release v0.8.0 (#315)

Co-authored-by: Ekaterina Broslavskaya <seemenkina@gmail.com>

.github/labels.yml

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

.github/workflows/ci.yml

@@ -24,8 +24,8 @@ jobs:
   utils-test:
     strategy:
       matrix:
-        platform: [ ubuntu-latest, macos-latest ]
-        crate: [ utils ]
+        platform: [ubuntu-latest, macos-latest]
+        crate: [utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
@@ -50,9 +50,9 @@ jobs:
   rln-test:
     strategy:
       matrix:
-        platform: [ ubuntu-latest, macos-latest ]
-        crate: [ rln ]
-        feature: [ "default", "arkzkey", "stateless" ]
+        platform: [ubuntu-latest, macos-latest]
+        crate: [rln]
+        feature: ["default", "arkzkey", "stateless"]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
@@ -71,17 +71,23 @@ jobs:
         run: make installdeps
       - name: cargo-make test
         run: |
-          cargo make test_${{ matrix.feature }} --release
+          if [ ${{ matrix.feature }} == default ]; then
+            cargo make test --release
+          else
+            cargo make test_${{ matrix.feature }} --release
+          fi
         working-directory: ${{ matrix.crate }}
 
-  rln-wasm:
+  rln-wasm-test:
     strategy:
       matrix:
-        platform: [ ubuntu-latest, macos-latest ]
+        platform: [ubuntu-latest, macos-latest]
+        crate: [rln-wasm]
+        feature: ["default", "arkzkey"]
     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: Install stable toolchain
@@ -93,19 +99,77 @@ jobs:
       - uses: Swatinem/rust-cache@v2
       - 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 build
+        run: |
+          if [ ${{ matrix.feature }} == default ]; then
+            cargo make build
+          else
+            cargo make build_${{ matrix.feature }}
+          fi
+        working-directory: ${{ matrix.crate }}
+      - 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 }}
+      - name: cargo-make test browser
+        run: |
+          if [ ${{ matrix.feature }} == default ]; then
+            cargo make test_browser --release
+          else
+            cargo make test_browser_${{ matrix.feature }} --release
+          fi
+        working-directory: ${{ matrix.crate }}
+
+  # rln-wasm-multihread-test:
+  #   strategy:
+  #     matrix:
+  #       platform: [ubuntu-latest, macos-latest]
+  #       crate: [rln-wasm]
+  #       feature: ["multithread", "multithread_arkzkey"]
+  #   runs-on: ${{ matrix.platform }}
+  #   timeout-minutes: 60
+
+  #   name: test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
+  #   steps:
+  #     - uses: actions/checkout@v3
+  #     - name: Install nightly toolchain
+  #       uses: actions-rs/toolchain@v1
+  #       with:
+  #         profile: minimal
+  #         toolchain: nightly
+  #         override: true
+  #         components: rust-src
+  #         target: wasm32-unknown-unknown
+  #     - uses: Swatinem/rust-cache@v2
+  #     - name: Install Dependencies
+  #       run: make installdeps
+  #     - name: cargo-make build
+  #       run: |
+  #         if [ ${{ matrix.feature }} == default ]; then
+  #           cargo make build
+  #         else
+  #           cargo make build_${{ matrix.feature }}
+  #         fi
+  #       working-directory: ${{ matrix.crate }}
+  #     - 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, rln-wasm, utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
@@ -130,11 +194,8 @@ jobs:
       - name: cargo clippy
         if: success() || failure()
         run: |
-          cargo clippy --release -- -D warnings
+          cargo clippy --release
         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-utils:
     # run only in pull requests
@@ -142,12 +203,12 @@ jobs:
     strategy:
       matrix:
         # we run benchmark tests only on ubuntu
-        platform: [ ubuntu-latest ]
-        crate: [ utils ]
+        platform: [ubuntu-latest]
+        crate: [utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: benchmark - ${{ matrix.platform }} - ${{ matrix.crate }}
+    name: benchmark - ${{ matrix.crate }} - ${{ matrix.platform }}
     steps:
       - name: Checkout sources
         uses: actions/checkout@v3
@@ -163,13 +224,13 @@ jobs:
     strategy:
       matrix:
         # we run benchmark tests only on ubuntu
-        platform: [ ubuntu-latest ]
-        crate: [ rln ]
-        feature: [ "default", "arkzkey" ]
+        platform: [ubuntu-latest]
+        crate: [rln]
+        feature: ["default", "arkzkey"]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: benchmark - ${{ matrix.platform }} - ${{ matrix.crate }} - ${{ matrix.feature }}
+    name: benchmark - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
     steps:
       - name: Checkout sources
         uses: actions/checkout@v3
@@ -178,4 +239,4 @@ jobs:
         with:
           branchName: ${{ github.base_ref }}
           cwd: ${{ matrix.crate }}
-          features: ${{ matrix.feature }}
+          features: ${{ matrix.feature }}

.github/workflows/nightly-release.yml

@@ -12,7 +12,7 @@ jobs:
         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
@@ -33,7 +33,7 @@ jobs:
         run: make installdeps
       - name: cross build
         run: |
-          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace --exclude rln-wasm ${{ matrix.cargo_args }}
+          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/
@@ -72,7 +72,7 @@ jobs:
         run: make installdeps
       - name: cross build
         run: |
-          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace --exclude rln-wasm ${{ matrix.cargo_args }}
+          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/
@@ -99,8 +99,6 @@ jobs:
       - 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

.gitignore

@@ -3,12 +3,15 @@
 *.log
 tmp/
 rln/pmtree_db
+rln-cli/database
 
 # Generated by Cargo
 # will have compiled files and executables
 debug/
 target/
-wabt/
+
+# Generated by Nix
+result
 
 # These are backup files generated by rustfmt
 **/*.rs.bk

CHANGELOG.md

@@ -1,3 +1,5 @@
+# CHANGE LOG
+
 ## 2023-02-28 v0.2
 
 This release contains:
@@ -10,7 +12,6 @@ This release contains:
 - Dual License under Apache 2.0 and MIT
 - RLN compiles as a static library, which can be consumed through a C FFI
 
-
 ## 2022-09-19 v0.1
 
 Initial beta release.

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 members = ["rln", "rln-cli", "rln-wasm", "utils"]
-default-members = ["rln", "rln-cli", "utils"]
+default-members = ["rln", "rln-cli", "rln-wasm", "utils"]
 resolver = "2"
 
 # Compilation profile for any non-workspace member.
@@ -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

@@ -1,6 +1,6 @@
-.PHONY: all installdeps build test clean
+.PHONY: all installdeps build test bench clean
 
-all: .pre-build build
+all: installdeps build
 
 .fetch-submodules:
 	@git submodule update --init --recursive
@@ -13,25 +13,27 @@ endif
 
 installdeps: .pre-build
 ifeq ($(shell uname),Darwin)
-# commented due to https://github.com/orgs/Homebrew/discussions/4612
-# @brew update
-	@brew install cmake ninja
+	@brew install cmake ninja binaryen
 else ifeq ($(shell uname),Linux)
-	@sudo apt-get update
-	@sudo apt-get install -y cmake ninja-build
+	@if [ -f /etc/os-release ] && grep -q "ID=nixos" /etc/os-release; then \
+		echo "Detected NixOS, skipping apt-get installation."; \
+	else \
+		sudo apt-get install -y cmake ninja-build binaryen; \
+	fi
 endif
-	@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
-	# 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;
+	@which wasm-pack > /dev/null && wasm-pack --version | grep -q "0.13.1" || cargo install wasm-pack --version=0.13.1
+	@which wasm-bindgen > /dev/null && wasm-bindgen --version | grep -q "0.2.100" || cargo install wasm-bindgen-cli --version=0.2.100
+	@test -s "$$HOME/.nvm/nvm.sh" || curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.2/install.sh | bash
+	@bash -c '. "$$HOME/.nvm/nvm.sh"; [ "$$(node -v 2>/dev/null)" = "v22.14.0" ] || nvm install 22.14.0; nvm use 22.14.0; nvm alias default 22.14.0'
 
-build: .pre-build
+build: installdeps
 	@cargo make build
 
-test: .pre-build
+test: build
 	@cargo make test
 
+bench: build
+	@cargo make bench
+
 clean:
 	@cargo clean

README.md

@@ -1,45 +1,87 @@
 # 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
+#### Use Nix to install dependencies
+
+```bash
+nix develop
+```
+
+### 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
+```

flake.lock

@@ -0,0 +1,48 @@
+{
+  "nodes": {
+    "nixpkgs": {
+      "locked": {
+        "lastModified": 1740603184,
+        "narHash": "sha256-t+VaahjQAWyA+Ctn2idyo1yxRIYpaDxMgHkgCNiMJa4=",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f44bd8ca21e026135061a0a57dcf3d0775b67a49",
+        "type": "github"
+      },
+      "original": {
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "f44bd8ca21e026135061a0a57dcf3d0775b67a49",
+        "type": "github"
+      }
+    },
+    "root": {
+      "inputs": {
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
+      }
+    },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1748399823,
+        "narHash": "sha256-kahD8D5hOXOsGbNdoLLnqCL887cjHkx98Izc37nDjlA=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "d68a69dc71bc19beb3479800392112c2f6218159",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}

flake.nix

@@ -0,0 +1,71 @@
+{
+  description = "A flake for building zerokit";
+
+  inputs = {
+    # Version 24.11
+    nixpkgs.url = "github:NixOS/nixpkgs?rev=f44bd8ca21e026135061a0a57dcf3d0775b67a49";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs = { self, nixpkgs, rust-overlay }:
+    let
+      stableSystems = [
+        "x86_64-linux" "aarch64-linux"
+        "x86_64-darwin" "aarch64-darwin"
+        "x86_64-windows" "i686-linux"
+        "i686-windows"
+      ];
+      forAllSystems = nixpkgs.lib.genAttrs stableSystems;
+      overlays = [
+        (import rust-overlay)
+        (f: p: { inherit rust-overlay; })
+      ];
+      pkgsFor = forAllSystems (system: import nixpkgs { inherit system overlays; });
+    in rec
+    {
+      packages = forAllSystems (system: let
+        pkgs = pkgsFor.${system};
+        buildPackage = pkgs.callPackage ./nix/default.nix;
+        buildRln = (buildPackage { src = self; project = "rln"; }).override;
+      in rec {
+        rln = buildRln {
+          features = "arkzkey";
+        };
+
+        rln-linux-arm64 = buildRln {
+          target-platform = "aarch64-multiplatform";
+          rust-target = "aarch64-unknown-linux-gnu";
+        };
+
+        rln-android-arm64 = buildRln {
+          target-platform = "aarch64-android-prebuilt";
+          rust-target = "aarch64-linux-android";
+        };
+
+        rln-ios-arm64 = buildRln {
+          target-platform = "aarch64-darwin";
+          rust-target = "aarch64-apple-ios";
+        };
+
+        # TODO: Remove legacy name for RLN android library
+        zerokit-android-arm64 = rln-android-arm64;
+
+        default = rln;
+      });
+
+      devShells = forAllSystems (system: let
+        pkgs = pkgsFor.${system};
+      in {
+        default = pkgs.mkShell {
+          buildInputs = with pkgs; [
+            git cmake cargo-make rustup
+            binaryen ninja gnuplot
+            rust-bin.stable.latest.default
+          ];
+        };
+      });
+    };
+}

nix/default.nix

@@ -0,0 +1,62 @@
+{
+  pkgs,
+  rust-overlay,
+  project,
+  src ? ../.,
+  release ? true,
+  features ? "arkzkey",
+  target-platform ? null,
+  rust-target ? null,
+}:
+
+let
+  # Use cross-compilation if target-platform is specified.
+  targetPlatformPkgs = if target-platform != null
+    then pkgs.pkgsCross.${target-platform}
+    else pkgs;
+
+  rust-bin = rust-overlay.lib.mkRustBin { } targetPlatformPkgs.buildPackages;
+
+  # Use Rust and Cargo versions from rust-overlay.
+  rustPlatform = targetPlatformPkgs.makeRustPlatform {
+    cargo = rust-bin.stable.latest.minimal;
+    rustc = rust-bin.stable.latest.minimal;
+  };
+in rustPlatform.buildRustPackage {
+  pname = "zerokit";
+  version = if src ? rev then src.rev else "nightly";
+
+  # Improve caching of sources
+  src = builtins.path { path = src; name = "zerokit"; };
+
+  cargoLock = {
+    lockFile = ../Cargo.lock;
+    allowBuiltinFetchGit = true;
+  };
+
+  doCheck = false;
+
+  CARGO_HOME = "/tmp";
+
+  buildPhase = ''
+    cargo build --lib \
+      ${if release             then "--release" else ""} \
+      ${if rust-target != null then "--target=${rust-target}" else ""} \
+      ${if features != null    then "--features=${features}" else ""} \
+      --manifest-path ${project}/Cargo.toml
+  '';
+
+  installPhase = ''
+    mkdir -p $out/
+    for file in $(find target -name 'librln.*' | grep -v deps/); do
+      mkdir -p $out/$(dirname $file)
+      cp -r $file $out/$file
+    done
+  '';
+
+
+  meta = with pkgs.lib; {
+    description = "Zerokit";
+    license = licenses.mit;
+  };
+}

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", default-features = true, features = ["arkzkey"] }
-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 }
+zerokit_utils = { path = "../utils" }
+clap = { version = "4.5.38", features = ["cargo", "derive", "env"] }
+color-eyre = "0.6.4"
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
+
+[features]
+default = []
+arkzkey = ["rln/arkzkey"]
+stateless = ["rln/stateless"]

rln-cli/Makefile.toml

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

rln-cli/README.md

@@ -0,0 +1,170 @@
+# 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, Report, 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(Report::new(err)),
+        }
+        Ok(())
+    }
+
+    fn handle_duplicate_message_id(
+        &mut self,
+        previous_proof: Vec<u8>,
+        current_proof: Vec<u8>,
+    ) -> Result<()> {
+        let x = &current_proof[192..224];
+        let y = &current_proof[224..256];
+
+        let prev_x = &previous_proof[192..224];
+        let prev_y = &previous_proof[224..256];
+        if x == prev_x && y == prev_y {
+            return Err(eyre!("this exact message and signal has already been sent"));
+        }
+
+        let mut proof1 = Cursor::new(previous_proof);
+        let mut proof2 = Cursor::new(current_proof);
+        let mut output = Cursor::new(Vec::new());
+
+        match self
+            .rln
+            .recover_id_secret(&mut proof1, &mut proof2, &mut output)
+        {
+            Ok(_) => {
+                let output_data = output.into_inner();
+                let (leaked_identity_secret_hash, _) = 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 +1,314 @@
+#![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 x = hash_to_field(signal.as_bytes());
+
+        let rln_witness = rln_witness_from_values(
+            identity.identity_secret_hash,
+            &merkle_proof,
+            x,
+            external_nullifier,
+            Fr::from(MESSAGE_LIMIT),
+            Fr::from(message_id),
+        )?;
+
+        let serialized = serialize_witness(&rln_witness)?;
+        let mut input_buffer = Cursor::new(serialized);
+        let mut output_buffer = Cursor::new(Vec::new());
+
+        self.rln
+            .generate_rln_proof_with_witness(&mut input_buffer, &mut output_buffer)?;
+
+        println!("Proof generated successfully:");
+        println!("+ User Index: {user_index}");
+        println!("+ Message ID: {message_id}");
+        println!("+ Signal: {signal}");
+
+        Ok(output_buffer.into_inner())
+    }
+
+    fn verify_proof(&mut self, proof_data: Vec<u8>, signal: &str) -> Result<()> {
+        let proof_with_signal = prepare_verify_input(proof_data.clone(), signal.as_bytes());
+        let mut input_buffer = Cursor::new(proof_with_signal);
+
+        let root = self.tree.root();
+        let roots_serialized = fr_to_bytes_le(&root);
+        let mut roots_buffer = Cursor::new(roots_serialized);
+
+        match self
+            .rln
+            .verify_with_roots(&mut input_buffer, &mut roots_buffer)
+        {
+            Ok(true) => {
+                let nullifier = &proof_data[256..288];
+                let nullifier_key: [u8; 32] = nullifier.try_into()?;
+
+                if let Some(previous_proof) = self.used_nullifiers.get(&nullifier_key) {
+                    self.handle_duplicate_message_id(previous_proof.clone(), proof_data)?;
+                    return Ok(());
+                }
+                self.used_nullifiers.insert(nullifier_key, proof_data);
+                println!("Message verified and accepted");
+            }
+            Ok(false) => {
+                println!("Verification failed: message_id must be unique within the epoch and satisfy 0 <= message_id < MESSAGE_LIMIT: {MESSAGE_LIMIT}");
+            }
+            Err(err) => return Err(err.into()),
+        }
+        Ok(())
+    }
+
+    fn handle_duplicate_message_id(
+        &mut self,
+        previous_proof: Vec<u8>,
+        current_proof: Vec<u8>,
+    ) -> Result<()> {
+        let x = &current_proof[192..224];
+        let y = &current_proof[224..256];
+
+        let prev_x = &previous_proof[192..224];
+        let prev_y = &previous_proof[224..256];
+        if x == prev_x && y == prev_y {
+            return Err(eyre!("this exact message and signal has already been sent"));
+        }
+
+        let mut proof1 = Cursor::new(previous_proof);
+        let mut proof2 = Cursor::new(current_proof);
+        let mut output = Cursor::new(Vec::new());
+
+        match self
+            .rln
+            .recover_id_secret(&mut proof1, &mut proof2, &mut output)
+        {
+            Ok(_) => {
+                let output_data = output.into_inner();
+                let (leaked_identity_secret_hash, _) = 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.arkvkey"];
+            let filenames = ["rln_final.arkzkey", "graph.bin"];
             #[cfg(not(feature = "arkzkey"))]
-            let filenames = ["rln.wasm", "rln_final.zkey", "verification_key.arkvkey"];
+            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

@@ -1,6 +1,7 @@
+use std::io::Cursor;
+
 use color_eyre::Result;
 use rln::public::RLN;
-use std::fs::File;
 
 use crate::config::{Config, InnerConfig};
 
@@ -12,9 +13,8 @@ pub(crate) struct State {
 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/Cargo.toml

@@ -1,39 +1,46 @@
 [package]
 name = "rln-wasm"
-version = "0.0.13"
+version = "0.2.0"
 edition = "2021"
 license = "MIT or Apache2"
 
 [lib]
 crate-type = ["cdylib", "rlib"]
-
-[features]
-default = ["console_error_panic_hook"]
+required-features = ["stateless"]
 
 [dependencies]
-rln = { path = "../rln", default-features = false, features = [
-    "wasm",
-    "stateless",
-] }
-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"
+rln = { path = "../rln", version = "0.8.0", default-features = false }
+zerokit_utils = { path = "../utils", version = "0.6.0" }
 
-# The `console_error_panic_hook` crate provides better debugging of panics by
+num-bigint = { version = "0.4.6", default-features = false }
+js-sys = "0.3.77"
+wasm-bindgen = "0.2.100"
+serde-wasm-bindgen = "0.6.5"
+wasm-bindgen-rayon = { version = "1.2.0", optional = true }
+
+# The `console_error_panic_xhook` crate provides better debugging of panics by
 # logging them with `console.error`. This is great for development, but requires
 # all the `std::fmt` and `std::panicking` infrastructure, so isn't great for
 # code size when deploying.
 console_error_panic_hook = { version = "0.1.7", optional = true }
-zerokit_utils = { version = "0.5.1", path = "../utils" }
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+getrandom = { version = "0.2.16", features = ["js"] }
 
 [dev-dependencies]
-wasm-bindgen-test = "0.3.13"
-wasm-bindgen-futures = "0.4.33"
+serde_json = "1.0"
+wasm-bindgen-test = "0.3.50"
+wasm-bindgen-futures = "0.4.50"
+
+[dev-dependencies.web-sys]
+version = "0.3.77"
+features = ["Window", "Navigator"]
+
+[features]
+default = ["console_error_panic_hook"]
+stateless = ["rln/stateless"]
+arkzkey = ["rln/arkzkey"]
+multithread = ["wasm-bindgen-rayon"]
+
+[package.metadata.docs.rs]
+all-features = true

rln-wasm/Makefile.toml

@@ -1,23 +1,237 @@
-[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"]
+dependencies = ["pack_build", "pack_rename", "pack_resize"]
 
-[tasks.post-build]
-command = "wasm-strip"
-args = ["./pkg/rln_wasm_bg.wasm"]
+[tasks.build_arkzkey]
+clear = true
+dependencies = ["pack_build_arkzkey", "pack_rename", "pack_resize"]
+
+[tasks.build_multithread]
+clear = true
+dependencies = [
+    "pack_build_multithread",
+    "post_build_multithread",
+    "pack_rename",
+    "pack_resize",
+]
+
+[tasks.build_multithread_arkzkey]
+clear = true
+dependencies = [
+    "pack_build_multithread_arkzkey",
+    "post_build_multithread",
+    "pack_rename",
+    "pack_resize",
+]
+
+[tasks.pack_build]
+command = "wasm-pack"
+args = [
+    "build",
+    "--release",
+    "--target",
+    "web",
+    "--scope",
+    "waku",
+    "--features",
+    "stateless",
+]
+
+[tasks.pack_build_arkzkey]
+command = "wasm-pack"
+args = [
+    "build",
+    "--release",
+    "--target",
+    "web",
+    "--scope",
+    "waku",
+    "--features",
+    "stateless,arkzkey",
+]
+
+[tasks.pack_build_multithread]
+command = "env"
+args = [
+    "RUSTFLAGS=-C target-feature=+atomics,+bulk-memory,+mutable-globals",
+    "rustup",
+    "run",
+    "nightly",
+    "wasm-pack",
+    "build",
+    "--release",
+    "--target",
+    "web",
+    "--scope",
+    "waku",
+    "--features",
+    "stateless,multithread",
+    "-Z",
+    "build-std=panic_abort,std",
+]
+
+[tasks.pack_build_multithread_arkzkey]
+command = "env"
+args = [
+    "RUSTFLAGS=-C target-feature=+atomics,+bulk-memory,+mutable-globals",
+    "rustup",
+    "run",
+    "nightly",
+    "wasm-pack",
+    "build",
+    "--release",
+    "--target",
+    "web",
+    "--scope",
+    "waku",
+    "--features",
+    "stateless,multithread,arkzkey",
+    "-Z",
+    "build-std=panic_abort,std",
+]
+
+[tasks.post_build_multithread]
+script = '''
+wasm-bindgen --target web --split-linked-modules --out-dir ./pkg ../target/wasm32-unknown-unknown/release/rln_wasm.wasm && \
+find ./pkg/snippets -name "workerHelpers.worker.js" -exec sed -i.bak 's|from '\''\.\.\/\.\.\/\.\.\/'\'';|from "../../../rln_wasm.js";|g' {} \; -exec rm -f {}.bak \; && \
+find ./pkg/snippets -name "workerHelpers.worker.js" -exec sed -i.bak 's|await initWbg(module, memory);|await initWbg({ module, memory });|g' {} \; -exec rm -f {}.bak \;
+'''
+
+[tasks.pack_rename]
+script = "sed -i.bak 's/rln-wasm/zerokit-rln-wasm/g' pkg/package.json && rm pkg/package.json.bak"
+
+[tasks.pack_resize]
+command = "wasm-opt"
+args = [
+    "pkg/rln_wasm_bg.wasm",
+    "-Oz",
+    "--strip-debug",
+    "--strip-dwarf",
+    "--remove-unused-module-elements",
+    "--vacuum",
+    "-o",
+    "pkg/rln_wasm_bg.wasm",
+]
 
 [tasks.test]
 command = "wasm-pack"
-args = ["test", "--release", "--node"]
+args = [
+    "test",
+    "--release",
+    "--node",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--features",
+    "stateless",
+    "--",
+    "--nocapture",
+]
 dependencies = ["build"]
 
+[tasks.test_arkzkey]
+command = "wasm-pack"
+args = [
+    "test",
+    "--release",
+    "--node",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--features",
+    "stateless,arkzkey",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build_arkzkey"]
+
+[tasks.test_browser]
+command = "wasm-pack"
+args = [
+    "test",
+    "--release",
+    "--chrome",
+    # "--firefox",
+    # "--safari",
+    "--headless",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--features",
+    "stateless",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build"]
+
+[tasks.test_browser_arkzkey]
+command = "wasm-pack"
+args = [
+    "test",
+    "--release",
+    "--chrome",
+    # "--firefox",
+    # "--safari",
+    "--headless",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--features",
+    "stateless,arkzkey",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build_arkzkey"]
+
+[tasks.test_multithread]
+command = "env"
+args = [
+    "RUSTFLAGS=-C target-feature=+atomics,+bulk-memory,+mutable-globals",
+    "rustup",
+    "run",
+    "nightly",
+    "wasm-pack",
+    "test",
+    "--release",
+    "--chrome",
+    # "--firefox",
+    # "--safari",
+    "--headless",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--features",
+    "stateless,multithread",
+    "-Z",
+    "build-std=panic_abort,std",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build_multithread"]
+
+[tasks.test_multithread_arkzkey]
+command = "env"
+args = [
+    "RUSTFLAGS=-C target-feature=+atomics,+bulk-memory,+mutable-globals",
+    "rustup",
+    "run",
+    "nightly",
+    "wasm-pack",
+    "test",
+    "--release",
+    "--chrome",
+    # "--firefox",
+    # "--safari",
+    "--headless",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--features",
+    "stateless,multithread,arkzkey",
+    "-Z",
+    "build-std=panic_abort,std",
+    "--",
+    "--nocapture",
+]
+dependencies = ["build_multithread_arkzkey"]
+
+[tasks.bench]
+disabled = true
+
 [tasks.login]
 command = "wasm-pack"
 args = ["login"]
@@ -25,7 +239,3 @@ 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 +1,171 @@
 # 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`
+[![npm version](https://badge.fury.io/js/@waku%2Fzerokit-rln-wasm.svg)](https://badge.fury.io/js/@waku%2Fzerokit-rln-wasm)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
+
+The Zerokit RLN WASM Module provides WebAssembly bindings for working with
+Rate-Limiting Nullifier [RLN](https://rfc.vac.dev/spec/32/) zkSNARK proofs and primitives.
+This module is used by [waku-org/js-rln](https://github.com/waku-org/js-rln/) to enable
+RLN functionality in JavaScript/TypeScript applications.
+
+## Install Dependencies
+
+> [!NOTE]
+> This project requires the following tools:
+>
+> - `wasm-pack` - for compiling Rust to WebAssembly
+> - `cargo-make` - for running build commands
+> - `nvm` - to install and manage Node.js
+>
+> Ensure all dependencies are installed before proceeding.
+
+### Manually
+
+#### Install `wasm-pack`
+
+```bash
+cargo install wasm-pack --version=0.13.1
 ```
+
+#### Install `cargo-make`
+
+```bash
 cargo install cargo-make
 ```
 
-OR
+#### Install `Node.js`
 
+If you don't have `nvm` (Node Version Manager), install it by following
+the [installation instructions](https://github.com/nvm-sh/nvm?tab=readme-ov-file#install--update-script).
+
+After installing `nvm`, install and use Node.js `v22.14.0`:
+
+```bash
+nvm install 22.14.0
+nvm use 22.14.0
+nvm alias default 22.14.0
 ```
+
+If you already have Node.js installed,
+check your version with `node -v` command — the version must be strictly greater than 22.
+
+### Or install everything
+
+You can run the following command from the root of the repository to install all required dependencies for `zerokit`
+
+```bash
 make installdeps
 ```
-3. Compile zerokit for `wasm32-unknown-unknown`:
-```
+
+## Building the library
+
+First, navigate to the rln-wasm directory:
+
+```bash
 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
+Compile zerokit for `wasm32-unknown-unknown`:
+
+```bash
+cargo make build
 ```
-cd rln-wasm
+
+Or compile with the **arkzkey** feature enabled
+
+```bash
+cargo make build_arkzkey
+```
+
+## Running tests and benchmarks
+
+```bash
 cargo make test
 ```
 
