set_leaves_from,
-        "could not set multiple leaves".to_string(),
-        index,
-        &*input.to_vec()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = deleteLeaf)]
-pub fn wasm_delete_leaf(ctx: *mut RLNWrapper, index: usize) -> Result<(), String> {
-    call_with_error_msg!(ctx, delete_leaf, "could not delete leaf".to_string(), index)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = setMetadata)]
-pub fn wasm_set_metadata(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(), String> {
-    call_with_error_msg!(
-        ctx,
-        set_metadata,
-        "could not set metadata".to_string(),
-        &*input.to_vec()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = getMetadata)]
-pub fn wasm_get_metadata(ctx: *mut RLNWrapper) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(ctx, get_metadata, "could not get metadata".to_string())
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = initTreeWithLeaves)]
-pub fn wasm_init_tree_with_leaves(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(), String> {
-    call_with_error_msg!(
-        ctx,
-        init_tree_with_leaves,
-        "could not init merkle tree".to_string(),
-        &*input.to_vec()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = RLNWitnessToJson)]
-pub fn rln_witness_to_json(
-    ctx: *mut RLNWrapper,
-    serialized_witness: Uint8Array,
-) -> Result<Object, String> {
-    let inputs = call!(ctx, get_rln_witness_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]
-pub fn generate_rln_proof_with_witness(
-    ctx: *mut RLNWrapper,
-    calculated_witness: Vec<JsBigInt>,
-    serialized_witness: Uint8Array,
-) -> Result<Uint8Array, String> {
-    let mut witness_vec: Vec<BigInt> = vec![];
-
-    for v in calculated_witness {
-        witness_vec.push(
-            v.to_string(10)
-                .map_err(|err| format!("{:#?}", err))?
-                .as_string()
-                .ok_or("not a string error")?
-                .parse::<BigInt>()
-                .map_err(|err| format!("{:#?}", err))?,
-        );
-    }
-
-    call_with_output_and_error_msg!(
-        ctx,
-        generate_rln_proof_with_witness,
-        "could not generate proof",
-        witness_vec,
-        serialized_witness.to_vec()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateMembershipKey)]
-pub fn wasm_key_gen(ctx: *const RLNWrapper) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(ctx, key_gen, "could not generate membership keys")
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateExtendedMembershipKey)]
-pub fn wasm_extended_key_gen(ctx: *const RLNWrapper) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(ctx, extended_key_gen, "could not generate membership keys")
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateSeededMembershipKey)]
-pub fn wasm_seeded_key_gen(ctx: *const RLNWrapper, seed: Uint8Array) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(
-        ctx,
-        seeded_key_gen,
-        "could not generate membership key",
-        &seed.to_vec()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = generateSeededExtendedMembershipKey)]
-pub fn wasm_seeded_extended_key_gen(
-    ctx: *const RLNWrapper,
-    seed: Uint8Array,
-) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(
-        ctx,
-        seeded_extended_key_gen,
-        "could not generate membership key",
-        &seed.to_vec()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = recovedIDSecret)]
-pub fn wasm_recover_id_secret(
-    ctx: *const RLNWrapper,
-    input_proof_data_1: Uint8Array,
-    input_proof_data_2: Uint8Array,
-) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(
-        ctx,
-        recover_id_secret,
-        "could not recover id secret",
-        &input_proof_data_1.to_vec()[..],
-        &input_proof_data_2.to_vec()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = verifyRLNProof)]
-pub fn wasm_verify_rln_proof(ctx: *const RLNWrapper, proof: Uint8Array) -> Result<bool, String> {
-    call_bool_method_with_error_msg!(
-        ctx,
-        verify_rln_proof,
-        "error while verifying rln proof".to_string(),
-        &proof.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()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = getRoot)]
-pub fn wasm_get_root(ctx: *const RLNWrapper) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(ctx, get_root, "could not obtain root")
-}
-
-#[wasm_bindgen(js_name = hash)]
-pub fn wasm_hash(input: Uint8Array) -> Result<Uint8Array, String> {
-    fn_call_with_output_and_error_msg!(hash, "could not generate hash", &input.to_vec()[..])
-}
-
-#[wasm_bindgen(js_name = poseidonHash)]
-pub fn wasm_poseidon_hash(input: Uint8Array) -> Result<Uint8Array, String> {
-    fn_call_with_output_and_error_msg!(
-        poseidon_hash,
-        "could not generate poseidon hash",
-        &input.to_vec()[..]
-    )
-}

rln-wasm/src/utils.js

@@ -1,18 +0,0 @@
-const fs = require("fs");
-
-// Utils functions for loading circom witness calculator and reading files from test
-
-module.exports = {
-    read_file: function (path) {
-        return fs.readFileSync(path);
-    },
-
-    calculateWitness: async function(circom_path, inputs){
-        const wc = require("resources/witness_calculator.js");
-        const wasmFile = fs.readFileSync(circom_path);
-        const wasmFileBuffer = wasmFile.slice(wasmFile.byteOffset, wasmFile.byteOffset + wasmFile.byteLength);
-        const witnessCalculator = await wc(wasmFileBuffer);
-        const calculatedWitness = await witnessCalculator.calculateWitness(inputs, false);
-        return JSON.stringify(calculatedWitness, (key, value) => typeof value === "bigint" ? value.toString() : value);
-    }
-}

rln-wasm/tests/rln-wasm.rs

@@ -1,148 +0,0 @@
-#![cfg(target_arch = "wasm32")]
-
-#[cfg(test)]
-mod tests {
-    use js_sys::{BigInt as JsBigInt, Object, Uint8Array};
-    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
-    use rln::hashers::{hash_to_field, poseidon_hash};
-    use rln::utils::{bytes_le_to_fr, fr_to_bytes_le, normalize_usize};
-    use rln_wasm::*;
-    use wasm_bindgen::{prelude::*, JsValue};
-    use wasm_bindgen_test::wasm_bindgen_test;
-
-    #[wasm_bindgen(module = "src/utils.js")]
-    extern "C" {
-        #[wasm_bindgen(catch)]
-        fn read_file(path: &str) -> Result<Uint8Array, JsValue>;
-
-        #[wasm_bindgen(catch)]
-        async fn calculateWitness(circom_path: &str, input: Object) -> Result<JsValue, JsValue>;
-    }
-
-    #[wasm_bindgen_test]
-    pub async fn test_basic_flow() {
-        let tree_height = TEST_TREE_HEIGHT;
-        let circom_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln.wasm");
-        let zkey_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln_final.zkey");
-        let vk_path =
-            format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/verification_key.json");
-        let zkey = read_file(&zkey_path).unwrap();
-        let vk = read_file(&vk_path).unwrap();
-
-        // Creating an instance of RLN
-        let rln_instance = wasm_new(tree_height, zkey, vk).unwrap();
-
-        // Creating membership key
-        let mem_keys = wasm_key_gen(rln_instance).unwrap();
-        let id_key = mem_keys.subarray(0, 32);
-        let id_commitment = mem_keys.subarray(32, 64);
-
-        // Prepare the message
-        let signal = b"Hello World";
-
-        let identity_index: usize = 0;
-        // Setting up the epoch and rln_identifier
-        let epoch = hash_to_field(b"test-epoch");
-        let rln_identifier = hash_to_field(b"test-rln-identifier");
-
-        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
-        let external_nullifier = fr_to_bytes_le(&external_nullifier);
-
-        let user_message_limit = Fr::from(100);
-        let message_id = fr_to_bytes_le(&Fr::from(0));
-
-        let (id_commitment_fr, _) = bytes_le_to_fr(&id_commitment.to_vec()[..]);
-        let rate_commitment = poseidon_hash(&[id_commitment_fr, user_message_limit]);
-
-        // Insert PK
-        wasm_set_next_leaf(
-            rln_instance,
-            Uint8Array::from(fr_to_bytes_le(&rate_commitment).as_slice()),
-        )
-        .unwrap();
-
-        // Serializing the message
-        let mut serialized_vec: Vec<u8> = Vec::new();
-        serialized_vec.append(&mut id_key.to_vec());
-        serialized_vec.append(&mut normalize_usize(identity_index));
-        serialized_vec.append(&mut fr_to_bytes_le(&user_message_limit).to_vec());
-        serialized_vec.append(&mut message_id.to_vec());
-        serialized_vec.append(&mut external_nullifier.to_vec());
-        serialized_vec.append(&mut normalize_usize(signal.len()));
-        serialized_vec.append(&mut signal.to_vec());
-        let serialized_message = Uint8Array::from(&serialized_vec[..]);
-
-        let serialized_rln_witness =
-            wasm_get_serialized_rln_witness(rln_instance, serialized_message).unwrap();
-
-        // Obtaining inputs that should be sent to circom witness calculator
-        let json_inputs =
-            rln_witness_to_json(rln_instance, serialized_rln_witness.clone()).unwrap();
-
-        // Calculating witness with JS
-        // (Using a JSON since wasm_bindgen does not like Result<Vec<JsBigInt>,JsValue>)
-        let calculated_witness_json = calculateWitness(&circom_path, json_inputs)
-            .await
-            .unwrap()
-            .as_string()
-            .unwrap();
-        let calculated_witness_vec_str: Vec<String> =
-            serde_json::from_str(&calculated_witness_json).unwrap();
-        let calculated_witness: Vec<JsBigInt> = calculated_witness_vec_str
-            .iter()
-            .map(|x| JsBigInt::new(&x.into()).unwrap())
-            .collect();
-
-        // Generating proof
-        let proof = generate_rln_proof_with_witness(
-            rln_instance,
-            calculated_witness.into(),
-            serialized_rln_witness,
-        )
-        .unwrap();
-
-        // Add signal_len | signal
-        let mut proof_bytes = proof.to_vec();
-        proof_bytes.append(&mut normalize_usize(signal.len()));
-        proof_bytes.append(&mut signal.to_vec());
-        let proof_with_signal = Uint8Array::from(&proof_bytes[..]);
-
-        // Validate Proof
-        let is_proof_valid = wasm_verify_rln_proof(rln_instance, proof_with_signal);
-
-        assert!(
-            is_proof_valid.unwrap(),
-            "validating proof generated with wasm failed"
-        );
-
-        // Validating Proof with Roots
-        let root = wasm_get_root(rln_instance).unwrap();
-        let roots = Uint8Array::from(&root.to_vec()[..]);
-        let proof_with_signal = Uint8Array::from(&proof_bytes[..]);
-
-        let is_proof_valid = wasm_verify_with_roots(rln_instance, proof_with_signal, roots);
-        assert!(is_proof_valid.unwrap(), "verifying proof with roots failed");
-    }
-
-    #[wasm_bindgen_test]
-    fn test_metadata() {
-        let tree_height = TEST_TREE_HEIGHT;
-        let zkey_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln_final.zkey");
-        let vk_path =
-            format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/verification_key.json");
-        let zkey = read_file(&zkey_path).unwrap();
-        let vk = read_file(&vk_path).unwrap();
-
-        // Creating an instance of RLN
-        let rln_instance = wasm_new(tree_height, zkey, vk).unwrap();
-
-        let test_metadata = Uint8Array::new(&JsValue::from_str("test"));
-        // Inserting random metadata
-        wasm_set_metadata(rln_instance, test_metadata.clone()).unwrap();
-
-        // Getting metadata
-        let metadata = wasm_get_metadata(rln_instance).unwrap();
-
-        assert_eq!(metadata.to_vec(), test_metadata.to_vec());
-    }
-}

rln/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rln"
-version = "0.5.0"
+version = "0.7.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
@@ -15,57 +15,54 @@ bench = false
 # This flag disable cargo doctests, i.e. testing example code-snippets in documentation
 doctest = false
 
-
 [dependencies]
 # ZKP Generation
-ark-ec = { version = "=0.4.1", default-features = false }
-ark-ff = { version = "=0.4.1", default-features = false, features = ["asm"] }
-ark-std = { version = "=0.4.0", default-features = false }
-ark-bn254 = { version = "=0.4.0" }
-ark-groth16 = { version = "=0.4.0", features = [
+ark-bn254 = { version = "0.5.0", features = ["std"] }
+ark-ff = { version = "0.5.0", features = ["std", "asm"] }
+ark-serialize = { version = "0.5.0", features = ["derive"] }
+ark-ec = { version = "0.5.0", default-features = false }
+ark-std = { version = "0.5.0", default-features = false }
+ark-groth16 = { version = "0.5.0", features = [
     "parallel",
 ], default-features = false }
-ark-relations = { version = "=0.4.0", default-features = false, features = [
+ark-relations = { version = "0.5.0", default-features = false, features = [
     "std",
 ] }
-ark-serialize = { version = "=0.4.1", default-features = false }
-ark-circom = { version = "=0.1.0", default-features = false, features = [
-    "circom-2",
-] }
-ark-zkey = { version = "0.1.0", optional = true, default-features = false }
-
-# WASM
-wasmer = { version = "=2.3.0", default-features = false }
+ark-circom = { version = "0.5.0" }
+ark-r1cs-std = { version = "0.5.0" }
 
 # error handling
-color-eyre = "=0.6.2"
-thiserror = "=1.0.39"
+color-eyre = "0.6.2"
+thiserror = "2.0.11"
 
 # utilities
-cfg-if = "=1.0"
-num-bigint = { version = "=0.4.3", default-features = false, features = [
+byteorder = "1.4.3"
+cfg-if = "1.0"
+num-bigint = { version = "0.4.6", default-features = false, features = [
     "rand",
 ] }
-num-traits = "=0.2.15"
-once_cell = "=1.17.1"
-rand = "=0.8.5"
-rand_chacha = "=0.3.1"
-tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
-utils = { package = "zerokit_utils", version = "=0.5.0", path = "../utils/", default-features = false }
-
+num-traits = "0.2.19"
+once_cell = "1.19.0"
+lazy_static = "1.4.0"
+rand = "0.8.5"
+rand_chacha = "0.3.1"
+ruint = { version = "1.12.4", features = ["rand", "serde", "ark-ff-04"] }
+tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+utils = { package = "zerokit_utils", version = "0.5.2", path = "../utils/", default-features = false }
 
 # serialization
-serde_json = "=1.0.96"
-serde = { version = "=1.0.163", features = ["derive"] }
+prost = "0.13.1"
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
 
-include_dir = "=0.7.3"
+document-features = { version = "=0.2.10", optional = true }
 
 [dev-dependencies]
-sled = "=0.34.7"
-criterion = { version = "=0.4.0", features = ["html_reports"] }
+sled = "0.34.7"
+criterion = { version = "0.4.0", features = ["html_reports"] }
 
 [features]
-default = ["parallel", "wasmer/sys-default", "pmtree-ft"]
+default = ["parallel", "pmtree-ft"]
 parallel = [
     "ark-ec/parallel",
     "ark-ff/parallel",
@@ -73,9 +70,9 @@ parallel = [
     "ark-groth16/parallel",
     "utils/parallel",
 ]
-wasm = ["wasmer/js", "wasmer/std"]
 fullmerkletree = ["default"]
-arkzkey = ["ark-zkey"]
+arkzkey = []
+stateless = []
 
 # Note: pmtree feature is still experimental
 pmtree-ft = ["utils/pmtree-ft"]
@@ -88,6 +85,14 @@ harness = false
 name = "circuit_loading_benchmark"
 harness = false
 
+[[bench]]
+name = "circuit_loading_arkzkey_benchmark"
+harness = false
+required-features = ["arkzkey"]
+
 [[bench]]
 name = "poseidon_tree_benchmark"
 harness = false
+
+[package.metadata.docs.rs]
+all-features = true

rln/Makefile.toml

@@ -4,7 +4,15 @@ args = ["build", "--release"]
 
 [tasks.test]
 command = "cargo"
-args = ["test", "--release"]
+args = ["test", "--release", "--", "--nocapture"]
+
+[tasks.test_stateless]
+command = "cargo"
+args = ["test", "--release", "--features", "stateless"]
+
+[tasks.test_arkzkey]
+command = "cargo"
+args = ["test", "--release", "--features", "arkzkey"]
 
 [tasks.bench]
 command = "cargo"

rln/README.md

@@ -1,65 +1,17 @@
 # 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)
 
-## Pre-requisites
+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:
 
-### Install dependencies and clone repo
+- Generate and verify RLN proofs
+- Work with Merkle trees for commitment storage
+- Implement rate-limiting mechanisms for distributed systems
 
-```sh
-make installdeps
-git clone https://github.com/vacp2p/zerokit.git
-cd zerokit/rln
-```
+## Quick Start
 
-### Build and Test
-
-To build and test, run the following commands within the module folder
-
-```bash
-cargo make build
-cargo make test
-```
-
-### Compile ZK circuits
-
-The `rln` (https://github.com/rate-limiting-nullifier/circom-rln) repository, which contains the RLN circuit implementation is a submodule of zerokit RLN.
-
-To compile the RLN circuit
-
-```sh
-# Update submodules
-git submodule update --init --recursive
-
-# Install rln dependencies
-cd vendor/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
-```
-
-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 `vendor/rln/circuit/rln.circom`.
-
-In order to compile a RLN circuit with Merkle tree height `N`, it suffices to change `vendor/rln/circuit/rln.circom` to
-
-```
-pragma circom 2.0.0;
-
-include "./rln-base.circom";
-
-component main {public [x, epoch, rln_identifier ]} = RLN(N);
-```
-
-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.
-
-Currently, the `rln` module comes with 2 [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) RLN circuits having Merkle tree of height `20` and `32`, respectively.
-
-## Getting started
+> [!IMPORTANT]
+> Version 0.6.1 is required for WASM support or x32 architecture. Current version doesn't support these platforms due to dependency issues. WASM support will return in a future release.
 
