Use circom_witnesscalc crate (git)

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

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


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

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


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

----

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

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

.github/labels.yml

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

.github/workflows/ci.yml

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

.github/workflows/nightly-release.yml

@@ -8,10 +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
@@ -64,54 +72,21 @@ 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
-    steps:
-      - name: Checkout sources
-        uses: actions/checkout@v3
-      - name: Install stable toolchain
-        uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: stable
-          override: true
-      - uses: Swatinem/rust-cache@v2
-      - name: Install dependencies
-        run: make installdeps
-      - name: Install wasm-pack
-        uses: jetli/wasm-pack-action@v0.3.0
-      - name: cross make build
-        run: |
-          cross make build
-          mkdir release
-          cp pkg/** release/
-          tar -czvf browser-rln-wasm.tar.gz release/
-        working-directory: rln-wasm
-
-      - name: Upload archive artifact
-        uses: actions/upload-artifact@v2
-        with:
-          name: browser-rln-wasm-archive
-          path: rln-wasm/browser-rln-wasm.tar.gz
-          retention-days: 2
-
 
   prepare-prerelease:
     name: Prepare pre-release
-    needs: [linux, macos, browser-rln-wasm]
+    needs: [ linux, macos ]
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
@@ -119,8 +94,8 @@ 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 +117,7 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Delete artifacts
-        uses: geekyeggo/delete-artifact@v1
+        uses: geekyeggo/delete-artifact@v5
         with:
           failOnError: false
           name: |

.gitignore

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

Cargo.toml

@@ -1,5 +1,6 @@
 [workspace]
-members = ["rln", "rln-cli", "rln-wasm", "utils"]
+members = ["rln", "rln-cli", "utils"]
+default-members = ["rln", "rln-cli", "utils"]
 resolver = "2"
 
 # Compilation profile for any non-workspace member.
@@ -7,7 +8,3 @@ resolver = "2"
 # while having neglible impact on incremental build times.
 [profile.dev.package."*"]
 opt-level = 3
-
-[profile.release.package."rln-wasm"]
-# Tell `rustc` to optimize for small code size.
-opt-level = "s"

Makefile

@@ -13,15 +13,20 @@ endif
 
 installdeps: .pre-build
 ifeq ($(shell uname),Darwin)
-# commented due to https://github.com/orgs/Homebrew/discussions/4612	
-# @brew update 
+# commented due to https://github.com/orgs/Homebrew/discussions/4612
+# @brew update
 	@brew install cmake ninja
+	@git -C "wabt" pull || git clone --recursive https://github.com/WebAssembly/wabt.git "wabt"
+	@cd wabt && mkdir -p build && make
 else ifeq ($(shell uname),Linux)
 	@sudo apt-get update
 	@sudo apt-get install -y cmake ninja-build
+	@git -C "wabt" pull || git clone --recursive https://github.com/WebAssembly/wabt.git "wabt"
+	@cd wabt && mkdir -p build && cd build && cmake .. -GNinja && ninja && sudo ninja install
 endif
-	@git clone --recursive https://github.com/WebAssembly/wabt.git
-	@cd wabt && mkdir build && cd build && cmake .. -GNinja && ninja && sudo ninja install
+	# nvm already checks if it's installed, and no-ops if it is
+	@curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.7/install.sh | bash
+	@. ${HOME}/.nvm/nvm.sh && nvm install 18.20.2 && nvm use 18.20.2;
 
 build: .pre-build
 	@cargo make build

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
+```

rln-cli/Cargo.toml

@@ -1,13 +1,26 @@
 [package]
 name = "rln-cli"
-version = "0.3.0"
+version = "0.4.0"
 edition = "2021"
 
+[[example]]
+name = "relay"
+path = "src/examples/relay.rs"
+
+[[example]]
+name = "stateless"
+path = "src/examples/stateless.rs"
+required-features = ["stateless"]
+
 [dependencies]
-rln = { path = "../rln" }
-clap = { version = "4.2.7", features = ["cargo", "derive", "env"]}
-clap_derive = { version = "=4.2.0" }
-color-eyre = "=0.6.2"
-# serialization
-serde_json = "1.0.48"
-serde = { version = "1.0.130", features = ["derive"] }
+rln = { path = "../rln", default-features = true, features = ["pmtree-ft"] }
+zerokit_utils = { path = "../utils" }
+clap = { version = "4.5.29", features = ["cargo", "derive", "env"] }
+clap_derive = { version = "4.5.28" }
+color-eyre = "0.6.2"
+serde_json = "1.0.138"
+serde = { version = "1.0.217", features = ["derive"] }
+
+[features]
+arkzkey = ["rln/arkzkey"]
+stateless = ["rln/stateless"]

rln-cli/Makefile.toml

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

rln-cli/README.md

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

rln-cli/example.config.json

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

rln-cli/src/commands.rs

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

rln-cli/src/config.rs

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

rln-cli/src/examples/relay.rs

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

rln-cli/src/examples/stateless.rs

@@ -0,0 +1,313 @@
+#![cfg(feature = "stateless")]
+use std::{
+    collections::HashMap,
+    io::{stdin, stdout, Cursor, Write},
+};
+
+use clap::{Parser, Subcommand};
+use color_eyre::{eyre::eyre, Result};
+use rln::{
+    circuit::{Fr, TEST_TREE_HEIGHT},
+    hashers::{hash_to_field, poseidon_hash},
+    poseidon_tree::PoseidonTree,
+    protocol::{keygen, prepare_verify_input, rln_witness_from_values, serialize_witness},
+    public::RLN,
+    utils::{bytes_le_to_fr, fr_to_bytes_le},
+};
+use zerokit_utils::ZerokitMerkleTree;
+
+const MESSAGE_LIMIT: u32 = 1;
+
+type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
+
+#[derive(Parser)]
+#[command(author, version, about, long_about = None)]
+struct Cli {
+    #[command(subcommand)]
+    command: Commands,
+}
+
+#[derive(Subcommand)]
+enum Commands {
+    List,
+    Register,
+    Send {
+        #[arg(short, long)]
+        user_index: usize,
+        #[arg(short, long)]
+        message_id: u32,
+        #[arg(short, long)]
+        signal: String,
+    },
+    Clear,
+    Exit,
+}
+
+#[derive(Debug, Clone)]
+struct Identity {
+    identity_secret_hash: Fr,
+    id_commitment: Fr,
+}
+
+impl Identity {
+    fn new() -> Self {
+        let (identity_secret_hash, id_commitment) = keygen();
+        Identity {
+            identity_secret_hash,
+            id_commitment,
+        }
+    }
+}
+
+struct RLNSystem {
+    rln: RLN,
+    tree: PoseidonTree,
+    used_nullifiers: HashMap<[u8; 32], Vec<u8>>,
+    local_identities: HashMap<usize, Identity>,
+}
+
+impl RLNSystem {
+    fn new() -> Result<Self> {
+        let rln = RLN::new()?;
+        let default_leaf = Fr::from(0);
+        let tree = PoseidonTree::new(
+            TEST_TREE_HEIGHT,
+            default_leaf,
+            ConfigOf::<PoseidonTree>::default(),
+        )?;
+
+        Ok(RLNSystem {
+            rln,
+            tree,
+            used_nullifiers: HashMap::new(),
+            local_identities: HashMap::new(),
+        })
+    }
+
+    fn list_users(&self) {
+        if self.local_identities.is_empty() {
+            println!("No users registered yet.");
+            return;
+        }
+
+        println!("Registered users:");
+        for (index, identity) in &self.local_identities {
+            println!("User Index: {index}");
+            println!("+ Identity Secret Hash: {}", identity.identity_secret_hash);
+            println!("+ Identity Commitment: {}", identity.id_commitment);
+            println!();
+        }
+    }
+
+    fn register_user(&mut self) -> Result<usize> {
+        let index = self.tree.leaves_set();
+        let identity = Identity::new();
+
+        let rate_commitment = poseidon_hash(&[identity.id_commitment, Fr::from(MESSAGE_LIMIT)]);
+        self.tree.update_next(rate_commitment)?;
+
+        println!("Registered User Index: {index}");
+        println!("+ Identity secret hash: {}", identity.identity_secret_hash);
+        println!("+ Identity commitment: {}", identity.id_commitment);
+
+        self.local_identities.insert(index, identity);
+        Ok(index)
+    }
+
+    fn generate_proof(
+        &mut self,
+        user_index: usize,
+        message_id: u32,
+        signal: &str,
+        external_nullifier: Fr,
+    ) -> Result<Vec<u8>> {
+        let identity = match self.local_identities.get(&user_index) {
+            Some(identity) => identity,
+            None => return Err(eyre!("user index {user_index} not found")),
+        };
+
+        let merkle_proof = self.tree.proof(user_index)?;
+
+        let rln_witness = rln_witness_from_values(
+            identity.identity_secret_hash,
+            &merkle_proof,
+            hash_to_field(signal.as_bytes()),
+            external_nullifier,
+            Fr::from(MESSAGE_LIMIT),
+            Fr::from(message_id),
+        )?;
+
+        let serialized = serialize_witness(&rln_witness)?;
+        let mut input_buffer = Cursor::new(serialized);
+        let mut output_buffer = Cursor::new(Vec::new());
+
+        self.rln
+            .generate_rln_proof_with_witness(&mut input_buffer, &mut output_buffer)?;
+
+        println!("Proof generated successfully:");
+        println!("+ User Index: {user_index}");
+        println!("+ Message ID: {message_id}");
+        println!("+ Signal: {signal}");
+
+        Ok(output_buffer.into_inner())
+    }
+
+    fn verify_proof(&mut self, proof_data: Vec<u8>, signal: &str) -> Result<()> {
+        let proof_with_signal = prepare_verify_input(proof_data.clone(), signal.as_bytes());
+        let mut input_buffer = Cursor::new(proof_with_signal);
+
+        let root = self.tree.root();
+        let root_serialized = fr_to_bytes_le(&root);
+        let mut root_buffer = Cursor::new(root_serialized);
+
+        match self
+            .rln
+            .verify_with_roots(&mut input_buffer, &mut root_buffer)
+        {
+            Ok(true) => {
+                let nullifier = &proof_data[256..288];
+                let nullifier_key: [u8; 32] = nullifier.try_into()?;
+
+                if let Some(previous_proof) = self.used_nullifiers.get(&nullifier_key) {
+                    self.handle_duplicate_message_id(previous_proof.clone(), proof_data)?;
+                    return Ok(());
+                }
+                self.used_nullifiers.insert(nullifier_key, proof_data);
+                println!("Message verified and accepted");
+            }
+            Ok(false) => {
+                println!("Verification failed: message_id must be unique within the epoch and satisfy 0 <= message_id < MESSAGE_LIMIT: {MESSAGE_LIMIT}");
+            }
+            Err(err) => return Err(err.into()),
+        }
+        Ok(())
+    }
+
+    fn handle_duplicate_message_id(
+        &mut self,
+        previous_proof: Vec<u8>,
+        current_proof: Vec<u8>,
+    ) -> Result<()> {
+        let x = &current_proof[192..224];
+        let y = &current_proof[224..256];
+
+        let prev_x = &previous_proof[192..224];
+        let prev_y = &previous_proof[224..256];
+        if x == prev_x && y == prev_y {
+            return Err(eyre!("this exact message and signal has already been sent"));
+        }
+
+        let mut proof1 = Cursor::new(previous_proof);
+        let mut proof2 = Cursor::new(current_proof);
+        let mut output = Cursor::new(Vec::new());
+
+        match self
+            .rln
+            .recover_id_secret(&mut proof1, &mut proof2, &mut output)
+        {
+            Ok(_) => {
+                let output_data = output.into_inner();
+                let (leaked_identity_secret_hash, _) = bytes_le_to_fr(&output_data);
+
+                if let Some((user_index, identity)) = self
+                    .local_identities
+                    .iter()
+                    .find(|(_, identity)| {
+                        identity.identity_secret_hash == leaked_identity_secret_hash
+                    })
+                    .map(|(index, identity)| (*index, identity))
+                {
+                    let real_identity_secret_hash = identity.identity_secret_hash;
+                    if leaked_identity_secret_hash != real_identity_secret_hash {
+                        Err(eyre!("identity secret hash mismatch {leaked_identity_secret_hash} != {real_identity_secret_hash}"))
+                    } else {
+                        println!("DUPLICATE message ID detected! Reveal identity secret hash: {leaked_identity_secret_hash}");
+                        self.local_identities.remove(&user_index);
+                        println!("User index {user_index} has been SLASHED");
+                        Ok(())
+                    }
+                } else {
+                    Err(eyre!(
+                        "user identity secret hash {leaked_identity_secret_hash} not found"
+                    ))
+                }
+            }
+            Err(err) => Err(eyre!("Failed to recover identity secret: {err}")),
+        }
+    }
+}
+
+fn main() -> Result<()> {
+    println!("Initializing RLN instance...");
+    print!("\x1B[2J\x1B[1;1H");
+    let mut rln_system = RLNSystem::new()?;
+    let rln_epoch = hash_to_field(b"epoch");
+    let rln_identifier = hash_to_field(b"rln-identifier");
+    let external_nullifier = poseidon_hash(&[rln_epoch, rln_identifier]);
+    println!("RLN Stateless Relay Example:");
+    println!("Message Limit: {MESSAGE_LIMIT}");
+    println!("----------------------------------");
+    println!();
+    show_commands();
+
+    loop {
+        print!("\n> ");
+        stdout().flush()?;
+        let mut input = String::new();
+        stdin().read_line(&mut input)?;
+        let trimmed = input.trim();
+        let args = std::iter::once("").chain(trimmed.split_whitespace());
+
+        match Cli::try_parse_from(args) {
+            Ok(cli) => match cli.command {
+                Commands::List => {
+                    rln_system.list_users();
+                }
+                Commands::Register => {
+                    rln_system.register_user()?;
+                }
+                Commands::Send {
+                    user_index,
+                    message_id,
+                    signal,
+                } => {
+                    match rln_system.generate_proof(
+                        user_index,
+                        message_id,
+                        &signal,
+                        external_nullifier,
+                    ) {
+                        Ok(proof) => {
+                            if let Err(err) = rln_system.verify_proof(proof, &signal) {
+                                println!("Verification error: {err}");
+                            };
+                        }
+                        Err(err) => {
+                            println!("Proof generation error: {err}");
+                        }
+                    }
+                }
+                Commands::Clear => {
+                    print!("\x1B[2J\x1B[1;1H");
+                    show_commands();
+                }
+                Commands::Exit => {
+                    break;
+                }
+            },
+            Err(err) => {
+                eprintln!("Command error: {err}");
+            }
+        }
+    }
+    Ok(())
+}
+
+fn show_commands() {
+    println!("Available commands:");
+    println!("  list                                        - List registered users");
+    println!("  register                                    - Register a new user index");
+    println!("  send -u <index> -m <message_id> -s <signal> - Send a message with proof");
+    println!("  clear                                       - Clear the screen");
+    println!("  exit                                        - Exit the program");
+}