-## Publishing a npm package
+Or test with the **arkzkey** feature enabled
+
+```bash
+cargo make test_arkzkey
+```
+
+If you want to run the tests in browser headless mode, you can use the following command:
+
+```bash
+cargo make test_browser
+cargo make test_browser_arkzkey
+```
+
+## Parallel computation
+
+The library supports parallel computation using the `wasm-bindgen-rayon` crate,
+enabling multi-threaded execution in the browser.
+
+> [!NOTE]
+> Parallel support is not enabled by default due to WebAssembly and browser limitations. \
+> Compiling this feature requires `nightly` Rust and the `wasm-bindgen-cli` tool.
+
+### Build Setup
+
+#### Install `nightly` Rust
+
+```bash
+rustup install nightly
+```
+
+#### Install `wasm-bindgen-cli`
+
+```bash
+cargo install wasm-bindgen-cli --version=0.2.100
+```
+
+### Build Commands
+
+To enable parallel computation for WebAssembly threads, you can use the following command:
+
+```bash
+cargo make build_multithread
+```
+
+Or with the **arkzkey** feature enabled:
+
+```bash
+cargo make build_multithread_arkzkey
+```
+
+### WebAssembly Threading Support
+
+Most modern browsers support WebAssembly threads,
+but they require the following headers to enable `SharedArrayBuffer`, which is necessary for multithreading:
+
+- Cross-Origin-Opener-Policy: same-origin
+- Cross-Origin-Embedder-Policy: require-corp
+
+Without these, the application will fall back to single-threaded mode.
+
+## Feature detection
+
+If you're targeting [older browser versions that didn't support WebAssembly threads yet](https://webassembly.org/roadmap/),
+you'll likely want to create two builds - one with thread support and one without -
+and use feature detection to choose the right one on the JavaScript side.
+
+You can use [wasm-feature-detect](https://github.com/GoogleChromeLabs/wasm-feature-detect)library for this purpose.
+For example, your code might look like this:
+
+```js
+import { threads } from 'wasm-feature-detect';
+
+let wasmPkg;
+
+if (await threads()) {
+  wasmPkg = await import('./pkg-with-threads/index.js');
+  await wasmPkg.default();
+  await wasmPkg.initThreadPool(navigator.hardwareConcurrency);
+} else {
+  wasmPkg = await import('./pkg-without-threads/index.js');
+  await wasmPkg.default();
+}
+
+wasmPkg.nowCallAnyExportedFuncs();
 ```
-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/resources/witness_calculator_browser.js

@@ -0,0 +1,335 @@
+// Browser compatible witness calculator
+(function (global) {
+  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;
+  }
+
+  // Make it globally available
+  global.witnessCalculatorBuilder = builder;
+})(typeof self !== "undefined" ? self : window);

rln-wasm/resources/witness_calculator_node.js

@@ -0,0 +1,325 @@
+// Node.js module compatible witness calculator
+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

@@ -1,16 +1,15 @@
 #![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 std::vec::Vec;
 use wasm_bindgen::prelude::*;
 
-#[wasm_bindgen]
+#[cfg(feature = "multithread")]
+pub use wasm_bindgen_rayon::init_thread_pool;
+
+#[wasm_bindgen(js_name = initPanicHook)]
 pub fn init_panic_hook() {
     console_error_panic_hook::set_once();
 }
@@ -61,24 +60,6 @@ macro_rules! call_with_output_and_error_msg {
     };
 }
 
-// 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)*) => {
         {
@@ -181,19 +162,15 @@ impl<'a> ProcessArg for &'a [u8] {
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[wasm_bindgen(js_name = newRLN)]
-pub fn wasm_new(
-    zkey: Uint8Array,
-    vk: Uint8Array,
-) -> Result<*mut RLNWrapper, String> {
-    let instance = RLN::new_with_params(zkey.to_vec(), vk.to_vec())
-        .map_err(|err| format!("{:#?}", err))?;
+pub fn wasm_new(zkey: Uint8Array) -> Result<*mut RLNWrapper, String> {
+    let instance = RLN::new_with_params(zkey.to_vec()).map_err(|err| format!("{:#?}", err))?;
     let wrapper = RLNWrapper { instance };
     Ok(Box::into_raw(Box::new(wrapper)))
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = RLNWitnessToJson)]
-pub fn rln_witness_to_json(
+#[wasm_bindgen(js_name = rlnWitnessToJson)]
+pub fn wasm_rln_witness_to_json(
     ctx: *mut RLNWrapper,
     serialized_witness: Uint8Array,
 ) -> Result<Object, String> {
@@ -208,8 +185,8 @@ pub fn rln_witness_to_json(
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen]
-pub fn generate_rln_proof_with_witness(
+#[wasm_bindgen(js_name = generateRLNProofWithWitness)]
+pub fn wasm_generate_rln_proof_with_witness(
     ctx: *mut RLNWrapper,
     calculated_witness: Vec<JsBigInt>,
     serialized_witness: Uint8Array,

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/browser.rs

@@ -0,0 +1,257 @@
+#![cfg(target_arch = "wasm32")]
+
+#[cfg(test)]
+mod tests {
+    use js_sys::{BigInt as JsBigInt, Date, Object, Uint8Array};
+    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
+    use rln::hashers::{hash_to_field, poseidon_hash};
+    use rln::poseidon_tree::PoseidonTree;
+    use rln::protocol::{prepare_verify_input, rln_witness_from_values, serialize_witness};
+    use rln::utils::{bytes_le_to_fr, fr_to_bytes_le};
+    use rln_wasm::{
+        wasm_generate_rln_proof_with_witness, wasm_key_gen, wasm_new, wasm_rln_witness_to_json,
+        wasm_verify_with_roots,
+    };
+    use wasm_bindgen::{prelude::wasm_bindgen, JsValue};
+    use wasm_bindgen_test::{console_log, wasm_bindgen_test, wasm_bindgen_test_configure};
+    use zerokit_utils::merkle_tree::merkle_tree::ZerokitMerkleTree;
+
+    #[cfg(feature = "multithread")]
+    use {rln_wasm::init_thread_pool, wasm_bindgen_futures::JsFuture, web_sys::window};
+
+    #[wasm_bindgen(inline_js = r#"
+    export function isThreadpoolSupported() {
+      return typeof SharedArrayBuffer !== 'undefined' &&
+             typeof Atomics !== 'undefined' &&
+             typeof crossOriginIsolated !== 'undefined' &&
+             crossOriginIsolated;
+    }
+
+    export function initWitnessCalculator(jsCode) {
+      eval(jsCode);
+      if (typeof window.witnessCalculatorBuilder !== 'function') {
+        return false;
+      }
+      return true;
+    }
+
+    export function readFile(data) {
+      return new Uint8Array(data);
+    }
+
+    export async function calculateWitness(circom_data, inputs) {
+      const wasmBuffer = circom_data instanceof Uint8Array ? circom_data : new Uint8Array(circom_data);
+      const witnessCalculator = await window.witnessCalculatorBuilder(wasmBuffer);
+      const calculatedWitness = await witnessCalculator.calculateWitness(inputs, false);
+      return JSON.stringify(calculatedWitness, (key, value) =>
+        typeof value === "bigint" ? value.toString() : value
+      );
+    }
+    "#)]
+    extern "C" {
+        #[wasm_bindgen(catch)]
+        fn isThreadpoolSupported() -> Result<bool, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        fn initWitnessCalculator(js: &str) -> Result<bool, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        fn readFile(data: &[u8]) -> Result<Uint8Array, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        async fn calculateWitness(circom_data: &[u8], inputs: Object) -> Result<JsValue, JsValue>;
+    }
+
+    const WITNESS_CALCULATOR_JS: &str = include_str!("../resources/witness_calculator_browser.js");
+
+    #[cfg(feature = "arkzkey")]
+    const ZKEY_BYTES: &[u8] =
+        include_bytes!("../../rln/resources/tree_height_20/rln_final.arkzkey");
+    #[cfg(not(feature = "arkzkey"))]
+    const ZKEY_BYTES: &[u8] = include_bytes!("../../rln/resources/tree_height_20/rln_final.zkey");
+
+    const CIRCOM_BYTES: &[u8] = include_bytes!("../../rln/resources/tree_height_20/rln.wasm");
+
+    wasm_bindgen_test_configure!(run_in_browser);
+
+    #[wasm_bindgen_test]
+    pub async fn rln_wasm_benchmark() {
+        // Check if thread pool is supported
+        #[cfg(feature = "multithread")]
+        if !isThreadpoolSupported().expect("Failed to check thread pool support") {
+            panic!("Thread pool is NOT supported");
+        } else {
+            // Initialize thread pool
+            let cpu_count = window()
+                .expect("Failed to get window")
+                .navigator()
+                .hardware_concurrency() as usize;
+            JsFuture::from(init_thread_pool(cpu_count))
+                .await
+                .expect("Failed to initialize thread pool");
+        }
+
+        // Initialize the witness calculator
+        initWitnessCalculator(WITNESS_CALCULATOR_JS)
+            .expect("Failed to initialize witness calculator");
+
+        let mut results = String::from("\nbenchmarks:\n");
+        let iterations = 10;
+
+        let zkey = readFile(&ZKEY_BYTES).expect("Failed to read zkey file");
+
+        // Benchmark wasm_new
+        let start_wasm_new = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_new(zkey.clone()).expect("Failed to create RLN instance");
+        }
+        let wasm_new_result = Date::now() - start_wasm_new;
+
+        // Create RLN instance for other benchmarks
+        let rln_instance = wasm_new(zkey).expect("Failed to create RLN instance");
+        let mut tree = PoseidonTree::default(TEST_TREE_HEIGHT).expect("Failed to create tree");
+
+        // Benchmark wasm_key_gen
+        let start_wasm_key_gen = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_key_gen(rln_instance).expect("Failed to generate keys");
+        }
+        let wasm_key_gen_result = Date::now() - start_wasm_key_gen;
+
+        // Generate identity pair for other benchmarks
+        let mem_keys = wasm_key_gen(rln_instance).expect("Failed to generate keys");
+        let id_key = mem_keys.subarray(0, 32);
+        let (identity_secret_hash, _) = bytes_le_to_fr(&id_key.to_vec());
+        let (id_commitment, _) = bytes_le_to_fr(&mem_keys.subarray(32, 64).to_vec());
+
+        let epoch = hash_to_field(b"test-epoch");
+        let rln_identifier = hash_to_field(b"test-rln-identifier");
+        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+
+        let identity_index = tree.leaves_set();
+
+        let user_message_limit = Fr::from(100);
+
+        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+        tree.update_next(rate_commitment)
+            .expect("Failed to update tree");
+
+        let message_id = Fr::from(0);
+        let signal: [u8; 32] = [0; 32];
+        let x = hash_to_field(&signal);
+
+        let merkle_proof = tree
+            .proof(identity_index)
+            .expect("Failed to generate merkle proof");
+
+        let rln_witness = rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x,
+            external_nullifier,
+            user_message_limit,
+            message_id,
+        )
+        .expect("Failed to create RLN witness");
+
+        let serialized_witness =
+            serialize_witness(&rln_witness).expect("Failed to serialize witness");
+        let witness_buffer = Uint8Array::from(&serialized_witness[..]);
+
+        let json_inputs = wasm_rln_witness_to_json(rln_instance, witness_buffer.clone())
+            .expect("Failed to convert witness to JSON");
+
+        // Benchmark calculateWitness
+        let start_calculate_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = calculateWitness(&CIRCOM_BYTES, json_inputs.clone())
+                .await
+                .expect("Failed to calculate witness");
+        }
+        let calculate_witness_result = Date::now() - start_calculate_witness;
+
+        // Calculate witness for other benchmarks
+        let calculated_witness_json = calculateWitness(&CIRCOM_BYTES, json_inputs)
+            .await
+            .expect("Failed to calculate witness")
+            .as_string()
+            .expect("Failed to convert calculated witness to string");
+        let calculated_witness_vec_str: Vec<String> =
+            serde_json::from_str(&calculated_witness_json).expect("Failed to parse JSON");
+        let calculated_witness: Vec<JsBigInt> = calculated_witness_vec_str
+            .iter()
+            .map(|x| JsBigInt::new(&x.into()).expect("Failed to create JsBigInt"))
+            .collect();
+
+        // Benchmark wasm_generate_rln_proof_with_witness
+        let start_wasm_generate_rln_proof_with_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_generate_rln_proof_with_witness(
+                rln_instance,
+                calculated_witness.clone(),
+                witness_buffer.clone(),
+            )
+            .expect("Failed to generate proof");
+        }
+        let wasm_generate_rln_proof_with_witness_result =
+            Date::now() - start_wasm_generate_rln_proof_with_witness;
+
+        // Generate a proof for other benchmarks
+        let proof =
+            wasm_generate_rln_proof_with_witness(rln_instance, calculated_witness, witness_buffer)
+                .expect("Failed to generate proof");
+
+        let proof_data = proof.to_vec();
+        let verify_input = prepare_verify_input(proof_data, &signal);
+        let input_buffer = Uint8Array::from(&verify_input[..]);
+
+        let root = tree.root();
+        let roots_serialized = fr_to_bytes_le(&root);
+        let roots_buffer = Uint8Array::from(&roots_serialized[..]);
+
+        // Benchmark wasm_verify_with_roots
+        let start_wasm_verify_with_roots = Date::now();
+        for _ in 0..iterations {
+            let _ =
+                wasm_verify_with_roots(rln_instance, input_buffer.clone(), roots_buffer.clone())
+                    .expect("Failed to verify proof");
+        }
+        let wasm_verify_with_roots_result = Date::now() - start_wasm_verify_with_roots;
+
+        // Verify the proof with the root
+        let is_proof_valid = wasm_verify_with_roots(rln_instance, input_buffer, roots_buffer)
+            .expect("Failed to verify proof");
+        assert!(is_proof_valid, "verification failed");
+
+        // Format and display results
+        let format_duration = |duration_ms: f64| -> String {
+            let avg_ms = duration_ms / (iterations as f64);
+            if avg_ms >= 1000.0 {
+                format!("{:.3} s", avg_ms / 1000.0)
+            } else {
+                format!("{:.3} ms", avg_ms)
+            }
+        };
+
+        results.push_str(&format!("wasm_new: {}\n", format_duration(wasm_new_result)));
+        results.push_str(&format!(
+            "wasm_key_gen: {}\n",
+            format_duration(wasm_key_gen_result)
+        ));
+        results.push_str(&format!(
+            "calculateWitness: {}\n",
+            format_duration(calculate_witness_result)
+        ));
+        results.push_str(&format!(
+            "wasm_generate_rln_proof_with_witness: {}\n",
+            format_duration(wasm_generate_rln_proof_with_witness_result)
+        ));
+        results.push_str(&format!(
+            "wasm_verify_with_roots: {}\n",
+            format_duration(wasm_verify_with_roots_result)
+        ));
+
+        // Log the results
+        console_log!("{results}");
+    }
+}

rln-wasm/tests/node.rs

@@ -0,0 +1,222 @@
+#![cfg(not(feature = "multithread"))]
+#![cfg(target_arch = "wasm32")]
+
+#[cfg(test)]
+mod tests {
+    use js_sys::{BigInt as JsBigInt, Date, Object, Uint8Array};
+    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
+    use rln::hashers::{hash_to_field, poseidon_hash};
+    use rln::poseidon_tree::PoseidonTree;
+    use rln::protocol::{prepare_verify_input, rln_witness_from_values, serialize_witness};
+    use rln::utils::{bytes_le_to_fr, fr_to_bytes_le};
+    use rln_wasm::{
+        wasm_generate_rln_proof_with_witness, wasm_key_gen, wasm_new, wasm_rln_witness_to_json,
+        wasm_verify_with_roots,
+    };
+    use wasm_bindgen::{prelude::wasm_bindgen, JsValue};
+    use wasm_bindgen_test::{console_log, wasm_bindgen_test};
+    use zerokit_utils::merkle_tree::merkle_tree::ZerokitMerkleTree;
+
+    #[wasm_bindgen(inline_js = r#"
+    const fs = require("fs");
+
+    module.exports = {
+      readFile: function (path) {
+        return fs.readFileSync(path);
+      },
+
+      calculateWitness: async function (circom_path, inputs) {
+        const wc = require("resources/witness_calculator_node.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
+        );
+      },
+    };
+    "#)]
+    extern "C" {
+        #[wasm_bindgen(catch)]
+        fn readFile(path: &str) -> Result<Uint8Array, JsValue>;
+
+        #[wasm_bindgen(catch)]
+        async fn calculateWitness(circom_path: &str, input: Object) -> Result<JsValue, JsValue>;
+    }
+
+    #[cfg(feature = "arkzkey")]
+    const ZKEY_PATH: &str = "../rln/resources/tree_height_20/rln_final.arkzkey";
+    #[cfg(not(feature = "arkzkey"))]
+    const ZKEY_PATH: &str = "../rln/resources/tree_height_20/rln_final.zkey";
+
+    const CIRCOM_PATH: &str = "../rln/resources/tree_height_20/rln.wasm";
+
+    #[wasm_bindgen_test]
+    pub async fn rln_wasm_benchmark() {
+        let mut results = String::from("\nbenchmarks:\n");
+        let iterations = 10;
+
+        let zkey = readFile(&ZKEY_PATH).expect("Failed to read zkey file");
+
+        // Benchmark wasm_new
+        let start_wasm_new = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_new(zkey.clone()).expect("Failed to create RLN instance");
+        }
+        let wasm_new_result = Date::now() - start_wasm_new;
+
+        // Create RLN instance for other benchmarks
+        let rln_instance = wasm_new(zkey).expect("Failed to create RLN instance");
+        let mut tree = PoseidonTree::default(TEST_TREE_HEIGHT).expect("Failed to create tree");
+
+        // Benchmark wasm_key_gen
+        let start_wasm_key_gen = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_key_gen(rln_instance).expect("Failed to generate keys");
+        }
+        let wasm_key_gen_result = Date::now() - start_wasm_key_gen;
+
+        // Generate identity pair for other benchmarks
+        let mem_keys = wasm_key_gen(rln_instance).expect("Failed to generate keys");
+        let id_key = mem_keys.subarray(0, 32);
+        let (identity_secret_hash, _) = bytes_le_to_fr(&id_key.to_vec());
+        let (id_commitment, _) = bytes_le_to_fr(&mem_keys.subarray(32, 64).to_vec());
+
+        let epoch = hash_to_field(b"test-epoch");
+        let rln_identifier = hash_to_field(b"test-rln-identifier");
+        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+
+        let identity_index = tree.leaves_set();
+
+        let user_message_limit = Fr::from(100);
+
+        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+        tree.update_next(rate_commitment)
+            .expect("Failed to update tree");
+
+        let message_id = Fr::from(0);
+        let signal: [u8; 32] = [0; 32];
+        let x = hash_to_field(&signal);
+
+        let merkle_proof = tree
+            .proof(identity_index)
+            .expect("Failed to generate merkle proof");
+
+        let rln_witness = rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x,
+            external_nullifier,
+            user_message_limit,
+            message_id,
+        )
+        .expect("Failed to create RLN witness");
+
+        let serialized_witness =
+            serialize_witness(&rln_witness).expect("Failed to serialize witness");
+        let witness_buffer = Uint8Array::from(&serialized_witness[..]);
+
+        let json_inputs = wasm_rln_witness_to_json(rln_instance, witness_buffer.clone())
+            .expect("Failed to convert witness to JSON");
+
+        // Benchmark calculateWitness
+        let start_calculate_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = calculateWitness(&CIRCOM_PATH, json_inputs.clone())
+                .await
+                .expect("Failed to calculate witness");
+        }
+        let calculate_witness_result = Date::now() - start_calculate_witness;
+
+        // Calculate witness for other benchmarks
+        let calculated_witness_json = calculateWitness(&CIRCOM_PATH, json_inputs)
+            .await
+            .expect("Failed to calculate witness")
+            .as_string()
+            .expect("Failed to convert calculated witness to string");
+        let calculated_witness_vec_str: Vec<String> =
+            serde_json::from_str(&calculated_witness_json).expect("Failed to parse JSON");
+        let calculated_witness: Vec<JsBigInt> = calculated_witness_vec_str
+            .iter()
+            .map(|x| JsBigInt::new(&x.into()).expect("Failed to create JsBigInt"))
+            .collect();
+
+        // Benchmark wasm_generate_rln_proof_with_witness
+        let start_wasm_generate_rln_proof_with_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_generate_rln_proof_with_witness(
+                rln_instance,
+                calculated_witness.clone(),
+                witness_buffer.clone(),
+            )
+            .expect("Failed to generate proof");
+        }
+        let wasm_generate_rln_proof_with_witness_result =
+            Date::now() - start_wasm_generate_rln_proof_with_witness;
+
+        // Generate a proof for other benchmarks
+        let proof =
+            wasm_generate_rln_proof_with_witness(rln_instance, calculated_witness, witness_buffer)
+                .expect("Failed to generate proof");
+
+        let proof_data = proof.to_vec();
+        let verify_input = prepare_verify_input(proof_data, &signal);
+        let input_buffer = Uint8Array::from(&verify_input[..]);
+
+        let root = tree.root();
+        let roots_serialized = fr_to_bytes_le(&root);
+        let roots_buffer = Uint8Array::from(&roots_serialized[..]);
+
+        // Benchmark wasm_verify_with_roots
+        let start_wasm_verify_with_roots = Date::now();
+        for _ in 0..iterations {
+            let _ =
+                wasm_verify_with_roots(rln_instance, input_buffer.clone(), roots_buffer.clone())
+                    .expect("Failed to verify proof");
+        }
+        let wasm_verify_with_roots_result = Date::now() - start_wasm_verify_with_roots;
+
+        // Verify the proof with the root
+        let is_proof_valid = wasm_verify_with_roots(rln_instance, input_buffer, roots_buffer)
+            .expect("Failed to verify proof");
+        assert!(is_proof_valid, "verification failed");
+
+        // Format and display results
+        let format_duration = |duration_ms: f64| -> String {
+            let avg_ms = duration_ms / (iterations as f64);
+            if avg_ms >= 1000.0 {
+                format!("{:.3} s", avg_ms / 1000.0)
+            } else {
+                format!("{:.3} ms", avg_ms)
+            }
+        };
+
+        results.push_str(&format!("wasm_new: {}\n", format_duration(wasm_new_result)));
+        results.push_str(&format!(
+            "wasm_key_gen: {}\n",
+            format_duration(wasm_key_gen_result)
+        ));
+        results.push_str(&format!(
+            "calculate_witness: {}\n",
+            format_duration(calculate_witness_result)
+        ));
+        results.push_str(&format!(
+            "wasm_generate_rln_proof_with_witness: {}\n",
+            format_duration(wasm_generate_rln_proof_with_witness_result)
+        ));
+        results.push_str(&format!(
+            "wasm_verify_with_roots: {}\n",
+            format_duration(wasm_verify_with_roots_result)
+        ));
+
+        // Log the results
+        console_log!("{results}");
+    }
+}

rln-wasm/tests/rln-wasm.rs

@@ -1,123 +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 rln::poseidon_tree::PoseidonTree;
-    use rln::utils::vec_fr_to_bytes_le;
-    use wasm_bindgen::{prelude::*, JsValue};
-    use wasm_bindgen_test::wasm_bindgen_test;
-    use zerokit_utils::merkle_tree::merkle_tree::ZerokitMerkleTree;
-    use zerokit_utils::ZerokitMerkleProof;
-     use rln::utils::vec_u8_to_bytes_le;
-
-    #[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.arkvkey");
-        let zkey = read_file(&zkey_path).unwrap();
-        let vk = read_file(&vk_path).unwrap();
-
-        // Creating an instance of RLN
-        let rln_instance = wasm_new(zkey, vk).unwrap();
-
-        let mut tree = PoseidonTree::default(TEST_TREE_HEIGHT).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 = tree.leaves_set();
-        // 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]);
-        tree.update_next(rate_commitment).unwrap();
-
-        let x = hash_to_field(signal);
-        let merkle_proof = tree.proof(identity_index).expect("proof should exist");
-        let path_elements = merkle_proof.get_path_elements();
-        let identity_path_index = merkle_proof.get_path_index();
-
-
-        // Serializing the message
-        let mut serialized_vec: Vec<u8> = Vec::new();
-        serialized_vec.append(&mut id_key.to_vec());
-        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 vec_fr_to_bytes_le(&path_elements).unwrap());
-        serialized_vec.append(&mut vec_u8_to_bytes_le(&identity_path_index).unwrap());
-        serialized_vec.append(&mut fr_to_bytes_le(&x));
-        serialized_vec.append(&mut external_nullifier.to_vec());
-        let serialized_message = Uint8Array::from(&serialized_vec[..]);
-
-        // Obtaining inputs that should be sent to circom witness calculator
-        let json_inputs =
-            rln_witness_to_json(rln_instance, serialized_message.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_message,
-        )
-        .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[..]);
-
-        // Validating Proof with Roots
-        let root = tree.root();
-        let root_le = fr_to_bytes_le(&root);
-        let roots = Uint8Array::from(&root_le[..]);
-        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");
-    }
-}

rln/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rln"
-version = "0.5.1"
+version = "0.8.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
@@ -9,94 +9,82 @@ homepage = "https://vac.dev"
 repository = "https://github.com/vacp2p/zerokit"
 
 [lib]
-crate-type = ["rlib", "staticlib"]
+crate-type = ["rlib", "staticlib", "cdylib"]
 bench = false
 
 # This flag disable cargo doctests, i.e. testing example code-snippets in documentation
 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-relations = { version = "0.5.1", features = ["std"] }
+ark-ff = { version = "0.5.0", default-features = false, features = [
     "parallel",
-], default-features = false }
-ark-relations = { version = "=0.4.0", 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-ec = { version = "0.5.0", default-features = false, features = [
+    "parallel",
 ] }
-ark-zkey = { version = "0.1.0", optional = true, default-features = false }
 
-# WASM
-wasmer = { version = "=2.3.0", default-features = false }
+ark-std = { version = "0.5.0", default-features = false, features = [
+    "parallel",
+] }
+ark-poly = { version = "0.5.0", default-features = false, features = [
+    "parallel",
+] }
+ark-groth16 = { version = "0.5.0", default-features = false, features = [
+    "parallel",
+] }
+ark-serialize = { version = "0.5.0", default-features = false, features = [
+    "parallel",
+] }
 
 # error handling
-color-eyre = "=0.6.2"
-thiserror = "=1.0.39"
+thiserror = "2.0.12"
 
 # utilities
-cfg-if = "=1.0"
-num-bigint = { version = "=0.4.3", default-features = false, features = [
-    "rand",
-] }
-num-traits = "=0.2.15"
-once_cell = "=1.17.1"
-lazy_static = "=1.4.0"
-rand = "=0.8.5"
-rand_chacha = "=0.3.1"
-tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
-utils = { package = "zerokit_utils", version = "=0.5.1", path = "../utils/", default-features = false }
-
+byteorder = "1.5.0"
+cfg-if = "1.0"
+num-bigint = { version = "0.4.6", default-features = false, features = ["std"] }
+num-traits = "0.2.19"
+once_cell = "1.21.3"
+lazy_static = "1.5.0"
+rand = "0.8.5"
+rand_chacha = "0.3.1"
+ruint = { version = "1.15.0", features = ["rand", "serde", "ark-ff-04"] }
+tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+utils = { package = "zerokit_utils", version = "0.6.0", path = "../utils", default-features = false }
 
 # serialization
-serde_json = "=1.0.96"
-serde = { version = "=1.0.163", features = ["derive"] }
+prost = "0.13.5"
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
 
-document-features = { version = "=0.2.10", optional = true }
+document-features = { version = "0.2.11", optional = true }
 
 [dev-dependencies]
-sled = "=0.34.7"
-criterion = { version = "=0.4.0", features = ["html_reports"] }
+criterion = { version = "0.6.0", features = ["html_reports"] }
 
 [features]
-default = ["parallel", "wasmer/sys-default", "pmtree-ft"]
-parallel = [
-    "ark-ec/parallel",
-    "ark-ff/parallel",
-    "ark-std/parallel",
-    "ark-groth16/parallel",
-    "utils/parallel",
-]
-wasm = ["wasmer/js", "wasmer/std"]
-fullmerkletree = ["default"]
-arkzkey = ["ark-zkey"]
+default = ["pmtree-ft"]
+fullmerkletree = []
 stateless = []
+arkzkey = []
 
 # Note: pmtree feature is still experimental
 pmtree-ft = ["utils/pmtree-ft"]
 
-[[bench]]
-name = "pmtree_benchmark"
-harness = false
-
-[[bench]]
-name = "circuit_loading_benchmark"
-harness = false
-
 [[bench]]
 name = "circuit_loading_arkzkey_benchmark"
 harness = false
 required-features = ["arkzkey"]
 
 [[bench]]
-name = "circuit_deser_benchmark"
+name = "circuit_loading_benchmark"
+harness = false
+
+[[bench]]
+name = "pmtree_benchmark"
 harness = false
 
 [[bench]]

rln/Makefile.toml

@@ -2,9 +2,9 @@
 command = "cargo"
 args = ["build", "--release"]
 
-[tasks.test_default]
+[tasks.test]
 command = "cargo"
-args = ["test", "--release"]
+args = ["test", "--release", "--", "--nocapture"]
 
 [tasks.test_stateless]
 command = "cargo"

rln/README.md

@@ -1,65 +1,22 @@
 # Zerokit RLN Module
 
-This module provides APIs to manage, compute and verify [RLN](https://rfc.vac.dev/spec/32/) zkSNARK proofs and RLN primitives.
+[![Crates.io](https://img.shields.io/crates/v/rln.svg)](https://crates.io/crates/rln)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 
-## 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 0.7.0 is the only version that does not support WASM and x32 architecture.
+> WASM support is available in version 0.8.0 and above.
 
 ### Add RLN as dependency
 
@@ -70,136 +27,271 @@ 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.
+The RLN object constructor requires the following files:
 
-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.arkvkey`, optional) are found.
+- `graph.bin`: The graph file built for the input tree size
+- `rln_final.zkey` or `rln_final_uncompr.arkzkey`: The proving key
+- `verification_key.arkvkey`: The verification key (optional)
 
-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.
+Additionally, `rln.wasm` is used for testing in the rln-wasm module.
+
+In the following we will use [cursors](https://doc.rust-lang.org/std/io/struct.Cursor.html)
+as readers/writers for interfacing with RLN public APIs.
 
 ```rust
-use 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_prove_input, prepare_verify_input},
+    public::RLN,
+    utils::fr_to_bytes_le,
+};
+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 = Fr::from(10);
+    let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+    let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
+    rln.set_leaf(id_index, &mut buffer).unwrap();
+
+    // 4. Set up external nullifier (epoch + app identifier)
+    // We generate epoch from a date seed and we ensure is
+    // mapped to a field element by hashing-to-field its content
+    let epoch = hash_to_field(b"Today at noon, this year");
+    // We generate rln_identifier from a date seed and we ensure is
+    // mapped to a field element by hashing-to-field its content
+    let rln_identifier = hash_to_field(b"test-rln-identifier");
+    // We generate a external nullifier
+    let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+    // We choose a message_id satisfy 0 <= message_id < user_message_limit
+    let message_id = Fr::from(1);
+
+    // 5. Generate and verify a proof for a message
+    let signal = b"RLN is awesome";
+
+    // 6. Prepare input for generate_rln_proof API
+    // input_data is [ identity_secret<32> | id_index<8> | external_nullifier<32> 
+    //    | user_message_limit<32> | message_id<32> | signal_len<8> | signal<var> ]
+    let prove_input = prepare_prove_input(
+        identity_secret_hash,
+        id_index,
+        user_message_limit,
+        message_id,
+        external_nullifier,
+        signal,
+    );
+
+    // 7. Generate a RLN proof
+    // We generate a RLN proof for proof_input
+    let mut input_buffer = Cursor::new(prove_input);
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
+        .unwrap();
+
+    // We get the public outputs returned by the circuit evaluation
+    // The byte vector `proof_data` is serialized as 
+    //  `[ zk-proof | tree_root | external_nullifier | share_x | share_y | nullifier ]`.
+    let proof_data = output_buffer.into_inner();
+
+    // 8. Verify a RLN proof
+    // Input buffer is serialized as `[proof_data | signal_len | signal ]`,
+    //   where `proof_data` is (computed as) the output obtained by `generate_rln_proof`.
+    let verify_data = prepare_verify_input(proof_data, signal);
+
+    // We verify the zk-proof against the provided proof values
+    let mut input_buffer = Cursor::new(verify_data);
+    let verified = rln.verify_rln_proof(&mut input_buffer).unwrap();
+
+    // We ensure the proof is valid
+    assert!(verified);
+}
 ```
 
-### 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.
+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 depth of 20
+- **Wasm Support**: WebAssembly bindings via rln-wasm crate with features like:
+  - Browser and Node.js compatibility
+  - Optional multi-threading support using wasm-bindgen-rayon
+  - Headless browser testing capabilities
+
+## 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 depth, 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 depth `20` and a bit size of `16`,
+> allowing up to `2^20` registered members and a `2^16` message limit per epoch.
+
+#### Install circom compiler
+
+You can follow the instructions below or refer to the
+[installing Circom](https://docs.circom.io/getting-started/installation/#installing-circom) guide for more details,
+but make sure to use the specific version `v2.1.0`.
+
+```sh
+# Clone the circom repository
+git clone https://github.com/iden3/circom.git
+
+# Checkout the specific version
+cd circom && git checkout v2.1.0
+
+# Build the circom compiler
+cargo build --release
+
+# Install the circom binary globally
+cargo install --path circom
+
+# Check the circom version to ensure it's v2.1.0
+circom --version
 ```
 
-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 +302,20 @@ 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_deser_benchmark.rs

@@ -1,22 +0,0 @@
-use criterion::{criterion_group, criterion_main, Criterion};
-use rln::circuit::{vk_from_ark_serialized, VK_BYTES};
-
-// Here we benchmark how long the deserialization of the
-// verifying_key takes, only testing the json => verifying_key conversion,
-// and skipping conversion from bytes => string => serde_json::Value
-pub fn vk_deserialize_benchmark(c: &mut Criterion) {
-    let vk = VK_BYTES;
-
-    c.bench_function("vk::vk_from_ark_serialized", |b| {
-        b.iter(|| {
-            let _ = vk_from_ark_serialized(vk);
-        })
-    });
-}
-
-criterion_group! {
-    name = benches;
-    config = Criterion::default().measurement_time(std::time::Duration::from_secs(10));
-    targets = vk_deserialize_benchmark
-}
-criterion_main!(benches);

rln/benches/circuit_loading_arkzkey_benchmark.rs

@@ -1,11 +1,8 @@
 use criterion::{criterion_group, criterion_main, Criterion};
-use rln::circuit::{
-    read_arkzkey_from_bytes_compressed, read_arkzkey_from_bytes_uncompressed, ARKZKEY_BYTES,
-    ARKZKEY_BYTES_UNCOMPR,
-};
+use rln::circuit::{read_arkzkey_from_bytes_uncompressed, ARKZKEY_BYTES};
 
 pub fn uncompressed_bench(c: &mut Criterion) {
-    let arkzkey = ARKZKEY_BYTES_UNCOMPR.to_vec();
+    let arkzkey = ARKZKEY_BYTES.to_vec();
     let size = arkzkey.len() as f32;
     println!(
         "Size of uncompressed arkzkey: {:.2?} MB",
@@ -19,25 +16,10 @@ pub fn uncompressed_bench(c: &mut Criterion) {
         })
     });
 }
-pub fn compressed_bench(c: &mut Criterion) {
-    let arkzkey = ARKZKEY_BYTES.to_vec();
-    let size = arkzkey.len() as f32;
-    println!(
-        "Size of compressed arkzkey: {:.2?} MB",
-        size / 1024.0 / 1024.0
-    );
-
-    c.bench_function("arkzkey::arkzkey_from_raw_compressed", |b| {
-        b.iter(|| {
-            let r = read_arkzkey_from_bytes_compressed(&arkzkey);
-            assert_eq!(r.is_ok(), true);
-        })
-    });
-}
 
 criterion_group! {
     name = benches;
-    config = Criterion::default().measurement_time(std::time::Duration::from_secs(250));
-    targets = uncompressed_bench, compressed_bench
+    config = Criterion::default().sample_size(10);
+    targets = uncompressed_bench
 }
 criterion_main!(benches);

rln/benches/circuit_loading_benchmark.rs

@@ -1,5 +1,5 @@
-use ark_circom::read_zkey;
 use criterion::{criterion_group, criterion_main, Criterion};
+use rln::circuit::zkey::read_zkey;
 use std::io::Cursor;
 
 pub fn zkey_load_benchmark(c: &mut Criterion) {
@@ -18,7 +18,7 @@ pub fn zkey_load_benchmark(c: &mut Criterion) {
 
 criterion_group! {
     name = benches;
-    config = Criterion::default().measurement_time(std::time::Duration::from_secs(250));
+    config = Criterion::default().sample_size(10);
     targets = zkey_load_benchmark
 }
 criterion_main!(benches);

rln/benches/pmtree_benchmark.rs

@@ -21,17 +21,11 @@ pub fn pmtree_benchmark(c: &mut Criterion) {
 
     c.bench_function("Pmtree::override_range", |b| {
         b.iter(|| {
-            tree.override_range(0, leaves.clone(), [0, 1, 2, 3])
+            tree.override_range(0, leaves.clone().into_iter(), [0, 1, 2, 3].into_iter())
                 .unwrap();
         })
     });
 
-    c.bench_function("Pmtree::compute_root", |b| {
-        b.iter(|| {
-            tree.compute_root().unwrap();
-        })
-    });
-
     c.bench_function("Pmtree::get", |b| {
         b.iter(|| {
             tree.get(0).unwrap();

rln/src/circuit.rs

@@ -1,225 +0,0 @@
-// This crate provides interfaces for the zero-knowledge circuit and keys
-
-use ark_bn254::{
-    Bn254, Fq as ArkFq, Fq2 as ArkFq2, Fr as ArkFr, G1Affine as ArkG1Affine,
-    G1Projective as ArkG1Projective, G2Affine as ArkG2Affine, G2Projective as ArkG2Projective,
-};
-use ark_groth16::{ProvingKey, VerifyingKey};
-use ark_relations::r1cs::ConstraintMatrices;
-use ark_serialize::CanonicalDeserialize;
-use cfg_if::cfg_if;
-use color_eyre::{Report, Result};
-
-#[cfg(not(target_arch = "wasm32"))]
-use {
-    ark_circom::WitnessCalculator,
-    lazy_static::lazy_static,
-    std::sync::{Arc, Mutex},
-    wasmer::{Module, Store},
-};
-
-#[cfg(feature = "arkzkey")]
-use {
-    ark_zkey::{read_arkzkey_from_bytes, SerializableConstraintMatrices, SerializableProvingKey},
-    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");
-#[cfg(feature = "arkzkey")]
-pub const ARKZKEY_BYTES_UNCOMPR: &[u8] =
-    include_bytes!("../resources/tree_height_20/rln_final_uncompr.arkzkey");
-
-pub const ZKEY_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/rln_final.zkey");
-pub const VK_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/verification_key.arkvkey");
-const WASM_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/rln.wasm");
-
-#[cfg(not(target_arch = "wasm32"))]
-lazy_static! {
-    #[cfg(not(target_arch = "wasm32"))]
-    static ref ZKEY: (ProvingKey<Curve>, ConstraintMatrices<Fr>) = {
-        cfg_if! {
-                if #[cfg(feature = "arkzkey")] {
-                    read_arkzkey_from_bytes_uncompressed(ARKZKEY_BYTES_UNCOMPR).expect("Failed to read arkzkey")
-                } else {
-                    let mut reader = Cursor::new(ZKEY_BYTES);
-                    read_zkey(&mut reader).expect("Failed to read zkey")
-                }
-        }
-    };
-
-    #[cfg(not(target_arch = "wasm32"))]
-    static ref VK: VerifyingKey<Curve> = vk_from_ark_serialized(VK_BYTES).expect("Failed to read vk");
-
-    #[cfg(not(target_arch = "wasm32"))]
-    static ref WITNESS_CALCULATOR: Arc<Mutex<WitnessCalculator>> = {
-        circom_from_raw(WASM_BYTES).expect("Failed to create witness calculator")
-    };
-}
-
-pub const TEST_TREE_HEIGHT: usize = 20;
-
-// The following types define the pairing friendly elliptic curve, the underlying finite fields and groups default to this module
-// Note that proofs are serialized assuming Fr to be 4x8 = 32 bytes in size. Hence, changing to a curve with different encoding will make proof verification to fail
-pub type Curve = Bn254;
-pub type Fr = ArkFr;
-pub type Fq = ArkFq;
-pub type Fq2 = ArkFq2;
-pub type G1Affine = ArkG1Affine;
-pub type G1Projective = ArkG1Projective;
-pub type G2Affine = ArkG2Affine;
-pub type G2Projective = ArkG2Projective;
-
-// Loads the proving key using a bytes vector
-pub fn zkey_from_raw(zkey_data: &[u8]) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
-    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(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() -> &'static (ProvingKey<Curve>, ConstraintMatrices<Fr>) {
-    &ZKEY
-}
-
-// Loads the verification key from a bytes vector
-pub fn vk_from_raw(vk_data: &[u8], zkey_data: &[u8]) -> Result<VerifyingKey<Curve>> {
-    if !vk_data.is_empty() {
-        return vk_from_ark_serialized(vk_data);
-    }
-
-    if !zkey_data.is_empty() {
-        let (proving_key, _matrices) = zkey_from_raw(zkey_data)?;
-        return Ok(proving_key.vk);
-    }
-
-    Err(Report::msg("No proving/verification key found!"))
-}
-
-// Loads the verification key
-#[cfg(not(target_arch = "wasm32"))]
-pub fn vk_from_folder() -> &'static VerifyingKey<Curve> {
-    &VK
-}
-
-// Initializes the witness calculator using a bytes vector
-#[cfg(not(target_arch = "wasm32"))]
-pub fn circom_from_raw(wasm_buffer: &[u8]) -> Result<Arc<Mutex<WitnessCalculator>>> {
-    let module = Module::new(&Store::default(), wasm_buffer)?;
-    let result = WitnessCalculator::from_module(module)?;
-    Ok(Arc::new(Mutex::new(result)))
-}
-
-// Initializes the witness calculator
-#[cfg(not(target_arch = "wasm32"))]
-pub fn circom_from_folder() -> &'static Arc<Mutex<WitnessCalculator>> {
-    &WITNESS_CALCULATOR
-}
-
-// Computes the verification key from a bytes vector containing pre-processed ark-serialized verification key
-// uncompressed, unchecked
-pub fn vk_from_ark_serialized(data: &[u8]) -> Result<VerifyingKey<Curve>> {
-    let vk = VerifyingKey::<Curve>::deserialize_uncompressed_unchecked(data)?;
-    Ok(vk)
-}
-
-// 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();
-    if proving_key.vk == verifying_key {
-        Ok(())
-    } else {
-        Err(Report::msg("verifying_keys are not equal"))
-    }
-}
-
-////////////////////////////////////////////////////////
-// Functions 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")]
-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))
-}
-
-#[cfg(feature = "arkzkey")]
-pub fn read_arkzkey_from_bytes_compressed(
-    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_compressed_unchecked(&mut cursor)
-            .wrap_err("Failed to deserialize proving key")?;
-
-    let serialized_constraint_matrices =
-        SerializableConstraintMatrices::deserialize_compressed_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/circuit/error.rs

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

rln/src/circuit/iden3calc.rs

@@ -0,0 +1,73 @@
+// 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/circuit/iden3calc/graph.rs