 ### Add RLN as dependency
 
@@ -70,136 +22,236 @@ We start by adding zerokit RLN to our `Cargo.toml`
 rln = { git = "https://github.com/vacp2p/zerokit" }
 ```
 
-### Create a RLN object
+## Basic Usage Example
 
-First, we need to create a RLN object for a chosen input Merkle tree size.
-
-Note that we need to pass to RLN object constructor the path where the circuit (`rln.wasm`, built for the input tree size), the corresponding proving key (`rln_final.zkey`) or (`rln_final.arkzkey`) and verification key (`verification_key.json`, optional) are found.
+Note that we need to pass to RLN object constructor the path where the graph file (`graph.bin`, built for the input tree size), the corresponding proving key (`rln_final.zkey`) or (`rln_final_uncompr.arkzkey`) and verification key (`verification_key.arkvkey`, optional) are found.
 
 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 rln::protocol::*;
-use rln::public::*;
 use std::io::Cursor;
 
-// We set the RLN parameters:
-// - the tree height;
-// - the tree config, if it is not defined, the default value will be set
-let tree_height = 20;
-let input = Cursor::new(json!({}).to_string());
+use rln::{
+    circuit::Fr,
+    hashers::{hash_to_field, poseidon_hash},
+    protocol::{keygen, prepare_verify_input},
+    public::RLN,
+    utils::{fr_to_bytes_le, normalize_usize},
+};
+use serde_json::json;
 
-// We create a new RLN instance
-let mut rln = RLN::new(tree_height, input);
+fn main() {
+    // 1. Initialize RLN with parameters:
+    // - the tree height;
+    // - the tree config, if it is not defined, the default value will be set
+    let tree_height = 20;
+    let input = Cursor::new(json!({}).to_string());
+    let mut rln = RLN::new(tree_height, input).unwrap();
+
+    // 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 = 10;
+    let rate_commitment = poseidon_hash(&[id_commitment, Fr::from(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");
+    let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+
+    // 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 mut serialized: Vec<u8> = Vec::new();
+    serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
+    serialized.append(&mut normalize_usize(id_index));
+    serialized.append(&mut fr_to_bytes_le(&Fr::from(user_message_limit)));
+    serialized.append(&mut fr_to_bytes_le(&Fr::from(1)));
+    serialized.append(&mut fr_to_bytes_le(&external_nullifier));
+    serialized.append(&mut normalize_usize(signal.len()));
+    serialized.append(&mut signal.to_vec());
+
+    // 7. Generate a RLN proof
+    // We generate a RLN proof for proof_input
+    let mut input_buffer = Cursor::new(serialized);
+    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);
+}
 ```
 
-### Generate an identity keypair
-
-We generate an identity keypair
-
-```rust
-// We generate an identity pair
-let mut buffer = Cursor::new(Vec::<u8>::new());
-rln.key_gen(&mut buffer).unwrap();
-
-// We deserialize the keygen output to obtain
-// the identity_secret and id_commitment
-let (identity_secret_hash, id_commitment) = deserialize_identity_pair(buffer.into_inner());
-```
-
-### Add Rate commitment to the RLN Merkle tree
-
-```rust
-// We define the tree index where id_commitment will be added
-let id_index = 10;
-let user_message_limit = 10;
-
-// We serialize id_commitment and pass it to set_leaf
-let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
-let mut buffer = Cursor::new(serialize_field_element(rate_commitment));
-rln.set_leaf(id_index, &mut buffer).unwrap();
-```
-
-Note that when tree leaves are not explicitly set by the user (in this example, all those with index less and greater than `10`), their values is set to an hardcoded default (all-`0` bytes in current implementation).
-
-### Set external nullifier
+### 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 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.
 
-```rust
-// 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");
+### Features
 
-let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+- **Multiple Backend Support**: Choose between different zkey formats with feature flags
+  - `arkzkey`: Use the optimized Arkworks-compatible zkey format (faster loading)
+  - `stateless`: For stateless proof verification
+- **Pre-compiled Circuits**: Ready-to-use circuits with Merkle tree height of 20
+
+## Building and Testing
+
+### Prerequisites
+
+```sh
+git clone https://github.com/vacp2p/zerokit.git
+make installdeps
+cd zerokit/rln
 ```
 
-### Set signal
+### Build Commands
 
-The signal is the message for which we are computing a RLN proof.
+```sh
+# Build with default features
+cargo make build
 
-```rust
-// We set our signal
-let signal = b"RLN is awesome";
+# Test with default features
+cargo make test
+
+# Test with specific features
+cargo make test_arkzkey    # For arkzkey feature
+cargo make test_stateless  # For stateless feature
 ```
 
-### Generate a RLN proof
+## Advanced: Custom Circuit Compilation
 
-We prepare the input to the proof generation routine.
+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.
 
-Input buffer is serialized as `[ identity_key | id_index | external_nullifier | user_message_limit | message_id | signal_len | signal ]`.
+### 1. Compile ZK Circuits for getting the zkey and verification key files
 
-```rust
-// We prepare input to the proof generation routine
-let proof_input = prepare_prove_input(identity_secret_hash, id_index, external_nullifier, signal);
+This script actually generates not only the zkey and verification key files for the RLN circuit, but also the execution wasm file used for witness calculation.
+However, the wasm file is not needed for the `rln` module, because current implementation uses the iden3 graph file for witness calculation.
+This 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);
 ```
 
-We are now ready to generate a RLN ZK proof along with the _public outputs_ of the ZK circuit evaluation.
+Where:
 
-```rust
+- `N`: Merkle tree height, determining the maximum membership capacity (2^N members).
 
-// We generate a RLN proof for proof_input
-let mut in_buffer = Cursor::new(proof_input);
-let mut out_buffer = Cursor::new(Vec::<u8>::new());
-rln.generate_rln_proof(&mut in_buffer, &mut out_buffer)
-    .unwrap();
+- `M`: Bit size for range checks, setting an upper bound for the number of messages per epoch (2^M messages).
 
-// We get the public outputs returned by the circuit evaluation
-let proof_data = out_buffer.into_inner();
+> [!NOTE]
+> However, if `N` is too big, this might require a larger Powers of Tau ceremony than the one hardcoded in `./scripts/build-circuits.sh`, which is `2^14`. \
+> In such case, we refer to the official [Circom documentation](https://docs.circom.io/getting-started/proving-circuits/#powers-of-tau) for instructions on how to run an appropriate Powers of Tau ceremony and Phase 2 in order to compile the desired circuit. \
+> Additionally, while `M` sets an upper bound on the number of messages per epoch (`2^M`), you can configure lower message limit for your use case, as long as it satisfies `user_message_limit ≤ 2^M`. \
+> Currently, the `rln` module comes with a [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) RLN circuit with a Merkle tree of height `20` and a bit size of `16`, allowing up to `2^20` registered members and a `2^16` message limit per epoch.
+
+#### 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
 ```
 
-The byte vector `proof_data` is serialized as `[ zk-proof | tree_root | external_nullifier | share_x | share_y | nullifier ]`.
+#### Generate the zkey and verification key files example
 
-### Verify a RLN proof
+```sh
+# Clone the circom-rln repository
+git clone https://github.com/rate-limiting-nullifier/circom-rln
 
-We prepare the input to the proof verification routine.
+# Install dependencies
+cd circom-rln && npm install
 
-Input buffer is serialized as `[proof_data | signal_len | signal ]`, where `proof_data` is (computed as) the output obtained by `generate_rln_proof`.
+# Build circuits
+./scripts/build-circuits.sh rln
 
-```rust
-// We prepare input to the proof verification routine
-let verify_data = prepare_verify_input(proof_data, signal);
-
-// We verify the zk-proof against the provided proof values
-let mut in_buffer = Cursor::new(verify_data);
-let verified = rln.verify(&mut in_buffer).unwrap();
+# Use the generated zkey file in subsequent steps
+cp zkeyFiles/rln/final.zkey <path_to_rln_final.zkey>
 ```
 
-We check if the proof verification was successful:
+### 2. Generate Witness Calculation Graph
 
-```rust
-// We ensure the proof is valid
-assert!(verified);
+The execution graph file used for witness calculation can be compiled following instructions in the [circom-witnesscalc](https://github.com/iden3/circom-witnesscalc) repository.
+As mentioned in step 1, we should use `rln.circom` file from `circom-rln` repository.
+
+```sh
+# Clone the circom-witnesscalc repository
+git clone https://github.com/iden3/circom-witnesscalc
+
+# Load the submodules
+cd circom-witnesscalc && git submodule update --init --recursive
+
+# 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>
 ```
 
-## Get involved!
+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 and verification key files
+
+For faster loading, compile the zkey file into the arkzkey format using [ark-zkey](https://github.com/seemenkina/ark-zkey). This is fork of the [original](https://github.com/zkmopro/ark-zkey) repository with the uncompressed zkey support.
+
+```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>
+```
+
+Currently, the `rln` module comes with [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) arkzkey keys for the RLN circuit.
+
+## Get involved
 
 Zerokit RLN public and FFI APIs allow interaction with many more features than what briefly showcased above.
 
@@ -210,3 +262,20 @@ 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/circuit_loading_arkzkey_benchmark.rs

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

rln/benches/circuit_loading_benchmark.rs

@@ -1,14 +1,24 @@
+use ark_circom::read_zkey;
 use criterion::{criterion_group, criterion_main, Criterion};
+use std::io::Cursor;
 
-// Depending on the key type (enabled by the `--features arkzkey` flag)
-// the upload speed from the `rln_final.zkey` or `rln_final.arkzkey` file is calculated
-pub fn key_load_benchmark(c: &mut Criterion) {
-    c.bench_function("zkey::upload_from_folder", |b| {
+pub fn zkey_load_benchmark(c: &mut Criterion) {
+    let zkey = rln::circuit::ZKEY_BYTES.to_vec();
+    let size = zkey.len() as f32;
+    println!("Size of zkey: {:.2?} MB", size / 1024.0 / 1024.0);
+
+    c.bench_function("zkey::zkey_from_raw", |b| {
         b.iter(|| {
-            let _ = rln::circuit::zkey_from_folder();
+            let mut reader = Cursor::new(zkey.clone());
+            let r = read_zkey(&mut reader);
+            assert_eq!(r.is_ok(), true);
         })
     });
 }
 
-criterion_group!(benches, key_load_benchmark);
+criterion_group! {
+    name = benches;
+    config = Criterion::default().sample_size(10);
+    targets = zkey_load_benchmark
+}
 criterion_main!(benches);

rln/resources/tree_height_20/verification_key.json

@@ -1,114 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 5,
- "vk_alpha_1": [
-  "20491192805390485299153009773594534940189261866228447918068658471970481763042",
-  "9383485363053290200918347156157836566562967994039712273449902621266178545958",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "6375614351688725206403948262868962793625744043794305715222011528459656738731",
-   "4252822878758300859123897981450591353533073413197771768651442665752259397132"
-  ],
-  [
-   "10505242626370262277552901082094356697409835680220590971873171140371331206856",
-   "21847035105528745403288232691147584728191162732299865338377159692350059136679"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "17077735495685170943380938230836408503627170115414840315502244846025577589191",
-   "14030085636943255545683322474441991939484590437387381169642530788494152024614"
-  ],
-  [
-   "11568745146423307387256571230823432454624378106569286849514884592874522611163",
-   "1838524899938769516485895655063198583192139511330418290063560641219523306282"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "2029413683389138792403550203267699914886160938906632433982220835551125967885",
-    "21072700047562757817161031222997517981543347628379360635925549008442030252106"
-   ],
-   [
-    "5940354580057074848093997050200682056184807770593307860589430076672439820312",
-    "12156638873931618554171829126792193045421052652279363021382169897324752428276"
-   ],
-   [
-    "7898200236362823042373859371574133993780991612861777490112507062703164551277",
-    "7074218545237549455313236346927434013100842096812539264420499035217050630853"
-   ]
-  ],
-  [
-   [
-    "7077479683546002997211712695946002074877511277312570035766170199895071832130",
-    "10093483419865920389913245021038182291233451549023025229112148274109565435465"
-   ],
-   [
-    "4595479056700221319381530156280926371456704509942304414423590385166031118820",
-    "19831328484489333784475432780421641293929726139240675179672856274388269393268"
-   ],
-   [
-    "11934129596455521040620786944827826205713621633706285934057045369193958244500",
-    "8037395052364110730298837004334506829870972346962140206007064471173334027475"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "4920513730204767532050733107749276406754520419375654722016092399980613788208",
-   "10950491564509418434657706642388934308456795265036074733953533582377584967294",
-   "1"
-  ],
-  [
-   "6815064660695497986531118446154820702646540722664044216580897159556261271171",
-   "17838140936832571103329556013529166877877534025488014783346458943575275015438",
-   "1"
-  ],
-  [
-   "16364982450206976302246609763791333525052810246590359380676749324389440643932",
-   "17092624338100676284548565502349491320314889021833923882585524649862570629227",
-   "1"
-  ],
-  [
-   "3679639231485547795420532910726924727560917141402837495597760107842698404034",
-   "16213191511474848247596810551723578773353083440353745908057321946068926848382",
-   "1"
-  ],
-  [
-   "9215428431027260354679105025212521481930206886203677270216204485256690813172",
-   "934602510541226149881779979217731465262250233587980565969044391353665291792",
-   "1"
-  ],
-  [
-   "8935861545794299876685457331391349387048184820319250771243971382360441890897",
-   "4993459033694759724715904486381952906869986989682015547152342336961693234616",
-   "1"
-  ]
- ]
-}

rln/src/circuit.rs

@@ -1,5 +1,6 @@
 // This crate provides interfaces for the zero-knowledge circuit and keys
 
+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,
@@ -8,41 +9,39 @@ use ark_groth16::{ProvingKey, VerifyingKey};
 use ark_relations::r1cs::ConstraintMatrices;
 use cfg_if::cfg_if;
 use color_eyre::{Report, Result};
-use num_bigint::BigUint;
-use serde_json::Value;
-use std::str::FromStr;
 
-cfg_if! {
-    if #[cfg(not(target_arch = "wasm32"))] {
-        use ark_circom::{WitnessCalculator};
-        use once_cell::sync::OnceCell;
-        use std::sync::Mutex;
-        use wasmer::{Module, Store};
-        use include_dir::{include_dir, Dir};
-        use std::path::Path;
-    }
+use crate::iden3calc::calc_witness;
+
+#[cfg(feature = "arkzkey")]
+use {
+    ark_ff::Field, ark_serialize::CanonicalDeserialize, ark_serialize::CanonicalSerialize,
+    color_eyre::eyre::WrapErr,
+};
+
+#[cfg(not(feature = "arkzkey"))]
+use {ark_circom::read_zkey, std::io::Cursor};
+
+#[cfg(feature = "arkzkey")]
+pub const ARKZKEY_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/rln_final.arkzkey");
+
+pub const ZKEY_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/rln_final.zkey");
+const GRAPH_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/graph.bin");
+
+lazy_static! {
+    static ref ZKEY: (ProvingKey<Curve>, ConstraintMatrices<Fr>) = {
+        cfg_if! {
+                if #[cfg(feature = "arkzkey")] {
+                    read_arkzkey_from_bytes_uncompressed(ARKZKEY_BYTES).expect("Failed to read arkzkey")
+                } else {
+                    let mut reader = Cursor::new(ZKEY_BYTES);
+                    read_zkey(&mut reader).expect("Failed to read zkey")
+                }
+        }
+    };
 }
 
-cfg_if! {
-    if #[cfg(feature = "arkzkey")] {
-        use ark_zkey::read_arkzkey_from_bytes;
-        const ARKZKEY_FILENAME: &str = "tree_height_20/rln_final.arkzkey";
-
-    } else {
-        use std::io::Cursor;
-        use ark_circom::read_zkey;
-    }
-}
-
-const ZKEY_FILENAME: &str = "tree_height_20/rln_final.zkey";
-const VK_FILENAME: &str = "tree_height_20/verification_key.json";
-const WASM_FILENAME: &str = "tree_height_20/rln.wasm";
-
 pub const TEST_TREE_HEIGHT: usize = 20;
 
-#[cfg(not(target_arch = "wasm32"))]
-static RESOURCES_DIR: Dir<'_> = include_dir!("$CARGO_MANIFEST_DIR/resources");
-
 // 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;
@@ -55,230 +54,120 @@ 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 proving_key_and_matrices = match () {
-            #[cfg(feature = "arkzkey")]
-            () => read_arkzkey_from_bytes(zkey_data.as_slice())?,
-            #[cfg(not(feature = "arkzkey"))]
-            () => {
-                let mut c = Cursor::new(zkey_data);
-                read_zkey(&mut c)?
-            }
-        };
-        Ok(proving_key_and_matrices)
-    } else {
-        Err(Report::msg("No proving key found!"))
+pub fn zkey_from_raw(zkey_data: &[u8]) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
+    if zkey_data.is_empty() {
+        return Err(Report::msg("No proving key found!"));
     }
+
+    let proving_key_and_matrices = match () {
+        #[cfg(feature = "arkzkey")]
+        () => read_arkzkey_from_bytes_uncompressed(zkey_data)?,
+        #[cfg(not(feature = "arkzkey"))]
+        () => {
+            let mut reader = Cursor::new(zkey_data);
+            read_zkey(&mut reader)?
+        }
+    };
+
+    Ok(proving_key_and_matrices)
 }
 
 // Loads the proving key
-#[cfg(not(target_arch = "wasm32"))]
-pub fn zkey_from_folder() -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
-    #[cfg(feature = "arkzkey")]
-    let zkey = RESOURCES_DIR.get_file(Path::new(ARKZKEY_FILENAME));
-    #[cfg(not(feature = "arkzkey"))]
-    let zkey = RESOURCES_DIR.get_file(Path::new(ZKEY_FILENAME));
-
-    if let Some(zkey) = zkey {
-        let proving_key_and_matrices = match () {
-            #[cfg(feature = "arkzkey")]
-            () => read_arkzkey_from_bytes(zkey.contents())?,
-            #[cfg(not(feature = "arkzkey"))]
-            () => {
-                let mut c = Cursor::new(zkey.contents());
-                read_zkey(&mut c)?
-            }
-        };
-        Ok(proving_key_and_matrices)
-    } else {
-        Err(Report::msg("No proving key found!"))
-    }
+pub fn zkey_from_folder() -> &'static (ProvingKey<Curve>, ConstraintMatrices<Fr>) {
+    &ZKEY
 }
 
