Add merkle tree glossary + mermaid graph example (#298 )

Add poseidon hash benchmark + optim (#300 )
fix(tree): fix OptimalMerkleTree set_range & override_range performance issue (#295 )
2026-01-09 13:47:58 -05:00 · 2025-04-18 15:11:55 +02:00 · 2025-04-18 15:08:43 +02:00 · 2025-04-16 17:40:58 +02:00 · 2025-04-16 16:23:58 +02:00 · 2025-04-08 13:37:18 +07:00
108 changed files with 9738 additions and 7987 deletions
--- a/.github/labels.yml
+++ b/.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)
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -3,39 +3,32 @@ on:
    branches:
      - master
    paths-ignore:
-      - '**.md'
-      - '!.github/workflows/*.yml'
-      - '!multiplier/src/**'
-      - '!private-settlement/src/**'
-      - '!rln-wasm/**'
-      - '!rln/src/**'
-      - '!rln/resources/**'
-      - '!semaphore/src/**'
-      - '!utils/src/**'
+      - "**.md"
+      - "!.github/workflows/*.yml"
+      - "!rln-wasm/**"
+      - "!rln/src/**"
+      - "!rln/resources/**"
+      - "!utils/src/**"
  pull_request:
    paths-ignore:
-      - '**.md'
-      - '!.github/workflows/*.yml'
-      - '!multiplier/src/**'
-      - '!private-settlement/src/**'
-      - '!rln-wasm/**'
-      - '!rln/src/**'
-      - '!rln/resources/**'
-      - '!semaphore/src/**'
-      - '!utils/src/**'
-
+      - "**.md"
+      - "!.github/workflows/*.yml"
+      - "!rln-wasm/**"
+      - "!rln/src/**"
+      - "!rln/resources/**"
+      - "!utils/src/**"

 name: Tests

 jobs:
-  test:
+  utils-test:
    strategy:
      matrix:
-        platform: [ubuntu-latest, macos-latest]
-        crate: [multiplier, semaphore, rln, utils]
+        platform: [ ubuntu-latest, macos-latest ]
+        crate: [ utils ]
    runs-on: ${{ matrix.platform }}
    timeout-minutes: 60
-  
+
    name: test - ${{ matrix.crate }} - ${{ matrix.platform }}
    steps:
      - name: Checkout sources
@@ -51,17 +44,49 @@ jobs:
        run: make installdeps
      - name: cargo-make test
        run: |
-            cargo make test --release
+          cargo make test --release
        working-directory: ${{ matrix.crate }}
-  
+
+  rln-test:
+    strategy:
+      matrix:
+        platform: [ ubuntu-latest, macos-latest ]
+        crate: [ rln ]
+        feature: [ "default", "arkzkey", "stateless" ]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: test - ${{ matrix.crate }} - ${{ matrix.platform }} - ${{ matrix.feature }}
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v3
+      - name: Install stable toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+      - uses: Swatinem/rust-cache@v2
+      - name: Install dependencies
+        run: make installdeps
+      - name: 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 }}
+
  rln-wasm:
    strategy:
      matrix:
-        platform: [ubuntu-latest, macos-latest]
+        platform: [ ubuntu-latest, macos-latest ]
+        feature: [ "default", "arkzkey" ]
    runs-on: ${{ matrix.platform }}
    timeout-minutes: 60
-  
-    name: test - rln-wasm - ${{ matrix.platform }}
+
+    name: test - rln-wasm - ${{ matrix.platform }} - ${{ matrix.feature }}
    steps:
      - uses: actions/checkout@v3
      - name: Install stable toolchain
@@ -73,23 +98,33 @@ 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
+      - name: cargo-make build
+        run: |
+          if [ ${{ matrix.feature }} == default ]; then
+            cargo make build
+          else
+            cargo make build_${{ matrix.feature }}
+          fi
        working-directory: rln-wasm
-      - run: cargo make test --release
+      - name: cargo-make test
+        run: |
+          if [ ${{ matrix.feature }} == default ]; then
+            cargo make test --release
+          else
+            cargo make test_${{ matrix.feature }} --release
+          fi
        working-directory: rln-wasm

  lint:
    strategy:
      matrix:
        # we run lint tests only on ubuntu
-        platform: [ubuntu-latest]
-        crate: [multiplier, semaphore, rln, utils]
+        platform: [ ubuntu-latest ]
+        crate: [ rln, rln-wasm, utils ]
    runs-on: ${{ matrix.platform }}
    timeout-minutes: 60

-    name: lint - ${{ matrix.crate }} - ${{ matrix.platform }}  
+    name: lint - ${{ matrix.crate }} - ${{ matrix.platform }}
    steps:
      - name: Checkout sources
        uses: actions/checkout@v3
@@ -110,19 +145,17 @@ 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:
+
+  benchmark-utils:
    # run only in pull requests
    if: github.event_name == 'pull_request'
    strategy:
      matrix:
        # we run benchmark tests only on ubuntu
-        platform: [ubuntu-latest]
-        crate: [rln, utils]
+        platform: [ ubuntu-latest ]
+        crate: [ utils ]
    runs-on: ${{ matrix.platform }}
    timeout-minutes: 60

@@ -134,4 +167,27 @@ jobs:
      - uses: boa-dev/criterion-compare-action@v3
        with:
          branchName: ${{ github.base_ref }}
-          cwd: ${{ matrix.crate }}
+          cwd: ${{ matrix.crate }}
+
+  benchmark-rln:
+    # run only in pull requests
+    if: github.event_name == 'pull_request'
+    strategy:
+      matrix:
+        # we run benchmark tests only on ubuntu
+        platform: [ ubuntu-latest ]
+        crate: [ rln ]
+        feature: [ "default", "arkzkey" ]
+    runs-on: ${{ matrix.platform }}
+    timeout-minutes: 60
+
+    name: benchmark - ${{ matrix.platform }} - ${{ matrix.crate }} - ${{ matrix.feature }}
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v3
+      - uses: Swatinem/rust-cache@v2
+      - uses: boa-dev/criterion-compare-action@v3
+        with:
+          branchName: ${{ github.base_ref }}
+          cwd: ${{ matrix.crate }}
+          features: ${{ matrix.feature }}
--- a/.github/workflows/nightly-release.yml
+++ b/.github/workflows/nightly-release.yml
@@ -8,10 +8,14 @@ jobs:
  linux:
    strategy:
      matrix:
-        target: 
+        feature: [ "default", "arkzkey", "stateless" ]
+        target:
          - x86_64-unknown-linux-gnu
          - aarch64-unknown-linux-gnu
-          - i686-unknown-linux-gnu
+          # - i686-unknown-linux-gnu
+        include:
+          - feature: stateless
+            cargo_args: --exclude rln-cli
    name: Linux build
    runs-on: ubuntu-latest
    steps:
@@ -29,16 +33,16 @@ jobs:
        run: make installdeps
      - name: cross build
        run: |
-          cross build --release --target ${{ matrix.target }} --workspace --exclude rln-wasm
+          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace ${{ matrix.cargo_args }}
          mkdir release
          cp target/${{ matrix.target }}/release/librln* release/
-          tar -czvf ${{ matrix.target }}-rln.tar.gz release/
+          tar -czvf ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz release/

      - name: Upload archive artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
        with:
-          name: ${{ matrix.target }}-archive
-          path: ${{ matrix.target }}-rln.tar.gz
+          name: ${{ matrix.target }}-${{ matrix.feature }}-archive
+          path: ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz
          retention-days: 2

  macos:
@@ -46,9 +50,13 @@ jobs:
    runs-on: macos-latest
    strategy:
      matrix:
-        target: 
+        feature: [ "default", "arkzkey", "stateless" ]
+        target:
          - x86_64-apple-darwin
          - aarch64-apple-darwin
+        include:
+          - feature: stateless
+            cargo_args: --exclude rln-cli
    steps:
      - name: Checkout sources
        uses: actions/checkout@v3
@@ -64,18 +72,18 @@ jobs:
        run: make installdeps
      - name: cross build
        run: |
-          cross build --release --target ${{ matrix.target }} --workspace --exclude rln-wasm
+          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace ${{ matrix.cargo_args }}
          mkdir release
          cp target/${{ matrix.target }}/release/librln* release/
-          tar -czvf ${{ matrix.target }}-rln.tar.gz release/
+          tar -czvf ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz release/

      - name: Upload archive artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
        with:
-          name: ${{ matrix.target }}-archive
-          path: ${{ matrix.target }}-rln.tar.gz
+          name: ${{ matrix.target }}-${{ matrix.feature }}-archive
+          path: ${{ matrix.target }}-${{ matrix.feature }}-rln.tar.gz
          retention-days: 2
-  
+
  browser-rln-wasm:
    name: Browser build (RLN WASM)
    runs-on: ubuntu-latest
@@ -91,8 +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
@@ -102,16 +108,15 @@ jobs:
        working-directory: rln-wasm

      - name: Upload archive artifact
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
        with:
          name: browser-rln-wasm-archive
          path: rln-wasm/browser-rln-wasm.tar.gz
          retention-days: 2

-
  prepare-prerelease:
    name: Prepare pre-release
-    needs: [linux, macos, browser-rln-wasm]
+    needs: [ linux, macos, browser-rln-wasm ]
    runs-on: ubuntu-latest
    steps:
      - name: Checkout code
@@ -119,8 +124,8 @@ jobs:
        with:
          ref: master
      - name: Download artifacts
-        uses: actions/download-artifact@v2
-          
+        uses: actions/download-artifact@v4
+
      - name: Delete tag
        uses: dev-drprasad/delete-tag-and-release@v0.2.1
        with:
@@ -142,7 +147,7 @@ jobs:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Delete artifacts
-        uses: geekyeggo/delete-artifact@v1
+        uses: geekyeggo/delete-artifact@v5
        with:
          failOnError: false
          name: |
--- a/.gitignore
+++ b/.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
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,8 +0,0 @@
-[submodule "rln/vendor/rln"]
-	path = rln/vendor/rln
-	ignore = dirty
-	url = https://github.com/Rate-Limiting-Nullifier/rln_circuits.git
-[submodule "semaphore/vendor/semaphore"]
-	path = semaphore/vendor/semaphore
-	ignore = dirty
-	url = https://github.com/appliedzkp/semaphore.git
--- a/CHANGELOG.md
+++ b/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.
--- a/Cargo.lock
+++ b/Cargo.lock
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,13 +1,6 @@
 [workspace]
-members = [
-  "multiplier",
-  "private-settlement",
-  "semaphore",
-  "rln",
-  "rln-cli",
-  "rln-wasm",
-  "utils",
-]
+members = ["rln", "rln-cli", "rln-wasm", "utils"]
+default-members = ["rln", "rln-cli", "rln-wasm", "utils"]
 resolver = "2"

 # Compilation profile for any non-workspace member.
@@ -15,10 +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"
-
-[profile.release.package."semaphore"]
-codegen-units = 1
--- a/Cross.toml
+++ b/Cross.toml
@@ -29,4 +29,7 @@ image = "ghcr.io/cross-rs/mips64-unknown-linux-gnuabi64:latest"
 image = "ghcr.io/cross-rs/mips64el-unknown-linux-gnuabi64:latest"

 [target.mipsel-unknown-linux-gnu]
-image = "ghcr.io/cross-rs/mipsel-unknown-linux-gnu:latest"
+image = "ghcr.io/cross-rs/mipsel-unknown-linux-gnu:latest"
+
+[target.aarch64-linux-android]
+image = "ghcr.io/cross-rs/aarch64-linux-android:edge"
--- a/21
+++ b/21
@@ -1,4 +1,4 @@
-.PHONY: all installdeps build test clean
+.PHONY: all installdeps build test bench clean

 all: .pre-build build

@@ -13,15 +13,21 @@ endif

 installdeps: .pre-build
 ifeq ($(shell uname),Darwin)
-# commented due to https://github.com/orgs/Homebrew/discussions/4612	
-# @brew update 
+	@brew update
 	@brew install cmake ninja
 else ifeq ($(shell uname),Linux)
 	@sudo apt-get update
 	@sudo apt-get install -y cmake ninja-build
 endif
-	@git clone --recursive https://github.com/WebAssembly/wabt.git
-	@cd wabt && mkdir build && cd build && cmake .. -GNinja && ninja && sudo ninja install
+	@if [ ! -d "$$HOME/.nvm" ]; then \
+		curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.40.2/install.sh | bash; \
+	fi
+	@bash -c 'export NVM_DIR="$$HOME/.nvm" && \
+		[ -s "$$NVM_DIR/nvm.sh" ] && \. "$$NVM_DIR/nvm.sh" && \
+		nvm install 22.14.0 && \
+		nvm use 22.14.0'
+	@curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
+	@echo "\033[1;32m>>> Now run this command to activate Node.js 22.14.0: \033[1;33msource $$HOME/.nvm/nvm.sh && nvm use 22.14.0\033[0m"

 build: .pre-build
 	@cargo make build
@@ -29,5 +35,8 @@ build: .pre-build
 test: .pre-build
 	@cargo make test

+bench: .pre-build
+	@cargo make bench
+
 clean:
-	@cargo clean
+	@cargo clean
--- a/README.md
+++ b/README.md
@@ -1,35 +1,81 @@
 # Zerokit

-A set of Zero Knowledge modules, written in Rust and designed to be used in other system programming environments.
+[![Crates.io](https://img.shields.io/crates/v/rln.svg)](https://crates.io/crates/rln)
+[![GitHub Workflow Status](https://img.shields.io/github/actions/workflow/status/vacp2p/zerokit/ci.yml?branch=master&label=CI)](https://github.com/vacp2p/zerokit/actions)
+[![License: MIT](https://img.shields.io/badge/License-MIT-blue.svg)](https://opensource.org/licenses/MIT)
+[![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)

-## Initial scope
+A collection of Zero Knowledge modules written in Rust and designed to be used in other system programming environments.

-Focus on RLN and being able to use [Circom](https://iden3.io/circom) based
-version through ark-circom, as opposed to the native one that currently exists
-in Rust.
+## Overview

-## Acknowledgements
+Zerokit provides zero-knowledge cryptographic primitives with a focus on performance, security, and usability.
+The current focus is on Rate-Limiting Nullifier [RLN](https://github.com/Rate-Limiting-Nullifier) implementation.

- Uses [ark-circom](https://github.com/gakonst/ark-circom), Rust wrapper around Circom.
+Current implementation is based on the following [specification](https://github.com/vacp2p/rfc-index/blob/main/vac/raw/rln-v2.md)
+and focused on RLNv2 which allows to set a rate limit for the number of messages that can be sent by a user.

- Inspired by Applied ZKP group work, e.g. [zk-kit](https://github.com/appliedzkp/zk-kit).
+## Features

- [RLN library](https://github.com/kilic/rln) written in Rust based on Bellman.
+- **RLN Implementation**: Efficient Rate-Limiting Nullifier using zkSNARKs
+- **Circom Compatibility**: Uses Circom-based circuits for RLN
+- **Cross-Platform**: Support for multiple architectures (see compatibility note below)
+- **FFI-Friendly**: Easy to integrate with other languages

- [semaphore-rs](https://github.com/worldcoin/semaphore-rs) written in Rust based on ark-circom.
+## Architecture
+
+Zerokit currently focuses on RLN (Rate-Limiting Nullifier) implementation using [Circom](https://iden3.io/circom) circuits through ark-circom, providing an alternative to existing native Rust implementations.

 ## Build and Test

-To install missing dependencies, run the following commands from the root folder
+> [!IMPORTANT]
+> For WASM support or x32 architecture builds, use version `0.6.1`. The current version has dependency issues for these platforms. WASM support will return in a future release.
+
+### Install Dependencies
+
 ```bash
 make installdeps
 ```
-To build and test all crates, run the following commands from the root folder
+
+### Build and Test All Crates
+
 ```bash
 make build
 make test
 ```

-## Release assets
+## Release Assets

-We use [`cross-rs`](https://github.com/cross-rs/cross) to cross-compile and generate release assets for rln. 
+We use [`cross-rs`](https://github.com/cross-rs/cross) to cross-compile and generate release assets:
+
+```bash
+# Example: Build for specific target
+cross build --target x86_64-unknown-linux-gnu --release -p rln
+```
+
+## Used By
+
+Zerokit powers zero-knowledge functionality in:
+
+- [**nwaku**](https://github.com/waku-org/nwaku) - Nim implementation of the Waku v2 protocol
+- [**js-rln**](https://github.com/waku-org/js-rln) - JavaScript bindings for RLN
+
+## Acknowledgements
+
+- Inspired by [Applied ZKP](https://zkp.science/) group work, including [zk-kit](https://github.com/appliedzkp/zk-kit)
+- Uses [ark-circom](https://github.com/gakonst/ark-circom) for zkey and Groth16 proof generation
+- Witness calculation based on [circom-witnesscalc](https://github.com/iden3/circom-witnesscalc) by iden3.
+The execution graph file used by this code has been generated by means of the same iden3 software.
+
+> [!IMPORTANT]
+> The circom-witnesscalc code fragments have been borrowed instead of depending on this crate,
+    because its types of input and output data were incompatible with the corresponding zerokit code fragments,
+    and circom-witnesscalc has some dependencies, which are redundant for our purpose.
+
+## Documentation
+
+For detailed documentation on each module:
+
+```bash
+cargo doc --open
+```
--- a/flake.lock
+++ b/flake.lock
@@ -0,0 +1,27 @@
+{
+  "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"
+      }
+    }
+  },
+  "root": "root",
+  "version": 7
+}
--- a/flake.nix
+++ b/flake.nix
@@ -0,0 +1,38 @@
+{
+  description = "A flake for building zerokit";
+
+  inputs = {
+    # Version 24.11
+    nixpkgs.url = "github:NixOS/nixpkgs?rev=f44bd8ca21e026135061a0a57dcf3d0775b67a49";
+  };
+
+  outputs = { self, nixpkgs }: 
+    let
+      stableSystems = [
+        "x86_64-linux" "aarch64-linux"
+        "x86_64-darwin" "aarch64-darwin"
+        "x86_64-windows" "i686-linux"
+        "i686-windows"
+      ];
+      forAllSystems = nixpkgs.lib.genAttrs stableSystems;
+      pkgsFor = forAllSystems (system: import nixpkgs { inherit system; });
+    in rec
+    {
+      packages = forAllSystems (system: let
+        pkgs = pkgsFor.${system};
+      in rec {
+        zerokit-android-arm64 = pkgs.callPackage ./nix/default.nix { target-platform="aarch64-android-prebuilt"; rust-target= "aarch64-linux-android"; };
+        default = zerokit-android-arm64;
+      });
+
+      devShells = forAllSystems (system: let
+        pkgs = pkgsFor.${system};
+      in {
+        default = pkgs.mkShell {
+          inputsFrom = [
+            packages.${system}.default
+          ];
+        };
+      });
+    };
+}
--- a/multiplier/Cargo.toml
+++ b/multiplier/Cargo.toml
@@ -1,32 +0,0 @@
-[package]
-name = "multiplier"
-version = "0.3.0"
-edition = "2018"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-
-# WASM operations
-# wasmer = { version = "2.0" }
-# fnv = { version = "1.0.3", default-features = false }
-# num = { version = "0.4.0" }
-# num-traits = { version = "0.2.0", default-features = false }
-
-# ZKP Generation
-# ark-ff = { version = "0.3.0", default-features = false, features = ["parallel", "asm"] }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-bn254 = { version = "0.3.0" }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-# ark-poly = { version = "^0.3.0", default-features = false, features = ["parallel"] }
-ark-serialize = { version = "0.3.0", default-features = false }
-
-ark-circom = { git = "https://github.com/gakonst/ark-circom", features = ["circom-2"], rev = "35ce5a9" }
-
-# error handling
-color-eyre = "0.6.1"
-
-# decoding of data
-# hex = "0.4.3"
-# byteorder = "1.4.3"
--- a/multiplier/Makefile.toml
+++ b/multiplier/Makefile.toml
@@ -1,7 +0,0 @@
-[tasks.build]
-command = "cargo"
-args = ["build", "--release"]
-
-[tasks.test]
-command = "cargo"
-args = ["test", "--release"]
--- a/multiplier/README.md
+++ b/multiplier/README.md
@@ -1,21 +0,0 @@
-# Multiplier example
-
-Example wrapper around a basic Circom circuit to test Circom 2 integration
-through ark-circom and FFI.
-
-## Build and Test
-
-To build and test, run the following commands within the module folder
-```bash
-cargo make build
-cargo make test
-```
-
-## FFI
-
-To generate C or Nim bindings from Rust FFI, use `cbindgen` or `nbindgen`:
-
-```
-cbindgen . -o target/multiplier.h
-nbindgen . -o target/multiplier.nim
-```
--- a/multiplier/resources/circom2_multiplier2.r1cs
+++ b/multiplier/resources/circom2_multiplier2.r1cs
--- a/multiplier/resources/circom2_multiplier2.wasm
+++ b/multiplier/resources/circom2_multiplier2.wasm
--- a/multiplier/src/ffi.rs
+++ b/multiplier/src/ffi.rs
@@ -1,77 +0,0 @@
-use crate::public::Multiplier;
-use std::slice;
-
-/// Buffer struct is taken from
-/// https://github.com/celo-org/celo-threshold-bls-rs/blob/master/crates/threshold-bls-ffi/src/ffi.rs
-///
-/// Also heavily inspired by https://github.com/kilic/rln/blob/master/src/ffi.rs
-
-#[repr(C)]
-#[derive(Clone, Debug, PartialEq)]
-pub struct Buffer {
-    pub ptr: *const u8,
-    pub len: usize,
-}
-
-impl From<&[u8]> for Buffer {
-    fn from(src: &[u8]) -> Self {
-        Self {
-            ptr: &src[0] as *const u8,
-            len: src.len(),
-        }
-    }
-}
-
-impl<'a> From<&Buffer> for &'a [u8] {
-    fn from(src: &Buffer) -> &'a [u8] {
-        unsafe { slice::from_raw_parts(src.ptr, src.len) }
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn new_circuit(ctx: *mut *mut Multiplier) -> bool {
-    if let Ok(mul) = Multiplier::new() {
-        unsafe { *ctx = Box::into_raw(Box::new(mul)) };
-        true
-    } else {
-        false
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn prove(ctx: *const Multiplier, output_buffer: *mut Buffer) -> bool {
-    println!("multiplier ffi: prove");
-    let mul = unsafe { &*ctx };
-    let mut output_data: Vec<u8> = Vec::new();
-
-    match mul.prove(&mut output_data) {
-        Ok(proof_data) => proof_data,
-        Err(_) => return false,
-    };
-    unsafe { *output_buffer = Buffer::from(&output_data[..]) };
-    std::mem::forget(output_data);
-    true
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn verify(
-    ctx: *const Multiplier,
-    proof_buffer: *const Buffer,
-    result_ptr: *mut u32,
-) -> bool {
-    println!("multiplier ffi: verify");
-    let mul = unsafe { &*ctx };
-    let proof_data = <&[u8]>::from(unsafe { &*proof_buffer });
-    if match mul.verify(proof_data) {
-        Ok(verified) => verified,
-        Err(_) => return false,
-    } {
-        unsafe { *result_ptr = 0 };
-    } else {
-        unsafe { *result_ptr = 1 };
-    };
-    true
-}
--- a/multiplier/src/lib.rs
+++ b/multiplier/src/lib.rs
@@ -1,2 +0,0 @@
-pub mod ffi;
-pub mod public;
--- a/multiplier/src/main.rs
+++ b/multiplier/src/main.rs
@@ -1,49 +0,0 @@
-use ark_circom::{CircomBuilder, CircomConfig};
-use ark_std::rand::thread_rng;
-use color_eyre::{Report, Result};
-
-use ark_bn254::Bn254;
-use ark_groth16::{
-    create_random_proof as prove, generate_random_parameters, prepare_verifying_key, verify_proof,
-};
-
-fn groth16_proof_example() -> Result<()> {
-    let cfg = CircomConfig::<Bn254>::new(
-        "./resources/circom2_multiplier2.wasm",
-        "./resources/circom2_multiplier2.r1cs",
-    )?;
-
-    let mut builder = CircomBuilder::new(cfg);
-    builder.push_input("a", 3);
-    builder.push_input("b", 11);
-
-    // create an empty instance for setting it up
-    let circom = builder.setup();
-
-    let mut rng = thread_rng();
-    let params = generate_random_parameters::<Bn254, _, _>(circom, &mut rng)?;
-
-    let circom = builder.build()?;
-
-    let inputs = circom
-        .get_public_inputs()
-        .ok_or(Report::msg("no public inputs"))?;
-
-    let proof = prove(circom, &params, &mut rng)?;
-
-    let pvk = prepare_verifying_key(&params.vk);
-
-    match verify_proof(&pvk, &proof, &inputs) {
-        Ok(_) => Ok(()),
-        Err(_) => Err(Report::msg("not verified")),
-    }
-}
-
-fn main() {
-    println!("Hello, world!");
-
-    match groth16_proof_example() {
-        Ok(_) => println!("Success"),
-        Err(_) => println!("Error"),
-    }
-}
--- a/multiplier/src/public.rs
+++ b/multiplier/src/public.rs
@@ -1,79 +0,0 @@
-use ark_circom::{CircomBuilder, CircomCircuit, CircomConfig};
-use ark_std::rand::thread_rng;
-
-use ark_bn254::Bn254;
-use ark_groth16::{
-    create_random_proof as prove, generate_random_parameters, prepare_verifying_key, verify_proof,
-    Proof, ProvingKey,
-};
-use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
-use color_eyre::{Report, Result};
-use std::io::{Read, Write};
-
-pub struct Multiplier {
-    circom: CircomCircuit<Bn254>,
-    params: ProvingKey<Bn254>,
-}
-
-impl Multiplier {
-    // TODO Break this apart here
-    pub fn new() -> Result<Multiplier> {
-        let cfg = CircomConfig::<Bn254>::new(
-            "./resources/circom2_multiplier2.wasm",
-            "./resources/circom2_multiplier2.r1cs",
-        )?;
-
-        let mut builder = CircomBuilder::new(cfg);
-        builder.push_input("a", 3);
-        builder.push_input("b", 11);
-
-        // create an empty instance for setting it up
-        let circom = builder.setup();
-
-        let mut rng = thread_rng();
-
-        let params = generate_random_parameters::<Bn254, _, _>(circom, &mut rng)?;
-
-        let circom = builder.build()?;
-
-        Ok(Multiplier { circom, params })
-    }
-
-    // TODO Input Read
-    pub fn prove<W: Write>(&self, result_data: W) -> Result<()> {
-        let mut rng = thread_rng();
-
-        // XXX: There's probably a better way to do this
-        let circom = self.circom.clone();
-        let params = self.params.clone();
-
-        let proof = prove(circom, &params, &mut rng)?;
-
-        // XXX: Unclear if this is different from other serialization(s)
-        proof.serialize(result_data)?;
-
-        Ok(())
-    }
-
-    pub fn verify<R: Read>(&self, input_data: R) -> Result<bool> {
-        let proof = Proof::deserialize(input_data)?;
-
-        let pvk = prepare_verifying_key(&self.params.vk);
-
-        // XXX Part of input data?
-        let inputs = self
-            .circom
-            .get_public_inputs()
-            .ok_or(Report::msg("no public inputs"))?;
-
-        let verified = verify_proof(&pvk, &proof, &inputs)?;
-
-        Ok(verified)
-    }
-}
-
-impl Default for Multiplier {
-    fn default() -> Self {
-        Self::new().unwrap()
-    }
-}
--- a/multiplier/tests/public.rs
+++ b/multiplier/tests/public.rs
@@ -1,21 +0,0 @@
-#[cfg(test)]
-mod tests {
-    use multiplier::public::Multiplier;
-
-    #[test]
-    fn multiplier_proof() {
-        let mul = Multiplier::new().unwrap();
-
-        let mut output_data: Vec<u8> = Vec::new();
-        let _ = mul.prove(&mut output_data);
-
-        let proof_data = &output_data[..];
-
-        // XXX Pass as arg?
-        //let pvk = prepare_verifying_key(&mul.params.vk);
-
-        let verified = mul.verify(proof_data).unwrap();
-
-        assert!(verified);
-    }
-}
--- a/nix/default.nix
+++ b/nix/default.nix
@@ -0,0 +1,35 @@
+{ 
+  pkgs,
+  target-platform ? "aarch64-android-prebuilt",
+  rust-target ? "aarch64-linux-android",
+}:
+
+pkgs.pkgsCross.${target-platform}.rustPlatform.buildRustPackage {
+  pname = "zerokit";
+  version = "nightly";
+
+  src = ../.;
+
+  cargoLock = {
+    lockFile = ../Cargo.lock;
+    allowBuiltinFetchGit = true;
+  };
+
+  CARGO_HOME = "/tmp";
+
+  buildPhase = ''
+    pushd rln
+    cargo rustc --crate-type=cdylib --release --lib --target=${rust-target}
+    popd
+  '';
+
+  installPhase = ''
+    mkdir -p $out/
+    cp ./target/${rust-target}/release/librln.so $out/
+  '';
+
+  meta = with pkgs.lib; {
+    description = "Zerokit";
+    license = licenses.mit;
+  };
+}
--- a/private-settlement/Cargo.toml
+++ b/private-settlement/Cargo.toml
@@ -1,9 +0,0 @@
-[package]
-name = "private-settlement"
-version = "0.3.0"
-edition = "2021"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
--- a/private-settlement/Makefile.toml
+++ b/private-settlement/Makefile.toml
@@ -1,7 +0,0 @@
-[tasks.build]
-command = "cargo"
-args = ["build", "--release"]
-
-[tasks.test]
-command = "cargo"
-args = ["test", "--release"]
--- a/private-settlement/README.md
+++ b/private-settlement/README.md
@@ -1,11 +0,0 @@
-# Private Settlement  Module
-
-This module is to provide APIs to manage, compute and verify [Private Settlement](https://rfc.vac.dev/spec/44/) zkSNARK proofs and primitives.
-
-## Build and Test
-
-To build and test, run the following commands within the module folder
-```bash
-cargo make build
-cargo make test
-```
--- a/private-settlement/src/lib.rs
+++ b/private-settlement/src/lib.rs
@@ -1 +0,0 @@
-
--- a/private-settlement/tests/private-settlement.rs
+++ b/private-settlement/tests/private-settlement.rs
@@ -1,11 +0,0 @@
-#[cfg(test)]
-mod tests {
-    #[cfg(test)]
-    mod tests {
-        #[test]
-        fn it_works() {
-            let result = 2 + 2;
-            assert_eq!(result, 4);
-        }
-    }
-}
--- a/rln-cli/Cargo.toml
+++ b/rln-cli/Cargo.toml
@@ -1,13 +1,27 @@
 [package]
 name = "rln-cli"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"