rln-cli/src/main.rs

@@ -1,9 +1,18 @@
-use std::{fs::File, io::Read, path::Path};
+use std::{
+    fs::File,
+    io::{Cursor, Read},
+    path::Path,
+};
 
 use clap::Parser;
-use color_eyre::{Report, Result};
+use color_eyre::{eyre::Report, Result};
 use commands::Commands;
-use rln::public::RLN;
+use config::{Config, InnerConfig};
+use rln::{
+    public::RLN,
+    utils::{bytes_le_to_fr, bytes_le_to_vec_fr},
+};
+use serde_json::json;
 use state::State;
 
 mod commands;
@@ -20,74 +29,97 @@ struct Cli {
 fn main() -> Result<()> {
     let cli = Cli::parse();
 
-    let mut state = State::load_state()?;
+    let mut state = match &cli.command {
+        Some(Commands::New { .. }) | Some(Commands::NewWithParams { .. }) => State::default(),
+        _ => State::load_state()?,
+    };
 
-    match &cli.command {
-        Some(Commands::New {
-            tree_height,
-            config,
-        }) => {
-            let resources = File::open(&config)?;
-            state.rln = Some(RLN::new(*tree_height, resources)?);
+    match cli.command {
+        Some(Commands::New { tree_height }) => {
+            let config = Config::load_config()?;
+            state.rln = if let Some(InnerConfig { tree_height, .. }) = config.inner {
+                println!("Initializing RLN with custom config");
+                Some(RLN::new(tree_height, Cursor::new(config.as_bytes()))?)
+            } else {
+                println!("Initializing RLN with default config");
+                Some(RLN::new(tree_height, Cursor::new(json!({}).to_string()))?)
+            };
             Ok(())
         }
         Some(Commands::NewWithParams {
             tree_height,
-            config,
-            tree_config_input,
+            resources_path,
         }) => {
             let mut resources: Vec<Vec<u8>> = Vec::new();
-            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);
             }
-            let tree_config_input_file = File::open(&tree_config_input)?;
-            state.rln = Some(RLN::new_with_params(
-                *tree_height,
-                resources[0].clone(),
-                resources[1].clone(),
-                resources[2].clone(),
-                tree_config_input_file,
-            )?);
+            let config = Config::load_config()?;
+            if let Some(InnerConfig {
+                tree_height,
+                tree_config,
+            }) = config.inner
+            {
+                println!("Initializing RLN with custom config");
+                state.rln = Some(RLN::new_with_params(
+                    tree_height,
+                    resources[0].clone(),
+                    resources[1].clone(),
+                    Cursor::new(tree_config.to_string().as_bytes()),
+                )?)
+            } else {
+                println!("Initializing RLN with default config");
+                state.rln = Some(RLN::new_with_params(
+                    tree_height,
+                    resources[0].clone(),
+                    resources[1].clone(),
+                    Cursor::new(json!({}).to_string()),
+                )?)
+            };
             Ok(())
         }
         Some(Commands::SetTree { tree_height }) => {
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
-                .set_tree(*tree_height)?;
+                .set_tree(tree_height)?;
             Ok(())
         }
-        Some(Commands::SetLeaf { index, file }) => {
-            let input_data = File::open(&file)?;
+        Some(Commands::SetLeaf { index, input }) => {
+            let input_data = File::open(input)?;
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
-                .set_leaf(*index, input_data)?;
+                .set_leaf(index, input_data)?;
             Ok(())
         }
-        Some(Commands::SetMultipleLeaves { index, file }) => {
-            let input_data = File::open(&file)?;
+        Some(Commands::SetMultipleLeaves { index, input }) => {
+            let input_data = File::open(input)?;
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
-                .set_leaves_from(*index, input_data)?;
+                .set_leaves_from(index, input_data)?;
             Ok(())
         }
-        Some(Commands::ResetMultipleLeaves { file }) => {
-            let input_data = File::open(&file)?;
+        Some(Commands::ResetMultipleLeaves { input }) => {
+            let input_data = File::open(input)?;
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
                 .init_tree_with_leaves(input_data)?;
             Ok(())
         }
-        Some(Commands::SetNextLeaf { file }) => {
-            let input_data = File::open(&file)?;
+        Some(Commands::SetNextLeaf { input }) => {
+            let input_data = File::open(input)?;
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
@@ -98,60 +130,73 @@ fn main() -> Result<()> {
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
-                .delete_leaf(*index)?;
-            Ok(())
-        }
-        Some(Commands::GetRoot) => {
-            let writer = std::io::stdout();
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .get_root(writer)?;
-            Ok(())
-        }
-        Some(Commands::GetProof { index }) => {
-            let writer = std::io::stdout();
-            state
-                .rln
-                .ok_or(Report::msg("no RLN instance initialized"))?
-                .get_proof(*index, writer)?;
+                .delete_leaf(index)?;
             Ok(())
         }
         Some(Commands::Prove { input }) => {
-            let input_data = File::open(&input)?;
-            let writer = std::io::stdout();
+            let input_data = File::open(input)?;
+            let mut output_buffer = Cursor::new(Vec::<u8>::new());
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
-                .prove(input_data, writer)?;
+                .prove(input_data, &mut output_buffer)?;
+            let proof = output_buffer.into_inner();
+            println!("proof: {:?}", proof);
             Ok(())
         }
-        Some(Commands::Verify { file }) => {
-            let input_data = File::open(&file)?;
-            state
+        Some(Commands::Verify { input }) => {
+            let input_data = File::open(input)?;
+            let verified = state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
                 .verify(input_data)?;
+            println!("verified: {:?}", verified);
             Ok(())
         }
         Some(Commands::GenerateProof { input }) => {
-            let input_data = File::open(&input)?;
-            let writer = std::io::stdout();
+            let input_data = File::open(input)?;
+            let mut output_buffer = Cursor::new(Vec::<u8>::new());
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
-                .generate_rln_proof(input_data, writer)?;
+                .generate_rln_proof(input_data, &mut output_buffer)?;
+            let proof = output_buffer.into_inner();
+            println!("proof: {:?}", proof);
             Ok(())
         }
         Some(Commands::VerifyWithRoots { input, roots }) => {
-            let input_data = File::open(&input)?;
-            let roots_data = File::open(&roots)?;
+            let input_data = File::open(input)?;
+            let roots_data = File::open(roots)?;
             state
                 .rln
                 .ok_or(Report::msg("no RLN instance initialized"))?
                 .verify_with_roots(input_data, roots_data)?;
             Ok(())
         }
+        Some(Commands::GetRoot) => {
+            let mut output_buffer = Cursor::new(Vec::<u8>::new());
+            state
+                .rln
+                .ok_or(Report::msg("no RLN instance initialized"))?
+                .get_root(&mut output_buffer)
+                .unwrap();
+            let (root, _) = bytes_le_to_fr(&output_buffer.into_inner());
+            println!("root: {root}");
+            Ok(())
+        }
+        Some(Commands::GetProof { index }) => {
+            let mut output_buffer = Cursor::new(Vec::<u8>::new());
+            state
+                .rln
+                .ok_or(Report::msg("no RLN instance initialized"))?
+                .get_proof(index, &mut output_buffer)?;
+            let output_buffer_inner = output_buffer.into_inner();
+            let (path_elements, _) = bytes_le_to_vec_fr(&output_buffer_inner)?;
+            for (index, element) in path_elements.iter().enumerate() {
+                println!("path element {}: {}", index, element);
+            }
+            Ok(())
+        }
         None => Ok(()),
     }
 }