@@ -0,0 +1,957 @@
+// This file is based on the code by iden3. Its preimage can be found here:
+// https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/src/graph.rs
+
+use ark_ff::{BigInt, BigInteger, One, PrimeField, Zero};
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize, Compress, Validate};
+use rand::Rng;
+use ruint::{aliases::U256, uint};
+use serde::{Deserialize, Serialize};
+use std::{
+    cmp::Ordering,
+    collections::HashMap,
+    error::Error,
+    ops::{Deref, Shl, Shr},
+};
+
+use crate::circuit::iden3calc::proto;
+use crate::circuit::Fr;
+
+pub const M: U256 =
+    uint!(21888242871839275222246405745257275088548364400416034343698204186575808495617_U256);
+
+fn ark_se<S, A: CanonicalSerialize>(a: &A, s: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    let mut bytes = vec![];
+    a.serialize_with_mode(&mut bytes, Compress::Yes)
+        .map_err(serde::ser::Error::custom)?;
+    s.serialize_bytes(&bytes)
+}
+
+fn ark_de<'de, D, A: CanonicalDeserialize>(data: D) -> Result<A, D::Error>
+where
+    D: serde::de::Deserializer<'de>,
+{
+    let s: Vec<u8> = serde::de::Deserialize::deserialize(data)?;
+    let a = A::deserialize_with_mode(s.as_slice(), Compress::Yes, Validate::Yes);
+    a.map_err(serde::de::Error::custom)
+}
+
+#[inline(always)]
+pub fn fr_to_u256(x: &Fr) -> U256 {
+    U256::from_limbs(x.into_bigint().0)
+}
+
+#[inline(always)]
+pub fn u256_to_fr(x: &U256) -> Fr {
+    Fr::from_bigint(BigInt::new(x.into_limbs())).expect("Failed to convert U256 to Fr")
+}
+
+#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
+pub enum Operation {
+    Mul,
+    Div,
+    Add,
+    Sub,
+    Pow,
+    Idiv,
+    Mod,
+    Eq,
+    Neq,
+    Lt,
+    Gt,
+    Leq,
+    Geq,
+    Land,
+    Lor,
+    Shl,
+    Shr,
+    Bor,
+    Band,
+    Bxor,
+}
+
+impl Operation {
+    // TODO: rewrite to &U256 type
+    pub fn eval(&self, a: U256, b: U256) -> U256 {
+        use Operation::*;
+        match self {
+            Mul => a.mul_mod(b, M),
+            Div => {
+                if b == U256::ZERO {
+                    // as we are simulating a circuit execution with signals
+                    // values all equal to 0, just return 0 here in case of
+                    // division by zero
+                    U256::ZERO
+                } else {
+                    a.mul_mod(b.inv_mod(M).unwrap(), M)
+                }
+            }
+            Add => a.add_mod(b, M),
+            Sub => a.add_mod(M - b, M),
+            Pow => a.pow_mod(b, M),
+            Mod => a.div_rem(b).1,
+            Eq => U256::from(a == b),
+            Neq => U256::from(a != b),
+            Lt => u_lt(&a, &b),
+            Gt => u_gt(&a, &b),
+            Leq => u_lte(&a, &b),
+            Geq => u_gte(&a, &b),
+            Land => U256::from(a != U256::ZERO && b != U256::ZERO),
+            Lor => U256::from(a != U256::ZERO || b != U256::ZERO),
+            Shl => compute_shl_uint(a, b),
+            Shr => compute_shr_uint(a, b),
+            // TODO test with conner case when it is possible to get the number
+            //      bigger then modulus
+            Bor => a.bitor(b),
+            Band => a.bitand(b),
+            // TODO test with conner case when it is possible to get the number
+            //      bigger then modulus
+            Bxor => a.bitxor(b),
+            Idiv => a / b,
+        }
+    }
+
+    pub fn eval_fr(&self, a: Fr, b: Fr) -> Fr {
+        use Operation::*;
+        match self {
+            Mul => a * b,
+            // We always should return something on the circuit execution.
+            // So in case of division by 0 we would return 0. And the proof
+            // should be invalid in the end.
+            Div => {
+                if b.is_zero() {
+                    Fr::zero()
+                } else {
+                    a / b
+                }
+            }
+            Add => a + b,
+            Sub => a - b,
+            Idiv => {
+                if b.is_zero() {
+                    Fr::zero()
+                } else {
+                    let a_u256 = fr_to_u256(&a);
+                    let b_u256 = fr_to_u256(&b);
+                    u256_to_fr(&(a_u256 / b_u256))
+                }
+            }
+            Mod => {
+                if b.is_zero() {
+                    Fr::zero()
+                } else {
+                    let a_u256 = fr_to_u256(&a);
+                    let b_u256 = fr_to_u256(&b);
+                    u256_to_fr(&(a_u256 % b_u256))
+                }
+            }
+            Eq => match a.cmp(&b) {
+                Ordering::Equal => Fr::one(),
+                _ => Fr::zero(),
+            },
+            Neq => match a.cmp(&b) {
+                Ordering::Equal => Fr::zero(),
+                _ => Fr::one(),
+            },
+            Lt => u256_to_fr(&u_lt(&fr_to_u256(&a), &fr_to_u256(&b))),
+            Gt => u256_to_fr(&u_gt(&fr_to_u256(&a), &fr_to_u256(&b))),
+            Leq => u256_to_fr(&u_lte(&fr_to_u256(&a), &fr_to_u256(&b))),
+            Geq => u256_to_fr(&u_gte(&fr_to_u256(&a), &fr_to_u256(&b))),
+            Land => {
+                if a.is_zero() || b.is_zero() {
+                    Fr::zero()
+                } else {
+                    Fr::one()
+                }
+            }
+            Lor => {
+                if a.is_zero() && b.is_zero() {
+                    Fr::zero()
+                } else {
+                    Fr::one()
+                }
+            }
+            Shl => shl(a, b),
+            Shr => shr(a, b),
+            Bor => bit_or(a, b),
+            Band => bit_and(a, b),
+            Bxor => bit_xor(a, b),
+            // TODO implement other operators
+            _ => unimplemented!("operator {:?} not implemented for Montgomery", self),
+        }
+    }
+}
+
+impl From<&Operation> for proto::DuoOp {
+    fn from(v: &Operation) -> Self {
+        match v {
+            Operation::Mul => proto::DuoOp::Mul,
+            Operation::Div => proto::DuoOp::Div,
+            Operation::Add => proto::DuoOp::Add,
+            Operation::Sub => proto::DuoOp::Sub,
+            Operation::Pow => proto::DuoOp::Pow,
+            Operation::Idiv => proto::DuoOp::Idiv,
+            Operation::Mod => proto::DuoOp::Mod,
+            Operation::Eq => proto::DuoOp::Eq,
+            Operation::Neq => proto::DuoOp::Neq,
+            Operation::Lt => proto::DuoOp::Lt,
+            Operation::Gt => proto::DuoOp::Gt,
+            Operation::Leq => proto::DuoOp::Leq,
+            Operation::Geq => proto::DuoOp::Geq,
+            Operation::Land => proto::DuoOp::Land,
+            Operation::Lor => proto::DuoOp::Lor,
+            Operation::Shl => proto::DuoOp::Shl,
+            Operation::Shr => proto::DuoOp::Shr,
+            Operation::Bor => proto::DuoOp::Bor,
+            Operation::Band => proto::DuoOp::Band,
+            Operation::Bxor => proto::DuoOp::Bxor,
+        }
+    }
+}
+
+#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
+pub enum UnoOperation {
+    Neg,
+    Id, // identity - just return self
+}
+
+impl UnoOperation {
+    pub fn eval(&self, a: U256) -> U256 {
+        match self {
+            UnoOperation::Neg => {
+                if a == U256::ZERO {
+                    U256::ZERO
+                } else {
+                    M - a
+                }
+            }
+            UnoOperation::Id => a,
+        }
+    }
+
+    pub fn eval_fr(&self, a: Fr) -> Fr {
+        match self {
+            UnoOperation::Neg => {
+                if a.is_zero() {
+                    Fr::zero()
+                } else {
+                    let mut x = Fr::MODULUS;
+                    x.sub_with_borrow(&a.into_bigint());
+                    Fr::from_bigint(x).unwrap()
+                }
+            }
+            _ => unimplemented!("uno operator {:?} not implemented for Montgomery", self),
+        }
+    }
+}
+
+impl From<&UnoOperation> for proto::UnoOp {
+    fn from(v: &UnoOperation) -> Self {
+        match v {
+            UnoOperation::Neg => proto::UnoOp::Neg,
+            UnoOperation::Id => proto::UnoOp::Id,
+        }
+    }
+}
+
+#[derive(Hash, PartialEq, Eq, Debug, Clone, Copy, Serialize, Deserialize)]
+pub enum TresOperation {
+    TernCond,
+}
+
+impl TresOperation {
+    pub fn eval(&self, a: U256, b: U256, c: U256) -> U256 {
+        match self {
+            TresOperation::TernCond => {
+                if a == U256::ZERO {
+                    c
+                } else {
+                    b
+                }
+            }
+        }
+    }
+
+    pub fn eval_fr(&self, a: Fr, b: Fr, c: Fr) -> Fr {
+        match self {
+            TresOperation::TernCond => {
+                if a.is_zero() {
+                    c
+                } else {
+                    b
+                }
+            }
+        }
+    }
+}
+
+impl From<&TresOperation> for proto::TresOp {
+    fn from(v: &TresOperation) -> Self {
+        match v {
+            TresOperation::TernCond => proto::TresOp::TernCond,
+        }
+    }
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+pub enum Node {
+    Input(usize),
+    Constant(U256),
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
+    MontConstant(Fr),
+    UnoOp(UnoOperation, usize),
+    Op(Operation, usize, usize),
+    TresOp(TresOperation, usize, usize, usize),
+}
+
+// TODO remove pub from Vec<Node>
+#[derive(Default)]
+pub struct Nodes(pub Vec<Node>);
+
+impl Nodes {
+    pub fn new() -> Self {
+        Nodes(Vec::new())
+    }
+
+    pub fn to_const(&self, idx: NodeIdx) -> Result<U256, NodeConstErr> {
+        let me = self.0.get(idx.0).ok_or(NodeConstErr::EmptyNode(idx))?;
+        match me {
+            Node::Constant(v) => Ok(*v),
+            Node::UnoOp(op, a) => Ok(op.eval(self.to_const(NodeIdx(*a))?)),
+            Node::Op(op, a, b) => {
+                Ok(op.eval(self.to_const(NodeIdx(*a))?, self.to_const(NodeIdx(*b))?))
+            }
+            Node::TresOp(op, a, b, c) => Ok(op.eval(
+                self.to_const(NodeIdx(*a))?,
+                self.to_const(NodeIdx(*b))?,
+                self.to_const(NodeIdx(*c))?,
+            )),
+            Node::Input(_) => Err(NodeConstErr::InputSignal),
+            Node::MontConstant(_) => {
+                panic!("MontConstant should not be used here")
+            }
+        }
+    }
+
+    pub fn push(&mut self, n: Node) -> NodeIdx {
+        self.0.push(n);
+        NodeIdx(self.0.len() - 1)
+    }
+
+    pub fn get(&self, idx: NodeIdx) -> Option<&Node> {
+        self.0.get(idx.0)
+    }
+}
+
+impl Deref for Nodes {
+    type Target = Vec<Node>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+#[derive(Debug, Copy, Clone)]
+pub struct NodeIdx(pub usize);
+
+impl From<usize> for NodeIdx {
+    fn from(v: usize) -> Self {
+        NodeIdx(v)
+    }
+}
+
+#[derive(Debug)]
+pub enum NodeConstErr {
+    EmptyNode(NodeIdx),
+    InputSignal,
+}
+
+impl std::fmt::Display for NodeConstErr {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            NodeConstErr::EmptyNode(idx) => {
+                write!(f, "empty node at index {}", idx.0)
+            }
+            NodeConstErr::InputSignal => {
+                write!(f, "input signal is not a constant")
+            }
+        }
+    }
+}
+
+impl Error for NodeConstErr {}
+
+fn compute_shl_uint(a: U256, b: U256) -> U256 {
+    debug_assert!(b.lt(&U256::from(256)));
+    let ls_limb = b.as_limbs()[0];
+    a.shl(ls_limb as usize)
+}
+
+fn compute_shr_uint(a: U256, b: U256) -> U256 {
+    debug_assert!(b.lt(&U256::from(256)));
+    let ls_limb = b.as_limbs()[0];
+    a.shr(ls_limb as usize)
+}
+
+/// All references must be backwards.
+fn assert_valid(nodes: &[Node]) {
+    for (i, &node) in nodes.iter().enumerate() {
+        if let Node::Op(_, a, b) = node {
+            assert!(a < i);
+            assert!(b < i);
+        } else if let Node::UnoOp(_, a) = node {
+            assert!(a < i);
+        } else if let Node::TresOp(_, a, b, c) = node {
+            assert!(a < i);
+            assert!(b < i);
+            assert!(c < i);
+        }
+    }
+}
+
+pub fn optimize(nodes: &mut Vec<Node>, outputs: &mut [usize]) {
+    tree_shake(nodes, outputs);
+    propagate(nodes);
+    value_numbering(nodes, outputs);
+    constants(nodes);
+    tree_shake(nodes, outputs);
+    montgomery_form(nodes);
+}
+
+pub fn evaluate(nodes: &[Node], inputs: &[U256], outputs: &[usize]) -> Vec<Fr> {
+    // assert_valid(nodes);
+
+    // Evaluate the graph.
+    let mut values = Vec::with_capacity(nodes.len());
+    for &node in nodes.iter() {
+        let value = match node {
+            Node::Constant(c) => u256_to_fr(&c),
+            Node::MontConstant(c) => c,
+            Node::Input(i) => u256_to_fr(&inputs[i]),
+            Node::Op(op, a, b) => op.eval_fr(values[a], values[b]),
+            Node::UnoOp(op, a) => op.eval_fr(values[a]),
+            Node::TresOp(op, a, b, c) => op.eval_fr(values[a], values[b], values[c]),
+        };
+        values.push(value);
+    }
+
+    // Convert from Montgomery form and return the outputs.
+    let mut out = vec![Fr::from(0); outputs.len()];
+    for i in 0..outputs.len() {
+        out[i] = values[outputs[i]];
+    }
+
+    out
+}
+
+/// Constant propagation
+pub fn propagate(nodes: &mut [Node]) {
+    assert_valid(nodes);
+    for i in 0..nodes.len() {
+        if let Node::Op(op, a, b) = nodes[i] {
+            if let (Node::Constant(va), Node::Constant(vb)) = (nodes[a], nodes[b]) {
+                nodes[i] = Node::Constant(op.eval(va, vb));
+            } else if a == b {
+                // Not constant but equal
+                use Operation::*;
+                if let Some(c) = match op {
+                    Eq | Leq | Geq => Some(true),
+                    Neq | Lt | Gt => Some(false),
+                    _ => None,
+                } {
+                    nodes[i] = Node::Constant(U256::from(c));
+                }
+            }
+        } else if let Node::UnoOp(op, a) = nodes[i] {
+            if let Node::Constant(va) = nodes[a] {
+                nodes[i] = Node::Constant(op.eval(va));
+            }
+        } else if let Node::TresOp(op, a, b, c) = nodes[i] {
+            if let (Node::Constant(va), Node::Constant(vb), Node::Constant(vc)) =
+                (nodes[a], nodes[b], nodes[c])
+            {
+                nodes[i] = Node::Constant(op.eval(va, vb, vc));
+            }
+        }
+    }
+}
+
+/// Remove unused nodes
+pub fn tree_shake(nodes: &mut Vec<Node>, outputs: &mut [usize]) {
+    assert_valid(nodes);
+
+    // Mark all nodes that are used.
+    let mut used = vec![false; nodes.len()];
+    for &i in outputs.iter() {
+        used[i] = true;
+    }
+
+    // Work backwards from end as all references are backwards.
+    for i in (0..nodes.len()).rev() {
+        if used[i] {
+            if let Node::Op(_, a, b) = nodes[i] {
+                used[a] = true;
+                used[b] = true;
+            }
+            if let Node::UnoOp(_, a) = nodes[i] {
+                used[a] = true;
+            }
+            if let Node::TresOp(_, a, b, c) = nodes[i] {
+                used[a] = true;
+                used[b] = true;
+                used[c] = true;
+            }
+        }
+    }
+
+    // Remove unused nodes
+    let n = nodes.len();
+    let mut retain = used.iter();
+    nodes.retain(|_| *retain.next().unwrap());
+
+    // Renumber references.
+    let mut renumber = vec![None; n];
+    let mut index = 0;
+    for (i, &used) in used.iter().enumerate() {
+        if used {
+            renumber[i] = Some(index);
+            index += 1;
+        }
+    }
+    assert_eq!(index, nodes.len());
+    for (&used, renumber) in used.iter().zip(renumber.iter()) {
+        assert_eq!(used, renumber.is_some());
+    }
+
+    // Renumber references.
+    for node in nodes.iter_mut() {
+        if let Node::Op(_, a, b) = node {
+            *a = renumber[*a].unwrap();
+            *b = renumber[*b].unwrap();
+        }
+        if let Node::UnoOp(_, a) = node {
+            *a = renumber[*a].unwrap();
+        }
+        if let Node::TresOp(_, a, b, c) = node {
+            *a = renumber[*a].unwrap();
+            *b = renumber[*b].unwrap();
+            *c = renumber[*c].unwrap();
+        }
+    }
+    for output in outputs.iter_mut() {
+        *output = renumber[*output].unwrap();
+    }
+}
+
+/// Randomly evaluate the graph
+fn random_eval(nodes: &mut [Node]) -> Vec<U256> {
+    let mut rng = rand::thread_rng();
+    let mut values = Vec::with_capacity(nodes.len());
+    let mut inputs = HashMap::new();
+    let mut prfs = HashMap::new();
+    let mut prfs_uno = HashMap::new();
+    let mut prfs_tres = HashMap::new();
+    for node in nodes.iter() {
+        use Operation::*;
+        let value = match node {
+            // Constants evaluate to themselves
+            Node::Constant(c) => *c,
+
+            Node::MontConstant(_) => unimplemented!("should not be used"),
+
+            // Algebraic Ops are evaluated directly
+            // Since the field is large, by Swartz-Zippel if
+            // two values are the same then they are likely algebraically equal.
+            Node::Op(op @ (Add | Sub | Mul), a, b) => op.eval(values[*a], values[*b]),
+
+            // Input and non-algebraic ops are random functions
+            // TODO: https://github.com/recmo/uint/issues/95 and use .gen_range(..M)
+            Node::Input(i) => *inputs.entry(*i).or_insert_with(|| rng.gen::<U256>() % M),
+            Node::Op(op, a, b) => *prfs
+                .entry((*op, values[*a], values[*b]))
+                .or_insert_with(|| rng.gen::<U256>() % M),
+            Node::UnoOp(op, a) => *prfs_uno
+                .entry((*op, values[*a]))
+                .or_insert_with(|| rng.gen::<U256>() % M),
+            Node::TresOp(op, a, b, c) => *prfs_tres
+                .entry((*op, values[*a], values[*b], values[*c]))
+                .or_insert_with(|| rng.gen::<U256>() % M),
+        };
+        values.push(value);
+    }
+    values
+}
+
+/// Value numbering
+pub fn value_numbering(nodes: &mut [Node], outputs: &mut [usize]) {
+    assert_valid(nodes);
+
+    // Evaluate the graph in random field elements.
+    let values = random_eval(nodes);
+
+    // Find all nodes with the same value.
+    let mut value_map = HashMap::new();
+    for (i, &value) in values.iter().enumerate() {
+        value_map.entry(value).or_insert_with(Vec::new).push(i);
+    }
+
+    // For nodes that are the same, pick the first index.
+    let renumber: Vec<_> = values.into_iter().map(|v| value_map[&v][0]).collect();
+
+    // Renumber references.
+    for node in nodes.iter_mut() {
+        if let Node::Op(_, a, b) = node {
+            *a = renumber[*a];
+            *b = renumber[*b];
+        }
+        if let Node::UnoOp(_, a) = node {
+            *a = renumber[*a];
+        }
+        if let Node::TresOp(_, a, b, c) = node {
+            *a = renumber[*a];
+            *b = renumber[*b];
+            *c = renumber[*c];
+        }
+    }
+    for output in outputs.iter_mut() {
+        *output = renumber[*output];
+    }
+}
+
+/// Probabilistic constant determination
+pub fn constants(nodes: &mut [Node]) {
+    assert_valid(nodes);
+
+    // Evaluate the graph in random field elements.
+    let values_a = random_eval(nodes);
+    let values_b = random_eval(nodes);
+
+    // Find all nodes with the same value.
+    for i in 0..nodes.len() {
+        if let Node::Constant(_) = nodes[i] {
+            continue;
+        }
+        if values_a[i] == values_b[i] {
+            nodes[i] = Node::Constant(values_a[i]);
+        }
+    }
+}
+
+/// Convert to Montgomery form
+pub fn montgomery_form(nodes: &mut [Node]) {
+    for node in nodes.iter_mut() {
+        use Node::*;
+        use Operation::*;
+        match node {
+            Constant(c) => *node = MontConstant(u256_to_fr(c)),
+            MontConstant(..) => (),
+            Input(..) => (),
+            Op(
+                Mul | Div | Add | Sub | Idiv | Mod | Eq | Neq | Lt | Gt | Leq | Geq | Land | Lor
+                | Shl | Shr | Bor | Band | Bxor,
+                ..,
+            ) => (),
+            Op(op @ Pow, ..) => unimplemented!("Operators Montgomery form: {:?}", op),
+            UnoOp(UnoOperation::Neg, ..) => (),
+            UnoOp(op, ..) => unimplemented!("Uno Operators Montgomery form: {:?}", op),
+            TresOp(TresOperation::TernCond, ..) => (),
+        }
+    }
+}
+
+fn shl(a: Fr, b: Fr) -> Fr {
+    if b.is_zero() {
+        return a;
+    }
+
+    if b.cmp(&Fr::from(Fr::MODULUS_BIT_SIZE)).is_ge() {
+        return Fr::zero();
+    }
+
+    let n = b.into_bigint().0[0] as u32;
+    let a = a.into_bigint();
+    Fr::from_bigint(a << n).unwrap()
+}
+
+fn shr(a: Fr, b: Fr) -> Fr {
+    if b.is_zero() {
+        return a;
+    }
+
+    match b.cmp(&Fr::from(254u64)) {
+        Ordering::Equal => return Fr::zero(),
+        Ordering::Greater => return Fr::zero(),
+        _ => (),
+    };
+
+    let mut n = b.into_bigint().to_bytes_le()[0];
+    let mut result = a.into_bigint();
+    let c = result.as_mut();
+    while n >= 64 {
+        for i in 0..3 {
+            c[i as usize] = c[(i + 1) as usize];
+        }
+        c[3] = 0;
+        n -= 64;
+    }
+
+    if n == 0 {
+        return Fr::from_bigint(result).unwrap();
+    }
+
+    let mask: u64 = (1 << n) - 1;
+    let mut carrier: u64 = c[3] & mask;
+    c[3] >>= n;
+    for i in (0..3).rev() {
+        let new_carrier = c[i] & mask;
+        c[i] = (c[i] >> n) | (carrier << (64 - n));
+        carrier = new_carrier;
+    }
+    Fr::from_bigint(result).unwrap()
+}
+
+fn bit_and(a: Fr, b: Fr) -> Fr {
+    let a = a.into_bigint();
+    let b = b.into_bigint();
+    let c: [u64; 4] = [
+        a.0[0] & b.0[0],
+        a.0[1] & b.0[1],
+        a.0[2] & b.0[2],
+        a.0[3] & b.0[3],
+    ];
+    let mut d: BigInt<4> = BigInt::new(c);
+    if d > Fr::MODULUS {
+        d.sub_with_borrow(&Fr::MODULUS);
+    }
+
+    Fr::from_bigint(d).unwrap()
+}
+
+fn bit_or(a: Fr, b: Fr) -> Fr {
+    let a = a.into_bigint();
+    let b = b.into_bigint();
+    let c: [u64; 4] = [
+        a.0[0] | b.0[0],
+        a.0[1] | b.0[1],
+        a.0[2] | b.0[2],
+        a.0[3] | b.0[3],
+    ];
+    let mut d: BigInt<4> = BigInt::new(c);
+    if d > Fr::MODULUS {
+        d.sub_with_borrow(&Fr::MODULUS);
+    }
+
+    Fr::from_bigint(d).unwrap()
+}
+
+fn bit_xor(a: Fr, b: Fr) -> Fr {
+    let a = a.into_bigint();
+    let b = b.into_bigint();
+    let c: [u64; 4] = [
+        a.0[0] ^ b.0[0],
+        a.0[1] ^ b.0[1],
+        a.0[2] ^ b.0[2],
+        a.0[3] ^ b.0[3],
+    ];
+    let mut d: BigInt<4> = BigInt::new(c);
+    if d > Fr::MODULUS {
+        d.sub_with_borrow(&Fr::MODULUS);
+    }
+
+    Fr::from_bigint(d).unwrap()
+}
+
+// M / 2
+const HALF_M: U256 =
+    uint!(10944121435919637611123202872628637544274182200208017171849102093287904247808_U256);
+
+fn u_gte(a: &U256, b: &U256) -> U256 {
+    let a_neg = &HALF_M < a;
+    let b_neg = &HALF_M < b;
+
+    match (a_neg, b_neg) {
+        (false, false) => U256::from(a >= b),
+        (true, false) => uint!(0_U256),
+        (false, true) => uint!(1_U256),
+        (true, true) => U256::from(a >= b),
+    }
+}
+
+fn u_lte(a: &U256, b: &U256) -> U256 {
+    let a_neg = &HALF_M < a;
+    let b_neg = &HALF_M < b;
+
+    match (a_neg, b_neg) {
+        (false, false) => U256::from(a <= b),
+        (true, false) => uint!(1_U256),
+        (false, true) => uint!(0_U256),
+        (true, true) => U256::from(a <= b),
+    }
+}
+
+fn u_gt(a: &U256, b: &U256) -> U256 {
+    let a_neg = &HALF_M < a;
+    let b_neg = &HALF_M < b;
+
+    match (a_neg, b_neg) {
+        (false, false) => U256::from(a > b),
+        (true, false) => uint!(0_U256),
+        (false, true) => uint!(1_U256),
+        (true, true) => U256::from(a > b),
+    }
+}
+
+fn u_lt(a: &U256, b: &U256) -> U256 {
+    let a_neg = &HALF_M < a;
+    let b_neg = &HALF_M < b;
+
+    match (a_neg, b_neg) {
+        (false, false) => U256::from(a < b),
+        (true, false) => uint!(1_U256),
+        (false, true) => uint!(0_U256),
+        (true, true) => U256::from(a < b),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use ruint::uint;
+    use std::ops::Div;
+    use std::str::FromStr;
+
+    #[test]
+    fn test_ok() {
+        let a = Fr::from(4u64);
+        let b = Fr::from(2u64);
+        let c = shl(a, b);
+        assert_eq!(c.cmp(&Fr::from(16u64)), Ordering::Equal)
+    }
+
+    #[test]
+    fn test_div() {
+        assert_eq!(
+            Operation::Div.eval_fr(Fr::from(2u64), Fr::from(3u64)),
+            Fr::from_str(
+                "7296080957279758407415468581752425029516121466805344781232734728858602831873"
+            )
+            .unwrap()
+        );
+
+        assert_eq!(
+            Operation::Div.eval_fr(Fr::from(6u64), Fr::from(2u64)),
+            Fr::from_str("3").unwrap()
+        );
+
+        assert_eq!(
+            Operation::Div.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Fr::from_str(
+                "10944121435919637611123202872628637544274182200208017171849102093287904247812"
+            )
+            .unwrap()
+        );
+    }
+
+    #[test]
+    fn test_idiv() {
+        assert_eq!(
+            Operation::Idiv.eval_fr(Fr::from(2u64), Fr::from(3u64)),
+            Fr::from_str("0").unwrap()
+        );
+
+        assert_eq!(
+            Operation::Idiv.eval_fr(Fr::from(6u64), Fr::from(2u64)),
+            Fr::from_str("3").unwrap()
+        );
+
+        assert_eq!(
+            Operation::Idiv.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Fr::from_str("3").unwrap()
+        );
+    }
+
+    #[test]
+    fn test_fr_mod() {
+        assert_eq!(
+            Operation::Mod.eval_fr(Fr::from(7u64), Fr::from(2u64)),
+            Fr::from_str("1").unwrap()
+        );
+
+        assert_eq!(
+            Operation::Mod.eval_fr(Fr::from(7u64), Fr::from(9u64)),
+            Fr::from_str("7").unwrap()
+        );
+    }
+
+    #[test]
+    fn test_u_gte() {
+        let result = u_gte(&uint!(10_U256), &uint!(3_U256));
+        assert_eq!(result, uint!(1_U256));
+
+        let result = u_gte(&uint!(3_U256), &uint!(3_U256));
+        assert_eq!(result, uint!(1_U256));
+
+        let result = u_gte(&uint!(2_U256), &uint!(3_U256));
+        assert_eq!(result, uint!(0_U256));
+
+        // -1 >= 3 => 0
+        let result = u_gte(
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495616_U256
+            ),
+            &uint!(3_U256),
+        );
+        assert_eq!(result, uint!(0_U256));
+
+        // -1 >= -2 => 1
+        let result = u_gte(
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495616_U256
+            ),
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495615_U256
+            ),
+        );
+        assert_eq!(result, uint!(1_U256));
+
+        // -2 >= -1 => 0
+        let result = u_gte(
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495615_U256
+            ),
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495616_U256
+            ),
+        );
+        assert_eq!(result, uint!(0_U256));
+
+        // -2 == -2 => 1
+        let result = u_gte(
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495615_U256
+            ),
+            &uint!(
+                21888242871839275222246405745257275088548364400416034343698204186575808495615_U256
+            ),
+        );
+        assert_eq!(result, uint!(1_U256));
+    }
+
+    #[test]
+    fn test_x() {
+        let x = M.div(uint!(2_U256));
+
+        println!("x: {:?}", x.as_limbs());
+        println!("x: {}", M);
+    }
+
+    #[test]
+    fn test_2() {
+        let nodes: Vec<Node> = vec![];
+        // let node = nodes[0];
+        let node = nodes.get(0);
+        println!("{:?}", node);
+    }
+}

rln/src/circuit/iden3calc/proto.rs

@@ -0,0 +1,117 @@
+// This file has been generated by prost-build during compilation of the code by iden3
+// and modified manually. The *.proto file used to generate this on can be found here:
+// https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/protos/messages.proto
+
+use std::collections::HashMap;
+
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct BigUInt {
+    #[prost(bytes = "vec", tag = "1")]
+    pub value_le: Vec<u8>,
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub struct InputNode {
+    #[prost(uint32, tag = "1")]
+    pub idx: u32,
+}
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct ConstantNode {
+    #[prost(message, optional, tag = "1")]
+    pub value: Option<BigUInt>,
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub struct UnoOpNode {
+    #[prost(enumeration = "UnoOp", tag = "1")]
+    pub op: i32,
+    #[prost(uint32, tag = "2")]
+    pub a_idx: u32,
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub struct DuoOpNode {
+    #[prost(enumeration = "DuoOp", tag = "1")]
+    pub op: i32,
+    #[prost(uint32, tag = "2")]
+    pub a_idx: u32,
+    #[prost(uint32, tag = "3")]
+    pub b_idx: u32,
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub struct TresOpNode {
+    #[prost(enumeration = "TresOp", tag = "1")]
+    pub op: i32,
+    #[prost(uint32, tag = "2")]
+    pub a_idx: u32,
+    #[prost(uint32, tag = "3")]
+    pub b_idx: u32,
+    #[prost(uint32, tag = "4")]
+    pub c_idx: u32,
+}
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct Node {
+    #[prost(oneof = "node::Node", tags = "1, 2, 3, 4, 5")]
+    pub node: Option<node::Node>,
+}
+/// Nested message and enum types in `Node`.
+pub mod node {
+    #[derive(Clone, PartialEq, ::prost::Oneof)]
+    pub enum Node {
+        #[prost(message, tag = "1")]
+        Input(super::InputNode),
+        #[prost(message, tag = "2")]
+        Constant(super::ConstantNode),
+        #[prost(message, tag = "3")]
+        UnoOp(super::UnoOpNode),
+        #[prost(message, tag = "4")]
+        DuoOp(super::DuoOpNode),
+        #[prost(message, tag = "5")]
+        TresOp(super::TresOpNode),
+    }
+}
+#[derive(Clone, Copy, PartialEq, ::prost::Message)]
+pub struct SignalDescription {
+    #[prost(uint32, tag = "1")]
+    pub offset: u32,
+    #[prost(uint32, tag = "2")]
+    pub len: u32,
+}
+#[derive(Clone, PartialEq, ::prost::Message)]
+pub struct GraphMetadata {
+    #[prost(uint32, repeated, tag = "1")]
+    pub witness_signals: Vec<u32>,
+    #[prost(map = "string, message", tag = "2")]
+    pub inputs: HashMap<String, SignalDescription>,
+}
+#[derive(Clone, Copy, Debug, PartialEq, ::prost::Enumeration)]
+pub enum DuoOp {
+    Mul = 0,
+    Div = 1,
+    Add = 2,
+    Sub = 3,
+    Pow = 4,
+    Idiv = 5,
+    Mod = 6,
+    Eq = 7,
+    Neq = 8,
+    Lt = 9,
+    Gt = 10,
+    Leq = 11,
+    Geq = 12,
+    Land = 13,
+    Lor = 14,
+    Shl = 15,
+    Shr = 16,
+    Bor = 17,
+    Band = 18,
+    Bxor = 19,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, ::prost::Enumeration)]
+pub enum UnoOp {
+    Neg = 0,
+    Id = 1,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq, ::prost::Enumeration)]
+pub enum TresOp {
+    TernCond = 0,
+}