+[[example]]
+name = "relay"
+path = "src/examples/relay.rs"
+
+[[example]]
+name = "stateless"
+path = "src/examples/stateless.rs"
+required-features = ["stateless"]
+
 [dependencies]
-rln = { path = "../rln" }
-clap = { version = "4.2.7", features = ["cargo", "derive", "env"]}
-clap_derive = { version = "=4.2.0" }
-color-eyre = "=0.6.2"
-# serialization
-serde_json = "1.0.48"
-serde = { version = "1.0.130", features = ["derive"] }
+rln = { path = "../rln", default-features = false }
+zerokit_utils = { path = "../utils" }
+clap = { version = "4.5.35", features = ["cargo", "derive", "env"] }
+clap_derive = { version = "4.5.32" }
+color-eyre = "0.6.3"
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
+
+[features]
+default = []
+arkzkey = ["rln/arkzkey"]
+stateless = ["rln/stateless"]
--- a/rln-cli/Makefile.toml
+++ b/rln-cli/Makefile.toml
@@ -0,0 +1,9 @@
+[tasks.build]
+command = "cargo"
+args = ["build"]
+
+[tasks.test]
+disabled = true
+
+[tasks.bench]
+disabled = true
--- a/rln-cli/README.md
+++ b/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>
+```
--- a/rln-cli/example.config.json
+++ b/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
+}
--- a/rln-cli/src/commands.rs
+++ b/rln-cli/src/commands.rs
@@ -1,47 +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, 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 {
@@ -50,7 +54,7 @@ pub(crate) enum Commands {
    },
    Verify {
        #[arg(short, long)]
-        file: PathBuf,
+        input: PathBuf,
    },
    GenerateProof {
        #[arg(short, long)]
--- a/rln-cli/src/config.rs
+++ b/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()
    }
 }
--- a/rln-cli/src/examples/relay.rs
+++ b/rln-cli/src/examples/relay.rs
@@ -0,0 +1,317 @@
+use std::{
+    collections::HashMap,
+    fs::File,
+    io::{stdin, stdout, Cursor, Read, Write},
+    path::{Path, PathBuf},
+};
+
+use clap::{Parser, Subcommand};
+use color_eyre::{eyre::eyre, Result};
+use rln::{
+    circuit::Fr,
+    hashers::{hash_to_field, poseidon_hash},
+    protocol::{keygen, prepare_prove_input, prepare_verify_input},
+    public::RLN,
+    utils::{bytes_le_to_fr, fr_to_bytes_le, generate_input_buffer},
+};
+
+const MESSAGE_LIMIT: u32 = 1;
+
+const TREEE_HEIGHT: usize = 20;
+
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    #[command(subcommand)]
+    command: Commands,
+}
+
+#[derive(Subcommand)]
+enum Commands {
+    List,
+    Register,
+    Send {
+        #[arg(short, long)]
+        user_index: usize,
+        #[arg(short, long)]
+        message_id: u32,
+        #[arg(short, long)]
+        signal: String,
+    },
+    Clear,
+    Exit,
+}
+
+#[derive(Debug, Clone)]
+struct Identity {
+    identity_secret_hash: Fr,
+    id_commitment: Fr,
+}
+
+impl Identity {
+    fn new() -> Self {
+        let (identity_secret_hash, id_commitment) = keygen();
+        Identity {
+            identity_secret_hash,
+            id_commitment,
+        }
+    }
+}
+
+struct RLNSystem {
+    rln: RLN,
+    used_nullifiers: HashMap<[u8; 32], Vec<u8>>,
+    local_identities: HashMap<usize, Identity>,
+}
+
+impl RLNSystem {
+    fn new() -> Result<Self> {
+        let mut resources: Vec<Vec<u8>> = Vec::new();
+        let resources_path: PathBuf = format!("../rln/resources/tree_height_{TREEE_HEIGHT}").into();
+        #[cfg(feature = "arkzkey")]
+        let filenames = ["rln_final.arkzkey", "graph.bin"];
+        #[cfg(not(feature = "arkzkey"))]
+        let filenames = ["rln_final.zkey", "graph.bin"];
+        for filename in filenames {
+            let fullpath = resources_path.join(Path::new(filename));
+            let mut file = File::open(&fullpath)?;
+            let metadata = std::fs::metadata(&fullpath)?;
+            let mut output_buffer = vec![0; metadata.len() as usize];
+            file.read_exact(&mut output_buffer)?;
+            resources.push(output_buffer);
+        }
+        let rln = RLN::new_with_params(
+            TREEE_HEIGHT,
+            resources[0].clone(),
+            resources[1].clone(),
+            generate_input_buffer(),
+        )?;
+        println!("RLN instance initialized successfully");
+        Ok(RLNSystem {
+            rln,
+            used_nullifiers: HashMap::new(),
+            local_identities: HashMap::new(),
+        })
+    }
+
+    fn list_users(&self) {
+        if self.local_identities.is_empty() {
+            println!("No users registered yet.");
+            return;
+        }
+
+        println!("Registered users:");
+        for (index, identity) in &self.local_identities {
+            println!("User Index: {index}");
+            println!("+ Identity Secret Hash: {}", identity.identity_secret_hash);
+            println!("+ Identity Commitment: {}", identity.id_commitment);
+            println!();
+        }
+    }
+
+    fn register_user(&mut self) -> Result<usize> {
+        let index = self.rln.leaves_set();
+        let identity = Identity::new();
+
+        let rate_commitment = poseidon_hash(&[identity.id_commitment, Fr::from(MESSAGE_LIMIT)]);
+        let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
+        match self.rln.set_next_leaf(&mut buffer) {
+            Ok(_) => {
+                println!("Registered User Index: {index}");
+                println!("+ Identity secret hash: {}", identity.identity_secret_hash);
+                println!("+ Identity commitment: {},", identity.id_commitment);
+                self.local_identities.insert(index, identity);
+            }
+            Err(_) => {
+                println!("Maximum user limit reached: 2^{TREEE_HEIGHT}");
+            }
+        };
+
+        Ok(index)
+    }
+
+    fn generate_proof(
+        &mut self,
+        user_index: usize,
+        message_id: u32,
+        signal: &str,
+        external_nullifier: Fr,
+    ) -> Result<Vec<u8>> {
+        let identity = match self.local_identities.get(&user_index) {
+            Some(identity) => identity,
+            None => return Err(eyre!("user index {user_index} not found")),
+        };
+
+        let serialized = prepare_prove_input(
+            identity.identity_secret_hash,
+            user_index,
+            Fr::from(MESSAGE_LIMIT),
+            Fr::from(message_id),
+            external_nullifier,
+            signal.as_bytes(),
+        );
+        let mut input_buffer = Cursor::new(serialized);
+        let mut output_buffer = Cursor::new(Vec::new());
+        self.rln
+            .generate_rln_proof(&mut input_buffer, &mut output_buffer)?;
+
+        println!("Proof generated successfully:");
+        println!("+ User Index: {user_index}");
+        println!("+ Message ID: {message_id}");
+        println!("+ Signal: {signal}");
+
+        Ok(output_buffer.into_inner())
+    }
+
+    fn verify_proof(&mut self, proof_data: Vec<u8>, signal: &str) -> Result<()> {
+        let proof_with_signal = prepare_verify_input(proof_data.clone(), signal.as_bytes());
+        let mut input_buffer = Cursor::new(proof_with_signal);
+
+        match self.rln.verify_rln_proof(&mut input_buffer) {
+            Ok(true) => {
+                let nullifier = &proof_data[256..288];
+                let nullifier_key: [u8; 32] = nullifier.try_into()?;
+
+                if let Some(previous_proof) = self.used_nullifiers.get(&nullifier_key) {
+                    self.handle_duplicate_message_id(previous_proof.clone(), proof_data)?;
+                    return Ok(());
+                }
+                self.used_nullifiers.insert(nullifier_key, proof_data);
+                println!("Message verified and accepted");
+            }
+            Ok(false) => {
+                println!("Verification failed: message_id must be unique within the epoch and satisfy 0 <= message_id < MESSAGE_LIMIT: {MESSAGE_LIMIT}");
+            }
+            Err(err) => return Err(err),
+        }
+        Ok(())
+    }
+
+    fn handle_duplicate_message_id(
+        &mut self,
+        previous_proof: Vec<u8>,
+        current_proof: Vec<u8>,
+    ) -> Result<()> {
+        let x = &current_proof[192..224];
+        let y = &current_proof[224..256];
+
+        let prev_x = &previous_proof[192..224];
+        let prev_y = &previous_proof[224..256];
+        if x == prev_x && y == prev_y {
+            return Err(eyre!("this exact message and signal has already been sent"));
+        }
+
+        let mut proof1 = Cursor::new(previous_proof);
+        let mut proof2 = Cursor::new(current_proof);
+        let mut output = Cursor::new(Vec::new());
+
+        match self
+            .rln
+            .recover_id_secret(&mut proof1, &mut proof2, &mut output)
+        {
+            Ok(_) => {
+                let output_data = output.into_inner();
+                let (leaked_identity_secret_hash, _) = bytes_le_to_fr(&output_data);
+
+                if let Some((user_index, identity)) = self
+                    .local_identities
+                    .iter()
+                    .find(|(_, identity)| {
+                        identity.identity_secret_hash == leaked_identity_secret_hash
+                    })
+                    .map(|(index, identity)| (*index, identity))
+                {
+                    let real_identity_secret_hash = identity.identity_secret_hash;
+                    if leaked_identity_secret_hash != real_identity_secret_hash {
+                        Err(eyre!("identity secret hash mismatch {leaked_identity_secret_hash} != {real_identity_secret_hash}"))
+                    } else {
+                        println!("DUPLICATE message ID detected! Reveal identity secret hash: {leaked_identity_secret_hash}");
+                        self.local_identities.remove(&user_index);
+                        self.rln.delete_leaf(user_index)?;
+                        println!("User index {user_index} has been SLASHED");
+                        Ok(())
+                    }
+                } else {
+                    Err(eyre!(
+                        "user identity secret hash {leaked_identity_secret_hash} not found"
+                    ))
+                }
+            }
+            Err(err) => Err(eyre!("Failed to recover identity secret: {err}")),
+        }
+    }
+}
+
+fn main() -> Result<()> {
+    println!("Initializing RLN instance...");
+    print!("\x1B[2J\x1B[1;1H");
+    let mut rln_system = RLNSystem::new()?;
+    let rln_epoch = hash_to_field(b"epoch");
+    let rln_identifier = hash_to_field(b"rln-identifier");
+    let external_nullifier = poseidon_hash(&[rln_epoch, rln_identifier]);
+    println!("RLN Relay Example:");
+    println!("Message Limit: {MESSAGE_LIMIT}");
+    println!("----------------------------------");
+    println!();
+    show_commands();
+    loop {
+        print!("\n> ");
+        stdout().flush()?;
+        let mut input = String::new();
+        stdin().read_line(&mut input)?;
+        let trimmed = input.trim();
+        let args = std::iter::once("").chain(trimmed.split_whitespace());
+
+        match Cli::try_parse_from(args) {
+            Ok(cli) => match cli.command {
+                Commands::List => {
+                    rln_system.list_users();
+                }
+                Commands::Register => {
+                    rln_system.register_user()?;
+                }
+                Commands::Send {
+                    user_index,
+                    message_id,
+                    signal,
+                } => {
+                    match rln_system.generate_proof(
+                        user_index,
+                        message_id,
+                        &signal,
+                        external_nullifier,
+                    ) {
+                        Ok(proof) => {
+                            if let Err(err) = rln_system.verify_proof(proof, &signal) {
+                                println!("Verification error: {err}");
+                            };
+                        }
+                        Err(err) => {
+                            println!("Proof generation error: {err}");
+                        }
+                    }
+                }
+                Commands::Clear => {
+                    print!("\x1B[2J\x1B[1;1H");
+                    show_commands();
+                }
+                Commands::Exit => {
+                    break;
+                }
+            },
+            Err(err) => {
+                eprintln!("Command error: {err}");
+            }
+        }
+    }
+    Ok(())
+}
+
+fn show_commands() {
+    println!("Available commands:");
+    println!("  list                                        - List registered users");
+    println!("  register                                    - Register a new user index");
+    println!("  send -u <index> -m <message_id> -s <signal> - Send a message with proof");
+    println!("  clear                                       - Clear the screen");
+    println!("  exit                                        - Exit the program");
+}
--- a/rln-cli/src/examples/stateless.rs
+++ b/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");
+}
--- a/rln-cli/src/main.rs
+++ b/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;
@@ -20,71 +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,
+            resources_path,
        }) => {
            let mut resources: Vec<Vec<u8>> = Vec::new();
-            for filename in ["rln.wasm", "rln_final.zkey", "verification_key.json"] {
-                let fullpath = config.join(Path::new(filename));
+            #[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 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);
            }
-            state.rln = Some(RLN::new_with_params(
-                *tree_height,
-                resources[0].clone(),
-                resources[1].clone(),
-                resources[2].clone(),
-            )?);
+            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"))?
@@ -95,60 +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(()),
    }
 }
--- a/rln-cli/src/state.rs
+++ b/rln-cli/src/state.rs
@@ -1,20 +1,20 @@
+use std::io::Cursor;
+
 use color_eyre::Result;
 use rln::public::RLN;
-use std::fs::File;

-use crate::config::{InnerConfig, Config};
+use crate::config::{Config, InnerConfig};

 #[derive(Default)]
-pub(crate) struct State<'a> {
-    pub rln: Option<RLN<'a>>,
+pub(crate) struct State {
+    pub rln: Option<RLN>,
 }

-impl<'a> State<'a> {
-    pub(crate) fn load_state() -> Result<State<'a>> {
+impl State {
+    pub(crate) fn load_state() -> Result<State> {
        let config = Config::load_config()?;
-        let rln = if let Some(InnerConfig { file, tree_height }) = config.inner {
-            let resources = File::open(&file)?;
-            Some(RLN::new(tree_height, resources)?)
+        let rln = if let Some(InnerConfig { tree_height, .. }) = config.inner {
+            Some(RLN::new(tree_height, Cursor::new(config.as_bytes()))?)
        } else {
            None
        };
--- a/rln-wasm/Cargo.toml
+++ b/rln-wasm/Cargo.toml
@@ -1,33 +1,39 @@
 [package]
 name = "rln-wasm"
-version = "0.0.9"
+version = "0.1.0"
 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"] }
-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", default-features = false }
+num-bigint = { version = "0.4.6", default-features = false, features = [
+    "rand",
+    "serde",
+] }
+wasm-bindgen = "0.2.100"
+serde-wasm-bindgen = "0.6.5"
+js-sys = "0.3.77"
+serde_json = "1.0"

-# The `console_error_panic_hook` crate provides better debugging of panics by
+# 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 = { path = "../utils" }
+
+[target.'cfg(target_arch = "wasm32")'.dependencies]
+getrandom = { version = "0.2.15", features = ["js"] }

 [dev-dependencies]
-wasm-bindgen-test = "0.3.13"
-wasm-bindgen-futures = "0.4.33"
+wasm-bindgen-test = "0.3.50"
+wasm-bindgen-futures = "0.4.50"

+[features]
+default = ["console_error_panic_hook"]
+stateless = ["rln/stateless"]
+arkzkey = ["rln/arkzkey"]
--- a/rln-wasm/Makefile.toml
+++ b/rln-wasm/Makefile.toml
@@ -1,26 +1,53 @@
-[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"]

-[tasks.post-build]
-command = "wasm-strip"
-args = ["./pkg/rln_wasm_bg.wasm"]
+[tasks.build_arkzkey]
+clear = true
+dependencies = ["pack_build_arkzkey", "pack_rename"]
+
+[tasks.pack_build]
+command = "wasm-pack"
+args = ["build", "--release", "--target", "web", "--scope", "waku"]
+env = { "RUSTFLAGS" = "--cfg feature=\"stateless\"" }
+
+[tasks.pack_build_arkzkey]
+command = "wasm-pack"
+args = ["build", "--release", "--target", "web", "--scope", "waku"]
+env = { "RUSTFLAGS" = "--cfg feature=\"stateless\" --cfg feature=\"arkzkey\"" }
+
+[tasks.pack_rename]
+script = "sed -i.bak 's/rln-wasm/zerokit-rln-wasm/g' pkg/package.json && rm pkg/package.json.bak"

 [tasks.test]
 command = "wasm-pack"
-args = ["test", "--release", "--node"]
-dependencies = ["build"]
+args = [
+    "test",
+    "--release",
+    "--node",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--",
+    "--nocapture",
+]
+env = { "RUSTFLAGS" = "--cfg feature=\"stateless\"" }
+
+[tasks.test_arkzkey]
+command = "wasm-pack"
+args = [
+    "test",
+    "--release",
+    "--node",
+    "--target",
+    "wasm32-unknown-unknown",
+    "--",
+    "--nocapture",
+]
+env = { "RUSTFLAGS" = "--cfg feature=\"stateless\" --cfg feature=\"arkzkey\"" }
+dependencies = ["build_arkzkey"]
+
+[tasks.bench]
+disabled = true

 [tasks.login]
 command = "wasm-pack"
--- a/rln-wasm/README.md
+++ b/rln-wasm/README.md
@@ -1,41 +1,55 @@
 # 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`
-```
+> **Note**: This project requires `wasm-pack` for compiling Rust to WebAssembly and `cargo-make` for running the build commands. Make sure both are installed before proceeding.
+
+Install `wasm-pack`:
+
+```bash
 curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
 ```
-2. Install `cargo-make`
-```
+
+Install `cargo-make`
+
+```bash
 cargo install cargo-make
 ```

-OR
+Or install everything needed for `zerokit` at the root of the repository:

-```
+```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
 ```
-cd rln-wasm
-cargo make login
-cargo make publish
-```
--- a/rln-wasm/resources/witness_calculator.js
+++ b/rln-wasm/resources/witness_calculator.js
@@ -1,331 +1,324 @@
 module.exports = async function builder(code, options) {
+  options = 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 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 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 ();
-            }
+  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
-//        );
+  const sanityCheck = options;
+  //        options &&
+  //        (
+  //            options.sanityCheck ||
+  //            options.logGetSignal ||
+  //            options.logSetSignal ||
+  //            options.logStartComponent ||
+  //            options.logFinishComponent
+  //        );

-    
-    wc = new WitnessCalculator(instance, sanityCheck);
-    return wc;
+  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 getMessage() {
+    var message = "";
+    var c = instance.exports.getMessageChar();
+    while (c != 0) {
+      message += String.fromCharCode(c);
+      c = instance.exports.getMessageChar();
    }
-	
-    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);
-	}
+    return message;
+  }

-	// 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());
-	}
+  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;
+  constructor(instance, sanityCheck) {
+    this.instance = instance;

-	this.version = this.instance.exports.getVersion();
-        this.n32 = this.instance.exports.getFieldNumLen32();
+    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.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]);
        }
-        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));
+        try {
+          this.instance.exports.setInputSignal(hMSB, hLSB, i);
+          input_counter++;
+        } catch (err) {
+          // console.log(`After adding signal ${i} of ${k}`)
+          throw new Error(err);
        }
-
-        return w;
+      }
+    });
+    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 calculateBinWitness(input, sanityCheck) {
+  async calculateWitness(input, sanityCheck) {
+    const w = [];

-        const buff32 = new Uint32Array(this.witnessSize*this.n32);
-	const buff = new  Uint8Array( buff32.buffer);
-        await this._doCalculateWitness(input, sanityCheck);
+    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;
+    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;
+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--;
    }
-    if (size) {
-	var i = size - res.length;
-	while (i>0) {
-	    res.unshift(0);
-	    i--;
-	}
-    }
-    return res;
+  }
+  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 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;
+  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 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;
+  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;
 }
--- a/rln-wasm/src/lib.rs
+++ b/rln-wasm/src/lib.rs
@@ -1,16 +1,12 @@
 #![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]
+#[wasm_bindgen(js_name = initPanicHook)]
 pub fn init_panic_hook() {
    console_error_panic_hook::set_once();
 }
@@ -19,7 +15,7 @@ pub fn init_panic_hook() {
 pub struct RLNWrapper {
    // The purpose of this wrapper is to hold a RLN instance with the 'static lifetime
    // because wasm_bindgen does not allow returning elements with lifetimes
-    instance: RLN<'static>,
+    instance: RLN,
 }

 // Macro to call methods with arbitrary amount of arguments,
@@ -61,24 +57,6 @@ 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)*) => {
        {
@@ -150,8 +128,8 @@ impl<T> ProcessArg for Vec<T> {
    }
 }

-impl<'a> ProcessArg for *const RLN<'a> {
-    type ReturnType = &'a RLN<'a>;
+impl ProcessArg for *const RLN {
+    type ReturnType = &'static RLN;
    fn process(self) -> Self::ReturnType {
        unsafe { &*self }
    }
@@ -181,108 +159,31 @@ impl<'a> ProcessArg for &'a [u8] {

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[wasm_bindgen(js_name = newRLN)]
-pub fn wasm_new(
-    tree_height: usize,
-    zkey: Uint8Array,
-    vk: Uint8Array,
-) -> Result<*mut RLNWrapper, String> {
-    let instance = RLN::new_with_params(tree_height, zkey.to_vec(), vk.to_vec())
-        .map_err(|err| format!("{:#?}", err))?;
+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 = getSerializedRLNWitness)]
-pub fn wasm_get_serialized_rln_witness(
-    ctx: *mut RLNWrapper,
-    input: Uint8Array,
-) -> Result<Uint8Array, String> {
-    let rln_witness = call!(ctx, get_serialized_rln_witness, &input.to_vec()[..])
-        .map_err(|err| format!("{:#?}", err))?;
-    Ok(Uint8Array::from(&rln_witness[..]))
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = insertMember)]
-pub fn wasm_set_next_leaf(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(), String> {
-    call_with_error_msg!(
-        ctx,
-        set_next_leaf,
-        "could not insert member into merkle tree".to_string(),
-        &input.to_vec()[..]
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = setLeavesFrom)]
-pub fn wasm_set_leaves_from(
-    ctx: *mut RLNWrapper,
-    index: usize,
-    input: Uint8Array,
-) -> Result<(), String> {
-    call_with_error_msg!(
-        ctx,
-        set_leaves_from,
-        "could not set multiple leaves".to_string(),
-        index,
-        &*input.to_vec()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = deleteLeaf)]
-pub fn wasm_delete_leaf(ctx: *mut RLNWrapper, index: usize) -> Result<(), String> {
-    call_with_error_msg!(ctx, delete_leaf, "could not delete leaf".to_string(), index)
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = setMetadata)]
-pub fn wasm_set_metadata(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(), String> {
-    call_with_error_msg!(
-        ctx,
-        set_metadata,
-        "could not set metadata".to_string(),
-        &*input.to_vec()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = getMetadata)]
-pub fn wasm_get_metadata(ctx: *mut RLNWrapper) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(
-        ctx,
-        get_metadata,
-        "could not get metadata".to_string()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = initTreeWithLeaves)]
-pub fn wasm_init_tree_with_leaves(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(), String> {
-    call_with_error_msg!(
-        ctx,
-        init_tree_with_leaves,
-        "could not init merkle tree".to_string(),
-        &*input.to_vec()
-    )
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = RLNWitnessToJson)]
-pub fn rln_witness_to_json(
+#[wasm_bindgen(js_name = rlnWitnessToJson)]
+pub fn wasm_rln_witness_to_json(
    ctx: *mut RLNWrapper,
    serialized_witness: Uint8Array,
 ) -> Result<Object, String> {
-    let inputs = call!(ctx, get_rln_witness_json, &serialized_witness.to_vec()[..])
-        .map_err(|err| err.to_string())?;
+    let inputs = call!(
+        ctx,
+        get_rln_witness_bigint_json,
+        &serialized_witness.to_vec()[..]
+    )
+    .map_err(|err| err.to_string())?;
    let js_value = serde_wasm_bindgen::to_value(&inputs).map_err(|err| err.to_string())?;
    Object::from_entries(&js_value).map_err(|err| format!("{:#?}", err))
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen]
-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,
@@ -362,17 +263,6 @@ pub fn wasm_recover_id_secret(
    )
 }

-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = verifyRLNProof)]
-pub fn wasm_verify_rln_proof(ctx: *const RLNWrapper, proof: Uint8Array) -> Result<bool, String> {
-    call_bool_method_with_error_msg!(
-        ctx,
-        verify_rln_proof,
-        "error while verifying rln proof".to_string(),
-        &proof.to_vec()[..]
-    )
-}
-
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[wasm_bindgen(js_name = verifyWithRoots)]
 pub fn wasm_verify_with_roots(
@@ -389,12 +279,6 @@ pub fn wasm_verify_with_roots(
    )
 }

-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[wasm_bindgen(js_name = getRoot)]
-pub fn wasm_get_root(ctx: *const RLNWrapper) -> Result<Uint8Array, String> {
-    call_with_output_and_error_msg!(ctx, get_root, "could not obtain root")
-}
-
 #[wasm_bindgen(js_name = hash)]
 pub fn wasm_hash(input: Uint8Array) -> Result<Uint8Array, String> {
    fn_call_with_output_and_error_msg!(hash, "could not generate hash", &input.to_vec()[..])
--- a/rln-wasm/src/utils.js
+++ b/rln-wasm/src/utils.js
@@ -3,16 +3,24 @@ 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);
-    },
+  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);
-    }
-}
+  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
+    );
+  },
+};
--- a/rln-wasm/tests/rln-wasm.rs
+++ b/rln-wasm/tests/rln-wasm.rs
@@ -2,12 +2,16 @@

 #[cfg(test)]
 mod tests {
-    use js_sys::{BigInt as JsBigInt, Object, Uint8Array};
-    use rln::circuit::TEST_TREE_HEIGHT;
-    use rln::utils::normalize_usize;
+    use js_sys::{BigInt as JsBigInt, Date, Object, Uint8Array};
+    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
+    use rln::hashers::{hash_to_field, poseidon_hash};
+    use rln::poseidon_tree::PoseidonTree;
+    use rln::protocol::{prepare_verify_input, rln_witness_from_values, serialize_witness};
+    use rln::utils::{bytes_le_to_fr, fr_to_bytes_le};
    use rln_wasm::*;
    use wasm_bindgen::{prelude::*, JsValue};
    use wasm_bindgen_test::wasm_bindgen_test;
+    use zerokit_utils::merkle_tree::merkle_tree::ZerokitMerkleTree;

    #[wasm_bindgen(module = "src/utils.js")]
    extern "C" {
@@ -18,118 +22,268 @@ mod tests {
        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 test_basic_flow() {
-        let tree_height = TEST_TREE_HEIGHT;
-        let circom_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln.wasm");
-        let zkey_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln_final.zkey");
-        let vk_path =
-            format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/verification_key.json");
-        let zkey = read_file(&zkey_path).unwrap();
-        let vk = read_file(&vk_path).unwrap();
+    pub async fn rln_wasm_benchmark() {
+        let mut results = String::from("\nbenchmarks:\n");
+        let iterations = 10;

-        // Creating an instance of RLN
-        let rln_instance = wasm_new(tree_height, zkey, vk).unwrap();
+        let zkey = read_file(&ZKEY_PATH).expect("Failed to read zkey file");

-        // Creating membership key
-        let mem_keys = wasm_key_gen(rln_instance).unwrap();
-        let idkey = mem_keys.subarray(0, 32);
-        let idcommitment = mem_keys.subarray(32, 64);
+        // 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;

-        // Insert PK
-        wasm_set_next_leaf(rln_instance, idcommitment).unwrap();
+        // 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");

-        // Prepare the message
-        let signal = "Hello World".as_bytes();
+        // 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;

-        // Setting up the epoch (With 0s for the test)
-        let epoch = Uint8Array::new_with_length(32);
-        epoch.fill(0, 0, 32);
+        // 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 identity_index: usize = 0;
+        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]);

-        // Serializing the message
-        let mut serialized_vec: Vec<u8> = Vec::new();
-        serialized_vec.append(&mut idkey.to_vec());
-        serialized_vec.append(&mut normalize_usize(identity_index));
-        serialized_vec.append(&mut epoch.to_vec());
-        serialized_vec.append(&mut normalize_usize(signal.len()));
-        serialized_vec.append(&mut signal.to_vec());
-        let serialized_message = Uint8Array::from(&serialized_vec[..]);
+        let identity_index = tree.leaves_set();

-        let serialized_rln_witness =
-            wasm_get_serialized_rln_witness(rln_instance, serialized_message).unwrap();
+        let user_message_limit = Fr::from(100);
+
+        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+        tree.update_next(rate_commitment)
+            .expect("Failed to update tree");
+
+        let message_id = Fr::from(0);
+        let signal: [u8; 32] = [0; 32];
+        let x = hash_to_field(&signal);
+
+        let merkle_proof = tree
+            .proof(identity_index)
+            .expect("Failed to generate merkle proof");
+
+        let rln_witness = rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x,
+            external_nullifier,
+            user_message_limit,
+            message_id,
+        )
+        .expect("Failed to create RLN witness");
+
+        let serialized_witness =
+            serialize_witness(&rln_witness).expect("Failed to serialize witness");
+        let witness_buffer = Uint8Array::from(&serialized_witness[..]);
+
+        let json_inputs = wasm_rln_witness_to_json(rln_instance, witness_buffer.clone())
+            .expect("Failed to convert witness to JSON");
+
+        // Benchmark calculateWitness
+        let start_calculate_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = calculateWitness(&CIRCOM_PATH, json_inputs.clone())
+                .await
+                .expect("Failed to calculate witness");
+        }
+        let calculate_witness_result = Date::now() - start_calculate_witness;
+
+        // Calculate witness for other benchmarks
+        let calculated_witness_json = calculateWitness(&CIRCOM_PATH, json_inputs)
+            .await
+            .expect("Failed to calculate witness")
+            .as_string()
+            .expect("Failed to convert calculated witness to string");
+        let calculated_witness_vec_str: Vec<String> =
+            serde_json::from_str(&calculated_witness_json).expect("Failed to parse JSON");
+        let calculated_witness: Vec<JsBigInt> = calculated_witness_vec_str
+            .iter()
+            .map(|x| JsBigInt::new(&x.into()).expect("Failed to create JsBigInt"))
+            .collect();
+
+        // Benchmark wasm_generate_rln_proof_with_witness
+        let start_wasm_generate_rln_proof_with_witness = Date::now();
+        for _ in 0..iterations {
+            let _ = wasm_generate_rln_proof_with_witness(
+                rln_instance,
+                calculated_witness.clone(),
+                witness_buffer.clone(),
+            )
+            .expect("Failed to generate proof");
+        }
+        let wasm_generate_rln_proof_with_witness_result =
+            Date::now() - start_wasm_generate_rln_proof_with_witness;
+
+        // Generate a proof for other benchmarks
+        let proof =
+            wasm_generate_rln_proof_with_witness(rln_instance, calculated_witness, witness_buffer)
+                .expect("Failed to generate proof");
+
+        let proof_data = proof.to_vec();
+        let verify_input = prepare_verify_input(proof_data, &signal);
+        let input_buffer = Uint8Array::from(&verify_input[..]);
+
+        let root = tree.root();
+        let roots_serialized = fr_to_bytes_le(&root);
+        let roots_buffer = Uint8Array::from(&roots_serialized[..]);
+
+        // Benchmark wasm_verify_with_roots
+        let start_wasm_verify_with_roots = Date::now();
+        for _ in 0..iterations {
+            let _ =
+                wasm_verify_with_roots(rln_instance, input_buffer.clone(), roots_buffer.clone())
+                    .expect("Failed to verify proof");
+        }
+        let wasm_verify_with_roots_result = Date::now() - start_wasm_verify_with_roots;
+
+        // Verify the proof with the root
+        let is_proof_valid = wasm_verify_with_roots(rln_instance, input_buffer, roots_buffer)
+            .expect("Failed to verify proof");
+        assert!(is_proof_valid, "verification failed");
+
+        // Format and display results
+        let format_duration = |duration_ms: f64| -> String {
+            let avg_ms = duration_ms / (iterations as f64);
+            if avg_ms >= 1000.0 {
+                format!("{:.3} s", avg_ms / 1000.0)
+            } else {
+                format!("{:.3} ms", avg_ms)
+            }
+        };
+
+        results.push_str(&format!("wasm_new: {}\n", format_duration(wasm_new_result)));
+        results.push_str(&format!(
+            "wasm_key_gen: {}\n",
+            format_duration(wasm_key_gen_result)
+        ));
+        results.push_str(&format!(
+            "calculateWitness: {}\n",
+            format_duration(calculate_witness_result)
+        ));
+        results.push_str(&format!(
+            "wasm_generate_rln_proof_with_witness: {}\n",
+            format_duration(wasm_generate_rln_proof_with_witness_result)
+        ));
+        results.push_str(&format!(
+            "wasm_verify_with_roots: {}\n",
+            format_duration(wasm_verify_with_roots_result)
+        ));
+
+        // Log the results
+        wasm_bindgen_test::console_log!("{results}");
+    }
+
+    #[wasm_bindgen_test]
+    pub async fn rln_wasm_test() {
+        // Read the zkey file
+        let zkey = read_file(&ZKEY_PATH).expect("Failed to read zkey file");
+
+        // Create RLN instance and separated tree
+        let rln_instance = wasm_new(zkey).expect("Failed to create RLN instance");
+        let mut tree = PoseidonTree::default(TEST_TREE_HEIGHT).expect("Failed to create tree");
+
+        // Setting up the epoch and rln_identifier
+        let epoch = hash_to_field(b"test-epoch");
+        let rln_identifier = hash_to_field(b"test-rln-identifier");
+        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+
+        // Generate identity pair
+        let mem_keys = wasm_key_gen(rln_instance).expect("Failed to generate keys");
+        let (identity_secret_hash, _) = bytes_le_to_fr(&mem_keys.subarray(0, 32).to_vec());
+        let (id_commitment, _) = bytes_le_to_fr(&mem_keys.subarray(32, 64).to_vec());
+
+        // Get index of the identity
+        let identity_index = tree.leaves_set();
+
+        // Setting up the user message limit
+        let user_message_limit = Fr::from(100);
+
+        // Updating the tree with the rate commitment
+        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+        tree.update_next(rate_commitment)
+            .expect("Failed to update tree");
+
+        // Generate merkle proof
+        let merkle_proof = tree
+            .proof(identity_index)
+            .expect("Failed to generate merkle proof");
+
+        // Create message id and signal
+        let message_id = Fr::from(0);
+        let signal: [u8; 32] = [0; 32];
+        let x = hash_to_field(&signal);
+
+        // Prepare input for witness calculation
+        let rln_witness = rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x,
+            external_nullifier,
+            user_message_limit,
+            message_id,
+        )
+        .expect("Failed to create RLN witness");
+
+        // Serialize the rln witness
+        let serialized_witness =
+            serialize_witness(&rln_witness).expect("Failed to serialize witness");
+        // Convert the serialized witness to a Uint8Array
+        let witness_buffer = Uint8Array::from(&serialized_witness[..]);

        // Obtaining inputs that should be sent to circom witness calculator
-        let json_inputs =
-            rln_witness_to_json(rln_instance, serialized_rln_witness.clone()).unwrap();
+        let json_inputs = wasm_rln_witness_to_json(rln_instance, witness_buffer.clone())
+            .expect("Failed to convert witness to JSON");

        // Calculating witness with JS
        // (Using a JSON since wasm_bindgen does not like Result<Vec<JsBigInt>,JsValue>)
-        let calculated_witness_json = calculateWitness(&circom_path, json_inputs)
+        let calculated_witness_json = calculateWitness(&CIRCOM_PATH, json_inputs)
            .await
-            .unwrap()
+            .expect("Failed to calculate witness")
            .as_string()
-            .unwrap();
+            .expect("Failed to convert calculated witness to string");
        let calculated_witness_vec_str: Vec<String> =
-            serde_json::from_str(&calculated_witness_json).unwrap();
+            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()).unwrap())
+            .map(|x| JsBigInt::new(&x.into()).expect("Failed to create JsBigInt"))
            .collect();

-        // Generating proof
-        let proof = generate_rln_proof_with_witness(
-            rln_instance,
-            calculated_witness.into(),
-            serialized_rln_witness,
-        )
-        .unwrap();
+        // Generate a proof from the calculated witness
+        let proof =
+            wasm_generate_rln_proof_with_witness(rln_instance, calculated_witness, witness_buffer)
+                .expect("Failed to generate proof");

-        // 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[..]);
+        // Prepare the root for verification
+        let root = tree.root();
+        let roots_serialized = fr_to_bytes_le(&root);
+        let roots_buffer = Uint8Array::from(&roots_serialized[..]);

-        // Validate Proof
-        let is_proof_valid = wasm_verify_rln_proof(rln_instance, proof_with_signal);
+        // Prepare input for proof verification
+        let proof_data = proof.to_vec();
+        let verify_input = prepare_verify_input(proof_data, &signal);
+        let input_buffer = Uint8Array::from(&verify_input[..]);

-        assert!(
-            is_proof_valid.unwrap(),
-            "validating proof generated with wasm failed"
-        );
-
-        // Validating Proof with Roots
-        let root = wasm_get_root(rln_instance).unwrap();
-        let roots = Uint8Array::from(&root.to_vec()[..]);
-        let proof_with_signal = Uint8Array::from(&proof_bytes[..]);
-
-        let is_proof_valid = wasm_verify_with_roots(rln_instance, proof_with_signal, roots);
-        assert!(is_proof_valid.unwrap(), "verifying proof with roots failed");
-    }
-
-    #[wasm_bindgen_test]
-    fn test_metadata() {
-        let tree_height = TEST_TREE_HEIGHT;
-        let circom_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln.wasm");
-        let zkey_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln_final.zkey");
-        let vk_path =
-            format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/verification_key.json");
-        let zkey = read_file(&zkey_path).unwrap();
-        let vk = read_file(&vk_path).unwrap();
-
-        // Creating an instance of RLN
-        let rln_instance = wasm_new(tree_height, zkey, vk).unwrap();
-
-
-        let test_metadata = Uint8Array::new(&JsValue::from_str("test"));
-        // Inserting random metadata
-        wasm_set_metadata(rln_instance, test_metadata.clone()).unwrap();
-
-        // Getting metadata
-        let metadata = wasm_get_metadata(rln_instance).unwrap();
-
-        assert_eq!(metadata.to_vec(), test_metadata.to_vec());
+        // 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");
    }
 }
--- a/rln/Cargo.toml
+++ b/rln/Cargo.toml
@@ -1,9 +1,12 @@
 [package]
 name = "rln"
-version = "0.3.0"
+version = "0.7.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
+documentation = "https://github.com/vacp2p/zerokit"
+homepage = "https://vac.dev"
+repository = "https://github.com/vacp2p/zerokit"

 [lib]
 crate-type = ["rlib", "staticlib"]
@@ -12,54 +15,86 @@ 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 = ["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-bn254 = { version = "0.5.0", features = ["std"] }
+ark-relations = { version = "0.5.1", features = ["std"] }
+ark-ff = { version = "0.5.0", default-features = false, features = [
+    "parallel",
+] }
+ark-ec = { version = "0.5.0", default-features = false, features = [
+    "parallel",
+] }

-# 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"
+color-eyre = "0.6.3"
+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"
-rand = "=0.8.5"
-rand_chacha = "=0.3.1"
-tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
-utils = { package = "zerokit_utils", version = "=0.3.0", path = "../utils/", default-features = false }
+byteorder = "1.5.0"
+cfg-if = "1.0"
+num-bigint = { version = "0.4.6", default-features = false, features = [
+    "rand",
+    "std",
+] }
+num-traits = "0.2.19"
+once_cell = "1.21.3"
+lazy_static = "1.5.0"
+rand = "0.8.5"
+rand_chacha = "0.3.1"
+ruint = { version = "1.14.0", features = ["rand", "serde", "ark-ff-04"] }
+tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+utils = { package = "zerokit_utils", version = "0.5.2", path = "../utils", default-features = false }

 # serialization
-serde_json = "=1.0.96"
-serde = { version = "=1.0.163", features = ["derive"] }
+prost = "0.13.5"
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }

-include_dir = "=0.7.3"
+document-features = { version = "0.2.11", optional = true }

 [dev-dependencies]
-sled = "=0.34.7"
-criterion = { version = "=0.4.0", features = ["html_reports"] }
+sled = "0.34.7"
+criterion = { version = "0.4.0", features = ["html_reports"] }

 [features]
-default = ["parallel", "wasmer/sys-default", "pmtree-ft"]
-parallel = ["ark-ec/parallel", "ark-ff/parallel", "ark-std/parallel", "ark-groth16/parallel", "utils/parallel"]
-wasm = ["wasmer/js", "wasmer/std"]
+default = ["pmtree-ft"]
 fullmerkletree = ["default"]
+stateless = []
+arkzkey = []

 # Note: pmtree feature is still experimental
 pmtree-ft = ["utils/pmtree-ft"]

+[[bench]]
+name = "circuit_loading_arkzkey_benchmark"
+harness = false
+required-features = ["arkzkey"]
+
+[[bench]]
+name = "circuit_loading_benchmark"
+harness = false
+
 [[bench]]
 name = "pmtree_benchmark"
 harness = false
+
+[[bench]]
+name = "poseidon_tree_benchmark"
+harness = false
+
+[package.metadata.docs.rs]
+all-features = true
--- a/rln/Makefile.toml
+++ b/rln/Makefile.toml
@@ -4,7 +4,15 @@ args = ["build", "--release"]

 [tasks.test]
 command = "cargo"
-args = ["test", "--release"]
+args = ["test", "--release", "--", "--nocapture"]
+
+[tasks.test_stateless]
+command = "cargo"
+args = ["test", "--release", "--features", "stateless"]
+
+[tasks.test_arkzkey]
+command = "cargo"
+args = ["test", "--release", "--features", "arkzkey"]

 [tasks.bench]
 command = "cargo"
--- a/rln/README.md
+++ b/rln/README.md
@@ -1,64 +1,17 @@
 # Zerokit RLN Module

-This module provides APIs to manage, compute and verify [RLN](https://rfc.vac.dev/spec/32/) zkSNARK proofs and RLN primitives.
+[![Crates.io](https://img.shields.io/crates/v/rln.svg)](https://crates.io/crates/rln)

-## Pre-requisites
-### Install dependencies and clone repo
+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:

-```sh
-make installdeps
-git clone https://github.com/vacp2p/zerokit.git
-cd zerokit/rln
-```
+- Generate and verify RLN proofs
+- Work with Merkle trees for commitment storage
+- Implement rate-limiting mechanisms for distributed systems

-### Build and Test
+## Quick Start

-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/privacy-scaling-explorations/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 three [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) RLN circuits having Merkle tree of height `15`, `19` and `20`, respectively.
-
-## Getting started
+> [!IMPORTANT]
+> Version 0.6.1 is required for WASM support or x32 architecture. Current version doesn't support these platforms due to dependency issues. WASM support will return in a future release.

 ### Add RLN as dependency

@@ -69,128 +22,263 @@ We start by adding zerokit RLN to our `Cargo.toml`
 rln = { git = "https://github.com/vacp2p/zerokit" }
 ```

-### Create a RLN object
+## Basic Usage Example

-First, we need to create a RLN object for a chosen input Merkle tree size.
-
-Note that we need to pass to RLN object constructor the path where the circuit (`rln.wasm`, built for the input tree size), the corresponding proving key (`rln_final.zkey`) and verification key (`verification_key.json`, optional) are found.
+Note that we need to pass to RLN object constructor the path where the graph file (`graph.bin`, built for the input tree size), the corresponding proving key (`rln_final.zkey`) or (`rln_final_uncompr.arkzkey`) and verification key (`verification_key.arkvkey`, optional) are found.

 In the following we will use [cursors](https://doc.rust-lang.org/std/io/struct.Cursor.html) as readers/writers for interfacing with RLN public APIs.

 ```rust
-use rln::protocol::*;
-use rln::public::*;
 use std::io::Cursor;

-// We set the RLN parameters: 
-// - the tree height;
-// - the circuit resource folder (requires a trailing "/").
-let tree_height = 20;
-let resources = Cursor::new("../zerokit/rln/resources/tree_height_20/");
+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, resources);
+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
+### Comments for the code above for point 4

-We generate an identity keypair
+The `external nullifier` includes two parameters.

-```rust
-// We generate an identity pair
-let mut buffer = Cursor::new(Vec::<u8>::new());
-rln.key_gen(&mut buffer).unwrap();
+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.

-// We deserialize the keygen output to obtain
-// the identiy_secret and id_commitment
-let (identity_secret_hash, id_commitment) = deserialize_identity_pair(buffer.into_inner());
+The second one is `rln_identifier` and it's used to prevent a RLN ZK proof generated for one application to be re-used in another one.
+
+### Features
+
+- **Multiple Backend Support**: Choose between different zkey formats with feature flags
+  - `arkzkey`: Use the optimized Arkworks-compatible zkey format (faster loading)
+  - `stateless`: For stateless proof verification
+- **Pre-compiled Circuits**: Ready-to-use circuits with Merkle tree height of 20
+
+## Building and Testing
+
+### Prerequisites
+
+```sh
+git clone https://github.com/vacp2p/zerokit.git
+make installdeps
+cd zerokit/rln
 ```

-### Add ID commitment to the RLN Merkle tree
+### Build Commands

-```rust
-// We define the tree index where id_commitment will be added
-let id_index = 10;
+```sh
+# Build with default features
+cargo make build

-// We serialize id_commitment and pass it to set_leaf
-let mut buffer = Cursor::new(serialize_field_element(id_commitment));
-rln.set_leaf(id_index, &mut buffer).unwrap();
+# 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
 ```

-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).
+## Advanced: Custom Circuit Compilation

-### Set epoch
+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.

-The epoch, sometimes referred to as _external nullifier_, is 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.
+### 1. Compile ZK Circuits for getting the zkey and verification key files

-```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");
-```
-### Set 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).

-The signal is the message for which we are computing a RLN proof.
+To customize the circuit parameters, modify `circom-rln/circuits/rln.circom`:

-```rust
-// We set our signal 
-let signal = b"RLN is awesome";
+```circom
+pragma circom 2.1.0;
+include "./rln.circom";
+component main { public [x, externalNullifier] } = RLN(N, M);
 ```

-### Generate a RLN proof
+Where:

-We prepare the input to the proof generation routine. 
+- `N`: Merkle tree height, determining the maximum membership capacity (2^N members).

-Input buffer is serialized as `[ identity_key | id_index | epoch | signal_len | signal ]`.
+- `M`: Bit size for range checks, setting an upper bound for the number of messages per epoch (2^M messages).

-```rust
-// We prepare input to the proof generation routine
-let proof_input = prepare_prove_input(identity_secret_hash, id_index, epoch, signal);
+> [!NOTE]
+> However, if `N` is too big, this might require a larger Powers of Tau ceremony than the one hardcoded in `./scripts/build-circuits.sh`, which is `2^14`. \
+> In such case, we refer to the official [Circom documentation](https://docs.circom.io/getting-started/proving-circuits/#powers-of-tau) for instructions on how to run an appropriate Powers of Tau ceremony and Phase 2 in order to compile the desired circuit. \
+> Additionally, while `M` sets an upper bound on the number of messages per epoch (`2^M`), you can configure lower message limit for your use case, as long as it satisfies `user_message_limit ≤ 2^M`. \
+> Currently, the `rln` module comes with a [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) RLN circuit with a Merkle tree of height `20` and a bit size of `16`, allowing up to `2^20` registered members and a `2^16` message limit per epoch.
+
+#### Install circom compiler
+
+You can follow the instructions below or refer to the [installing Circom](https://docs.circom.io/getting-started/installation/#installing-circom) guide for more details, but make sure to use the specific version `v2.1.0`.
+
+```sh
+# Clone the circom repository
+git clone https://github.com/iden3/circom.git
+
+# Checkout the specific version
+cd circom && git checkout v2.1.0
+
+# Build the circom compiler
+cargo build --release
+
+# Install the circom binary globally
+cargo install --path circom
+
+# Check the circom version to ensure it's v2.1.0
+circom --version
 ```

-We are now ready to generate a RLN ZK proof along with the _public outputs_ of the ZK circuit evaluation.
+#### Generate the zkey and verification key files example

-```rust
+```sh
+# Clone the circom-rln repository
+git clone https://github.com/rate-limiting-nullifier/circom-rln

-// 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();
+# Install dependencies
+cd circom-rln && npm install

-// We get the public outputs returned by the circuit evaluation
-let proof_data = out_buffer.into_inner();
+# Build circuits
+./scripts/build-circuits.sh rln
+
+# Use the generated zkey file in subsequent steps
+cp zkeyFiles/rln/final.zkey <path_to_rln_final.zkey>
 ```

-The byte vector `proof_data` is serialized as `[ zk-proof | tree_root | epoch | share_x | share_y | nullifier | rln_identifier ]`.
+### 2. Generate Witness Calculation Graph

+The execution graph file used for witness calculation can be compiled following instructions in the [circom-witnesscalc](https://github.com/iden3/circom-witnesscalc) repository.
+As mentioned in step 1, we should use `rln.circom` file from `circom-rln` repository.

-### Verify a RLN proof
+```sh
+# Clone the circom-witnesscalc repository
+git clone https://github.com/iden3/circom-witnesscalc

-We prepare the input to the proof verification routine. 
+# Load the submodules
+cd circom-witnesscalc && git submodule update --init --recursive

-Input buffer is serialized as `[proof_data | signal_len | signal ]`, where `proof_data` is (computed as) the output obtained by `generate_rln_proof`.
+# Build the circom-witnesscalc tool
+cargo build

-```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();
+# Generate the witness calculation graph
+cargo run --package circom_witnesscalc --bin build-circuit ../circom-rln/circuits/rln.circom <path_to_graph.bin>
 ```

-We check if the proof verification was successful: 
-```rust
-// We ensure the proof is valid
-assert!(verified);
+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>
 ```

-## Get involved!
+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.