rln-cli/src/state.rs

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

rln-wasm/.gitignore

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

rln-wasm/Cargo.toml

@@ -1,33 +0,0 @@
-[package]
-name = "rln-wasm"
-version = "0.0.13"
-edition = "2021"
-license = "MIT or Apache2"
-
-[lib]
-crate-type = ["cdylib", "rlib"]
-
-[features]
-default = ["console_error_panic_hook"]
-
-[dependencies]
-rln = { path = "../rln", default-features = false, features = ["wasm"] }
-num-bigint = { version = "0.4", default-features = false, features = ["rand", "serde"] }
-wasmer = { version = "2.3", default-features = false, features = ["js", "std"] }
-web-sys = {version = "0.3", features=["console"]}
-getrandom = { version = "0.2.7", default-features = false, features = ["js"] }
-wasm-bindgen = "0.2.63"
-serde-wasm-bindgen = "0.4"
-js-sys = "0.3.59"
-serde_json = "1.0.85"
-
-# The `console_error_panic_hook` crate provides better debugging of panics by
-# logging them with `console.error`. This is great for development, but requires
-# all the `std::fmt` and `std::panicking` infrastructure, so isn't great for
-# code size when deploying.
-console_error_panic_hook = { version = "0.1.7", optional = true }
-
-[dev-dependencies]
-wasm-bindgen-test = "0.3.13"
-wasm-bindgen-futures = "0.4.33"
-

rln-wasm/Makefile.toml

@@ -1,31 +0,0 @@
-[tasks.pack-build]
-command = "wasm-pack"
-args = ["build", "--release", "--target", "web", "--scope", "waku"]
-
-[tasks.pack-rename]
-script = "sed -i.bak 's/rln-wasm/zerokit-rln-wasm/g' pkg/package.json && rm pkg/package.json.bak"
-
-[tasks.build]
-clear = true
-dependencies = [
-    "pack-build",
-    "pack-rename",
-    "post-build"
-]
-
-[tasks.post-build]
-command = "wasm-strip"
-args = ["./pkg/rln_wasm_bg.wasm"]
-
-[tasks.test]
-command = "wasm-pack"
-args = ["test", "--release", "--node"]
-dependencies = ["build"]
-
-[tasks.login]
-command = "wasm-pack"
-args = ["login"]
-
-[tasks.publish]
-command = "wasm-pack"
-args = ["publish", "--access", "public", "--target", "web"]

rln-wasm/README.md

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

rln-wasm/resources/witness_calculator.js

@@ -1,331 +0,0 @@
-module.exports = async function builder(code, options) {
-
-    options = options || {};
-
-    let wasmModule;
-    try {
-	wasmModule = await WebAssembly.compile(code);
-    }  catch (err) {
-	console.log(err);
-	console.log("\nTry to run circom --c in order to generate c++ code instead\n");
-	throw new Error(err);
-    }
-
-    let wc;
-
-    let errStr = "";
-    let msgStr = "";
-    
-    const instance = await WebAssembly.instantiate(wasmModule, {
-        runtime: {
-            exceptionHandler : function(code) {
-		let err;
-                if (code == 1) {
-                    err = "Signal not found.\n";
-                } else if (code == 2) {
-                    err = "Too many signals set.\n";
-                } else if (code == 3) {
-                    err = "Signal already set.\n";
-		} else if (code == 4) {
-                    err = "Assert Failed.\n";
-		} else if (code == 5) {
-                    err = "Not enough memory.\n";
-		} else if (code == 6) {
-                    err = "Input signal array access exceeds the size.\n";
-		} else {
-		    err = "Unknown error.\n";
-                }
-                throw new Error(err + errStr);
-            },
-	    printErrorMessage : function() {
-		errStr += getMessage() + "\n";
-                // console.error(getMessage());
-	    },
-	    writeBufferMessage : function() {
-			const msg = getMessage();
-			// Any calls to `log()` will always end with a `\n`, so that's when we print and reset
-			if (msg === "\n") {
-				console.log(msgStr);
-				msgStr = "";
-			} else {
-				// If we've buffered other content, put a space in between the items
-				if (msgStr !== "") {
-					msgStr += " "
-				}
-				// Then append the message to the message we are creating
-				msgStr += msg;
-			}
-	    },
-	    showSharedRWMemory : function() {
-		printSharedRWMemory ();
-            }
-
-        }
-    });
-
-    const sanityCheck =
-        options
-//        options &&
-//        (
-//            options.sanityCheck ||
-//            options.logGetSignal ||
-//            options.logSetSignal ||
-//            options.logStartComponent ||
-//            options.logFinishComponent
-//        );
-
-    
-    wc = new WitnessCalculator(instance, sanityCheck);
-    return wc;
-
-    function getMessage() {
-        var message = "";
-	var c = instance.exports.getMessageChar();
-        while ( c != 0 ) {
-	    message += String.fromCharCode(c);
-	    c = instance.exports.getMessageChar();
-	}
-        return message;
-    }
-	
-    function printSharedRWMemory () {
-	const shared_rw_memory_size = instance.exports.getFieldNumLen32();
-	const arr = new Uint32Array(shared_rw_memory_size);
-	for (let j=0; j<shared_rw_memory_size; j++) {
-	    arr[shared_rw_memory_size-1-j] = instance.exports.readSharedRWMemory(j);
-	}
-
-	// If we've buffered other content, put a space in between the items
-	if (msgStr !== "") {
-		msgStr += " "
-	}
-	// Then append the value to the message we are creating
-	msgStr += (fromArray32(arr).toString());
-	}
-
-};
-
-class WitnessCalculator {
-    constructor(instance, sanityCheck) {
-        this.instance = instance;
-
-	this.version = this.instance.exports.getVersion();
-        this.n32 = this.instance.exports.getFieldNumLen32();
-
-        this.instance.exports.getRawPrime();
-        const arr = new Uint32Array(this.n32);
-        for (let i=0; i<this.n32; i++) {
-            arr[this.n32-1-i] = this.instance.exports.readSharedRWMemory(i);
-        }
-        this.prime = fromArray32(arr);
-
-        this.witnessSize = this.instance.exports.getWitnessSize();
-
-        this.sanityCheck = sanityCheck;
-    }
-    
-    circom_version() {
-	return this.instance.exports.getVersion();
-    }
-
-    async _doCalculateWitness(input, sanityCheck) {
-	//input is assumed to be a map from signals to arrays of bigints
-        this.instance.exports.init((this.sanityCheck || sanityCheck) ? 1 : 0);
-        const keys = Object.keys(input);
-	var input_counter = 0;
-        keys.forEach( (k) => {
-            const h = fnvHash(k);
-            const hMSB = parseInt(h.slice(0,8), 16);
-            const hLSB = parseInt(h.slice(8,16), 16);
-            const fArr = flatArray(input[k]);
-	    let signalSize = this.instance.exports.getInputSignalSize(hMSB, hLSB);
-	    if (signalSize < 0){
-		throw new Error(`Signal ${k} not found\n`);
-	    }
-	    if (fArr.length < signalSize) {
-		throw new Error(`Not enough values for input signal ${k}\n`);
-	    }
-	    if (fArr.length > signalSize) {
-		throw new Error(`Too many values for input signal ${k}\n`);
-	    }
-            for (let i=0; i<fArr.length; i++) {
-                const arrFr = toArray32(BigInt(fArr[i])%this.prime,this.n32)
-                for (let j=0; j<this.n32; j++) {
-		    this.instance.exports.writeSharedRWMemory(j,arrFr[this.n32-1-j]);
-		}
-		try {
-                    this.instance.exports.setInputSignal(hMSB, hLSB,i);
-		    input_counter++;
-		} catch (err) {
-		    // console.log(`After adding signal ${i} of ${k}`)
-                    throw new Error(err);
-		}
-            }
-
-        });
-	if (input_counter < this.instance.exports.getInputSize()) {
-	    throw new Error(`Not all inputs have been set. Only ${input_counter} out of ${this.instance.exports.getInputSize()}`);
-	}
-    }
-
-    async calculateWitness(input, sanityCheck) {
-
-        const w = [];
-
-        await this._doCalculateWitness(input, sanityCheck);
-
-        for (let i=0; i<this.witnessSize; i++) {
-            this.instance.exports.getWitness(i);
-	    const arr = new Uint32Array(this.n32);
-            for (let j=0; j<this.n32; j++) {
-            arr[this.n32-1-j] = this.instance.exports.readSharedRWMemory(j);
-            }
-            w.push(fromArray32(arr));
-        }
-
-        return w;
-    }
-    
-
-    async calculateBinWitness(input, sanityCheck) {
-
-        const buff32 = new Uint32Array(this.witnessSize*this.n32);
-	const buff = new  Uint8Array( buff32.buffer);
-        await this._doCalculateWitness(input, sanityCheck);
-
-        for (let i=0; i<this.witnessSize; i++) {
-            this.instance.exports.getWitness(i);
-	    const pos = i*this.n32;
-            for (let j=0; j<this.n32; j++) {
-		buff32[pos+j] = this.instance.exports.readSharedRWMemory(j);
-            }
-        }
-
-	return buff;
-    }
-    
-
-    async calculateWTNSBin(input, sanityCheck) {
-
-        const buff32 = new Uint32Array(this.witnessSize*this.n32+this.n32+11);
-	const buff = new  Uint8Array( buff32.buffer);
-        await this._doCalculateWitness(input, sanityCheck);
-  
-	//"wtns"
-	buff[0] = "w".charCodeAt(0)
-	buff[1] = "t".charCodeAt(0)
-	buff[2] = "n".charCodeAt(0)
-	buff[3] = "s".charCodeAt(0)
-
-	//version 2
-	buff32[1] = 2;
-
-	//number of sections: 2
-	buff32[2] = 2;
-
-	//id section 1
-	buff32[3] = 1;
-
-	const n8 = this.n32*4;
-	//id section 1 length in 64bytes
-	const idSection1length = 8 + n8;
-	const idSection1lengthHex = idSection1length.toString(16);
-        buff32[4] = parseInt(idSection1lengthHex.slice(0,8), 16);
-        buff32[5] = parseInt(idSection1lengthHex.slice(8,16), 16);
-
-	//this.n32
-	buff32[6] = n8;
-
-	//prime number
-	this.instance.exports.getRawPrime();
-
-	var pos = 7;
-        for (let j=0; j<this.n32; j++) {
-	    buff32[pos+j] = this.instance.exports.readSharedRWMemory(j);
-        }
-	pos += this.n32;
-
-	// witness size
-	buff32[pos] = this.witnessSize;
-	pos++;
-
-	//id section 2
-	buff32[pos] = 2;
-	pos++;
-
-	// section 2 length
-	const idSection2length = n8*this.witnessSize;
-	const idSection2lengthHex = idSection2length.toString(16);
-        buff32[pos] = parseInt(idSection2lengthHex.slice(0,8), 16);
-        buff32[pos+1] = parseInt(idSection2lengthHex.slice(8,16), 16);
-
-	pos += 2;
-        for (let i=0; i<this.witnessSize; i++) {
-            this.instance.exports.getWitness(i);
-            for (let j=0; j<this.n32; j++) {
-		buff32[pos+j] = this.instance.exports.readSharedRWMemory(j);
-            }
-	    pos += this.n32;
-        }
-
-	return buff;
-    }
-
-}
-
-
-function toArray32(rem,size) {
-    const res = []; //new Uint32Array(size); //has no unshift
-    const radix = BigInt(0x100000000);
-    while (rem) {
-        res.unshift( Number(rem % radix));
-        rem = rem / radix;
-    }
-    if (size) {
-	var i = size - res.length;
-	while (i>0) {
-	    res.unshift(0);
-	    i--;
-	}
-    }
-    return res;
-}
-
-function fromArray32(arr) { //returns a BigInt
-    var res = BigInt(0);
-    const radix = BigInt(0x100000000);
-    for (let i = 0; i<arr.length; i++) {
-        res = res*radix + BigInt(arr[i]);
-    }
-    return res;
-}
-
-function flatArray(a) {
-    var res = [];
-    fillArray(res, a);
-    return res;
-
-    function fillArray(res, a) {
-        if (Array.isArray(a)) {
-            for (let i=0; i<a.length; i++) {
-                fillArray(res, a[i]);
-            }
-        } else {
-            res.push(a);
-        }
-    }
-}
-
-function fnvHash(str) {
-    const uint64_max = BigInt(2) ** BigInt(64);
-    let hash = BigInt("0xCBF29CE484222325");
-    for (var i = 0; i < str.length; i++) {
-	hash ^= BigInt(str[i].charCodeAt());
-	hash *= BigInt(0x100000001B3);
-	hash %= uint64_max;
-    }
-    let shash = hash.toString(16);
-    let n = 16 - shash.length;
-    shash = '0'.repeat(n).concat(shash);
-    return shash;
-}