 // Loads the verification key from a bytes vector
-pub fn vk_from_raw(vk_data: &[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() {
+pub fn vk_from_raw(zkey_data: &[u8]) -> Result<VerifyingKey<Curve>> {
+    if !zkey_data.is_empty() {
         let (proving_key, _matrices) = zkey_from_raw(zkey_data)?;
-        verifying_key = proving_key.vk;
-        Ok(verifying_key)
-    } else {
-        Err(Report::msg("No proving/verification key found!"))
-    }
-}
-
-// Loads the verification key
-#[cfg(not(target_arch = "wasm32"))]
-pub fn vk_from_folder() -> Result<VerifyingKey<Curve>> {
-    let vk = RESOURCES_DIR.get_file(Path::new(VK_FILENAME));
-    let zkey = RESOURCES_DIR.get_file(Path::new(ZKEY_FILENAME));
-
-    let verifying_key: VerifyingKey<Curve>;
-    if let Some(vk) = vk {
-        verifying_key = vk_from_json(vk.contents_utf8().ok_or(Report::msg(
-            "Could not read verification key from JSON file!",
-        ))?)?;
-        Ok(verifying_key)
-    } else if let Some(_zkey) = zkey {
-        let (proving_key, _matrices) = zkey_from_folder()?;
-        verifying_key = proving_key.vk;
-        Ok(verifying_key)
-    } else {
-        Err(Report::msg("No proving/verification key found!"))
-    }
-}
-
-#[cfg(not(target_arch = "wasm32"))]
-static WITNESS_CALCULATOR: OnceCell<Mutex<WitnessCalculator>> = OnceCell::new();
-
-// Initializes the witness calculator using a bytes vector
-#[cfg(not(target_arch = "wasm32"))]
-pub fn circom_from_raw(wasm_buffer: Vec<u8>) -> Result<&'static Mutex<WitnessCalculator>> {
-    WITNESS_CALCULATOR.get_or_try_init(|| {
-        let store = Store::default();
-        let module = Module::new(&store, wasm_buffer)?;
-        let result = WitnessCalculator::from_module(module)?;
-        Ok::<Mutex<WitnessCalculator>, Report>(Mutex::new(result))
-    })
-}
-
-// Initializes the witness calculator
-#[cfg(not(target_arch = "wasm32"))]
-pub fn circom_from_folder() -> Result<&'static Mutex<WitnessCalculator>> {
-    // We read the wasm file
-    let wasm = RESOURCES_DIR.get_file(Path::new(WASM_FILENAME));
-
-    if let Some(wasm) = wasm {
-        let wasm_buffer = wasm.contents();
-        circom_from_raw(wasm_buffer.to_vec())
-    } else {
-        Err(Report::msg("No wasm file found!"))
-    }
-}
-
-// 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) -> Result<Fq> {
-    Ok(Fq::from(BigUint::from_str(s)?))
-}
-
-// Extracts the element in G1 corresponding to its JSON serialization
-fn json_to_g1(json: &Value, key: &str) -> Result<G1Affine> {
-    let els: Vec<String> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| i.as_str().ok_or(Report::msg("element is not a string")))
-        .map(|x| x.map(|v| v.to_owned()))
-        .collect::<Result<Vec<String>>>()?;
-
-    Ok(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) -> Result<Vec<G1Affine>> {
-    let els: Vec<Vec<String>> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| {
-            i.as_array()
-                .ok_or(Report::msg("element is not an array"))
-                .and_then(|array| {
-                    array
-                        .iter()
-                        .map(|x| x.as_str().ok_or(Report::msg("element is not a string")))
-                        .map(|x| x.map(|v| v.to_owned()))
-                        .collect::<Result<Vec<String>>>()
-                })
-        })
-        .collect::<Result<Vec<Vec<String>>>>()?;
-
-    let mut res = vec![];
-    for coords in els {
-        res.push(G1Affine::from(G1Projective::new(
-            fq_from_str(&coords[0])?,
-            fq_from_str(&coords[1])?,
-            fq_from_str(&coords[2])?,
-        )))
+        return Ok(proving_key.vk);
     }
 
-    Ok(res)
-}
-
-// Extracts the element in G2 corresponding to its JSON serialization
-fn json_to_g2(json: &Value, key: &str) -> Result<G2Affine> {
-    let els: Vec<Vec<String>> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| {
-            i.as_array()
-                .ok_or(Report::msg("element is not an array"))
-                .and_then(|array| {
-                    array
-                        .iter()
-                        .map(|x| x.as_str().ok_or(Report::msg("element is not a string")))
-                        .map(|x| x.map(|v| v.to_owned()))
-                        .collect::<Result<Vec<String>>>()
-                })
-        })
-        .collect::<Result<Vec<Vec<String>>>>()?;
-
-    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])?);
-    Ok(G2Affine::from(G2Projective::new(x, y, z)))
-}
-
-// Converts JSON to a VerifyingKey
-fn to_verifying_key(json: serde_json::Value) -> Result<VerifyingKey<Curve>> {
-    Ok(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: &str) -> Result<VerifyingKey<Curve>> {
-    let json: Value = serde_json::from_str(vk)?;
-    to_verifying_key(json)
-}
-
-// Computes the verification key from a bytes vector containing its JSON serialization
-fn vk_from_vector(vk: &[u8]) -> Result<VerifyingKey<Curve>> {
-    let json = String::from_utf8(vk.to_vec())?;
-    let json: Value = serde_json::from_str(&json)?;
-
-    to_verifying_key(json)
+    Err(Report::msg("No proving/verification key found!"))
 }
 
 // Checks verification key to be correct with respect to proving key
-#[cfg(not(target_arch = "wasm32"))]
 pub fn check_vk_from_zkey(verifying_key: VerifyingKey<Curve>) -> Result<()> {
-    let (proving_key, _matrices) = zkey_from_folder()?;
+    let (proving_key, _matrices) = zkey_from_folder();
     if proving_key.vk == verifying_key {
         Ok(())
     } else {
         Err(Report::msg("verifying_keys are not equal"))
     }
 }
+
+pub fn calculate_rln_witness<I: IntoIterator<Item = (String, Vec<Fr>)>>(
+    inputs: I,
+    graph_data: &[u8],
+) -> Vec<Fr> {
+    calc_witness(inputs, graph_data)
+}
+
+pub fn 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
+////////////////////////////////////////////////////////
+
+#[cfg(feature = "arkzkey")]
+#[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
+pub struct SerializableProvingKey(pub ProvingKey<Bn254>);
+
+#[cfg(feature = "arkzkey")]
+#[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
+pub struct SerializableConstraintMatrices<F: Field> {
+    pub num_instance_variables: usize,
+    pub num_witness_variables: usize,
+    pub num_constraints: usize,
+    pub a_num_non_zero: usize,
+    pub b_num_non_zero: usize,
+    pub c_num_non_zero: usize,
+    pub a: SerializableMatrix<F>,
+    pub b: SerializableMatrix<F>,
+    pub c: SerializableMatrix<F>,
+}
+
+#[cfg(feature = "arkzkey")]
+#[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
+pub struct SerializableMatrix<F: Field> {
+    pub data: Vec<Vec<(F, usize)>>,
+}
+
+#[cfg(feature = "arkzkey")]
+pub fn read_arkzkey_from_bytes_uncompressed(
+    arkzkey_data: &[u8],
+) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
+    if arkzkey_data.is_empty() {
+        return Err(Report::msg("No proving key found!"));
+    }
+
+    let mut cursor = std::io::Cursor::new(arkzkey_data);
+
+    let serialized_proving_key =
+        SerializableProvingKey::deserialize_uncompressed_unchecked(&mut cursor)
+            .wrap_err("Failed to deserialize proving key")?;
+
+    let serialized_constraint_matrices =
+        SerializableConstraintMatrices::deserialize_uncompressed_unchecked(&mut cursor)
+            .wrap_err("Failed to deserialize constraint matrices")?;
+
+    // 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/ffi.rs

@@ -8,6 +8,7 @@ use crate::public::{hash as public_hash, poseidon_hash as public_poseidon_hash,
 // First argument to the macro is context,
 // second is the actual method on `RLN`
 // rest are all other arguments to the method
+#[cfg(not(feature = "stateless"))]
 macro_rules! call {
     ($instance:expr, $method:ident $(, $arg:expr)*) => {
         {
@@ -143,24 +144,24 @@ impl ProcessArg for *const Buffer {
     }
 }
 
-impl<'a> ProcessArg for *const RLN<'a> {
-    type ReturnType = &'a RLN<'a>;
+impl ProcessArg for *const RLN {
+    type ReturnType = &'static RLN;
     fn process(self) -> Self::ReturnType {
         unsafe { &*self }
     }
 }
 
-impl<'a> ProcessArg for *mut RLN<'a> {
-    type ReturnType = &'a mut RLN<'a>;
+impl ProcessArg for *mut RLN {
+    type ReturnType = &'static mut RLN;
     fn process(self) -> Self::ReturnType {
         unsafe { &mut *self }
     }
 }
 
-/// Buffer struct is taken from
-/// <https://github.com/celo-org/celo-threshold-bls-rs/blob/master/crates/threshold-bls-ffi/src/ffi.rs>
-///
-/// Also heavily inspired by <https://github.com/kilic/rln/blob/master/src/ffi.rs>
+///// 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)]
@@ -192,6 +193,7 @@ impl<'a> From<&Buffer> for &'a [u8] {
 ////////////////////////////////////////////////////////
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(not(feature = "stateless"))]
 #[no_mangle]
 pub extern "C" fn new(tree_height: usize, input_buffer: *const Buffer, ctx: *mut *mut RLN) -> bool {
     match RLN::new(tree_height, input_buffer.process()) {
@@ -207,20 +209,35 @@ pub extern "C" fn new(tree_height: usize, input_buffer: *const Buffer, ctx: *mut
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(feature = "stateless")]
+#[no_mangle]
+pub extern "C" fn new(ctx: *mut *mut RLN) -> bool {
+    match RLN::new() {
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
+    }
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(not(feature = "stateless"))]
 #[no_mangle]
 pub extern "C" fn new_with_params(
     tree_height: usize,
-    circom_buffer: *const Buffer,
     zkey_buffer: *const Buffer,
-    vk_buffer: *const Buffer,
+    graph_data: *const Buffer,
     tree_config: *const Buffer,
     ctx: *mut *mut RLN,
 ) -> bool {
     match RLN::new_with_params(
         tree_height,
-        circom_buffer.process().to_vec(),
         zkey_buffer.process().to_vec(),
-        vk_buffer.process().to_vec(),
+        graph_data.process().to_vec(),
         tree_config.process(),
     ) {
         Ok(rln) => {
@@ -234,47 +251,77 @@ pub extern "C" fn new_with_params(
     }
 }
 
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(feature = "stateless")]
+#[no_mangle]
+pub extern "C" fn new_with_params(
+    zkey_buffer: *const Buffer,
+    graph_buffer: *const Buffer,
+    ctx: *mut *mut RLN,
+) -> bool {
+    match RLN::new_with_params(
+        zkey_buffer.process().to_vec(),
+        graph_buffer.process().to_vec(),
+    ) {
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
+    }
+}
+
 ////////////////////////////////////////////////////////
 // Merkle tree APIs
 ////////////////////////////////////////////////////////
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_tree(ctx: *mut RLN, tree_height: usize) -> bool {
     call!(ctx, set_tree, tree_height)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn delete_leaf(ctx: *mut RLN, index: usize) -> bool {
     call!(ctx, delete_leaf, index)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_leaf(ctx: *mut RLN, index: usize, input_buffer: *const Buffer) -> bool {
     call!(ctx, set_leaf, index, input_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_leaf(ctx: *mut RLN, index: usize, output_buffer: *mut Buffer) -> bool {
     call_with_output_arg!(ctx, get_leaf, output_buffer, index)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn leaves_set(ctx: *mut RLN) -> usize {
     ctx.process().leaves_set()
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_next_leaf(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
     call!(ctx, set_next_leaf, input_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_leaves_from(
     ctx: *mut RLN,
     index: usize,
@@ -285,12 +332,14 @@ pub extern "C" fn set_leaves_from(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn init_tree_with_leaves(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
     call!(ctx, init_tree_with_leaves, input_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn atomic_operation(
     ctx: *mut RLN,
     index: usize,
@@ -302,6 +351,7 @@ pub extern "C" fn atomic_operation(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn seq_atomic_operation(
     ctx: *mut RLN,
     leaves_buffer: *const Buffer,
@@ -318,12 +368,14 @@ pub extern "C" fn seq_atomic_operation(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_root(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
     call_with_output_arg!(ctx, get_root, output_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_proof(ctx: *const RLN, index: usize, output_buffer: *mut Buffer) -> bool {
     call_with_output_arg!(ctx, get_proof, output_buffer, index)
 }
@@ -353,6 +405,7 @@ pub extern "C" fn verify(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn generate_rln_proof(
     ctx: *mut RLN,
     input_buffer: *const Buffer,
@@ -378,6 +431,7 @@ pub extern "C" fn generate_rln_proof_with_witness(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn verify_rln_proof(
     ctx: *const RLN,
     proof_buffer: *const Buffer,
@@ -461,18 +515,21 @@ pub extern "C" fn recover_id_secret(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_metadata(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
     call!(ctx, set_metadata, input_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_metadata(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
     call_with_output_arg!(ctx, get_metadata, output_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn flush(ctx: *mut RLN) -> bool {
     call!(ctx, flush)
 }

rln/src/iden3calc.rs

@@ -0,0 +1,73 @@
+// 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 crate::circuit::Fr;
+use graph::{fr_to_u256, Node};
+
+pub type InputSignalsInfo = HashMap<String, (usize, usize)>;
+
+pub fn calc_witness<I: IntoIterator<Item = (String, Vec<Fr>)>>(
+    inputs: I,
+    graph_data: &[u8],
+) -> Vec<Fr> {
+    let inputs: HashMap<String, Vec<U256>> = inputs
+        .into_iter()
+        .map(|(key, value)| (key, value.iter().map(fr_to_u256).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);
+
+    graph::evaluate(&nodes, inputs_buffer.as_slice(), &signals)
+}
+
+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/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::{BitAnd, BitOr, BitXor, Deref, Shl, Shr},
+};
+
+use crate::circuit::Fr;
+use crate::iden3calc::proto;
+
+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.get(0);
+        println!("{:?}", node);
+    }
+}

rln/src/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/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::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(buf).unwrap();
+        assert_eq!(buf, &[1, 2, 3, 4, 5]);
+
+        // return [4, 5] to reader
+        r.write(&buf[3..]).unwrap();
+        // return [2, 3] to reader
+        r.write(&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/lib.rs

@@ -2,6 +2,7 @@
 
 pub mod circuit;
 pub mod hashers;
+pub mod iden3calc;
 #[cfg(feature = "pmtree-ft")]
 pub mod pm_tree_adapter;
 pub mod poseidon_tree;
@@ -11,5 +12,4 @@ pub mod public;
 pub mod public_api_tests;
 pub mod utils;
 
-#[cfg(not(target_arch = "wasm32"))]
 pub mod ffi;

rln/src/protocol.rs

@@ -1,9 +1,9 @@
 // This crate collects all the underlying primitives used to implement RLN
 
-use ark_circom::{CircomReduction, WitnessCalculator};
+use ark_bn254::Fr;
+use ark_circom::CircomReduction;
 use ark_groth16::{prepare_verifying_key, Groth16, Proof as ArkProof, ProvingKey, VerifyingKey};
-use ark_relations::r1cs::ConstraintMatrices;
-use ark_relations::r1cs::SynthesisError;
+use ark_relations::r1cs::{ConstraintMatrices, SynthesisError};
 use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
 use ark_std::{rand::thread_rng, UniformRand};
 use color_eyre::{Report, Result};
@@ -11,20 +11,16 @@ use num_bigint::BigInt;
 use rand::{Rng, SeedableRng};
 use rand_chacha::ChaCha20Rng;
 use serde::{Deserialize, Serialize};
-#[cfg(not(target_arch = "wasm32"))]
-use std::sync::Mutex;
-#[cfg(debug_assertions)]
+#[cfg(test)]
 use std::time::Instant;
 use thiserror::Error;
 use tiny_keccak::{Hasher as _, Keccak};
 
-use crate::circuit::{Curve, Fr};
-use crate::hashers::hash_to_field;
-use crate::hashers::poseidon_hash;
+use crate::circuit::{calculate_rln_witness, Curve};
+use crate::hashers::{hash_to_field, poseidon_hash};
 use crate::poseidon_tree::*;
 use crate::public::RLN_IDENTIFIER;
 use crate::utils::*;
-use cfg_if::cfg_if;
 use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
 
 ///////////////////////////////////////////////////////
@@ -103,18 +99,26 @@ pub fn deserialize_identity_tuple(serialized: Vec<u8>) -> (Fr, Fr, Fr, Fr) {
 /// # Errors
 ///
 /// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
+/// input data is [ identity_secret<32> | user_message_limit<32> | message_id<32> | path_elements[<32>] | identity_path_index<8> | x<32> | external_nullifier<32> ]
 pub fn serialize_witness(rln_witness: &RLNWitnessInput) -> Result<Vec<u8>> {
+    // Check if message_id is within user_message_limit
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
 
-    let mut serialized: Vec<u8> = Vec::new();
-
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.identity_secret));
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.user_message_limit));
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.message_id));
-    serialized.append(&mut vec_fr_to_bytes_le(&rln_witness.path_elements)?);
-    serialized.append(&mut vec_u8_to_bytes_le(&rln_witness.identity_path_index)?);
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.x));
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.external_nullifier));
+    // Calculate capacity for Vec:
+    // - 5 fixed field elements: identity_secret, user_message_limit, message_id, x, external_nullifier
+    // - variable number of path elements
+    // - identity_path_index (variable size)
+    let mut serialized: Vec<u8> = Vec::with_capacity(
+        fr_byte_size() * (5 + rln_witness.path_elements.len())
+            + rln_witness.identity_path_index.len(),
+    );
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.identity_secret));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.user_message_limit));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.message_id));
+    serialized.extend_from_slice(&vec_fr_to_bytes_le(&rln_witness.path_elements)?);
+    serialized.extend_from_slice(&vec_u8_to_bytes_le(&rln_witness.identity_path_index)?);
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.x));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.external_nullifier));
 
     Ok(serialized)
 }
@@ -222,7 +226,7 @@ pub fn proof_inputs_to_rln_witness(
     ))
 }
 
-/// Creates `RLNWitnessInput` from it's fields.
+/// Creates [`RLNWitnessInput`] from it's fields.
 ///
 /// # Errors
 ///
@@ -309,14 +313,17 @@ pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> Result<RLNPro
     })
 }
 
+/// input_data is [ root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
 pub fn serialize_proof_values(rln_proof_values: &RLNProofValues) -> Vec<u8> {
-    let mut serialized: Vec<u8> = Vec::new();
+    // Calculate capacity for Vec:
+    // 5 field elements: root, external_nullifier, x, y, nullifier
+    let mut serialized = Vec::with_capacity(fr_byte_size() * 5);
 