 We invite you to check our API documentation by running
+
 ```rust
 cargo doc --no-deps
 ```
-and look at unit tests to have an hint on how to interface and use them.
+
+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
--- a/rln/benches/circuit_loading_arkzkey_benchmark.rs
+++ b/rln/benches/circuit_loading_arkzkey_benchmark.rs
@@ -0,0 +1,25 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use rln::circuit::{read_arkzkey_from_bytes_uncompressed, ARKZKEY_BYTES};
+
+pub fn uncompressed_bench(c: &mut Criterion) {
+    let arkzkey = ARKZKEY_BYTES.to_vec();
+    let size = arkzkey.len() as f32;
+    println!(
+        "Size of uncompressed arkzkey: {:.2?} MB",
+        size / 1024.0 / 1024.0
+    );
+
+    c.bench_function("arkzkey::arkzkey_from_raw_uncompressed", |b| {
+        b.iter(|| {
+            let r = read_arkzkey_from_bytes_uncompressed(&arkzkey);
+            assert_eq!(r.is_ok(), true);
+        })
+    });
+}
+
+criterion_group! {
+    name = benches;
+    config = Criterion::default().sample_size(10);
+    targets = uncompressed_bench
+}
+criterion_main!(benches);
--- a/rln/benches/circuit_loading_benchmark.rs
+++ b/rln/benches/circuit_loading_benchmark.rs
@@ -0,0 +1,24 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use rln::circuit::zkey::read_zkey;
+use std::io::Cursor;
+
+pub fn zkey_load_benchmark(c: &mut Criterion) {
+    let zkey = rln::circuit::ZKEY_BYTES.to_vec();
+    let size = zkey.len() as f32;
+    println!("Size of zkey: {:.2?} MB", size / 1024.0 / 1024.0);
+
+    c.bench_function("zkey::zkey_from_raw", |b| {
+        b.iter(|| {
+            let mut reader = Cursor::new(zkey.clone());
+            let r = read_zkey(&mut reader);
+            assert_eq!(r.is_ok(), true);
+        })
+    });
+}
+
+criterion_group! {
+    name = benches;
+    config = Criterion::default().sample_size(10);
+    targets = zkey_load_benchmark
+}
+criterion_main!(benches);
--- a/rln/benches/pmtree_benchmark.rs
+++ b/rln/benches/pmtree_benchmark.rs
@@ -1,7 +1,6 @@
 use criterion::{criterion_group, criterion_main, Criterion};
-use utils::ZerokitMerkleTree;
-
 use rln::{circuit::Fr, pm_tree_adapter::PmTree};
+use utils::ZerokitMerkleTree;

 pub fn pmtree_benchmark(c: &mut Criterion) {
    let mut tree = PmTree::default(2).unwrap();
@@ -22,7 +21,7 @@ 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();
        })
    });
@@ -38,6 +37,19 @@ pub fn pmtree_benchmark(c: &mut Criterion) {
            tree.get(0).unwrap();
        })
    });
+
+    // check intermediate node getter which required additional computation of sub root index
+    c.bench_function("Pmtree::get_subtree_root", |b| {
+        b.iter(|| {
+            tree.get_subtree_root(1, 0).unwrap();
+        })
+    });
+
+    c.bench_function("Pmtree::get_empty_leaves_indices", |b| {
+        b.iter(|| {
+            tree.get_empty_leaves_indices();
+        })
+    });
 }

 criterion_group!(benches, pmtree_benchmark);
--- a/rln/benches/poseidon_tree_benchmark.rs
+++ b/rln/benches/poseidon_tree_benchmark.rs
@@ -0,0 +1,79 @@
+use criterion::{criterion_group, criterion_main, BenchmarkId, Criterion};
+use rln::{
+    circuit::{Fr, TEST_TREE_HEIGHT},
+    hashers::PoseidonHash,
+};
+use utils::{FullMerkleTree, OptimalMerkleTree, ZerokitMerkleTree};
+
+pub fn get_leaves(n: u32) -> Vec<Fr> {
+    (0..n).map(|s| Fr::from(s)).collect()
+}
+
+pub fn optimal_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
+    c.bench_function("OptimalMerkleTree::<Poseidon>::full_height_gen", |b| {
+        b.iter(|| {
+            OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+        })
+    });
+
+    let mut group = c.benchmark_group("Set");
+    for &n in [1u32, 10, 100].iter() {
+        let leaves = get_leaves(n);
+
+        let mut tree = OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+        group.bench_function(
+            BenchmarkId::new("OptimalMerkleTree::<Poseidon>::set", n),
+            |b| {
+                b.iter(|| {
+                    for (i, l) in leaves.iter().enumerate() {
+                        let _ = tree.set(i, *l);
+                    }
+                })
+            },
+        );
+
+        group.bench_function(
+            BenchmarkId::new("OptimalMerkleTree::<Poseidon>::set_range", n),
+            |b| b.iter(|| tree.set_range(0, leaves.iter().cloned())),
+        );
+    }
+    group.finish();
+}
+
+pub fn full_merkle_tree_poseidon_benchmark(c: &mut Criterion) {
+    c.bench_function("FullMerkleTree::<Poseidon>::full_height_gen", |b| {
+        b.iter(|| {
+            FullMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+        })
+    });
+
+    let mut group = c.benchmark_group("Set");
+    for &n in [1u32, 10, 100].iter() {
+        let leaves = get_leaves(n);
+
+        let mut tree = FullMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+        group.bench_function(
+            BenchmarkId::new("FullMerkleTree::<Poseidon>::set", n),
+            |b| {
+                b.iter(|| {
+                    for (i, l) in leaves.iter().enumerate() {
+                        let _ = tree.set(i, *l);
+                    }
+                })
+            },
+        );
+
+        group.bench_function(
+            BenchmarkId::new("FullMerkleTree::<Poseidon>::set_range", n),
+            |b| b.iter(|| tree.set_range(0, leaves.iter().cloned())),
+        );
+    }
+    group.finish();
+}
+
+criterion_group!(
+    benches,
+    optimal_merkle_tree_poseidon_benchmark,
+    full_merkle_tree_poseidon_benchmark
+);
+criterion_main!(benches);
--- a/rln/resources/tree_height_15/rln.wasm
+++ b/rln/resources/tree_height_15/rln.wasm
--- a/rln/resources/tree_height_15/rln_final.zkey
+++ b/rln/resources/tree_height_15/rln_final.zkey
--- a/rln/resources/tree_height_15/verification_key.json
+++ b/rln/resources/tree_height_15/verification_key.json
@@ -1,119 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 6,
- "vk_alpha_1": [
-  "20124996762962216725442980738609010303800849578410091356605067053491763969391",
-  "9118593021526896828671519912099489027245924097793322973632351264852174143923",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "4693952934005375501364248788849686435240706020501681709396105298107971354382",
-   "14346958885444710485362620645446987998958218205939139994511461437152241966681"
-  ],
-  [
-   "16851772916911573982706166384196538392731905827088356034885868448550849804972",
-   "823612331030938060799959717749043047845343400798220427319188951998582076532"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "1361919643088555407518565462732544232965454074504004321739078395285189557133",
-   "20823246840633598579879223919854294301857184404415306521912631074982696570306"
-  ],
-  [
-   "7088590198103342249937795923142619828109070290720888704402714617857746884833",
-   "8191367139632195506244169264298620546181137131063303219908889318280111188437"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "12608968655665301215455851857466367636344427685631271961542642719683786103711",
-    "9849575605876329747382930567422916152871921500826003490242628251047652318086"
-   ],
-   [
-    "6322029441245076030714726551623552073612922718416871603535535085523083939021",
-    "8700115492541474338049149013125102281865518624059015445617546140629435818912"
-   ],
-   [
-    "10674973475340072635573101639867487770811074181475255667220644196793546640210",
-    "2926286967251299230490668407790788696102889214647256022788211245826267484824"
-   ]
-  ],
-  [
-   [
-    "9660441540778523475944706619139394922744328902833875392144658911530830074820",
-    "19548113127774514328631808547691096362144426239827206966690021428110281506546"
-   ],
-   [
-    "1870837942477655969123169532603615788122896469891695773961478956740992497097",
-    "12536105729661705698805725105036536744930776470051238187456307227425796690780"
-   ],
-   [
-    "21811903352654147452884857281720047789720483752548991551595462057142824037334",
-    "19021616763967199151052893283384285352200445499680068407023236283004353578353"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "17643142412395322664866141827318671249236739056291610144830020671604112279111",
-   "13273439661778801509295280274403992505521239023074387826870538372514206268318",
-   "1"
-  ],
-  [
-   "12325966053136615826793633393742326952102053533176311103856731330114882211366",
-   "6439956820140153832120005353467272867287237423425778281905068783317736451260",
-   "1"
-  ],
-  [
-   "20405310272367450124741832665322768131899487413829191383721623069139009993137",
-   "21336772016824870564600007750206596010566056069977718959140462128560786193566",
-   "1"
-  ],
-  [
-   "4007669092231576644992949839487535590075070172447826102934640178940614212519",
-   "7597503385395289202372182678960254605827199004598882158153019657732525465207",
-   "1"
-  ],
-  [
-   "4545695279389338758267531646940033299700127241196839077811942492841603458462",
-   "6635771967009274882904456432128877995932122611166121203658485990305433499873",
-   "1"
-  ],
-  [
-   "7876954805169515500747828488548350352651069599547377092970620945851311591012",
-   "7571431725691513008054581132582771105743462534789373657638701712901679323321",
-   "1"
-  ],
-  [
-   "5563973122249220346301217166900152021860462617567141574881706390202619333219",
-   "5147729144109676590873823097632042430451708874867871369293332620382492068692",
-   "1"
-  ]
- ]
-}
--- a/rln/resources/tree_height_19/rln.wasm
+++ b/rln/resources/tree_height_19/rln.wasm
--- a/rln/resources/tree_height_19/rln_final.zkey
+++ b/rln/resources/tree_height_19/rln_final.zkey
--- a/rln/resources/tree_height_19/verification_key.json
+++ b/rln/resources/tree_height_19/verification_key.json
@@ -1,119 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 6,
- "vk_alpha_1": [
-  "20124996762962216725442980738609010303800849578410091356605067053491763969391",
-  "9118593021526896828671519912099489027245924097793322973632351264852174143923",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "4693952934005375501364248788849686435240706020501681709396105298107971354382",
-   "14346958885444710485362620645446987998958218205939139994511461437152241966681"
-  ],
-  [
-   "16851772916911573982706166384196538392731905827088356034885868448550849804972",
-   "823612331030938060799959717749043047845343400798220427319188951998582076532"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "16125279975606773676640811113051624654121459921695914044301154938920321009721",
-   "14844345250267029614093295465313288254479124604567709177260777529651293576873"
-  ],
-  [
-   "20349277326920398483890518242229158117668855310237215044647746783223259766294",
-   "19338776107510040969200058390413661029003750817172740054990168933780935479540"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "12608968655665301215455851857466367636344427685631271961542642719683786103711",
-    "9849575605876329747382930567422916152871921500826003490242628251047652318086"
-   ],
-   [
-    "6322029441245076030714726551623552073612922718416871603535535085523083939021",
-    "8700115492541474338049149013125102281865518624059015445617546140629435818912"
-   ],
-   [
-    "10674973475340072635573101639867487770811074181475255667220644196793546640210",
-    "2926286967251299230490668407790788696102889214647256022788211245826267484824"
-   ]
-  ],
-  [
-   [
-    "9660441540778523475944706619139394922744328902833875392144658911530830074820",
-    "19548113127774514328631808547691096362144426239827206966690021428110281506546"
-   ],
-   [
-    "1870837942477655969123169532603615788122896469891695773961478956740992497097",
-    "12536105729661705698805725105036536744930776470051238187456307227425796690780"
-   ],
-   [
-    "21811903352654147452884857281720047789720483752548991551595462057142824037334",
-    "19021616763967199151052893283384285352200445499680068407023236283004353578353"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "5645604624116784480262312750033349186912223090668673154853165165224747369512",
-   "5656337658385597582701340925622307146226708710361427687425735166776477641124",
-   "1"
-  ],
-  [
-   "8216930132302312821663833393171053651364962198587857550991047765311607638330",
-   "19934865864074163318938688021560358348660709566570123384268356491416384822148",
-   "1"
-  ],
-  [
-   "11046959016591768534564223076484566731774575511709349452804727872479525392631",
-   "9401797690410912638766111919371607085248054251975419812613989999345815833269",
-   "1"
-  ],
-  [
-   "13216594148914395028254776738842380005944817065680915990743659996725367876414",
-   "11541283802841111343960351782994043892623551381569479006737253908665900144087",
-   "1"
-  ],
-  [
-   "6957074593219251760608960101283708711892008557897337713430173510328411964571",
-   "21673833055087220750009279957462375662312260098732685145862504142183400549467",
-   "1"
-  ],
-  [
-   "20795071270535109448604057031148356571036039566776607847840379441839742201050",
-   "21654952744643117202636583766828639581880877547772465264383291983528268115687",
-   "1"
-  ],
-  [
-   "19143058772755719660075704757531991493801758701561469885274062297246796623789",
-   "3996020163280925980543600106196205910576345230982361007978823537163123181007",
-   "1"
-  ]
- ]
-}
--- a/rln/resources/tree_height_20/graph.bin
+++ b/rln/resources/tree_height_20/graph.bin
--- a/rln/resources/tree_height_20/rln.wasm
+++ b/rln/resources/tree_height_20/rln.wasm
--- a/rln/resources/tree_height_20/rln_final.arkzkey
+++ b/rln/resources/tree_height_20/rln_final.arkzkey
--- a/rln/resources/tree_height_20/rln_final.zkey
+++ b/rln/resources/tree_height_20/rln_final.zkey
--- a/rln/resources/tree_height_20/verification_key.json
+++ b/rln/resources/tree_height_20/verification_key.json
@@ -1,119 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 6,
- "vk_alpha_1": [
-  "20124996762962216725442980738609010303800849578410091356605067053491763969391",
-  "9118593021526896828671519912099489027245924097793322973632351264852174143923",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "4693952934005375501364248788849686435240706020501681709396105298107971354382",
-   "14346958885444710485362620645446987998958218205939139994511461437152241966681"
-  ],
-  [
-   "16851772916911573982706166384196538392731905827088356034885868448550849804972",
-   "823612331030938060799959717749043047845343400798220427319188951998582076532"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "8353516066399360694538747105302262515182301251524941126222712285088022964076",
-   "9329524012539638256356482961742014315122377605267454801030953882967973561832"
-  ],
-  [
-   "16805391589556134376869247619848130874761233086443465978238468412168162326401",
-   "10111259694977636294287802909665108497237922060047080343914303287629927847739"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "12608968655665301215455851857466367636344427685631271961542642719683786103711",
-    "9849575605876329747382930567422916152871921500826003490242628251047652318086"
-   ],
-   [
-    "6322029441245076030714726551623552073612922718416871603535535085523083939021",
-    "8700115492541474338049149013125102281865518624059015445617546140629435818912"
-   ],
-   [
-    "10674973475340072635573101639867487770811074181475255667220644196793546640210",
-    "2926286967251299230490668407790788696102889214647256022788211245826267484824"
-   ]
-  ],
-  [
-   [
-    "9660441540778523475944706619139394922744328902833875392144658911530830074820",
-    "19548113127774514328631808547691096362144426239827206966690021428110281506546"
-   ],
-   [
-    "1870837942477655969123169532603615788122896469891695773961478956740992497097",
-    "12536105729661705698805725105036536744930776470051238187456307227425796690780"
-   ],
-   [
-    "21811903352654147452884857281720047789720483752548991551595462057142824037334",
-    "19021616763967199151052893283384285352200445499680068407023236283004353578353"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "11992897507809711711025355300535923222599547639134311050809253678876341466909",
-   "17181525095924075896332561978747020491074338784673526378866503154966799128110",
-   "1"
-  ],
-  [
-   "17018665030246167677911144513385572506766200776123272044534328594850561667818",
-   "18601114175490465275436712413925513066546725461375425769709566180981674884464",
-   "1"
-  ],
-  [
-   "18799470100699658367834559797874857804183288553462108031963980039244731716542",
-   "13064227487174191981628537974951887429496059857753101852163607049188825592007",
-   "1"
-  ],
-  [
-   "17432501889058124609368103715904104425610382063762621017593209214189134571156",
-   "13406815149699834788256141097399354592751313348962590382887503595131085938635",
-   "1"
-  ],
-  [
-   "10320964835612716439094703312987075811498239445882526576970512041988148264481",
-   "9024164961646353611176283204118089412001502110138072989569118393359029324867",
-   "1"
-  ],
-  [
-   "718355081067365548229685160476620267257521491773976402837645005858953849298",
-   "14635482993933988261008156660773180150752190597753512086153001683711587601974",
-   "1"
-  ],
-  [
-   "11777720285956632126519898515392071627539405001940313098390150593689568177535",
-   "8483603647274280691250972408211651407952870456587066148445913156086740744515",
-   "1"
-  ]
- ]
-}
--- a/rln/src/circuit.rs
+++ b/rln/src/circuit.rs
@@ -1,268 +0,0 @@
-// This crate provides interfaces for the zero-knowledge circuit and keys
-
-use ark_bn254::{
-    Bn254, Fq as ArkFq, Fq2 as ArkFq2, Fr as ArkFr, G1Affine as ArkG1Affine,
-    G1Projective as ArkG1Projective, G2Affine as ArkG2Affine, G2Projective as ArkG2Projective,
-};
-use ark_circom::read_zkey;
-use ark_groth16::{ProvingKey, VerifyingKey};
-use ark_relations::r1cs::ConstraintMatrices;
-use cfg_if::cfg_if;
-use color_eyre::{Report, Result};
-use num_bigint::BigUint;
-use serde_json::Value;
-use std::io::Cursor;
-use std::str::FromStr;
-
-cfg_if! {
-    if #[cfg(not(target_arch = "wasm32"))] {
-        use ark_circom::{WitnessCalculator};
-        use once_cell::sync::OnceCell;
-        use std::sync::Mutex;
-        use wasmer::{Module, Store};
-        use include_dir::{include_dir, Dir};
-        use std::path::Path;
-    }
-}
-
-const ZKEY_FILENAME: &str = "rln_final.zkey";
-const VK_FILENAME: &str = "verification_key.json";
-const WASM_FILENAME: &str = "rln.wasm";
-
-// These parameters are used for tests
-// Note that the circuit and keys in TEST_RESOURCES_FOLDER are compiled for Merkle trees of height 15, 19 and 20
-// Changing these parameters to other values than these defaults will cause zkSNARK proof verification to fail
-pub const TEST_PARAMETERS_INDEX: usize = 2;
-pub const TEST_TREE_HEIGHT: usize = [15, 19, 20][TEST_PARAMETERS_INDEX];
-pub const TEST_RESOURCES_FOLDER: &str =
-    ["tree_height_15", "tree_height_19", "tree_height_20"][TEST_PARAMETERS_INDEX];
-
-#[cfg(not(target_arch = "wasm32"))]
-static RESOURCES_DIR: Dir<'_> = include_dir!("$CARGO_MANIFEST_DIR/resources");
-
-// The following types define the pairing friendly elliptic curve, the underlying finite fields and groups default to this module
-// Note that proofs are serialized assuming Fr to be 4x8 = 32 bytes in size. Hence, changing to a curve with different encoding will make proof verification to fail
-pub type Curve = Bn254;
-pub type Fr = ArkFr;
-pub type Fq = ArkFq;
-pub type Fq2 = ArkFq2;
-pub type G1Affine = ArkG1Affine;
-pub type G1Projective = ArkG1Projective;
-pub type G2Affine = ArkG2Affine;
-pub type G2Projective = ArkG2Projective;
-
-// Loads the proving key using a bytes vector
-pub fn zkey_from_raw(zkey_data: &Vec<u8>) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
-    if !zkey_data.is_empty() {
-        let mut c = Cursor::new(zkey_data);
-        let proving_key_and_matrices = read_zkey(&mut c)?;
-        Ok(proving_key_and_matrices)
-    } else {
-        Err(Report::msg("No proving key found!"))
-    }
-}
-
-// Loads the proving key
-#[cfg(not(target_arch = "wasm32"))]
-pub fn zkey_from_folder(
-    resources_folder: &str,
-) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
-    let zkey = RESOURCES_DIR.get_file(Path::new(resources_folder).join(ZKEY_FILENAME));
-    if let Some(zkey) = zkey {
-        let mut c = Cursor::new(zkey.contents());
-        let proving_key_and_matrices = read_zkey(&mut c)?;
-        Ok(proving_key_and_matrices)
-    } else {
-        Err(Report::msg("No proving key found!"))
-    }
-}
-
-// Loads the verification key from a bytes vector
-pub fn vk_from_raw(vk_data: &Vec<u8>, zkey_data: &Vec<u8>) -> Result<VerifyingKey<Curve>> {
-    let verifying_key: VerifyingKey<Curve>;
-
-    if !vk_data.is_empty() {
-        verifying_key = vk_from_vector(vk_data)?;
-        Ok(verifying_key)
-    } else if !zkey_data.is_empty() {
-        let (proving_key, _matrices) = zkey_from_raw(zkey_data)?;
-        verifying_key = proving_key.vk;
-        Ok(verifying_key)
-    } else {
-        Err(Report::msg("No proving/verification key found!"))
-    }
-}
-
-// Loads the verification key
-#[cfg(not(target_arch = "wasm32"))]
-pub fn vk_from_folder(resources_folder: &str) -> Result<VerifyingKey<Curve>> {
-    let vk = RESOURCES_DIR.get_file(Path::new(resources_folder).join(VK_FILENAME));
-    let zkey = RESOURCES_DIR.get_file(Path::new(resources_folder).join(ZKEY_FILENAME));
-
-    let verifying_key: VerifyingKey<Curve>;
-    if let Some(vk) = vk {
-        verifying_key = vk_from_json(vk.contents_utf8().ok_or(Report::msg(
-            "Could not read verification key from JSON file!",
-        ))?)?;
-        Ok(verifying_key)
-    } else if let Some(_zkey) = zkey {
-        let (proving_key, _matrices) = zkey_from_folder(resources_folder)?;
-        verifying_key = proving_key.vk;
-        Ok(verifying_key)
-    } else {
-        Err(Report::msg("No proving/verification key found!"))
-    }
-}
-
-#[cfg(not(target_arch = "wasm32"))]
-static WITNESS_CALCULATOR: OnceCell<Mutex<WitnessCalculator>> = OnceCell::new();
-
-// Initializes the witness calculator using a bytes vector
-#[cfg(not(target_arch = "wasm32"))]
-pub fn circom_from_raw(wasm_buffer: Vec<u8>) -> Result<&'static Mutex<WitnessCalculator>> {
-    WITNESS_CALCULATOR.get_or_try_init(|| {
-        let store = Store::default();
-        let module = Module::new(&store, wasm_buffer)?;
-        let result = WitnessCalculator::from_module(module)?;
-        Ok::<Mutex<WitnessCalculator>, Report>(Mutex::new(result))
-    })
-}
-
-// Initializes the witness calculator
-#[cfg(not(target_arch = "wasm32"))]
-pub fn circom_from_folder(resources_folder: &str) -> Result<&'static Mutex<WitnessCalculator>> {
-    // We read the wasm file
-    let wasm = RESOURCES_DIR.get_file(Path::new(resources_folder).join(WASM_FILENAME));
-
-    if let Some(wasm) = wasm {
-        let wasm_buffer = wasm.contents();
-        circom_from_raw(wasm_buffer.to_vec())
-    } else {
-        Err(Report::msg("No wasm file found!"))
-    }
-}
-
-// The following function implementations are taken/adapted from https://github.com/gakonst/ark-circom/blob/1732e15d6313fe176b0b1abb858ac9e095d0dbd7/src/zkey.rs
-
-// Utilities to convert a json verification key in a groth16::VerificationKey
-fn fq_from_str(s: &str) -> Result<Fq> {
-    Ok(Fq::try_from(BigUint::from_str(s)?)?)
-}
-
-// Extracts the element in G1 corresponding to its JSON serialization
-fn json_to_g1(json: &Value, key: &str) -> Result<G1Affine> {
-    let els: Vec<String> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| i.as_str().ok_or(Report::msg("element is not a string")))
-        .map(|x| x.map(|v| v.to_owned()))
-        .collect::<Result<Vec<String>>>()?;
-
-    Ok(G1Affine::from(G1Projective::new(
-        fq_from_str(&els[0])?,
-        fq_from_str(&els[1])?,
-        fq_from_str(&els[2])?,
-    )))
-}
-
-// Extracts the vector of G1 elements corresponding to its JSON serialization
-fn json_to_g1_vec(json: &Value, key: &str) -> Result<Vec<G1Affine>> {
-    let els: Vec<Vec<String>> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| {
-            i.as_array()
-                .ok_or(Report::msg("element is not an array"))
-                .and_then(|array| {
-                    array
-                        .iter()
-                        .map(|x| x.as_str().ok_or(Report::msg("element is not a string")))
-                        .map(|x| x.map(|v| v.to_owned()))
-                        .collect::<Result<Vec<String>>>()
-                })
-        })
-        .collect::<Result<Vec<Vec<String>>>>()?;
-
-    let mut res = vec![];
-    for coords in els {
-        res.push(G1Affine::from(G1Projective::new(
-            fq_from_str(&coords[0])?,
-            fq_from_str(&coords[1])?,
-            fq_from_str(&coords[2])?,
-        )))
-    }
-
-    Ok(res)
-}
-
-// Extracts the element in G2 corresponding to its JSON serialization
-fn json_to_g2(json: &Value, key: &str) -> Result<G2Affine> {
-    let els: Vec<Vec<String>> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| {
-            i.as_array()
-                .ok_or(Report::msg("element is not an array"))
-                .and_then(|array| {
-                    array
-                        .iter()
-                        .map(|x| x.as_str().ok_or(Report::msg("element is not a string")))
-                        .map(|x| x.map(|v| v.to_owned()))
-                        .collect::<Result<Vec<String>>>()
-                })
-        })
-        .collect::<Result<Vec<Vec<String>>>>()?;
-
-    let x = Fq2::new(fq_from_str(&els[0][0])?, fq_from_str(&els[0][1])?);
-    let y = Fq2::new(fq_from_str(&els[1][0])?, fq_from_str(&els[1][1])?);
-    let z = Fq2::new(fq_from_str(&els[2][0])?, fq_from_str(&els[2][1])?);
-    Ok(G2Affine::from(G2Projective::new(x, y, z)))
-}
-
-// Converts JSON to a VerifyingKey
-fn to_verifying_key(json: serde_json::Value) -> Result<VerifyingKey<Curve>> {
-    Ok(VerifyingKey {
-        alpha_g1: json_to_g1(&json, "vk_alpha_1")?,
-        beta_g2: json_to_g2(&json, "vk_beta_2")?,
-        gamma_g2: json_to_g2(&json, "vk_gamma_2")?,
-        delta_g2: json_to_g2(&json, "vk_delta_2")?,
-        gamma_abc_g1: json_to_g1_vec(&json, "IC")?,
-    })
-}
-
-// Computes the verification key from its JSON serialization
-fn vk_from_json(vk: &str) -> Result<VerifyingKey<Curve>> {
-    let json: Value = serde_json::from_str(vk)?;
-    to_verifying_key(json)
-}
-
-// Computes the verification key from a bytes vector containing its JSON serialization
-fn vk_from_vector(vk: &[u8]) -> Result<VerifyingKey<Curve>> {
-    let json = String::from_utf8(vk.to_vec())?;
-    let json: Value = serde_json::from_str(&json)?;
-
-    to_verifying_key(json)
-}
-
-// Checks verification key to be correct with respect to proving key
-#[cfg(not(target_arch = "wasm32"))]
-pub fn check_vk_from_zkey(
-    resources_folder: &str,
-    verifying_key: VerifyingKey<Curve>,
-) -> Result<()> {
-    let (proving_key, _matrices) = zkey_from_folder(resources_folder)?;
-    if proving_key.vk == verifying_key {
-        Ok(())
-    } else {
-        Err(Report::msg("verifying_keys are not equal"))
-    }
-}
--- a/rln/src/circuit/iden3calc.rs
+++ b/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
+}
--- a/rln/src/circuit/iden3calc/graph.rs
+++ b/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::{BitAnd, BitOr, BitXor, 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);
+    }
+}
--- a/rln/src/circuit/iden3calc/proto.rs
+++ b/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,
+}
--- a/rln/src/circuit/iden3calc/storage.rs
+++ b/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);
+    }
+}
--- a/rln/src/circuit/mod.rs
+++ b/rln/src/circuit/mod.rs
@@ -0,0 +1,161 @@
+// This crate provides interfaces for the zero-knowledge circuit and keys
+
+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 color_eyre::{Report, Result};
+
+use crate::circuit::iden3calc::calc_witness;
+
+#[cfg(feature = "arkzkey")]
+use {
+    ark_ff::Field, ark_serialize::CanonicalDeserialize, ark_serialize::CanonicalSerialize,
+    color_eyre::eyre::WrapErr,
+};
+
+#[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>)> {
+    if zkey_data.is_empty() {
+        return Err(Report::msg("No proving key found!"));
+    }
+
+    let proving_key_and_matrices = match () {
+        #[cfg(feature = "arkzkey")]
+        () => read_arkzkey_from_bytes_uncompressed(zkey_data)?,
+        #[cfg(not(feature = "arkzkey"))]
+        () => {
+            let mut reader = Cursor::new(zkey_data);
+            read_zkey(&mut reader)?
+        }
+    };
+
+    Ok(proving_key_and_matrices)
+}
+
+// Loads the proving key
+#[cfg(not(target_arch = "wasm32"))]
+pub fn zkey_from_folder() -> &'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>)> {
+    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))
+}
--- a/rln/src/circuit/qap.rs
+++ b/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())
+    }
+}
--- a/rln/src/circuit/zkey.rs
+++ b/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()
+}
--- a/rln/src/ffi.rs
+++ b/rln/src/ffi.rs
@@ -8,11 +8,20 @@ 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)*) => {
        {
            let new_instance: &mut RLN = $instance.process();
-            new_instance.$method($($arg.process()),*).is_ok()
+            match new_instance.$method($($arg.process()),*) {
+                Ok(()) => {
+                    true
+                }
+                Err(err) => {
+                    eprintln!("execution error: {err}");
+                    false
+                }
+            }
        }
    }
 }
@@ -30,13 +39,17 @@ macro_rules! call_with_output_arg {
        {
            let mut output_data: Vec<u8> = Vec::new();
            let new_instance = $instance.process();
-            if new_instance.$method(&mut output_data).is_ok() {
-                unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                std::mem::forget(output_data);
-                true
-            } else {
-                std::mem::forget(output_data);
-                false
+            match new_instance.$method(&mut output_data) {
+                Ok(()) => {
+                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
+                    std::mem::forget(output_data);
+                    true
+                }
+                Err(err) => {
+                    std::mem::forget(output_data);
+                    eprintln!("execution error: {err}");
+                    false
+                }
            }
        }
    };
@@ -44,13 +57,17 @@ macro_rules! call_with_output_arg {
        {
            let mut output_data: Vec<u8> = Vec::new();
            let new_instance = $instance.process();
-            if new_instance.$method($($arg.process()),*, &mut output_data).is_ok() {
-                unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                std::mem::forget(output_data);
-                true
-            } else {
-                std::mem::forget(output_data);
-                false
+            match new_instance.$method($($arg.process()),*, &mut output_data) {
+                Ok(()) => {
+                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
+                    std::mem::forget(output_data);
+                    true
+                }
+                Err(err) => {
+                    std::mem::forget(output_data);
+                    eprintln!("execution error: {err}");
+                    false
+                }
            }
        }
    };
@@ -66,13 +83,17 @@ macro_rules! no_ctx_call_with_output_arg {
    ($method:ident, $output_arg:expr, $( $arg:expr ),* ) => {
        {
            let mut output_data: Vec<u8> = Vec::new();
-            if $method($($arg.process()),*, &mut output_data).is_ok() {
-                unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                std::mem::forget(output_data);
-                true
-            } else {
-                std::mem::forget(output_data);
-                false
+            match $method($($arg.process()),*, &mut output_data) {
+                Ok(()) => {
+                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
+                    std::mem::forget(output_data);
+                    true
+                }
+                Err(err) => {
+                    std::mem::forget(output_data);
+                    eprintln!("execution error: {err}");
+                    false
+                }
            }
        }
    }
@@ -89,8 +110,11 @@ macro_rules! call_with_bool_arg {
        {
            let new_instance = $instance.process();
            if match new_instance.$method($($arg.process()),*,) {
-                Ok(verified) => verified,
-                Err(_) => return false,
+                Ok(result) => result,
+                Err(err) => {
+                    eprintln!("execution error: {err}");
+                    return false
+                },
            } {
                unsafe { *$bool_arg = true };
            } else {
@@ -120,24 +144,24 @@ impl ProcessArg for *const Buffer {
    }
 }