rln-wasm/src/lib.rs

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

rln-wasm/src/utils.js

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

rln-wasm/tests/rln-wasm.rs

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

rln/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rln"
-version = "0.4.3"
+version = "0.7.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
@@ -15,56 +15,67 @@ bench = false
 # This flag disable cargo doctests, i.e. testing example code-snippets in documentation
 doctest = false
 
-
 [dependencies]
 # ZKP Generation
-ark-ec = { version = "=0.4.1", default-features = false }
-ark-ff = { version = "=0.4.1", default-features = false, features = ["asm"] }
-ark-std = { version = "=0.4.0", default-features = false }
-ark-bn254 = { version = "=0.4.0" }
-ark-groth16 = { version = "=0.4.0", features = [
+ark-bn254 = { version = "0.5.0", features = ["std"] }
+ark-ff = { version = "0.5.0", features = ["std", "asm"] }
+ark-serialize = { version = "0.5.0", features = ["derive"] }
+ark-ec = { version = "0.5.0", default-features = false }
+ark-std = { version = "0.5.0", default-features = false }
+ark-groth16 = { version = "0.5.0", features = [
     "parallel",
 ], default-features = false }
-ark-relations = { version = "=0.4.0", default-features = false, features = [
+ark-relations = { version = "0.5.0", default-features = false, features = [
     "std",
 ] }
-ark-serialize = { version = "=0.4.1", default-features = false }
-ark-circom = { version = "=0.1.0", default-features = false, features = [
-    "circom-2",
-] }
+ark-circom = { version = "0.5.0" }
+ark-r1cs-std = { version = "0.5.0" }
+# circom-witnesscalc = { git = "https://github.com/iden3/circom-witnesscalc", branch = "main" }
+# Dec 8, 2024 (Note: name is circom_XX and not circom-X in this git rev id)
+circom_witnesscalc = { git = "https://github.com/iden3/circom-witnesscalc", rev = "5cb365b6e4d9052ecc69d4567fcf5bc061c20e94" }
+# Dec 16, 2024
+# circom_witnesscalc = { git = "https://github.com/iden3/circom-witnesscalc", rev = "bdc15673f7351a1792342e68c659b78d4b327425" }
+# Jan 31, 2025
+# circom_witnesscalc = { git = "https://github.com/iden3/circom-witnesscalc", rev = "cec2cdefad044e5c6b796db75267901cc2e6fd6b" }
+# Last (e.g. March 23, 2025 - latest)
+# circom-witnesscalc = { git = "https://github.com/iden3/circom-witnesscalc", rev = "de9e6f15800d3f37e5d60da4dbc8e07b49c815e6" }
 
-# WASM
-wasmer = { version = "=2.3.0", default-features = false }
+# local path
+# circom-witnesscalc = { path = "../../circom-witnesscalc" }
+# circom_witnesscalc = { path = "../../circom-witnesscalc" }
 
 # error handling
-color-eyre = "=0.6.2"
-thiserror = "=1.0.39"
+color-eyre = "0.6.2"
+thiserror = "2.0.11"
 
 # utilities
-cfg-if = "=1.0"
-num-bigint = { version = "=0.4.3", default-features = false, features = [
+byteorder = "1.4.3"
+cfg-if = "1.0"
+num-bigint = { version = "0.4.6", default-features = false, features = [
     "rand",
 ] }
-num-traits = "=0.2.15"
-once_cell = "=1.17.1"
-rand = "=0.8.5"
-rand_chacha = "=0.3.1"
-tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
-utils = { package = "zerokit_utils", version = "=0.4.3", path = "../utils/", default-features = false }
-
+num-traits = "0.2.19"
+once_cell = "1.19.0"
+lazy_static = "1.4.0"
+rand = "0.8.5"
+rand_chacha = "0.3.1"
+ruint = { version = "1.12.4", features = ["rand", "serde", "ark-ff-04"] }
+tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+utils = { package = "zerokit_utils", version = "0.5.2", path = "../utils/", default-features = false }
 
 # serialization
-serde_json = "=1.0.96"
-serde = { version = "=1.0.163", features = ["derive"] }
+prost = "0.13.1"
+serde_json = "1.0"
+serde = { version = "1.0", features = ["derive"] }
 
-include_dir = "=0.7.3"
+document-features = { version = "=0.2.10", optional = true }
 
 [dev-dependencies]
-sled = "=0.34.7"
-criterion = { version = "=0.4.0", features = ["html_reports"] }
+sled = "0.34.7"
+criterion = { version = "0.4.0", features = ["html_reports"] }
 
 [features]
-default = ["parallel", "wasmer/sys-default", "pmtree-ft"]
+default = ["parallel", "pmtree-ft"]
 parallel = [
     "ark-ec/parallel",
     "ark-ff/parallel",
@@ -72,8 +83,9 @@ parallel = [
     "ark-groth16/parallel",
     "utils/parallel",
 ]
-wasm = ["wasmer/js", "wasmer/std"]
 fullmerkletree = ["default"]
+arkzkey = []
+stateless = []
 
 # Note: pmtree feature is still experimental
 pmtree-ft = ["utils/pmtree-ft"]
@@ -81,3 +93,23 @@ pmtree-ft = ["utils/pmtree-ft"]
 [[bench]]
 name = "pmtree_benchmark"
 harness = false
+
+[[bench]]
+name = "circuit_loading_benchmark"
+harness = false
+
+[[bench]]
+name = "circuit_loading_arkzkey_benchmark"
+harness = false
+required-features = ["arkzkey"]
+
+[[bench]]
+name = "poseidon_tree_benchmark"
+harness = false
+
+[[bench]]
+name = "calc_witness_benchmark"
+harness = false
+
+[package.metadata.docs.rs]
+all-features = true

rln/Makefile.toml

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

rln/README.md

@@ -1,64 +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 2 [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) RLN circuits having Merkle tree of height `20` and `32`, respectively.
-
-## Getting started
+> [!IMPORTANT]
+> Version 0.6.1 is required for WASM support or x32 architecture. Current version doesn't support these platforms due to dependency issues. WASM support will return in a future release.
 
 ### Add RLN as dependency
 
@@ -69,130 +22,260 @@ 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_verify_input},
+    public::RLN,
+    utils::{fr_to_bytes_le, normalize_usize},
+};
+use serde_json::json;
 