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.root));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.external_nullifier));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.x));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.y));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.nullifier));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.root));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.external_nullifier));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.x));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.y));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.nullifier));
 
     serialized
 }
@@ -353,30 +360,43 @@ pub fn deserialize_proof_values(serialized: &[u8]) -> (RLNProofValues, usize) {
     )
 }
 
+// input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
 pub fn prepare_prove_input(
     identity_secret: Fr,
     id_index: usize,
+    user_message_limit: Fr,
+    message_id: Fr,
     external_nullifier: Fr,
     signal: &[u8],
 ) -> Vec<u8> {
-    let mut serialized: Vec<u8> = Vec::new();
+    // Calculate capacity for Vec:
+    // - 4 field elements: identity_secret, user_message_limit, message_id, external_nullifier
+    // - 16 bytes for two normalized usize values (id_index<8> + signal_len<8>)
+    // - variable length signal data
+    let mut serialized = Vec::with_capacity(fr_byte_size() * 4 + 16 + signal.len()); // length of 4 fr elements + 16 bytes (id_index + len) + signal length
 
-    serialized.append(&mut fr_to_bytes_le(&identity_secret));
-    serialized.append(&mut normalize_usize(id_index));
-    serialized.append(&mut fr_to_bytes_le(&external_nullifier));
-    serialized.append(&mut normalize_usize(signal.len()));
-    serialized.append(&mut signal.to_vec());
+    serialized.extend_from_slice(&fr_to_bytes_le(&identity_secret));
+    serialized.extend_from_slice(&normalize_usize(id_index));
+    serialized.extend_from_slice(&fr_to_bytes_le(&user_message_limit));
+    serialized.extend_from_slice(&fr_to_bytes_le(&message_id));
+    serialized.extend_from_slice(&fr_to_bytes_le(&external_nullifier));
+    serialized.extend_from_slice(&normalize_usize(signal.len()));
+    serialized.extend_from_slice(signal);
 
     serialized
 }
 
-#[allow(clippy::redundant_clone)]
+// input_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
 pub fn prepare_verify_input(proof_data: Vec<u8>, signal: &[u8]) -> Vec<u8> {
-    let mut serialized: Vec<u8> = Vec::new();
+    // Calculate capacity for Vec:
+    // - proof_data contains the proof and proof values (proof<128> + root<32> + external_nullifier<32> + x<32> + y<32> + nullifier<32>)
+    // - 8 bytes for normalized signal length value (signal_len<8>)
+    // - variable length signal data
+    let mut serialized = Vec::with_capacity(proof_data.len() + 8 + signal.len());
 
-    serialized.append(&mut proof_data.clone());
-    serialized.append(&mut normalize_usize(signal.len()));
-    serialized.append(&mut signal.to_vec());
+    serialized.extend(proof_data);
+    serialized.extend_from_slice(&normalize_usize(signal.len()));
+    serialized.extend_from_slice(signal);
 
     serialized
 }
@@ -544,13 +564,13 @@ pub fn generate_proof_with_witness(
     proving_key: &(ProvingKey<Curve>, ConstraintMatrices<Fr>),
 ) -> Result<ArkProof<Curve>, ProofError> {
     // If in debug mode, we measure and later print time take to compute witness
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
 
     let full_assignment =
         calculate_witness_element::<Curve>(witness).map_err(ProofError::WitnessError)?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("witness generation took: {:.2?}", now.elapsed());
 
     // Random Values
@@ -559,7 +579,7 @@ pub fn generate_proof_with_witness(
     let s = Fr::rand(&mut rng);
 
     // If in debug mode, we measure and later print time take to compute proof
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
 
     let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
@@ -572,7 +592,7 @@ pub fn generate_proof_with_witness(
         full_assignment.as_slice(),
     )?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("proof generation took: {:.2?}", now.elapsed());
 
     Ok(proof)
@@ -585,40 +605,23 @@ pub fn generate_proof_with_witness(
 /// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
 pub fn inputs_for_witness_calculation(
     rln_witness: &RLNWitnessInput,
-) -> Result<[(&str, Vec<BigInt>); 7]> {
+) -> Result<[(&str, Vec<Fr>); 7]> {
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
 
-    // We convert the path indexes to field elements
-    // TODO: check if necessary
-    let mut path_elements = Vec::new();
-
-    for v in rln_witness.path_elements.iter() {
-        path_elements.push(to_bigint(v)?);
-    }
-
-    let mut identity_path_index = Vec::new();
+    let mut identity_path_index = Vec::with_capacity(rln_witness.identity_path_index.len());
     rln_witness
         .identity_path_index
         .iter()
-        .for_each(|v| identity_path_index.push(BigInt::from(*v)));
+        .for_each(|v| identity_path_index.push(Fr::from(*v)));
 
     Ok([
-        (
-            "identitySecret",
-            vec![to_bigint(&rln_witness.identity_secret)?],
-        ),
-        (
-            "userMessageLimit",
-            vec![to_bigint(&rln_witness.user_message_limit)?],
-        ),
-        ("messageId", vec![to_bigint(&rln_witness.message_id)?]),
-        ("pathElements", path_elements),
+        ("identitySecret", vec![rln_witness.identity_secret]),
+        ("userMessageLimit", vec![rln_witness.user_message_limit]),
+        ("messageId", vec![rln_witness.message_id]),
+        ("pathElements", rln_witness.path_elements.clone()),
         ("identityPathIndex", identity_path_index),
-        ("x", vec![to_bigint(&rln_witness.x)?]),
-        (
-            "externalNullifier",
-            vec![to_bigint(&rln_witness.external_nullifier)?],
-        ),
+        ("x", vec![rln_witness.x]),
+        ("externalNullifier", vec![rln_witness.external_nullifier]),
     ])
 }
 
@@ -628,34 +631,20 @@ pub fn inputs_for_witness_calculation(
 ///
 /// Returns a [`ProofError`] if proving fails.
 pub fn generate_proof(
-    #[cfg(not(target_arch = "wasm32"))] witness_calculator: &Mutex<WitnessCalculator>,
-    #[cfg(target_arch = "wasm32")] witness_calculator: &mut WitnessCalculator,
     proving_key: &(ProvingKey<Curve>, ConstraintMatrices<Fr>),
     rln_witness: &RLNWitnessInput,
+    graph_data: &[u8],
 ) -> Result<ArkProof<Curve>, ProofError> {
     let inputs = inputs_for_witness_calculation(rln_witness)?
         .into_iter()
         .map(|(name, values)| (name.to_string(), values));
 
     // If in debug mode, we measure and later print time take to compute witness
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
+    let full_assignment = calculate_rln_witness(inputs, graph_data);
 
-    cfg_if! {
-        if #[cfg(target_arch = "wasm32")] {
-            let full_assignment = witness_calculator
-            .calculate_witness_element::<Curve, _>(inputs, false)
-            .map_err(ProofError::WitnessError)?;
-        } else {
-            let full_assignment = witness_calculator
-            .lock()
-            .expect("witness_calculator mutex should not get poisoned")
-            .calculate_witness_element::<Curve, _>(inputs, false)
-            .map_err(ProofError::WitnessError)?;
-        }
-    }
-
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("witness generation took: {:.2?}", now.elapsed());
 
     // Random Values
@@ -664,7 +653,7 @@ pub fn generate_proof(
     let s = Fr::rand(&mut rng);
 
     // If in debug mode, we measure and later print time take to compute proof
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
     let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
         &proving_key.0,
@@ -676,7 +665,7 @@ pub fn generate_proof(
         full_assignment.as_slice(),
     )?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("proof generation took: {:.2?}", now.elapsed());
 
     Ok(proof)
@@ -707,12 +696,12 @@ pub fn verify_proof(
     //let pr: ArkProof<Curve> = (*proof).into();
 
     // If in debug mode, we measure and later print time take to verify proof
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
 
     let verified = Groth16::<_, CircomReduction>::verify_proof(&pvk, proof, &inputs)?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("verify took: {:.2?}", now.elapsed());
 
     Ok(verified)
@@ -739,11 +728,11 @@ where
     a.map_err(serde::de::Error::custom)
 }
 
-/// Converts a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object to the corresponding JSON serialization.
+/// Converts a JSON value into [`RLNWitnessInput`] object.
 ///
 /// # Errors
 ///
-/// Returns an error if `message_id` is not within `user_message_limit`.
+/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
 pub fn rln_witness_from_json(input_json: serde_json::Value) -> Result<RLNWitnessInput> {
     let rln_witness: RLNWitnessInput = serde_json::from_value(input_json).unwrap();
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
@@ -751,11 +740,11 @@ pub fn rln_witness_from_json(input_json: serde_json::Value) -> Result<RLNWitness
     Ok(rln_witness)
 }
 
-/// Converts a JSON value into [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object.
+/// Converts a [`RLNWitnessInput`] object to the corresponding JSON serialization.
 ///
 /// # Errors
 ///
-/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
+/// Returns an error if `message_id` is not within `user_message_limit`.
 pub fn rln_witness_to_json(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
 
@@ -763,6 +752,40 @@ pub fn rln_witness_to_json(rln_witness: &RLNWitnessInput) -> Result<serde_json::
     Ok(rln_witness_json)
 }
 
+/// Converts a [`RLNWitnessInput`] object to the corresponding JSON serialization.
+/// Before serialisation the data should be translated into big int for further calculation in the witness calculator.
+///
+/// # Errors
+///
+/// Returns an error if `message_id` is not within `user_message_limit`.
+pub fn rln_witness_to_bigint_json(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
+
+    let mut path_elements = Vec::new();
+
+    for v in rln_witness.path_elements.iter() {
+        path_elements.push(to_bigint(v)?.to_str_radix(10));
+    }
+
+    let mut identity_path_index = Vec::new();
+    rln_witness
+        .identity_path_index
+        .iter()
+        .for_each(|v| identity_path_index.push(BigInt::from(*v).to_str_radix(10)));
+
+    let inputs = serde_json::json!({
+        "identitySecret": to_bigint(&rln_witness.identity_secret)?.to_str_radix(10),
+        "userMessageLimit": to_bigint(&rln_witness.user_message_limit)?.to_str_radix(10),
+        "messageId": to_bigint(&rln_witness.message_id)?.to_str_radix(10),
+        "pathElements": path_elements,
+        "identityPathIndex": identity_path_index,
+        "x": to_bigint(&rln_witness.x)?.to_str_radix(10),
+        "externalNullifier":  to_bigint(&rln_witness.external_nullifier)?.to_str_radix(10),
+    });
+
+    Ok(inputs)
+}
+
 pub fn message_id_range_check(message_id: &Fr, user_message_limit: &Fr) -> Result<()> {
     if message_id > user_message_limit {
         return Err(color_eyre::Report::msg(

rln/src/public.rs

@@ -1,33 +1,23 @@
-use crate::circuit::{vk_from_raw, zkey_from_raw, Curve, Fr};
+/// This is the main public API for RLN module. It is used by the FFI, and should be
+/// used by tests etc. as well
+#[cfg(not(feature = "stateless"))]
+use {
+    crate::{circuit::TEST_TREE_HEIGHT, poseidon_tree::PoseidonTree},
+    serde_json::{json, Value},
+    std::str::FromStr,
+    utils::{Hasher, ZerokitMerkleProof, ZerokitMerkleTree},
+};
+
+use crate::circuit::{graph_from_folder, vk_from_raw, zkey_from_folder, zkey_from_raw, Curve, Fr};
 use crate::hashers::{hash_to_field, poseidon_hash as utils_poseidon_hash};
-use crate::poseidon_tree::PoseidonTree;
 use crate::protocol::*;
 use crate::utils::*;
-/// This is the main public API for RLN module. It is used by the FFI, and should be
-/// used by tests etc as well
-use ark_groth16::Proof as ArkProof;
-use ark_groth16::{ProvingKey, VerifyingKey};
+
+use ark_groth16::{Proof as ArkProof, ProvingKey, VerifyingKey};
 use ark_relations::r1cs::ConstraintMatrices;
 use ark_serialize::{CanonicalDeserialize, CanonicalSerialize, Read, Write};
-use cfg_if::cfg_if;
 use color_eyre::{Report, Result};
-use std::io::Cursor;
-use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
-
-cfg_if! {
-    if #[cfg(not(target_arch = "wasm32"))] {
-        use std::default::Default;
-        use std::sync::Mutex;
-        use crate::circuit::{circom_from_folder, vk_from_folder, circom_from_raw, zkey_from_folder, TEST_TREE_HEIGHT};
-        use ark_circom::WitnessCalculator;
-        use serde_json::{json, Value};
-        use utils::{Hasher};
-        use std::str::FromStr;
-    } else {
-        use std::marker::*;
-        use num_bigint::BigInt;
-    }
-}
+use std::{default::Default, io::Cursor};
 
 /// The application-specific RLN identifier.
 ///
@@ -39,38 +29,33 @@ pub const RLN_IDENTIFIER: &[u8] = b"zerokit/rln/010203040506070809";
 /// It implements the methods required to update the internal Merkle Tree, generate and verify RLN ZK proofs.
 ///
 /// I/O is mostly done using writers and readers implementing `std::io::Write` and `std::io::Read`, respectively.
-pub struct RLN<'a> {
+pub struct RLN {
     proving_key: (ProvingKey<Curve>, ConstraintMatrices<Fr>),
     pub(crate) verification_key: VerifyingKey<Curve>,
+    pub(crate) graph_data: Vec<u8>,
+    #[cfg(not(feature = "stateless"))]
     pub(crate) tree: PoseidonTree,
-
-    // The witness calculator can't be loaded in zerokit. Since this struct
-    // contains a lifetime, a PhantomData is necessary to avoid a compiler
-    // error since the lifetime is not being used
-    #[cfg(not(target_arch = "wasm32"))]
-    pub(crate) witness_calculator: &'a Mutex<WitnessCalculator>,
-    #[cfg(target_arch = "wasm32")]
-    _marker: PhantomData<&'a ()>,
 }
 
-impl RLN<'_> {
+impl RLN {
     /// Creates a new RLN object by loading circuit resources from a folder.
     ///
     /// Input parameters are
     /// - `tree_height`: the height of the internal Merkle tree
     /// - `input_data`: include `tree_config` a reader for a string containing a json with the merkle tree configuration
+    ///
     /// Example:
     /// ```
     /// use std::io::Cursor;
     ///
     /// let tree_height = 20;
-    /// let input = Cursor::new(json!({}).to_string());;
+    /// let input = Cursor::new(json!({}).to_string());
     ///
     /// // We create a new RLN instance
     /// let mut rln = RLN::new(tree_height, input);
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
-    pub fn new<R: Read>(tree_height: usize, mut input_data: R) -> Result<RLN<'static>> {
+    #[cfg(not(feature = "stateless"))]
+    pub fn new<R: Read>(tree_height: usize, mut input_data: R) -> Result<RLN> {
         // We read input
         let mut input: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut input)?;
@@ -78,10 +63,9 @@ impl RLN<'_> {
         let rln_config: Value = serde_json::from_str(&String::from_utf8(input)?)?;
         let tree_config = rln_config["tree_config"].to_string();
 
-        let witness_calculator = circom_from_folder()?;
-        let proving_key = zkey_from_folder()?;
-
-        let verification_key = vk_from_folder()?;
+        let proving_key = zkey_from_folder();
+        let verification_key = &proving_key.0.vk;
+        let graph_data = graph_from_folder();
 
         let tree_config: <PoseidonTree as ZerokitMerkleTree>::Config = if tree_config.is_empty() {
             <PoseidonTree as ZerokitMerkleTree>::Config::default()
@@ -97,12 +81,33 @@ impl RLN<'_> {
         )?;
 
         Ok(RLN {
-            witness_calculator,
-            proving_key,
-            verification_key,
+            proving_key: proving_key.to_owned(),
+            verification_key: verification_key.to_owned(),
+            graph_data: graph_data.to_vec(),
+            #[cfg(not(feature = "stateless"))]
             tree,
-            #[cfg(target_arch = "wasm32")]
-            _marker: PhantomData,
+        })
+    }
+
+    /// Creates a new stateless RLN object by loading circuit resources from a folder.
+    ///
+    /// Example:
+    ///
+    /// ```
+    /// // We create a new RLN instance
+    /// let mut rln = RLN::new();
+    /// ```
+    #[cfg_attr(docsrs, doc(cfg(feature = "stateless")))]
+    #[cfg(feature = "stateless")]
+    pub fn new() -> Result<RLN> {
+        let proving_key = zkey_from_folder();
+        let verification_key = &proving_key.0.vk;
+        let graph_data = graph_from_folder();
+
+        Ok(RLN {
+            proving_key: proving_key.to_owned(),
+            verification_key: verification_key.to_owned(),
+            graph_data: graph_data.to_vec(),
         })
     }
 
@@ -110,9 +115,7 @@ impl RLN<'_> {
     ///
     /// Input parameters are
     /// - `tree_height`: the height of the internal Merkle tree
-    /// - `circom_vec`: a byte vector containing the ZK circuit (`rln.wasm`) as binary file
     /// - `zkey_vec`: a byte vector containing to the proving key (`rln_final.zkey`)  or (`rln_final.arkzkey`) as binary file
-    /// - `vk_vec`: a byte vector containing to the verification key (`verification_key.json`) as binary file
     /// - `tree_config_input`: a reader for a string containing a json with the merkle tree configuration
     ///
     /// Example:
@@ -124,38 +127,35 @@ impl RLN<'_> {
     /// let resources_folder = "./resources/tree_height_20/";
     ///
     /// let mut resources: Vec<Vec<u8>> = Vec::new();
-    /// for filename in ["rln.wasm", "rln_final.zkey", "verification_key.json"] {
+    /// for filename in ["rln_final.zkey", "graph.bin"] {
     ///     let fullpath = format!("{resources_folder}{filename}");
     ///     let mut file = File::open(&fullpath).expect("no file found");
     ///     let metadata = std::fs::metadata(&fullpath).expect("unable to read metadata");
     ///     let mut buffer = vec![0; metadata.len() as usize];
     ///     file.read_exact(&mut buffer).expect("buffer overflow");
     ///     resources.push(buffer);
-    ///     let tree_config = "{}".to_string();
-    ///     let tree_config_input = &Buffer::from(tree_config.as_bytes());
     /// }
     ///
+    /// let tree_config = "".to_string();
+    /// let tree_config_buffer = &Buffer::from(tree_config.as_bytes());
+    ///
     /// let mut rln = RLN::new_with_params(
     ///     tree_height,
     ///     resources[0].clone(),
     ///     resources[1].clone(),
     ///     resources[2].clone(),
-    ///     tree_config_input,
+    ///     tree_config_buffer,
     /// );
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
+    #[cfg(not(feature = "stateless"))]
     pub fn new_with_params<R: Read>(
         tree_height: usize,
-        circom_vec: Vec<u8>,
         zkey_vec: Vec<u8>,
-        vk_vec: Vec<u8>,
+        graph_data: Vec<u8>,
         mut tree_config_input: R,
-    ) -> Result<RLN<'static>> {
-        #[cfg(not(target_arch = "wasm32"))]
-        let witness_calculator = circom_from_raw(circom_vec)?;
-
+    ) -> Result<RLN> {
         let proving_key = zkey_from_raw(&zkey_vec)?;
-        let verification_key = vk_from_raw(&vk_vec, &zkey_vec)?;
+        let verification_key = vk_from_raw(&zkey_vec)?;
 
         let mut tree_config_vec: Vec<u8> = Vec::new();
         tree_config_input.read_to_end(&mut tree_config_vec)?;
@@ -175,33 +175,51 @@ impl RLN<'_> {
         )?;
 