-impl<'a> ProcessArg for *const RLN<'a> {
-    type ReturnType = &'a RLN<'a>;
+impl ProcessArg for *const RLN {
+    type ReturnType = &'static RLN;
    fn process(self) -> Self::ReturnType {
        unsafe { &*self }
    }
 }

-impl<'a> ProcessArg for *mut RLN<'a> {
-    type ReturnType = &'a mut RLN<'a>;
+impl ProcessArg for *mut RLN {
+    type ReturnType = &'static mut RLN;
    fn process(self) -> Self::ReturnType {
        unsafe { &mut *self }
    }
 }

-/// Buffer struct is taken from
-/// <https://github.com/celo-org/celo-threshold-bls-rs/blob/master/crates/threshold-bls-ffi/src/ffi.rs>
-///
-/// Also heavily inspired by <https://github.com/kilic/rln/blob/master/src/ffi.rs>
+///// Buffer struct is taken from
+///// <https://github.com/celo-org/celo-threshold-bls-rs/blob/master/crates/threshold-bls-ffi/src/ffi.rs>
+/////
+///// Also heavily inspired by <https://github.com/kilic/rln/blob/master/src/ffi.rs>

 #[repr(C)]
 #[derive(Clone, Debug, PartialEq)]
@@ -169,35 +193,84 @@ impl<'a> From<&Buffer> for &'a [u8] {
 ////////////////////////////////////////////////////////

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(not(feature = "stateless"))]
 #[no_mangle]
 pub extern "C" fn new(tree_height: usize, input_buffer: *const Buffer, ctx: *mut *mut RLN) -> bool {
-    if let Ok(rln) = RLN::new(tree_height, input_buffer.process()) {
-        unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-        true
-    } else {
-        false
+    match RLN::new(tree_height, input_buffer.process()) {
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
    }
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(feature = "stateless")]
+#[no_mangle]
+pub extern "C" fn new(ctx: *mut *mut RLN) -> bool {
+    match RLN::new() {
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
+    }
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(not(feature = "stateless"))]
 #[no_mangle]
 pub extern "C" fn new_with_params(
    tree_height: usize,
-    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 {
-    if let Ok(rln) = RLN::new_with_params(
+    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(),
    ) {
-        unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-        true
-    } else {
-        false
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
+    }
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(feature = "stateless")]
+#[no_mangle]
+pub extern "C" fn new_with_params(
+    zkey_buffer: *const Buffer,
+    graph_buffer: *const Buffer,
+    ctx: *mut *mut RLN,
+) -> bool {
+    match RLN::new_with_params(
+        zkey_buffer.process().to_vec(),
+        graph_buffer.process().to_vec(),
+    ) {
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
    }
 }

@@ -206,36 +279,49 @@ pub extern "C" fn new_with_params(
 ////////////////////////////////////////////////////////
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_tree(ctx: *mut RLN, tree_height: usize) -> bool {
    call!(ctx, set_tree, tree_height)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn delete_leaf(ctx: *mut RLN, index: usize) -> bool {
    call!(ctx, delete_leaf, index)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_leaf(ctx: *mut RLN, index: usize, input_buffer: *const Buffer) -> bool {
    call!(ctx, set_leaf, index, input_buffer)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_leaf(ctx: *mut RLN, index: usize, output_buffer: *mut Buffer) -> bool {
    call_with_output_arg!(ctx, get_leaf, output_buffer, index)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
+pub extern "C" fn leaves_set(ctx: *mut RLN) -> usize {
+    ctx.process().leaves_set()
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_next_leaf(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
    call!(ctx, set_next_leaf, input_buffer)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_leaves_from(
    ctx: *mut RLN,
    index: usize,
@@ -246,12 +332,14 @@ pub extern "C" fn set_leaves_from(

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn init_tree_with_leaves(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
    call!(ctx, init_tree_with_leaves, input_buffer)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn atomic_operation(
    ctx: *mut RLN,
    index: usize,
@@ -263,12 +351,31 @@ pub extern "C" fn atomic_operation(

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
+pub extern "C" fn seq_atomic_operation(
+    ctx: *mut RLN,
+    leaves_buffer: *const Buffer,
+    indices_buffer: *const Buffer,
+) -> bool {
+    call!(
+        ctx,
+        atomic_operation,
+        ctx.process().leaves_set(),
+        leaves_buffer,
+        indices_buffer
+    )
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_root(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
    call_with_output_arg!(ctx, get_root, output_buffer)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_proof(ctx: *const RLN, index: usize, output_buffer: *mut Buffer) -> bool {
    call_with_output_arg!(ctx, get_proof, output_buffer, index)
 }
@@ -298,6 +405,7 @@ pub extern "C" fn verify(

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn generate_rln_proof(
    ctx: *mut RLN,
    input_buffer: *const Buffer,
@@ -308,6 +416,22 @@ pub extern "C" fn generate_rln_proof(

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+pub extern "C" fn generate_rln_proof_with_witness(
+    ctx: *mut RLN,
+    input_buffer: *const Buffer,
+    output_buffer: *mut Buffer,
+) -> bool {
+    call_with_output_arg!(
+        ctx,
+        generate_rln_proof_with_witness,
+        output_buffer,
+        input_buffer
+    )
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn verify_rln_proof(
    ctx: *const RLN,
    proof_buffer: *const Buffer,
@@ -391,18 +515,21 @@ pub extern "C" fn recover_id_secret(

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_metadata(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
    call!(ctx, set_metadata, input_buffer)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_metadata(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
    call_with_output_arg!(ctx, get_metadata, output_buffer)
 }

 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn flush(ctx: *mut RLN) -> bool {
    call!(ctx, flush)
 }
--- a/rln/src/hashers.rs
+++ b/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")
 }

--- a/rln/src/lib.rs
+++ b/rln/src/lib.rs
@@ -1,13 +1,12 @@
-#![allow(dead_code)]
-
 pub mod circuit;
+#[cfg(not(target_arch = "wasm32"))]
+pub mod ffi;
 pub mod hashers;
 #[cfg(feature = "pmtree-ft")]
 pub mod pm_tree_adapter;
 pub mod poseidon_tree;
 pub mod protocol;
 pub mod public;
+#[cfg(test)]
+pub mod public_api_tests;
 pub mod utils;
-
-#[cfg(not(target_arch = "wasm32"))]
-pub mod ffi;
--- a/rln/src/pm_tree_adapter.rs
+++ b/rln/src/pm_tree_adapter.rs
@@ -5,6 +5,7 @@ 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::*;

@@ -16,6 +17,9 @@ const METADATA_KEY: [u8; 8] = *b"metadata";

 pub struct PmTree {
    tree: pmtree::MerkleTree<SledDB, PoseidonHash>,
+    /// The indices of leaves which are set into zero upto next_index.
+    /// Set to 0 if the leaf is empty and set to 1 in otherwise.
+    cached_leaves_indices: Vec<u8>,
    // metadata that an application may use to store additional information
    metadata: Vec<u8>,
 }
@@ -143,6 +147,7 @@ impl ZerokitMerkleTree for PmTree {

        Ok(PmTree {
            tree,
+            cached_leaves_indices: vec![0; 1 << depth],
            metadata: Vec::new(),
        })
    }
@@ -155,7 +160,7 @@ impl ZerokitMerkleTree for PmTree {
        self.tree.capacity()
    }

-    fn leaves_set(&mut self) -> usize {
+    fn leaves_set(&self) -> usize {
        self.tree.leaves_set()
    }

@@ -170,7 +175,9 @@ impl ZerokitMerkleTree for PmTree {
    fn set(&mut self, index: usize, leaf: FrOf<Self::Hasher>) -> Result<()> {
        self.tree
            .set(index, leaf)
-            .map_err(|e| Report::msg(e.to_string()))
+            .map_err(|e| Report::msg(e.to_string()))?;
+        self.cached_leaves_indices[index] = 1;
+        Ok(())
    }

    fn set_range<I: IntoIterator<Item = FrOf<Self::Hasher>>>(
@@ -178,15 +185,51 @@ impl ZerokitMerkleTree for PmTree {
        start: usize,
        values: I,
    ) -> Result<()> {
+        let v = values.into_iter().collect::<Vec<_>>();
        self.tree
-            .set_range(start, values)
-            .map_err(|e| Report::msg(e.to_string()))
+            .set_range(start, v.clone().into_iter())
+            .map_err(|e| Report::msg(e.to_string()))?;
+        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_subtree_root(&self, n: usize, index: usize) -> Result<FrOf<Self::Hasher>> {
+        if n > self.depth() {
+            return Err(Report::msg("level exceeds depth size"));
+        }
+        if index >= self.capacity() {
+            return Err(Report::msg("index exceeds set size"));
+        }
+        if n == 0 {
+            Ok(self.root())
+        } else if n == self.depth() {
+            self.get(index)
+        } else {
+            let node = self
+                .tree
+                .get_elem(Key::new(n, index >> (self.depth() - n)))
+                .unwrap();
+            Ok(node)
+        }
+    }
+
+    fn get_empty_leaves_indices(&self) -> Vec<usize> {
+        let next_idx = self.leaves_set();
+        self.cached_leaves_indices
+            .iter()
+            .take(next_idx)
+            .enumerate()
+            .filter(|&(_, &v)| v == 0u8)
+            .map(|(idx, _)| idx)
+            .collect()
+    }
+
    fn override_range<I: IntoIterator<Item = FrOf<Self::Hasher>>, J: IntoIterator<Item = usize>>(
        &mut self,
        start: usize,
@@ -197,11 +240,13 @@ impl ZerokitMerkleTree for PmTree {
        let mut indices = indices.into_iter().collect::<Vec<_>>();
        indices.sort();

-        match (leaves.is_empty(), indices.is_empty()) {
-            (true, true) => Err(Report::msg("no leaves or indices to be removed")),
-            (false, true) => self.set_range_with_leaves(start, leaves),
-            (true, false) => self.remove_indices(indices),
-            (false, false) => self.remove_indices_and_set_leaves(start, leaves, indices),
+        match (leaves.len(), indices.len()) {
+            (0, 0) => Err(Report::msg("no leaves or indices to be removed")),
+            (1, 0) => self.set(start, leaves[0]),
+            (0, 1) => self.delete(indices[0]),
+            (_, 0) => self.set_range(start, leaves.into_iter()),
+            (0, _) => self.remove_indices(&indices),
+            (_, _) => self.remove_indices_and_set_leaves(start, leaves, &indices),
        }
    }

@@ -214,7 +259,9 @@ impl ZerokitMerkleTree for PmTree {
    fn delete(&mut self, index: usize) -> Result<()> {
        self.tree
            .delete(index)
-            .map_err(|e| Report::msg(e.to_string()))
+            .map_err(|e| Report::msg(e.to_string()))?;
+        self.cached_leaves_indices[index] = 0;
+        Ok(())
    }

    fn proof(&self, index: usize) -> Result<Self::Proof> {
@@ -244,7 +291,8 @@ impl ZerokitMerkleTree for PmTree {
        let data = self.tree.db.get(METADATA_KEY)?;

        if data.is_none() {
-            return Err(Report::msg("metadata does not exist"));
+            // send empty Metadata
+            return Ok(Vec::new());
        }
        Ok(data.unwrap())
    }
@@ -258,44 +306,33 @@ type PmTreeHasher = <PmTree as ZerokitMerkleTree>::Hasher;
 type FrOfPmTreeHasher = FrOf<PmTreeHasher>;

 impl PmTree {
-    fn set_range_with_leaves(&mut self, start: usize, leaves: Vec<FrOfPmTreeHasher>) -> Result<()> {
-        self.tree
-            .set_range(start, leaves)
-            .map_err(|e| Report::msg(e.to_string()))
-    }
-
-    fn remove_indices(&mut self, indices: Vec<usize>) -> Result<()> {
+    fn remove_indices(&mut self, indices: &[usize]) -> Result<()> {
        let start = indices[0];
        let end = indices.last().unwrap() + 1;

-        let mut new_leaves: Vec<_> = (start..end)
-            .map(|i| self.tree.get(i))
-            .collect::<Result<_, _>>()?;
-
-        new_leaves
-            .iter_mut()
-            .take(indices.len())
-            .for_each(|leaf| *leaf = PmTreeHasher::default_leaf());
+        let new_leaves = (start..end).map(|_| PmTreeHasher::default_leaf());

        self.tree
            .set_range(start, new_leaves)
-            .map_err(|e| Report::msg(e.to_string()))
+            .map_err(|e| Report::msg(e.to_string()))?;
+
+        for i in start..end {
+            self.cached_leaves_indices[i] = 0
+        }
+        Ok(())
    }

    fn remove_indices_and_set_leaves(
        &mut self,
        start: usize,
        leaves: Vec<FrOfPmTreeHasher>,
-        indices: Vec<usize>,
+        indices: &[usize],
    ) -> Result<()> {
        let min_index = *indices.first().unwrap();
        let max_index = start + leaves.len();

-        // Generated a placeholder with the exact size needed,
-        // Initiated with default values to be overridden throughout the method
        let mut set_values = vec![PmTreeHasher::default_leaf(); max_index - min_index];

-        // If the index is not in indices list, keep the original value
        for i in min_index..start {
            if !indices.contains(&i) {
                let value = self.tree.get(i)?;
@@ -303,14 +340,22 @@ impl PmTree {
            }
        }

-        // Insert new leaves after 'start' position
        for (i, &leaf) in leaves.iter().enumerate() {
            set_values[start - min_index + i] = leaf;
        }

        self.tree
-            .set_range(min_index, set_values)
-            .map_err(|e| Report::msg(e.to_string()))
+            .set_range(start, set_values)
+            .map_err(|e| Report::msg(e.to_string()))?;
+
+        for i in indices {
+            self.cached_leaves_indices[*i] = 0;
+        }
+
+        for i in start..(max_index - min_index) {
+            self.cached_leaves_indices[i] = 1
+        }
+        Ok(())
    }
 }

--- a/rln/src/protocol.rs
+++ b/rln/src/protocol.rs
@@ -1,42 +1,46 @@
 // This crate collects all the underlying primitives used to implement RLN

-use ark_circom::{CircomReduction, WitnessCalculator};
+use ark_bn254::Fr;
 use ark_groth16::{prepare_verifying_key, Groth16, Proof as ArkProof, ProvingKey, VerifyingKey};
-use ark_relations::r1cs::ConstraintMatrices;
-use ark_relations::r1cs::SynthesisError;
+use ark_relations::r1cs::{ConstraintMatrices, SynthesisError};
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
 use ark_std::{rand::thread_rng, UniformRand};
 use color_eyre::{Report, Result};
 use num_bigint::BigInt;
 use rand::{Rng, SeedableRng};
 use rand_chacha::ChaCha20Rng;
-#[cfg(not(target_arch = "wasm32"))]
-use std::sync::Mutex;
-#[cfg(debug_assertions)]
+use serde::{Deserialize, Serialize};
+#[cfg(test)]
 use std::time::Instant;
 use thiserror::Error;
 use tiny_keccak::{Hasher as _, Keccak};

-use crate::circuit::{Curve, Fr};
-use crate::hashers::hash_to_field;
-use crate::hashers::poseidon_hash;
+use crate::circuit::{calculate_rln_witness, qap::CircomReduction, Curve};
+use crate::hashers::{hash_to_field, poseidon_hash};
 use crate::poseidon_tree::*;
 use crate::public::RLN_IDENTIFIER;
 use crate::utils::*;
-use cfg_if::cfg_if;
 use utils::{ZerokitMerkleProof, ZerokitMerkleTree};

 ///////////////////////////////////////////////////////
 // RLN Witness data structure and utility functions
 ///////////////////////////////////////////////////////

-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
 pub struct RLNWitnessInput {
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
    identity_secret: Fr,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
+    user_message_limit: Fr,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
+    message_id: Fr,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
    path_elements: Vec<Fr>,
    identity_path_index: Vec<u8>,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
    x: Fr,
-    epoch: Fr,
-    rln_identifier: Fr,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
+    external_nullifier: Fr,
 }

 #[derive(Debug, PartialEq)]
@@ -47,8 +51,7 @@ pub struct RLNProofValues {
    pub root: Fr,
    // Public Inputs:
    pub x: Fr,
-    pub epoch: Fr,
-    pub rln_identifier: Fr,
+    pub external_nullifier: Fr,
 }

 pub fn serialize_field_element(element: Fr) -> Vec<u8> {
@@ -90,25 +93,54 @@ pub fn deserialize_identity_tuple(serialized: Vec<u8>) -> (Fr, Fr, Fr, Fr) {
    )
 }

+/// Serializes witness
+///
+/// # Errors
+///
+/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
+/// input data is [ identity_secret<32> | user_message_limit<32> | message_id<32> | path_elements[<32>] | identity_path_index<8> | x<32> | external_nullifier<32> ]
 pub fn serialize_witness(rln_witness: &RLNWitnessInput) -> Result<Vec<u8>> {
-    let mut serialized: Vec<u8> = Vec::new();
+    // Check if message_id is within user_message_limit
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;

-    serialized.append(&mut fr_to_bytes_le(&rln_witness.identity_secret));
-    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.epoch));
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.rln_identifier));
+    // Calculate capacity for Vec:
+    // - 5 fixed field elements: identity_secret, user_message_limit, message_id, x, external_nullifier
+    // - variable number of path elements
+    // - identity_path_index (variable size)
+    let mut serialized: Vec<u8> = Vec::with_capacity(
+        fr_byte_size() * (5 + rln_witness.path_elements.len())
+            + rln_witness.identity_path_index.len(),
+    );
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.identity_secret));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.user_message_limit));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.message_id));
+    serialized.extend_from_slice(&vec_fr_to_bytes_le(&rln_witness.path_elements)?);
+    serialized.extend_from_slice(&vec_u8_to_bytes_le(&rln_witness.identity_path_index)?);
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.x));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.external_nullifier));

    Ok(serialized)
 }

+/// Deserializes witness
+///
+/// # Errors
+///
+/// Returns an error if `message_id` is not within `user_message_limit`.
 pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)> {
    let mut all_read: usize = 0;

    let (identity_secret, read) = bytes_le_to_fr(&serialized[all_read..]);
    all_read += read;

+    let (user_message_limit, read) = bytes_le_to_fr(&serialized[all_read..]);
+    all_read += read;
+
+    let (message_id, read) = bytes_le_to_fr(&serialized[all_read..]);
+    all_read += read;
+
+    message_id_range_check(&message_id, &user_message_limit)?;
+
    let (path_elements, read) = bytes_le_to_vec_fr(&serialized[all_read..])?;
    all_read += read;

@@ -118,13 +150,9 @@ pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)
    let (x, read) = bytes_le_to_fr(&serialized[all_read..]);
    all_read += read;

-    let (epoch, read) = bytes_le_to_fr(&serialized[all_read..]);
+    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
    all_read += read;

-    let (rln_identifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    // TODO: check rln_identifier against public::RLN_IDENTIFIER
    if serialized.len() != all_read {
        return Err(Report::msg("serialized length is not equal to all_read"));
    }
@@ -135,8 +163,9 @@ pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)
            path_elements,
            identity_path_index,
            x,
-            epoch,
-            rln_identifier,
+            external_nullifier,
+            user_message_limit,
+            message_id,
        },
        all_read,
    ))
@@ -144,7 +173,7 @@ pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)

 // This function deserializes input for kilic's rln generate_proof public API
 // https://github.com/kilic/rln/blob/7ac74183f8b69b399e3bc96c1ae8ab61c026dc43/src/public.rs#L148
-// input_data is [ identity_secret<32> | id_index<8> | epoch<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> ]
 // return value is a rln witness populated according to this information
 pub fn proof_inputs_to_rln_witness(
    tree: &mut PoseidonTree,
@@ -160,7 +189,13 @@ pub fn proof_inputs_to_rln_witness(
    ))?;
    all_read += 8;

-    let (epoch, read) = bytes_le_to_fr(&serialized[all_read..]);
+    let (user_message_limit, read) = bytes_le_to_fr(&serialized[all_read..]);
+    all_read += read;
+
+    let (message_id, read) = bytes_le_to_fr(&serialized[all_read..]);
+    all_read += read;
+
+    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
    all_read += read;

    let signal_len = usize::try_from(u64::from_le_bytes(
@@ -176,83 +211,49 @@ pub fn proof_inputs_to_rln_witness(

    let x = hash_to_field(&signal);

-    let rln_identifier = hash_to_field(RLN_IDENTIFIER);
-
    Ok((
        RLNWitnessInput {
            identity_secret,
            path_elements,
            identity_path_index,
+            user_message_limit,
+            message_id,
            x,
-            epoch,
-            rln_identifier,
+            external_nullifier,
        },
        all_read,
    ))
 }

-pub fn rln_witness_from_json(input_json_str: &str) -> Result<RLNWitnessInput> {
-    let input_json: serde_json::Value =
-        serde_json::from_str(input_json_str).expect("JSON was not well-formatted");
+/// Creates [`RLNWitnessInput`] from it's fields.
+///
+/// # Errors
+///
+/// Returns an error if `message_id` is not within `user_message_limit`.
+pub fn rln_witness_from_values(
+    identity_secret: Fr,
+    merkle_proof: &MerkleProof,
+    x: Fr,
+    external_nullifier: Fr,
+    user_message_limit: Fr,
+    message_id: Fr,
+) -> Result<RLNWitnessInput> {
+    message_id_range_check(&message_id, &user_message_limit)?;

-    let identity_secret = str_to_fr(&input_json["identity_secret"].to_string(), 10)?;
-
-    let path_elements = input_json["path_elements"]
-        .as_array()
-        .ok_or(Report::msg("not an array"))?
-        .iter()
-        .map(|v| str_to_fr(&v.to_string(), 10))
-        .collect::<Result<_>>()?;
-
-    let identity_path_index_array = input_json["identity_path_index"]
-        .as_array()
-        .ok_or(Report::msg("not an arrray"))?;
-
-    let mut identity_path_index: Vec<u8> = vec![];
-
-    for v in identity_path_index_array {
-        identity_path_index.push(v.as_u64().ok_or(Report::msg("not a u64 value"))? as u8);
-    }
-
-    let x = str_to_fr(&input_json["x"].to_string(), 10)?;
-
-    let epoch = str_to_fr(&input_json["epoch"].to_string(), 16)?;
-
-    let rln_identifier = str_to_fr(&input_json["rln_identifier"].to_string(), 10)?;
-
-    // TODO: check rln_identifier against public::RLN_IDENTIFIER
+    let path_elements = merkle_proof.get_path_elements();
+    let identity_path_index = merkle_proof.get_path_index();

    Ok(RLNWitnessInput {
        identity_secret,
        path_elements,
        identity_path_index,
        x,
-        epoch,
-        rln_identifier,
+        external_nullifier,
+        user_message_limit,
+        message_id,
    })
 }

-pub fn rln_witness_from_values(
-    identity_secret: Fr,
-    merkle_proof: &MerkleProof,
-    x: Fr,
-    epoch: Fr,
-    //rln_identifier: Fr,
-) -> RLNWitnessInput {
-    let path_elements = merkle_proof.get_path_elements();
-    let identity_path_index = merkle_proof.get_path_index();
-    let rln_identifier = hash_to_field(RLN_IDENTIFIER);
-
-    RLNWitnessInput {
-        identity_secret,
-        path_elements,
-        identity_path_index,
-        x,
-        epoch,
-        rln_identifier,
-    }
-}
-
 pub fn random_rln_witness(tree_height: usize) -> RLNWitnessInput {
    let mut rng = thread_rng();

@@ -269,21 +270,26 @@ pub fn random_rln_witness(tree_height: usize) -> RLNWitnessInput {
        identity_path_index.push(rng.gen_range(0..2) as u8);
    }

+    let user_message_limit = Fr::from(100);
+    let message_id = Fr::from(1);
+
    RLNWitnessInput {
        identity_secret,
        path_elements,
        identity_path_index,
        x,
-        epoch,
-        rln_identifier,
+        external_nullifier: poseidon_hash(&[epoch, rln_identifier]),
+        user_message_limit,
+        message_id,
    }
 }

-pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> RLNProofValues {
+pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> Result<RLNProofValues> {
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
+
    // y share
-    let external_nullifier = poseidon_hash(&[rln_witness.epoch, rln_witness.rln_identifier]);
    let a_0 = rln_witness.identity_secret;
-    let a_1 = poseidon_hash(&[a_0, external_nullifier]);
+    let a_1 = poseidon_hash(&[a_0, rln_witness.external_nullifier, rln_witness.message_id]);
    let y = a_0 + rln_witness.x * a_1;

    // Nullifier
@@ -292,30 +298,31 @@ pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> RLNProofValue
    // Merkle tree root computations
    let root = compute_tree_root(
        &rln_witness.identity_secret,
+        &rln_witness.user_message_limit,
        &rln_witness.path_elements,
        &rln_witness.identity_path_index,
-        true,
    );

-    RLNProofValues {
+    Ok(RLNProofValues {
        y,
        nullifier,
        root,
        x: rln_witness.x,
-        epoch: rln_witness.epoch,
-        rln_identifier: rln_witness.rln_identifier,
-    }
+        external_nullifier: rln_witness.external_nullifier,
+    })
 }

+/// input_data is [ root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
 pub fn serialize_proof_values(rln_proof_values: &RLNProofValues) -> Vec<u8> {
-    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.epoch));
-    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.append(&mut fr_to_bytes_le(&rln_proof_values.rln_identifier));
+    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
 }
@@ -328,7 +335,7 @@ pub fn deserialize_proof_values(serialized: &[u8]) -> (RLNProofValues, usize) {
    let (root, read) = bytes_le_to_fr(&serialized[all_read..]);
    all_read += read;

-    let (epoch, read) = bytes_le_to_fr(&serialized[all_read..]);
+    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
    all_read += read;

    let (x, read) = bytes_le_to_fr(&serialized[all_read..]);
@@ -340,46 +347,55 @@ pub fn deserialize_proof_values(serialized: &[u8]) -> (RLNProofValues, usize) {
    let (nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
    all_read += read;

-    let (rln_identifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
    (
        RLNProofValues {
            y,
            nullifier,
            root,
            x,
-            epoch,
-            rln_identifier,
+            external_nullifier,
        },
        all_read,
    )
 }

+// input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
 pub fn prepare_prove_input(
    identity_secret: Fr,
    id_index: usize,
-    epoch: Fr,
+    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(&epoch));
-    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
 }
@@ -389,15 +405,13 @@ pub fn prepare_verify_input(proof_data: Vec<u8>, signal: &[u8]) -> Vec<u8> {
 ///////////////////////////////////////////////////////

 pub fn compute_tree_root(
-    leaf: &Fr,
+    identity_secret: &Fr,
+    user_message_limit: &Fr,
    path_elements: &[Fr],
    identity_path_index: &[u8],
-    hash_leaf: bool,
 ) -> Fr {
-    let mut root = *leaf;
-    if hash_leaf {
-        root = poseidon_hash(&[root]);
-    }
+    let id_commitment = poseidon_hash(&[*identity_secret]);
+    let mut root = poseidon_hash(&[id_commitment, *user_message_limit]);

    for i in 0..identity_path_index.len() {
        if identity_path_index[i] == 0 {
@@ -488,11 +502,7 @@ pub fn extended_seeded_keygen(signal: &[u8]) -> (Fr, Fr, Fr, Fr) {
    )
 }