-// We create a new RLN instance
-let mut rln = RLN::new(tree_height, 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 = 10;
+    let rate_commitment = poseidon_hash(&[id_commitment, Fr::from(user_message_limit)]);
+    let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
+    rln.set_leaf(id_index, &mut buffer).unwrap();
+
+    // 4. Set up external nullifier (epoch + app identifier)
+    // We generate epoch from a date seed and we ensure is
+    // mapped to a field element by hashing-to-field its content
+    let epoch = hash_to_field(b"Today at noon, this year");
+    // We generate rln_identifier from a date seed and we ensure is
+    // mapped to a field element by hashing-to-field its content
+    let rln_identifier = hash_to_field(b"test-rln-identifier");
+    let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+
+    // 5. Generate and verify a proof for a message
+    let signal = b"RLN is awesome";
+
+    // 6. Prepare input for generate_rln_proof API
+    // input_data is [ identity_secret<32> | id_index<8> | external_nullifier<32> | user_message_limit<32> | message_id<32> | signal_len<8> | signal<var> ]
+    let mut serialized: Vec<u8> = Vec::new();
+    serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
+    serialized.append(&mut normalize_usize(id_index));
+    serialized.append(&mut fr_to_bytes_le(&Fr::from(user_message_limit)));
+    serialized.append(&mut fr_to_bytes_le(&Fr::from(1)));
+    serialized.append(&mut fr_to_bytes_le(&external_nullifier));
+    serialized.append(&mut normalize_usize(signal.len()));
+    serialized.append(&mut signal.to_vec());
+
+    // 7. Generate a RLN proof
+    // We generate a RLN proof for proof_input
+    let mut input_buffer = Cursor::new(serialized);
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
+        .unwrap();
+
+    // We get the public outputs returned by the circuit evaluation
+    // The byte vector `proof_data` is serialized as `[ zk-proof | tree_root | external_nullifier | share_x | share_y | nullifier ]`.
+    let proof_data = output_buffer.into_inner();
+
+    // 8. Verify a RLN proof
+    // Input buffer is serialized as `[proof_data | signal_len | signal ]`, where `proof_data` is (computed as) the output obtained by `generate_rln_proof`.
+    let verify_data = prepare_verify_input(proof_data, signal);
+
+    // We verify the zk-proof against the provided proof values
+    let mut input_buffer = Cursor::new(verify_data);
+    let verified = rln.verify_rln_proof(&mut input_buffer).unwrap();
+
+    // We ensure the proof is valid
+    assert!(verified);
+}
 ```
 
-### Generate an identity keypair
+### 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 identity_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 Rate commitment to the RLN Merkle tree
+### Build Commands
 
-```rust
-// We define the tree index where id_commitment will be added
-let id_index = 10;
-let user_message_limit = 10;
+```sh
+# Build with default features
+cargo make build
 
-// We serialize id_commitment and pass it to set_leaf
-let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
-let mut buffer = Cursor::new(serialize_field_element(rate_commitment));
-rln.set_leaf(id_index, &mut buffer).unwrap();
+# 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 | rln_identifier | user_message_limit | message_id | 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, rln_identifier, user_message_limit, message_id, 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

rln/benches/calc_witness_benchmark.rs

@@ -0,0 +1,83 @@
+use std::time::Duration;
+use criterion::{criterion_group, criterion_main, Criterion, BenchmarkId};
+
+use rln::circuit::{calc_witness_2, calculate_rln_witness, graph_from_folder, zkey_from_folder, Fr, TEST_TREE_HEIGHT};
+use rln::hashers::{hash_to_field, poseidon_hash};
+use rln::iden3calc::calc_witness;
+use rln::poseidon_tree::PoseidonTree;
+use rln::protocol::{inputs_for_witness_calculation, keygen, rln_witness_from_json, rln_witness_from_values, rln_witness_to_json, RLNWitnessInput};
+use utils::ZerokitMerkleTree;
+
+type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
+
+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()
+}
+
+fn bench_calc_witness(c: &mut Criterion) {
+
+    // We generate all relevant keys
+    let proving_key = zkey_from_folder();
+    // let verification_key = &proving_key.0.vk;
+    let graph_data = graph_from_folder();
+    // We compute witness from the json input
+    let rln_witness = get_test_witness();
+    let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
+    // let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
+
+    let inputs_1 = inputs_for_witness_calculation(&rln_witness)
+        .unwrap()
+        .into_iter()
+        .map(|(name, values)| (name.to_string(), values));
+    let inputs_2 = inputs_for_witness_calculation(&rln_witness)
+        .unwrap()
+        .into_iter()
+        .map(|(name, values)| (name.to_string(), values));
+
+    let mut group = c.benchmark_group("calc_witness");
+    // group.sample_size(50);
+    group.measurement_time(Duration::from_secs(11));
+    group.bench_function("Circom-witnesscalc current", |b| b.iter(|| calc_witness(inputs_1.clone(), graph_data) ));
+    // group.bench_function("Circom-witnesscalc crate(git)", |b| b.iter(|| calculate_rln_witness(inputs, graph_data) ));
+    group.bench_function("Circom-witnesscalc crate(git)", |b| b.iter(|| calc_witness_2(inputs_2.clone(), graph_data) ));
+    
+    group.finish();
+}
+
+criterion_group!(benches, bench_calc_witness);
+criterion_main!(benches);
+

rln/benches/circuit_loading_arkzkey_benchmark.rs

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

rln/benches/circuit_loading_benchmark.rs

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

rln/benches/pmtree_benchmark.rs

@@ -1,7 +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();
@@ -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);

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);

rln/resources/tree_height_20/verification_key.json

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

rln/resources/tree_height_32/verification_key.json

@@ -1,114 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 5,
- "vk_alpha_1": [
-  "20491192805390485299153009773594534940189261866228447918068658471970481763042",
-  "9383485363053290200918347156157836566562967994039712273449902621266178545958",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "6375614351688725206403948262868962793625744043794305715222011528459656738731",
-   "4252822878758300859123897981450591353533073413197771768651442665752259397132"
-  ],
-  [
-   "10505242626370262277552901082094356697409835680220590971873171140371331206856",
-   "21847035105528745403288232691147584728191162732299865338377159692350059136679"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "3689226096868373144622340732612563195789744807442014147637039988348252818659",
-   "18947459102520510468597269280688700807407684209892273827108603062925288762423"
-  ],
-  [
-   "5816405977664254142436796931495067997250259145480168934320978750042633353708",
-   "14555486789839131710516067578112557185806110684461247253491378577062852578892"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "2029413683389138792403550203267699914886160938906632433982220835551125967885",
-    "21072700047562757817161031222997517981543347628379360635925549008442030252106"
-   ],
-   [
-    "5940354580057074848093997050200682056184807770593307860589430076672439820312",
-    "12156638873931618554171829126792193045421052652279363021382169897324752428276"
-   ],
-   [
-    "7898200236362823042373859371574133993780991612861777490112507062703164551277",
-    "7074218545237549455313236346927434013100842096812539264420499035217050630853"
-   ]
-  ],
-  [
-   [
-    "7077479683546002997211712695946002074877511277312570035766170199895071832130",
-    "10093483419865920389913245021038182291233451549023025229112148274109565435465"
-   ],
-   [
-    "4595479056700221319381530156280926371456704509942304414423590385166031118820",
-    "19831328484489333784475432780421641293929726139240675179672856274388269393268"
-   ],
-   [
-    "11934129596455521040620786944827826205713621633706285934057045369193958244500",
-    "8037395052364110730298837004334506829870972346962140206007064471173334027475"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "5412646265162057015134786739992128493053406364679846617542694915593022919217",
-   "9665511386935901867415947590751330959748921059696950821222365265700369811120",
-   "1"
-  ],
-  [
-   "4294362651275803035824711662252687124584574009834787359330648404293309808795",
-   "1861758671717754835450145961645465880215655915164196594175485865489885224285",
-   "1"
-  ],
-  [
-   "1911114017568107170522785254288953144010421698038439931935418407428234018676",
-   "13761363892532562822351086117281964648116890138564516558345965908415019790129",
-   "1"
-  ],
-  [
-   "16312980235585837964428386585067529342038135099260965575497230302984635878053",
-   "20286500347141875536561618770383759234192052027362539966911091298688849002783",
-   "1"
-  ],
-  [
-   "21038649368092225315431823433752123495654049075935052064397443455654061176031",
-   "6976971039866104284556300526186000690370678593992968176463280189048347216392",
-   "1"
-  ],
-  [
-   "971745799362951123575710699973701411260115357326598060711339429906895409324",
-   "12959821343398475313407440786226277845673045139874184400082186049649123071798",
-   "1"
-  ]
- ]
-}

rln/src/circuit.rs

@@ -1,43 +1,52 @@
 // This crate provides interfaces for the zero-knowledge circuit and keys
 
+use std::collections::HashMap;
+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_circom::read_zkey;
+use ark_ff::{BigInteger, PrimeField};
 use ark_groth16::{ProvingKey, VerifyingKey};
 use ark_relations::r1cs::ConstraintMatrices;
 use cfg_if::cfg_if;
+use circom_witnesscalc::{calc_witness, deserialize_inputs, graph, Error, InputSignalsInfo};
+use circom_witnesscalc::graph::Node;
+use circom_witnesscalc::storage::deserialize_witnesscalc_graph;
 use color_eyre::{Report, Result};
-use num_bigint::BigUint;
-use serde_json::Value;
-use std::io::Cursor;
-use std::str::FromStr;
+use ruint::aliases::U256;
+// use crate::iden3calc::calc_witness;
+use crate::iden3calc::graph::{fr_to_u256, u256_to_fr};
 
-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;
-    }
+#[cfg(feature = "arkzkey")]
+use {
+    ark_ff::Field, ark_serialize::CanonicalDeserialize, ark_serialize::CanonicalSerialize,
+    color_eyre::eyre::WrapErr,
+};
+
+#[cfg(not(feature = "arkzkey"))]
+use {ark_circom::read_zkey, std::io::Cursor};
+
+#[cfg(feature = "arkzkey")]
+pub const ARKZKEY_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/rln_final.arkzkey");
+
+pub const ZKEY_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/rln_final.zkey");
+const GRAPH_BYTES: &[u8] = include_bytes!("../resources/tree_height_20/graph.bin");
+
+lazy_static! {