         Ok(RLN {
-            witness_calculator,
             proving_key,
             verification_key,
+            graph_data,
+            #[cfg(not(feature = "stateless"))]
             tree,
         })
     }
 
-    #[cfg(target_arch = "wasm32")]
-    pub fn new_with_params(
-        tree_height: usize,
-        zkey_vec: Vec<u8>,
-        vk_vec: Vec<u8>,
-    ) -> Result<RLN<'static>> {
-        #[cfg(not(target_arch = "wasm32"))]
-        let witness_calculator = circom_from_raw(circom_vec)?;
-
+    /// Creates a new stateless RLN object by passing circuit resources as byte vectors.
+    ///
+    /// Input parameters are
+    /// - `zkey_vec`: a byte vector containing to the proving key (`rln_final.zkey`)  or (`rln_final.arkzkey`) as binary file
+    ///
+    /// Example:
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::Read;
+    ///
+    /// let resources_folder = "./resources/tree_height_20/";
+    ///
+    /// let mut resources: Vec<Vec<u8>> = Vec::new();
+    /// for filename in ["rln_final.zkey", "graph.bin"] {
+    ///     let fullpath = format!("{resources_folder}{filename}");
+    ///     let mut file = File::open(&fullpath).expect("no file found");
+    ///     let metadata = std::fs::metadata(&fullpath).expect("unable to read metadata");
+    ///     let mut buffer = vec![0; metadata.len() as usize];
+    ///     file.read_exact(&mut buffer).expect("buffer overflow");
+    ///     resources.push(buffer);
+    /// }
+    ///
+    /// let mut rln = RLN::new_with_params(
+    ///     resources[0].clone(),
+    ///     resources[1].clone(),
+    ///     resources[2].clone(),
+    /// );
+    /// ```
+    #[cfg(feature = "stateless")]
+    pub fn new_with_params(zkey_vec: Vec<u8>, graph_data: Vec<u8>) -> Result<RLN> {
         let proving_key = zkey_from_raw(&zkey_vec)?;
-        let verification_key = vk_from_raw(&vk_vec, &zkey_vec)?;
-
-        // We compute a default empty tree
-        let tree = PoseidonTree::default(tree_height)?;
+        let verification_key = vk_from_raw(&zkey_vec)?;
 
         Ok(RLN {
             proving_key,
             verification_key,
-            tree,
-            _marker: PhantomData,
+            graph_data,
         })
     }
 
@@ -214,6 +232,7 @@ impl RLN<'_> {
     ///
     /// Input values are:
     /// - `tree_height`: the height of the Merkle tree.
+    #[cfg(not(feature = "stateless"))]
     pub fn set_tree(&mut self, tree_height: usize) -> Result<()> {
         // We compute a default empty tree of desired height
         self.tree = PoseidonTree::default(tree_height)?;
@@ -244,6 +263,7 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(serialize_field_element(rate_commitment));
     /// rln.set_leaf(id_index, &mut buffer).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn set_leaf<R: Read>(&mut self, index: usize, mut input_data: R) -> Result<()> {
         // We read input
         let mut leaf_byte: Vec<u8> = Vec::new();
@@ -273,6 +293,7 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(Vec::<u8>::new());
     /// rln.get_leaf(id_index, &mut buffer).unwrap();
     /// let rate_commitment = deserialize_field_element(&buffer.into_inner()).unwrap();
+    #[cfg(not(feature = "stateless"))]
     pub fn get_leaf<W: Write>(&self, index: usize, mut output_data: W) -> Result<()> {
         // We get the leaf at input index
         let leaf = self.tree.get(index)?;
@@ -315,6 +336,7 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
     /// rln.set_leaves_from(index, &mut buffer).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn set_leaves_from<R: Read>(&mut self, index: usize, mut input_data: R) -> Result<()> {
         // We read input
         let mut leaves_byte: Vec<u8> = Vec::new();
@@ -335,6 +357,7 @@ impl RLN<'_> {
     ///
     /// Input values are:
     /// - `input_data`: a reader for the serialization of multiple leaf values (serialization done with [`rln::utils::vec_fr_to_bytes_le`](crate::utils::vec_fr_to_bytes_le))
+    #[cfg(not(feature = "stateless"))]
     pub fn init_tree_with_leaves<R: Read>(&mut self, input_data: R) -> Result<()> {
         // reset the tree
         // NOTE: this requires the tree to be initialized with the correct height initially
@@ -385,6 +408,7 @@ impl RLN<'_> {
     /// let mut indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices));
     /// rln.atomic_operation(index, &mut leaves_buffer, indices_buffer).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn atomic_operation<R: Read>(
         &mut self,
         index: usize,
@@ -410,6 +434,7 @@ impl RLN<'_> {
         Ok(())
     }
 
+    #[cfg(not(feature = "stateless"))]
     pub fn leaves_set(&mut self) -> usize {
         self.tree.leaves_set()
     }
@@ -457,6 +482,7 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
     /// rln.set_next_leaf(&mut buffer).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn set_next_leaf<R: Read>(&mut self, mut input_data: R) -> Result<()> {
         // We read input
         let mut leaf_byte: Vec<u8> = Vec::new();
@@ -469,7 +495,7 @@ impl RLN<'_> {
         Ok(())
     }
 
-    /// Sets the value of the leaf at position index to the harcoded default value.
+    /// Sets the value of the leaf at position index to the hardcoded default value.
     ///
     /// This function does not change the internal Merkle tree `next_index` value.
     ///
@@ -482,6 +508,7 @@ impl RLN<'_> {
     /// let index = 10;
     /// rln.delete_leaf(index).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn delete_leaf(&mut self, index: usize) -> Result<()> {
         self.tree.delete(index)?;
         Ok(())
@@ -499,6 +526,7 @@ impl RLN<'_> {
     /// let metadata = b"some metadata";
     /// rln.set_metadata(metadata).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn set_metadata(&mut self, metadata: &[u8]) -> Result<()> {
         self.tree.set_metadata(metadata)?;
         Ok(())
@@ -518,6 +546,7 @@ impl RLN<'_> {
     /// rln.get_metadata(&mut buffer).unwrap();
     /// let metadata = buffer.into_inner();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn get_metadata<W: Write>(&self, mut output_data: W) -> Result<()> {
         let metadata = self.tree.metadata()?;
         output_data.write_all(&metadata)?;
@@ -537,6 +566,7 @@ impl RLN<'_> {
     /// rln.get_root(&mut buffer).unwrap();
     /// let (root, _) = bytes_le_to_fr(&buffer.into_inner());
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn get_root<W: Write>(&self, mut output_data: W) -> Result<()> {
         let root = self.tree.root();
         output_data.write_all(&fr_to_bytes_le(&root))?;
@@ -559,6 +589,7 @@ impl RLN<'_> {
     /// rln.get_subtree_root(level, index, &mut buffer).unwrap();
     /// let (subroot, _) = bytes_le_to_fr(&buffer.into_inner());
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn get_subtree_root<W: Write>(
         &self,
         level: usize,
@@ -592,6 +623,7 @@ impl RLN<'_> {
     /// let (path_elements, read) = bytes_le_to_vec_fr(&buffer_inner);
     /// let (identity_path_index, _) = bytes_le_to_vec_u8(&buffer_inner[read..].to_vec());
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn get_proof<W: Write>(&self, index: usize, mut output_data: W) -> Result<()> {
         let merkle_proof = self.tree.proof(index).expect("proof should exist");
         let path_elements = merkle_proof.get_path_elements();
@@ -635,6 +667,7 @@ impl RLN<'_> {
     /// let idxs = bytes_le_to_vec_usize(&buffer.into_inner()).unwrap();
     /// assert_eq!(idxs, [0, 1, 2, 3, 4]);
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn get_empty_leaves_indices<W: Write>(&self, mut output_data: W) -> Result<()> {
         let idxs = self.tree.get_empty_leaves_indices();
         idxs.serialize_compressed(&mut output_data)?;
@@ -644,10 +677,10 @@ impl RLN<'_> {
     ////////////////////////////////////////////////////////
     // zkSNARK APIs
     ////////////////////////////////////////////////////////
-    /// Computes a zkSNARK RLN proof using a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput).
+    /// Computes a zkSNARK RLN proof using a [`RLNWitnessInput`].
     ///
     /// Input values are:
-    /// - `input_data`: a reader for the serialization of a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object, containing the public and private inputs to the ZK circuits (serialization done using [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness))
+    /// - `input_data`: a reader for the serialization of a [`RLNWitnessInput`] object, containing the public and private inputs to the ZK circuits (serialization done using [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness))
     ///
     /// Output values are:
     /// - `output_data`: a writer receiving the serialization of the zkSNARK proof
@@ -665,7 +698,6 @@ impl RLN<'_> {
     /// rln.prove(&mut input_buffer, &mut output_buffer).unwrap();
     /// let zk_proof = output_buffer.into_inner();
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
     pub fn prove<R: Read, W: Write>(
         &mut self,
         mut input_data: R,
@@ -676,13 +708,7 @@ impl RLN<'_> {
         input_data.read_to_end(&mut serialized)?;
         let (rln_witness, _) = deserialize_witness(&serialized)?;
 
-        /*
-        if self.witness_calculator.is_none() {
-            self.witness_calculator = CIRCOM(&self.resources_folder);
-        }
-        */
-
-        let proof = generate_proof(self.witness_calculator, &self.proving_key, &rln_witness)?;
+        let proof = generate_proof(&self.proving_key, &rln_witness, &self.graph_data)?;
 
         // Note: we export a serialization of ark-groth16::Proof not semaphore::Proof
         proof.serialize_compressed(&mut output_data)?;
@@ -694,7 +720,7 @@ impl RLN<'_> {
     ///
     /// Input values are:
     /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values,
-    ///  i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]`, where <_> indicates the byte length.
+    ///   i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]`, where <_> indicates the byte length.
     ///
     /// The function returns true if the zkSNARK proof is valid with respect to the provided circuit output values, false otherwise.
     ///
@@ -764,26 +790,25 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
     /// rln.set_leaf(identity_index, &mut buffer).unwrap();
     ///
-    /// // We generate a random signal
-    /// let mut rng = rand::thread_rng();
-    /// let signal: [u8; 32] = rng.gen();
-    ///
     /// // We generate a random epoch
     /// let epoch = hash_to_field(b"test-epoch");
     /// // We generate a random rln_identifier
     /// let rln_identifier = hash_to_field(b"test-rln-identifier");
-    /// let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+    /// // We generate a external nullifier
+    /// let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
+    /// // We choose a message_id satisfy 0 <= message_id < MESSAGE_LIMIT
+    /// let message_id = Fr::from(1);
     ///
     /// // We prepare input for generate_rln_proof API
     /// // input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
-    /// let mut serialized: Vec<u8> = Vec::new();
-    /// serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
-    /// serialized.append(&mut normalize_usize(identity_index));
-    /// serialized.append(&mut fr_to_bytes_le(&user_message_limit));
-    /// serialized.append(&mut fr_to_bytes_le(&Fr::from(1))); // message_id
-    /// serialized.append(&mut fr_to_bytes_le(&external_nullifier));
-    /// serialized.append(&mut normalize_usize(signal_len).resize(8,0));
-    /// serialized.append(&mut signal.to_vec());
+    /// let prove_input = prepare_prove_input(
+    ///     identity_secret_hash,
+    ///     identity_index,
+    ///     user_message_limit,
+    ///     message_id,
+    ///     external_nullifier,
+    ///     &signal,
+    /// );
     ///
     /// let mut input_buffer = Cursor::new(serialized);
     /// let mut output_buffer = Cursor::new(Vec::<u8>::new());
@@ -793,7 +818,7 @@ impl RLN<'_> {
     /// // proof_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]
     /// let mut proof_data = output_buffer.into_inner();
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
+    #[cfg(not(feature = "stateless"))]
     pub fn generate_rln_proof<R: Read, W: Write>(
         &mut self,
         mut input_data: R,
@@ -805,7 +830,7 @@ impl RLN<'_> {
         let (rln_witness, _) = proof_inputs_to_rln_witness(&mut self.tree, &witness_byte)?;
         let proof_values = proof_values_from_witness(&rln_witness)?;
 
-        let proof = generate_proof(self.witness_calculator, &self.proving_key, &rln_witness)?;
+        let proof = generate_proof(&self.proving_key, &rln_witness, &self.graph_data)?;
 
         // Note: we export a serialization of ark-groth16::Proof not semaphore::Proof
         // This proof is compressed, i.e. 128 bytes long
@@ -815,34 +840,10 @@ impl RLN<'_> {
         Ok(())
     }
 
-    // TODO: this function seems to use redundant witness (as bigint and serialized) and should be refactored
-    // Generate RLN Proof using a witness calculated from outside zerokit
-    //
-    // output_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]
-    #[cfg(target_arch = "wasm32")]
-    pub fn generate_rln_proof_with_witness<W: Write>(
-        &mut self,
-        calculated_witness: Vec<BigInt>,
-        rln_witness_vec: Vec<u8>,
-        mut output_data: W,
-    ) -> Result<()> {
-        let (rln_witness, _) = deserialize_witness(&rln_witness_vec[..])?;
-        let proof_values = proof_values_from_witness(&rln_witness)?;
-
-        let proof = generate_proof_with_witness(calculated_witness, &self.proving_key).unwrap();
-
-        // Note: we export a serialization of ark-groth16::Proof not semaphore::Proof
-        // This proof is compressed, i.e. 128 bytes long
-        proof.serialize_compressed(&mut output_data)?;
-        output_data.write_all(&serialize_proof_values(&proof_values))?;
-        Ok(())
-    }
-
     // Generate RLN Proof using a witness calculated from outside zerokit
     //
     // output_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]
     // we skip it from documentation for now
-    #[cfg(not(target_arch = "wasm32"))]
     pub fn generate_rln_proof_with_witness<R: Read, W: Write>(
         &mut self,
         mut input_data: R,
@@ -853,7 +854,7 @@ impl RLN<'_> {
         let (rln_witness, _) = deserialize_witness(&witness_byte)?;
         let proof_values = proof_values_from_witness(&rln_witness)?;
 
-        let proof = generate_proof(self.witness_calculator, &self.proving_key, &rln_witness)?;
+        let proof = generate_proof(&self.proving_key, &rln_witness, &self.graph_data)?;
 