rln/src/circuit/iden3calc/storage.rs

@@ -0,0 +1,497 @@
+// This file is based on the code by iden3. Its preimage can be found here:
+// https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/src/storage.rs
+
+use ark_bn254::Fr;
+use ark_ff::PrimeField;
+use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
+use prost::Message;
+use std::io::{Read, Write};
+
+use crate::circuit::iden3calc::{
+    graph,
+    graph::{Operation, TresOperation, UnoOperation},
+    proto, InputSignalsInfo,
+};
+
+// format of the wtns.graph file:
+// + magic line: wtns.graph.001
+// + 4 bytes unsigned LE 32-bit integer: number of nodes
+// + series of protobuf serialized nodes. Each node prefixed by varint length
+// + protobuf serialized GraphMetadata
+// + 8 bytes unsigned LE 64-bit integer: offset of GraphMetadata message
+
+const WITNESSCALC_GRAPH_MAGIC: &[u8] = b"wtns.graph.001";
+
+const MAX_VARINT_LENGTH: usize = 10;
+
+impl From<proto::Node> for graph::Node {
+    fn from(value: proto::Node) -> Self {
+        match value.node.unwrap() {
+            proto::node::Node::Input(input_node) => graph::Node::Input(input_node.idx as usize),
+            proto::node::Node::Constant(constant_node) => {
+                let i = constant_node.value.unwrap();
+                graph::Node::MontConstant(Fr::from_le_bytes_mod_order(i.value_le.as_slice()))
+            }
+            proto::node::Node::UnoOp(uno_op_node) => {
+                let op = proto::UnoOp::try_from(uno_op_node.op).unwrap();
+                graph::Node::UnoOp(op.into(), uno_op_node.a_idx as usize)
+            }
+            proto::node::Node::DuoOp(duo_op_node) => {
+                let op = proto::DuoOp::try_from(duo_op_node.op).unwrap();
+                graph::Node::Op(
+                    op.into(),
+                    duo_op_node.a_idx as usize,
+                    duo_op_node.b_idx as usize,
+                )
+            }
+            proto::node::Node::TresOp(tres_op_node) => {
+                let op = proto::TresOp::try_from(tres_op_node.op).unwrap();
+                graph::Node::TresOp(
+                    op.into(),
+                    tres_op_node.a_idx as usize,
+                    tres_op_node.b_idx as usize,
+                    tres_op_node.c_idx as usize,
+                )
+            }
+        }
+    }
+}
+
+impl From<&graph::Node> for proto::node::Node {
+    fn from(node: &graph::Node) -> Self {
+        match node {
+            graph::Node::Input(i) => proto::node::Node::Input(proto::InputNode { idx: *i as u32 }),
+            graph::Node::Constant(_) => {
+                panic!("We are not supposed to write Constant to the witnesscalc graph. All Constant should be converted to MontConstant.");
+            }
+            graph::Node::UnoOp(op, a) => {
+                let op = proto::UnoOp::from(op);
+                proto::node::Node::UnoOp(proto::UnoOpNode {
+                    op: op as i32,
+                    a_idx: *a as u32,
+                })
+            }
+            graph::Node::Op(op, a, b) => proto::node::Node::DuoOp(proto::DuoOpNode {
+                op: proto::DuoOp::from(op) as i32,
+                a_idx: *a as u32,
+                b_idx: *b as u32,
+            }),
+            graph::Node::TresOp(op, a, b, c) => proto::node::Node::TresOp(proto::TresOpNode {
+                op: proto::TresOp::from(op) as i32,
+                a_idx: *a as u32,
+                b_idx: *b as u32,
+                c_idx: *c as u32,
+            }),
+            graph::Node::MontConstant(c) => {
+                let bi = Into::<num_bigint::BigUint>::into(*c);
+                let i = proto::BigUInt {
+                    value_le: bi.to_bytes_le(),
+                };
+                proto::node::Node::Constant(proto::ConstantNode { value: Some(i) })
+            }
+        }
+    }
+}
+
+impl From<proto::UnoOp> for UnoOperation {
+    fn from(value: proto::UnoOp) -> Self {
+        match value {
+            proto::UnoOp::Neg => UnoOperation::Neg,
+            proto::UnoOp::Id => UnoOperation::Id,
+        }
+    }
+}
+
+impl From<proto::DuoOp> for Operation {
+    fn from(value: proto::DuoOp) -> Self {
+        match value {
+            proto::DuoOp::Mul => Operation::Mul,
+            proto::DuoOp::Div => Operation::Div,
+            proto::DuoOp::Add => Operation::Add,
+            proto::DuoOp::Sub => Operation::Sub,
+            proto::DuoOp::Pow => Operation::Pow,
+            proto::DuoOp::Idiv => Operation::Idiv,
+            proto::DuoOp::Mod => Operation::Mod,
+            proto::DuoOp::Eq => Operation::Eq,
+            proto::DuoOp::Neq => Operation::Neq,
+            proto::DuoOp::Lt => Operation::Lt,
+            proto::DuoOp::Gt => Operation::Gt,
+            proto::DuoOp::Leq => Operation::Leq,
+            proto::DuoOp::Geq => Operation::Geq,
+            proto::DuoOp::Land => Operation::Land,
+            proto::DuoOp::Lor => Operation::Lor,
+            proto::DuoOp::Shl => Operation::Shl,
+            proto::DuoOp::Shr => Operation::Shr,
+            proto::DuoOp::Bor => Operation::Bor,
+            proto::DuoOp::Band => Operation::Band,
+            proto::DuoOp::Bxor => Operation::Bxor,
+        }
+    }
+}
+
+impl From<proto::TresOp> for graph::TresOperation {
+    fn from(value: proto::TresOp) -> Self {
+        match value {
+            proto::TresOp::TernCond => TresOperation::TernCond,
+        }
+    }
+}
+
+pub fn serialize_witnesscalc_graph<T: Write>(
+    mut w: T,
+    nodes: &Vec<graph::Node>,
+    witness_signals: &[usize],
+    input_signals: &InputSignalsInfo,
+) -> std::io::Result<()> {
+    let mut ptr = 0usize;
+    w.write_all(WITNESSCALC_GRAPH_MAGIC).unwrap();
+    ptr += WITNESSCALC_GRAPH_MAGIC.len();
+
+    w.write_u64::<LittleEndian>(nodes.len() as u64)?;
+    ptr += 8;
+
+    let metadata = proto::GraphMetadata {
+        witness_signals: witness_signals
+            .iter()
+            .map(|x| *x as u32)
+            .collect::<Vec<u32>>(),
+        inputs: input_signals
+            .iter()
+            .map(|(k, v)| {
+                let sig = proto::SignalDescription {
+                    offset: v.0 as u32,
+                    len: v.1 as u32,
+                };
+                (k.clone(), sig)
+            })
+            .collect(),
+    };
+
+    // capacity of buf should be enough to hold the largest message + 10 bytes
+    // of varint length
+    let mut buf = Vec::with_capacity(metadata.encoded_len() + MAX_VARINT_LENGTH);
+
+    for node in nodes {
+        let node_pb = proto::Node {
+            node: Some(proto::node::Node::from(node)),
+        };
+
+        assert_eq!(buf.len(), 0);
+        node_pb.encode_length_delimited(&mut buf)?;
+        ptr += buf.len();
+
+        w.write_all(&buf)?;
+        buf.clear();
+    }
+
+    metadata.encode_length_delimited(&mut buf)?;
+    w.write_all(&buf)?;
+    buf.clear();
+
+    w.write_u64::<LittleEndian>(ptr as u64)?;
+
+    Ok(())
+}
+
+fn read_message_length<R: Read>(rw: &mut WriteBackReader<R>) -> std::io::Result<usize> {
+    let mut buf = [0u8; MAX_VARINT_LENGTH];
+    let bytes_read = rw.read(&mut buf)?;
+    if bytes_read == 0 {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::UnexpectedEof,
+            "Unexpected EOF",
+        ));
+    }
+
+    let len_delimiter = prost::decode_length_delimiter(buf.as_ref())?;
+
+    let lnln = prost::length_delimiter_len(len_delimiter);
+
+    if lnln < bytes_read {
+        rw.write_all(&buf[lnln..bytes_read])?;
+    }
+
+    Ok(len_delimiter)
+}
+
+fn read_message<R: Read, M: Message + std::default::Default>(
+    rw: &mut WriteBackReader<R>,
+) -> std::io::Result<M> {
+    let ln = read_message_length(rw)?;
+    let mut buf = vec![0u8; ln];
+    let bytes_read = rw.read(&mut buf)?;
+    if bytes_read != ln {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::UnexpectedEof,
+            "Unexpected EOF",
+        ));
+    }
+
+    let msg = prost::Message::decode(&buf[..])?;
+
+    Ok(msg)
+}
+
+pub fn deserialize_witnesscalc_graph(
+    r: impl Read,
+) -> std::io::Result<(Vec<graph::Node>, Vec<usize>, InputSignalsInfo)> {
+    let mut br = WriteBackReader::new(r);
+    let mut magic = [0u8; WITNESSCALC_GRAPH_MAGIC.len()];
+
+    br.read_exact(&mut magic)?;
+
+    if !magic.eq(WITNESSCALC_GRAPH_MAGIC) {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            "Invalid magic",
+        ));
+    }
+
+    let nodes_num = br.read_u64::<LittleEndian>()?;
+    let mut nodes = Vec::with_capacity(nodes_num as usize);
+    for _ in 0..nodes_num {
+        let n: proto::Node = read_message(&mut br)?;
+        let n2: graph::Node = n.into();
+        nodes.push(n2);
+    }
+
+    let md: proto::GraphMetadata = read_message(&mut br)?;
+
+    let witness_signals = md
+        .witness_signals
+        .iter()
+        .map(|x| *x as usize)
+        .collect::<Vec<usize>>();
+
+    let input_signals = md
+        .inputs
+        .iter()
+        .map(|(k, v)| (k.clone(), (v.offset as usize, v.len as usize)))
+        .collect::<InputSignalsInfo>();
+
+    Ok((nodes, witness_signals, input_signals))
+}
+
+struct WriteBackReader<R: Read> {
+    reader: R,
+    buffer: Vec<u8>,
+}
+
+impl<R: Read> WriteBackReader<R> {
+    fn new(reader: R) -> Self {
+        WriteBackReader {
+            reader,
+            buffer: Vec::new(),
+        }
+    }
+}
+
+impl<R: Read> Read for WriteBackReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+        if buf.is_empty() {
+            return Ok(0);
+        }
+
+        let mut n = 0usize;
+
+        if !self.buffer.is_empty() {
+            n = std::cmp::min(buf.len(), self.buffer.len());
+            self.buffer[self.buffer.len() - n..]
+                .iter()
+                .rev()
+                .enumerate()
+                .for_each(|(i, x)| {
+                    buf[i] = *x;
+                });
+            self.buffer.truncate(self.buffer.len() - n);
+        }
+
+        while n < buf.len() {
+            let m = self.reader.read(&mut buf[n..])?;
+            if m == 0 {
+                break;
+            }
+            n += m;
+        }
+
+        Ok(n)
+    }
+}
+
+impl<R: Read> Write for WriteBackReader<R> {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        self.buffer.reserve(buf.len());
+        self.buffer.extend(buf.iter().rev());
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use byteorder::ByteOrder;
+    use core::str::FromStr;
+    use graph::{Operation, TresOperation, UnoOperation};
+    use std::collections::HashMap;
+
+    #[test]
+    fn test_read_message() {
+        let mut buf = Vec::new();
+        let n1 = proto::Node {
+            node: Some(proto::node::Node::Input(proto::InputNode { idx: 1 })),
+        };
+        n1.encode_length_delimited(&mut buf).unwrap();
+
+        let n2 = proto::Node {
+            node: Some(proto::node::Node::Input(proto::InputNode { idx: 2 })),
+        };
+        n2.encode_length_delimited(&mut buf).unwrap();
+
+        let mut reader = std::io::Cursor::new(&buf);
+
+        let mut rw = WriteBackReader::new(&mut reader);
+
+        let got_n1: proto::Node = read_message(&mut rw).unwrap();
+        assert!(n1.eq(&got_n1));
+
+        let got_n2: proto::Node = read_message(&mut rw).unwrap();
+        assert!(n2.eq(&got_n2));
+
+        assert_eq!(reader.position(), buf.len() as u64);
+    }
+
+    #[test]
+    fn test_read_message_variant() {
+        let nodes = vec![
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::Input(0))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::MontConstant(
+                    Fr::from_str("1").unwrap(),
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::UnoOp(
+                    UnoOperation::Id,
+                    4,
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::Op(
+                    Operation::Mul,
+                    5,
+                    6,
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::TresOp(
+                    TresOperation::TernCond,
+                    7,
+                    8,
+                    9,
+                ))),
+            },
+        ];
+
+        let mut buf = Vec::new();
+        for n in &nodes {
+            n.encode_length_delimited(&mut buf).unwrap();
+        }
+
+        let mut nodes_got: Vec<proto::Node> = Vec::new();
+        let mut reader = std::io::Cursor::new(&buf);
+        let mut rw = WriteBackReader::new(&mut reader);
+        for _ in 0..nodes.len() {
+            nodes_got.push(read_message(&mut rw).unwrap());
+        }
+
+        assert_eq!(nodes, nodes_got);
+    }
+
+    #[test]
+    fn test_write_back_reader() {
+        let data = [1u8, 2, 3, 4, 5, 6];
+        let mut r = WriteBackReader::new(std::io::Cursor::new(&data));
+
+        let buf = &mut [0u8; 5];
+        r.read(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/circuit/mod.rs

@@ -0,0 +1,159 @@
+// This crate provides interfaces for the zero-knowledge circuit and keys
+
+pub mod error;
+pub mod iden3calc;
+pub mod qap;
+pub mod zkey;
+
+use ::lazy_static::lazy_static;
+use ark_bn254::{
+    Bn254, Fq as ArkFq, Fq2 as ArkFq2, Fr as ArkFr, G1Affine as ArkG1Affine,
+    G1Projective as ArkG1Projective, G2Affine as ArkG2Affine, G2Projective as ArkG2Projective,
+};
+use ark_groth16::ProvingKey;
+use ark_relations::r1cs::ConstraintMatrices;
+use cfg_if::cfg_if;
+
+use crate::circuit::error::ZKeyReadError;
+use crate::circuit::iden3calc::calc_witness;
+
+#[cfg(feature = "arkzkey")]
+use {ark_ff::Field, ark_serialize::CanonicalDeserialize, ark_serialize::CanonicalSerialize};
+
+#[cfg(not(feature = "arkzkey"))]
+use {crate::circuit::zkey::read_zkey, std::io::Cursor};
+
+#[cfg(feature = "arkzkey")]
+pub const ARKZKEY_BYTES: &[u8] = include_bytes!("../../resources/tree_height_20/rln_final.arkzkey");
+
+pub const ZKEY_BYTES: &[u8] = include_bytes!("../../resources/tree_height_20/rln_final.zkey");
+
+#[cfg(not(target_arch = "wasm32"))]
+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")
+                }
+        }
+    };
+}
+
+pub const TEST_TREE_HEIGHT: usize = 20;
+
+// The following types define the pairing friendly elliptic curve, the underlying finite fields and groups default to this module
+// Note that proofs are serialized assuming Fr to be 4x8 = 32 bytes in size. Hence, changing to a curve with different encoding will make proof verification to fail
+pub type Curve = Bn254;
+pub type Fr = ArkFr;
+pub type Fq = ArkFq;
+pub type Fq2 = ArkFq2;
+pub type G1Affine = ArkG1Affine;
+pub type G1Projective = ArkG1Projective;
+pub type G2Affine = ArkG2Affine;
+pub type G2Projective = ArkG2Projective;
+
+// Loads the proving key using a bytes vector
+pub fn zkey_from_raw(
+    zkey_data: &[u8],
+) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>), ZKeyReadError> {
+    if zkey_data.is_empty() {
+        return Err(ZKeyReadError::EmptyBytes);
+    }
+
+    let proving_key_and_matrices = 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() -> &'static (ProvingKey<Curve>, ConstraintMatrices<Fr>) {
+    &ZKEY
+}
+
+pub fn calculate_rln_witness<I: IntoIterator<Item = (String, Vec<Fr>)>>(
+    inputs: I,
+    graph_data: &[u8],
+) -> Vec<Fr> {
+    calc_witness(inputs, graph_data)
+}
+
+#[cfg(not(target_arch = "wasm32"))]
+pub fn graph_from_folder() -> &'static [u8] {
+    GRAPH_BYTES
+}
+
+////////////////////////////////////////////////////////
+// Functions and structs from [arkz-key](https://github.com/zkmopro/ark-zkey/blob/main/src/lib.rs#L106)
+// without print and allow to choose between compressed and uncompressed arkzkey
+////////////////////////////////////////////////////////
+
+#[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>), ZKeyReadError> {
+    if arkzkey_data.is_empty() {
+        return Err(ZKeyReadError::EmptyBytes);
+    }
+
+    let mut cursor = std::io::Cursor::new(arkzkey_data);
+
+    let serialized_proving_key =
+        SerializableProvingKey::deserialize_uncompressed_unchecked(&mut cursor)?;
+
+    let serialized_constraint_matrices =
+        SerializableConstraintMatrices::deserialize_uncompressed_unchecked(&mut cursor)?;
+
+    // Get on right form for API
+    let proving_key: ProvingKey<Bn254> = serialized_proving_key.0;
+    let constraint_matrices: ConstraintMatrices<ark_bn254::Fr> = ConstraintMatrices {
+        num_instance_variables: serialized_constraint_matrices.num_instance_variables,
+        num_witness_variables: serialized_constraint_matrices.num_witness_variables,
+        num_constraints: serialized_constraint_matrices.num_constraints,
+        a_num_non_zero: serialized_constraint_matrices.a_num_non_zero,
+        b_num_non_zero: serialized_constraint_matrices.b_num_non_zero,
+        c_num_non_zero: serialized_constraint_matrices.c_num_non_zero,
+        a: serialized_constraint_matrices.a.data,
+        b: serialized_constraint_matrices.b.data,
+        c: serialized_constraint_matrices.c.data,
+    };
+
+    Ok((proving_key, constraint_matrices))
+}

rln/src/circuit/qap.rs

@@ -0,0 +1,114 @@
+// This file is based on the code by arkworks. Its preimage can be found here:
+// https://github.com/arkworks-rs/circom-compat/blob/3c95ed98e23a408b4d99a53e483a9bba39685a4e/src/circom/qap.rs
+
+use ark_ff::PrimeField;
+use ark_groth16::r1cs_to_qap::{evaluate_constraint, LibsnarkReduction, R1CSToQAP};
+use ark_poly::EvaluationDomain;
+use ark_relations::r1cs::{ConstraintMatrices, ConstraintSystemRef, SynthesisError};
+use ark_std::{cfg_into_iter, cfg_iter, cfg_iter_mut, vec};
+
+/// Implements the witness map used by snarkjs. The arkworks witness map calculates the
+/// coefficients of H through computing (AB-C)/Z in the evaluation domain and going back to the
+/// coefficients domain. snarkjs instead precomputes the Lagrange form of the powers of tau bases
+/// in a domain twice as large and the witness map is computed as the odd coefficients of (AB-C)
+/// in that domain. This serves as HZ when computing the C proof element.
+pub struct CircomReduction;
+
+impl R1CSToQAP for CircomReduction {
+    #[allow(clippy::type_complexity)]
+    fn instance_map_with_evaluation<F: PrimeField, D: EvaluationDomain<F>>(
+        cs: ConstraintSystemRef<F>,
+        t: &F,
+    ) -> Result<(Vec<F>, Vec<F>, Vec<F>, F, usize, usize), SynthesisError> {
+        LibsnarkReduction::instance_map_with_evaluation::<F, D>(cs, t)
+    }
+
+    fn witness_map_from_matrices<F: PrimeField, D: EvaluationDomain<F>>(
+        matrices: &ConstraintMatrices<F>,
+        num_inputs: usize,
+        num_constraints: usize,
+        full_assignment: &[F],
+    ) -> Result<Vec<F>, SynthesisError> {
+        let zero = F::zero();
+        let domain =
+            D::new(num_constraints + num_inputs).ok_or(SynthesisError::PolynomialDegreeTooLarge)?;
+        let domain_size = domain.size();
+
+        let mut a = vec![zero; domain_size];
+        let mut b = vec![zero; domain_size];
+
+        #[allow(unexpected_cfgs)]
+        cfg_iter_mut!(a[..num_constraints])
+            .zip(cfg_iter_mut!(b[..num_constraints]))
+            .zip(cfg_iter!(&matrices.a))
+            .zip(cfg_iter!(&matrices.b))
+            .for_each(|(((a, b), at_i), bt_i)| {
+                *a = evaluate_constraint(at_i, full_assignment);
+                *b = evaluate_constraint(bt_i, full_assignment);
+            });
+
+        {
+            let start = num_constraints;
+            let end = start + num_inputs;
+            a[start..end].clone_from_slice(&full_assignment[..num_inputs]);
+        }
+
+        let mut c = vec![zero; domain_size];
+        #[allow(unexpected_cfgs)]
+        cfg_iter_mut!(c[..num_constraints])
+            .zip(&a)
+            .zip(&b)
+            .for_each(|((c_i, &a), &b)| {
+                *c_i = a * b;
+            });
+
+        domain.ifft_in_place(&mut a);
+        domain.ifft_in_place(&mut b);
+
+        let root_of_unity = {
+            let domain_size_double = 2 * domain_size;
+            let domain_double =
+                D::new(domain_size_double).ok_or(SynthesisError::PolynomialDegreeTooLarge)?;
+            domain_double.element(1)
+        };
+        D::distribute_powers_and_mul_by_const(&mut a, root_of_unity, F::one());
+        D::distribute_powers_and_mul_by_const(&mut b, root_of_unity, F::one());
+
+        domain.fft_in_place(&mut a);
+        domain.fft_in_place(&mut b);
+
+        let mut ab = domain.mul_polynomials_in_evaluation_domain(&a, &b);
+        drop(a);
+        drop(b);
+
+        domain.ifft_in_place(&mut c);
+        D::distribute_powers_and_mul_by_const(&mut c, root_of_unity, F::one());
+        domain.fft_in_place(&mut c);
+
+        #[allow(unexpected_cfgs)]
+        cfg_iter_mut!(ab)
+            .zip(c)
+            .for_each(|(ab_i, c_i)| *ab_i -= &c_i);
+
+        Ok(ab)
+    }
+
+    fn h_query_scalars<F: PrimeField, D: EvaluationDomain<F>>(
+        max_power: usize,
+        t: F,
+        _: F,
+        delta_inverse: F,
+    ) -> Result<Vec<F>, SynthesisError> {
+        // the usual H query has domain-1 powers. Z has domain powers. So HZ has 2*domain-1 powers.
+        #[allow(unexpected_cfgs)]
+        let mut scalars = cfg_into_iter!(0..2 * max_power + 1)
+            .map(|i| delta_inverse * t.pow([i as u64]))
+            .collect::<Vec<_>>();
+        let domain_size = scalars.len();
+        let domain = D::new(domain_size).ok_or(SynthesisError::PolynomialDegreeTooLarge)?;
+        // generate the lagrange coefficients
+        domain.ifft_in_place(&mut scalars);
+        #[allow(unexpected_cfgs)]
+        Ok(cfg_into_iter!(scalars).skip(1).step_by(2).collect())
+    }
+}

rln/src/circuit/zkey.rs

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

rln/src/error.rs

@@ -0,0 +1,77 @@
+use crate::circuit::error::ZKeyReadError;
+use ark_bn254::Fr;
+use ark_relations::r1cs::SynthesisError;
+use ark_serialize::SerializationError;
+use num_bigint::{BigInt, ParseBigIntError};
+use std::array::TryFromSliceError;
+use std::num::TryFromIntError;
+use std::string::FromUtf8Error;
+use thiserror::Error;
+use utils::error::{FromConfigError, ZerokitMerkleTreeError};
+
+#[derive(Debug, thiserror::Error)]
+pub enum ConversionError {
+    #[error("Expected radix 10 or 16")]
+    WrongRadix,
+    #[error("{0}")]
+    ParseBigInt(#[from] ParseBigIntError),
+    #[error("{0}")]
+    ToUsize(#[from] TryFromIntError),
+    #[error("{0}")]
+    FromSlice(#[from] TryFromSliceError),
+}
+
+#[derive(Error, Debug)]
+pub enum ProofError {
+    #[error("{0}")]
+    ProtocolError(#[from] ProtocolError),
+    #[error("Error producing proof: {0}")]
+    SynthesisError(#[from] SynthesisError),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ProtocolError {
+    #[error("{0}")]
+    Conversion(#[from] ConversionError),
+    #[error("Expected to read {0} bytes but read only {1} bytes")]
+    InvalidReadLen(usize, usize),
+    #[error("Cannot convert bigint {0:?} to biguint")]
+    BigUintConversion(BigInt),
+    #[error("{0}")]
+    JsonError(#[from] serde_json::Error),
+    #[error("Message id ({0}) is not within user_message_limit ({1})")]
+    InvalidMessageId(Fr, Fr),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum ComputeIdSecretError {
+    /// Usually it means that the same signal is used to recover the user secret hash
+    #[error("Cannot recover secret: division by zero")]
+    DivisionByZero,
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum RLNError {
+    #[error("I/O error: {0}")]
+    IO(#[from] std::io::Error),
+    #[error("Utf8 error: {0}")]
+    Utf8(#[from] FromUtf8Error),
+    #[error("Serde json error: {0}")]
+    JSON(#[from] serde_json::Error),
+    #[error("Config error: {0}")]
+    Config(#[from] FromConfigError),
+    #[error("Serialization error: {0}")]
+    Serialization(#[from] SerializationError),
+    #[error("Merkle tree error: {0}")]
+    MerkleTree(#[from] ZerokitMerkleTreeError),
+    #[error("ZKey error: {0}")]
+    ZKey(#[from] ZKeyReadError),
+    #[error("Conversion error: {0}")]
+    Conversion(#[from] ConversionError),
+    #[error("Protocol error: {0}")]
+    Protocol(#[from] ProtocolError),
+    #[error("Proof error: {0}")]
+    Proof(#[from] ProofError),
+    #[error("Unable to extract secret")]
+    RecoverSecret(#[from] ComputeIdSecretError),
+}

rln/src/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)*) => {
         {
@@ -157,10 +158,10 @@ impl ProcessArg for *mut RLN {
     }
 }
 
-/// 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)]
@@ -228,17 +229,15 @@ pub extern "C" fn new(ctx: *mut *mut RLN) -> bool {
 #[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) => {
@@ -256,15 +255,13 @@ pub extern "C" fn new_with_params(
 #[cfg(feature = "stateless")]
 #[no_mangle]
 pub extern "C" fn new_with_params(
-    circom_buffer: *const Buffer,
     zkey_buffer: *const Buffer,
-    vk_buffer: *const Buffer,
+    graph_buffer: *const Buffer,
     ctx: *mut *mut RLN,
 ) -> bool {
     match RLN::new_with_params(
-        circom_buffer.process().to_vec(),
         zkey_buffer.process().to_vec(),
-        vk_buffer.process().to_vec(),
+        graph_buffer.process().to_vec(),
     ) {
         Ok(rln) => {
             unsafe { *ctx = Box::into_raw(Box::new(rln)) };

rln/src/hashers.rs

@@ -23,7 +23,7 @@ static POSEIDON: Lazy<Poseidon<Fr>> = Lazy::new(|| Poseidon::<Fr>::from(&ROUND_P
 
 pub fn poseidon_hash(input: &[Fr]) -> Fr {
     POSEIDON
-        .hash(input.to_vec())
+        .hash(input)
         .expect("hash with fixed input size can't fail")
 }
 

rln/src/lib.rs

@@ -1,6 +1,7 @@
-#![allow(dead_code)]
-
 pub mod circuit;
+pub mod error;
+#[cfg(not(target_arch = "wasm32"))]
+pub mod ffi;
 pub mod hashers;
 #[cfg(feature = "pmtree-ft")]
 pub mod pm_tree_adapter;
@@ -10,6 +11,3 @@ pub mod public;
 #[cfg(test)]
 pub mod public_api_tests;
 pub mod utils;
-
-#[cfg(not(target_arch = "wasm32"))]
-pub mod ffi;

rln/src/pm_tree_adapter.rs

@@ -1,17 +1,15 @@
+use serde_json::Value;
 use std::fmt::Debug;
 use std::path::PathBuf;
 use std::str::FromStr;
 
-use color_eyre::{Report, Result};
-use serde_json::Value;
-
-use utils::pmtree::tree::Key;
-use utils::pmtree::{Database, Hasher};
-use utils::*;
-
 use crate::circuit::Fr;
 use crate::hashers::{poseidon_hash, PoseidonHash};
 use crate::utils::{bytes_le_to_fr, fr_to_bytes_le};
+use utils::error::{FromConfigError, ZerokitMerkleTreeError};
+use utils::pmtree::tree::Key;
+use utils::pmtree::{Database, Hasher, PmtreeErrorKind};
+use utils::{pmtree, Config, Mode, SledDB, ZerokitMerkleProof, ZerokitMerkleTree};
 
 const METADATA_KEY: [u8; 8] = *b"metadata";
 
@@ -63,9 +61,9 @@ fn get_tmp() -> bool {
 pub struct PmtreeConfig(Config);
 
 impl FromStr for PmtreeConfig {
-    type Err = Report;
+    type Err = FromConfigError;
 
-    fn from_str(s: &str) -> Result<Self> {
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
         let config: Value = serde_json::from_str(s)?;
 
         let path = config["path"].as_str();
@@ -85,10 +83,7 @@ impl FromStr for PmtreeConfig {
             && temporary.unwrap()
             && path.as_ref().unwrap().exists()
         {
-            return Err(Report::msg(format!(
-                "Path {:?} already exists, cannot use temporary",
-                path.unwrap()
-            )));
+            return Err(FromConfigError::PathExists);
         }
 
         let config = Config::new()
@@ -133,12 +128,16 @@ impl ZerokitMerkleTree for PmTree {
     type Hasher = PoseidonHash;
     type Config = PmtreeConfig;
 
-    fn default(depth: usize) -> Result<Self> {
+    fn default(depth: usize) -> Result<Self, ZerokitMerkleTreeError> {
         let default_config = PmtreeConfig::default();
         PmTree::new(depth, Self::Hasher::default_leaf(), default_config)
     }
 
-    fn new(depth: usize, _default_leaf: FrOf<Self::Hasher>, config: Self::Config) -> Result<Self> {
+    fn new(
+        depth: usize,
+        _default_leaf: FrOf<Self::Hasher>,
+        config: Self::Config,
+    ) -> Result<Self, ZerokitMerkleTreeError> {
         let tree_loaded = pmtree::MerkleTree::load(config.clone().0);
         let tree = match tree_loaded {
             Ok(tree) => tree,
@@ -168,14 +167,12 @@ impl ZerokitMerkleTree for PmTree {
         self.tree.root()
     }
 
-    fn compute_root(&mut self) -> Result<FrOf<Self::Hasher>> {
-        Ok(self.tree.root())
-    }
-
-    fn set(&mut self, index: usize, leaf: FrOf<Self::Hasher>) -> Result<()> {
-        self.tree
-            .set(index, leaf)
-            .map_err(|e| Report::msg(e.to_string()))?;
+    fn set(
+        &mut self,
+        index: usize,
+        leaf: FrOf<Self::Hasher>,
+    ) -> Result<(), ZerokitMerkleTreeError> {
+        self.tree.set(index, leaf)?;
         self.cached_leaves_indices[index] = 1;
         Ok(())
     }
@@ -184,27 +181,31 @@ impl ZerokitMerkleTree for PmTree {
         &mut self,
         start: usize,
         values: I,
-    ) -> Result<()> {
+    ) -> Result<(), ZerokitMerkleTreeError> {
         let v = values.into_iter().collect::<Vec<_>>();
-        self.tree
-            .set_range(start, v.clone().into_iter())
-            .map_err(|e| Report::msg(e.to_string()))?;
+        self.tree.set_range(start, v.clone().into_iter())?;
         for i in start..v.len() {
             self.cached_leaves_indices[i] = 1
         }
         Ok(())
     }
 
-    fn get(&self, index: usize) -> Result<FrOf<Self::Hasher>> {
-        self.tree.get(index).map_err(|e| Report::msg(e.to_string()))
+    fn get(&self, index: usize) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError> {
+        self.tree
+            .get(index)
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
     }
 
-    fn get_subtree_root(&self, n: usize, index: usize) -> Result<FrOf<Self::Hasher>> {
+    fn get_subtree_root(
+        &self,
+        n: usize,
+        index: usize,
+    ) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError> {
         if n > self.depth() {
-            return Err(Report::msg("level exceeds depth size"));
+            return Err(ZerokitMerkleTreeError::InvalidLevel);
         }
         if index >= self.capacity() {
-            return Err(Report::msg("index exceeds set size"));
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
         }
         if n == 0 {
             Ok(self.root())
@@ -235,55 +236,66 @@ impl ZerokitMerkleTree for PmTree {
         start: usize,
         leaves: I,
         indices: J,
-    ) -> Result<()> {
+    ) -> Result<(), ZerokitMerkleTreeError> {
         let leaves = leaves.into_iter().collect::<Vec<_>>();
         let mut indices = indices.into_iter().collect::<Vec<_>>();
         indices.sort();
 
         match (leaves.len(), indices.len()) {
-            (0, 0) => Err(Report::msg("no leaves or indices to be removed")),
+            (0, 0) => Err(ZerokitMerkleTreeError::InvalidLeaf),
             (1, 0) => self.set(start, leaves[0]),
             (0, 1) => self.delete(indices[0]),
-            (_, 0) => self.set_range(start, leaves),
-            (0, _) => self.remove_indices(&indices),
-            (_, _) => self.remove_indices_and_set_leaves(start, leaves, &indices),
+            (_, 0) => self.set_range(start, leaves.into_iter()),
+            (0, _) => self
+                .remove_indices(&indices)
+                .map_err(ZerokitMerkleTreeError::PmtreeErrorKind),
+            (_, _) => self
+                .remove_indices_and_set_leaves(start, leaves, &indices)
+                .map_err(ZerokitMerkleTreeError::PmtreeErrorKind),
         }
     }
 
-    fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<()> {
+    fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<(), ZerokitMerkleTreeError> {
         self.tree
             .update_next(leaf)
-            .map_err(|e| Report::msg(e.to_string()))
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
     }
 
-    fn delete(&mut self, index: usize) -> Result<()> {
+    fn delete(&mut self, index: usize) -> Result<(), ZerokitMerkleTreeError> {
         self.tree
             .delete(index)
-            .map_err(|e| Report::msg(e.to_string()))?;
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)?;
         self.cached_leaves_indices[index] = 0;
         Ok(())
     }
 
-    fn proof(&self, index: usize) -> Result<Self::Proof> {
+    fn proof(&self, index: usize) -> Result<Self::Proof, ZerokitMerkleTreeError> {
         let proof = self.tree.proof(index)?;
         Ok(PmTreeProof { proof })
     }
 
-    fn verify(&self, leaf: &FrOf<Self::Hasher>, witness: &Self::Proof) -> Result<bool> {
+    fn verify(
+        &self,
+        leaf: &FrOf<Self::Hasher>,
+        witness: &Self::Proof,
+    ) -> Result<bool, ZerokitMerkleTreeError> {
         if self.tree.verify(leaf, &witness.proof) {
             Ok(true)
         } else {
-            Err(Report::msg("verify failed"))
+            Err(ZerokitMerkleTreeError::InvalidWitness)
         }
     }
 
-    fn set_metadata(&mut self, metadata: &[u8]) -> Result<()> {
-        self.tree.db.put(METADATA_KEY, metadata.to_vec())?;
+    fn set_metadata(&mut self, metadata: &[u8]) -> Result<(), ZerokitMerkleTreeError> {
+        self.tree
+            .db
+            .put(METADATA_KEY, metadata.to_vec())
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)?;
         self.metadata = metadata.to_vec();
         Ok(())
     }
 
-    fn metadata(&self) -> Result<Vec<u8>> {
+    fn metadata(&self) -> Result<Vec<u8>, ZerokitMerkleTreeError> {
         if !self.metadata.is_empty() {
             return Ok(self.metadata.clone());
         }
@@ -297,8 +309,11 @@ impl ZerokitMerkleTree for PmTree {
         Ok(data.unwrap())
     }
 
-    fn close_db_connection(&mut self) -> Result<()> {
-        self.tree.db.close().map_err(|e| Report::msg(e.to_string()))
+    fn close_db_connection(&mut self) -> Result<(), ZerokitMerkleTreeError> {
+        self.tree
+            .db
+            .close()
+            .map_err(ZerokitMerkleTreeError::PmtreeErrorKind)
     }
 }
 
@@ -306,15 +321,13 @@ type PmTreeHasher = <PmTree as ZerokitMerkleTree>::Hasher;
 type FrOfPmTreeHasher = FrOf<PmTreeHasher>;
 
 impl PmTree {
-    fn remove_indices(&mut self, indices: &[usize]) -> Result<()> {
+    fn remove_indices(&mut self, indices: &[usize]) -> Result<(), PmtreeErrorKind> {
         let start = indices[0];
         let end = indices.last().unwrap() + 1;
 
         let new_leaves = (start..end).map(|_| PmTreeHasher::default_leaf());
 
-        self.tree
-            .set_range(start, new_leaves)
-            .map_err(|e| Report::msg(e.to_string()))?;
+        self.tree.set_range(start, new_leaves)?;
 
         for i in start..end {
             self.cached_leaves_indices[i] = 0
@@ -327,7 +340,7 @@ impl PmTree {
         start: usize,
         leaves: Vec<FrOfPmTreeHasher>,
         indices: &[usize],
-    ) -> Result<()> {
+    ) -> Result<(), PmtreeErrorKind> {
         let min_index = *indices.first().unwrap();
         let max_index = start + leaves.len();
 
@@ -344,9 +357,7 @@ impl PmTree {
             set_values[start - min_index + i] = leaf;
         }
 
-        self.tree
-            .set_range(start, set_values)
-            .map_err(|e| Report::msg(e.to_string()))?;
+        self.tree.set_range(start, set_values)?;
 
         for i in indices {
             self.cached_leaves_indices[*i] = 0;

rln/src/poseidon_tree.rs

@@ -4,26 +4,33 @@
 
 use cfg_if::cfg_if;
 
-cfg_if! {
-    if #[cfg(feature = "pmtree-ft")] {
-        use crate::pm_tree_adapter::*;
-    } else {
-        use crate::hashers::{PoseidonHash};
-        use utils::merkle_tree::*;
-    }
-}
-
 // The zerokit RLN default Merkle tree implementation is the OptimalMerkleTree.
 // To switch to FullMerkleTree implementation, it is enough to enable the fullmerkletree feature
 
 cfg_if! {
     if #[cfg(feature = "fullmerkletree")] {
+
+        use utils::{
+            FullMerkleTree,
+            FullMerkleProof,
+        };
+        use crate::hashers::PoseidonHash;
+
         pub type PoseidonTree = FullMerkleTree<PoseidonHash>;
         pub type MerkleProof = FullMerkleProof<PoseidonHash>;
     } else if #[cfg(feature = "pmtree-ft")] {
+        use crate::pm_tree_adapter::{PmTree, PmTreeProof};
+
         pub type PoseidonTree =  PmTree;
         pub type MerkleProof = PmTreeProof;
     } else {
+
+        use crate::hashers::{PoseidonHash};
+        use utils::{
+            OptimalMerkleTree,
+            OptimalMerkleProof,
+        };
+
         pub type PoseidonTree = OptimalMerkleTree<PoseidonHash>;
         pub type MerkleProof = OptimalMerkleProof<PoseidonHash>;
     }

rln/src/protocol.rs

@@ -1,32 +1,29 @@
 // This crate collects all the underlying primitives used to implement RLN
 
-use ark_circom::{CircomReduction, WitnessCalculator};
+use ark_bn254::Fr;
+use ark_ff::AdditiveGroup;
 use ark_groth16::{prepare_verifying_key, Groth16, Proof as ArkProof, ProvingKey, VerifyingKey};
 use ark_relations::r1cs::ConstraintMatrices;
-use ark_relations::r1cs::SynthesisError;
 use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
 use ark_std::{rand::thread_rng, UniformRand};
-use color_eyre::{Report, Result};
 use num_bigint::BigInt;
 use rand::{Rng, SeedableRng};
 use rand_chacha::ChaCha20Rng;
 use serde::{Deserialize, Serialize};
-#[cfg(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::poseidon_tree::*;
+use crate::circuit::{calculate_rln_witness, qap::CircomReduction, Curve};
+use crate::error::{ComputeIdSecretError, ConversionError, ProofError, ProtocolError};
+use crate::hashers::{hash_to_field, poseidon_hash};
+use crate::poseidon_tree::{MerkleProof, PoseidonTree};
 use crate::public::RLN_IDENTIFIER;
-use crate::utils::*;
-use cfg_if::cfg_if;
+use crate::utils::{
+    bytes_le_to_fr, bytes_le_to_vec_fr, bytes_le_to_vec_u8, fr_byte_size, fr_to_bytes_le,
+    normalize_usize, to_bigint, vec_fr_to_bytes_le, vec_u8_to_bytes_le,
+};
 use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
-
 ///////////////////////////////////////////////////////
 // RLN Witness data structure and utility functions
 ///////////////////////////////////////////////////////
@@ -103,18 +100,26 @@ 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`.
-pub fn serialize_witness(rln_witness: &RLNWitnessInput) -> Result<Vec<u8>> {
+/// 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>, ProtocolError> {
+    // 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)
 }
@@ -124,7 +129,7 @@ pub fn serialize_witness(rln_witness: &RLNWitnessInput) -> Result<Vec<u8>> {
 /// # Errors
 ///
 /// Returns an error if `message_id` is not within `user_message_limit`.
-pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)> {
+pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize), ProtocolError> {
     let mut all_read: usize = 0;
 
     let (identity_secret, read) = bytes_le_to_fr(&serialized[all_read..]);
@@ -151,7 +156,7 @@ pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)
     all_read += read;
 
     if serialized.len() != all_read {
-        return Err(Report::msg("serialized length is not equal to all_read"));
+        return Err(ProtocolError::InvalidReadLen(serialized.len(), all_read));
     }
 
     Ok((
@@ -175,15 +180,18 @@ pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)
 pub fn proof_inputs_to_rln_witness(
     tree: &mut PoseidonTree,
     serialized: &[u8],
-) -> Result<(RLNWitnessInput, usize)> {
+) -> Result<(RLNWitnessInput, usize), ProtocolError> {
     let mut all_read: usize = 0;
 
     let (identity_secret, read) = bytes_le_to_fr(&serialized[all_read..]);
     all_read += read;
 
     let id_index = usize::try_from(u64::from_le_bytes(
-        serialized[all_read..all_read + 8].try_into()?,
-    ))?;
+        serialized[all_read..all_read + 8]
+            .try_into()
+            .map_err(ConversionError::FromSlice)?,
+    ))
+    .map_err(ConversionError::ToUsize)?;
     all_read += 8;
 
     let (user_message_limit, read) = bytes_le_to_fr(&serialized[all_read..]);
@@ -196,8 +204,11 @@ pub fn proof_inputs_to_rln_witness(
     all_read += read;
 
     let signal_len = usize::try_from(u64::from_le_bytes(
-        serialized[all_read..all_read + 8].try_into()?,
-    ))?;
+        serialized[all_read..all_read + 8]
+            .try_into()
+            .map_err(ConversionError::FromSlice)?,
+    ))
+    .map_err(ConversionError::ToUsize)?;
     all_read += 8;
 
     let signal: Vec<u8> = serialized[all_read..all_read + signal_len].to_vec();
@@ -222,7 +233,7 @@ pub fn proof_inputs_to_rln_witness(
     ))
 }
 