+    static ref ZKEY: (ProvingKey<Curve>, ConstraintMatrices<Fr>) = {
+        cfg_if! {
+                if #[cfg(feature = "arkzkey")] {
+                    read_arkzkey_from_bytes_uncompressed(ARKZKEY_BYTES).expect("Failed to read arkzkey")
+                } else {
+                    let mut reader = Cursor::new(ZKEY_BYTES);
+                    read_zkey(&mut reader).expect("Failed to read zkey")
+                }
+        }
+    };
 }
 
-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 20 & 32
-// Changing these parameters to other values than these defaults will cause zkSNARK proof verification to fail
-pub const TEST_PARAMETERS_INDEX: usize = 0;
-pub const TEST_TREE_HEIGHT: usize = [20, 32][TEST_PARAMETERS_INDEX];
-pub const TEST_RESOURCES_FOLDER: &str = ["tree_height_20", "tree_height_32"][TEST_PARAMETERS_INDEX];
-
-#[cfg(not(target_arch = "wasm32"))]
-static RESOURCES_DIR: Dir<'_> = include_dir!("$CARGO_MANIFEST_DIR/resources");
+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
@@ -51,217 +60,179 @@ 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!"))
+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(
-    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!"))
-    }
+pub fn zkey_from_folder() -> &'static (ProvingKey<Curve>, ConstraintMatrices<Fr>) {
+    &ZKEY
 }
 
 // Loads the verification key from a bytes vector
-pub fn vk_from_raw(vk_data: &[u8], zkey_data: &Vec<u8>) -> Result<VerifyingKey<Curve>> {
-    let verifying_key: VerifyingKey<Curve>;
-
-    if !vk_data.is_empty() {
-        verifying_key = vk_from_vector(vk_data)?;
-        Ok(verifying_key)
-    } else if !zkey_data.is_empty() {
+pub fn vk_from_raw(zkey_data: &[u8]) -> Result<VerifyingKey<Curve>> {
+    if !zkey_data.is_empty() {
         let (proving_key, _matrices) = zkey_from_raw(zkey_data)?;
-        verifying_key = proving_key.vk;
-        Ok(verifying_key)
-    } else {
-        Err(Report::msg("No proving/verification key found!"))
-    }
-}
-
-// Loads the verification key
-#[cfg(not(target_arch = "wasm32"))]
-pub fn vk_from_folder(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::from(BigUint::from_str(s)?))
-}
-
-// Extracts the element in G1 corresponding to its JSON serialization
-fn json_to_g1(json: &Value, key: &str) -> Result<G1Affine> {
-    let els: Vec<String> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| i.as_str().ok_or(Report::msg("element is not a string")))
-        .map(|x| x.map(|v| v.to_owned()))
-        .collect::<Result<Vec<String>>>()?;
-
-    Ok(G1Affine::from(G1Projective::new(
-        fq_from_str(&els[0])?,
-        fq_from_str(&els[1])?,
-        fq_from_str(&els[2])?,
-    )))
-}
-
-// Extracts the vector of G1 elements corresponding to its JSON serialization
-fn json_to_g1_vec(json: &Value, key: &str) -> Result<Vec<G1Affine>> {
-    let els: Vec<Vec<String>> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| {
-            i.as_array()
-                .ok_or(Report::msg("element is not an array"))
-                .and_then(|array| {
-                    array
-                        .iter()
-                        .map(|x| x.as_str().ok_or(Report::msg("element is not a string")))
-                        .map(|x| x.map(|v| v.to_owned()))
-                        .collect::<Result<Vec<String>>>()
-                })
-        })
-        .collect::<Result<Vec<Vec<String>>>>()?;
-
-    let mut res = vec![];
-    for coords in els {
-        res.push(G1Affine::from(G1Projective::new(
-            fq_from_str(&coords[0])?,
-            fq_from_str(&coords[1])?,
-            fq_from_str(&coords[2])?,
-        )))
+        return Ok(proving_key.vk);
     }
 
-    Ok(res)
-}
-
-// Extracts the element in G2 corresponding to its JSON serialization
-fn json_to_g2(json: &Value, key: &str) -> Result<G2Affine> {
-    let els: Vec<Vec<String>> = json
-        .get(key)
-        .ok_or(Report::msg("no json value"))?
-        .as_array()
-        .ok_or(Report::msg("value not an array"))?
-        .iter()
-        .map(|i| {
-            i.as_array()
-                .ok_or(Report::msg("element is not an array"))
-                .and_then(|array| {
-                    array
-                        .iter()
-                        .map(|x| x.as_str().ok_or(Report::msg("element is not a string")))
-                        .map(|x| x.map(|v| v.to_owned()))
-                        .collect::<Result<Vec<String>>>()
-                })
-        })
-        .collect::<Result<Vec<Vec<String>>>>()?;
-
-    let x = Fq2::new(fq_from_str(&els[0][0])?, fq_from_str(&els[0][1])?);
-    let y = Fq2::new(fq_from_str(&els[1][0])?, fq_from_str(&els[1][1])?);
-    let z = Fq2::new(fq_from_str(&els[2][0])?, fq_from_str(&els[2][1])?);
-    Ok(G2Affine::from(G2Projective::new(x, y, z)))
-}
-
-// Converts JSON to a VerifyingKey
-fn to_verifying_key(json: serde_json::Value) -> Result<VerifyingKey<Curve>> {
-    Ok(VerifyingKey {
-        alpha_g1: json_to_g1(&json, "vk_alpha_1")?,
-        beta_g2: json_to_g2(&json, "vk_beta_2")?,
-        gamma_g2: json_to_g2(&json, "vk_gamma_2")?,
-        delta_g2: json_to_g2(&json, "vk_delta_2")?,
-        gamma_abc_g1: json_to_g1_vec(&json, "IC")?,
-    })
-}
-
-// Computes the verification key from its JSON serialization
-fn vk_from_json(vk: &str) -> Result<VerifyingKey<Curve>> {
-    let json: Value = serde_json::from_str(vk)?;
-    to_verifying_key(json)
-}
-
-// Computes the verification key from a bytes vector containing its JSON serialization
-fn vk_from_vector(vk: &[u8]) -> Result<VerifyingKey<Curve>> {
-    let json = String::from_utf8(vk.to_vec())?;
-    let json: Value = serde_json::from_str(&json)?;
-
-    to_verifying_key(json)
+    Err(Report::msg("No proving/verification key found!"))
 }
 
 // Checks verification key to be correct with respect to proving key
-#[cfg(not(target_arch = "wasm32"))]
-pub fn check_vk_from_zkey(
-    resources_folder: &str,
-    verifying_key: VerifyingKey<Curve>,
-) -> Result<()> {
-    let (proving_key, _matrices) = zkey_from_folder(resources_folder)?;
+pub fn check_vk_from_zkey(verifying_key: VerifyingKey<Curve>) -> Result<()> {
+    let (proving_key, _matrices) = zkey_from_folder();
     if proving_key.vk == verifying_key {
         Ok(())
     } else {
         Err(Report::msg("verifying_keys are not equal"))
     }
 }
+
+pub fn calculate_rln_witness<I: IntoIterator<Item = (String, Vec<Fr>)>>(
+    inputs: I,
+    graph_data: &[u8],
+) -> Vec<Fr> {
+    // calc_witness(inputs, graph_data)
+    let res = calc_witness_2(inputs, graph_data).unwrap();
+    res.iter().map(|v| u256_to_fr(&v)).collect()
+}
+
+pub fn calc_witness_2<I: IntoIterator<Item = (String, Vec<Fr>)>>(inputs: I, graph_data: &[u8]) -> std::result::Result<Vec<U256>, Error> {
+
+    // HashMap<String, U256>
+    // let inputs = deserialize_inputs(inputs.as_bytes())?;
+
+    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);
+
+    Ok(graph::evaluate(&nodes, inputs_buffer.as_slice(), &signals))
+}
+
+fn get_inputs_buffer(size: usize) -> Vec<U256> {
+    let mut inputs = vec![U256::ZERO; size];
+    inputs[0] = U256::from(1);
+    inputs
+}
+
+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);
+        }
+        // println!("input {}, offset {}, len {}", key, offset, len);
+
+        for (i, v) in value.iter().enumerate() {
+            input_buffer[offset + i] = *v;
+        }
+    }
+}
+
+pub fn graph_from_folder() -> &'static [u8] {
+    GRAPH_BYTES
+}
+
+////////////////////////////////////////////////////////
+// Functions and structs from [arkz-key](https://github.com/zkmopro/ark-zkey/blob/main/src/lib.rs#L106)
+// without print and allow to choose between compressed and uncompressed arkzkey
+////////////////////////////////////////////////////////
+
+#[cfg(feature = "arkzkey")]
+#[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
+pub struct SerializableProvingKey(pub ProvingKey<Bn254>);
+
+#[cfg(feature = "arkzkey")]
+#[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
+pub struct SerializableConstraintMatrices<F: Field> {
+    pub num_instance_variables: usize,
+    pub num_witness_variables: usize,
+    pub num_constraints: usize,
+    pub a_num_non_zero: usize,
+    pub b_num_non_zero: usize,
+    pub c_num_non_zero: usize,
+    pub a: SerializableMatrix<F>,
+    pub b: SerializableMatrix<F>,
+    pub c: SerializableMatrix<F>,
+}
+
+#[cfg(feature = "arkzkey")]
+#[derive(CanonicalSerialize, CanonicalDeserialize, Clone, Debug, PartialEq)]
+pub struct SerializableMatrix<F: Field> {
+    pub data: Vec<Vec<(F, usize)>>,
+}
+
+#[cfg(feature = "arkzkey")]
+pub fn read_arkzkey_from_bytes_uncompressed(
+    arkzkey_data: &[u8],
+) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
+    if arkzkey_data.is_empty() {
+        return Err(Report::msg("No proving key found!"));
+    }
+
+    let mut cursor = std::io::Cursor::new(arkzkey_data);
+
+    let serialized_proving_key =
+        SerializableProvingKey::deserialize_uncompressed_unchecked(&mut cursor)
+            .wrap_err("Failed to deserialize proving key")?;
+
+    let serialized_constraint_matrices =
+        SerializableConstraintMatrices::deserialize_uncompressed_unchecked(&mut cursor)
+            .wrap_err("Failed to deserialize constraint matrices")?;
+
+    // Get on right form for API
+    let proving_key: ProvingKey<Bn254> = serialized_proving_key.0;
+    let constraint_matrices: ConstraintMatrices<ark_bn254::Fr> = ConstraintMatrices {
+        num_instance_variables: serialized_constraint_matrices.num_instance_variables,
+        num_witness_variables: serialized_constraint_matrices.num_witness_variables,
+        num_constraints: serialized_constraint_matrices.num_constraints,
+        a_num_non_zero: serialized_constraint_matrices.a_num_non_zero,
+        b_num_non_zero: serialized_constraint_matrices.b_num_non_zero,
+        c_num_non_zero: serialized_constraint_matrices.c_num_non_zero,
+        a: serialized_constraint_matrices.a.data,
+        b: serialized_constraint_matrices.b.data,
+        c: serialized_constraint_matrices.c.data,
+    };
+
+    Ok((proving_key, constraint_matrices))
+}

rln/src/ffi.rs

@@ -8,6 +8,7 @@ use crate::public::{hash as public_hash, poseidon_hash as public_poseidon_hash,
 // First argument to the macro is context,
 // second is the actual method on `RLN`
 // rest are all other arguments to the method
+#[cfg(not(feature = "stateless"))]
 macro_rules! call {
     ($instance:expr, $method:ident $(, $arg:expr)*) => {
         {
@@ -143,24 +144,24 @@ impl ProcessArg for *const Buffer {
     }
 }
 
-impl<'a> ProcessArg for *const RLN<'a> {
-    type ReturnType = &'a RLN<'a>;
+impl ProcessArg for *const RLN {
+    type ReturnType = &'static RLN;
     fn process(self) -> Self::ReturnType {
         unsafe { &*self }
     }
 }
 
-impl<'a> ProcessArg for *mut RLN<'a> {
-    type ReturnType = &'a mut RLN<'a>;
+impl ProcessArg for *mut RLN {
+    type ReturnType = &'static mut RLN;
     fn process(self) -> Self::ReturnType {
         unsafe { &mut *self }