         // Note: we export a serialization of ark-groth16::Proof not semaphore::Proof
         // This proof is compressed, i.e. 128 bytes long
@@ -866,11 +867,11 @@ impl RLN<'_> {
     ///
     /// Input values are:
     /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values and the signal information,
-    ///  i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var>]`, where <_> indicates the byte length.
+    ///   i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var>]`, where <_> indicates the byte length.
     ///
     /// The function returns true if the zkSNARK proof is valid with respect to the provided circuit output values and signal. Returns false otherwise.
     ///
-    /// Note that contrary to [`verify`](crate::public::RLN::verify), this function takes additionaly as input the signal and further verifies if
+    /// Note that contrary to [`verify`](crate::public::RLN::verify), this function takes additionally as input the signal and further verifies if
     /// - the Merkle tree root corresponds to the root provided as input;
     /// - the input signal corresponds to the Shamir's x coordinate provided as input
     /// - the hardcoded application [RLN identifier](crate::public::RLN_IDENTIFIER) corresponds to the RLN identifier provided as input
@@ -882,14 +883,14 @@ impl RLN<'_> {
     /// // We prepare input for verify_rln_proof API
     /// // input_data is  `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var>]`
     /// // that is [ proof_data || signal_len<8> | signal<var> ]
-    /// proof_data.append(&mut normalize_usize(signal_len));
-    /// proof_data.append(&mut signal.to_vec());
+    /// let verify_input = prepare_verify_input(proof_data, &signal);
     ///
-    /// let mut input_buffer = Cursor::new(proof_data);
+    /// let mut input_buffer = Cursor::new(verify_input);
     /// let verified = rln.verify_rln_proof(&mut input_buffer).unwrap();
     ///
     /// assert!(verified);
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn verify_rln_proof<R: Read>(&self, mut input_data: R) -> Result<bool> {
         let mut serialized: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut serialized)?;
@@ -918,7 +919,7 @@ impl RLN<'_> {
     ///
     /// Input values are:
     /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values and the signal information, i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var>]`
-    /// - `roots_data`: a reader for the serialization of a vector of roots, i.e. `[ number_of_roots<8> | root_1<32> | ... | root_n<32> ]` (number_of_roots is a uint64 in little-endian, roots are serialized using `rln::utils::fr_to_bytes_le`))
+    /// - `roots_data`: a reader for the serialization of a vector of roots, i.e. `[ number_of_roots<8> | root_1<32> | ... | root_n<32> ]` (number_of_roots is an uint64 in little-endian, roots are serialized using `rln::utils::fr_to_bytes_le`)
     ///
     /// The function returns true if the zkSNARK proof is valid with respect to the provided circuit output values, signal and roots. Returns false otherwise.
     ///
@@ -960,7 +961,7 @@ impl RLN<'_> {
     /// roots_serialized.append(&mut fr_to_bytes_le(&root));
     /// roots_buffer = Cursor::new(roots_serialized.clone());
     /// let verified = rln
-    ///     .verify_with_roots(&mut input_buffer.clone(), &mut roots_buffer)
+    ///     .verify_with_roots(&mut input_buffer, &mut roots_buffer)
     ///     .unwrap();
     ///
     /// assert!(verified);
@@ -1063,7 +1064,7 @@ impl RLN<'_> {
     /// Generated credentials are compatible with [Semaphore](https://semaphore.appliedzkp.org/docs/guides/identities)'s credentials.
     ///
     /// Output values are:
-    /// - `output_data`: a writer receiving the serialization of the identity tapdoor, identity nullifier, identity secret and identity commitment (serialization done with `rln::utils::fr_to_bytes_le`)
+    /// - `output_data`: a writer receiving the serialization of the identity trapdoor, identity nullifier, identity secret and identity commitment (serialization done with `rln::utils::fr_to_bytes_le`)
     ///
     /// Example
     /// ```
@@ -1138,7 +1139,7 @@ impl RLN<'_> {
     /// - `input_data`: a reader for the byte vector containing the seed
     ///
     /// Output values are:
-    /// - `output_data`: a writer receiving the serialization of the identity tapdoor, identity nullifier, identity secret and identity commitment (serialization done with `rln::utils::fr_to_bytes_le`)
+    /// - `output_data`: a writer receiving the serialization of the identity trapdoor, identity nullifier, identity secret and identity commitment (serialization done with `rln::utils::fr_to_bytes_le`)
     ///
     /// Example
     /// ```
@@ -1176,8 +1177,8 @@ impl RLN<'_> {
     ///
     /// Input values are:
     /// - `input_proof_data_1`: a reader for the serialization of a RLN zkSNARK proof concatenated with a serialization of the circuit output values and -optionally- the signal information,
-    /// i.e. either `[proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]`
-    /// or `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]` (to maintain compatibility with both output of [`generate_rln_proof`](crate::public::RLN::generate_rln_proof) and input of [`verify_rln_proof`](crate::public::RLN::verify_rln_proof))
+    ///   i.e. either `[proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]`
+    ///   or `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]` (to maintain compatibility with both output of [`generate_rln_proof`](crate::public::RLN::generate_rln_proof) and input of [`verify_rln_proof`](crate::public::RLN::verify_rln_proof))
     /// - `input_proof_data_2`: same as `input_proof_data_1`
     ///
     /// Output values are:
@@ -1212,7 +1213,7 @@ impl RLN<'_> {
         mut input_proof_data_2: R,
         mut output_data: W,
     ) -> Result<()> {
-        // We serialize_compressed the two proofs and we get the corresponding RLNProofValues objects
+        // We serialize_compressed the two proofs, and we get the corresponding RLNProofValues objects
         let mut serialized: Vec<u8> = Vec::new();
         input_proof_data_1.read_to_end(&mut serialized)?;
         // We skip deserialization of the zk-proof at the beginning
@@ -1228,7 +1229,7 @@ impl RLN<'_> {
         // We continue only if the proof values are for the same external nullifier (which includes epoch and rln identifier)
         // The idea is that proof values that go as input to this function are verified first (with zk-proof verify), hence ensuring validity of external nullifier and other fields.
         // Only in case all fields are valid, an external_nullifier for the message will be stored (otherwise signal/proof will be simply discarded)
-        // If the nullifier matches one already seen, we can recovery of identity secret.
+        // If the nullifier matches one already seen, we can recover of identity secret.
         if external_nullifier_1 == external_nullifier_2 {
             // We extract the two shares
             let share1 = (proof_values_1.x, proof_values_1.y);
@@ -1248,12 +1249,13 @@ impl RLN<'_> {
         Ok(())
     }
 
-    /// Returns the serialization of a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) populated from the identity secret, the Merkle tree index, the user message limit, the message id, the external nullifier (which include epoch and rln identifier) and signal.
+    /// Returns the serialization of a [`RLNWitnessInput`] populated from the identity secret, the Merkle tree index, the user message limit, the message id, the external nullifier (which include epoch and rln identifier) and signal.
     ///
     /// Input values are:
     /// - `input_data`: a reader for the serialization of `[ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]`
     ///
-    /// The function returns the corresponding [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object serialized using [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness)).
+    /// The function returns the corresponding [`RLNWitnessInput`] object serialized using [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness).
+    #[cfg(not(feature = "stateless"))]
     pub fn get_serialized_rln_witness<R: Read>(&mut self, mut input_data: R) -> Result<Vec<u8>> {
         // We read input RLN witness and we serialize_compressed it
         let mut witness_byte: Vec<u8> = Vec::new();
@@ -1263,32 +1265,52 @@ impl RLN<'_> {
         serialize_witness(&rln_witness)
     }
 
-    /// Converts a byte serialization of a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object to the corresponding JSON serialization.
+    /// Converts a byte serialization of a [`RLNWitnessInput`] object to the corresponding JSON serialization.
     ///
     /// Input values are:
-    /// - `serialized_witness`: the byte serialization of a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object (serialization done with  [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness)).
+    /// - `serialized_witness`: the byte serialization of a [`RLNWitnessInput`] object (serialization done with  [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness)).
     ///
-    /// The function returns the corresponding JSON encoding of the input [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object.
+    /// The function returns the corresponding JSON encoding of the input [`RLNWitnessInput`] object.
     pub fn get_rln_witness_json(&mut self, serialized_witness: &[u8]) -> Result<serde_json::Value> {
         let (rln_witness, _) = deserialize_witness(serialized_witness)?;
         rln_witness_to_json(&rln_witness)
     }
 
+    /// Converts a byte serialization of a [`RLNWitnessInput`] object to the corresponding JSON serialization.
+    /// Before serialization the data will be translated into big int for further calculation in the witness calculator.
+    ///
+    /// Input values are:
+    /// - `serialized_witness`: the byte serialization of a [`RLNWitnessInput`] object (serialization done with  [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness)).
+    ///
+    /// The function returns the corresponding JSON encoding of the input [`RLNWitnessInput`] object.
+    pub fn get_rln_witness_bigint_json(
+        &mut self,
+        serialized_witness: &[u8],
+    ) -> Result<serde_json::Value> {
+        let (rln_witness, _) = deserialize_witness(serialized_witness)?;
+        rln_witness_to_bigint_json(&rln_witness)
+    }
+
     /// Closes the connection to the Merkle tree database.
     /// This function should be called before the RLN object is dropped.
     /// If not called, the connection will be closed when the RLN object is dropped.
     /// This improves robustness of the tree.
+    #[cfg(not(feature = "stateless"))]
     pub fn flush(&mut self) -> Result<()> {
         self.tree.close_db_connection()
     }
 }
 
-#[cfg(not(target_arch = "wasm32"))]
-impl Default for RLN<'_> {
+impl Default for RLN {
     fn default() -> Self {
-        let tree_height = TEST_TREE_HEIGHT;
-        let buffer = Cursor::new(json!({}).to_string());
-        Self::new(tree_height, buffer).unwrap()
+        #[cfg(not(feature = "stateless"))]
+        {
+            let tree_height = TEST_TREE_HEIGHT;
+            let buffer = Cursor::new(json!({}).to_string());
+            Self::new(tree_height, buffer).unwrap()
+        }
+        #[cfg(feature = "stateless")]
+        Self::new().unwrap()
     }
 }
 

rln/src/utils.rs

@@ -1,24 +1,26 @@
 // This crate provides cross-module useful utilities (mainly type conversions) not necessarily specific to RLN
 
-use crate::circuit::Fr;
 use ark_ff::PrimeField;
 use color_eyre::{Report, Result};
 use num_bigint::{BigInt, BigUint};
 use num_traits::Num;
 use serde_json::json;
 use std::io::Cursor;
-use std::iter::Extend;
 
+use crate::circuit::Fr;
+
+#[inline(always)]
 pub fn to_bigint(el: &Fr) -> Result<BigInt> {
-    let res: BigUint = (*el).into();
-    Ok(res.into())
+    Ok(BigUint::from(*el).into())
 }
 
+#[inline(always)]
 pub fn fr_byte_size() -> usize {
     let mbs = <Fr as PrimeField>::MODULUS_BIT_SIZE;
     ((mbs + 64 - (mbs % 64)) / 8) as usize
 }
 
+#[inline(always)]
 pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
     if !(radix == 10 || radix == 16) {
         return Err(Report::msg("wrong radix"));
@@ -37,6 +39,7 @@ pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
     }
 }
 
+#[inline(always)]
 pub fn bytes_le_to_fr(input: &[u8]) -> (Fr, usize) {
     let el_size = fr_byte_size();
     (
@@ -45,77 +48,50 @@ pub fn bytes_le_to_fr(input: &[u8]) -> (Fr, usize) {
     )
 }
 
-pub fn bytes_be_to_fr(input: &[u8]) -> (Fr, usize) {
-    let el_size = fr_byte_size();
-    (
-        Fr::from(BigUint::from_bytes_be(&input[0..el_size])),
-        el_size,
-    )
-}
-
+#[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
-}
-
-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);
-    }
+    res.resize(fr_byte_size(), 0);
     res
 }
 
+#[inline(always)]
 pub fn vec_fr_to_bytes_le(input: &[Fr]) -> Result<Vec<u8>> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(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(input.len()));
 
     // We store each element
-    input.iter().for_each(|el| bytes.extend(fr_to_bytes_le(el)));
-
-    Ok(bytes)
-}
-
-pub fn vec_fr_to_bytes_be(input: &[Fr]) -> Result<Vec<u8>> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len())?.to_be_bytes().to_vec());
-
-    // 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_le(el));
+    }
 
     Ok(bytes)
 }
 
+#[inline(always)]
 pub fn vec_u8_to_bytes_le(input: &[u8]) -> Result<Vec<u8>> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len())?.to_le_bytes().to_vec());
+    // Calculate capacity for Vec:
+    // - 8 bytes for normalized vector length (usize)
+    // - variable length input data
+    let mut bytes = Vec::with_capacity(8 + input.len());
 
-    bytes.extend(input);
-
-    Ok(bytes)
-}
-
-pub fn vec_u8_to_bytes_be(input: Vec<u8>) -> Result<Vec<u8>> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len())?.to_be_bytes().to_vec());
-
-    bytes.extend(input);
+    // We store the vector length
+    bytes.extend_from_slice(&normalize_usize(input.len()));
+
+    // We store the input
+    bytes.extend_from_slice(input);
 
     Ok(bytes)
 }
 
+#[inline(always)]
 pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize)> {
     let mut read: usize = 0;
 
@@ -128,19 +104,7 @@ pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize)> {
     Ok((res, read))
 }
 
-pub fn bytes_be_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize)> {
-    let mut read: usize = 0;
-
-    let len = usize::try_from(u64::from_be_bytes(input[0..8].try_into()?))?;
-    read += 8;
-
-    let res = input[8..8 + len].to_vec();
-
-    read += res.len();
-
-    Ok((res, read))
-}
-
+#[inline(always)]
 pub fn bytes_le_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize)> {
     let mut read: usize = 0;
     let mut res: Vec<Fr> = Vec::new();
@@ -158,29 +122,7 @@ pub fn bytes_le_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize)> {
     Ok((res, read))
 }
 
-pub fn bytes_be_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize)> {
-    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()?))?;
-    read += 8;
-
-    let el_size = fr_byte_size();
-    for i in 0..len {
-        let (curr_el, _) = bytes_be_to_fr(&input[8 + el_size * i..8 + el_size * (i + 1)]);
-        res.push(curr_el);
-        read += el_size;
-    }
-
-    Ok((res, read))
-}
-
-pub fn normalize_usize(input: usize) -> Vec<u8> {
-    let mut normalized_usize = input.to_le_bytes().to_vec();
-    normalized_usize.resize(8, 0);
-    normalized_usize
-}
-
+#[inline(always)]
 pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>> {
     let nof_elem = usize::try_from(u64::from_le_bytes(input[0..8].try_into()?))?;
     if nof_elem == 0 {
@@ -194,141 +136,12 @@ pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>> {
     }
 }
 
-// using for test
+#[inline(always)]
+pub fn normalize_usize(input: usize) -> [u8; 8] {
+    input.to_le_bytes()
+}
+
+#[inline(always)] // using for test
 pub fn generate_input_buffer() -> Cursor<String> {
     Cursor::new(json!({}).to_string())
 }
-
-/* 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()
-    } else {
-        let input_clean = input_clean.replace("0x", "");
-        Field::from_str(&format!("{:0>64}", &input_clean)).unwrap()
-    }
-}
-
-pub fn bytes_le_to_field(input: &[u8]) -> (Field, usize) {
-    let (fr_el, read) = bytes_le_to_fr(input);
-    (to_field(&fr_el), read)
-}
-
-pub fn bytes_be_to_field(input: &[u8]) -> (Field, usize) {
-    let (fr_el, read) = bytes_be_to_fr(input);
-    (to_field(&fr_el), read)
-}
-
-
-pub fn field_to_bytes_le(input: &Field) -> Vec<u8> {
-    fr_to_bytes_le(&to_fr(input))
-}
-
-pub fn field_to_bytes_be(input: &Field) -> Vec<u8> {
-    fr_to_bytes_be(&to_fr(input))
-}
-
-
-pub fn vec_field_to_bytes_le(input: &[Field]) -> Vec<u8> {
-    vec_fr_to_bytes_le(&vec_field_to_fr(input))
-}
-
-pub fn vec_field_to_bytes_be(input: &[Field]) -> Vec<u8> {
-    vec_fr_to_bytes_be(&vec_field_to_fr(input))
-}
-
-
-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)
-}
-
-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)
-}
-
-// 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)))
-}
-
-pub fn mul(a: &Field, b: &Field) -> Field {
-    to_field(&(to_fr(a) * to_fr(b)))
-}
-
-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/ffi.rs

@@ -1,4 +1,5 @@
 #[cfg(test)]
+#[cfg(not(feature = "stateless"))]
 mod test {
     use ark_std::{rand::thread_rng, UniformRand};
     use rand::Rng;
@@ -16,7 +17,7 @@ mod test {
 
     const NO_OF_LEAVES: usize = 256;
 
-    fn create_rln_instance() -> &'static mut RLN<'static> {
+    fn create_rln_instance() -> &'static mut RLN {
         let mut rln_pointer = MaybeUninit::<*mut RLN>::uninit();
         let input_config = json!({}).to_string();
         let input_buffer = &Buffer::from(input_config.as_bytes());
@@ -407,15 +408,6 @@ mod test {
         // We obtain the root from the RLN instance
         let root_rln_folder = get_tree_root(rln_pointer);
 
-        // Reading the raw data from the files required for instantiating a RLN instance using raw data
-        let circom_path = "./resources/tree_height_20/rln.wasm";
-        let mut circom_file = File::open(&circom_path).expect("no file found");
-        let metadata = std::fs::metadata(&circom_path).expect("unable to read metadata");
-        let mut circom_buffer = vec![0; metadata.len() as usize];
-        circom_file
-            .read_exact(&mut circom_buffer)
-            .expect("buffer overflow");
-
         #[cfg(feature = "arkzkey")]
         let zkey_path = "./resources/tree_height_20/rln_final.arkzkey";
         #[cfg(not(feature = "arkzkey"))]
@@ -427,15 +419,17 @@ mod test {
             .read_exact(&mut zkey_buffer)
             .expect("buffer overflow");
 
-        let vk_path = "./resources/tree_height_20/verification_key.json";
-        let mut vk_file = File::open(&vk_path).expect("no file found");
-        let metadata = std::fs::metadata(&vk_path).expect("unable to read metadata");
-        let mut vk_buffer = vec![0; metadata.len() as usize];
-        vk_file.read_exact(&mut vk_buffer).expect("buffer overflow");
-
-        let circom_data = &Buffer::from(&circom_buffer[..]);
         let zkey_data = &Buffer::from(&zkey_buffer[..]);
-        let vk_data = &Buffer::from(&vk_buffer[..]);
+
+        let graph_data = "./resources/tree_height_20/graph.bin";
+        let mut graph_file = File::open(&graph_data).expect("no file found");
+        let metadata = std::fs::metadata(&graph_data).expect("unable to read metadata");
+        let mut graph_buffer = vec![0; metadata.len() as usize];
+        graph_file
+            .read_exact(&mut graph_buffer)
+            .expect("buffer overflow");
+
+        let graph_data = &Buffer::from(&graph_buffer[..]);
 
         // Creating a RLN instance passing the raw data
         let mut rln_pointer_raw_bytes = MaybeUninit::<*mut RLN>::uninit();
@@ -443,9 +437,8 @@ mod test {
         let tree_config_buffer = &Buffer::from(tree_config.as_bytes());
         let success = new_with_params(
             TEST_TREE_HEIGHT,
-            circom_data,
             zkey_data,
-            vk_data,
+            graph_data,
             tree_config_buffer,
             rln_pointer_raw_bytes.as_mut_ptr(),
         );
@@ -485,10 +478,13 @@ mod test {
 
         // We generate a random epoch
         let epoch = hash_to_field(b"test-epoch");
+        // We generate a random rln_identifier
         let rln_identifier = hash_to_field(b"test-rln-identifier");
+        // We generate a external nullifier
         let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
+        // We choose a message_id satisfy 0 <= message_id < MESSAGE_LIMIT
+        let message_id = Fr::from(1);
 
-        let message_id = Fr::from(0);
         let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
 
         // We set as leaf rate_commitment, its index would be equal to no_of_leaves
@@ -499,27 +495,25 @@ mod test {
 
         // We prepare input for generate_rln_proof API
         // input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
-        let mut serialized: Vec<u8> = Vec::new();
-        serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
-        serialized.append(&mut normalize_usize(identity_index));
-        serialized.append(&mut fr_to_bytes_le(&user_message_limit));
-        serialized.append(&mut fr_to_bytes_le(&message_id));
-        serialized.append(&mut fr_to_bytes_le(&external_nullifier));
-        serialized.append(&mut normalize_usize(signal.len()));
-        serialized.append(&mut signal.to_vec());
-
+        let prove_input = prepare_prove_input(
+            identity_secret_hash,
+            identity_index,
+            user_message_limit,
+            message_id,
+            external_nullifier,
+            &signal,
+        );
         // We call generate_rln_proof
         // result_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let mut proof_data = rln_proof_gen(rln_pointer, serialized.as_ref());
+        let proof_data = rln_proof_gen(rln_pointer, prove_input.as_ref());
 