-/// Creates `RLNWitnessInput` from it's fields.
+/// Creates [`RLNWitnessInput`] from it's fields.
 ///
 /// # Errors
 ///
@@ -234,7 +245,7 @@ pub fn rln_witness_from_values(
     external_nullifier: Fr,
     user_message_limit: Fr,
     message_id: Fr,
-) -> Result<RLNWitnessInput> {
+) -> Result<RLNWitnessInput, ProtocolError> {
     message_id_range_check(&message_id, &user_message_limit)?;
 
     let path_elements = merkle_proof.get_path_elements();
@@ -281,7 +292,9 @@ pub fn random_rln_witness(tree_height: usize) -> RLNWitnessInput {
     }
 }
 
-pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> Result<RLNProofValues> {
+pub fn proof_values_from_witness(
+    rln_witness: &RLNWitnessInput,
+) -> Result<RLNProofValues, ProtocolError> {
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
 
     // y share
@@ -309,14 +322,17 @@ 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 +369,43 @@ 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
 }
@@ -483,7 +512,7 @@ pub fn extended_seeded_keygen(signal: &[u8]) -> (Fr, Fr, Fr, Fr) {
     )
 }
 
-pub fn compute_id_secret(share1: (Fr, Fr), share2: (Fr, Fr)) -> Result<Fr, String> {
+pub fn compute_id_secret(share1: (Fr, Fr), share2: (Fr, Fr)) -> Result<Fr, ComputeIdSecretError> {
     // Assuming a0 is the identity secret and a1 = poseidonHash([a0, external_nullifier]),
     // a (x,y) share satisfies the following relation
     // y = a_0 + x * a_1
@@ -493,30 +522,25 @@ pub fn compute_id_secret(share1: (Fr, Fr), share2: (Fr, Fr)) -> Result<Fr, Strin
     // If the two input shares were computed for the same external_nullifier and identity secret, we can recover the latter
     // y1 = a_0 + x1 * a_1
     // y2 = a_0 + x2 * a_1
-    let a_1 = (y1 - y2) / (x1 - x2);
-    let a_0 = y1 - x1 * a_1;
 
-    // If shares come from the same polynomial, a0 is correctly recovered and a1 = poseidonHash([a0, external_nullifier])
-    Ok(a_0)
+    if (x1 - x2) != Fr::ZERO {
+        let a_1 = (y1 - y2) / (x1 - x2);
+        let a_0 = y1 - x1 * a_1;
+
+        // If shares come from the same polynomial, a0 is correctly recovered and a1 = poseidonHash([a0, external_nullifier])
+        Ok(a_0)
+    } else {
+        Err(ComputeIdSecretError::DivisionByZero)
+    }
 }
 
 ///////////////////////////////////////////////////////
 // zkSNARK utility functions
 ///////////////////////////////////////////////////////
 
-#[derive(Error, Debug)]
-pub enum ProofError {
-    #[error("Error reading circuit key: {0}")]
-    CircuitKeyError(#[from] Report),
-    #[error("Error producing witness: {0}")]
-    WitnessError(Report),
-    #[error("Error producing proof: {0}")]
-    SynthesisError(#[from] SynthesisError),
-}
-
 fn calculate_witness_element<E: ark_ec::pairing::Pairing>(
     witness: Vec<BigInt>,
-) -> Result<Vec<E::ScalarField>> {
+) -> Result<Vec<E::ScalarField>, ProtocolError> {
     use ark_ff::PrimeField;
     let modulus = <E::ScalarField as PrimeField>::MODULUS;
 
@@ -529,9 +553,9 @@ fn calculate_witness_element<E: ark_ec::pairing::Pairing>(
             modulus.into()
                 - w.abs()
                     .to_biguint()
-                    .ok_or(Report::msg("not a biguint value"))?
+                    .ok_or(ProtocolError::BigUintConversion(w))?
         } else {
-            w.to_biguint().ok_or(Report::msg("not a biguint value"))?
+            w.to_biguint().ok_or(ProtocolError::BigUintConversion(w))?
         };
         witness_vec.push(E::ScalarField::from(w))
     }
@@ -544,13 +568,12 @@ 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)?;
+    let full_assignment = calculate_witness_element::<Curve>(witness)?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("witness generation took: {:.2?}", now.elapsed());
 
     // Random Values
@@ -559,7 +582,7 @@ 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 +595,7 @@ 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 +608,23 @@ 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], ProtocolError> {
     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 +634,20 @@ 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 +656,7 @@ 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 +668,7 @@ pub fn generate_proof(
         full_assignment.as_slice(),
     )?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("proof generation took: {:.2?}", now.elapsed());
 
     Ok(proof)
@@ -707,12 +699,12 @@ 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)
@@ -739,43 +731,49 @@ where
     a.map_err(serde::de::Error::custom)
 }
 
-/// Converts a JSON value into [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object.
+/// Converts a JSON value into [`RLNWitnessInput`] object.
 ///
 /// # Errors
 ///
 /// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
-pub fn rln_witness_from_json(input_json: serde_json::Value) -> Result<RLNWitnessInput> {
+pub fn rln_witness_from_json(
+    input_json: serde_json::Value,
+) -> Result<RLNWitnessInput, ProtocolError> {
     let rln_witness: RLNWitnessInput = serde_json::from_value(input_json).unwrap();
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
 
     Ok(rln_witness)
 }
 
-/// Converts a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object to the corresponding JSON serialization.
+/// Converts a [`RLNWitnessInput`] object to the corresponding JSON serialization.
 ///
 /// # Errors
 ///
 /// Returns an error if `message_id` is not within `user_message_limit`.
-pub fn rln_witness_to_json(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
+pub fn rln_witness_to_json(
+    rln_witness: &RLNWitnessInput,
+) -> Result<serde_json::Value, ProtocolError> {
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
 
     let rln_witness_json = serde_json::to_value(rln_witness)?;
     Ok(rln_witness_json)
 }
 
-/// Converts a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object to the corresponding JSON serialization.
+/// 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> {
+pub fn rln_witness_to_bigint_json(
+    rln_witness: &RLNWitnessInput,
+) -> Result<serde_json::Value, ProtocolError> {
     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));
+        path_elements.push(to_bigint(v).to_str_radix(10));
     }
 
     let mut identity_path_index = Vec::new();
@@ -785,22 +783,26 @@ pub fn rln_witness_to_bigint_json(rln_witness: &RLNWitnessInput) -> Result<serde
         .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),
+        "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),
+        "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<()> {
+pub fn message_id_range_check(
+    message_id: &Fr,
+    user_message_limit: &Fr,
+) -> Result<(), ProtocolError> {
     if message_id > user_message_limit {
-        return Err(color_eyre::Report::msg(
-            "message_id is not within user_message_limit",
+        return Err(ProtocolError::InvalidMessageId(
+            *message_id,
+            *user_message_limit,
         ));
     }
     Ok(())

rln/src/public.rs

@@ -1,34 +1,42 @@
-use crate::circuit::{vk_from_raw, zkey_from_raw, Curve, Fr};
+use crate::circuit::{zkey_from_raw, Curve, Fr};
 use crate::hashers::{hash_to_field, poseidon_hash as utils_poseidon_hash};
-use crate::protocol::*;
-use crate::utils::*;
+use crate::protocol::{
+    compute_id_secret, deserialize_proof_values, deserialize_witness, extended_keygen,
+    extended_seeded_keygen, generate_proof, keygen, proof_inputs_to_rln_witness,
+    proof_values_from_witness, rln_witness_to_bigint_json, rln_witness_to_json, seeded_keygen,
+    serialize_proof_values, serialize_witness, verify_proof,
+};
+use crate::utils::{
+    bytes_le_to_fr, bytes_le_to_vec_fr, bytes_le_to_vec_u8, fr_byte_size, fr_to_bytes_le,
+    vec_fr_to_bytes_le, vec_u8_to_bytes_le,
+};
+#[cfg(not(target_arch = "wasm32"))]
+use {
+    crate::circuit::{graph_from_folder, zkey_from_folder},
+    std::default::Default,
+};
+
+#[cfg(target_arch = "wasm32")]
+use crate::protocol::generate_proof_with_witness;
+
 /// 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};
+#[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::error::{ConversionError, ProtocolError, RLNError};
+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};
+#[cfg(target_arch = "wasm32")]
+use num_bigint::BigInt;
 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 crate::poseidon_tree::PoseidonTree;
-        use serde_json::{json, Value};
-        use utils::{Hasher};
-        use std::sync::Arc;
-        use std::str::FromStr;
-    } else {
-        use std::marker::*;
-        use num_bigint::BigInt;
-    }
-}
+use utils::error::ZerokitMerkleTreeError;
 
 /// The application-specific RLN identifier.
 ///
@@ -43,16 +51,10 @@ pub const RLN_IDENTIFIER: &[u8] = b"zerokit/rln/010203040506070809";
 pub struct RLN {
     proving_key: (ProvingKey<Curve>, ConstraintMatrices<Fr>),
     pub(crate) verification_key: VerifyingKey<Curve>,
+    #[cfg(not(target_arch = "wasm32"))]
+    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: Arc<Mutex<WitnessCalculator>>,
-    #[cfg(target_arch = "wasm32")]
-    _marker: PhantomData<()>,
 }
 
 impl RLN {
@@ -73,7 +75,7 @@ impl RLN {
     /// let mut rln = RLN::new(tree_height, input);
     /// ```
     #[cfg(all(not(target_arch = "wasm32"), not(feature = "stateless")))]
-    pub fn new<R: Read>(tree_height: usize, mut input_data: R) -> Result<RLN> {
+    pub fn new<R: Read>(tree_height: usize, mut input_data: R) -> Result<RLN, RLNError> {
         // We read input
         let mut input: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut input)?;
@@ -81,10 +83,9 @@ 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().to_owned();
+        let verification_key = proving_key.0.vk.to_owned();
+        let graph_data = graph_from_folder().to_owned();
 
         let tree_config: <PoseidonTree as ZerokitMerkleTree>::Config = if tree_config.is_empty() {
             <PoseidonTree as ZerokitMerkleTree>::Config::default()
@@ -100,13 +101,11 @@ impl RLN {
         )?;
 
         Ok(RLN {
-            witness_calculator: witness_calculator.to_owned(),
-            proving_key: proving_key.to_owned(),
-            verification_key: verification_key.to_owned(),
+            proving_key,
+            verification_key,
+            graph_data,
             #[cfg(not(feature = "stateless"))]
             tree,
-            #[cfg(target_arch = "wasm32")]
-            _marker: PhantomData,
         })
     }
 
@@ -118,20 +117,16 @@ impl RLN {
     /// // We create a new RLN instance
     /// let mut rln = RLN::new();
     /// ```
-    #[cfg_attr(docsrs, doc(cfg(feature = "stateless")))]
     #[cfg(all(not(target_arch = "wasm32"), feature = "stateless"))]
-    pub fn new() -> Result<RLN> {
-        #[cfg(not(target_arch = "wasm32"))]
-        let witness_calculator = circom_from_folder();
-        let proving_key = zkey_from_folder();
-        let verification_key = vk_from_folder();
+    pub fn new() -> Result<RLN, RLNError> {
+        let proving_key = zkey_from_folder().to_owned();
+        let verification_key = proving_key.0.vk.to_owned();
+        let graph_data = graph_from_folder().to_owned();
 
         Ok(RLN {
-            witness_calculator: witness_calculator.to_owned(),
-            proving_key: proving_key.to_owned(),
-            verification_key: verification_key.to_owned(),
-            #[cfg(target_arch = "wasm32")]
-            _marker: PhantomData,
+            proving_key,
+            verification_key,
+            graph_data,
         })
     }
 
@@ -139,9 +134,8 @@ 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.arkvkey`) as binary file
+    /// - `graph_data`: a byte vector containing the graph data (`graph.bin`) as binary file
     /// - `tree_config_input`: a reader for a string containing a json with the merkle tree configuration
     ///
     /// Example:
@@ -153,38 +147,34 @@ 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.arkvkey"] {
+    /// 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(all(not(target_arch = "wasm32"), 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> {
-        #[cfg(not(target_arch = "wasm32"))]
-        let witness_calculator = circom_from_raw(&circom_vec)?;
-
+    ) -> Result<RLN, RLNError> {
         let proving_key = zkey_from_raw(&zkey_vec)?;
-        let verification_key = vk_from_raw(&vk_vec, &zkey_vec)?;
+        let verification_key = proving_key.0.vk.to_owned();
 
         let mut tree_config_vec: Vec<u8> = Vec::new();
         tree_config_input.read_to_end(&mut tree_config_vec)?;
@@ -204,22 +194,19 @@ impl RLN {
         )?;
 
         Ok(RLN {
-            witness_calculator,
             proving_key,
             verification_key,
+            graph_data,
             #[cfg(not(feature = "stateless"))]
             tree,
-            #[cfg(target_arch = "wasm32")]
-            _marker: PhantomData,
         })
     }
 
     /// Creates a new stateless RLN object by passing circuit resources as byte vectors.
     ///
     /// Input parameters are
-    /// - `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.arkvkey`) as binary file
+    /// - `graph_data`: a byte vector containing the graph data (`graph.bin`) as binary file
     ///
     /// Example:
     /// ```
@@ -229,7 +216,7 @@ 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.arkvkey"] {
+    /// 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");
@@ -241,60 +228,47 @@ impl RLN {
     /// let mut rln = RLN::new_with_params(
     ///     resources[0].clone(),
     ///     resources[1].clone(),
-    ///     resources[2].clone(),
     /// );
     /// ```
     #[cfg(all(not(target_arch = "wasm32"), feature = "stateless"))]
-    pub fn new_with_params(circom_vec: Vec<u8>, zkey_vec: Vec<u8>, vk_vec: Vec<u8>) -> Result<RLN> {
-        let witness_calculator = circom_from_raw(&circom_vec)?;
-
+    pub fn new_with_params(zkey_vec: Vec<u8>, graph_data: Vec<u8>) -> Result<RLN, RLNError> {
         let proving_key = zkey_from_raw(&zkey_vec)?;
-        let verification_key = vk_from_raw(&vk_vec, &zkey_vec)?;
+        let verification_key = proving_key.0.vk.to_owned();
 
         Ok(RLN {
-            witness_calculator,
             proving_key,
             verification_key,
+            graph_data,
         })
     }
 
-    /// Creates a new stateless RLN object by passing circuit resources as byte vectors.
+    /// Creates a new stateless RLN object by passing circuit resources as a byte vector.
     ///
     /// Input parameters are
-    /// - `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.arkvkey`) as binary file
+    /// - `zkey_vec`: a byte vector containing 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 zkey_path = "./resources/tree_height_20/rln_final.zkey";
     ///
-    /// let mut resources: Vec<Vec<u8>> = Vec::new();
-    /// for filename in ["rln_final.zkey", "verification_key.arkvkey"] {
-    ///     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 file = File::open(zkey_path).expect("Failed to open file");
+    /// let metadata = std::fs::metadata(zkey_path).expect("Failed to read metadata");
+    /// let mut zkey_vec = vec![0; metadata.len() as usize];
+    /// file.read_exact(&mut zkey_vec).expect("Failed to read file");
     ///
-    /// let mut rln = RLN::new_with_params(
-    ///     resources[0].clone(),
-    ///     resources[1].clone(),
-    /// );
+    /// let mut rln = RLN::new_with_params(zkey_vec)?;
     /// ```
     #[cfg(all(target_arch = "wasm32", feature = "stateless"))]
-    pub fn new_with_params(zkey_vec: Vec<u8>, vk_vec: Vec<u8>) -> Result<RLN> {
+    pub fn new_with_params(zkey_vec: Vec<u8>) -> Result<RLN, RLNError> {
         let proving_key = zkey_from_raw(&zkey_vec)?;
-        let verification_key = vk_from_raw(&vk_vec, &zkey_vec)?;
+        let verification_key = proving_key.0.vk.to_owned();
 
         Ok(RLN {
             proving_key,
             verification_key,
-            _marker: PhantomData,
         })
     }
 
@@ -308,7 +282,7 @@ 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<()> {
+    pub fn set_tree(&mut self, tree_height: usize) -> Result<(), RLNError> {
         // We compute a default empty tree of desired height
         self.tree = PoseidonTree::default(tree_height)?;
 
@@ -339,7 +313,7 @@ impl RLN {
     /// 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<()> {
+    pub fn set_leaf<R: Read>(&mut self, index: usize, mut input_data: R) -> Result<(), RLNError> {
         // We read input
         let mut leaf_byte: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut leaf_byte)?;
@@ -369,7 +343,7 @@ impl RLN {
     /// 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<()> {
+    pub fn get_leaf<W: Write>(&self, index: usize, mut output_data: W) -> Result<(), RLNError> {
         // We get the leaf at input index
         let leaf = self.tree.get(index)?;
 
@@ -412,7 +386,11 @@ impl RLN {
     /// 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<()> {
+    pub fn set_leaves_from<R: Read>(
+        &mut self,
+        index: usize,
+        mut input_data: R,
+    ) -> Result<(), RLNError> {
         // We read input
         let mut leaves_byte: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut leaves_byte)?;
@@ -421,8 +399,7 @@ impl RLN {
 
         // We set the leaves
         self.tree
-            .override_range(index, leaves, [])
-            .map_err(|_| Report::msg("Could not set leaves"))?;
+            .override_range(index, leaves.into_iter(), [].into_iter())?;
         Ok(())
     }
 
@@ -433,7 +410,7 @@ 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<()> {
+    pub fn init_tree_with_leaves<R: Read>(&mut self, input_data: R) -> Result<(), RLNError> {
         // reset the tree
         // NOTE: this requires the tree to be initialized with the correct height initially
         // TODO: accept tree_height as a parameter and initialize the tree with that height
@@ -489,7 +466,7 @@ impl RLN {
         index: usize,
         mut input_leaves: R,
         mut input_indices: R,
-    ) -> Result<()> {
+    ) -> Result<(), RLNError> {
         // We read input
         let mut leaves_byte: Vec<u8> = Vec::new();
         input_leaves.read_to_end(&mut leaves_byte)?;
@@ -504,8 +481,7 @@ impl RLN {
 
         // We set the leaves
         self.tree
-            .override_range(index, leaves, indices)
-            .map_err(|e| Report::msg(format!("Could not perform the batch operation: {e}")))?;
+            .override_range(index, leaves.into_iter(), indices.into_iter())?;
         Ok(())
     }
 
@@ -558,7 +534,7 @@ impl RLN {
     /// 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<()> {
+    pub fn set_next_leaf<R: Read>(&mut self, mut input_data: R) -> Result<(), RLNError> {
         // We read input
         let mut leaf_byte: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut leaf_byte)?;
@@ -584,7 +560,7 @@ impl RLN {
     /// rln.delete_leaf(index).unwrap();
     /// ```
     #[cfg(not(feature = "stateless"))]
-    pub fn delete_leaf(&mut self, index: usize) -> Result<()> {
+    pub fn delete_leaf(&mut self, index: usize) -> Result<(), RLNError> {
         self.tree.delete(index)?;
         Ok(())
     }
@@ -602,7 +578,7 @@ impl RLN {
     /// rln.set_metadata(metadata).unwrap();
     /// ```
     #[cfg(not(feature = "stateless"))]
-    pub fn set_metadata(&mut self, metadata: &[u8]) -> Result<()> {
+    pub fn set_metadata(&mut self, metadata: &[u8]) -> Result<(), RLNError> {
         self.tree.set_metadata(metadata)?;
         Ok(())
     }
@@ -622,7 +598,7 @@ impl RLN {
     /// let metadata = buffer.into_inner();
     /// ```
     #[cfg(not(feature = "stateless"))]
-    pub fn get_metadata<W: Write>(&self, mut output_data: W) -> Result<()> {
+    pub fn get_metadata<W: Write>(&self, mut output_data: W) -> Result<(), RLNError> {
         let metadata = self.tree.metadata()?;
         output_data.write_all(&metadata)?;
         Ok(())
@@ -642,10 +618,9 @@ impl RLN {
     /// 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<()> {
+    pub fn get_root<W: Write>(&self, mut output_data: W) -> Result<(), RLNError> {
         let root = self.tree.root();
         output_data.write_all(&fr_to_bytes_le(&root))?;
-
         Ok(())
     }
 
@@ -670,7 +645,7 @@ impl RLN {
         level: usize,
         index: usize,
         mut output_data: W,
-    ) -> Result<()> {
+    ) -> Result<(), RLNError> {
         let subroot = self.tree.get_subtree_root(level, index)?;
         output_data.write_all(&fr_to_bytes_le(&subroot))?;
 
@@ -699,13 +674,14 @@ impl RLN {
     /// 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<()> {
+    pub fn get_proof<W: Write>(&self, index: usize, mut output_data: W) -> Result<(), RLNError> {
         let merkle_proof = self.tree.proof(index).expect("proof should exist");
         let path_elements = merkle_proof.get_path_elements();
         let identity_path_index = merkle_proof.get_path_index();
 
-        output_data.write_all(&vec_fr_to_bytes_le(&path_elements)?)?;
-        output_data.write_all(&vec_u8_to_bytes_le(&identity_path_index)?)?;
+        // Note: unwrap safe - vec_fr_to_bytes_le & vec_u8_to_bytes_le are infallible
+        output_data.write_all(&vec_fr_to_bytes_le(&path_elements))?;
+        output_data.write_all(&vec_u8_to_bytes_le(&identity_path_index))?;
 
         Ok(())
     }
@@ -743,7 +719,7 @@ impl RLN {
     /// 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<()> {
+    pub fn get_empty_leaves_indices<W: Write>(&self, mut output_data: W) -> Result<(), RLNError> {
         let idxs = self.tree.get_empty_leaves_indices();
         idxs.serialize_compressed(&mut output_data)?;
         Ok(())
@@ -752,10 +728,10 @@ 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
@@ -778,19 +754,13 @@ impl RLN {
         &mut self,
         mut input_data: R,
         mut output_data: W,
-    ) -> Result<()> {
+    ) -> Result<(), RLNError> {
         // We read input RLN witness and we serialize_compressed it
-        let mut serialized: Vec<u8> = Vec::new();
-        input_data.read_to_end(&mut serialized)?;
-        let (rln_witness, _) = deserialize_witness(&serialized)?;
+        let mut serialized_witness: Vec<u8> = Vec::new();
+        input_data.read_to_end(&mut serialized_witness)?;
+        let (rln_witness, _) = deserialize_witness(&serialized_witness)?;
 
-        /*
-        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)?;
@@ -834,7 +804,7 @@ impl RLN {
     ///
     /// assert!(verified);
     /// ```
-    pub fn verify<R: Read>(&self, mut input_data: R) -> Result<bool> {
+    pub fn verify<R: Read>(&self, mut input_data: R) -> Result<bool, RLNError> {
         // Input data is serialized for Curve as:
         // serialized_proof (compressed, 4*32 bytes) || serialized_proof_values (6*32 bytes), i.e.
         // [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
@@ -872,26 +842,25 @@ 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());
@@ -906,14 +875,14 @@ impl RLN {
         &mut self,
         mut input_data: R,
         mut output_data: W,
-    ) -> Result<()> {
+    ) -> Result<(), RLNError> {
         // We read input RLN witness and we serialize_compressed it
         let mut witness_byte: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut witness_byte)?;
         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
@@ -923,45 +892,43 @@ 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
+    /// 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(not(target_arch = "wasm32"))]
     pub fn generate_rln_proof_with_witness<R: Read, W: Write>(
         &mut self,
         mut input_data: R,
         mut output_data: W,
-    ) -> Result<()> {
-        let mut witness_byte: Vec<u8> = Vec::new();
-        input_data.read_to_end(&mut witness_byte)?;
-        let (rln_witness, _) = deserialize_witness(&witness_byte)?;
+    ) -> Result<(), RLNError> {
+        let mut serialized_witness: Vec<u8> = Vec::new();
+        input_data.read_to_end(&mut serialized_witness)?;
+        let (rln_witness, _) = deserialize_witness(&serialized_witness)?;
         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
+        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>]
+    #[cfg(target_arch = "wasm32")]
+    pub fn generate_rln_proof_with_witness<W: Write>(
+        &mut self,
+        calculated_witness: Vec<BigInt>,
+        serialized_witness: Vec<u8>,
+        mut output_data: W,
+    ) -> Result<(), RLNError> {
+        let (rln_witness, _) = deserialize_witness(&serialized_witness[..])?;
+        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
@@ -990,16 +957,15 @@ 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> {
+    pub fn verify_rln_proof<R: Read>(&self, mut input_data: R) -> Result<bool, RLNError> {
         let mut serialized: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut serialized)?;
         let mut all_read = 0;
@@ -1010,8 +976,11 @@ impl RLN {
         all_read += read;
 
         let signal_len = usize::try_from(u64::from_le_bytes(
-            serialized[all_read..all_read + 8].try_into()?,
-        ))?;
+            serialized[all_read..all_read + 8]
+                .try_into()
+                .map_err(ConversionError::FromSlice)?,
+        ))
+        .map_err(ConversionError::from)?;
         all_read += 8;
 
         let signal: Vec<u8> = serialized[all_read..all_read + signal_len].to_vec();
@@ -1069,12 +1038,16 @@ 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);
     /// ```
-    pub fn verify_with_roots<R: Read>(&self, mut input_data: R, mut roots_data: R) -> Result<bool> {
+    pub fn verify_with_roots<R: Read>(
+        &self,
+        mut input_data: R,
+        mut roots_data: R,
+    ) -> Result<bool, RLNError> {
         let mut serialized: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut serialized)?;
         let mut all_read = 0;
@@ -1085,8 +1058,11 @@ impl RLN {
         all_read += read;
 
         let signal_len = usize::try_from(u64::from_le_bytes(
-            serialized[all_read..all_read + 8].try_into()?,
-        ))?;
+            serialized[all_read..all_read + 8]
+                .try_into()
+                .map_err(ConversionError::FromSlice)?,
+        ))
+        .map_err(ConversionError::ToUsize)?;
         all_read += 8;
 
         let signal: Vec<u8> = serialized[all_read..all_read + signal_len].to_vec();
@@ -1155,7 +1131,7 @@ impl RLN {
     /// // We serialize_compressed the keygen output
     /// let (identity_secret_hash, id_commitment) = deserialize_identity_pair(buffer.into_inner());
     /// ```
-    pub fn key_gen<W: Write>(&self, mut output_data: W) -> Result<()> {
+    pub fn key_gen<W: Write>(&self, mut output_data: W) -> Result<(), RLNError> {
         let (identity_secret_hash, id_commitment) = keygen();
         output_data.write_all(&fr_to_bytes_le(&identity_secret_hash))?;
         output_data.write_all(&fr_to_bytes_le(&id_commitment))?;
@@ -1185,7 +1161,7 @@ impl RLN {
     /// // We serialize_compressed the keygen output
     /// let (identity_trapdoor, identity_nullifier, identity_secret_hash, id_commitment) = deserialize_identity_tuple(buffer.into_inner());
     /// ```
-    pub fn extended_key_gen<W: Write>(&self, mut output_data: W) -> Result<()> {
+    pub fn extended_key_gen<W: Write>(&self, mut output_data: W) -> Result<(), RLNError> {
         let (identity_trapdoor, identity_nullifier, identity_secret_hash, id_commitment) =
             extended_keygen();
         output_data.write_all(&fr_to_bytes_le(&identity_trapdoor))?;
@@ -1224,7 +1200,7 @@ impl RLN {
         &self,
         mut input_data: R,
         mut output_data: W,
-    ) -> Result<()> {
+    ) -> Result<(), RLNError> {
         let mut serialized: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut serialized)?;
 
@@ -1267,7 +1243,7 @@ impl RLN {
         &self,
         mut input_data: R,
         mut output_data: W,
-    ) -> Result<()> {
+    ) -> Result<(), RLNError> {
         let mut serialized: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut serialized)?;
 
@@ -1320,7 +1296,7 @@ impl RLN {
         mut input_proof_data_1: R,
         mut input_proof_data_2: R,
         mut output_data: W,
-    ) -> Result<()> {
+    ) -> Result<(), RLNError> {
         // 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)?;
@@ -1344,57 +1320,60 @@ impl RLN {
             let share2 = (proof_values_2.x, proof_values_2.y);
 
             // We recover the secret
-            let recovered_identity_secret_hash = compute_id_secret(share1, share2);
+            let recovered_identity_secret_hash =
+                compute_id_secret(share1, share2).map_err(RLNError::RecoverSecret)?;
 
             // If an identity secret hash is recovered, we write it to output_data, otherwise nothing will be written.
-            if let Ok(identity_secret_hash) = recovered_identity_secret_hash {
-                output_data.write_all(&fr_to_bytes_le(&identity_secret_hash))?;
-            } else {
-                return Err(Report::msg("could not extract secret"));
-            }
+            output_data.write_all(&fr_to_bytes_le(&recovered_identity_secret_hash))?;
         }
 
         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>> {
+    pub fn get_serialized_rln_witness<R: Read>(
+        &mut self,
+        mut input_data: R,
+    ) -> Result<Vec<u8>, RLNError> {
         // We read input RLN witness and we serialize_compressed it
         let mut witness_byte: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut witness_byte)?;
         let (rln_witness, _) = proof_inputs_to_rln_witness(&mut self.tree, &witness_byte)?;
 
-        serialize_witness(&rln_witness)
+        serialize_witness(&rln_witness).map_err(RLNError::Protocol)
     }
 
-    /// 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.
-    pub fn get_rln_witness_json(&mut self, serialized_witness: &[u8]) -> Result<serde_json::Value> {
+    /// 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, ProtocolError> {
         let (rln_witness, _) = deserialize_witness(serialized_witness)?;
         rln_witness_to_json(&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.
     /// 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`](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_bigint_json(
         &mut self,
         serialized_witness: &[u8],
-    ) -> Result<serde_json::Value> {
+    ) -> Result<serde_json::Value, ProtocolError> {
         let (rln_witness, _) = deserialize_witness(serialized_witness)?;
         rln_witness_to_bigint_json(&rln_witness)
     }
@@ -1404,7 +1383,7 @@ impl RLN {
     /// 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<()> {
+    pub fn flush(&mut self) -> Result<(), ZerokitMerkleTreeError> {
         self.tree.close_db_connection()
     }
 }
@@ -1445,7 +1424,10 @@ impl Default for RLN {
 /// // We serialize_compressed the keygen output
 /// let field_element = deserialize_field_element(output_buffer.into_inner());
 /// ```
-pub fn hash<R: Read, W: Write>(mut input_data: R, mut output_data: W) -> Result<()> {
+pub fn hash<R: Read, W: Write>(
+    mut input_data: R,
+    mut output_data: W,
+) -> Result<(), std::io::Error> {
     let mut serialized: Vec<u8> = Vec::new();
     input_data.read_to_end(&mut serialized)?;
 
@@ -1478,7 +1460,10 @@ pub fn hash<R: Read, W: Write>(mut input_data: R, mut output_data: W) -> Result<
 /// // We serialize_compressed the hash output
 /// let hash_result = deserialize_field_element(output_buffer.into_inner());
 /// ```
-pub fn poseidon_hash<R: Read, W: Write>(mut input_data: R, mut output_data: W) -> Result<()> {
+pub fn poseidon_hash<R: Read, W: Write>(
+    mut input_data: R,
+    mut output_data: W,
+) -> Result<(), RLNError> {
     let mut serialized: Vec<u8> = Vec::new();
     input_data.read_to_end(&mut serialized)?;
 

rln/src/public_api_tests.rs

@@ -1,7 +1,10 @@
 use crate::circuit::TEST_TREE_HEIGHT;
-use crate::protocol::*;
+use crate::protocol::{
+    proof_values_from_witness, random_rln_witness, serialize_proof_values, serialize_witness,
+    verify_proof, RLNProofValues,
+};
 use crate::public::RLN;
-use crate::utils::*;
+use crate::utils::{generate_input_buffer, str_to_fr};
 use ark_groth16::Proof as ArkProof;
 use ark_serialize::CanonicalDeserialize;
 use std::io::Cursor;
@@ -9,28 +12,28 @@ use std::str::FromStr;
 
 use serde_json::{json, Value};
 
-fn fq_from_str(s: String) -> ark_bn254::Fq {
+fn fq_from_str(s: &str) -> ark_bn254::Fq {
     ark_bn254::Fq::from_str(&s).unwrap()
 }
 
 fn g1_from_str(g1: &[String]) -> ark_bn254::G1Affine {
-    let x = fq_from_str(g1[0].clone());
-    let y = fq_from_str(g1[1].clone());
-    let z = fq_from_str(g1[2].clone());
+    let x = fq_from_str(&g1[0]);
+    let y = fq_from_str(&g1[1]);
+    let z = fq_from_str(&g1[2]);
     ark_bn254::G1Affine::from(ark_bn254::G1Projective::new(x, y, z))
 }
 
 fn g2_from_str(g2: &[Vec<String>]) -> ark_bn254::G2Affine {
-    let c0 = fq_from_str(g2[0][0].clone());
-    let c1 = fq_from_str(g2[0][1].clone());
+    let c0 = fq_from_str(&g2[0][0]);
+    let c1 = fq_from_str(&g2[0][1]);
     let x = ark_bn254::Fq2::new(c0, c1);
 
-    let c0 = fq_from_str(g2[1][0].clone());
-    let c1 = fq_from_str(g2[1][1].clone());
+    let c0 = fq_from_str(&g2[1][0]);
+    let c1 = fq_from_str(&g2[1][1]);
     let y = ark_bn254::Fq2::new(c0, c1);
 
-    let c0 = fq_from_str(g2[2][0].clone());
-    let c1 = fq_from_str(g2[2][1].clone());
+    let c0 = fq_from_str(&g2[2][0]);
+    let c1 = fq_from_str(&g2[2][1]);
     let z = ark_bn254::Fq2::new(c0, c1);
 
     ark_bn254::G2Affine::from(ark_bn254::G2Projective::new(x, y, z))
@@ -231,7 +234,7 @@ mod tree_test {
         rln.set_tree(tree_height).unwrap();
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // We check if number of leaves set is consistent
@@ -289,7 +292,7 @@ mod tree_test {
         let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // We check if number of leaves set is consistent
@@ -303,11 +306,11 @@ mod tree_test {
         // `init_tree_with_leaves` resets the tree to the height it was initialized with, using `set_tree`
 
         // We add leaves in a batch starting from index 0..set_index
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves[0..set_index]).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves[0..set_index]));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // We add the remaining n leaves in a batch starting from index m
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves[set_index..]).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves[set_index..]));
         rln.set_leaves_from(set_index, &mut buffer).unwrap();
 
         // We check if number of leaves set is consistent
@@ -359,7 +362,7 @@ mod tree_test {
         let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // We check if number of leaves set is consistent
@@ -377,8 +380,8 @@ mod tree_test {
         let last_leaf_index = no_of_leaves - 1;
         let indices = vec![last_leaf_index as u8];
         let last_leaf = vec![*last_leaf];
-        let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices).unwrap());
-        let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&last_leaf).unwrap());
+        let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices));
+        let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&last_leaf));
 
         rln.atomic_operation(last_leaf_index, leaves_buffer, indices_buffer)
             .unwrap();
@@ -408,7 +411,7 @@ mod tree_test {
         let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // We check if number of leaves set is consistent
@@ -422,8 +425,8 @@ mod tree_test {
         let zero_index = 0;
         let indices = vec![zero_index as u8];
         let zero_leaf: Vec<Fr> = vec![];
-        let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices).unwrap());
-        let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&zero_leaf).unwrap());
+        let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices));
+        let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&zero_leaf));
         rln.atomic_operation(0, leaves_buffer, indices_buffer)
             .unwrap();
 
@@ -452,7 +455,7 @@ mod tree_test {
         let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // We check if number of leaves set is consistent
@@ -466,8 +469,8 @@ mod tree_test {
         let set_index = rng.gen_range(0..no_of_leaves) as usize;
         let indices = vec![set_index as u8];
         let zero_leaf: Vec<Fr> = vec![];
-        let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices).unwrap());
-        let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&zero_leaf).unwrap());
+        let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices));
+        let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&zero_leaf));
         rln.atomic_operation(0, leaves_buffer, indices_buffer)
             .unwrap();
 
@@ -486,7 +489,6 @@ mod tree_test {
         assert_eq!(received_leaf, Fr::from(0));
     }
 
-    #[allow(unused_must_use)]
     #[test]
     // This test checks if `set_leaves_from` throws an error when the index is out of bounds
     fn test_set_leaves_bad_index() {
@@ -510,7 +512,9 @@ mod tree_test {
         let (root_empty, _) = bytes_le_to_fr(&buffer.into_inner());
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
+
+        #[allow(unused_must_use)]
         rln.set_leaves_from(bad_index, &mut buffer)
             .expect_err("Should throw an error");
 
@@ -598,7 +602,7 @@ mod tree_test {
         let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // Generate identity pair
@@ -619,35 +623,36 @@ mod tree_test {
         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
-        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)));
-        serialized.append(&mut fr_to_bytes_le(&utils_poseidon_hash(&[
-            epoch,
-            rln_identifier,
-        ])));
-        serialized.append(&mut normalize_usize(signal.len()));
-        serialized.append(&mut signal.to_vec());
+        // 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_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 input_buffer = Cursor::new(prove_input);
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
         rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
             .unwrap();
 
         // output_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let mut proof_data = output_buffer.into_inner();
+        let proof_data = output_buffer.into_inner();
 
         // 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> ]
+        // 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);
@@ -669,7 +674,7 @@ mod tree_test {
         let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // Generate identity pair
@@ -690,22 +695,23 @@ mod tree_test {
         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 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)));
-        serialized.append(&mut fr_to_bytes_le(&utils_poseidon_hash(&[
-            epoch,
-            rln_identifier,
-        ])));
-        serialized.append(&mut normalize_usize(signal.len()));
-        serialized.append(&mut signal.to_vec());
+        // 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_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 input_buffer = Cursor::new(prove_input);
 
         // We read input RLN witness and we serialize_compressed it
         let mut witness_byte: Vec<u8> = Vec::new();
@@ -720,16 +726,15 @@ mod tree_test {
         rln.generate_rln_proof_with_witness(&mut input_buffer, &mut output_buffer)
             .unwrap();
 
-        // output_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let mut proof_data = output_buffer.into_inner();
+        // output_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+        let proof_data = output_buffer.into_inner();
 
         // 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> ]
+        // 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);
@@ -752,7 +757,7 @@ mod tree_test {
         let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
 
         // We add leaves in a batch into the tree
-        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+        let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
         rln.init_tree_with_leaves(&mut buffer).unwrap();
 
         // Generate identity pair
@@ -773,33 +778,35 @@ mod tree_test {
         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> | 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(identity_index));
-        serialized.append(&mut fr_to_bytes_le(&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());
+        // 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_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 input_buffer = Cursor::new(prove_input);
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
         rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
             .unwrap();
 
-        // output_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let mut proof_data = output_buffer.into_inner();
+        // output_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+        let proof_data = output_buffer.into_inner();
 
-        // 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> ]
+        // input_data is  [ proof<128> |// We prepare input for verify_rln_proof API 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 input_buffer = Cursor::new(proof_data);
+        let verify_input = prepare_verify_input(proof_data, &signal);
+
+        let mut input_buffer = Cursor::new(verify_input);
 
         // 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_serialized: Vec<u8> = Vec::new();
@@ -828,9 +835,9 @@ mod tree_test {
 
         // We add the real root and we check if now the proof is verified
         roots_serialized.append(&mut fr_to_bytes_le(&root));
-        roots_buffer = Cursor::new(roots_serialized.clone());
+        roots_buffer = Cursor::new(roots_serialized);
         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);
@@ -846,7 +853,6 @@ mod tree_test {
         // Generate identity pair
         let (identity_secret_hash, id_commitment) = keygen();
         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 id_commitment after storing its index
@@ -864,41 +870,49 @@ mod tree_test {
         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 generate two proofs using same epoch but different signals.
 