     }
 }
 
-/// Buffer struct is taken from
-/// <https://github.com/celo-org/celo-threshold-bls-rs/blob/master/crates/threshold-bls-ffi/src/ffi.rs>
-///
-/// Also heavily inspired by <https://github.com/kilic/rln/blob/master/src/ffi.rs>
+///// Buffer struct is taken from
+///// <https://github.com/celo-org/celo-threshold-bls-rs/blob/master/crates/threshold-bls-ffi/src/ffi.rs>
+/////
+///// Also heavily inspired by <https://github.com/kilic/rln/blob/master/src/ffi.rs>
 
 #[repr(C)]
 #[derive(Clone, Debug, PartialEq)]
@@ -192,6 +193,7 @@ impl<'a> From<&Buffer> for &'a [u8] {
 ////////////////////////////////////////////////////////
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(not(feature = "stateless"))]
 #[no_mangle]
 pub extern "C" fn new(tree_height: usize, input_buffer: *const Buffer, ctx: *mut *mut RLN) -> bool {
     match RLN::new(tree_height, input_buffer.process()) {
@@ -207,20 +209,35 @@ pub extern "C" fn new(tree_height: usize, input_buffer: *const Buffer, ctx: *mut
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(feature = "stateless")]
+#[no_mangle]
+pub extern "C" fn new(ctx: *mut *mut RLN) -> bool {
+    match RLN::new() {
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
+    }
+}
+
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(not(feature = "stateless"))]
 #[no_mangle]
 pub extern "C" fn new_with_params(
     tree_height: usize,
-    circom_buffer: *const Buffer,
     zkey_buffer: *const Buffer,
-    vk_buffer: *const Buffer,
+    graph_data: *const Buffer,
     tree_config: *const Buffer,
     ctx: *mut *mut RLN,
 ) -> bool {
     match RLN::new_with_params(
         tree_height,
-        circom_buffer.process().to_vec(),
         zkey_buffer.process().to_vec(),
-        vk_buffer.process().to_vec(),
+        graph_data.process().to_vec(),
         tree_config.process(),
     ) {
         Ok(rln) => {
@@ -234,47 +251,77 @@ pub extern "C" fn new_with_params(
     }
 }
 
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[cfg(feature = "stateless")]
+#[no_mangle]
+pub extern "C" fn new_with_params(
+    zkey_buffer: *const Buffer,
+    graph_buffer: *const Buffer,
+    ctx: *mut *mut RLN,
+) -> bool {
+    match RLN::new_with_params(
+        zkey_buffer.process().to_vec(),
+        graph_buffer.process().to_vec(),
+    ) {
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
+    }
+}
+
 ////////////////////////////////////////////////////////
 // Merkle tree APIs
 ////////////////////////////////////////////////////////
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_tree(ctx: *mut RLN, tree_height: usize) -> bool {
     call!(ctx, set_tree, tree_height)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn delete_leaf(ctx: *mut RLN, index: usize) -> bool {
     call!(ctx, delete_leaf, index)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_leaf(ctx: *mut RLN, index: usize, input_buffer: *const Buffer) -> bool {
     call!(ctx, set_leaf, index, input_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_leaf(ctx: *mut RLN, index: usize, output_buffer: *mut Buffer) -> bool {
     call_with_output_arg!(ctx, get_leaf, output_buffer, index)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn leaves_set(ctx: *mut RLN) -> usize {
     ctx.process().leaves_set()
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_next_leaf(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
     call!(ctx, set_next_leaf, input_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_leaves_from(
     ctx: *mut RLN,
     index: usize,
@@ -285,12 +332,14 @@ pub extern "C" fn set_leaves_from(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn init_tree_with_leaves(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
     call!(ctx, init_tree_with_leaves, input_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn atomic_operation(
     ctx: *mut RLN,
     index: usize,
@@ -302,6 +351,7 @@ pub extern "C" fn atomic_operation(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn seq_atomic_operation(
     ctx: *mut RLN,
     leaves_buffer: *const Buffer,
@@ -318,12 +368,14 @@ pub extern "C" fn seq_atomic_operation(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_root(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
     call_with_output_arg!(ctx, get_root, output_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_proof(ctx: *const RLN, index: usize, output_buffer: *mut Buffer) -> bool {
     call_with_output_arg!(ctx, get_proof, output_buffer, index)
 }
@@ -353,6 +405,7 @@ pub extern "C" fn verify(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn generate_rln_proof(
     ctx: *mut RLN,
     input_buffer: *const Buffer,
@@ -363,6 +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,
@@ -446,18 +515,21 @@ pub extern "C" fn recover_id_secret(
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn set_metadata(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
     call!(ctx, set_metadata, input_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn get_metadata(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {
     call_with_output_arg!(ctx, get_metadata, output_buffer)
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
+#[cfg(not(feature = "stateless"))]
 pub extern "C" fn flush(ctx: *mut RLN) -> bool {
     call!(ctx, flush)
 }

rln/src/iden3calc.rs

@@ -0,0 +1,73 @@
+// This file is based on the code by iden3. Its preimage can be found here:
+// https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/src/lib.rs
+
+pub mod graph;
+pub mod proto;
+pub mod storage;
+
+use ruint::aliases::U256;
+use std::collections::HashMap;
+use storage::deserialize_witnesscalc_graph;
+
+use crate::circuit::Fr;
+use graph::{fr_to_u256, Node};
+
+pub type InputSignalsInfo = HashMap<String, (usize, usize)>;
+
+pub fn calc_witness<I: IntoIterator<Item = (String, Vec<Fr>)>>(
+    inputs: I,
+    graph_data: &[u8],
+) -> Vec<Fr> {
+    let inputs: HashMap<String, Vec<U256>> = inputs
+        .into_iter()
+        .map(|(key, value)| (key, value.iter().map(fr_to_u256).collect()))
+        .collect();
+
+    let (nodes, signals, input_mapping): (Vec<Node>, Vec<usize>, InputSignalsInfo) =
+        deserialize_witnesscalc_graph(std::io::Cursor::new(graph_data)).unwrap();
+
+    let mut inputs_buffer = get_inputs_buffer(get_inputs_size(&nodes));
+    populate_inputs(&inputs, &input_mapping, &mut inputs_buffer);
+
+    graph::evaluate(&nodes, inputs_buffer.as_slice(), &signals)
+}
+
+fn get_inputs_size(nodes: &[Node]) -> usize {
+    let mut start = false;
+    let mut max_index = 0usize;
+    for &node in nodes.iter() {
+        if let Node::Input(i) = node {
+            if i > max_index {
+                max_index = i;
+            }
+            start = true
+        } else if start {
+            break;
+        }
+    }
+    max_index + 1
+}
+
+fn populate_inputs(
+    input_list: &HashMap<String, Vec<U256>>,
+    inputs_info: &InputSignalsInfo,
+    input_buffer: &mut [U256],
+) {
+    for (key, value) in input_list {
+        let (offset, len) = inputs_info[key];
+        if len != value.len() {
+            panic!("Invalid input length for {}", key);
+        }
+
+        for (i, v) in value.iter().enumerate() {
+            input_buffer[offset + i] = *v;
+        }
+    }
+}
+
+/// Allocates inputs vec with position 0 set to 1
+fn get_inputs_buffer(size: usize) -> Vec<U256> {
+    let mut inputs = vec![U256::ZERO; size];
+    inputs[0] = U256::from(1);
+    inputs
+}

rln/src/iden3calc/graph.rs

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

rln/src/iden3calc/proto.rs

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

rln/src/iden3calc/storage.rs

@@ -0,0 +1,497 @@
+// This file is based on the code by iden3. Its preimage can be found here:
+// https://github.com/iden3/circom-witnesscalc/blob/5cb365b6e4d9052ecc69d4567fcf5bc061c20e94/src/storage.rs
+
+use ark_bn254::Fr;
+use ark_ff::PrimeField;
+use byteorder::{LittleEndian, ReadBytesExt, WriteBytesExt};
+use prost::Message;
+use std::io::{Read, Write};
+
+use crate::iden3calc::{
+    graph,
+    graph::{Operation, TresOperation, UnoOperation},
+    proto, InputSignalsInfo,
+};
+
+// format of the wtns.graph file:
+// + magic line: wtns.graph.001
+// + 4 bytes unsigned LE 32-bit integer: number of nodes
+// + series of protobuf serialized nodes. Each node prefixed by varint length
+// + protobuf serialized GraphMetadata
+// + 8 bytes unsigned LE 64-bit integer: offset of GraphMetadata message
+
+const WITNESSCALC_GRAPH_MAGIC: &[u8] = b"wtns.graph.001";
+
+const MAX_VARINT_LENGTH: usize = 10;
+
+impl From<proto::Node> for graph::Node {
+    fn from(value: proto::Node) -> Self {
+        match value.node.unwrap() {
+            proto::node::Node::Input(input_node) => graph::Node::Input(input_node.idx as usize),
+            proto::node::Node::Constant(constant_node) => {
+                let i = constant_node.value.unwrap();
+                graph::Node::MontConstant(Fr::from_le_bytes_mod_order(i.value_le.as_slice()))
+            }
+            proto::node::Node::UnoOp(uno_op_node) => {
+                let op = proto::UnoOp::try_from(uno_op_node.op).unwrap();
+                graph::Node::UnoOp(op.into(), uno_op_node.a_idx as usize)
+            }
+            proto::node::Node::DuoOp(duo_op_node) => {
+                let op = proto::DuoOp::try_from(duo_op_node.op).unwrap();
+                graph::Node::Op(
+                    op.into(),
+                    duo_op_node.a_idx as usize,
+                    duo_op_node.b_idx as usize,
+                )
+            }
+            proto::node::Node::TresOp(tres_op_node) => {
+                let op = proto::TresOp::try_from(tres_op_node.op).unwrap();
+                graph::Node::TresOp(
+                    op.into(),
+                    tres_op_node.a_idx as usize,
+                    tres_op_node.b_idx as usize,
+                    tres_op_node.c_idx as usize,
+                )
+            }
+        }
+    }
+}
+
+impl From<&graph::Node> for proto::node::Node {
+    fn from(node: &graph::Node) -> Self {
+        match node {
+            graph::Node::Input(i) => proto::node::Node::Input(proto::InputNode { idx: *i as u32 }),
+            graph::Node::Constant(_) => {
+                panic!("We are not supposed to write Constant to the witnesscalc graph. All Constant should be converted to MontConstant.");
+            }
+            graph::Node::UnoOp(op, a) => {
+                let op = proto::UnoOp::from(op);
+                proto::node::Node::UnoOp(proto::UnoOpNode {
+                    op: op as i32,
+                    a_idx: *a as u32,
+                })
+            }
+            graph::Node::Op(op, a, b) => proto::node::Node::DuoOp(proto::DuoOpNode {
+                op: proto::DuoOp::from(op) as i32,
+                a_idx: *a as u32,
+                b_idx: *b as u32,
+            }),
+            graph::Node::TresOp(op, a, b, c) => proto::node::Node::TresOp(proto::TresOpNode {
+                op: proto::TresOp::from(op) as i32,