         // We prepare input for verify_rln_proof API
         // input_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
-        // that is [ proof_data | signal_len<8> | signal<var> ]
-        proof_data.append(&mut normalize_usize(signal.len()));
-        proof_data.append(&mut signal.to_vec());
+        // that is [ proof_data || signal_len<8> | signal<var> ]
+        let verify_input = prepare_verify_input(proof_data, &signal);
 
         // We call verify_rln_proof
-        let input_buffer = &Buffer::from(proof_data.as_ref());
+        let input_buffer = &Buffer::from(verify_input.as_ref());
         let mut proof_is_valid: bool = false;
         let proof_is_valid_ptr = &mut proof_is_valid as *mut bool;
         let success = verify_rln_proof(rln_pointer, input_buffer, proof_is_valid_ptr);
@@ -529,7 +523,7 @@ mod test {
 
     #[test]
     // Computes and verifies an RLN ZK proof by checking proof's root against an input roots buffer
-    fn test_verify_with_roots() {
+    fn test_verify_with_roots_ffi() {
         // First part similar to test_rln_proof_ffi
         let user_message_limit = Fr::from(100);
 
@@ -552,11 +546,12 @@ mod test {
 
         // We generate a random epoch
         let epoch = hash_to_field(b"test-epoch");
+        // We generate a random rln_identifier
         let rln_identifier = hash_to_field(b"test-rln-identifier");
+        // We generate a external nullifier
         let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
-
-        let user_message_limit = Fr::from(100);
-        let message_id = Fr::from(0);
+        // We choose a message_id satisfy 0 <= message_id < MESSAGE_LIMIT
+        let message_id = Fr::from(1);
 
         // We set as leaf rate_commitment, its index would be equal to no_of_leaves
         let leaf_ser = fr_to_bytes_le(&rate_commitment);
@@ -566,24 +561,23 @@ mod test {
 
         // We prepare input for generate_rln_proof API
         // input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
-        let mut serialized: Vec<u8> = Vec::new();
-        serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
-        serialized.append(&mut normalize_usize(identity_index));
-        serialized.append(&mut fr_to_bytes_le(&user_message_limit));
-        serialized.append(&mut fr_to_bytes_le(&message_id));
-        serialized.append(&mut fr_to_bytes_le(&external_nullifier));
-        serialized.append(&mut normalize_usize(signal.len()));
-        serialized.append(&mut signal.to_vec());
+        let prove_input = prepare_prove_input(
+            identity_secret_hash,
+            identity_index,
+            user_message_limit,
+            message_id,
+            external_nullifier,
+            &signal,
+        );
 
         // We call generate_rln_proof
         // result_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let mut proof_data = rln_proof_gen(rln_pointer, serialized.as_ref());
+        let proof_data = rln_proof_gen(rln_pointer, prove_input.as_ref());
 
         // We prepare input for verify_rln_proof API
         // input_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
-        // that is [ proof_data | signal_len<8> | signal<var> ]
-        proof_data.append(&mut normalize_usize(signal.len()));
-        proof_data.append(&mut signal.to_vec());
+        // that is [ proof_data || signal_len<8> | signal<var> ]
+        let verify_input = prepare_verify_input(proof_data.clone(), &signal);
 
         // We test verify_with_roots
 
@@ -591,7 +585,7 @@ mod test {
         // In this case, since no root is provided, proof's root check is skipped and proof is verified if other proof values are valid
         let mut roots_data: Vec<u8> = Vec::new();
 
-        let input_buffer = &Buffer::from(proof_data.as_ref());
+        let input_buffer = &Buffer::from(verify_input.as_ref());
         let roots_buffer = &Buffer::from(roots_data.as_ref());
         let mut proof_is_valid: bool = false;
         let proof_is_valid_ptr = &mut proof_is_valid as *mut bool;
@@ -605,7 +599,7 @@ mod test {
         for _ in 0..5 {
             roots_data.append(&mut fr_to_bytes_le(&Fr::rand(&mut rng)));
         }
-        let input_buffer = &Buffer::from(proof_data.as_ref());
+        let input_buffer = &Buffer::from(verify_input.as_ref());
         let roots_buffer = &Buffer::from(roots_data.as_ref());
         let mut proof_is_valid: bool = false;
         let proof_is_valid_ptr = &mut proof_is_valid as *mut bool;
@@ -621,7 +615,7 @@ mod test {
 
         // We include the root and verify the proof
         roots_data.append(&mut fr_to_bytes_le(&root));
-        let input_buffer = &Buffer::from(proof_data.as_ref());
+        let input_buffer = &Buffer::from(verify_input.as_ref());
         let roots_buffer = &Buffer::from(roots_data.as_ref());
         let mut proof_is_valid: bool = false;
         let proof_is_valid_ptr = &mut proof_is_valid as *mut bool;
@@ -642,7 +636,6 @@ mod test {
         let (identity_secret_hash, id_commitment) = identity_pair_gen(rln_pointer);
 
         let user_message_limit = Fr::from(100);
-        let message_id = Fr::from(0);
         let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
 
         // We set as leaf rate_commitment, its index would be equal to 0 since tree is empty
@@ -664,36 +657,40 @@ mod test {
 
         // We generate a random epoch
         let epoch = hash_to_field(b"test-epoch");
+        // We generate a random rln_identifier
         let rln_identifier = hash_to_field(b"test-rln-identifier");
+        // We generate a external nullifier
         let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
+        // We choose a message_id satisfy 0 <= message_id < MESSAGE_LIMIT
+        let message_id = Fr::from(1);
 
         // We prepare input for generate_rln_proof API
-        // input_data is [ identity_secret<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]
-        let mut serialized1: Vec<u8> = Vec::new();
-        serialized1.append(&mut fr_to_bytes_le(&identity_secret_hash));
-        serialized1.append(&mut normalize_usize(identity_index));
-        serialized1.append(&mut fr_to_bytes_le(&user_message_limit));
-        serialized1.append(&mut fr_to_bytes_le(&message_id));
-        serialized1.append(&mut fr_to_bytes_le(&external_nullifier));
+        // input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
+        let prove_input1 = prepare_prove_input(
+            identity_secret_hash,
+            identity_index,
+            user_message_limit,
+            message_id,
+            external_nullifier,
+            &signal1,
+        );
 
-        // The first part is the same for both proof input, so we clone
-        let mut serialized2 = serialized1.clone();
-
-        // We attach the first signal to the first proof input
-        serialized1.append(&mut normalize_usize(signal1.len()));
-        serialized1.append(&mut signal1.to_vec());
-
-        // We attach the second signal to the first proof input
-        serialized2.append(&mut normalize_usize(signal2.len()));
-        serialized2.append(&mut signal2.to_vec());
+        let prove_input2 = prepare_prove_input(
+            identity_secret_hash,
+            identity_index,
+            user_message_limit,
+            message_id,
+            external_nullifier,
+            &signal2,
+        );
 
         // We call generate_rln_proof for first proof values
         // result_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let proof_data_1 = rln_proof_gen(rln_pointer, serialized1.as_ref());
+        let proof_data_1 = rln_proof_gen(rln_pointer, prove_input1.as_ref());
 
         // We call generate_rln_proof
         // result_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let proof_data_2 = rln_proof_gen(rln_pointer, serialized2.as_ref());
+        let proof_data_2 = rln_proof_gen(rln_pointer, prove_input2.as_ref());
 
         let input_proof_buffer_1 = &Buffer::from(proof_data_1.as_ref());
         let input_proof_buffer_2 = &Buffer::from(proof_data_2.as_ref());
@@ -736,18 +733,18 @@ mod test {
         // We prepare input for generate_rln_proof API
         // input_data is [ identity_secret<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]
         // Note that epoch is the same as before
-        let mut serialized: Vec<u8> = Vec::new();
-        serialized.append(&mut fr_to_bytes_le(&identity_secret_hash_new));
-        serialized.append(&mut normalize_usize(identity_index_new));
-        serialized.append(&mut fr_to_bytes_le(&user_message_limit));
-        serialized.append(&mut fr_to_bytes_le(&message_id));
-        serialized.append(&mut fr_to_bytes_le(&external_nullifier));
-        serialized.append(&mut normalize_usize(signal3.len()));
-        serialized.append(&mut signal3.to_vec());
+        let prove_input3 = prepare_prove_input(
+            identity_secret_hash,
+            identity_index_new,
+            user_message_limit,
+            message_id,
+            external_nullifier,
+            &signal3,
+        );
 
         // We call generate_rln_proof
         // result_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let proof_data_3 = rln_proof_gen(rln_pointer, serialized.as_ref());
+        let proof_data_3 = rln_proof_gen(rln_pointer, prove_input3.as_ref());
 
         // We attempt to recover the secret using share1 (coming from identity_secret_hash) and share3 (coming from identity_secret_hash_new)
 
@@ -905,7 +902,7 @@ mod test {
     }
 
     #[test]
-    fn test_get_leaf() {
+    fn test_get_leaf_ffi() {
         // We create a RLN instance
         let no_of_leaves = 1 << TEST_TREE_HEIGHT;
 
@@ -945,7 +942,7 @@ mod test {
     }
 
     #[test]
-    fn test_valid_metadata() {
+    fn test_valid_metadata_ffi() {
         // We create a RLN instance
         let rln_pointer = create_rln_instance();
 
@@ -966,7 +963,7 @@ mod test {
     }
 
     #[test]
-    fn test_empty_metadata() {
+    fn test_empty_metadata_ffi() {
         // We create a RLN instance
         let rln_pointer = create_rln_instance();
 