         // We prepare input for generate_rln_proof API
-        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 second 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 generate the first proof
-        let mut input_buffer = Cursor::new(serialized1);
+        let mut input_buffer = Cursor::new(prove_input1);
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
         rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
             .unwrap();
+
+        // output_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
         let proof_data_1 = output_buffer.into_inner();
 
         // We generate the second proof
-        let mut input_buffer = Cursor::new(serialized2);
+        let mut input_buffer = Cursor::new(prove_input2);
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
         rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
             .unwrap();
+
+        // output_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
         let proof_data_2 = output_buffer.into_inner();
 
         let mut input_proof_data_1 = Cursor::new(proof_data_1.clone());
@@ -935,25 +949,24 @@ mod tree_test {
         let signal3: [u8; 32] = rng.gen();
 
         // We prepare proof input. Note that epoch is the same as before
-        let mut serialized3: Vec<u8> = Vec::new();
-        serialized3.append(&mut fr_to_bytes_le(&identity_secret_hash_new));
-        serialized3.append(&mut normalize_usize(identity_index_new));
-        serialized3.append(&mut fr_to_bytes_le(&user_message_limit));
-        serialized3.append(&mut fr_to_bytes_le(&message_id));
-        serialized3.append(&mut fr_to_bytes_le(&external_nullifier));
-        serialized3.append(&mut normalize_usize(signal3.len()));
-        serialized3.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 generate the proof
-        let mut input_buffer = Cursor::new(serialized3);
+        let mut input_buffer = Cursor::new(prove_input3);
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
         rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
             .unwrap();
         let proof_data_3 = output_buffer.into_inner();
 
         // We attempt to recover the secret using share1 (coming from identity_secret_hash) and share3 (coming from identity_secret_hash_new)
-
-        let mut input_proof_data_1 = Cursor::new(proof_data_1.clone());
+        let mut input_proof_data_1 = Cursor::new(proof_data_1);
         let mut input_proof_data_3 = Cursor::new(proof_data_3);
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
         rln.recover_id_secret(
@@ -1022,7 +1035,7 @@ mod stateless_test {
         let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
 
         // We 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> ]
+        // 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 x = hash_to_field(&signal);
         let merkle_proof = tree.proof(identity_index).expect("proof should exist");
@@ -1043,15 +1056,15 @@ mod stateless_test {
         rln.generate_rln_proof_with_witness(&mut input_buffer, &mut output_buffer)
             .unwrap();
 
-        // output_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
-        let mut proof_data = output_buffer.into_inner();
+        // output_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+        let proof_data = output_buffer.into_inner();
 
         // 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 input_buffer = Cursor::new(proof_data);
+        let verify_input = prepare_verify_input(proof_data, &signal);
+
+        let mut input_buffer = Cursor::new(verify_input);
 
         // 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_serialized: Vec<u8> = Vec::new();
@@ -1078,9 +1091,9 @@ mod stateless_test {
 
         // We add the real root and we check if now the proof is verified
         roots_serialized.append(&mut fr_to_bytes_le(&root));
-        roots_buffer = Cursor::new(roots_serialized.clone());
+        roots_buffer = Cursor::new(roots_serialized);
         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);
@@ -1205,7 +1218,7 @@ mod stateless_test {
             .unwrap();
         let proof_data_3 = output_buffer.into_inner();
 
-        let mut input_proof_data_1 = Cursor::new(proof_data_1.clone());
+        let mut input_proof_data_1 = Cursor::new(proof_data_1);
         let mut input_proof_data_3 = Cursor::new(proof_data_3);
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
         rln.recover_id_secret(

rln/src/utils.rs

@@ -1,27 +1,28 @@
 // This crate provides cross-module useful utilities (mainly type conversions) not necessarily specific to RLN
 
 use crate::circuit::Fr;
+use crate::error::ConversionError;
 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;
 
-pub fn to_bigint(el: &Fr) -> Result<BigInt> {
-    let res: BigUint = (*el).into();
-    Ok(res.into())
+#[inline(always)]
+pub fn to_bigint(el: &Fr) -> BigInt {
+    BigUint::from(*el).into()
 }
 
+#[inline(always)]
 pub fn fr_byte_size() -> usize {
     let mbs = <Fr as PrimeField>::MODULUS_BIT_SIZE;
     ((mbs + 64 - (mbs % 64)) / 8) as usize
 }
 
-pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
+#[inline(always)]
+pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr, ConversionError> {
     if !(radix == 10 || radix == 16) {
-        return Err(Report::msg("wrong radix"));
+        return Err(ConversionError::WrongRadix);
     }
 
     // We remove any quote present and we trim
@@ -37,6 +38,7 @@ 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();
     (
@@ -45,78 +47,51 @@ 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.resize(fr_byte_size(), 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);
+#[inline(always)]
+pub fn vec_fr_to_bytes_le(input: &[Fr]) -> Vec<u8> {
+    // Calculate capacity for Vec:
+    // - 8 bytes for normalized vector length (usize)
+    // - each Fr element requires fr_byte_size() bytes (typically 32 bytes)
+    let mut bytes = Vec::with_capacity(8 + input.len() * fr_byte_size());
+
+    // We store the vector length
+    bytes.extend_from_slice(&normalize_usize(input.len()));
+
+    // We store each element
+    for el in input {
+        bytes.extend_from_slice(&fr_to_bytes_le(el));
     }
-    res
+
+    bytes
 }
 
-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());
+#[inline(always)]
+pub fn vec_u8_to_bytes_le(input: &[u8]) -> Vec<u8> {
+    // Calculate capacity for Vec:
+    // - 8 bytes for normalized vector length (usize)
+    // - variable length input data
+    let mut bytes = Vec::with_capacity(8 + input.len());
 
-    // We store each element
-    input.iter().for_each(|el| bytes.extend(fr_to_bytes_le(el)));
+    // We store the vector length
+    bytes.extend_from_slice(&normalize_usize(input.len()));
 
-    Ok(bytes)
+    // We store the input
+    bytes.extend_from_slice(input);
+
+    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)));
-
-    Ok(bytes)
-}
-
-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());
-
-    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);
-
-    Ok(bytes)
-}
-
-pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize)> {
+#[inline(always)]
+pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize), ConversionError> {
     let mut read: usize = 0;
 
     let len = usize::try_from(u64::from_le_bytes(input[0..8].try_into()?))?;
@@ -128,20 +103,8 @@ 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))
-}
-
-pub fn bytes_le_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize)> {
+#[inline(always)]
+pub fn bytes_le_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize), ConversionError> {
     let mut read: usize = 0;
     let mut res: Vec<Fr> = Vec::new();
 
@@ -158,30 +121,8 @@ 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
-}
-
-pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>> {
+#[inline(always)]
+pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>, ConversionError> {
     let nof_elem = usize::try_from(u64::from_le_bytes(input[0..8].try_into()?))?;
     if nof_elem == 0 {
         Ok(vec![])
@@ -194,141 +135,18 @@ pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>> {
     }
 }
 
-// using for test
+/// Normalizes a `usize` into an 8-byte array, ensuring consistency across architectures.
+/// On 32-bit systems, the result is zero-padded to 8 bytes.
+/// On 64-bit systems, it directly represents the `usize` value.
+#[inline(always)]
+pub fn normalize_usize(input: usize) -> [u8; 8] {
+    let mut bytes = [0u8; 8];
+    let input_bytes = input.to_le_bytes();
+    bytes[..input_bytes.len()].copy_from_slice(&input_bytes);
+    bytes
+}
+
+#[inline(always)] // using for test
 pub fn generate_input_buffer() -> Cursor<String> {
     Cursor::new(json!({}).to_string())
 }
-
-/* 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

@@ -3,7 +3,7 @@
 mod test {
     use ark_std::{rand::thread_rng, UniformRand};
     use rand::Rng;
-    use rln::circuit::*;
+    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
     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::protocol::*;
@@ -27,7 +27,7 @@ mod test {
     }
 
     fn set_leaves_init(rln_pointer: &mut RLN, leaves: &[Fr]) {
-        let leaves_ser = vec_fr_to_bytes_le(&leaves).unwrap();
+        let leaves_ser = vec_fr_to_bytes_le(&leaves);
         let input_buffer = &Buffer::from(leaves_ser.as_ref());
         let success = init_tree_with_leaves(rln_pointer, input_buffer);
         assert!(success, "init tree with leaves call failed");
@@ -156,6 +156,7 @@ mod test {
         // random number between 0..no_of_leaves
         let mut rng = thread_rng();
         let set_index = rng.gen_range(0..NO_OF_LEAVES) as usize;
+        println!("set_index: {}", set_index);
 
         // We add leaves in a batch into the tree
         set_leaves_init(rln_pointer, &leaves);
@@ -169,14 +170,17 @@ mod test {
         set_leaves_init(rln_pointer, &leaves[0..set_index]);
 
         // We add the remaining n leaves in a batch starting from index set_index
-        let leaves_n = vec_fr_to_bytes_le(&leaves[set_index..]).unwrap();
+        let leaves_n = vec_fr_to_bytes_le(&leaves[set_index..]);
         let buffer = &Buffer::from(leaves_n.as_ref());
         let success = set_leaves_from(rln_pointer, set_index, buffer);
         assert!(success, "set leaves from call failed");
 
         // We get the root of the tree obtained adding leaves in batch
         let root_batch_with_custom_index = get_tree_root(rln_pointer);
-        assert_eq!(root_batch_with_init, root_batch_with_custom_index);
+        assert_eq!(
+            root_batch_with_init, root_batch_with_custom_index,
+            "root batch !="
+        );
 
         // We reset the tree to default
         let success = set_tree(rln_pointer, TEST_TREE_HEIGHT);
@@ -192,7 +196,10 @@ mod test {
 
         // We get the root of the tree obtained adding leaves using the internal index
         let root_single_additions = get_tree_root(rln_pointer);
-        assert_eq!(root_batch_with_init, root_single_additions);
+        assert_eq!(
+            root_batch_with_init, root_single_additions,
+            "root single additions !="
+        );
     }
 
     #[test]
@@ -213,9 +220,9 @@ mod test {
         let last_leaf_index = NO_OF_LEAVES - 1;
         let indices = vec![last_leaf_index as u8];
         let last_leaf = vec![*last_leaf];
-        let indices = vec_u8_to_bytes_le(&indices).unwrap();
+        let indices = vec_u8_to_bytes_le(&indices);
         let indices_buffer = &Buffer::from(indices.as_ref());
-        let leaves = vec_fr_to_bytes_le(&last_leaf).unwrap();
+        let leaves = vec_fr_to_bytes_le(&last_leaf);
         let leaves_buffer = &Buffer::from(leaves.as_ref());
 
         let success = atomic_operation(
@@ -246,7 +253,7 @@ mod test {
         let root_empty = get_tree_root(rln_pointer);
 
         // We add leaves in a batch into the tree
-        let leaves = vec_fr_to_bytes_le(&leaves).unwrap();
+        let leaves = vec_fr_to_bytes_le(&leaves);
         let buffer = &Buffer::from(leaves.as_ref());
         let success = set_leaves_from(rln_pointer, bad_index, buffer);
         assert!(!success, "set leaves from call succeeded");
@@ -408,15 +415,6 @@ 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"))]
@@ -428,15 +426,17 @@ mod test {
             .read_exact(&mut zkey_buffer)
             .expect("buffer overflow");
 
-        let vk_path = "./resources/tree_height_20/verification_key.arkvkey";
-        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();
@@ -444,9 +444,8 @@ 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(),
         );
@@ -486,10 +485,13 @@ 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
@@ -500,27 +502,25 @@ 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);
@@ -553,11 +553,12 @@ 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);
@@ -567,24 +568,23 @@ 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
 
@@ -592,7 +592,7 @@ 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;
@@ -606,7 +606,7 @@ 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;
@@ -622,7 +622,7 @@ 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;
@@ -643,7 +643,6 @@ 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
@@ -665,36 +664,40 @@ 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());
@@ -737,18 +740,18 @@ 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)
 
@@ -889,7 +892,7 @@ mod test {
         for _ in 0..number_of_inputs {
             inputs.push(Fr::rand(&mut rng));
         }
-        let inputs_ser = vec_fr_to_bytes_le(&inputs).unwrap();
+        let inputs_ser = vec_fr_to_bytes_le(&inputs);
         let input_buffer = &Buffer::from(inputs_ser.as_ref());
 
         let expected_hash = utils_poseidon_hash(inputs.as_ref());
@@ -1211,15 +1214,14 @@ mod stateless_test {
         .unwrap();
 
         let serialized = serialize_witness(&rln_witness).unwrap();
-        let mut proof_data = rln_proof_gen_with_witness(rln_pointer, serialized.as_ref());
+        let proof_data = rln_proof_gen_with_witness(rln_pointer, serialized.as_ref());
 
-        proof_data.append(&mut normalize_usize(signal.len()));
-        proof_data.append(&mut signal.to_vec());
+        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(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;
@@ -1233,7 +1235,7 @@ mod stateless_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;
@@ -1248,7 +1250,7 @@ mod stateless_test {
 
         // 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(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;
@@ -1431,7 +1433,7 @@ mod stateless_test {
         for _ in 0..number_of_inputs {
             inputs.push(Fr::rand(&mut rng));
         }
-        let inputs_ser = vec_fr_to_bytes_le(&inputs).unwrap();
+        let inputs_ser = vec_fr_to_bytes_le(&inputs);
         let input_buffer = &Buffer::from(inputs_ser.as_ref());
 
         let expected_hash = utils_poseidon_hash(inputs.as_ref());

rln/tests/poseidon_tree.rs

@@ -5,7 +5,10 @@
 #[cfg(test)]
 mod test {
     use rln::hashers::{poseidon_hash, PoseidonHash};
-    use rln::{circuit::*, poseidon_tree::PoseidonTree};
+    use rln::{
+        circuit::{Fr, TEST_TREE_HEIGHT},
+        poseidon_tree::PoseidonTree,
+    };
     use utils::{FullMerkleTree, OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree};
 
     #[test]
@@ -23,6 +26,7 @@ mod test {
             assert_eq!(proof.leaf_index(), i);
 
             tree_opt.set(i, leaves[i]).unwrap();
+            assert_eq!(tree_opt.root(), tree_full.root());
             let proof = tree_opt.proof(i).expect("index should be set");
             assert_eq!(proof.leaf_index(), i);
         }
@@ -37,11 +41,11 @@ mod test {
     #[test]
     fn test_subtree_root() {
         const DEPTH: usize = 3;
-        const LEAVES_LEN: usize = 6;
+        const LEAVES_LEN: usize = 8;
 
         let mut tree = PoseidonTree::default(DEPTH).unwrap();
         let leaves: Vec<Fr> = (0..LEAVES_LEN).map(|s| Fr::from(s as i32)).collect();
-        let _ = tree.set_range(0, leaves);
+        let _ = tree.set_range(0, leaves.into_iter());
 
         for i in 0..LEAVES_LEN {
             // check leaves
@@ -78,7 +82,7 @@ mod test {
         let leaves: Vec<Fr> = (0..nof_leaves).map(|s| Fr::from(s as i32)).collect();
 
         // check set_range
-        let _ = tree.set_range(0, leaves.clone());
+        let _ = tree.set_range(0, leaves.clone().into_iter());
         assert!(tree.get_empty_leaves_indices().is_empty());
 
         let mut vec_idxs = Vec::new();
@@ -98,26 +102,28 @@ mod test {
         // check remove_indices_and_set_leaves inside override_range function
         assert!(tree.get_empty_leaves_indices().is_empty());
         let leaves_2: Vec<Fr> = (0..2).map(|s| Fr::from(s as i32)).collect();
-        tree.override_range(0, leaves_2.clone(), [0, 1, 2, 3])
+        tree.override_range(0, leaves_2.clone().into_iter(), [0, 1, 2, 3].into_iter())
             .unwrap();
         assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
 
         // check remove_indices inside override_range function
-        tree.override_range(0, [], [0, 1]).unwrap();
+        tree.override_range(0, [].into_iter(), [0, 1].into_iter())
+            .unwrap();
         assert_eq!(tree.get_empty_leaves_indices(), vec![0, 1, 2, 3]);
 
         // check set_range inside override_range function
-        tree.override_range(0, leaves_2.clone(), []).unwrap();
+        tree.override_range(0, leaves_2.clone().into_iter(), [].into_iter())
+            .unwrap();
         assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
 
         let leaves_4: Vec<Fr> = (0..4).map(|s| Fr::from(s as i32)).collect();
         // check if the indexes for write and delete are the same
-        tree.override_range(0, leaves_4.clone(), [0, 1, 2, 3])
+        tree.override_range(0, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
             .unwrap();
         assert!(tree.get_empty_leaves_indices().is_empty());
 
         // check if indexes for deletion are before indexes for overwriting
-        tree.override_range(4, leaves_4.clone(), [0, 1, 2, 3])
+        tree.override_range(4, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
             .unwrap();
         // The result will be like this, because in the set_range function in pmtree
         // the next_index value is increased not by the number of elements to insert,
@@ -128,7 +134,7 @@ mod test {
         );
 
         // check if the indices for write and delete do not overlap completely
-        tree.override_range(2, leaves_4.clone(), [0, 1, 2, 3])
+        tree.override_range(2, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
             .unwrap();
         // The result will be like this, because in the set_range function in pmtree
         // the next_index value is increased not by the number of elements to insert,

rln/tests/protocol.rs

@@ -1,11 +1,16 @@
 #[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::*;
+    use rln::protocol::{
+        deserialize_proof_values, deserialize_witness, generate_proof, keygen,
+        proof_values_from_witness, rln_witness_from_json, rln_witness_from_values,
+        rln_witness_to_json, seeded_keygen, serialize_proof_values, serialize_witness,
+        verify_proof, RLNWitnessInput,
+    };
     use rln::utils::str_to_fr;
     use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
 
@@ -128,9 +133,8 @@ mod test {
     fn test_witness_from_json() {
         // We generate all relevant keys
         let proving_key = zkey_from_folder();
-        let verification_key = vk_from_folder();
-        let builder = circom_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 +142,7 @@ 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
@@ -157,11 +161,11 @@ mod test {
 
         // We generate all relevant keys
         let proving_key = zkey_from_folder();
-        let verification_key = vk_from_folder();
-        let builder = circom_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

@@ -1,13 +1,21 @@
 #[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 rln::utils::{
+        bytes_le_to_fr, bytes_le_to_vec_fr, bytes_le_to_vec_u8, bytes_le_to_vec_usize,
+        fr_to_bytes_le, generate_input_buffer, str_to_fr, vec_fr_to_bytes_le,
+    };
     use std::io::Cursor;
 
     #[test]
@@ -238,7 +246,7 @@ mod test {
         }
         let expected_hash = utils_poseidon_hash(&inputs);
 
-        let mut input_buffer = Cursor::new(vec_fr_to_bytes_le(&inputs).unwrap());
+        let mut input_buffer = Cursor::new(vec_fr_to_bytes_le(&inputs));
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
 
         public_poseidon_hash(&mut input_buffer, &mut output_buffer).unwrap();

utils/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "zerokit_utils"
-version = "0.5.1"
+version = "0.6.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Various utilities for Zerokit"
@@ -12,29 +12,36 @@ 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",
+ark-ff = { version = "0.5.0", default-features = false, features = [
+    "parallel",
 ] }
-color-eyre = "=0.6.2"
-pmtree = { package = "vacp2p_pmtree", version = "=2.0.2", optional = true }
-sled = "=0.34.7"
-serde = "=1.0.163"
-lazy_static = "1.4.0"
-hex = "0.4"
+num-bigint = { version = "0.4.6", default-features = false }
+pmtree = { package = "vacp2p_pmtree", version = "2.0.2", optional = true }
+sled = "0.34.7"
+serde_json = "1.0"
+lazy_static = "1.5.0"
+hex = "0.4.3"
+rayon = "1.7.0"
+thiserror = "2.0"
 
 [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 = "0.4.1"
+tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+criterion = { version = "0.6.0", features = ["html_reports"] }
 
 [features]
-default = ["parallel"]
-parallel = ["ark-ff/parallel"]
+default = []
 pmtree-ft = ["pmtree"]
 
 [[bench]]
 name = "merkle_tree_benchmark"
 harness = false
+
+[[bench]]
+name = "poseidon_benchmark"
+harness = false
+
+[package.metadata.docs.rs]
+all-features = true

utils/Makefile.toml

@@ -8,4 +8,4 @@ args = ["test", "--release"]
 
 [tasks.bench]
 command = "cargo"
-args = ["bench"]
+args = ["bench"]

utils/README.md

@@ -1,15 +1,133 @@
-# Utils crate
+# Zerokit Utils Crate
 
-## Building
+[![Crates.io](https://img.shields.io/crates/v/zerokit_utils.svg)](https://crates.io/crates/zerokit_utils)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
 
-1. `cargo build`
+**Zerokit Utils** provides essential cryptographic primitives optimized for zero-knowledge applications.
+This crate features efficient Merkle tree implementations and a Poseidon hash function,
+designed to be robust and performant.
 
-## Testing
+## Overview
 
-1. `cargo test`
+This crate provides core cryptographic components optimized for zero-knowledge proof systems:
 
-## Benchmarking
+- **Multiple Merkle Trees**: Various implementations optimised for the trade-off between space and time.
+- **Poseidon Hash Function**: An efficient hashing algorithm suitable for ZK contexts, with customizable parameters.
+- **Parallel Performance**: Leverages Rayon for significant speed-ups in Merkle tree computations.
+- **Arkworks Compatibility**: Poseidon hash implementation is designed to work seamlessly
+  with Arkworks field traits and data structures.
 
-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
+Merkle trees are fundamental data structures for verifying data integrity and set membership.
+Zerokit Utils offers two interchangeable implementations:
+
+### Understanding Merkle Tree Terminology
+
+To better understand the structure and parameters of our Merkle trees, here's a quick glossary:
+
+- **Depth (`depth`)**: level of leaves if we count from root.
+  If the root is at level 0, leaves are at level `depth`.
+- **Number of Levels**: `depth + 1`.
+- **Capacity (Number of Leaves)**: $2^{\text{depth}}$. This is the maximum number of leaves the tree can hold.
+- **Total Number of Nodes**: $2^{(\text{depth} + 1)} - 1$ for a full binary tree.
+
+**Example for a tree with `depth: 3`**:
+
+- Number of Levels: 4 (levels 0, 1, 2, 3)
+- Capacity (Number of Leaves): $2^3 = 8$
+- Total Number of Nodes: $2^{(3+1)} - 1 = 15$
+
+Visual representation of a Merkle tree with `depth: 3`:
+
+```mermaid
+flowchart TD
+    A[Root] --> N1
+    A[Root] --> N2
+    N1 --> N3
+    N1 --> N4
+    N2 --> N5
+    N2 --> N6
+    N3 -->|Leaf| L1
+    N3 -->|Leaf| L2
+    N4 -->|Leaf| L3
+    N4 -->|Leaf| L4
+    N5 -->|Leaf| L5
+    N5 -->|Leaf| L6
+    N6 -->|Leaf| L7
+    N6 -->|Leaf| L8
+```
+
+### Available Implementations
+
+- **FullMerkleTree**
+  - Stores all tree nodes in memory.
+  - Use Case: Use when memory is abundant and operation speed is critical.
+
+- **OptimalMerkleTree**
+  - Stores only the nodes required to prove the accumulation of set leaves (i.e., authentication paths).
+  - Use Case: Suited for environments where memory efficiency is a higher priority than raw speed.
+
+#### Parallel Processing with Rayon
+
+Both `OptimalMerkleTree` and `FullMerkleTree` internally utilize the Rayon crate
+to accelerate computations through data parallelism.
+This can lead to significant performance improvements, particularly during updates to large Merkle trees.
+
+## Poseidon Hash Implementation
+
+This crate provides an implementation for computing Poseidon hash round constants and MDS matrices.
+Key characteristics include:
+
+- **Customizable parameters**: Supports various security levels and input sizes,
+  allowing you to tailor the hash function to your specific needs.
+- **Arkworks-friendly**: Adapted to integrate smoothly with Arkworks field traits and custom data structures.
+
+### ⚠️ Security Note
+
+The MDS matrices used in the Poseidon hash function are generated iteratively
+using the Grain LFSR (Linear Feedback Shift Register) algorithm until specific cryptographic criteria are met.
+
+- The reference Poseidon implementation includes validation algorithms to ensure these criteria are satisfied.
+  These validation algorithms are not currently implemented in this crate.
+- For the hardcoded parameters provided within this crate,
+  the initially generated random matrix has been verified to meet these conditions.
+- If you intend to use custom parameters, it is crucial to verify your generated MDS matrix.
+  You should consult the Poseidon reference implementation to determine
+  how many matrices are typically skipped before a valid one is found.
+  This count should then be passed as the `skip_matrices parameter` to the `find_poseidon_ark_and_mds`
+  function in this crate.
+
+## Installation
+
+Add zerokit-utils as a dependency to your Cargo.toml file:
+
+```toml
+[dependencies]
+zerokit-utils = "0.6.0"
+```
+
+## Building and Testing
+
+```bash
+# Build the crate
+cargo make build
+
+# Run tests
+cargo make test
+
+# Run benchmarks
+cargo make 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/benches/merkle_tree_benchmark.rs

@@ -1,7 +1,7 @@
-use criterion::{criterion_group, criterion_main, Criterion};
-use hex_literal::hex;
-use lazy_static::lazy_static;
 use std::{fmt::Display, str::FromStr};
+
+use criterion::{criterion_group, criterion_main, Criterion};
+use lazy_static::lazy_static;
 use tiny_keccak::{Hasher as _, Keccak};
 use zerokit_utils::{
     FullMerkleConfig, FullMerkleTree, Hasher, OptimalMerkleConfig, OptimalMerkleTree,
@@ -47,54 +47,78 @@ impl FromStr for TestFr {
 }
 
 lazy_static! {
-    static ref LEAVES: [TestFr; 4] = [
-        hex!("0000000000000000000000000000000000000000000000000000000000000001"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000002"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000003"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-    ]
-    .map(TestFr);
+    static ref LEAVES: Vec<TestFr> = {
+        let mut leaves = Vec::with_capacity(1 << 20);
+        for i in 0..(1 << 20) {
+            let mut bytes = [0u8; 32];
+            bytes[28..].copy_from_slice(&(i as u32).to_be_bytes());
+            leaves.push(TestFr(bytes));
+        }
+        leaves
+    };
+    static ref INDICES: Vec<usize> = (0..(1 << 20)).collect();
 }
 
+const NOF_LEAVES: usize = 8192;
+
 pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
     let mut tree =
-        OptimalMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), OptimalMerkleConfig::default())
+        OptimalMerkleTree::<Keccak256>::new(20, TestFr([0; 32]), OptimalMerkleConfig::default())
             .unwrap();
 
+    for i in 0..NOF_LEAVES {
+        tree.set(i, LEAVES[i % LEAVES.len()]).unwrap();
+    }
+
     c.bench_function("OptimalMerkleTree::set", |b| {
+        let mut index = NOF_LEAVES;
         b.iter(|| {
-            tree.set(0, LEAVES[0]).unwrap();
+            tree.set(index % (1 << 20), LEAVES[index % LEAVES.len()])
+                .unwrap();
+            index = (index + 1) % (1 << 20);
         })
     });
 
     c.bench_function("OptimalMerkleTree::delete", |b| {
+        let mut index = 0;
         b.iter(|| {
-            tree.delete(0).unwrap();
+            tree.delete(index % NOF_LEAVES).unwrap();
+            tree.set(index % NOF_LEAVES, LEAVES[index % LEAVES.len()])
+                .unwrap();
+            index = (index + 1) % NOF_LEAVES;
         })
     });
 
     c.bench_function("OptimalMerkleTree::override_range", |b| {
+        let mut offset = 0;
         b.iter(|| {
-            tree.override_range(0, *LEAVES, [0, 1, 2, 3]).unwrap();
-        })
-    });
-
-    c.bench_function("OptimalMerkleTree::compute_root", |b| {
-        b.iter(|| {
-            tree.compute_root().unwrap();
+            let range = offset..offset + NOF_LEAVES;
+            tree.override_range(
+                offset,
+                LEAVES[range.clone()].iter().cloned(),
+                INDICES[range.clone()].iter().cloned(),
+            )
+            .unwrap();
+            offset = (offset + NOF_LEAVES) % (1 << 20);
         })
     });
 
     c.bench_function("OptimalMerkleTree::get", |b| {
+        let mut index = 0;
         b.iter(|| {
-            tree.get(0).unwrap();
+            tree.get(index % NOF_LEAVES).unwrap();
+            index = (index + 1) % NOF_LEAVES;
         })
     });
 
-    // check intermediate node getter which required additional computation of sub root index
     c.bench_function("OptimalMerkleTree::get_subtree_root", |b| {
+        let mut level = 1;
+        let mut index = 0;
         b.iter(|| {
-            tree.get_subtree_root(1, 0).unwrap();
+            tree.get_subtree_root(level % 20, index % (1 << (20 - (level % 20))))
+                .unwrap();
+            index = (index + 1) % (1 << (20 - (level % 20)));
+            level = 1 + (level % 20);
         })
     });
 
@@ -107,42 +131,61 @@ pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
 
 pub fn full_merkle_tree_benchmark(c: &mut Criterion) {
     let mut tree =
-        FullMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), FullMerkleConfig::default()).unwrap();
+        FullMerkleTree::<Keccak256>::new(20, TestFr([0; 32]), FullMerkleConfig::default()).unwrap();
+
+    for i in 0..NOF_LEAVES {
+        tree.set(i, LEAVES[i % LEAVES.len()]).unwrap();
+    }
 
     c.bench_function("FullMerkleTree::set", |b| {
+        let mut index = NOF_LEAVES;
         b.iter(|| {
-            tree.set(0, LEAVES[0]).unwrap();
+            tree.set(index % (1 << 20), LEAVES[index % LEAVES.len()])
+                .unwrap();
+            index = (index + 1) % (1 << 20);
         })
     });
 
     c.bench_function("FullMerkleTree::delete", |b| {
+        let mut index = 0;
         b.iter(|| {
-            tree.delete(0).unwrap();
+            tree.delete(index % NOF_LEAVES).unwrap();
+            tree.set(index % NOF_LEAVES, LEAVES[index % LEAVES.len()])
+                .unwrap();
+            index = (index + 1) % NOF_LEAVES;
         })
     });
 
     c.bench_function("FullMerkleTree::override_range", |b| {
+        let mut offset = 0;
         b.iter(|| {
-            tree.override_range(0, *LEAVES, [0, 1, 2, 3]).unwrap();
-        })
-    });
-
-    c.bench_function("FullMerkleTree::compute_root", |b| {
-        b.iter(|| {
-            tree.compute_root().unwrap();
+            let range = offset..offset + NOF_LEAVES;
+            tree.override_range(
+                offset,
+                LEAVES[range.clone()].iter().cloned(),
+                INDICES[range.clone()].iter().cloned(),
+            )
+            .unwrap();
+            offset = (offset + NOF_LEAVES) % (1 << 20);
         })
     });
 
     c.bench_function("FullMerkleTree::get", |b| {
+        let mut index = 0;
         b.iter(|| {
-            tree.get(0).unwrap();
+            tree.get(index % NOF_LEAVES).unwrap();
+            index = (index + 1) % NOF_LEAVES;
         })
     });
 
-    // check intermediate node getter which required additional computation of sub root index
     c.bench_function("FullMerkleTree::get_subtree_root", |b| {
+        let mut level = 1;
+        let mut index = 0;
         b.iter(|| {
-            tree.get_subtree_root(1, 0).unwrap();
+            tree.get_subtree_root(level % 20, index % (1 << (20 - (level % 20))))
+                .unwrap();
+            index = (index + 1) % (1 << (20 - (level % 20)));
+            level = 1 + (level % 20);
         })
     });
 

utils/benches/poseidon_benchmark.rs

@@ -0,0 +1,65 @@
+use std::hint::black_box;
+
+use ark_bn254::Fr;
+use criterion::{criterion_group, criterion_main, BatchSize, BenchmarkId, Criterion, Throughput};
+use zerokit_utils::Poseidon;
+
+const ROUND_PARAMS: [(usize, usize, usize, usize); 8] = [
+    (2, 8, 56, 0),
+    (3, 8, 57, 0),
+    (4, 8, 56, 0),
+    (5, 8, 60, 0),
+    (6, 8, 60, 0),
+    (7, 8, 63, 0),
+    (8, 8, 64, 0),
+    (9, 8, 63, 0),
+];
+
+pub fn poseidon_benchmark(c: &mut Criterion) {
+    let hasher = Poseidon::<Fr>::from(&ROUND_PARAMS);
+    let mut group = c.benchmark_group("poseidon Fr");
+
+    for size in [10u32, 100, 1000].iter() {
+        group.throughput(Throughput::Elements(*size as u64));
+
+        group.bench_with_input(BenchmarkId::new("Array hash", size), size, |b, &size| {
+            b.iter_batched(
+                // Setup: create values for each benchmark iteration
+                || {
+                    let mut values = Vec::with_capacity(size as usize);
+                    for i in 0..size {
+                        values.push([Fr::from(i)]);
+                    }
+                    values
+                },
+                // Actual benchmark
+                |values| {
+                    for v in values.iter() {
+                        let _ = hasher.hash(black_box(&v[..]));
+                    }
+                },
+                BatchSize::SmallInput,
+            )
+        });
+    }
+
+    // Benchmark single hash operation separately
+    group.bench_function("Single hash", |b| {
+        let input = [Fr::from(u64::MAX)];
+        b.iter(|| {
+            let _ = hasher.hash(black_box(&input[..]));
+        })
+    });
+
+    group.finish();
+}
+
+criterion_group! {
+    name = benches;
+    config = Criterion::default()
+        .warm_up_time(std::time::Duration::from_millis(500))
+        .measurement_time(std::time::Duration::from_secs(4))
+        .sample_size(20);
+    targets = poseidon_benchmark
+}
+criterion_main!(benches);

utils/src/merkle_tree/error.rs

@@ -0,0 +1,31 @@
+#[derive(thiserror::Error, Debug)]
+pub enum ZerokitMerkleTreeError {
+    #[error("Invalid index")]
+    InvalidIndex,
+    // InvalidProof,
+    #[error("Leaf index out of bounds")]
+    InvalidLeaf,
+    #[error("Level exceeds tree depth")]
+    InvalidLevel,
+    #[error("Subtree index out of bounds")]
+    InvalidSubTreeIndex,
+    #[error("Start level is != from end level")]
+    InvalidStartAndEndLevel,
+    #[error("set_range got too many leaves")]
+    TooManySet,
+    #[error("Unknown error while computing merkle proof")]
+    ComputingProofError,
+    #[error("Invalid witness length (!= tree depth)")]
+    InvalidWitness,
+    #[cfg(feature = "pmtree-ft")]
+    #[error("Pmtree error: {0}")]
+    PmtreeErrorKind(#[from] pmtree::PmtreeErrorKind),
+}
+
+#[derive(Debug, thiserror::Error)]
+pub enum FromConfigError {
+    #[error("Error while reading pmtree config: {0}")]
+    JsonError(#[from] serde_json::Error),
+    #[error("Error while creating pmtree config: path already exists")]
+    PathExists,
+}

utils/src/merkle_tree/full_merkle_tree.rs

@@ -1,28 +1,29 @@
-use crate::merkle_tree::{FrOf, Hasher, ZerokitMerkleProof, ZerokitMerkleTree};
-use color_eyre::{Report, Result};
 use std::{
     cmp::max,
     fmt::Debug,
-    iter::{once, repeat, successors},
+    iter::{once, repeat_n},
     str::FromStr,
 };
 