-pub fn compute_id_secret(
-    share1: (Fr, Fr),
-    share2: (Fr, Fr),
-    external_nullifier: Fr,
-) -> Result<Fr, String> {
+pub fn compute_id_secret(share1: (Fr, Fr), share2: (Fr, Fr)) -> Result<Fr, String> {
    // Assuming a0 is the identity secret and a1 = poseidonHash([a0, external_nullifier]),
    // a (x,y) share satisfies the following relation
    // y = a_0 + x * a_1
@@ -506,14 +516,7 @@ pub fn compute_id_secret(
    let a_0 = y1 - x1 * a_1;

    // If shares come from the same polynomial, a0 is correctly recovered and a1 = poseidonHash([a0, external_nullifier])
-    let computed_a_1 = poseidon_hash(&[a_0, external_nullifier]);
-
-    if a_1 == computed_a_1 {
-        // We successfully recovered the identity secret
-        Ok(a_0)
-    } else {
-        Err("Cannot recover identity_secret_hash from provided shares".into())
-    }
+    Ok(a_0)
 }

 ///////////////////////////////////////////////////////
@@ -560,13 +563,13 @@ pub fn generate_proof_with_witness(
    proving_key: &(ProvingKey<Curve>, ConstraintMatrices<Fr>),
 ) -> Result<ArkProof<Curve>, ProofError> {
    // If in debug mode, we measure and later print time take to compute witness
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
    let now = Instant::now();

    let full_assignment =
        calculate_witness_element::<Curve>(witness).map_err(ProofError::WitnessError)?;

-    #[cfg(debug_assertions)]
+    #[cfg(test)]
    println!("witness generation took: {:.2?}", now.elapsed());

    // Random Values
@@ -575,7 +578,7 @@ 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(
@@ -588,42 +591,36 @@ pub fn generate_proof_with_witness(
        full_assignment.as_slice(),
    )?;

-    #[cfg(debug_assertions)]
+    #[cfg(test)]
    println!("proof generation took: {:.2?}", now.elapsed());

    Ok(proof)
 }

+/// Formats inputs for witness calculation
+///
+/// # Errors
+///
+/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
 pub fn inputs_for_witness_calculation(
    rln_witness: &RLNWitnessInput,
-) -> Result<[(&str, Vec<BigInt>); 6]> {
-    // We confert the path indexes to field elements
-    // TODO: check if necessary
-    let mut path_elements = Vec::new();
+) -> Result<[(&str, Vec<Fr>); 7]> {
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;

-    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([
-        (
-            "identity_secret",
-            vec![to_bigint(&rln_witness.identity_secret)?],
-        ),
-        ("path_elements", path_elements),
-        ("identity_path_index", identity_path_index),
-        ("x", vec![to_bigint(&rln_witness.x)?]),
-        ("epoch", vec![to_bigint(&rln_witness.epoch)?]),
-        (
-            "rln_identifier",
-            vec![to_bigint(&rln_witness.rln_identifier)?],
-        ),
+        ("identitySecret", vec![rln_witness.identity_secret]),
+        ("userMessageLimit", vec![rln_witness.user_message_limit]),
+        ("messageId", vec![rln_witness.message_id]),
+        ("pathElements", rln_witness.path_elements.clone()),
+        ("identityPathIndex", identity_path_index),
+        ("x", vec![rln_witness.x]),
+        ("externalNullifier", vec![rln_witness.external_nullifier]),
    ])
 }

@@ -633,34 +630,20 @@ 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
@@ -669,9 +652,8 @@ 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,
        r,
@@ -682,7 +664,7 @@ pub fn generate_proof(
        full_assignment.as_slice(),
    )?;

-    #[cfg(debug_assertions)]
+    #[cfg(test)]
    println!("proof generation took: {:.2?}", now.elapsed());

    Ok(proof)
@@ -705,8 +687,7 @@ pub fn verify_proof(
        proof_values.root,
        proof_values.nullifier,
        proof_values.x,
-        proof_values.epoch,
-        proof_values.rln_identifier,
+        proof_values.external_nullifier,
    ];

    // Check that the proof is valid
@@ -714,22 +695,71 @@ 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)
 }

-/// Get CIRCOM JSON inputs
+// auxiliary function for serialisation Fr to json using ark serilize
+fn ark_se<S, A: CanonicalSerialize>(a: &A, s: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    let mut bytes = vec![];
+    a.serialize_compressed(&mut bytes)
+        .map_err(serde::ser::Error::custom)?;
+    s.serialize_bytes(&bytes)
+}
+
+// auxiliary function for deserialisation Fr to json using ark serilize
+fn ark_de<'de, D, A: CanonicalDeserialize>(data: D) -> Result<A, D::Error>
+where
+    D: serde::de::Deserializer<'de>,
+{
+    let s: Vec<u8> = serde::de::Deserialize::deserialize(data)?;
+    let a = A::deserialize_compressed_unchecked(s.as_slice());
+    a.map_err(serde::de::Error::custom)
+}
+
+/// Converts a JSON value into [`RLNWitnessInput`] object.
 ///
-/// Returns a JSON object containing the inputs necessary to calculate
-/// the witness with CIRCOM on javascript
-pub fn get_json_inputs(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
+/// # Errors
+///
+/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
+pub fn rln_witness_from_json(input_json: serde_json::Value) -> Result<RLNWitnessInput> {
+    let rln_witness: RLNWitnessInput = serde_json::from_value(input_json).unwrap();
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
+
+    Ok(rln_witness)
+}
+
+/// Converts a [`RLNWitnessInput`] object to the corresponding JSON serialization.
+///
+/// # Errors
+///
+/// Returns an error if `message_id` is not within `user_message_limit`.
+pub fn rln_witness_to_json(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
+
+    let rln_witness_json = serde_json::to_value(rln_witness)?;
+    Ok(rln_witness_json)
+}
+
+/// Converts a [`RLNWitnessInput`] object to the corresponding JSON serialization.
+/// Before serialisation the data should be translated into big int for further calculation in the witness calculator.
+///
+/// # Errors
+///
+/// Returns an error if `message_id` is not within `user_message_limit`.
+pub fn rln_witness_to_bigint_json(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
+
    let mut path_elements = Vec::new();

    for v in rln_witness.path_elements.iter() {
@@ -743,13 +773,23 @@ pub fn get_json_inputs(rln_witness: &RLNWitnessInput) -> Result<serde_json::Valu
        .for_each(|v| identity_path_index.push(BigInt::from(*v).to_str_radix(10)));

    let inputs = serde_json::json!({
-        "identity_secret": to_bigint(&rln_witness.identity_secret)?.to_str_radix(10),
-        "path_elements": path_elements,
-        "identity_path_index": identity_path_index,
+        "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),
-        "epoch":  format!("0x{:064x}", to_bigint(&rln_witness.epoch)?),
-        "rln_identifier": to_bigint(&rln_witness.rln_identifier)?.to_str_radix(10),
+        "externalNullifier":  to_bigint(&rln_witness.external_nullifier)?.to_str_radix(10),
    });

    Ok(inputs)
 }
+
+pub fn message_id_range_check(message_id: &Fr, user_message_limit: &Fr) -> Result<()> {
+    if message_id > user_message_limit {
+        return Err(color_eyre::Report::msg(
+            "message_id is not within user_message_limit",
+        ));
+    }
+    Ok(())
+}
--- a/rln/src/public.rs
+++ b/rln/src/public.rs
--- a/rln/src/public_api_tests.rs
+++ b/rln/src/public_api_tests.rs
--- a/rln/src/utils.rs
+++ b/rln/src/utils.rs
@@ -1,22 +1,26 @@
 // This crate provides cross-module useful utilities (mainly type conversions) not necessarily specific to RLN

-use crate::circuit::Fr;
 use ark_ff::PrimeField;
 use color_eyre::{Report, Result};
 use num_bigint::{BigInt, BigUint};
 use num_traits::Num;
-use std::iter::Extend;
+use serde_json::json;
+use std::io::Cursor;

+use crate::circuit::Fr;
+
+#[inline(always)]
 pub fn to_bigint(el: &Fr) -> Result<BigInt> {
-    let res: BigUint = (*el).try_into()?;
-    Ok(res.into())
+    Ok(BigUint::from(*el).into())
 }

+#[inline(always)]
 pub fn fr_byte_size() -> usize {
    let mbs = <Fr as PrimeField>::MODULUS_BIT_SIZE;
    ((mbs + 64 - (mbs % 64)) / 8) as usize
 }

+#[inline(always)]
 pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
    if !(radix == 10 || radix == 16) {
        return Err(Report::msg("wrong radix"));
@@ -28,13 +32,14 @@ pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
    input_clean = input_clean.trim().to_string();

    if radix == 10 {
-        Ok(BigUint::from_str_radix(&input_clean, radix)?.try_into()?)
+        Ok(BigUint::from_str_radix(&input_clean, radix)?.into())
    } else {
        input_clean = input_clean.replace("0x", "");
-        Ok(BigUint::from_str_radix(&input_clean, radix)?.try_into()?)
+        Ok(BigUint::from_str_radix(&input_clean, radix)?.into())
    }
 }

+#[inline(always)]
 pub fn bytes_le_to_fr(input: &[u8]) -> (Fr, usize) {
    let el_size = fr_byte_size();
    (
@@ -43,77 +48,50 @@ pub fn bytes_le_to_fr(input: &[u8]) -> (Fr, usize) {
    )
 }

-pub fn bytes_be_to_fr(input: &[u8]) -> (Fr, usize) {
-    let el_size = fr_byte_size();
-    (
-        Fr::from(BigUint::from_bytes_be(&input[0..el_size])),
-        el_size,
-    )
-}
-
+#[inline(always)]
 pub fn fr_to_bytes_le(input: &Fr) -> Vec<u8> {
    let input_biguint: BigUint = (*input).into();
    let mut res = input_biguint.to_bytes_le();
    //BigUint conversion ignores most significant zero bytes. We restore them otherwise serialization will fail (length % 8 != 0)
-    while res.len() != fr_byte_size() {
-        res.push(0);
-    }
-    res
-}
-
-pub fn fr_to_bytes_be(input: &Fr) -> Vec<u8> {
-    let input_biguint: BigUint = (*input).into();
-    let mut res = input_biguint.to_bytes_be();
-    // BigUint conversion ignores most significant zero bytes. We restore them otherwise serialization might fail
-    // Fr elements are stored using 64 bits nimbs
-    while res.len() != fr_byte_size() {
-        res.insert(0, 0);
-    }
+    res.resize(fr_byte_size(), 0);
    res
 }

+#[inline(always)]
 pub fn vec_fr_to_bytes_le(input: &[Fr]) -> Result<Vec<u8>> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len())?.to_le_bytes().to_vec());
+    // Calculate capacity for Vec:
+    // - 8 bytes for normalized vector length (usize)
+    // - each Fr element requires fr_byte_size() bytes (typically 32 bytes)
+    let mut bytes = Vec::with_capacity(8 + input.len() * fr_byte_size());
+
+    // We store the vector length
+    bytes.extend_from_slice(&normalize_usize(input.len()));

    // We store each element
-    input.iter().for_each(|el| bytes.extend(fr_to_bytes_le(el)));
-
-    Ok(bytes)
-}
-
-pub fn vec_fr_to_bytes_be(input: &[Fr]) -> Result<Vec<u8>> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len())?.to_be_bytes().to_vec());
-
-    // We store each element
-    input.iter().for_each(|el| bytes.extend(fr_to_bytes_be(el)));
+    for el in input {
+        bytes.extend_from_slice(&fr_to_bytes_le(el));
+    }

    Ok(bytes)
 }

+#[inline(always)]
 pub fn vec_u8_to_bytes_le(input: &[u8]) -> Result<Vec<u8>> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len())?.to_le_bytes().to_vec());
+    // Calculate capacity for Vec:
+    // - 8 bytes for normalized vector length (usize)
+    // - variable length input data
+    let mut bytes = Vec::with_capacity(8 + input.len());

-    bytes.extend(input);
-
-    Ok(bytes)
-}
-
-pub fn vec_u8_to_bytes_be(input: Vec<u8>) -> Result<Vec<u8>> {
-    let mut bytes: Vec<u8> = Vec::new();
-    //We store the vector length
-    bytes.extend(u64::try_from(input.len())?.to_be_bytes().to_vec());
-
-    bytes.extend(input);
+    // We store the vector length
+    bytes.extend_from_slice(&normalize_usize(input.len()));
+
+    // We store the input
+    bytes.extend_from_slice(input);

    Ok(bytes)
 }

+#[inline(always)]
 pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize)> {
    let mut read: usize = 0;

@@ -126,19 +104,7 @@ pub fn bytes_le_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize)> {
    Ok((res, read))
 }

-pub fn bytes_be_to_vec_u8(input: &[u8]) -> Result<(Vec<u8>, usize)> {
-    let mut read: usize = 0;
-
-    let len = usize::try_from(u64::from_be_bytes(input[0..8].try_into()?))?;
-    read += 8;
-
-    let res = input[8..8 + len].to_vec();
-
-    read += res.len();
-
-    Ok((res, read))
-}
-
+#[inline(always)]
 pub fn bytes_le_to_vec_fr(input: &[u8]) -> Result<(Vec<Fr>, usize)> {
    let mut read: usize = 0;
    let mut res: Vec<Fr> = Vec::new();
@@ -156,159 +122,32 @@ 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
-}
-
-/* Old conversion utilities between different libraries data types
-
-// Conversion Utilities between poseidon-rs Field and arkworks Fr (in order to call directly poseidon-rs' poseidon_hash)
-
-use ff::{PrimeField as _, PrimeFieldRepr as _};
-use poseidon_rs::Fr as PosFr;
-
-pub fn fr_to_posfr(value: Fr) -> PosFr {
-    let mut bytes = [0_u8; 32];
-    let byte_vec = value.into_repr().to_bytes_be();
-    bytes.copy_from_slice(&byte_vec[..]);
-    let mut repr = <PosFr as ff::PrimeField>::Repr::default();
-    repr.read_be(&bytes[..])
-        .expect("read from correctly sized slice always succeeds");
-    PosFr::from_repr(repr).expect("value is always in range")
-}
-
-pub fn posfr_to_fr(value: PosFr) -> Fr {
-    let mut bytes = [0u8; 32];
-    value
-        .into_repr()
-        .write_be(&mut bytes[..])
-        .expect("write to correctly sized slice always succeeds");
-    Fr::from_be_bytes_mod_order(&bytes)
-}
-
-
-// Conversion Utilities between semaphore-rs Field and arkworks Fr
-
-use semaphore::Field;
-
-pub fn to_fr(el: &Field) -> Fr {
-    Fr::try_from(*el).unwrap()
-}
-
-pub fn to_field(el: &Fr) -> Field {
-    (*el).try_into().unwrap()
-}
-
-pub fn vec_to_fr(v: &[Field]) -> Vec<Fr> {
-    v.iter().map(|el| to_fr(el)).collect()
-}
-
-pub fn vec_to_field(v: &[Fr]) -> Vec<Field> {
-    v.iter().map(|el| to_field(el)).collect()
-}
-
-pub fn vec_fr_to_field(input: &[Fr]) -> Vec<Field> {
-    input.iter().map(|el| to_field(el)).collect()
-}
-
-pub fn vec_field_to_fr(input: &[Field]) -> Vec<Fr> {
-    input.iter().map(|el| to_fr(el)).collect()
-}
-
-pub fn str_to_field(input: String, radix: i32) -> Field {
-    assert!((radix == 10) || (radix == 16));
-
-    // We remove any quote present and we trim
-    let single_quote: char = '\"';
-    let input_clean = input.replace(single_quote, "");
-    let input_clean = input_clean.trim();
-
-    if radix == 10 {
-        Field::from_str(&format!(
-            "{:01$x}",
-            BigUint::from_str(input_clean).unwrap(),
-            64
-        ))
-        .unwrap()
+#[inline(always)]
+pub fn bytes_le_to_vec_usize(input: &[u8]) -> Result<Vec<usize>> {
+    let nof_elem = usize::try_from(u64::from_le_bytes(input[0..8].try_into()?))?;
+    if nof_elem == 0 {
+        Ok(vec![])
    } else {
-        let input_clean = input_clean.replace("0x", "");
-        Field::from_str(&format!("{:0>64}", &input_clean)).unwrap()
+        let elements: Vec<usize> = input[8..]
+            .chunks(8)
+            .map(|ch| usize::from_le_bytes(ch[0..8].try_into().unwrap()))
+            .collect();
+        Ok(elements)
    }
 }

-pub fn bytes_le_to_field(input: &[u8]) -> (Field, usize) {
-    let (fr_el, read) = bytes_le_to_fr(input);
-    (to_field(&fr_el), read)
+/// 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
 }

-pub fn bytes_be_to_field(input: &[u8]) -> (Field, usize) {
-    let (fr_el, read) = bytes_be_to_fr(input);
-    (to_field(&fr_el), read)
+#[inline(always)] // using for test
+pub fn generate_input_buffer() -> Cursor<String> {
+    Cursor::new(json!({}).to_string())
 }
-
-
-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)))
-}
-*/
--- a/rln/tests/ffi.rs
+++ b/rln/tests/ffi.rs
--- a/rln/tests/poseidon_tree.rs
+++ b/rln/tests/poseidon_tree.rs
@@ -4,48 +4,26 @@

 #[cfg(test)]
 mod test {
-    use rln::circuit::*;
-    use rln::hashers::PoseidonHash;
+    use rln::hashers::{poseidon_hash, PoseidonHash};
+    use rln::{circuit::*, poseidon_tree::PoseidonTree};
    use utils::{FullMerkleTree, OptimalMerkleTree, ZerokitMerkleProof, ZerokitMerkleTree};

    #[test]
-    /// A basic performance comparison between the two supported Merkle Tree implementations
-    fn test_zerokit_merkle_implementations_performances() {
-        use std::time::{Duration, Instant};
-
-        let tree_height = 20;
+    // The test is checked correctness for `FullMerkleTree` and `OptimalMerkleTree` with Poseidon hash
+    fn test_zerokit_merkle_implementations() {
        let sample_size = 100;
-
        let leaves: Vec<Fr> = (0..sample_size).map(|s| Fr::from(s)).collect();

-        let mut gen_time_full: u128 = 0;
-        let mut upd_time_full: u128 = 0;
-        let mut gen_time_opt: u128 = 0;
-        let mut upd_time_opt: u128 = 0;
-
-        for _ in 0..sample_size.try_into().unwrap() {
-            let now = Instant::now();
-            FullMerkleTree::<PoseidonHash>::default(tree_height).unwrap();
-            gen_time_full += now.elapsed().as_nanos();
-
-            let now = Instant::now();
-            OptimalMerkleTree::<PoseidonHash>::default(tree_height).unwrap();
-            gen_time_opt += now.elapsed().as_nanos();
-        }
-
-        let mut tree_full = FullMerkleTree::<PoseidonHash>::default(tree_height).unwrap();
-        let mut tree_opt = OptimalMerkleTree::<PoseidonHash>::default(tree_height).unwrap();
+        let mut tree_full = FullMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();
+        let mut tree_opt = OptimalMerkleTree::<PoseidonHash>::default(TEST_TREE_HEIGHT).unwrap();

        for i in 0..sample_size.try_into().unwrap() {
-            let now = Instant::now();
            tree_full.set(i, leaves[i]).unwrap();
-            upd_time_full += now.elapsed().as_nanos();
            let proof = tree_full.proof(i).expect("index should be set");
            assert_eq!(proof.leaf_index(), i);

-            let now = Instant::now();
            tree_opt.set(i, leaves[i]).unwrap();
-            upd_time_opt += now.elapsed().as_nanos();
+            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);
        }
@@ -55,26 +33,110 @@ mod test {
        let tree_opt_root = tree_opt.root();

        assert_eq!(tree_full_root, tree_opt_root);
+    }

-        println!(" Average tree generation time:");
-        println!(
-            "   - Full Merkle Tree:  {:?}",
-            Duration::from_nanos((gen_time_full / sample_size).try_into().unwrap())
-        );
-        println!(
-            "   - Optimal Merkle Tree: {:?}",
-            Duration::from_nanos((gen_time_opt / sample_size).try_into().unwrap())
+    #[test]
+    fn test_subtree_root() {
+        const DEPTH: usize = 3;
+        const LEAVES_LEN: usize = 8;
+
+        let mut tree = PoseidonTree::default(DEPTH).unwrap();
+        let leaves: Vec<Fr> = (0..LEAVES_LEN).map(|s| Fr::from(s as i32)).collect();
+        let _ = tree.set_range(0, leaves.into_iter());
+
+        for i in 0..LEAVES_LEN {
+            // check leaves
+            assert_eq!(
+                tree.get(i).unwrap(),
+                tree.get_subtree_root(DEPTH, i).unwrap()
+            );
+            // check root
+            assert_eq!(tree.root(), tree.get_subtree_root(0, i).unwrap());
+        }
+
+        // check intermediate nodes
+        for n in (1..=DEPTH).rev() {
+            for i in (0..(1 << n)).step_by(2) {
+                let idx_l = i * (1 << (DEPTH - n));
+                let idx_r = (i + 1) * (1 << (DEPTH - n));
+                let idx_sr = idx_l;
+
+                let prev_l = tree.get_subtree_root(n, idx_l).unwrap();
+                let prev_r = tree.get_subtree_root(n, idx_r).unwrap();
+                let subroot = tree.get_subtree_root(n - 1, idx_sr).unwrap();
+
+                assert_eq!(poseidon_hash(&[prev_l, prev_r]), subroot);
+            }
+        }
+    }
+
+    #[test]
+    fn test_get_empty_leaves_indices() {
+        let depth = 4;
+        let nof_leaves: usize = 1 << (depth - 1);
+
+        let mut tree = PoseidonTree::default(depth).unwrap();
+        let leaves: Vec<Fr> = (0..nof_leaves).map(|s| Fr::from(s as i32)).collect();
+
+        // check set_range
+        let _ = tree.set_range(0, leaves.clone().into_iter());
+        assert!(tree.get_empty_leaves_indices().is_empty());
+
+        let mut vec_idxs = Vec::new();
+        // check delete function
+        for i in 0..nof_leaves {
+            vec_idxs.push(i);
+            let _ = tree.delete(i);
+            assert_eq!(tree.get_empty_leaves_indices(), vec_idxs);
+        }
+        // check set function
+        for i in (0..nof_leaves).rev() {
+            vec_idxs.pop();
+            let _ = tree.set(i, leaves[i]);
+            assert_eq!(tree.get_empty_leaves_indices(), vec_idxs);
+        }
+
+        // check remove_indices_and_set_leaves inside override_range function
+        assert!(tree.get_empty_leaves_indices().is_empty());
+        let leaves_2: Vec<Fr> = (0..2).map(|s| Fr::from(s as i32)).collect();
+        tree.override_range(0, leaves_2.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .unwrap();
+        assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
+
+        // check remove_indices inside override_range function
+        tree.override_range(0, [].into_iter(), [0, 1].into_iter())
+            .unwrap();
+        assert_eq!(tree.get_empty_leaves_indices(), vec![0, 1, 2, 3]);
+
+        // check set_range inside override_range function
+        tree.override_range(0, leaves_2.clone().into_iter(), [].into_iter())
+            .unwrap();
+        assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
+
+        let leaves_4: Vec<Fr> = (0..4).map(|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().into_iter(), [0, 1, 2, 3].into_iter())
+            .unwrap();
+        assert!(tree.get_empty_leaves_indices().is_empty());
+
+        // check if indexes for deletion are before indexes for overwriting
+        tree.override_range(4, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .unwrap();
+        // The result will be like this, because in the set_range function in pmtree
+        // the next_index value is increased not by the number of elements to insert,
+        // but by the union of indices for deleting and inserting.
+        assert_eq!(
+            tree.get_empty_leaves_indices(),
+            vec![0, 1, 2, 3, 8, 9, 10, 11]
        );

-        println!(" Average update_next execution time:");
-        println!(
-            "   - Full Merkle Tree: {:?}",
-            Duration::from_nanos((upd_time_full / sample_size).try_into().unwrap())
-        );
-
-        println!(
-            "   - Optimal Merkle Tree: {:?}",
-            Duration::from_nanos((upd_time_opt / sample_size).try_into().unwrap())
-        );
+        // check if the indices for write and delete do not overlap completely
+        tree.override_range(2, leaves_4.clone().into_iter(), [0, 1, 2, 3].into_iter())
+            .unwrap();
+        // The result will be like this, because in the set_range function in pmtree
+        // the next_index value is increased not by the number of elements to insert,
+        // but by the union of indices for deleting and inserting.
+        // + we've already set to 6 and 7 in previous test
+        assert_eq!(tree.get_empty_leaves_indices(), vec![0, 1, 8, 9, 10, 11]);
    }
 }
--- a/rln/tests/protocol.rs
+++ b/rln/tests/protocol.rs
@@ -1,9 +1,8 @@
 #[cfg(test)]
 mod test {
-    use rln::circuit::{
-        circom_from_folder, vk_from_folder, zkey_from_folder, Fr, TEST_RESOURCES_FOLDER,
-        TEST_TREE_HEIGHT,
-    };
+    use ark_ff::BigInt;
+    use rln::circuit::{graph_from_folder, zkey_from_folder};
+    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
    use rln::hashers::{hash_to_field, poseidon_hash};
    use rln::poseidon_tree::PoseidonTree;
    use rln::protocol::*;
@@ -12,365 +11,134 @@ mod test {

    type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;