@@ -978,3 +975,470 @@ mod test {
         assert_eq!(output_buffer.len, 0);
     }
 }
+
+#[cfg(test)]
+#[cfg(feature = "stateless")]
+mod stateless_test {
+    use ark_std::{rand::thread_rng, UniformRand};
+    use rand::Rng;
+    use rln::circuit::*;
+    use rln::ffi::generate_rln_proof_with_witness;
+    use rln::ffi::{hash as ffi_hash, poseidon_hash as ffi_poseidon_hash, *};
+    use rln::hashers::{hash_to_field, poseidon_hash as utils_poseidon_hash, ROUND_PARAMS};
+    use rln::poseidon_tree::PoseidonTree;
+    use rln::protocol::*;
+    use rln::public::RLN;
+    use rln::utils::*;
+    use std::mem::MaybeUninit;
+    use std::time::{Duration, Instant};
+    use utils::ZerokitMerkleTree;
+
+    type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
+
+    fn create_rln_instance() -> &'static mut RLN {
+        let mut rln_pointer = MaybeUninit::<*mut RLN>::uninit();
+        let success = new(rln_pointer.as_mut_ptr());
+        assert!(success, "RLN object creation failed");
+        unsafe { &mut *rln_pointer.assume_init() }
+    }
+
+    fn identity_pair_gen(rln_pointer: &mut RLN) -> (Fr, Fr) {
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success = key_gen(rln_pointer, output_buffer.as_mut_ptr());
+        assert!(success, "key gen call failed");
+        let output_buffer = unsafe { output_buffer.assume_init() };
+        let result_data = <&[u8]>::from(&output_buffer).to_vec();
+        let (identity_secret_hash, read) = bytes_le_to_fr(&result_data);
+        let (id_commitment, _) = bytes_le_to_fr(&result_data[read..].to_vec());
+        (identity_secret_hash, id_commitment)
+    }
+
+    fn rln_proof_gen_with_witness(rln_pointer: &mut RLN, serialized: &[u8]) -> Vec<u8> {
+        let input_buffer = &Buffer::from(serialized);
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success =
+            generate_rln_proof_with_witness(rln_pointer, input_buffer, output_buffer.as_mut_ptr());
+        assert!(success, "generate rln proof call failed");
+        let output_buffer = unsafe { output_buffer.assume_init() };
+        <&[u8]>::from(&output_buffer).to_vec()
+    }
+
+    #[test]
+    fn test_recover_id_secret_stateless_ffi() {
+        let default_leaf = Fr::from(0);
+        let mut tree = PoseidonTree::new(
+            TEST_TREE_HEIGHT,
+            default_leaf,
+            ConfigOf::<PoseidonTree>::default(),
+        )
+        .unwrap();
+
+        let rln_pointer = create_rln_instance();
+
+        // We generate a new identity pair
+        let (identity_secret_hash, id_commitment) = identity_pair_gen(rln_pointer);
+
+        let user_message_limit = Fr::from(100);
+        let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
+        tree.update_next(rate_commitment).unwrap();
+
+        // We generate a random epoch
+        let epoch = hash_to_field(b"test-epoch");
+        let rln_identifier = hash_to_field(b"test-rln-identifier");
+        let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
+
+        // We generate two proofs using same epoch but different signals.
+        // We generate a random signal
+        let mut rng = thread_rng();
+        let signal1: [u8; 32] = rng.gen();
+        let x1 = hash_to_field(&signal1);
+
+        let signal2: [u8; 32] = rng.gen();
+        let x2 = hash_to_field(&signal2);
+
+        let identity_index = tree.leaves_set();
+        let merkle_proof = tree.proof(identity_index).expect("proof should exist");
+
+        // We prepare input for generate_rln_proof API
+        let rln_witness1 = rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x1,
+            external_nullifier,
+            user_message_limit,
+            Fr::from(1),
+        )
+        .unwrap();
+        let serialized1 = serialize_witness(&rln_witness1).unwrap();
+
+        let rln_witness2 = rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x2,
+            external_nullifier,
+            user_message_limit,
+            Fr::from(1),
+        )
+        .unwrap();
+        let serialized2 = serialize_witness(&rln_witness2).unwrap();
+
+        // We call generate_rln_proof for first proof values
+        // result_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+        let proof_data_1 = rln_proof_gen_with_witness(rln_pointer, serialized1.as_ref());
+
+        // We call generate_rln_proof
+        // result_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+        let proof_data_2 = rln_proof_gen_with_witness(rln_pointer, serialized2.as_ref());
+
+        let input_proof_buffer_1 = &Buffer::from(proof_data_1.as_ref());
+        let input_proof_buffer_2 = &Buffer::from(proof_data_2.as_ref());
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success = recover_id_secret(
+            rln_pointer,
+            input_proof_buffer_1,
+            input_proof_buffer_2,
+            output_buffer.as_mut_ptr(),
+        );
+        assert!(success, "recover id secret call failed");
+        let output_buffer = unsafe { output_buffer.assume_init() };
+        let serialized_identity_secret_hash = <&[u8]>::from(&output_buffer).to_vec();
+
+        // We passed two shares for the same secret, so recovery should be successful
+        // To check it, we ensure that recovered identity secret hash is empty
+        assert!(!serialized_identity_secret_hash.is_empty());
+
+        // We check if the recovered identity secret hash corresponds to the original one
+        let (recovered_identity_secret_hash, _) = bytes_le_to_fr(&serialized_identity_secret_hash);
+        assert_eq!(recovered_identity_secret_hash, identity_secret_hash);
+
+        // We now test that computing identity_secret_hash is unsuccessful if shares computed from two different identity secret hashes but within same epoch are passed
+
+        // We generate a new identity pair
+        let (identity_secret_hash_new, id_commitment_new) = identity_pair_gen(rln_pointer);
+        let rate_commitment_new = utils_poseidon_hash(&[id_commitment_new, user_message_limit]);
+        tree.update_next(rate_commitment_new).unwrap();
+
+        // We generate a random signals
+        let signal3: [u8; 32] = rng.gen();
+        let x3 = hash_to_field(&signal3);
+
+        let identity_index_new = tree.leaves_set();
+        let merkle_proof_new = tree.proof(identity_index_new).expect("proof should exist");
+
+        let rln_witness3 = rln_witness_from_values(
+            identity_secret_hash_new,
+            &merkle_proof_new,
+            x3,
+            external_nullifier,
+            user_message_limit,
+            Fr::from(1),
+        )
+        .unwrap();
+        let serialized3 = serialize_witness(&rln_witness3).unwrap();
+
+        // We call generate_rln_proof
+        // result_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+        let proof_data_3 = rln_proof_gen_with_witness(rln_pointer, serialized3.as_ref());
+
+        // We attempt to recover the secret using share1 (coming from identity_secret_hash) and share3 (coming from identity_secret_hash_new)
+
+        let input_proof_buffer_1 = &Buffer::from(proof_data_1.as_ref());
+        let input_proof_buffer_3 = &Buffer::from(proof_data_3.as_ref());
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success = recover_id_secret(
+            rln_pointer,
+            input_proof_buffer_1,
+            input_proof_buffer_3,
+            output_buffer.as_mut_ptr(),
+        );
+        assert!(success, "recover id secret call failed");
+        let output_buffer = unsafe { output_buffer.assume_init() };
+        let serialized_identity_secret_hash = <&[u8]>::from(&output_buffer).to_vec();
+        let (recovered_identity_secret_hash_new, _) =
+            bytes_le_to_fr(&serialized_identity_secret_hash);
+
+        // ensure that the recovered secret does not match with either of the
+        // used secrets in proof generation
+        assert_ne!(recovered_identity_secret_hash_new, identity_secret_hash_new);
+    }
+
+    #[test]
+    fn test_verify_with_roots_stateless_ffi() {
+        let default_leaf = Fr::from(0);
+        let mut tree = PoseidonTree::new(
+            TEST_TREE_HEIGHT,
+            default_leaf,
+            ConfigOf::<PoseidonTree>::default(),
+        )
+        .unwrap();
+
+        let rln_pointer = create_rln_instance();
+
+        // We generate a new identity pair
+        let (identity_secret_hash, id_commitment) = identity_pair_gen(rln_pointer);
+
+        let identity_index = tree.leaves_set();
+        let user_message_limit = Fr::from(100);
+        let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
+        tree.update_next(rate_commitment).unwrap();
+
+        // We generate a random epoch
+        let epoch = hash_to_field(b"test-epoch");
+        let rln_identifier = hash_to_field(b"test-rln-identifier");
+        let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
+
+        // We generate two proofs using same epoch but different signals.
+        // We generate a random signal
+        let mut rng = thread_rng();
+        let signal: [u8; 32] = rng.gen();
+        let x = hash_to_field(&signal);
+
+        let merkle_proof = tree.proof(identity_index).expect("proof should exist");
+
+        // We prepare input for generate_rln_proof API
+        let rln_witness = rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x,
+            external_nullifier,
+            user_message_limit,
+            Fr::from(1),
+        )
+        .unwrap();
+
+        let serialized = serialize_witness(&rln_witness).unwrap();
+        let proof_data = rln_proof_gen_with_witness(rln_pointer, serialized.as_ref());
+
+        let verify_input = prepare_verify_input(proof_data.clone(), &signal);
+
+        // If no roots is provided, proof validation is skipped and if the remaining proof values are valid, the proof will be correctly verified
+        let mut roots_data: Vec<u8> = Vec::new();
+
+        let input_buffer = &Buffer::from(verify_input.as_ref());
+        let roots_buffer = &Buffer::from(roots_data.as_ref());
+        let mut proof_is_valid: bool = false;
+        let proof_is_valid_ptr = &mut proof_is_valid as *mut bool;
+        let success =
+            verify_with_roots(rln_pointer, input_buffer, roots_buffer, proof_is_valid_ptr);
+        assert!(success, "verify call failed");
+        // Proof should be valid
+        assert_eq!(proof_is_valid, true);
+
+        // We serialize in the roots buffer some random values and we check that the proof is not verified since doesn't contain the correct root the proof refers to
+        for _ in 0..5 {
+            roots_data.append(&mut fr_to_bytes_le(&Fr::rand(&mut rng)));
+        }
+        let input_buffer = &Buffer::from(verify_input.as_ref());
+        let roots_buffer = &Buffer::from(roots_data.as_ref());
+        let mut proof_is_valid: bool = false;
+        let proof_is_valid_ptr = &mut proof_is_valid as *mut bool;
+        let success =
+            verify_with_roots(rln_pointer, input_buffer, roots_buffer, proof_is_valid_ptr);
+        assert!(success, "verify call failed");
+        // Proof should be invalid.
+        assert_eq!(proof_is_valid, false);
+
+        // We get the root of the tree obtained adding one leaf per time
+        let root = tree.root();
+
+        // We add the real root and we check if now the proof is verified
+        roots_data.append(&mut fr_to_bytes_le(&root));
+        let input_buffer = &Buffer::from(verify_input.as_ref());
+        let roots_buffer = &Buffer::from(roots_data.as_ref());
+        let mut proof_is_valid: bool = false;
+        let proof_is_valid_ptr = &mut proof_is_valid as *mut bool;
+        let success =
+            verify_with_roots(rln_pointer, input_buffer, roots_buffer, proof_is_valid_ptr);
+        assert!(success, "verify call failed");
+        // Proof should be valid.
+        assert_eq!(proof_is_valid, true);
+    }
+
+    #[test]
+    fn test_groth16_proofs_performance_stateless_ffi() {
+        // We create a RLN instance
+        let rln_pointer = create_rln_instance();
+
+        // We compute some benchmarks regarding proof and verify API calls
+        // Note that circuit loading requires some initial overhead.
+        // Once the circuit is loaded (i.e., when the RLN object is created), proof generation and verification times should be similar at each call.
+        let sample_size = 100;
+        let mut prove_time: u128 = 0;
+        let mut verify_time: u128 = 0;
+
+        for _ in 0..sample_size {
+            // We generate random witness instances and relative proof values
+            let rln_witness = random_rln_witness(TEST_TREE_HEIGHT);
+            let proof_values = proof_values_from_witness(&rln_witness).unwrap();
+
+            // We prepare id_commitment and we set the leaf at provided index
+            let rln_witness_ser = serialize_witness(&rln_witness).unwrap();
+            let input_buffer = &Buffer::from(rln_witness_ser.as_ref());
+            let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+            let now = Instant::now();
+            let success = prove(rln_pointer, input_buffer, output_buffer.as_mut_ptr());
+            prove_time += now.elapsed().as_nanos();
+            assert!(success, "prove call failed");
+            let output_buffer = unsafe { output_buffer.assume_init() };
+
+            // We read the returned proof and we append proof values for verify
+            let serialized_proof = <&[u8]>::from(&output_buffer).to_vec();
+            let serialized_proof_values = serialize_proof_values(&proof_values);
+            let mut verify_data = Vec::<u8>::new();
+            verify_data.extend(&serialized_proof);
+            verify_data.extend(&serialized_proof_values);
+
+            // We prepare input proof values and we call verify
+            let input_buffer = &Buffer::from(verify_data.as_ref());
+            let mut proof_is_valid: bool = false;
+            let proof_is_valid_ptr = &mut proof_is_valid as *mut bool;
+            let now = Instant::now();
+            let success = verify(rln_pointer, input_buffer, proof_is_valid_ptr);
+            verify_time += now.elapsed().as_nanos();
+            assert!(success, "verify call failed");
+            assert_eq!(proof_is_valid, true);
+        }
+
+        println!(
+            "Average prove API call time: {:?}",
+            Duration::from_nanos((prove_time / sample_size).try_into().unwrap())
+        );
+        println!(
+            "Average verify API call time: {:?}",
+            Duration::from_nanos((verify_time / sample_size).try_into().unwrap())
+        );
+    }
+
+    #[test]
+    // Tests hash to field using FFI APIs
+    fn test_seeded_keygen_stateless_ffi() {
+        // We create a RLN instance
+        let rln_pointer = create_rln_instance();
+
+        // We generate a new identity pair from an input seed
+        let seed_bytes: &[u8] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+        let input_buffer = &Buffer::from(seed_bytes);
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success = seeded_key_gen(rln_pointer, input_buffer, output_buffer.as_mut_ptr());
+        assert!(success, "seeded key gen call failed");
+        let output_buffer = unsafe { output_buffer.assume_init() };
+        let result_data = <&[u8]>::from(&output_buffer).to_vec();
+        let (identity_secret_hash, read) = bytes_le_to_fr(&result_data);
+        let (id_commitment, _) = bytes_le_to_fr(&result_data[read..].to_vec());
+
+        // We check against expected values
+        let expected_identity_secret_hash_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        );
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0xbf16d2b5c0d6f9d9d561e05bfca16a81b4b873bb063508fae360d8c74cef51f",
+            16,
+        );
+
+        assert_eq!(
+            identity_secret_hash,
+            expected_identity_secret_hash_seed_bytes.unwrap()
+        );
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes.unwrap());
+    }
+
+    #[test]
+    // Tests hash to field using FFI APIs
+    fn test_seeded_extended_keygen_stateless_ffi() {
+        // We create a RLN instance
+        let rln_pointer = create_rln_instance();
+
+        // We generate a new identity tuple from an input seed
+        let seed_bytes: &[u8] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
+        let input_buffer = &Buffer::from(seed_bytes);
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success =
+            seeded_extended_key_gen(rln_pointer, input_buffer, output_buffer.as_mut_ptr());
+        assert!(success, "seeded key gen call failed");
+        let output_buffer = unsafe { output_buffer.assume_init() };
+        let result_data = <&[u8]>::from(&output_buffer).to_vec();
+        let (identity_trapdoor, identity_nullifier, identity_secret_hash, id_commitment) =
+            deserialize_identity_tuple(result_data);
+
+        // We check against expected values
+        let expected_identity_trapdoor_seed_bytes = str_to_fr(
+            "0x766ce6c7e7a01bdf5b3f257616f603918c30946fa23480f2859c597817e6716",
+            16,
+        );
+        let expected_identity_nullifier_seed_bytes = str_to_fr(
+            "0x1f18714c7bc83b5bca9e89d404cf6f2f585bc4c0f7ed8b53742b7e2b298f50b4",
+            16,
+        );
+        let expected_identity_secret_hash_seed_bytes = str_to_fr(
+            "0x2aca62aaa7abaf3686fff2caf00f55ab9462dc12db5b5d4bcf3994e671f8e521",
+            16,
+        );
+        let expected_id_commitment_seed_bytes = str_to_fr(
+            "0x68b66aa0a8320d2e56842581553285393188714c48f9b17acd198b4f1734c5c",
+            16,
+        );
+
+        assert_eq!(
+            identity_trapdoor,
+            expected_identity_trapdoor_seed_bytes.unwrap()
+        );
+        assert_eq!(
+            identity_nullifier,
+            expected_identity_nullifier_seed_bytes.unwrap()
+        );
+        assert_eq!(
+            identity_secret_hash,
+            expected_identity_secret_hash_seed_bytes.unwrap()
+        );
+        assert_eq!(id_commitment, expected_id_commitment_seed_bytes.unwrap());
+    }
+
+    #[test]
+    // Tests hash to field using FFI APIs
+    fn test_hash_to_field_stateless_ffi() {
+        let mut rng = rand::thread_rng();
+        let signal: [u8; 32] = rng.gen();
+
+        // We prepare id_commitment and we set the leaf at provided index
+        let input_buffer = &Buffer::from(signal.as_ref());
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success = ffi_hash(input_buffer, output_buffer.as_mut_ptr());
+        assert!(success, "hash call failed");
+        let output_buffer = unsafe { output_buffer.assume_init() };
+
+        // We read the returned proof and we append proof values for verify
+        let serialized_hash = <&[u8]>::from(&output_buffer).to_vec();
+        let (hash1, _) = bytes_le_to_fr(&serialized_hash);
+
+        let hash2 = hash_to_field(&signal);
+
+        assert_eq!(hash1, hash2);
+    }
+
+    #[test]
+    // Test Poseidon hash FFI
+    fn test_poseidon_hash_stateless_ffi() {
+        // generate random number between 1..ROUND_PARAMS.len()
+        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).unwrap();
+        let input_buffer = &Buffer::from(inputs_ser.as_ref());
+
+        let expected_hash = utils_poseidon_hash(inputs.as_ref());
+
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success = ffi_poseidon_hash(input_buffer, output_buffer.as_mut_ptr());
+        assert!(success, "poseidon hash call failed");
+
+        let output_buffer = unsafe { output_buffer.assume_init() };
+        let result_data = <&[u8]>::from(&output_buffer).to_vec();
+        let (received_hash, _) = bytes_le_to_fr(&result_data);
+
+        assert_eq!(received_hash, expected_hash);
+    }
+}

rln/tests/protocol.rs

@@ -1,8 +1,8 @@
 #[cfg(test)]
 mod test {
     use ark_ff::BigInt;
-    use rln::circuit::zkey_from_folder;
-    use rln::circuit::{circom_from_folder, vk_from_folder, Fr, TEST_TREE_HEIGHT};
+    use rln::circuit::{graph_from_folder, zkey_from_folder};
+    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
     use rln::hashers::{hash_to_field, poseidon_hash};
     use rln::poseidon_tree::PoseidonTree;
     use rln::protocol::*;
@@ -127,10 +127,9 @@ mod 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().unwrap();
-        let verification_key = vk_from_folder().unwrap();
-        let builder = circom_from_folder().unwrap();
-
+        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();
@@ -138,7 +137,7 @@ mod test {
         assert_eq!(rln_witness_deser, rln_witness);
 
         // Let's generate a zkSNARK proof
-        let proof = generate_proof(builder, &proving_key, &rln_witness_deser).unwrap();
+        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
@@ -156,12 +155,12 @@ mod test {
         assert_eq!(rln_witness_deser, rln_witness);
 
         // We generate all relevant keys
-        let proving_key = zkey_from_folder().unwrap();
-        let verification_key = vk_from_folder().unwrap();
-        let builder = circom_from_folder().unwrap();
+        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(builder, &proving_key, &rln_witness_deser).unwrap();
+        let proof = generate_proof(&proving_key, &rln_witness_deser, &graph_data).unwrap();
 
         let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();
 

rln/tests/public.rs

@@ -1,17 +1,23 @@
 #[cfg(test)]
 mod test {
-    use ark_ff::BigInt;
+    #[cfg(not(feature = "stateless"))]
+    use {
+        ark_ff::BigInt,
+        rln::{circuit::TEST_TREE_HEIGHT, protocol::compute_tree_root},
+    };
+
     use ark_std::{rand::thread_rng, UniformRand};
     use rand::Rng;
-    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
+    use rln::circuit::Fr;
     use rln::hashers::{hash_to_field, poseidon_hash as utils_poseidon_hash, ROUND_PARAMS};
-    use rln::protocol::{compute_tree_root, deserialize_identity_tuple};
+    use rln::protocol::deserialize_identity_tuple;
     use rln::public::{hash as public_hash, poseidon_hash as public_poseidon_hash, RLN};
     use rln::utils::*;
     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;

utils/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "zerokit_utils"
-version = "0.5.0"
+version = "0.5.2"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Various utilities for Zerokit"
@@ -12,21 +12,23 @@ repository = "https://github.com/vacp2p/zerokit"
 bench = false
 
 [dependencies]
-ark-ff = { version = "=0.4.1", default-features = false, features = ["asm"] }
-num-bigint = { version = "=0.4.3", default-features = false, features = ["rand"] }
-color-eyre = "=0.6.2"
-pmtree = { package = "vacp2p_pmtree", version = "=2.0.2", optional = true}
-sled = "=0.34.7"
-serde = "=1.0.163"
+ark-ff = { version = "0.5.0", features = ["asm"] }
+num-bigint = { version = "0.4.6", default-features = false, features = [
+    "rand",
+] }
+color-eyre = "0.6.2"
+pmtree = { package = "vacp2p_pmtree", version = "=2.0.2", optional = true }
+sled = "0.34.7"
+serde = "1.0"
 lazy_static = "1.4.0"
 hex = "0.4"
 
 [dev-dependencies]
-ark-bn254 = "=0.4.0"
-num-traits = "=0.2.15"
-hex-literal = "=0.3.4"
-tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
-criterion = { version = "=0.4.0", features = ["html_reports"] }
+ark-bn254 = { version = "0.5.0", features = ["std"] }
+num-traits = "0.2.19"
+hex-literal = "0.3.4"
+tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+criterion = { version = "0.4.0", features = ["html_reports"] }
 
 [features]
 default = ["parallel"]

utils/README.md

@@ -1,15 +1,77 @@
-# Utils crate
+# Zerokit Utils Crate
 
-## Building
+[![Crates.io](https://img.shields.io/crates/v/zerokit_utils.svg)](https://crates.io/crates/zerokit_utils)
 
-1. `cargo build`
+Cryptographic primitives for zero-knowledge applications, featuring efficient Merkle tree implementations and a Poseidon hash function.
 
-## Testing
+## Overview
 
-1. `cargo test`
+This crate provides core cryptographic components optimized for zero-knowledge proof systems:
 
-## Benchmarking
+1. Multiple Merkle tree implementations with different space/time tradeoffs
+2. A Poseidon hash implementation
 
-1. `cargo bench`
+## Merkle Tree Implementations
 
-To view the results of the benchmark, open the `target/criterion/report/index.html` file generated after the bench
+The crate supports two interchangeable Merkle tree implementations:
+
+- **FullMerkleTree**
+  - Stores each tree node in memory
+- **OptimalMerkleTree**
+  - Only stores nodes used to prove accumulation of set leaves
+
+## Poseidon Hash Implementation
+
+This crate provides an implementation to compute the Poseidon hash round constants and MDS matrices:
+
+- **Customizable parameters**: Supports different security levels and input sizes
+- **Arkworks-friendly**: Adapted to work over arkworks field traits and custom data structures
+
+### Security Note
+
+The MDS matrices are generated iteratively using the Grain LFSR until certain criteria are met.
+According to the paper, such matrices must respect specific conditions which are checked by 3 different algorithms in the reference implementation.
+
+These validation algorithms are not currently implemented in this crate.
+For the hardcoded parameters, the first random matrix generated satisfies these conditions.
+If using different parameters, you should check against the reference implementation how many matrices are generated before outputting the correct one,
+and pass this number to the `skip_matrices` parameter of the `find_poseidon_ark_and_mds` function.
+
+## Installation
+
+Add Zerokit Utils to your Rust project:
+
+```toml
+[dependencies]
+zerokit-utils = "0.5.1"
+```
+
+## Performance Considerations
+
+- **FullMerkleTree**: Use when memory is abundant and operation speed is critical
+- **OptimalMerkleTree**: Use when memory efficiency is more important than raw speed
+- **Poseidon**: Offers a good balance between security and performance for ZK applications
+
+## Building and Testing
+
+```bash
+# Build the crate
+cargo build
+
+# Run tests
+cargo test
+
+# Run benchmarks
+cargo bench
+```
+
+To view the results of the benchmark, open the `target/criterion/report/index.html` file generated after the bench
+
+## Acknowledgements
+
+- The Merkle tree implementations are adapted from:
+  - [kilic/rln](https://github.com/kilic/rln/blob/master/src/merkle.rs)
+  - [worldcoin/semaphore-rs](https://github.com/worldcoin/semaphore-rs/blob/d462a4372f1fd9c27610f2acfe4841fab1d396aa/src/merkle_tree.rs)
+
+- The Poseidon implementation references:
+  - [Poseidon reference implementation](https://extgit.iaik.tugraz.at/krypto/hadeshash/-/blob/master/code/generate_parameters_grain.sage)

utils/src/merkle_tree/full_merkle_tree.rs

@@ -8,7 +8,7 @@ use std::{
 };
 
 ////////////////////////////////////////////////////////////
-/// Full Merkle Tree Implementation
+///// Full Merkle Tree Implementation
 ////////////////////////////////////////////////////////////
 
 /// Merkle tree with all leaf and intermediate hashes stored
@@ -257,7 +257,7 @@ where
         Ok(())
     }
 
-    // Computes a merkle proof the the leaf at the specified index
+    // Computes a merkle proof the leaf at the specified index
     fn proof(&self, leaf: usize) -> Result<FullMerkleProof<H>> {
         if leaf >= self.capacity() {
             return Err(Report::msg("index exceeds set size"));

utils/src/merkle_tree/optimal_merkle_tree.rs

@@ -6,7 +6,7 @@ use std::str::FromStr;
 use std::{cmp::max, fmt::Debug};
 
 ////////////////////////////////////////////////////////////
-/// Optimal Merkle Tree Implementation
+///// Optimal Merkle Tree Implementation
 ////////////////////////////////////////////////////////////
 
 /// The Merkle tree structure
@@ -55,7 +55,9 @@ impl FromStr for OptimalMerkleConfig {
     }
 }
 
-/// Implementations
+////////////////////////////////////////////////////////////
+///// Implementations
+////////////////////////////////////////////////////////////
 
 impl<H: Hasher> ZerokitMerkleTree for OptimalMerkleTree<H>
 where
@@ -223,7 +225,7 @@ where
         Ok(())
     }
 
-    // Computes a merkle proof the the leaf at the specified index
+    // Computes a merkle proof the leaf at the specified index
     fn proof(&self, index: usize) -> Result<Self::Proof> {
         if index >= self.capacity() {
             return Err(Report::msg("index exceeds set size"));