+use rayon::iter::{IntoParallelIterator, ParallelIterator};
+
+use crate::merkle_tree::{
+    error::{FromConfigError, ZerokitMerkleTreeError},
+    FrOf, Hasher, ZerokitMerkleProof, ZerokitMerkleTree, MIN_PARALLEL_NODES,
+};
 ////////////////////////////////////////////////////////////
-/// Full Merkle Tree Implementation
+///// Full Merkle Tree Implementation
 ////////////////////////////////////////////////////////////
 
 /// Merkle tree with all leaf and intermediate hashes stored
 #[derive(Clone, PartialEq, Eq, Debug)]
-pub struct FullMerkleTree<H: Hasher> {
+pub struct FullMerkleTree<H>
+where
+    H: Hasher,
+{
     /// The depth of the tree, i.e. the number of levels from leaf to root
     depth: usize,
 
-    /// The nodes cached from the empty part of the tree (where leaves are set to default).
-    /// Since the rightmost part of the tree is usually changed much later than its creation,
-    /// we can prove accumulation of elements in the leftmost part, with no need to initialize the full tree
-    /// and by caching few intermediate nodes to the root computed from default leaves
-    cached_nodes: Vec<H::Fr>,
-
     /// The tree nodes
     nodes: Vec<H::Fr>,
 
@@ -30,11 +31,11 @@ pub struct FullMerkleTree<H: Hasher> {
     /// Set to 0 if the leaf is empty and set to 1 in otherwise.
     cached_leaves_indices: Vec<u8>,
 
-    // The next available (i.e., never used) tree index. Equivalently, the number of leaves added to the tree
-    // (deletions leave next_index unchanged)
+    /// The next available (i.e., never used) tree index. Equivalently, the number of leaves added to the tree
+    /// (deletions leave next_index unchanged)
     next_index: usize,
 
-    // metadata that an application may use to store additional information
+    /// metadata that an application may use to store additional information
     metadata: Vec<u8>,
 }
 
@@ -56,9 +57,9 @@ pub struct FullMerkleProof<H: Hasher>(pub Vec<FullMerkleBranch<H>>);
 pub struct FullMerkleConfig(());
 
 impl FromStr for FullMerkleConfig {
-    type Err = Report;
+    type Err = FromConfigError;
 
-    fn from_str(_s: &str) -> Result<Self> {
+    fn from_str(_s: &str) -> Result<Self, Self::Err> {
         Ok(FullMerkleConfig::default())
     }
 }
@@ -72,86 +73,89 @@ where
     type Hasher = H;
     type Config = FullMerkleConfig;
 
-    fn default(depth: usize) -> Result<Self> {
+    fn default(depth: usize) -> Result<Self, ZerokitMerkleTreeError> {
         FullMerkleTree::<H>::new(depth, Self::Hasher::default_leaf(), Self::Config::default())
     }
 
     /// Creates a new `MerkleTree`
     /// depth - the height of the tree made only of hash nodes. 2^depth is the maximum number of leaves hash nodes
-    fn new(depth: usize, initial_leaf: FrOf<Self::Hasher>, _config: Self::Config) -> Result<Self> {
+    fn new(
+        depth: usize,
+        default_leaf: FrOf<Self::Hasher>,
+        _config: Self::Config,
+    ) -> Result<Self, ZerokitMerkleTreeError> {
         // Compute cache node values, leaf to root
-        let cached_nodes = successors(Some(initial_leaf), |prev| Some(H::hash(&[*prev, *prev])))
-            .take(depth + 1)
-            .collect::<Vec<_>>();
+        let mut cached_nodes: Vec<H::Fr> = Vec::with_capacity(depth + 1);
+        cached_nodes.push(default_leaf);
+        for i in 0..depth {
+            cached_nodes.push(H::hash(&[cached_nodes[i]; 2]));
+        }
+        cached_nodes.reverse();
 
         // Compute node values
         let nodes = cached_nodes
             .iter()
-            .rev()
             .enumerate()
-            .flat_map(|(levels, hash)| repeat(hash).take(1 << levels))
+            .flat_map(|(levels, hash)| repeat_n(hash, 1 << levels))
             .cloned()
             .collect::<Vec<_>>();
         debug_assert!(nodes.len() == (1 << (depth + 1)) - 1);
 
-        let next_index = 0;
-
         Ok(Self {
             depth,
-            cached_nodes,
             nodes,
             cached_leaves_indices: vec![0; 1 << depth],
-            next_index,
+            next_index: 0,
             metadata: Vec::new(),
         })
     }
 
-    fn close_db_connection(&mut self) -> Result<()> {
+    fn close_db_connection(&mut self) -> Result<(), ZerokitMerkleTreeError> {
         Ok(())
     }
 
-    // Returns the depth of the tree
+    /// Returns the depth of the tree
     fn depth(&self) -> usize {
         self.depth
     }
 
-    // Returns the capacity of the tree, i.e. the maximum number of accumulatable leaves
+    /// Returns the capacity of the tree, i.e. the maximum number of accumulatable leaves
     fn capacity(&self) -> usize {
         1 << self.depth
     }
 
-    // Returns the total number of leaves set
+    /// Returns the total number of leaves set
     fn leaves_set(&self) -> usize {
         self.next_index
     }
 
-    #[must_use]
-    // Returns the root of the tree
+    /// Returns the root of the tree
     fn root(&self) -> FrOf<Self::Hasher> {
         self.nodes[0]
     }
 
-    // Sets a leaf at the specified tree index
-    fn set(&mut self, leaf: usize, hash: FrOf<Self::Hasher>) -> Result<()> {
+    /// Sets a leaf at the specified tree index
+    fn set(&mut self, leaf: usize, hash: FrOf<Self::Hasher>) -> Result<(), ZerokitMerkleTreeError> {
         self.set_range(leaf, once(hash))?;
         self.next_index = max(self.next_index, leaf + 1);
         Ok(())
     }
 
-    // Get a leaf from the specified tree index
-    fn get(&self, leaf: usize) -> Result<FrOf<Self::Hasher>> {
+    /// Get a leaf from the specified tree index
+    fn get(&self, leaf: usize) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError> {
         if leaf >= self.capacity() {
-            return Err(Report::msg("leaf index out of bounds"));
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
         }
         Ok(self.nodes[self.capacity() + leaf - 1])
     }
 
-    fn get_subtree_root(&self, n: usize, index: usize) -> Result<H::Fr> {
+    /// Returns the root of the subtree at level n and index
+    fn get_subtree_root(&self, n: usize, index: usize) -> Result<H::Fr, ZerokitMerkleTreeError> {
         if n > self.depth() {
-            return Err(Report::msg("level exceeds depth size"));
+            return Err(ZerokitMerkleTreeError::InvalidIndex);
         }
         if index >= self.capacity() {
-            return Err(Report::msg("index exceeds set size"));
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
         }
         if n == 0 {
             Ok(self.root())
@@ -161,7 +165,7 @@ where
             let mut idx = self.capacity() + index - 1;
             let mut nd = self.depth;
             loop {
-                let parent = self.parent(idx).unwrap();
+                let parent = self.parent(idx).expect("parent should exist");
                 nd -= 1;
                 if nd == n {
                     return Ok(self.nodes[parent]);
@@ -172,6 +176,8 @@ where
             }
         }
     }
+
+    /// Returns the indices of the leaves that are empty
     fn get_empty_leaves_indices(&self) -> Vec<usize> {
         self.cached_leaves_indices
             .iter()
@@ -182,40 +188,45 @@ where
             .collect()
     }
 
-    // Sets tree nodes, starting from start index
-    // Function proper of FullMerkleTree implementation
-    fn set_range<I: IntoIterator<Item = FrOf<Self::Hasher>>>(
+    /// Sets multiple leaves from the specified tree index
+    fn set_range<I: ExactSizeIterator<Item = FrOf<Self::Hasher>>>(
         &mut self,
         start: usize,
-        hashes: I,
-    ) -> Result<()> {
+        leaves: I,
+    ) -> Result<(), ZerokitMerkleTreeError> {
         let index = self.capacity() + start - 1;
         let mut count = 0;
-        // first count number of hashes, and check that they fit in the tree
+        // first count number of leaves, and check that they fit in the tree
         // then insert into the tree
-        let hashes = hashes.into_iter().collect::<Vec<_>>();
-        if hashes.len() + start > self.capacity() {
-            return Err(Report::msg("provided hashes do not fit in the tree"));
+        let leaves = leaves.into_iter().collect::<Vec<_>>();
+        if leaves.len() + start > self.capacity() {
+            return Err(ZerokitMerkleTreeError::TooManySet);
         }
-        hashes.into_iter().for_each(|hash| {
+        leaves.into_iter().for_each(|hash| {
             self.nodes[index + count] = hash;
             self.cached_leaves_indices[start + count] = 1;
             count += 1;
         });
         if count != 0 {
-            self.update_nodes(index, index + (count - 1))?;
+            self.update_hashes(index, index + (count - 1))?;
             self.next_index = max(self.next_index, start + count);
         }
         Ok(())
     }
 
-    fn override_range<I, J>(&mut self, start: usize, leaves: I, indices: J) -> Result<()>
+    /// Overrides a range of leaves while resetting specified indices to default and preserving unaffected values.
+    fn override_range<I, J>(
+        &mut self,
+        start: usize,
+        leaves: I,
+        indices: J,
+    ) -> Result<(), ZerokitMerkleTreeError>
     where
-        I: IntoIterator<Item = FrOf<Self::Hasher>>,
-        J: IntoIterator<Item = usize>,
+        I: ExactSizeIterator<Item = FrOf<Self::Hasher>>,
+        J: ExactSizeIterator<Item = usize>,
     {
         let indices = indices.into_iter().collect::<Vec<_>>();
-        let min_index = *indices.first().unwrap();
+        let min_index = *indices.first().expect("indices should not be empty");
         let leaves_vec = leaves.into_iter().collect::<Vec<_>>();
 
         let max_index = start + leaves_vec.len();
@@ -237,18 +248,17 @@ where
             self.cached_leaves_indices[i] = 0;
         }
 
-        self.set_range(start, set_values)
-            .map_err(|e| Report::msg(e.to_string()))
+        self.set_range(start, set_values.into_iter())
     }
 
-    // Sets a leaf at the next available index
-    fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<()> {
+    /// Sets a leaf at the next available index
+    fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<(), ZerokitMerkleTreeError> {
         self.set(self.next_index, leaf)?;
         Ok(())
     }
 
-    // Deletes a leaf at a certain index by setting it to its default value (next_index is not updated)
-    fn delete(&mut self, index: usize) -> Result<()> {
+    /// Deletes a leaf at a certain index by setting it to its default value (next_index is not updated)
+    fn delete(&mut self, index: usize) -> Result<(), ZerokitMerkleTreeError> {
         // We reset the leaf only if we previously set a leaf at that index
         if index < self.next_index {
             self.set(index, H::default_leaf())?;
@@ -257,10 +267,10 @@ where
         Ok(())
     }
 
-    // Computes a merkle proof the the leaf at the specified index
-    fn proof(&self, leaf: usize) -> Result<FullMerkleProof<H>> {
+    // Computes a merkle proof the leaf at the specified index
+    fn proof(&self, leaf: usize) -> Result<FullMerkleProof<H>, ZerokitMerkleTreeError> {
         if leaf >= self.capacity() {
-            return Err(Report::msg("index exceeds set size"));
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
         }
         let mut index = self.capacity() + leaf - 1;
         let mut path = Vec::with_capacity(self.depth + 1);
@@ -277,30 +287,29 @@ where
     }
 
     // Verifies a Merkle proof with respect to the input leaf and the tree root
-    fn verify(&self, hash: &FrOf<Self::Hasher>, proof: &FullMerkleProof<H>) -> Result<bool> {
+    fn verify(
+        &self,
+        hash: &FrOf<Self::Hasher>,
+        proof: &FullMerkleProof<H>,
+    ) -> Result<bool, ZerokitMerkleTreeError> {
         Ok(proof.compute_root_from(hash) == self.root())
     }
 
-    fn compute_root(&mut self) -> Result<FrOf<Self::Hasher>> {
-        Ok(self.root())
-    }
-
-    fn set_metadata(&mut self, metadata: &[u8]) -> Result<()> {
+    fn set_metadata(&mut self, metadata: &[u8]) -> Result<(), ZerokitMerkleTreeError> {
         self.metadata = metadata.to_vec();
         Ok(())
     }
 
-    fn metadata(&self) -> Result<Vec<u8>> {
+    fn metadata(&self) -> Result<Vec<u8>, ZerokitMerkleTreeError> {
         Ok(self.metadata.to_vec())
     }
 }
 
+// Utilities for updating the tree nodes
 impl<H: Hasher> FullMerkleTree<H>
 where
     H: Hasher,
 {
-    // Utilities for updating the tree nodes
-
     /// For a given node index, return the parent node index
     /// Returns None if there is no parent (root node)
     fn parent(&self, index: usize) -> Option<usize> {
@@ -316,23 +325,60 @@ where
         (index << 1) + 1
     }
 
+    /// Returns the depth level of a node based on its index in the flattened tree.
     fn levels(&self, index: usize) -> usize {
         // `n.next_power_of_two()` will return `n` iff `n` is a power of two.
         // The extra offset corrects this.
         (index + 2).next_power_of_two().trailing_zeros() as usize - 1
     }
 
-    fn update_nodes(&mut self, start: usize, end: usize) -> Result<()> {
-        if self.levels(start) != self.levels(end) {
-            return Err(Report::msg("self.levels(start) != self.levels(end)"));
+    /// Updates parent hashes after modifying a range of nodes at the same level.
+    ///
+    /// - `start_index`: The first index at the current level that was updated.
+    /// - `end_index`: The last index (inclusive) at the same level that was updated.
+    fn update_hashes(
+        &mut self,
+        start_index: usize,
+        end_index: usize,
+    ) -> Result<(), ZerokitMerkleTreeError> {
+        // Ensure the range is within the same tree level
+        if self.levels(start_index) != self.levels(end_index) {
+            return Err(ZerokitMerkleTreeError::InvalidStartAndEndLevel);
         }
-        if let (Some(start), Some(end)) = (self.parent(start), self.parent(end)) {
-            for parent in start..=end {
-                let child = self.first_child(parent);
-                self.nodes[parent] = H::hash(&[self.nodes[child], self.nodes[child + 1]]);
+
+        // Compute parent indices for the range
+        if let (Some(start_parent), Some(end_parent)) =
+            (self.parent(start_index), self.parent(end_index))
+        {
+            // Use parallel processing when the number of pairs exceeds the threshold
+            if end_parent - start_parent + 1 >= MIN_PARALLEL_NODES {
+                let updates: Vec<(usize, H::Fr)> = (start_parent..=end_parent)
+                    .into_par_iter()
+                    .map(|parent| {
+                        let left_child = self.first_child(parent);
+                        let right_child = left_child + 1;
+                        let hash = H::hash(&[self.nodes[left_child], self.nodes[right_child]]);
+                        (parent, hash)
+                    })
+                    .collect();
+
+                for (parent, hash) in updates {
+                    self.nodes[parent] = hash;
+                }
+            } else {
+                // Otherwise, fallback to sequential update for small ranges
+                for parent in start_parent..=end_parent {
+                    let left_child = self.first_child(parent);
+                    let right_child = left_child + 1;
+                    self.nodes[parent] =
+                        H::hash(&[self.nodes[left_child], self.nodes[right_child]]);
+                }
             }
-            self.update_nodes(start, end)?;
+
+            // Recurse to update upper levels
+            self.update_hashes(start_parent, end_parent)?;
         }
+
         Ok(())
     }
 }
@@ -341,14 +387,12 @@ impl<H: Hasher> ZerokitMerkleProof for FullMerkleProof<H> {
     type Index = u8;
     type Hasher = H;
 
-    #[must_use]
     // Returns the length of a Merkle proof
     fn length(&self) -> usize {
         self.0.len()
     }
 
     /// Computes the leaf index corresponding to a Merkle proof
-    #[must_use]
     fn leaf_index(&self) -> usize {
         self.0.iter().rev().fold(0, |index, branch| match branch {
             FullMerkleBranch::Left(_) => index << 1,
@@ -356,7 +400,6 @@ impl<H: Hasher> ZerokitMerkleProof for FullMerkleProof<H> {
         })
     }
 
-    #[must_use]
     /// Returns the path elements forming a Merkle proof
     fn get_path_elements(&self) -> Vec<FrOf<Self::Hasher>> {
         self.0
@@ -368,7 +411,6 @@ impl<H: Hasher> ZerokitMerkleProof for FullMerkleProof<H> {
     }
 
     /// Returns the path indexes forming a Merkle proof
-    #[must_use]
     fn get_path_index(&self) -> Vec<Self::Index> {
         self.0
             .iter()
@@ -380,7 +422,6 @@ impl<H: Hasher> ZerokitMerkleProof for FullMerkleProof<H> {
     }
 
     /// Computes the Merkle root corresponding by iteratively hashing a Merkle proof with a given input leaf
-    #[must_use]
     fn compute_root_from(&self, hash: &FrOf<Self::Hasher>) -> FrOf<Self::Hasher> {
         self.0.iter().fold(*hash, |hash, branch| match branch {
             FullMerkleBranch::Left(sibling) => H::hash(&[hash, *sibling]),

utils/src/merkle_tree/merkle_tree.rs

@@ -8,20 +8,25 @@
 // and https://github.com/worldcoin/semaphore-rs/blob/d462a4372f1fd9c27610f2acfe4841fab1d396aa/src/merkle_tree.rs
 
 //!
-//! # To do
+//! # TODO
 //!
 //! * Disk based storage backend (using mmaped files should be easy)
 //! * Implement serialization for tree and Merkle proof
 
-use std::str::FromStr;
+use crate::merkle_tree::error::ZerokitMerkleTreeError;
+use std::{
+    fmt::{Debug, Display},
+    str::FromStr,
+};
 
-use color_eyre::Result;
+/// Enables parallel hashing when there are at least 8 nodes (4 pairs to hash), justifying the overhead.
+pub const MIN_PARALLEL_NODES: usize = 8;
 
 /// In the Hasher trait we define the node type, the default leaf
 /// and the hash function used to initialize a Merkle Tree implementation
 pub trait Hasher {
     /// Type of the leaf and tree node
-    type Fr: Clone + Copy + Eq + Default + std::fmt::Debug + std::fmt::Display + FromStr;
+    type Fr: Clone + Copy + Eq + Default + Debug + Display + FromStr + Send + Sync;
 
     /// Returns the default tree leaf
     fn default_leaf() -> Self::Fr;
@@ -39,35 +44,52 @@ pub trait ZerokitMerkleTree {
     type Hasher: Hasher;
     type Config: Default + FromStr;
 
-    fn default(depth: usize) -> Result<Self>
+    fn default(depth: usize) -> Result<Self, ZerokitMerkleTreeError>
     where
         Self: Sized;
-    fn new(depth: usize, default_leaf: FrOf<Self::Hasher>, config: Self::Config) -> Result<Self>
+    fn new(
+        depth: usize,
+        default_leaf: FrOf<Self::Hasher>,
+        config: Self::Config,
+    ) -> Result<Self, ZerokitMerkleTreeError>
     where
         Self: Sized;
     fn depth(&self) -> usize;
     fn capacity(&self) -> usize;
     fn leaves_set(&self) -> usize;
     fn root(&self) -> FrOf<Self::Hasher>;
-    fn compute_root(&mut self) -> Result<FrOf<Self::Hasher>>;
-    fn get_subtree_root(&self, n: usize, index: usize) -> Result<FrOf<Self::Hasher>>;
-    fn set(&mut self, index: usize, leaf: FrOf<Self::Hasher>) -> Result<()>;
-    fn set_range<I>(&mut self, start: usize, leaves: I) -> Result<()>
+    fn get_subtree_root(
+        &self,
+        n: usize,
+        index: usize,
+    ) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError>;
+    fn set(&mut self, index: usize, leaf: FrOf<Self::Hasher>)
+        -> Result<(), ZerokitMerkleTreeError>;
+    fn set_range<I>(&mut self, start: usize, leaves: I) -> Result<(), ZerokitMerkleTreeError>
     where
-        I: IntoIterator<Item = FrOf<Self::Hasher>>;
-    fn get(&self, index: usize) -> Result<FrOf<Self::Hasher>>;
+        I: ExactSizeIterator<Item = FrOf<Self::Hasher>>;
+    fn get(&self, index: usize) -> Result<FrOf<Self::Hasher>, ZerokitMerkleTreeError>;
     fn get_empty_leaves_indices(&self) -> Vec<usize>;
-    fn override_range<I, J>(&mut self, start: usize, leaves: I, to_remove_indices: J) -> Result<()>
+    fn override_range<I, J>(
+        &mut self,
+        start: usize,
+        leaves: I,
+        to_remove_indices: J,
+    ) -> Result<(), ZerokitMerkleTreeError>
     where
-        I: IntoIterator<Item = FrOf<Self::Hasher>>,
-        J: IntoIterator<Item = usize>;
-    fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<()>;
-    fn delete(&mut self, index: usize) -> Result<()>;
-    fn proof(&self, index: usize) -> Result<Self::Proof>;
-    fn verify(&self, leaf: &FrOf<Self::Hasher>, witness: &Self::Proof) -> Result<bool>;
-    fn set_metadata(&mut self, metadata: &[u8]) -> Result<()>;
-    fn metadata(&self) -> Result<Vec<u8>>;
-    fn close_db_connection(&mut self) -> Result<()>;
+        I: ExactSizeIterator<Item = FrOf<Self::Hasher>>,
+        J: ExactSizeIterator<Item = usize>;
+    fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<(), ZerokitMerkleTreeError>;
+    fn delete(&mut self, index: usize) -> Result<(), ZerokitMerkleTreeError>;
+    fn proof(&self, index: usize) -> Result<Self::Proof, ZerokitMerkleTreeError>;
+    fn verify(
+        &self,
+        leaf: &FrOf<Self::Hasher>,
+        witness: &Self::Proof,
+    ) -> Result<bool, ZerokitMerkleTreeError>;
+    fn set_metadata(&mut self, metadata: &[u8]) -> Result<(), ZerokitMerkleTreeError>;
+    fn metadata(&self) -> Result<Vec<u8>, ZerokitMerkleTreeError>;
+    fn close_db_connection(&mut self) -> Result<(), ZerokitMerkleTreeError>;
 }
 
 pub trait ZerokitMerkleProof {

utils/src/merkle_tree/mod.rs

@@ -1,7 +1,11 @@
+pub mod error;
 pub mod full_merkle_tree;
 #[allow(clippy::module_inception)]
 pub mod merkle_tree;
 pub mod optimal_merkle_tree;
-pub use self::full_merkle_tree::*;
-pub use self::merkle_tree::*;
-pub use self::optimal_merkle_tree::*;
+
+pub use self::full_merkle_tree::{FullMerkleConfig, FullMerkleProof, FullMerkleTree};
+pub use self::merkle_tree::{
+    FrOf, Hasher, ZerokitMerkleProof, ZerokitMerkleTree, MIN_PARALLEL_NODES,
+};
+pub use self::optimal_merkle_tree::{OptimalMerkleConfig, OptimalMerkleProof, OptimalMerkleTree};

utils/src/merkle_tree/optimal_merkle_tree.rs

@@ -1,12 +1,13 @@
-use crate::merkle_tree::{Hasher, ZerokitMerkleProof, ZerokitMerkleTree};
-use crate::FrOf;
-use color_eyre::{Report, Result};
-use std::collections::HashMap;
-use std::str::FromStr;
-use std::{cmp::max, fmt::Debug};
+use std::{cmp::max, collections::HashMap, fmt::Debug, str::FromStr};
 
+use rayon::iter::{IntoParallelIterator, ParallelIterator};
+
+use crate::merkle_tree::{
+    error::{FromConfigError, ZerokitMerkleTreeError},
+    FrOf, Hasher, ZerokitMerkleProof, ZerokitMerkleTree, MIN_PARALLEL_NODES,
+};
 ////////////////////////////////////////////////////////////
-/// Optimal Merkle Tree Implementation
+///// Optimal Merkle Tree Implementation
 ////////////////////////////////////////////////////////////
 
 /// The Merkle tree structure
@@ -31,11 +32,11 @@ where
     /// Set to 0 if the leaf is empty and set to 1 in otherwise.
     cached_leaves_indices: Vec<u8>,
 
-    // The next available (i.e., never used) tree index. Equivalently, the number of leaves added to the tree
-    // (deletions leave next_index unchanged)
+    /// The next available (i.e., never used) tree index. Equivalently, the number of leaves added to the tree
+    /// (deletions leave next_index unchanged)
     next_index: usize,
 
-    // metadata that an application may use to store additional information
+    /// metadata that an application may use to store additional information
     metadata: Vec<u8>,
 }
 
@@ -48,15 +49,14 @@ pub struct OptimalMerkleProof<H: Hasher>(pub Vec<(H::Fr, u8)>);
 pub struct OptimalMerkleConfig(());
 
 impl FromStr for OptimalMerkleConfig {
-    type Err = Report;
+    type Err = FromConfigError;
 
-    fn from_str(_s: &str) -> Result<Self> {
+    fn from_str(_s: &str) -> Result<Self, Self::Err> {
         Ok(OptimalMerkleConfig::default())
     }
 }
 
 /// Implementations
-
 impl<H: Hasher> ZerokitMerkleTree for OptimalMerkleTree<H>
 where
     H: Hasher,
@@ -65,60 +65,86 @@ where
     type Hasher = H;
     type Config = OptimalMerkleConfig;
 
-    fn default(depth: usize) -> Result<Self> {
+    fn default(depth: usize) -> Result<Self, ZerokitMerkleTreeError> {
         OptimalMerkleTree::<H>::new(depth, H::default_leaf(), Self::Config::default())
     }
 
     /// Creates a new `MerkleTree`
     /// depth - the height of the tree made only of hash nodes. 2^depth is the maximum number of leaves hash nodes
-    fn new(depth: usize, default_leaf: H::Fr, _config: Self::Config) -> Result<Self> {
+    fn new(
+        depth: usize,
+        default_leaf: H::Fr,
+        _config: Self::Config,
+    ) -> Result<Self, ZerokitMerkleTreeError> {
+        // Compute cache node values, leaf to root
         let mut cached_nodes: Vec<H::Fr> = Vec::with_capacity(depth + 1);
         cached_nodes.push(default_leaf);
         for i in 0..depth {
             cached_nodes.push(H::hash(&[cached_nodes[i]; 2]));
         }
         cached_nodes.reverse();
+
         Ok(OptimalMerkleTree {
-            cached_nodes: cached_nodes.clone(),
             depth,
-            nodes: HashMap::new(),
+            cached_nodes,
+            nodes: HashMap::with_capacity(1 << depth),
             cached_leaves_indices: vec![0; 1 << depth],
             next_index: 0,
             metadata: Vec::new(),
         })
     }
 
-    fn close_db_connection(&mut self) -> Result<()> {
+    fn close_db_connection(&mut self) -> Result<(), ZerokitMerkleTreeError> {
         Ok(())
     }
 
-    // Returns the depth of the tree
+    /// Returns the depth of the tree
     fn depth(&self) -> usize {
         self.depth
     }
 
-    // Returns the capacity of the tree, i.e. the maximum number of accumulatable leaves
+    /// Returns the capacity of the tree, i.e. the maximum number of accumulatable leaves
     fn capacity(&self) -> usize {
         1 << self.depth
     }
 
-    // Returns the total number of leaves set
+    /// Returns the total number of leaves set
     fn leaves_set(&self) -> usize {
         self.next_index
     }
 
-    #[must_use]
-    // Returns the root of the tree
+    /// Returns the root of the tree
     fn root(&self) -> H::Fr {
         self.get_node(0, 0)
     }
 
-    fn get_subtree_root(&self, n: usize, index: usize) -> Result<H::Fr> {
+    /// Sets a leaf at the specified tree index
+    fn set(&mut self, index: usize, leaf: H::Fr) -> Result<(), ZerokitMerkleTreeError> {
+        if index >= self.capacity() {
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
+        }
+        self.nodes.insert((self.depth, index), leaf);
+        self.update_hashes(index, 1)?;
+        self.next_index = max(self.next_index, index + 1);
+        self.cached_leaves_indices[index] = 1;
+        Ok(())
+    }
+
+    /// Get a leaf from the specified tree index
+    fn get(&self, index: usize) -> Result<H::Fr, ZerokitMerkleTreeError> {
+        if index >= self.capacity() {
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
+        }
+        Ok(self.get_node(self.depth, index))
+    }
+
+    /// Returns the root of the subtree at level n and index
+    fn get_subtree_root(&self, n: usize, index: usize) -> Result<H::Fr, ZerokitMerkleTreeError> {
         if n > self.depth() {
-            return Err(Report::msg("level exceeds depth size"));
+            return Err(ZerokitMerkleTreeError::InvalidLevel);
         }
         if index >= self.capacity() {
-            return Err(Report::msg("index exceeds set size"));
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
         }
         if n == 0 {
             Ok(self.root())
@@ -129,26 +155,7 @@ where
         }
     }
 
-    // Sets a leaf at the specified tree index
-    fn set(&mut self, index: usize, leaf: H::Fr) -> Result<()> {
-        if index >= self.capacity() {
-            return Err(Report::msg("index exceeds set size"));
-        }
-        self.nodes.insert((self.depth, index), leaf);
-        self.recalculate_from(index)?;
-        self.next_index = max(self.next_index, index + 1);
-        self.cached_leaves_indices[index] = 1;
-        Ok(())
-    }
-
-    // Get a leaf from the specified tree index
-    fn get(&self, index: usize) -> Result<H::Fr> {
-        if index >= self.capacity() {
-            return Err(Report::msg("index exceeds set size"));
-        }
-        Ok(self.get_node(self.depth, index))
-    }
-
+    /// Returns the indices of the leaves that are empty
     fn get_empty_leaves_indices(&self) -> Vec<usize> {
         self.cached_leaves_indices
             .iter()
@@ -159,29 +166,39 @@ where
             .collect()
     }
 
-    // Sets multiple leaves from the specified tree index
-    fn set_range<I: IntoIterator<Item = H::Fr>>(&mut self, start: usize, leaves: I) -> Result<()> {
-        let leaves = leaves.into_iter().collect::<Vec<_>>();
+    /// Sets multiple leaves from the specified tree index
+    fn set_range<I: ExactSizeIterator<Item = H::Fr>>(
+        &mut self,
+        start: usize,
+        leaves: I,
+    ) -> Result<(), ZerokitMerkleTreeError> {
         // check if the range is valid
-        if start + leaves.len() > self.capacity() {
-            return Err(Report::msg("provided range exceeds set size"));
+        let leaves_len = leaves.len();
+        if start + leaves_len > self.capacity() {
+            return Err(ZerokitMerkleTreeError::TooManySet);
         }
-        for (i, leaf) in leaves.iter().enumerate() {
-            self.nodes.insert((self.depth, start + i), *leaf);
+        for (i, leaf) in leaves.enumerate() {
+            self.nodes.insert((self.depth, start + i), leaf);
             self.cached_leaves_indices[start + i] = 1;
-            self.recalculate_from(start + i)?;
         }
-        self.next_index = max(self.next_index, start + leaves.len());
+        self.update_hashes(start, leaves_len)?;
+        self.next_index = max(self.next_index, start + leaves_len);
         Ok(())
     }
 
-    fn override_range<I, J>(&mut self, start: usize, leaves: I, indices: J) -> Result<()>
+    /// Overrides a range of leaves while resetting specified indices to default and preserving unaffected values.
+    fn override_range<I, J>(
+        &mut self,
+        start: usize,
+        leaves: I,
+        indices: J,
+    ) -> Result<(), ZerokitMerkleTreeError>
     where
-        I: IntoIterator<Item = FrOf<Self::Hasher>>,
-        J: IntoIterator<Item = usize>,
+        I: ExactSizeIterator<Item = FrOf<Self::Hasher>>,
+        J: ExactSizeIterator<Item = usize>,
     {
         let indices = indices.into_iter().collect::<Vec<_>>();
-        let min_index = *indices.first().unwrap();
+        let min_index = *indices.first().expect("indices should not be empty");
         let leaves_vec = leaves.into_iter().collect::<Vec<_>>();
 
         let max_index = start + leaves_vec.len();
@@ -190,7 +207,7 @@ where
 
         for i in min_index..start {
             if !indices.contains(&i) {
-                let value = self.get_leaf(i);
+                let value = self.get(i)?;
                 set_values[i - min_index] = value;
             }
         }
@@ -203,18 +220,17 @@ where
             self.cached_leaves_indices[i] = 0;
         }
 
-        self.set_range(start, set_values)
-            .map_err(|e| Report::msg(e.to_string()))
+        self.set_range(start, set_values.into_iter())
     }
 
-    // Sets a leaf at the next available index
-    fn update_next(&mut self, leaf: H::Fr) -> Result<()> {
+    /// Sets a leaf at the next available index
+    fn update_next(&mut self, leaf: H::Fr) -> Result<(), ZerokitMerkleTreeError> {
         self.set(self.next_index, leaf)?;
         Ok(())
     }
 
-    // Deletes a leaf at a certain index by setting it to its default value (next_index is not updated)
-    fn delete(&mut self, index: usize) -> Result<()> {
+    /// Deletes a leaf at a certain index by setting it to its default value (next_index is not updated)
+    fn delete(&mut self, index: usize) -> Result<(), ZerokitMerkleTreeError> {
         // We reset the leaf only if we previously set a leaf at that index
         if index < self.next_index {
             self.set(index, H::default_leaf())?;
@@ -223,17 +239,20 @@ where
         Ok(())
     }
 
-    // Computes a merkle proof the the leaf at the specified index
-    fn proof(&self, index: usize) -> Result<Self::Proof> {
+    /// Computes a merkle proof the leaf at the specified index
+    fn proof(&self, index: usize) -> Result<Self::Proof, ZerokitMerkleTreeError> {
         if index >= self.capacity() {
-            return Err(Report::msg("index exceeds set size"));
+            return Err(ZerokitMerkleTreeError::InvalidLeaf);
         }
         let mut witness = Vec::<(H::Fr, u8)>::with_capacity(self.depth);
         let mut i = index;
         let mut depth = self.depth;
         loop {
             i ^= 1;
-            witness.push((self.get_node(depth, i), (1 - (i & 1)).try_into().unwrap()));
+            witness.push((
+                self.get_node(depth, i),
+                (1 - (i & 1)).try_into().expect("0 or 1 expected"),
+            ));
             i >>= 1;
             depth -= 1;
             if depth == 0 {
@@ -241,78 +260,102 @@ where
             }
         }
         if i != 0 {
-            Err(Report::msg("i != 0"))
+            Err(ZerokitMerkleTreeError::ComputingProofError)
         } else {
             Ok(OptimalMerkleProof(witness))
         }
     }
 
-    // Verifies a Merkle proof with respect to the input leaf and the tree root
-    fn verify(&self, leaf: &H::Fr, witness: &Self::Proof) -> Result<bool> {
+    /// Verifies a Merkle proof with respect to the input leaf and the tree root
+    fn verify(&self, leaf: &H::Fr, witness: &Self::Proof) -> Result<bool, ZerokitMerkleTreeError> {
         if witness.length() != self.depth {
-            return Err(Report::msg("witness length doesn't match tree depth"));
+            return Err(ZerokitMerkleTreeError::InvalidWitness);
         }
         let expected_root = witness.compute_root_from(leaf);
         Ok(expected_root.eq(&self.root()))
     }
 
-    fn compute_root(&mut self) -> Result<FrOf<Self::Hasher>> {
-        self.recalculate_from(0)?;
-        Ok(self.root())
-    }
-
-    fn set_metadata(&mut self, metadata: &[u8]) -> Result<()> {
+    fn set_metadata(&mut self, metadata: &[u8]) -> Result<(), ZerokitMerkleTreeError> {
         self.metadata = metadata.to_vec();
         Ok(())
     }
 
-    fn metadata(&self) -> Result<Vec<u8>> {
+    fn metadata(&self) -> Result<Vec<u8>, ZerokitMerkleTreeError> {
         Ok(self.metadata.to_vec())
     }
 }
 
+// Utilities for updating the tree nodes
 impl<H: Hasher> OptimalMerkleTree<H>
 where
     H: Hasher,
 {
-    // Utilities for updating the tree nodes
-
+    /// Returns the value of a node at a specific (depth, index).
+    /// Falls back to a cached default if the node hasn't been set.
     fn get_node(&self, depth: usize, index: usize) -> H::Fr {
-        let node = *self
+        *self
             .nodes
             .get(&(depth, index))
-            .unwrap_or_else(|| &self.cached_nodes[depth]);
-        node
+            .unwrap_or_else(|| &self.cached_nodes[depth])
     }
 