-    // Input generated with https://github.com/oskarth/zk-kit/commit/b6a872f7160c7c14e10a0ea40acab99cbb23c9a8
-    const WITNESS_JSON_15: &str = r#"
-            {
-              "identity_secret": "12825549237505733615964533204745049909430608936689388901883576945030025938736",
-              "path_elements": [
-                "18622655742232062119094611065896226799484910997537830749762961454045300666333",
-                "20590447254980891299813706518821659736846425329007960381537122689749540452732",
-                "7423237065226347324353380772367382631490014989348495481811164164159255474657",
-                "11286972368698509976183087595462810875513684078608517520839298933882497716792",
-                "3607627140608796879659380071776844901612302623152076817094415224584923813162",
-                "19712377064642672829441595136074946683621277828620209496774504837737984048981",
-                "20775607673010627194014556968476266066927294572720319469184847051418138353016",
-                "3396914609616007258851405644437304192397291162432396347162513310381425243293",
-                "21551820661461729022865262380882070649935529853313286572328683688269863701601",
-                "6573136701248752079028194407151022595060682063033565181951145966236778420039",
-                "12413880268183407374852357075976609371175688755676981206018884971008854919922",
-                "14271763308400718165336499097156975241954733520325982997864342600795471836726",
-                "20066985985293572387227381049700832219069292839614107140851619262827735677018",
-                "9394776414966240069580838672673694685292165040808226440647796406499139370960",
-                "11331146992410411304059858900317123658895005918277453009197229807340014528524"
-              ],
-              "identity_path_index": [
-                1,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0
-              ],
-              "x": "8143228284048792769012135629627737459844825626241842423967352803501040982",
-              "epoch": "0x0000005b612540fc986b42322f8cb91c2273afad58ed006fdba0c97b4b16b12f",
-              "rln_identifier": "11412926387081627876309792396682864042420635853496105400039841573530884328439"
-            }
-        "#;
-
-    // Input generated with protocol::random_rln_witness
-    const WITNESS_JSON_19: &str = r#"
-            {
-              "identity_secret": "922538810348594125658702672067738675294669207539999802857585668079702330450",
-              "path_elements": [
-                  "16059714054680148404543504061485737353203416489071538960876865983954285286166",
-                  "3041470753871943901334053763207316028823782848445723460227667780327106380356",
-                  "2557297527793326315072058421057853700096944625924483912548759909801348042183",
-                  "6677578602456189582427063963562590713054668181987223110955234085327917303436",
-                  "2250827150965576973906150764756422151438812678308727218463995574869267980301",
-                  "1895457427602709606993445561553433669787657053834360973759981803464906070980",
-                  "11033689991077061346803816826729204895841441316315304395980565540264104346466",
-                  "18588752216879570844240300406954267039026327526134910835334500497981810174976",
-                  "19346480964028499661277403659363466542857230928032088490855656809181891953123",
-                  "21460193770370072688835316363068413651465631481105148051902686770759127189327",
-                  "20906347653364838502964722817589315918082261023317339146393355650507243340078",
-                  "13466599592974387800162739317046838825289754472645703919149409009404541432954",
-                  "9617165663598957201253074168824246164494443748556931540348223968573884172285",
-                  "6936463137584425684797785981770877165377386163416057257854261010817156666898",
-                  "369902028235468424790098825415813437044876310542601948037281422841675126849",
-                  "13510969869821080499683463562609720931680005714401083864659516045615497273644",
-                  "2567921390740781421487331055530491683313154421589525170472201828596388395736",
-                  "14360870889466292805403568662660511177232987619663547772298178013674025998478",
-                  "4735344599616284973799984501493858013178071155960162022656706545116168334293"
-              ],
-              "identity_path_index": [
-                  1,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0
-              ],
-              "x": "6427050788896290028100534859169645070970780055911091444144195464808120686416",
-              "epoch": "0x2bd155d9f85c741044da6909d144f9cc5ce8e0d545a9ed4921b156e8b8569bab",
-              "rln_identifier": "2193983000213424579594329476781986065965849144986973472766961413131458022566"
-            }
-        "#;
-
-    const WITNESS_JSON_20: &str = r#"
-            {
-              "identity_secret": "13732353453861280511150022598793312186188599006979552959297495195757997428306",
-              "path_elements": [
-                  "20463525608687844300981085488128968694844212760055234622292326942405619575964",
-                  "8040856403709217901175408904825741112286158901303127670929462145501210871313",
-                  "3776499751255585163563840252112871568402966629435152937692711318702338789837",
-                  "19415813252626942110541463414404411443562242499365750694284604341271149125679",
-                  "19414720788761208006634240390286942738242262010168559813148115573784354129237",
-                  "17680594732844291740094158892269696200077963275550625226493856898849422516043",
-                  "16009199741350632715210088346611798597033333293348807000623441780059543674510",
-                  "18743496911007535170857676824393811326863602477260615792503039058813338644738",
-                  "1029572792321380246989475723806770724699749375691788486434716005338938722216",
-                  "21713138150151063186050010182615713685603650963220209951496401043119768920892",
-                  "6713732504049401389983008178456811894856018247924860823028704114266363984580",
-                  "2746686888799473963221285145390361693256731812094259845879519459924507786594",
-                  "18620748467731297359505500266677881218553438497271819903304075323783392031715",
-                  "2446201221122671119406471414204229600430018713181038717206670749886932158104",
-                  "12037171942017611311954851302868199608036334625783560875426350283156617524597",
-                  "21798743392351780927808323348278035105395367759688979232116905142049921734349",
-                  "17450230289417496971557215666910229260621413088991137405744457922069827319039",
-                  "20936854099128086256353520300046664152516566958630447858438908748907198510485",
-                  "13513344965831154386658059617477268600255664386844920822248038939666265737046",
-                  "15546319496880899251450021422131511560001766832580480193115646510655765306630"
-
-              ],
-              "identity_path_index": [
-                  0,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0
-              ],
-              "x": "18073935665561339809445069958310044423750771681863480888589546877024349720547",
-              "epoch": "0x147e4c23a43a1ddca78d94bcd28147f62ca74b3dc7e56bb0a314a954b9f0e567",
-              "rln_identifier": "2193983000213424579594329476781986065965849144986973472766961413131458022566"
-            }
-        "#;
-
    #[test]
    // We test Merkle tree generation, proofs and verification
    fn test_merkle_proof() {
-        let tree_height = TEST_TREE_HEIGHT;
        let leaf_index = 3;

        // generate identity
        let identity_secret_hash = hash_to_field(b"test-merkle-proof");
-        let id_commitment = poseidon_hash(&vec![identity_secret_hash]);
+        let id_commitment = poseidon_hash(&[identity_secret_hash]);
+        let rate_commitment = poseidon_hash(&[id_commitment, 100.into()]);

        // generate merkle tree
        let default_leaf = Fr::from(0);
        let mut tree = PoseidonTree::new(
-            tree_height,
+            TEST_TREE_HEIGHT,
            default_leaf,
            ConfigOf::<PoseidonTree>::default(),
        )
        .unwrap();
-        tree.set(leaf_index, id_commitment.into()).unwrap();
+        tree.set(leaf_index, rate_commitment.into()).unwrap();

        // We check correct computation of the root
        let root = tree.root();

-        if TEST_TREE_HEIGHT == 15 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x1984f2e01184aef5cb974640898a5f5c25556554e2b06d99d4841badb8b198cd",
-                    16
-                )
-                .unwrap()
-            );
-        } else if TEST_TREE_HEIGHT == 19 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x219ceb53f2b1b7a6cf74e80d50d44d68ecb4a53c6cc65b25593c8d56343fb1fe",
-                    16
-                )
-                .unwrap()
-            );
-        } else if TEST_TREE_HEIGHT == 20 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x21947ffd0bce0c385f876e7c97d6a42eec5b1fe935aab2f01c1f8a8cbcc356d2",
-                    16
-                )
-                .unwrap()
-            );
-        }
+        assert_eq!(
+            root,
+            BigInt([
+                4939322235247991215,
+                5110804094006647505,
+                4427606543677101242,
+                910933464535675827
+            ])
+            .into()
+        );

        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
        let path_elements = merkle_proof.get_path_elements();
        let identity_path_index = merkle_proof.get_path_index();

        // We check correct computation of the path and indexes
-        // These values refers to TEST_TREE_HEIGHT == 16
-        let mut expected_path_elements = vec![
-            str_to_fr(
-                "0x0000000000000000000000000000000000000000000000000000000000000000",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
-                16,
-            )
-            .unwrap(),
-        ];
+        let expected_path_elements: Vec<Fr> = [
+            "0x0000000000000000000000000000000000000000000000000000000000000000",
+            "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
+            "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
+            "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
+            "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
+            "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
+            "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
+            "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
+            "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
+            "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
+            "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
+            "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
+            "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
+            "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
+            "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
+            "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
+            "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
+            "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
+            "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
+            "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
+        ]
+        .map(|e| str_to_fr(e, 16).unwrap())
+        .to_vec();

-        let mut expected_identity_path_index: Vec<u8> =
-            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
-
-        // We add the remaining elements for the case TEST_TREE_HEIGHT = 20
-        if TEST_TREE_HEIGHT == 19 || TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![
-                str_to_fr(
-                    "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
-                    16,
-                )
-                .unwrap(),
-            ]);
-            expected_identity_path_index.append(&mut vec![0, 0, 0, 0]);
-        }
-
-        if TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![str_to_fr(
-                "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
-                16,
-            )
-            .unwrap()]);
-            expected_identity_path_index.append(&mut vec![0]);
-        }
+        let expected_identity_path_index: Vec<u8> =
+            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

        assert_eq!(path_elements, expected_path_elements);
        assert_eq!(identity_path_index, expected_identity_path_index);

        // We check correct verification of the proof
-        assert!(tree.verify(&id_commitment, &merkle_proof).unwrap());
+        assert!(tree.verify(&rate_commitment, &merkle_proof).unwrap());
+    }
+
+    fn get_test_witness() -> RLNWitnessInput {
+        let leaf_index = 3;
+        // Generate identity pair
+        let (identity_secret_hash, id_commitment) = keygen();
+        let user_message_limit = Fr::from(100);
+        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+
+        //// generate merkle tree
+        let default_leaf = Fr::from(0);
+        let mut tree = PoseidonTree::new(
+            TEST_TREE_HEIGHT,
+            default_leaf,
+            ConfigOf::<PoseidonTree>::default(),
+        )
+        .unwrap();
+        tree.set(leaf_index, rate_commitment.into()).unwrap();
+
+        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
+
+        let signal = b"hey hey";
+        let x = hash_to_field(signal);
+
+        // We set the remaining values to random ones
+        let epoch = hash_to_field(b"test-epoch");
+        let rln_identifier = hash_to_field(b"test-rln-identifier");
+        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+
+        rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x,
+            external_nullifier,
+            user_message_limit,
+            Fr::from(1),
+        )
+        .unwrap()
    }

    #[test]
    // We test a RLN proof generation and verification
    fn test_witness_from_json() {
        // We generate all relevant keys
-        let proving_key = zkey_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let verification_key = vk_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let builder = circom_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-
-        // We compute witness from the json input example
-        let mut witness_json: &str = "";
-
-        if TEST_TREE_HEIGHT == 15 {
-            witness_json = WITNESS_JSON_15;
-        } else if TEST_TREE_HEIGHT == 19 {
-            witness_json = WITNESS_JSON_19;
-        } else if TEST_TREE_HEIGHT == 20 {
-            witness_json = WITNESS_JSON_20;
-        }
-
-        let rln_witness = rln_witness_from_json(witness_json);
-
-        let rln_witness_unwrapped = rln_witness.unwrap();
+        let proving_key = zkey_from_folder();
+        let verification_key = &proving_key.0.vk;
+        let graph_data = graph_from_folder();
+        // We compute witness from the json input
+        let rln_witness = get_test_witness();
+        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
+        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
+        assert_eq!(rln_witness_deser, rln_witness);

        // Let's generate a zkSNARK proof
-        let proof = generate_proof(builder, &proving_key, &rln_witness_unwrapped).unwrap();
-
-        let proof_values = proof_values_from_witness(&rln_witness_unwrapped);
+        let proof = generate_proof(&proving_key, &rln_witness_deser, &graph_data).unwrap();
+        let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();

        // Let's verify the proof
        let verified = verify_proof(&verification_key, &proof, &proof_values);
@@ -381,47 +149,20 @@ mod test {
    #[test]
    // We test a RLN proof generation and verification
    fn test_end_to_end() {
-        let tree_height = TEST_TREE_HEIGHT;
-        let leaf_index = 3;
-
-        // Generate identity pair
-        let (identity_secret_hash, id_commitment) = keygen();
-
-        //// generate merkle tree
-        let default_leaf = Fr::from(0);
-        let mut tree = PoseidonTree::new(
-            tree_height,
-            default_leaf,
-            ConfigOf::<PoseidonTree>::default(),
-        )
-        .unwrap();
-        tree.set(leaf_index, id_commitment.into()).unwrap();
-
-        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
-
-        let signal = b"hey hey";
-        let x = hash_to_field(signal);
-
-        // We set the remaining values to random ones
-        let epoch = hash_to_field(b"test-epoch");
-        //let rln_identifier = hash_to_field(b"test-rln-identifier");
-
-        let rln_witness: RLNWitnessInput = rln_witness_from_values(
-            identity_secret_hash,
-            &merkle_proof,
-            x,
-            epoch, /*, rln_identifier*/
-        );
+        let rln_witness = get_test_witness();
+        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
+        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
+        assert_eq!(rln_witness_deser, rln_witness);

        // We generate all relevant keys
-        let proving_key = zkey_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let verification_key = vk_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let builder = circom_from_folder(TEST_RESOURCES_FOLDER).unwrap();
+        let proving_key = zkey_from_folder();
+        let verification_key = &proving_key.0.vk;
+        let graph_data = graph_from_folder();

        // Let's generate a zkSNARK proof
-        let proof = generate_proof(builder, &proving_key, &rln_witness).unwrap();
+        let proof = generate_proof(&proving_key, &rln_witness_deser, &graph_data).unwrap();

-        let proof_values = proof_values_from_witness(&rln_witness);
+        let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();

        // Let's verify the proof
        let success = verify_proof(&verification_key, &proof, &proof_values).unwrap();
@@ -431,25 +172,19 @@ mod test {

    #[test]
    fn test_witness_serialization() {
+        // We test witness JSON serialization
+        let rln_witness = get_test_witness();
+        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
+        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
+        assert_eq!(rln_witness_deser, rln_witness);
+
        // We test witness serialization
-        let mut witness_json: &str = "";
-
-        if TEST_TREE_HEIGHT == 15 {
-            witness_json = WITNESS_JSON_15;
-        } else if TEST_TREE_HEIGHT == 19 {
-            witness_json = WITNESS_JSON_19;
-        } else if TEST_TREE_HEIGHT == 20 {
-            witness_json = WITNESS_JSON_20;
-        }
-
-        let rln_witness = rln_witness_from_json(witness_json).unwrap();
-
        let ser = serialize_witness(&rln_witness).unwrap();
        let (deser, _) = deserialize_witness(&ser).unwrap();
        assert_eq!(rln_witness, deser);

        // We test Proof values serialization
-        let proof_values = proof_values_from_witness(&rln_witness);
+        let proof_values = proof_values_from_witness(&rln_witness).unwrap();
        let ser = serialize_proof_values(&proof_values);
        let (deser, _) = deserialize_proof_values(&ser);
        assert_eq!(proof_values, deser);
--- a/rln/tests/public.rs
+++ b/rln/tests/public.rs
@@ -1,66 +1,64 @@
 #[cfg(test)]
 mod test {
+    #[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_RESOURCES_FOLDER, 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 serde_json::json;
    use std::io::Cursor;

    #[test]
    // This test is similar to the one in lib, but uses only public API
+    #[cfg(not(feature = "stateless"))]
    fn test_merkle_proof() {
-        let tree_height = TEST_TREE_HEIGHT;
        let leaf_index = 3;
+        let user_message_limit = 1;

-        let input_buffer =
-            Cursor::new(json!({ "resources_folder": TEST_RESOURCES_FOLDER }).to_string());
-        let mut rln = RLN::new(tree_height, input_buffer).unwrap();
+        let mut rln = RLN::new(TEST_TREE_HEIGHT, generate_input_buffer()).unwrap();

        // generate identity
        let identity_secret_hash = hash_to_field(b"test-merkle-proof");
        let id_commitment = utils_poseidon_hash(&vec![identity_secret_hash]);
+        let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit.into()]);

-        // We pass id_commitment as Read buffer to RLN's set_leaf
-        let mut buffer = Cursor::new(fr_to_bytes_le(&id_commitment));
+        // check that leaves indices is empty
+        let mut buffer = Cursor::new(Vec::<u8>::new());
+        rln.get_empty_leaves_indices(&mut buffer).unwrap();
+        let idxs = bytes_le_to_vec_usize(&buffer.into_inner()).unwrap();
+        assert!(idxs.is_empty());
+
+        // We pass rate_commitment as Read buffer to RLN's set_leaf
+        let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
        rln.set_leaf(leaf_index, &mut buffer).unwrap();

+        // check that leaves before leaf_index is set to zero
+        let mut buffer = Cursor::new(Vec::<u8>::new());
+        rln.get_empty_leaves_indices(&mut buffer).unwrap();
+        let idxs = bytes_le_to_vec_usize(&buffer.into_inner()).unwrap();
+        assert_eq!(idxs, [0, 1, 2]);
+
        // We check correct computation of the root
        let mut buffer = Cursor::new(Vec::<u8>::new());
        rln.get_root(&mut buffer).unwrap();
        let (root, _) = bytes_le_to_fr(&buffer.into_inner());

-        if TEST_TREE_HEIGHT == 15 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x1984f2e01184aef5cb974640898a5f5c25556554e2b06d99d4841badb8b198cd",
-                    16
-                )
-                .unwrap()
-            );
-        } else if TEST_TREE_HEIGHT == 19 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x219ceb53f2b1b7a6cf74e80d50d44d68ecb4a53c6cc65b25593c8d56343fb1fe",
-                    16
-                )
-                .unwrap()
-            );
-        } else if TEST_TREE_HEIGHT == 20 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x21947ffd0bce0c385f876e7c97d6a42eec5b1fe935aab2f01c1f8a8cbcc356d2",
-                    16
-                )
-                .unwrap()
-            );
-        }
+        assert_eq!(
+            root,
+            Fr::from(BigInt([
+                17110646155607829651,
+                5040045984242729823,
+                6965416728592533086,
+                2328960363755461975
+            ]))
+        );

        // We check correct computation of merkle proof
        let mut buffer = Cursor::new(Vec::<u8>::new());
@@ -71,129 +69,67 @@ mod test {
        let (identity_path_index, _) = bytes_le_to_vec_u8(&buffer_inner[read..].to_vec()).unwrap();

        // We check correct computation of the path and indexes
-        let mut expected_path_elements = vec![
-            str_to_fr(
-                "0x0000000000000000000000000000000000000000000000000000000000000000",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
-                16,
-            )
-            .unwrap(),
-        ];
+        let expected_path_elements: Vec<Fr> = [
+            "0x0000000000000000000000000000000000000000000000000000000000000000",
+            "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
+            "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
+            "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
+            "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
+            "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
+            "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
+            "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
+            "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
+            "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
+            "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
+            "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
+            "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
+            "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
+            "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
+            "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
+            "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
+            "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
+            "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
+            "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
+        ]
+        .map(|e| str_to_fr(e, 16).unwrap())
+        .to_vec();

-        let mut expected_identity_path_index: Vec<u8> =
-            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
-
-        // We add the remaining elements for the case TEST_TREE_HEIGHT = 20
-        if TEST_TREE_HEIGHT == 19 || TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![
-                str_to_fr(
-                    "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
-                    16,
-                )
-                .unwrap(),
-            ]);
-            expected_identity_path_index.append(&mut vec![0, 0, 0, 0]);
-        }
-
-        if TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![str_to_fr(
-                "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
-                16,
-            )
-            .unwrap()]);
-            expected_identity_path_index.append(&mut vec![0]);
-        }
+        let expected_identity_path_index: Vec<u8> =
+            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];

        assert_eq!(path_elements, expected_path_elements);
        assert_eq!(identity_path_index, expected_identity_path_index);

+        // check subtree root computation for leaf 0 for all corresponding node until the root
+        let l_idx = 0;
+        for n in (1..=TEST_TREE_HEIGHT).rev() {
+            let idx_l = l_idx * (1 << (TEST_TREE_HEIGHT - n));
+            let idx_r = (l_idx + 1) * (1 << (TEST_TREE_HEIGHT - n));
+            let idx_sr = idx_l;
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n, idx_l, &mut buffer).unwrap();
+            let (prev_l, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n, idx_r, &mut buffer).unwrap();
+            let (prev_r, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n - 1, idx_sr, &mut buffer).unwrap();
+            let (subroot, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let res = utils_poseidon_hash(&[prev_l, prev_r]);
+            assert_eq!(res, subroot);
+        }
+
        // We double check that the proof computed from public API is correct
-        let root_from_proof =
-            compute_tree_root(&id_commitment, &path_elements, &identity_path_index, false);
+        let root_from_proof = compute_tree_root(
+            &identity_secret_hash,
+            &user_message_limit.into(),
+            &path_elements,
+            &identity_path_index,
+        );