-    pub fn get_leaf(&self, index: usize) -> H::Fr {
-        self.get_node(self.depth, index)
-    }
-
-    fn hash_couple(&mut self, depth: usize, index: usize) -> H::Fr {
+    /// Computes the hash of a node’s two children at the given depth.
+    /// If the index is odd, it is rounded down to the nearest even index.
+    fn hash_couple(&self, depth: usize, index: usize) -> H::Fr {
         let b = index & !1;
         H::hash(&[self.get_node(depth, b), self.get_node(depth, b + 1)])
     }
 
-    fn recalculate_from(&mut self, index: usize) -> Result<()> {
-        let mut i = index;
-        let mut depth = self.depth;
-        loop {
-            let h = self.hash_couple(depth, i);
-            i >>= 1;
-            depth -= 1;
-            self.nodes.insert((depth, i), h);
-            self.cached_leaves_indices[index] = 1;
-            if depth == 0 {
-                break;
+    /// Updates parent hashes after modifying a range of leaf nodes.
+    ///
+    /// - `start`: Starting leaf index that was updated.
+    /// - `length`: Number of consecutive leaves that were updated.
+    fn update_hashes(&mut self, start: usize, length: usize) -> Result<(), ZerokitMerkleTreeError> {
+        // Start at the leaf level
+        let mut current_depth = self.depth;
+
+        // Round down to include the left sibling in the pair (if start is odd)
+        let mut current_index = start & !1;
+
+        // Compute the max index at this level, round up to include the last updated leaf’s right sibling (if start + length is odd)
+        let mut current_index_max = (start + length + 1) & !1;
+
+        // Traverse from the leaf level up to the root
+        while current_depth > 0 {
+            // Compute the parent level (one level above the current)
+            let parent_depth = current_depth - 1;
+
+            // Use parallel processing when the number of pairs exceeds the threshold
+            if current_index_max - current_index >= MIN_PARALLEL_NODES {
+                let updates: Vec<((usize, usize), H::Fr)> = (current_index..current_index_max)
+                    .step_by(2)
+                    .collect::<Vec<_>>()
+                    .into_par_iter()
+                    .map(|index| {
+                        // Hash two child nodes at positions (current_depth, index) and (current_depth, index + 1)
+                        let hash = self.hash_couple(current_depth, index);
+                        // Return the computed parent hash and its position at
+                        ((parent_depth, index >> 1), hash)
+                    })
+                    .collect();
+
+                for (parent, hash) in updates {
+                    self.nodes.insert(parent, hash);
+                }
+            } else {
+                // Otherwise, fallback to sequential update for small ranges
+                for index in (current_index..current_index_max).step_by(2) {
+                    let hash = self.hash_couple(current_depth, index);
+                    self.nodes.insert((parent_depth, index >> 1), hash);
+                }
             }
+
+            // Move up one level in the tree
+            current_index >>= 1;
+            current_index_max = (current_index_max + 1) >> 1;
+            current_depth -= 1;
         }
-        if depth != 0 {
-            return Err(Report::msg("did not reach the depth"));
-        }
-        if i != 0 {
-            return Err(Report::msg("did not go through all indexes"));
-        }
+
         Ok(())
     }
 }
@@ -324,14 +367,12 @@ where
     type Index = u8;
     type Hasher = H;
 
-    #[must_use]
-    // Returns the length of a Merkle proof
+    /// Returns the length of a Merkle proof
     fn length(&self) -> usize {
         self.0.len()
     }
 
     /// Computes the leaf index corresponding to a Merkle proof
-    #[must_use]
     fn leaf_index(&self) -> usize {
         // In current implementation the path indexes in a proof correspond to the binary representation of the leaf index
         let mut binary_repr = self.get_path_index();
@@ -341,19 +382,16 @@ where
             .fold(0, |acc, digit| (acc << 1) + usize::from(digit))
     }
 
-    #[must_use]
     /// Returns the path elements forming a Merkle proof
     fn get_path_elements(&self) -> Vec<H::Fr> {
         self.0.iter().map(|x| x.0).collect()
     }
 
     /// Returns the path indexes forming a Merkle proof
-    #[must_use]
     fn get_path_index(&self) -> Vec<u8> {
         self.0.iter().map(|x| x.1).collect()
     }
 
-    #[must_use]
     /// Computes the Merkle root corresponding by iteratively hashing a Merkle proof with a given input leaf
     fn compute_root_from(&self, leaf: &H::Fr) -> H::Fr {
         let mut acc: H::Fr = *leaf;

utils/src/pm_tree/mod.rs

@@ -1,4 +1,4 @@
 pub mod sled_adapter;
-pub use self::sled_adapter::*;
+pub use self::sled_adapter::SledDB;
 pub use pmtree;
-pub use sled::*;
+pub use sled::{Config, Mode};

utils/src/poseidon/mod.rs

@@ -1,5 +1,4 @@
 pub mod poseidon_hash;
-pub use self::poseidon_hash::*;
+pub use poseidon_hash::Poseidon;
 
 pub mod poseidon_constants;
-pub use self::poseidon_constants::*;

utils/src/poseidon/poseidon_constants.rs

@@ -9,8 +9,6 @@
 
 // The following implementation was adapted from https://github.com/arkworks-rs/sponge/blob/7d9b3a474c9ddb62890014aeaefcb142ac2b3776/src/poseidon/grain_lfsr.rs
 
-#![allow(dead_code)]
-
 use ark_ff::PrimeField;
 use num_bigint::BigUint;
 
@@ -20,7 +18,6 @@ pub struct PoseidonGrainLFSR {
     pub head: usize,
 }
 
-#[allow(unused_variables)]
 impl PoseidonGrainLFSR {
     pub fn new(
         is_field: u64,

utils/src/poseidon/poseidon_hash.rs

@@ -7,7 +7,7 @@ use crate::poseidon_constants::find_poseidon_ark_and_mds;
 use ark_ff::PrimeField;
 
 #[derive(Debug, Clone, PartialEq, Eq)]
-pub struct RoundParamenters<F: PrimeField> {
+pub struct RoundParameters<F: PrimeField> {
     pub t: usize,
     pub n_rounds_f: usize,
     pub n_rounds_p: usize,
@@ -17,16 +17,16 @@ pub struct RoundParamenters<F: PrimeField> {
 }
 
 pub struct Poseidon<F: PrimeField> {
-    round_params: Vec<RoundParamenters<F>>,
+    round_params: Vec<RoundParameters<F>>,
 }
 impl<F: PrimeField> Poseidon<F> {
     // Loads round parameters and generates round constants
     // poseidon_params is a vector containing tuples (t, RF, RP, skip_matrices)
-    // where: t is the rate (input lenght + 1), RF is the number of full rounds, RP is the number of partial rounds
+    // where: t is the rate (input length + 1), RF is the number of full rounds, RP is the number of partial rounds
     // and skip_matrices is a (temporary) parameter used to generate secure MDS matrices (see comments in the description of find_poseidon_ark_and_mds)
     // TODO: implement automatic generation of round parameters
     pub fn from(poseidon_params: &[(usize, usize, usize, usize)]) -> Self {
-        let mut read_params = Vec::<RoundParamenters<F>>::new();
+        let mut read_params = Vec::<RoundParameters<F>>::with_capacity(poseidon_params.len());
 
         for &(t, n_rounds_f, n_rounds_p, skip_matrices) in poseidon_params {
             let (ark, mds) = find_poseidon_ark_and_mds::<F>(
@@ -38,7 +38,7 @@ impl<F: PrimeField> Poseidon<F> {
                 n_rounds_p as u64,
                 skip_matrices,
             );
-            let rp = RoundParamenters {
+            let rp = RoundParameters {
                 t,
                 n_rounds_p,
                 n_rounds_f,
@@ -54,24 +54,24 @@ impl<F: PrimeField> Poseidon<F> {
         }
     }
 
-    pub fn get_parameters(&self) -> Vec<RoundParamenters<F>> {
-        self.round_params.clone()
+    pub fn get_parameters(&self) -> &Vec<RoundParameters<F>> {
+        &self.round_params
     }
 
     pub fn ark(&self, state: &mut [F], c: &[F], it: usize) {
-        for i in 0..state.len() {
-            state[i] += c[it + i];
-        }
+        state.iter_mut().enumerate().for_each(|(i, elem)| {
+            *elem += c[it + i];
+        });
     }
 
     pub fn sbox(&self, n_rounds_f: usize, n_rounds_p: usize, state: &mut [F], i: usize) {
         if (i < n_rounds_f / 2) || (i >= n_rounds_f / 2 + n_rounds_p) {
-            for current_state in &mut state.iter_mut() {
+            state.iter_mut().for_each(|current_state| {
                 let aux = *current_state;
                 *current_state *= *current_state;
                 *current_state *= *current_state;
                 *current_state *= aux;
-            }
+            })
         } else {
             let aux = state[0];
             state[0] *= state[0];
@@ -80,21 +80,20 @@ impl<F: PrimeField> Poseidon<F> {
         }
     }
 
-    pub fn mix(&self, state: &[F], m: &[Vec<F>]) -> Vec<F> {
-        let mut new_state: Vec<F> = Vec::new();
+    pub fn mix_2(&self, state: &[F], m: &[Vec<F>], state_2: &mut [F]) {
         for i in 0..state.len() {
-            new_state.push(F::zero());
-            for (j, state_item) in state.iter().enumerate() {
-                let mut mij = m[i][j];
-                mij *= state_item;
-                new_state[i] += mij;
+            // Cache the row reference
+            let row = &m[i];
+            let mut acc = F::ZERO;
+            for j in 0..state.len() {
+                acc += row[j] * state[j];
             }
+            state_2[i] = acc;
         }
-        new_state.clone()
     }
 
-    pub fn hash(&self, inp: Vec<F>) -> Result<F, String> {
-        // Note that the rate t becomes input lenght + 1, hence for lenght N we pick parameters with T = N + 1
+    pub fn hash(&self, inp: &[F]) -> Result<F, String> {
+        // Note that the rate t becomes input length + 1; hence for length N we pick parameters with T = N + 1
         let t = inp.len() + 1;
 
         // We seek the index (Poseidon's round_params is an ordered vector) for the parameters corresponding to t
@@ -106,8 +105,9 @@ impl<F: PrimeField> Poseidon<F> {
 
         let param_index = param_index.unwrap();
 
-        let mut state = vec![F::zero(); t];
-        state[1..].clone_from_slice(&inp);
+        let mut state = vec![F::ZERO; t];
+        let mut state_2 = state.clone();
+        state[1..].clone_from_slice(inp);
 
         for i in 0..(self.round_params[param_index].n_rounds_f
             + self.round_params[param_index].n_rounds_p)
@@ -123,7 +123,8 @@ impl<F: PrimeField> Poseidon<F> {
                 &mut state,
                 i,
             );
-            state = self.mix(&state, &self.round_params[param_index].m);
+            self.mix_2(&state, &self.round_params[param_index].m, &mut state_2);
+            std::mem::swap(&mut state, &mut state_2);
         }
 
         Ok(state[0])

utils/tests/merkle_tree.rs

@@ -6,7 +6,7 @@ pub mod test {
     use tiny_keccak::{Hasher as _, Keccak};
     use zerokit_utils::{
         FullMerkleConfig, FullMerkleTree, Hasher, OptimalMerkleConfig, OptimalMerkleTree,
-        ZerokitMerkleProof, ZerokitMerkleTree,
+        ZerokitMerkleProof, ZerokitMerkleTree, MIN_PARALLEL_NODES,
     };
     #[derive(Clone, Copy, Eq, PartialEq)]
     struct Keccak256;
@@ -42,7 +42,7 @@ pub mod test {
         type Err = std::string::FromUtf8Error;
 
         fn from_str(s: &str) -> Result<Self, Self::Err> {
-            Ok(TestFr(s.as_bytes().try_into().unwrap()))
+            Ok(TestFr(s.as_bytes().try_into().expect("Invalid length")))
         }
     }
 
@@ -50,7 +50,7 @@ pub mod test {
         fn from(value: u32) -> Self {
             let mut bytes: Vec<u8> = vec![0; 28];
             bytes.extend_from_slice(&value.to_be_bytes());
-            TestFr(bytes.as_slice().try_into().unwrap())
+            TestFr(bytes.as_slice().try_into().expect("Invalid length"))
         }
     }
 
@@ -58,12 +58,12 @@ pub mod test {
 
     fn default_full_merkle_tree(depth: usize) -> FullMerkleTree<Keccak256> {
         FullMerkleTree::<Keccak256>::new(depth, TestFr([0; 32]), FullMerkleConfig::default())
-            .unwrap()
+            .expect("Failed to create FullMerkleTree")
     }
 
     fn default_optimal_merkle_tree(depth: usize) -> OptimalMerkleTree<Keccak256> {
         OptimalMerkleTree::<Keccak256>::new(depth, TestFr([0; 32]), OptimalMerkleConfig::default())
-            .unwrap()
+            .expect("Failed to create OptimalMerkleTree")
     }
 
     #[test]
@@ -83,21 +83,101 @@ pub mod test {
         let nof_leaves = 4;
         let leaves: Vec<TestFr> = (1..=nof_leaves as u32).map(TestFr::from).collect();
 
-        let mut tree = default_full_merkle_tree(DEFAULT_DEPTH);
-        assert_eq!(tree.root(), default_tree_root);
+        let mut tree_full = default_full_merkle_tree(DEFAULT_DEPTH);
+        assert_eq!(tree_full.root(), default_tree_root);
         for i in 0..nof_leaves {
-            tree.set(i, leaves[i]).unwrap();
-            assert_eq!(tree.root(), roots[i]);
+            tree_full.set(i, leaves[i]).expect("Failed to set leaf");
+            assert_eq!(tree_full.root(), roots[i]);
         }
 
-        let mut tree = default_optimal_merkle_tree(DEFAULT_DEPTH);
-        assert_eq!(tree.root(), default_tree_root);
+        let mut tree_opt = default_optimal_merkle_tree(DEFAULT_DEPTH);
+        assert_eq!(tree_opt.root(), default_tree_root);
         for i in 0..nof_leaves {
-            tree.set(i, leaves[i]).unwrap();
-            assert_eq!(tree.root(), roots[i]);
+            tree_opt.set(i, leaves[i]).expect("Failed to set leaf");
+            assert_eq!(tree_opt.root(), roots[i]);
         }
     }
 
+    #[test]
+    fn test_set_range() {
+        let depth = 4;
+        let leaves: Vec<TestFr> = (0..(1 << depth) as u32).map(TestFr::from).collect();
+
+        let mut tree_full = default_full_merkle_tree(depth);
+        let root_before = tree_full.root();
+        tree_full
+            .set_range(0, leaves.iter().cloned())
+            .expect("Failed to set leaves");
+        let root_after = tree_full.root();
+        assert_ne!(root_before, root_after);
+
+        let mut tree_opt = default_optimal_merkle_tree(depth);
+        let root_before = tree_opt.root();
+        tree_opt
+            .set_range(0, leaves.iter().cloned())
+            .expect("Failed to set leaves");
+        let root_after = tree_opt.root();
+        assert_ne!(root_before, root_after);
+    }
+
+    #[test]
+    fn test_update_next() {
+        let mut tree_full = default_full_merkle_tree(DEFAULT_DEPTH);
+        let mut tree_opt = default_optimal_merkle_tree(DEFAULT_DEPTH);
+
+        for i in 0..4 {
+            let leaf = TestFr::from(i as u32);
+            tree_full.update_next(leaf).expect("Failed to update leaf");
+            tree_opt.update_next(leaf).expect("Failed to update leaf");
+            assert_eq!(tree_full.get(i).expect("Failed to get leaf"), leaf);
+            assert_eq!(tree_opt.get(i).expect("Failed to get leaf"), leaf);
+        }
+
+        assert_eq!(tree_full.leaves_set(), 4);
+        assert_eq!(tree_opt.leaves_set(), 4);
+    }
+
+    #[test]
+    fn test_delete_and_reset() {
+        let index = 1;
+        let original_leaf = TestFr::from(42);
+        let new_leaf = TestFr::from(99);
+
+        let mut tree_full = default_full_merkle_tree(DEFAULT_DEPTH);
+        tree_full
+            .set(index, original_leaf)
+            .expect("Failed to set leaf");
+        let root_with_original = tree_full.root();
+
+        tree_full.delete(index).expect("Failed to delete leaf");
+        let root_after_delete = tree_full.root();
+        assert_ne!(root_with_original, root_after_delete);
+
+        tree_full.set(index, new_leaf).expect("Failed to set leaf");
+        let root_after_reset = tree_full.root();
+
+        assert_ne!(root_after_delete, root_after_reset);
+        assert_ne!(root_with_original, root_after_reset);
+        assert_eq!(tree_full.get(index).expect("Failed to get leaf"), new_leaf);
+
+        let mut tree_opt = default_optimal_merkle_tree(DEFAULT_DEPTH);
+        tree_opt
+            .set(index, original_leaf)
+            .expect("Failed to set leaf");
+        let root_with_original = tree_opt.root();
+
+        tree_opt.delete(index).expect("Failed to delete leaf");
+        let root_after_delete = tree_opt.root();
+        assert_ne!(root_with_original, root_after_delete);
+
+        tree_opt.set(index, new_leaf).expect("Failed to set leaf");
+        let root_after_reset = tree_opt.root();
+
+        assert_ne!(root_after_delete, root_after_reset);
+        assert_ne!(root_with_original, root_after_reset);
+        assert_eq!(tree_opt.get(index).expect("Failed to get leaf"), new_leaf);
+    }
+
     #[test]
     fn test_get_empty_leaves_indices() {
         let depth = 4;
@@ -107,7 +187,7 @@ pub mod test {
         let leaves_4: Vec<TestFr> = (0u32..4).map(TestFr::from).collect();
 
         let mut tree_full = default_full_merkle_tree(depth);
-        let _ = tree_full.set_range(0, leaves.clone());
+        let _ = tree_full.set_range(0, leaves.clone().into_iter());
         assert!(tree_full.get_empty_leaves_indices().is_empty());
 
         let mut vec_idxs = Vec::new();
@@ -123,33 +203,31 @@ pub mod test {
             assert_eq!(tree_full.get_empty_leaves_indices(), vec_idxs);
         }
 
-        // Check situation when the number of items to insert is less than the number of items to delete
+        // check situation when the number of items to insert is less than the number of items to delete
         tree_full
-            .override_range(0, leaves_2.clone(), [0, 1, 2, 3])
-            .unwrap();
+            .override_range(0, leaves_2.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .expect("Failed to override range");
 
         // check if the indexes for write and delete are the same
         tree_full
-            .override_range(0, leaves_4.clone(), [0, 1, 2, 3])
-            .unwrap();
-        assert_eq!(tree_full.get_empty_leaves_indices(), vec![]);
+            .override_range(0, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .expect("Failed to override range");
+        assert_eq!(tree_full.get_empty_leaves_indices(), Vec::<usize>::new());
 
         // check if indexes for deletion are before indexes for overwriting
         tree_full
-            .override_range(4, leaves_4.clone(), [0, 1, 2, 3])
-            .unwrap();
+            .override_range(4, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .expect("Failed to override range");
         assert_eq!(tree_full.get_empty_leaves_indices(), vec![0, 1, 2, 3]);
 
         // check if the indices for write and delete do not overlap completely
         tree_full
-            .override_range(2, leaves_4.clone(), [0, 1, 2, 3])
-            .unwrap();
+            .override_range(2, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .expect("Failed to override range");
         assert_eq!(tree_full.get_empty_leaves_indices(), vec![0, 1]);
 
-        //// Optimal Merkle Tree Trest
-
         let mut tree_opt = default_optimal_merkle_tree(depth);
-        let _ = tree_opt.set_range(0, leaves.clone());
+        let _ = tree_opt.set_range(0, leaves.clone().into_iter());
         assert!(tree_opt.get_empty_leaves_indices().is_empty());
 
         let mut vec_idxs = Vec::new();
@@ -164,48 +242,55 @@ pub mod test {
             assert_eq!(tree_opt.get_empty_leaves_indices(), vec_idxs);
         }
 
-        // Check situation when the number of items to insert is less than the number of items to delete
+        // check situation when the number of items to insert is less than the number of items to delete
         tree_opt
-            .override_range(0, leaves_2.clone(), [0, 1, 2, 3])
-            .unwrap();
+            .override_range(0, leaves_2.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .expect("Failed to override range");
 
         // check if the indexes for write and delete are the same
         tree_opt
-            .override_range(0, leaves_4.clone(), [0, 1, 2, 3])
-            .unwrap();
-        assert_eq!(tree_opt.get_empty_leaves_indices(), vec![]);
+            .override_range(0, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .expect("Failed to override range");
+        assert_eq!(tree_opt.get_empty_leaves_indices(), Vec::<usize>::new());
 
         // check if indexes for deletion are before indexes for overwriting
         tree_opt
-            .override_range(4, leaves_4.clone(), [0, 1, 2, 3])
-            .unwrap();
+            .override_range(4, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .expect("Failed to override range");
         assert_eq!(tree_opt.get_empty_leaves_indices(), vec![0, 1, 2, 3]);
 
         // check if the indices for write and delete do not overlap completely
         tree_opt
-            .override_range(2, leaves_4.clone(), [0, 1, 2, 3])
-            .unwrap();
+            .override_range(2, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .expect("Failed to override range");
         assert_eq!(tree_opt.get_empty_leaves_indices(), vec![0, 1]);
     }
 
     #[test]
     fn test_subtree_root() {
         let depth = 3;
-        let nof_leaves: usize = 6;
+        let nof_leaves: usize = 4;
         let leaves: Vec<TestFr> = (0..nof_leaves as u32).map(TestFr::from).collect();
 
-        let mut tree_full = default_optimal_merkle_tree(depth);
+        let mut tree_full = default_full_merkle_tree(depth);
         let _ = tree_full.set_range(0, leaves.iter().cloned());
 
         for i in 0..nof_leaves {
             // check leaves
             assert_eq!(
-                tree_full.get(i).unwrap(),
-                tree_full.get_subtree_root(depth, i).unwrap()
+                tree_full.get(i).expect("Failed to get leaf"),
+                tree_full
+                    .get_subtree_root(depth, i)
+                    .expect("Failed to get subtree root")
             );
 
             // check root
-            assert_eq!(tree_full.root(), tree_full.get_subtree_root(0, i).unwrap());
+            assert_eq!(
+                tree_full.root(),
+                tree_full
+                    .get_subtree_root(0, i)
+                    .expect("Failed to get subtree root")
+            );
         }
 
         // check intermediate nodes
@@ -215,26 +300,39 @@ pub mod test {
                 let idx_r = (i + 1) * (1 << (depth - n));
                 let idx_sr = idx_l;
 
-                let prev_l = tree_full.get_subtree_root(n, idx_l).unwrap();
-                let prev_r = tree_full.get_subtree_root(n, idx_r).unwrap();
-                let subroot = tree_full.get_subtree_root(n - 1, idx_sr).unwrap();
+                let prev_l = tree_full
+                    .get_subtree_root(n, idx_l)
+                    .expect("Failed to get subtree root");
+                let prev_r = tree_full
+                    .get_subtree_root(n, idx_r)
+                    .expect("Failed to get subtree root");
+                let subroot = tree_full
+                    .get_subtree_root(n - 1, idx_sr)
+                    .expect("Failed to get subtree root");
 
                 // check intermediate nodes
                 assert_eq!(Keccak256::hash(&[prev_l, prev_r]), subroot);
             }
         }
 
-        let mut tree_opt = default_full_merkle_tree(depth);
+        let mut tree_opt = default_optimal_merkle_tree(depth);
         let _ = tree_opt.set_range(0, leaves.iter().cloned());
 
         for i in 0..nof_leaves {
             // check leaves
             assert_eq!(
-                tree_opt.get(i).unwrap(),
-                tree_opt.get_subtree_root(depth, i).unwrap()
+                tree_opt.get(i).expect("Failed to get leaf"),
+                tree_opt
+                    .get_subtree_root(depth, i)
+                    .expect("Failed to get subtree root")
             );
             // check root
-            assert_eq!(tree_opt.root(), tree_opt.get_subtree_root(0, i).unwrap());
+            assert_eq!(
+                tree_opt.root(),
+                tree_opt
+                    .get_subtree_root(0, i)
+                    .expect("Failed to get subtree root")
+            );
         }
 
         // check intermediate nodes
@@ -244,9 +342,15 @@ pub mod test {
                 let idx_r = (i + 1) * (1 << (depth - n));
                 let idx_sr = idx_l;
 
-                let prev_l = tree_opt.get_subtree_root(n, idx_l).unwrap();
-                let prev_r = tree_opt.get_subtree_root(n, idx_r).unwrap();
-                let subroot = tree_opt.get_subtree_root(n - 1, idx_sr).unwrap();
+                let prev_l = tree_opt
+                    .get_subtree_root(n, idx_l)
+                    .expect("Failed to get subtree root");
+                let prev_r = tree_opt
+                    .get_subtree_root(n, idx_r)
+                    .expect("Failed to get subtree root");
+                let subroot = tree_opt
+                    .get_subtree_root(n - 1, idx_sr)
+                    .expect("Failed to get subtree root");
 
                 // check intermediate nodes
                 assert_eq!(Keccak256::hash(&[prev_l, prev_r]), subroot);
@@ -259,61 +363,83 @@ pub mod test {
         let nof_leaves = 4;
         let leaves: Vec<TestFr> = (0..nof_leaves as u32).map(TestFr::from).collect();
 
-        // We thest the FullMerkleTree implementation
-        let mut tree = default_full_merkle_tree(DEFAULT_DEPTH);
+        // We test the FullMerkleTree implementation
+        let mut tree_full = default_full_merkle_tree(DEFAULT_DEPTH);
         for i in 0..nof_leaves {
             // We set the leaves
-            tree.set(i, leaves[i]).unwrap();
+            tree_full.set(i, leaves[i]).expect("Failed to set leaf");
 
             // We compute a merkle proof
-            let proof = tree.proof(i).expect("index should be set");
+            let proof = tree_full.proof(i).expect("Failed to compute proof");
 
             // We verify if the merkle proof corresponds to the right leaf index
             assert_eq!(proof.leaf_index(), i);
 
             // We verify the proof
-            assert!(tree.verify(&leaves[i], &proof).unwrap());
+            assert!(tree_full
+                .verify(&leaves[i], &proof)
+                .expect("Failed to verify proof"));
 
             // We ensure that the Merkle proof and the leaf generate the same root as the tree
-            assert_eq!(proof.compute_root_from(&leaves[i]), tree.root());
+            assert_eq!(proof.compute_root_from(&leaves[i]), tree_full.root());
 
             // We check that the proof is not valid for another leaf
-            assert!(!tree.verify(&leaves[(i + 1) % nof_leaves], &proof).unwrap());
+            assert!(!tree_full
+                .verify(&leaves[(i + 1) % nof_leaves], &proof)
+                .expect("Failed to verify proof"));
         }
 
         // We test the OptimalMerkleTree implementation
-        let mut tree = default_optimal_merkle_tree(DEFAULT_DEPTH);
+        let mut tree_opt = default_optimal_merkle_tree(DEFAULT_DEPTH);
         for i in 0..nof_leaves {
             // We set the leaves
-            tree.set(i, leaves[i]).unwrap();
+            tree_opt.set(i, leaves[i]).expect("Failed to set leaf");
 
             // We compute a merkle proof
-            let proof = tree.proof(i).expect("index should be set");
+            let proof = tree_opt.proof(i).expect("Failed to compute proof");
 
             // We verify if the merkle proof corresponds to the right leaf index
             assert_eq!(proof.leaf_index(), i);
 
             // We verify the proof
-            assert!(tree.verify(&leaves[i], &proof).unwrap());
+            assert!(tree_opt
+                .verify(&leaves[i], &proof)
+                .expect("Failed to verify proof"));
 
             // We ensure that the Merkle proof and the leaf generate the same root as the tree
-            assert_eq!(proof.compute_root_from(&leaves[i]), tree.root());
+            assert_eq!(proof.compute_root_from(&leaves[i]), tree_opt.root());
 
             // We check that the proof is not valid for another leaf
-            assert!(!tree.verify(&leaves[(i + 1) % nof_leaves], &proof).unwrap());
+            assert!(!tree_opt
+                .verify(&leaves[(i + 1) % nof_leaves], &proof)
+                .expect("Failed to verify proof"));
         }
     }
 
+    #[test]
+    fn test_proof_fail() {
+        let tree_full = default_full_merkle_tree(DEFAULT_DEPTH);
+        let tree_opt = default_optimal_merkle_tree(DEFAULT_DEPTH);
+
+        let invalid_leaf = TestFr::from(12345);
+
+        let proof_full = tree_full.proof(0).expect("Failed to compute proof");
+        let proof_opt = tree_opt.proof(0).expect("Failed to compute proof");
+
+        // Should fail because no leaf was set
+        assert!(!tree_full
+            .verify(&invalid_leaf, &proof_full)
+            .expect("Failed to verify proof"));
+        assert!(!tree_opt
+            .verify(&invalid_leaf, &proof_opt)
+            .expect("Failed to verify proof"));
+    }
+
     #[test]
     fn test_override_range() {
         let nof_leaves = 4;
         let leaves: Vec<TestFr> = (0..nof_leaves as u32).map(TestFr::from).collect();
 
-        let mut tree = default_optimal_merkle_tree(DEFAULT_DEPTH);
-
-        // We set the leaves
-        tree.set_range(0, leaves.iter().cloned()).unwrap();
-
         let new_leaves = [
             hex!("0000000000000000000000000000000000000000000000000000000000000005"),
             hex!("0000000000000000000000000000000000000000000000000000000000000006"),
@@ -322,17 +448,70 @@ pub mod test {
 
         let to_delete_indices: [usize; 2] = [0, 1];
 
-        // We override the leaves
-        tree.override_range(
-            0, // start from the end of the initial leaves
-            new_leaves.iter().cloned(),
-            to_delete_indices.iter().cloned(),
-        )
-        .unwrap();
+        let mut tree_full = default_full_merkle_tree(DEFAULT_DEPTH);
+        tree_full
+            .set_range(0, leaves.iter().cloned())
+            .expect("Failed to set leaves");
+
+        tree_full
+            .override_range(
+                0,
+                new_leaves.iter().cloned(),
+                to_delete_indices.iter().cloned(),
+            )
+            .expect("Failed to override range");
 
-        // ensure that the leaves are set correctly
         for (i, &new_leaf) in new_leaves.iter().enumerate() {
-            assert_eq!(tree.get_leaf(i), new_leaf);
+            assert_eq!(tree_full.get(i).expect("Failed to get leaf"), new_leaf);
+        }
+
+        let mut tree_opt = default_optimal_merkle_tree(DEFAULT_DEPTH);
+        tree_opt
+            .set_range(0, leaves.iter().cloned())
+            .expect("Failed to set leaves");
+
+        tree_opt
+            .override_range(
+                0,
+                new_leaves.iter().cloned(),
+                to_delete_indices.iter().cloned(),
+            )
+            .expect("Failed to override range");
+
+        for (i, &new_leaf) in new_leaves.iter().enumerate() {
+            assert_eq!(tree_opt.get(i).expect("Failed to get leaf"), new_leaf);
+        }
+    }
+
+    #[test]
+    fn test_override_range_parallel_triggered() {
+        let depth = 13;
+        let nof_leaves = 8192;
+
+        // number of leaves larger than MIN_PARALLEL_NODES to trigger parallel hashing
+        assert!(MIN_PARALLEL_NODES < nof_leaves);
+
+        let leaves: Vec<TestFr> = (0..nof_leaves as u32).map(TestFr::from).collect();
+        let indices: Vec<usize> = (0..nof_leaves).collect();
+
+        let mut tree_full = default_full_merkle_tree(depth);
+
+        tree_full
+            .override_range(0, leaves.iter().cloned(), indices.iter().cloned())
+            .expect("Failed to override range");
+
+        for (i, &leaf) in leaves.iter().enumerate() {
+            assert_eq!(tree_full.get(i).expect("Failed to get leaf"), leaf);
+        }
+
+        let mut tree_opt = default_optimal_merkle_tree(depth);
+
+        tree_opt
+            .override_range(0, leaves.iter().cloned(), indices.iter().cloned())
+            .expect("Failed to override range");
+
+        for (i, &leaf) in leaves.iter().enumerate() {
+            assert_eq!(tree_opt.get(i).expect("Failed to get leaf"), leaf);
         }
     }
 }

utils/tests/poseidon_constants.rs

@@ -3530,7 +3530,8 @@ mod test {
         {
             // We check if the round constants and matrices correspond to the one generated when instantiating Poseidon with ROUND_PARAMS
             let (loaded_c, loaded_m) = load_constants();
-            let poseidon_parameters = Poseidon::<Fr>::from(&ROUND_PARAMS).get_parameters();
+            let poseidon_hasher = Poseidon::<Fr>::from(&ROUND_PARAMS);
+            let poseidon_parameters = poseidon_hasher.get_parameters();
             for i in 0..poseidon_parameters.len() {
                 assert_eq!(loaded_c[i], poseidon_parameters[i].c);
                 assert_eq!(loaded_m[i], poseidon_parameters[i].m);

utils/tests/poseidon_hash_test.rs

@@ -0,0 +1,131 @@
+#[cfg(test)]
+mod test {
+    use ark_bn254::Fr;
+    use ark_ff::{AdditiveGroup, Field};
+    use std::collections::HashMap;
+    use std::str::FromStr;
+    use zerokit_utils::poseidon_hash::Poseidon;
+
+    const ROUND_PARAMS: [(usize, usize, usize, usize); 8] = [
+        (2, 8, 56, 0),
+        (3, 8, 57, 0),
+        (4, 8, 56, 0),
+        (5, 8, 60, 0),
+        (6, 8, 60, 0),
+        (7, 8, 63, 0),
+        (8, 8, 64, 0),
+        (9, 8, 63, 0),
+    ];
+
+    #[test]
+    fn test_poseidon_hash_basic() {
+        let map = HashMap::from([
+            (
+                Fr::ZERO,
+                Fr::from_str(
+                    "19014214495641488759237505126948346942972912379615652741039992445865937985820",
+                )
+                .unwrap(),
+            ),
+            (
+                Fr::ONE,
+                Fr::from_str(
+                    "18586133768512220936620570745912940619677854269274689475585506675881198879027",
+                )
+                .unwrap(),
+            ),
+            (
+                Fr::from(255),
+                Fr::from_str(
+                    "20026131459732984724454933360292530547665726761019872861025481903072111625788",
+                )
+                .unwrap(),
+            ),
+            (
+                Fr::from(u16::MAX),
+                Fr::from_str(
+                    "12358868638722666642632413418981275677998688723398440898957566982787708451243",
+                )
+                .unwrap(),
+            ),
+            (
+                Fr::from(u64::MAX),
+                Fr::from_str(
+                    "17449307747295017006142981453320720946812828330895590310359634430146721583189",
+                )
+                .unwrap(),
+            ),
+        ]);
+
+        // map (key: what to hash, value: expected value)
+        for (k, v) in map.into_iter() {
+            let hasher = Poseidon::<Fr>::from(&ROUND_PARAMS);
+            let h = hasher.hash(&[k]);
+            assert_eq!(h.unwrap(), v);
+        }
+    }
+
+    #[test]
+    fn test_poseidon_hash_multi() {
+        // All hashes done in a merkle tree (with leaves: [0, 1, 2, 3, 4, 5, 6, 7])
+
+        // ~ leaves
+        let fr_0 = Fr::ZERO;
+        let fr_1 = Fr::ONE;
+        let fr_2 = Fr::from(2);
+        let fr_3 = Fr::from(3);
+        let fr_4 = Fr::from(4);
+        let fr_5 = Fr::from(5);
+        let fr_6 = Fr::from(6);
+        let fr_7 = Fr::from(7);
+
+        let fr_0_1 = Fr::from_str(
+            "12583541437132735734108669866114103169564651237895298778035846191048104863326",
+        )
+        .unwrap();
+        let fr_2_3 = Fr::from_str(
+            "17197790661637433027297685226742709599380837544520340689137581733613433332983",
+        )
+        .unwrap();
+        let fr_4_5 = Fr::from_str(
+            "756592041685769348226045093946546956867261766023639881791475046640232555043",
+        )
+        .unwrap();
+        let fr_6_7 = Fr::from_str(
+            "5558359459771725727593826278265342308584225092343962757289948761260561575479",
+        )
+        .unwrap();
+
+        let fr_0_3 = Fr::from_str(
+            "3720616653028013822312861221679392249031832781774563366107458835261883914924",
+        )
+        .unwrap();
+        let fr_4_7 = Fr::from_str(
+            "7960741062684589801276390367952372418815534638314682948141519164356522829957",
+        )
+        .unwrap();
+
+        // ~ root
+        let fr_0_7 = Fr::from_str(
+            "11780650233517635876913804110234352847867393797952240856403268682492028497284",
+        )
+        .unwrap();
+
+        // map (key: what to hash, value: expected value)
+        let map = HashMap::from([
+            ((fr_0, fr_1), fr_0_1),
+            ((fr_2, fr_3), fr_2_3),
+            ((fr_4, fr_5), fr_4_5),
+            ((fr_6, fr_7), fr_6_7),
+            ((fr_0_1, fr_2_3), fr_0_3),
+            ((fr_4_5, fr_6_7), fr_4_7),
+            ((fr_0_3, fr_4_7), fr_0_7),
+        ]);
+
+        for (k, v) in map.into_iter() {
+            let hasher = Poseidon::<Fr>::from(&ROUND_PARAMS);
+            let h = hasher.hash(&[k.0, k.1]);
+            assert_eq!(h.unwrap(), v);
+        }
+    }
+}