        assert_eq!(root, root_from_proof);
    }
--- a/rln/vendor/rln
+++ b/rln/vendor/rln
--- a/semaphore/Cargo.toml
+++ b/semaphore/Cargo.toml
@@ -1,50 +0,0 @@
-[package]
-name = "semaphore-wrapper"
-version = "0.3.0"
-edition = "2021"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[features]
-default = []
-dylib = [ "wasmer/dylib", "wasmer-engine-dylib", "wasmer-compiler-cranelift" ]
-
-[dependencies]
-ark-bn254 = { version = "0.3.0" }
-ark-circom = { git = "https://github.com/gakonst/ark-circom", features=["circom-2"], rev = "35ce5a9" }
-ark-ec = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-ark-relations = { version = "0.3.0", default-features = false }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-color-eyre = "0.6.1"
-once_cell = "1.8"
-rand = "0.8.4"
-semaphore = { git = "https://github.com/worldcoin/semaphore-rs", rev = "ee658c2"}
-ethers-core = { version = "2.0.8", default-features = false }
-ruint = { version = "1.2.0", features = [ "serde", "num-bigint", "ark-ff" ] }
-serde = "1.0"
-thiserror = "1.0.0"
-wasmer = { version = "2.0" }
-
-[dev-dependencies]
-rand_chacha = "0.3.1"
-serde_json = "1.0.79"
-
-[build-dependencies]
-color-eyre = "0.6.1"
-wasmer = { version = "2.0" }
-wasmer-engine-dylib = { version = "2.2.1", optional = true }
-wasmer-compiler-cranelift = { version = "3.1.1", optional = true }
-
-[profile.release]
-codegen-units = 1
-lto = true
-panic = "abort"
-opt-level = 3
-
-# Compilation profile for any non-workspace member.
-# Dependencies are optimized, even in a dev build. This improves dev performance
-# while having neglible impact on incremental build times.
-[profile.dev.package."*"]
-opt-level = 3
--- a/semaphore/Makefile.toml
+++ b/semaphore/Makefile.toml
@@ -1,7 +0,0 @@
-[tasks.build]
-command = "cargo"
-args = ["build", "--release"]
-
-[tasks.test]
-command = "cargo"
-args = ["test", "--release"]
--- a/semaphore/README.md
+++ b/semaphore/README.md
@@ -1,18 +0,0 @@
-# Semaphore example package
-
-This is basically a wrapper around/copy of
-https://github.com/worldcoin/semaphore-rs to illustrate how e.g. RLN package
-can be structured like.
-
-Goal is also to provide a basic FFI around protocol.rs, which is currently not
-in scope for that project.
-
-See that project for more information.
-
-## Build and Test
-
-To build and test, run the following commands within the module folder
-```bash
-cargo make build
-cargo make test
-```
--- a/semaphore/build.rs
+++ b/semaphore/build.rs
@@ -1,111 +0,0 @@
-// Adapted from semaphore-rs/build.rs
-use color_eyre::eyre::{eyre, Result};
-use std::{
-    path::{Component, Path, PathBuf},
-    process::Command,
-};
-
-const ZKEY_FILE: &str = "./vendor/semaphore/build/snark/semaphore_final.zkey";
-const WASM_FILE: &str = "./vendor/semaphore/build/snark/semaphore.wasm";
-
-// See <https://internals.rust-lang.org/t/path-to-lexical-absolute/14940>
-fn absolute(path: &str) -> Result<PathBuf> {
-    let path = Path::new(path);
-    let mut absolute = if path.is_absolute() {
-        PathBuf::new()
-    } else {
-        std::env::current_dir()?
-    };
-    for component in path.components() {
-        match component {
-            Component::CurDir => {}
-            Component::ParentDir => {
-                absolute.pop();
-            }
-            component => absolute.push(component.as_os_str()),
-        }
-    }
-    Ok(absolute)
-}
-
-fn build_circuit() -> Result<()> {
-    println!("cargo:rerun-if-changed=./vendor/semaphore");
-    let run = |cmd: &[&str]| -> Result<()> {
-        // TODO: Use ExitCode::exit_ok() when stable.
-        Command::new(cmd[0])
-            .args(cmd[1..].iter())
-            .current_dir("./vendor/semaphore")
-            .status()?
-            .success()
-            .then_some(())
-            .ok_or(eyre!("procees returned failure"))?;
-        Ok(())
-    };
-
-    // Compute absolute paths
-    let zkey_file = absolute(ZKEY_FILE)?;
-    let wasm_file = absolute(WASM_FILE)?;
-
-    // Build circuits if not exists
-    // TODO: This does not rebuild if the semaphore submodule is changed.
-    // NOTE: This requires npm / nodejs to be installed.
-    if !(zkey_file.exists() && wasm_file.exists()) {
-        run(&["npm", "install"])?;
-        run(&["npm", "exec", "ts-node", "./scripts/compile-circuits.ts"])?;
-    }
-    assert!(zkey_file.exists());
-    assert!(wasm_file.exists());
-
-    // Export generated paths
-    println!("cargo:rustc-env=BUILD_RS_ZKEY_FILE={}", zkey_file.display());
-    println!("cargo:rustc-env=BUILD_RS_WASM_FILE={}", wasm_file.display());
-
-    Ok(())
-}
-
-#[cfg(feature = "dylib")]
-fn build_dylib() -> Result<()> {
-    use enumset::enum_set;
-    use std::{env, str::FromStr};
-    use wasmer::{Module, Store, Target, Triple};
-    use wasmer_compiler_cranelift::Cranelift;
-    use wasmer_engine_dylib::Dylib;
-
-    let wasm_file = absolute(WASM_FILE)?;
-    assert!(wasm_file.exists());
-
-    let out_dir = env::var("OUT_DIR")?;
-    let out_dir = Path::new(&out_dir).to_path_buf();
-    let dylib_file = out_dir.join("semaphore.dylib");
-    println!(
-        "cargo:rustc-env=CIRCUIT_WASM_DYLIB={}",
-        dylib_file.display()
-    );
-
-    if dylib_file.exists() {
-        return Ok(());
-    }
-
-    // Create a WASM engine for the target that can compile
-    let triple = Triple::from_str(&env::var("TARGET")?).map_err(|e| eyre!(e))?;
-    let cpu_features = enum_set!();
-    let target = Target::new(triple, cpu_features);
-    let compiler_config = Cranelift::default();
-    let engine = Dylib::new(compiler_config).target(target).engine();
-
-    // Compile the WASM module
-    let store = Store::new(&engine);
-    let module = Module::from_file(&store, &wasm_file)?;
-    module.serialize_to_file(&dylib_file)?;
-    assert!(dylib_file.exists());
-    println!("cargo:warning=Circuit dylib is in {}", dylib_file.display());
-
-    Ok(())
-}
-
-fn main() -> Result<()> {
-    build_circuit()?;
-    #[cfg(feature = "dylib")]
-    build_dylib()?;
-    Ok(())
-}
--- a/semaphore/src/circuit.rs
+++ b/semaphore/src/circuit.rs
@@ -1,79 +0,0 @@
-// Adapted from semaphore-rs/src/circuit.rs
-use ark_bn254::{Bn254, Fr};
-use ark_circom::{read_zkey, WitnessCalculator};
-use ark_groth16::ProvingKey;
-use ark_relations::r1cs::ConstraintMatrices;
-use core::include_bytes;
-use once_cell::sync::{Lazy, OnceCell};
-use std::{io::Cursor, sync::Mutex};
-use wasmer::{Module, Store};
-
-#[cfg(feature = "dylib")]
-use std::{env, path::Path};
-#[cfg(feature = "dylib")]
-use wasmer::Dylib;
-
-const ZKEY_BYTES: &[u8] = include_bytes!(env!("BUILD_RS_ZKEY_FILE"));
-
-#[cfg(not(feature = "dylib"))]
-const WASM: &[u8] = include_bytes!(env!("BUILD_RS_WASM_FILE"));
-
-static ZKEY: Lazy<(ProvingKey<Bn254>, ConstraintMatrices<Fr>)> = Lazy::new(|| {
-    let mut reader = Cursor::new(ZKEY_BYTES);
-    read_zkey(&mut reader).expect("zkey should be valid")
-});
-
-static WITNESS_CALCULATOR: OnceCell<Mutex<WitnessCalculator>> = OnceCell::new();
-
-/// Initialize the library.
-#[cfg(feature = "dylib")]
-pub fn initialize(dylib_path: &Path) {
-    WITNESS_CALCULATOR
-        .set(from_dylib(dylib_path))
-        .expect("Failed to initialize witness calculator");
-
-    // Force init of ZKEY
-    Lazy::force(&ZKEY);
-}
-
-#[cfg(feature = "dylib")]
-fn from_dylib(path: &Path) -> Mutex<WitnessCalculator> {
-    let store = Store::new(&Dylib::headless().engine());
-    // The module must be exported using [`Module::serialize`].
-    let module = unsafe {
-        Module::deserialize_from_file(&store, path).expect("Failed to load wasm dylib module")
-    };
-    let result =
-        WitnessCalculator::from_module(module).expect("Failed to create witness calculator");
-    Mutex::new(result)
-}
-
-#[must_use]
-pub fn zkey() -> &'static (ProvingKey<Bn254>, ConstraintMatrices<Fr>) {
-    &ZKEY
-}
-
-#[cfg(feature = "dylib")]
-#[must_use]
-pub fn witness_calculator() -> &'static Mutex<WitnessCalculator> {
-    WITNESS_CALCULATOR.get_or_init(|| {
-        let path = env::var("CIRCUIT_WASM_DYLIB").expect(
-            "Semaphore-rs is not initialized. The library needs to be initialized before use when \
-             build with the `cdylib` feature. You can initialize by calling `initialize` or \
-             seting the `CIRCUIT_WASM_DYLIB` environment variable.",
-        );
-        from_dylib(Path::new(&path))
-    })
-}
-
-#[cfg(not(feature = "dylib"))]
-#[must_use]
-pub fn witness_calculator() -> &'static Mutex<WitnessCalculator> {
-    WITNESS_CALCULATOR.get_or_init(|| {
-        let store = Store::default();
-        let module = Module::from_binary(&store, WASM).expect("wasm should be valid");
-        let result =
-            WitnessCalculator::from_module(module).expect("Failed to create witness calculator");
-        Mutex::new(result)
-    })
-}
--- a/semaphore/src/lib.rs
+++ b/semaphore/src/lib.rs
@@ -1,7 +0,0 @@
-#![allow(clippy::multiple_crate_versions)]
-
-pub mod circuit;
-pub mod protocol;
-
-#[cfg(feature = "dylib")]
-pub use circuit::initialize;
--- a/semaphore/src/protocol.rs
+++ b/semaphore/src/protocol.rs
@@ -1,215 +0,0 @@
-// Adapted from semaphore-rs/src/protocol.rs
-// For illustration purposes only as an example protocol
-
-// Private module
-use crate::circuit::{witness_calculator, zkey};
-
-use ark_bn254::{Bn254, Parameters};
-use ark_circom::CircomReduction;
-use ark_ec::bn::Bn;
-use ark_groth16::{
-    create_proof_with_reduction_and_matrices, prepare_verifying_key, Proof as ArkProof,
-};
-use ark_relations::r1cs::SynthesisError;
-use ark_std::UniformRand;
-use color_eyre::{Report, Result};
-use ethers_core::types::U256;
-use rand::{thread_rng, Rng};
-use semaphore::{
-    identity::Identity,
-    merkle_tree::{self, Branch},
-    poseidon,
-    poseidon_tree::PoseidonHash,
-    Field,
-};
-use serde::{Deserialize, Serialize};
-use std::time::Instant;
-use thiserror::Error;
-
-// Matches the private G1Tup type in ark-circom.
-pub type G1 = (U256, U256);
-
-// Matches the private G2Tup type in ark-circom.
-pub type G2 = ([U256; 2], [U256; 2]);
-
-/// Wrap a proof object so we have serde support
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
-pub struct Proof(G1, G2, G1);
-
-impl From<ArkProof<Bn<Parameters>>> for Proof {
-    fn from(proof: ArkProof<Bn<Parameters>>) -> Self {
-        let proof = ark_circom::ethereum::Proof::from(proof);
-        let (a, b, c) = proof.as_tuple();
-        Self(a, b, c)
-    }
-}
-
-impl From<Proof> for ArkProof<Bn<Parameters>> {
-    fn from(proof: Proof) -> Self {
-        let eth_proof = ark_circom::ethereum::Proof {
-            a: ark_circom::ethereum::G1 {
-                x: proof.0 .0,
-                y: proof.0 .1,
-            },
-            #[rustfmt::skip] // Rustfmt inserts some confusing spaces
-            b: ark_circom::ethereum::G2 {
-                // The order of coefficients is flipped.
-                x: [proof.1.0[1], proof.1.0[0]],
-                y: [proof.1.1[1], proof.1.1[0]],
-            },
-            c: ark_circom::ethereum::G1 {
-                x: proof.2 .0,
-                y: proof.2 .1,
-            },
-        };
-        eth_proof.into()
-    }
-}
-
-/// Helper to merkle proof into a bigint vector
-/// TODO: we should create a From trait for this
-fn merkle_proof_to_vec(proof: &merkle_tree::Proof<PoseidonHash>) -> Vec<Field> {
-    proof
-        .0
-        .iter()
-        .map(|x| match x {
-            Branch::Left(value) | Branch::Right(value) => *value,
-        })
-        .collect()
-}
-
-/// Generates the nullifier hash
-#[must_use]
-pub fn generate_nullifier_hash(identity: &Identity, external_nullifier: Field) -> Field {
-    poseidon::hash2(external_nullifier, identity.nullifier)
-}
-
-#[derive(Error, Debug)]
-pub enum ProofError {
-    #[error("Error reading circuit key: {0}")]
-    CircuitKeyError(#[from] std::io::Error),
-    #[error("Error producing witness: {0}")]
-    WitnessError(Report),
-    #[error("Error producing proof: {0}")]
-    SynthesisError(#[from] SynthesisError),
-    #[error("Error converting public input: {0}")]
-    ToFieldError(#[from] ruint::ToFieldError),
-}
-
-/// Generates a semaphore proof
-///
-/// # Errors
-///
-/// Returns a [`ProofError`] if proving fails.
-pub fn generate_proof(
-    identity: &Identity,
-    merkle_proof: &merkle_tree::Proof<PoseidonHash>,
-    external_nullifier_hash: Field,
-    signal_hash: Field,
-) -> Result<Proof, ProofError> {
-    generate_proof_rng(
-        identity,
-        merkle_proof,
-        external_nullifier_hash,
-        signal_hash,
-        &mut thread_rng(),
-    )
-}
-
-/// Generates a semaphore proof from entropy
-///
-/// # Errors
-///
-/// Returns a [`ProofError`] if proving fails.
-pub fn generate_proof_rng(
-    identity: &Identity,
-    merkle_proof: &merkle_tree::Proof<PoseidonHash>,
-    external_nullifier_hash: Field,
-    signal_hash: Field,
-    rng: &mut impl Rng,
-) -> Result<Proof, ProofError> {
-    generate_proof_rs(
-        identity,
-        merkle_proof,
-        external_nullifier_hash,
-        signal_hash,
-        ark_bn254::Fr::rand(rng),
-        ark_bn254::Fr::rand(rng),
-    )
-}
-
-fn generate_proof_rs(
-    identity: &Identity,
-    merkle_proof: &merkle_tree::Proof<PoseidonHash>,
-    external_nullifier_hash: Field,
-    signal_hash: Field,
-    r: ark_bn254::Fr,
-    s: ark_bn254::Fr,
-) -> Result<Proof, ProofError> {
-    let inputs = [
-        ("identityNullifier", vec![identity.nullifier]),
-        ("identityTrapdoor", vec![identity.trapdoor]),
-        ("treePathIndices", merkle_proof.path_index()),
-        ("treeSiblings", merkle_proof_to_vec(merkle_proof)),
-        ("externalNullifier", vec![external_nullifier_hash]),
-        ("signalHash", vec![signal_hash]),
-    ];
-    let inputs = inputs.into_iter().map(|(name, values)| {
-        (
-            name.to_string(),
-            values.iter().copied().map(Into::into).collect::<Vec<_>>(),
-        )
-    });
-
-    let now = Instant::now();
-
-    let full_assignment = witness_calculator()
-        .lock()
-        .expect("witness_calculator mutex should not get poisoned")
-        .calculate_witness_element::<Bn254, _>(inputs, false)
-        .map_err(ProofError::WitnessError)?;
-
-    println!("witness generation took: {:.2?}", now.elapsed());
-
-    let now = Instant::now();
-    let zkey = zkey();
-    let ark_proof = create_proof_with_reduction_and_matrices::<_, CircomReduction>(
-        &zkey.0,
-        r,
-        s,
-        &zkey.1,
-        zkey.1.num_instance_variables,
-        zkey.1.num_constraints,
-        full_assignment.as_slice(),
-    )?;
-    let proof = ark_proof.into();
-    println!("proof generation took: {:.2?}", now.elapsed());
-
-    Ok(proof)
-}
-
-/// Verifies a given semaphore proof
-///
-/// # Errors
-///
-/// Returns a [`ProofError`] if verifying fails. Verification failure does not
-/// necessarily mean the proof is incorrect.
-pub fn verify_proof(
-    root: Field,
-    nullifier_hash: Field,
-    signal_hash: Field,
-    external_nullifier_hash: Field,
-    proof: &Proof,
-) -> Result<bool, ProofError> {
-    let zkey = zkey();
-    let pvk = prepare_verifying_key(&zkey.0.vk);
-
-    let public_inputs = [root, nullifier_hash, signal_hash, external_nullifier_hash]
-        .iter()
-        .map(ark_bn254::Fr::try_from)
-        .collect::<Result<Vec<_>, _>>()?;
-
-    let ark_proof = (*proof).into();
-    let result = ark_groth16::verify_proof(&pvk, &ark_proof, &public_inputs[..])?;
-    Ok(result)
-}
--- a/semaphore/tests/protocol.rs
+++ b/semaphore/tests/protocol.rs
@@ -1,115 +0,0 @@
-#[cfg(test)]
-mod tests {
-    use ark_bn254::Parameters;
-    use ark_ec::bn::Bn;
-    use ark_groth16::Proof as ArkProof;
-    use rand::{Rng, SeedableRng as _};
-    use rand_chacha::ChaChaRng;
-    use semaphore::{hash_to_field, identity::Identity, poseidon_tree::PoseidonTree, Field};
-    use semaphore_wrapper::protocol::{
-        generate_nullifier_hash, generate_proof, generate_proof_rng, verify_proof, Proof,
-    };
-    use serde_json::json;
-
-    #[test]
-    fn test_semaphore() {
-        // generate identity
-        let id = Identity::from_seed(b"secret");
-
-        // generate merkle tree
-        let leaf = Field::from(0);
-        let mut tree = PoseidonTree::new(21, leaf);
-        tree.set(0, id.commitment());
-
-        let merkle_proof = tree.proof(0).expect("proof should exist");
-        let root = tree.root().into();
-
-        // change signal and external_nullifier here
-        let signal_hash = hash_to_field(b"xxx");
-        let external_nullifier_hash = hash_to_field(b"appId");
-
-        let nullifier_hash = generate_nullifier_hash(&id, external_nullifier_hash);
-
-        let proof =
-            generate_proof(&id, &merkle_proof, external_nullifier_hash, signal_hash).unwrap();
-
-        let success = verify_proof(
-            root,
-            nullifier_hash,
-            signal_hash,
-            external_nullifier_hash,
-            &proof,
-        )
-        .unwrap();
-
-        assert!(success);
-    }
-
-    fn arb_proof(seed: u64) -> Proof {
-        // Deterministic randomness for testing
-        let mut rng = ChaChaRng::seed_from_u64(seed);
-
-        // generate identity
-        let seed: [u8; 16] = rng.gen();
-        let id = Identity::from_seed(&seed);
-
-        // generate merkle tree
-        let leaf = Field::from(0);
-        let mut tree = PoseidonTree::new(21, leaf);
-        tree.set(0, id.commitment());
-
-        let merkle_proof = tree.proof(0).expect("proof should exist");
-
-        let external_nullifier: [u8; 16] = rng.gen();
-        let external_nullifier_hash = hash_to_field(&external_nullifier);
-
-        let signal: [u8; 16] = rng.gen();
-        let signal_hash = hash_to_field(&signal);
-
-        generate_proof_rng(
-            &id,
-            &merkle_proof,
-            external_nullifier_hash,
-            signal_hash,
-            &mut rng,
-        )
-        .unwrap()
-    }
-
-    #[test]
-    fn test_proof_cast_roundtrip() {
-        let proof = arb_proof(123);
-        let ark_proof: ArkProof<Bn<Parameters>> = proof.into();
-        let result: Proof = ark_proof.into();
-        assert_eq!(proof, result);
-    }
-
-    #[test]
-    fn test_proof_serialize() {
-        let proof = arb_proof(456);
-        let json = serde_json::to_value(&proof).unwrap();
-        assert_eq!(
-            json,
-            json!([
-                [
-                    "0x249ae469686987ee9368da60dd177a8c42891c02f5760e955e590c79d55cfab2",
-                    "0xf22e25870f49388459d388afb24dcf6ec11bb2d4def1e2ec26d6e42f373aad8"
-                ],
-                [
-                    [
-                        "0x17bd25dbd7436c30ea5b8a3a47aadf11ed646c4b25cc14a84ff8cbe0252ff1f8",
-                        "0x1c140668c56688367416534d57b4a14e5a825efdd5e121a6a2099f6dc4cd277b"
-                    ],
-                    [
-                        "0x26a8524759d969ea0682a092cf7a551697d81962d6c998f543f81e52d83e05e1",
-                        "0x273eb3f796fd1807b9df9c6d769d983e3dabdc61677b75d48bb7691303b2c8dd"
-                    ]
-                ],
-                [
-                    "0x62715c53a0eb4c46dbb5f73f1fd7449b9c63d37c1ece65debc39b472065a90f",
-                    "0x114f7becc66f1cd7a8b01c89db8233622372fc0b6fc037c4313bca41e2377fd9"
-                ]
-            ])
-        );
-    }
-}
--- a/semaphore/vendor/semaphore
+++ b/semaphore/vendor/semaphore
--- a/utils/Cargo.toml
+++ b/utils/Cargo.toml
@@ -1,33 +1,45 @@
 [package]
 name = "zerokit_utils"
-version = "0.3.0"
+version = "0.5.2"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Various utilities for Zerokit"
+documentation = "https://github.com/vacp2p/zerokit"
+homepage = "https://vac.dev"
+repository = "https://github.com/vacp2p/zerokit"

 [lib]
 bench = false

 [dependencies]
-ark-ff = { version = "=0.4.1", default-features = false, features = ["asm"] }
-num-bigint = { version = "=0.4.3", default-features = false, features = ["rand"] }
-color-eyre = "=0.6.2"
-pmtree = { package = "vacp2p_pmtree", version = "=1.0.0", optional = true}
-sled = "=0.34.7"
-serde = "=1.0.163"
+ark-ff = { version = "0.5.0", default-features = false, features = [
+    "parallel",
+] }
+num-bigint = { version = "0.4.6", default-features = false, features = [
+    "rand",
+] }
+color-eyre = "0.6.3"
+pmtree = { package = "vacp2p_pmtree", version = "2.0.2", optional = true }
+sled = "0.34.7"
+serde = "1.0"
+lazy_static = "1.5.0"
+hex = "0.4"

 [dev-dependencies]
-ark-bn254 = "=0.4.0"
-num-traits = "=0.2.15"
-hex-literal = "=0.3.4"
-tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
-criterion = { version = "=0.4.0", features = ["html_reports"] }
+ark-bn254 = { version = "0.5.0", features = ["std"] }
+num-traits = "0.2.19"
+hex-literal = "1.0.0"
+tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+criterion = { version = "0.4.0", 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
--- a/utils/Makefile.toml
+++ b/utils/Makefile.toml
@@ -8,4 +8,4 @@ args = ["test", "--release"]

 [tasks.bench]
 command = "cargo"
-args = ["bench"]
+args = ["bench"]
--- a/utils/README.md
+++ b/utils/README.md
@@ -1,15 +1,111 @@
-# Utils crate
+# Zerokit Utils Crate

-## Building
+[![Crates.io](https://img.shields.io/crates/v/zerokit_utils.svg)](https://crates.io/crates/zerokit_utils)

-1. `cargo build`
+Cryptographic primitives for zero-knowledge applications, featuring efficient Merkle tree implementations and a Poseidon hash function.

-## Testing
+## Overview

-1. `cargo test`
+This crate provides core cryptographic components optimized for zero-knowledge proof systems:

-## Benchmarking
+1. Multiple Merkle tree implementations with different space/time tradeoffs
+2. A Poseidon hash implementation

-1. `cargo bench`
+## Merkle Tree Implementations

-To view the results of the benchmark, open the `target/criterion/report/index.html` file generated after the bench
+The crate supports two interchangeable Merkle tree implementations:
+
+- **FullMerkleTree**
+  - Stores each tree node in memory
+- **OptimalMerkleTree**
+  - Only stores nodes used to prove accumulation of set leaves
+
+### Implementation notes
+
+Glossary:
+
+* depth: level of leaves if we count from levels from 0
+* number of levels: depth + 1
+* capacity (== number of leaves) -- 1 << depth
+* total number of nodes: 1 << (depth + 1)) - 1
+
+So for instance:
+* depth: 3
+* number of levels: 4
+* capacity (number of leaves): 8
+* total number of nodes: 15
+
+```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
+```
+
+
+## Poseidon Hash Implementation
+
+This crate provides an implementation to compute the Poseidon hash round constants and MDS matrices:
+
+- **Customizable parameters**: Supports different security levels and input sizes
+- **Arkworks-friendly**: Adapted to work over arkworks field traits and custom data structures
+
+### Security Note
+
+The MDS matrices are generated iteratively using the Grain LFSR until certain criteria are met.
+According to the paper, such matrices must respect specific conditions which are checked by 3 different algorithms in the reference implementation.
+
+These validation algorithms are not currently implemented in this crate.
+For the hardcoded parameters, the first random matrix generated satisfies these conditions.
+If using different parameters, you should check against the reference implementation how many matrices are generated before outputting the correct one,
+and pass this number to the `skip_matrices` parameter of the `find_poseidon_ark_and_mds` function.
+
+## Installation
+
+Add Zerokit Utils to your Rust project:
+
+```toml
+[dependencies]
+zerokit-utils = "0.5.1"
+```
+
+## Performance Considerations
+
+- **FullMerkleTree**: Use when memory is abundant and operation speed is critical
+- **OptimalMerkleTree**: Use when memory efficiency is more important than raw speed
+- **Poseidon**: Offers a good balance between security and performance for ZK applications
+
+## Building and Testing
+
+```bash
+# Build the crate
+cargo 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)
--- a/utils/benches/merkle_tree_benchmark.rs
+++ b/utils/benches/merkle_tree_benchmark.rs
@@ -1,5 +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 tiny_keccak::{Hasher as _, Keccak};
 use zerokit_utils::{
    FullMerkleConfig, FullMerkleTree, Hasher, OptimalMerkleConfig, OptimalMerkleTree,
@@ -9,38 +11,59 @@ use zerokit_utils::{
 #[derive(Clone, Copy, Eq, PartialEq)]
 struct Keccak256;

+#[derive(Clone, Copy, Eq, PartialEq, Debug, Default)]
+struct TestFr([u8; 32]);
+
 impl Hasher for Keccak256 {
-    type Fr = [u8; 32];
+    type Fr = TestFr;

    fn default_leaf() -> Self::Fr {
-        [0; 32]
+        TestFr([0; 32])
    }

    fn hash(inputs: &[Self::Fr]) -> Self::Fr {
        let mut output = [0; 32];
        let mut hasher = Keccak::v256();
        for element in inputs {
-            hasher.update(element);
+            hasher.update(element.0.as_slice());
        }
        hasher.finalize(&mut output);
-        output
+        TestFr(output)
    }
 }

-pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
-    let mut tree =
-        OptimalMerkleTree::<Keccak256>::new(2, [0; 32], OptimalMerkleConfig::default()).unwrap();
+impl Display for TestFr {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", String::from_utf8_lossy(self.0.as_slice()))
+    }
+}

-    let leaves = [
+impl FromStr for TestFr {
+    type Err = std::string::FromUtf8Error;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        Ok(TestFr(s.as_bytes().try_into().unwrap()))
+    }
+}
+
+lazy_static! {
+    static ref LEAVES: [TestFr; 4] = [
        hex!("0000000000000000000000000000000000000000000000000000000000000001"),
        hex!("0000000000000000000000000000000000000000000000000000000000000002"),
        hex!("0000000000000000000000000000000000000000000000000000000000000003"),
        hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-    ];
+    ]
+    .map(TestFr);
+}
+
+pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
+    let mut tree =
+        OptimalMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), OptimalMerkleConfig::default())
+            .unwrap();

    c.bench_function("OptimalMerkleTree::set", |b| {
        b.iter(|| {
-            tree.set(0, leaves[0]).unwrap();
+            tree.set(0, LEAVES[0]).unwrap();
        })
    });

@@ -52,7 +75,8 @@ pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {

    c.bench_function("OptimalMerkleTree::override_range", |b| {
        b.iter(|| {
-            tree.override_range(0, leaves, [0, 1, 2, 3]).unwrap();
+            tree.override_range(0, LEAVES.into_iter(), [0, 1, 2, 3].into_iter())
+                .unwrap();
        })
    });

@@ -67,22 +91,28 @@ pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
            tree.get(0).unwrap();
        })
    });
+
+    // check intermediate node getter which required additional computation of sub root index
+    c.bench_function("OptimalMerkleTree::get_subtree_root", |b| {
+        b.iter(|| {
+            tree.get_subtree_root(1, 0).unwrap();
+        })
+    });
+
+    c.bench_function("OptimalMerkleTree::get_empty_leaves_indices", |b| {
+        b.iter(|| {
+            tree.get_empty_leaves_indices();
+        })
+    });
 }

 pub fn full_merkle_tree_benchmark(c: &mut Criterion) {
    let mut tree =
-        FullMerkleTree::<Keccak256>::new(2, [0; 32], FullMerkleConfig::default()).unwrap();
-
-    let leaves = [
-        hex!("0000000000000000000000000000000000000000000000000000000000000001"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000002"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000003"),
-        hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-    ];
+        FullMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), FullMerkleConfig::default()).unwrap();

    c.bench_function("FullMerkleTree::set", |b| {
        b.iter(|| {
-            tree.set(0, leaves[0]).unwrap();
+            tree.set(0, LEAVES[0]).unwrap();
        })
    });

@@ -94,7 +124,8 @@ pub fn full_merkle_tree_benchmark(c: &mut Criterion) {

    c.bench_function("FullMerkleTree::override_range", |b| {
        b.iter(|| {
-            tree.override_range(0, leaves, [0, 1, 2, 3]).unwrap();
+            tree.override_range(0, LEAVES.into_iter(), [0, 1, 2, 3].into_iter())
+                .unwrap();
        })
    });

@@ -109,6 +140,19 @@ pub fn full_merkle_tree_benchmark(c: &mut Criterion) {
            tree.get(0).unwrap();
        })
    });
+
+    // check intermediate node getter which required additional computation of sub root index
+    c.bench_function("FullMerkleTree::get_subtree_root", |b| {
+        b.iter(|| {
+            tree.get_subtree_root(1, 0).unwrap();
+        })
+    });
+
+    c.bench_function("FullMerkleTree::get_empty_leaves_indices", |b| {
+        b.iter(|| {
+            tree.get_empty_leaves_indices();
+        })
+    });
 }

 criterion_group!(
--- a/utils/benches/poseidon_benchmark.rs
+++ b/utils/benches/poseidon_benchmark.rs
@@ -0,0 +1,65 @@
+use ark_bn254::Fr;
+use criterion::{
+    black_box, 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);
--- a/utils/src/merkle_tree/full_merkle_tree.rs
+++ b/utils/src/merkle_tree/full_merkle_tree.rs
@@ -3,12 +3,12 @@ use color_eyre::{Report, Result};
 use std::{
    cmp::max,
    fmt::Debug,
-    iter::{once, repeat, successors},
+    iter::{once, repeat_n, successors},
    str::FromStr,
 };

 ////////////////////////////////////////////////////////////
-/// Full Merkle Tree Implementation
+///// Full Merkle Tree Implementation
 ////////////////////////////////////////////////////////////

 /// Merkle tree with all leaf and intermediate hashes stored
@@ -26,6 +26,10 @@ pub struct FullMerkleTree<H: Hasher> {
    /// The tree nodes
    nodes: Vec<H::Fr>,

+    /// The indices of leaves which are set into zero upto next_index.
+    /// Set to 0 if the leaf is empty and set to 1 in otherwise.
+    cached_leaves_indices: Vec<u8>,
+
    // 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,
@@ -85,7 +89,7 @@ where
            .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);
@@ -96,6 +100,7 @@ where
            depth,
            cached_nodes,
            nodes,
+            cached_leaves_indices: vec![0; 1 << depth],
            next_index,
            metadata: Vec::new(),
        })
@@ -116,11 +121,10 @@ where
    }

    // Returns the total number of leaves set
-    fn leaves_set(&mut self) -> usize {
+    fn leaves_set(&self) -> usize {
        self.next_index
    }

-    #[must_use]
    // Returns the root of the tree
    fn root(&self) -> FrOf<Self::Hasher> {
        self.nodes[0]
@@ -141,6 +145,42 @@ where
        Ok(self.nodes[self.capacity() + leaf - 1])
    }

+    fn get_subtree_root(&self, n: usize, index: usize) -> Result<H::Fr> {
+        if n > self.depth() {
+            return Err(Report::msg("level exceeds depth size"));
+        }
+        if index >= self.capacity() {
+            return Err(Report::msg("index exceeds set size"));
+        }
+        if n == 0 {
+            Ok(self.root())
+        } else if n == self.depth {
+            self.get(index)
+        } else {
+            let mut idx = self.capacity() + index - 1;
+            let mut nd = self.depth;
+            loop {
+                let parent = self.parent(idx).unwrap();
+                nd -= 1;
+                if nd == n {
+                    return Ok(self.nodes[parent]);
+                } else {
+                    idx = parent;
+                    continue;
+                }
+            }
+        }
+    }
+    fn get_empty_leaves_indices(&self) -> Vec<usize> {
+        self.cached_leaves_indices
+            .iter()
+            .take(self.next_index)
+            .enumerate()
+            .filter(|&(_, &v)| v == 0u8)
+            .map(|(idx, _)| idx)
+            .collect()
+    }
+
    // Sets tree nodes, starting from start index
    // Function proper of FullMerkleTree implementation
    fn set_range<I: IntoIterator<Item = FrOf<Self::Hasher>>>(
@@ -158,6 +198,7 @@ where
        }
        hashes.into_iter().for_each(|hash| {
            self.nodes[index + count] = hash;
+            self.cached_leaves_indices[start + count] = 1;
            count += 1;
        });
        if count != 0 {
@@ -167,37 +208,36 @@ where
        Ok(())
    }

-    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, indices: J) -> Result<()>
    where
        I: IntoIterator<Item = FrOf<Self::Hasher>>,
        J: IntoIterator<Item = usize>,
    {
-        let index = self.capacity() + start - 1;
-        let mut count = 0;
-        let leaves = leaves.into_iter().collect::<Vec<_>>();
-        let to_remove_indices = to_remove_indices.into_iter().collect::<Vec<_>>();
-        // first count number of hashes, and check that they fit in the tree
-        // then insert into the tree
-        if leaves.len() + start - to_remove_indices.len() > self.capacity() {
-            return Err(Report::msg("provided hashes do not fit in the tree"));
+        let indices = indices.into_iter().collect::<Vec<_>>();
+        let min_index = *indices.first().unwrap();
+        let leaves_vec = leaves.into_iter().collect::<Vec<_>>();
+
+        let max_index = start + leaves_vec.len();
+
+        let mut set_values = vec![Self::Hasher::default_leaf(); max_index - min_index];
+
+        for i in min_index..start {
+            if !indices.contains(&i) {
+                let value = self.get(i)?;
+                set_values[i - min_index] = value;
+            }
        }

-        // remove leaves
-        for i in &to_remove_indices {
-            self.delete(*i)?;
+        for i in 0..leaves_vec.len() {
+            set_values[start - min_index + i] = leaves_vec[i];
        }

-        // insert new leaves
-        for hash in leaves {
-            self.nodes[index + count] = hash;
-            count += 1;
+        for i in indices {
+            self.cached_leaves_indices[i] = 0;
        }

-        if count != 0 {
-            self.update_nodes(index, index + (count - 1))?;
-            self.next_index = max(self.next_index, start + count - to_remove_indices.len());
-        }
-        Ok(())
+        self.set_range(start, set_values.into_iter())
+            .map_err(|e| Report::msg(e.to_string()))
    }

    // Sets a leaf at the next available index
@@ -211,11 +251,12 @@ where
        // 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())?;
+            self.cached_leaves_indices[index] = 0;
        }
        Ok(())
    }

-    // Computes a merkle proof the the leaf at the specified index
+    // Computes a merkle proof the leaf at the specified index
    fn proof(&self, leaf: usize) -> Result<FullMerkleProof<H>> {
        if leaf >= self.capacity() {
            return Err(Report::msg("index exceeds set size"));
@@ -299,14 +340,12 @@ 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,
@@ -314,7 +353,6 @@ 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
@@ -326,7 +364,6 @@ 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()
@@ -338,7 +375,6 @@ 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]),
--- a/Show More
+++ b/Show More