+                a_idx: *a as u32,
+                b_idx: *b as u32,
+                c_idx: *c as u32,
+            }),
+            graph::Node::MontConstant(c) => {
+                let bi = Into::<num_bigint::BigUint>::into(*c);
+                let i = proto::BigUInt {
+                    value_le: bi.to_bytes_le(),
+                };
+                proto::node::Node::Constant(proto::ConstantNode { value: Some(i) })
+            }
+        }
+    }
+}
+
+impl From<proto::UnoOp> for UnoOperation {
+    fn from(value: proto::UnoOp) -> Self {
+        match value {
+            proto::UnoOp::Neg => UnoOperation::Neg,
+            proto::UnoOp::Id => UnoOperation::Id,
+        }
+    }
+}
+
+impl From<proto::DuoOp> for Operation {
+    fn from(value: proto::DuoOp) -> Self {
+        match value {
+            proto::DuoOp::Mul => Operation::Mul,
+            proto::DuoOp::Div => Operation::Div,
+            proto::DuoOp::Add => Operation::Add,
+            proto::DuoOp::Sub => Operation::Sub,
+            proto::DuoOp::Pow => Operation::Pow,
+            proto::DuoOp::Idiv => Operation::Idiv,
+            proto::DuoOp::Mod => Operation::Mod,
+            proto::DuoOp::Eq => Operation::Eq,
+            proto::DuoOp::Neq => Operation::Neq,
+            proto::DuoOp::Lt => Operation::Lt,
+            proto::DuoOp::Gt => Operation::Gt,
+            proto::DuoOp::Leq => Operation::Leq,
+            proto::DuoOp::Geq => Operation::Geq,
+            proto::DuoOp::Land => Operation::Land,
+            proto::DuoOp::Lor => Operation::Lor,
+            proto::DuoOp::Shl => Operation::Shl,
+            proto::DuoOp::Shr => Operation::Shr,
+            proto::DuoOp::Bor => Operation::Bor,
+            proto::DuoOp::Band => Operation::Band,
+            proto::DuoOp::Bxor => Operation::Bxor,
+        }
+    }
+}
+
+impl From<proto::TresOp> for graph::TresOperation {
+    fn from(value: proto::TresOp) -> Self {
+        match value {
+            proto::TresOp::TernCond => TresOperation::TernCond,
+        }
+    }
+}
+
+pub fn serialize_witnesscalc_graph<T: Write>(
+    mut w: T,
+    nodes: &Vec<graph::Node>,
+    witness_signals: &[usize],
+    input_signals: &InputSignalsInfo,
+) -> std::io::Result<()> {
+    let mut ptr = 0usize;
+    w.write_all(WITNESSCALC_GRAPH_MAGIC).unwrap();
+    ptr += WITNESSCALC_GRAPH_MAGIC.len();
+
+    w.write_u64::<LittleEndian>(nodes.len() as u64)?;
+    ptr += 8;
+
+    let metadata = proto::GraphMetadata {
+        witness_signals: witness_signals
+            .iter()
+            .map(|x| *x as u32)
+            .collect::<Vec<u32>>(),
+        inputs: input_signals
+            .iter()
+            .map(|(k, v)| {
+                let sig = proto::SignalDescription {
+                    offset: v.0 as u32,
+                    len: v.1 as u32,
+                };
+                (k.clone(), sig)
+            })
+            .collect(),
+    };
+
+    // capacity of buf should be enough to hold the largest message + 10 bytes
+    // of varint length
+    let mut buf = Vec::with_capacity(metadata.encoded_len() + MAX_VARINT_LENGTH);
+
+    for node in nodes {
+        let node_pb = proto::Node {
+            node: Some(proto::node::Node::from(node)),
+        };
+
+        assert_eq!(buf.len(), 0);
+        node_pb.encode_length_delimited(&mut buf)?;
+        ptr += buf.len();
+
+        w.write_all(&buf)?;
+        buf.clear();
+    }
+
+    metadata.encode_length_delimited(&mut buf)?;
+    w.write_all(&buf)?;
+    buf.clear();
+
+    w.write_u64::<LittleEndian>(ptr as u64)?;
+
+    Ok(())
+}
+
+fn read_message_length<R: Read>(rw: &mut WriteBackReader<R>) -> std::io::Result<usize> {
+    let mut buf = [0u8; MAX_VARINT_LENGTH];
+    let bytes_read = rw.read(&mut buf)?;
+    if bytes_read == 0 {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::UnexpectedEof,
+            "Unexpected EOF",
+        ));
+    }
+
+    let len_delimiter = prost::decode_length_delimiter(buf.as_ref())?;
+
+    let lnln = prost::length_delimiter_len(len_delimiter);
+
+    if lnln < bytes_read {
+        rw.write_all(&buf[lnln..bytes_read])?;
+    }
+
+    Ok(len_delimiter)
+}
+
+fn read_message<R: Read, M: Message + std::default::Default>(
+    rw: &mut WriteBackReader<R>,
+) -> std::io::Result<M> {
+    let ln = read_message_length(rw)?;
+    let mut buf = vec![0u8; ln];
+    let bytes_read = rw.read(&mut buf)?;
+    if bytes_read != ln {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::UnexpectedEof,
+            "Unexpected EOF",
+        ));
+    }
+
+    let msg = prost::Message::decode(&buf[..])?;
+
+    Ok(msg)
+}
+
+pub fn deserialize_witnesscalc_graph(
+    r: impl Read,
+) -> std::io::Result<(Vec<graph::Node>, Vec<usize>, InputSignalsInfo)> {
+    let mut br = WriteBackReader::new(r);
+    let mut magic = [0u8; WITNESSCALC_GRAPH_MAGIC.len()];
+
+    br.read_exact(&mut magic)?;
+
+    if !magic.eq(WITNESSCALC_GRAPH_MAGIC) {
+        return Err(std::io::Error::new(
+            std::io::ErrorKind::InvalidData,
+            "Invalid magic",
+        ));
+    }
+
+    let nodes_num = br.read_u64::<LittleEndian>()?;
+    let mut nodes = Vec::with_capacity(nodes_num as usize);
+    for _ in 0..nodes_num {
+        let n: proto::Node = read_message(&mut br)?;
+        let n2: graph::Node = n.into();
+        nodes.push(n2);
+    }
+
+    let md: proto::GraphMetadata = read_message(&mut br)?;
+
+    let witness_signals = md
+        .witness_signals
+        .iter()
+        .map(|x| *x as usize)
+        .collect::<Vec<usize>>();
+
+    let input_signals = md
+        .inputs
+        .iter()
+        .map(|(k, v)| (k.clone(), (v.offset as usize, v.len as usize)))
+        .collect::<InputSignalsInfo>();
+
+    Ok((nodes, witness_signals, input_signals))
+}
+
+struct WriteBackReader<R: Read> {
+    reader: R,
+    buffer: Vec<u8>,
+}
+
+impl<R: Read> WriteBackReader<R> {
+    fn new(reader: R) -> Self {
+        WriteBackReader {
+            reader,
+            buffer: Vec::new(),
+        }
+    }
+}
+
+impl<R: Read> Read for WriteBackReader<R> {
+    fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
+        if buf.is_empty() {
+            return Ok(0);
+        }
+
+        let mut n = 0usize;
+
+        if !self.buffer.is_empty() {
+            n = std::cmp::min(buf.len(), self.buffer.len());
+            self.buffer[self.buffer.len() - n..]
+                .iter()
+                .rev()
+                .enumerate()
+                .for_each(|(i, x)| {
+                    buf[i] = *x;
+                });
+            self.buffer.truncate(self.buffer.len() - n);
+        }
+
+        while n < buf.len() {
+            let m = self.reader.read(&mut buf[n..])?;
+            if m == 0 {
+                break;
+            }
+            n += m;
+        }
+
+        Ok(n)
+    }
+}
+
+impl<R: Read> Write for WriteBackReader<R> {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        self.buffer.reserve(buf.len());
+        self.buffer.extend(buf.iter().rev());
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use byteorder::ByteOrder;
+    use core::str::FromStr;
+    use graph::{Operation, TresOperation, UnoOperation};
+    use std::collections::HashMap;
+
+    #[test]
+    fn test_read_message() {
+        let mut buf = Vec::new();
+        let n1 = proto::Node {
+            node: Some(proto::node::Node::Input(proto::InputNode { idx: 1 })),
+        };
+        n1.encode_length_delimited(&mut buf).unwrap();
+
+        let n2 = proto::Node {
+            node: Some(proto::node::Node::Input(proto::InputNode { idx: 2 })),
+        };
+        n2.encode_length_delimited(&mut buf).unwrap();
+
+        let mut reader = std::io::Cursor::new(&buf);
+
+        let mut rw = WriteBackReader::new(&mut reader);
+
+        let got_n1: proto::Node = read_message(&mut rw).unwrap();
+        assert!(n1.eq(&got_n1));
+
+        let got_n2: proto::Node = read_message(&mut rw).unwrap();
+        assert!(n2.eq(&got_n2));
+
+        assert_eq!(reader.position(), buf.len() as u64);
+    }
+
+    #[test]
+    fn test_read_message_variant() {
+        let nodes = vec![
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::Input(0))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::MontConstant(
+                    Fr::from_str("1").unwrap(),
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::UnoOp(
+                    UnoOperation::Id,
+                    4,
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::Op(
+                    Operation::Mul,
+                    5,
+                    6,
+                ))),
+            },
+            proto::Node {
+                node: Some(proto::node::Node::from(&graph::Node::TresOp(
+                    TresOperation::TernCond,
+                    7,
+                    8,
+                    9,
+                ))),
+            },
+        ];
+
+        let mut buf = Vec::new();
+        for n in &nodes {
+            n.encode_length_delimited(&mut buf).unwrap();
+        }
+
+        let mut nodes_got: Vec<proto::Node> = Vec::new();
+        let mut reader = std::io::Cursor::new(&buf);
+        let mut rw = WriteBackReader::new(&mut reader);
+        for _ in 0..nodes.len() {
+            nodes_got.push(read_message(&mut rw).unwrap());
+        }
+
+        assert_eq!(nodes, nodes_got);
+    }
+
+    #[test]
+    fn test_write_back_reader() {
+        let data = [1u8, 2, 3, 4, 5, 6];
+        let mut r = WriteBackReader::new(std::io::Cursor::new(&data));
+
+        let buf = &mut [0u8; 5];
+        r.read(buf).unwrap();
+        assert_eq!(buf, &[1, 2, 3, 4, 5]);
+
+        // return [4, 5] to reader
+        r.write(&buf[3..]).unwrap();
+        // return [2, 3] to reader
+        r.write(&buf[1..3]).unwrap();
+
+        buf.fill(0);
+
+        // read 3 bytes, expect [2, 3, 4] after returns
+        let mut n = r.read(&mut buf[..3]).unwrap();
+        assert_eq!(n, 3);
+        assert_eq!(buf, &[2, 3, 4, 0, 0]);
+
+        buf.fill(0);
+
+        // read everything left in reader
+        n = r.read(buf).unwrap();
+        assert_eq!(n, 2);
+        assert_eq!(buf, &[5, 6, 0, 0, 0]);
+    }
+
+    #[test]
+    fn test_deserialize_inputs() {
+        let nodes = vec![
+            graph::Node::Input(0),
+            graph::Node::MontConstant(Fr::from_str("1").unwrap()),
+            graph::Node::UnoOp(UnoOperation::Id, 4),
+            graph::Node::Op(Operation::Mul, 5, 6),
+            graph::Node::TresOp(TresOperation::TernCond, 7, 8, 9),
+        ];
+
+        let witness_signals = vec![4, 1];
+
+        let mut input_signals: InputSignalsInfo = HashMap::new();
+        input_signals.insert("sig1".to_string(), (1, 3));
+        input_signals.insert("sig2".to_string(), (5, 1));
+
+        let mut tmp = Vec::new();
+        serialize_witnesscalc_graph(&mut tmp, &nodes, &witness_signals, &input_signals).unwrap();
+
+        let mut reader = std::io::Cursor::new(&tmp);
+
+        let (nodes_res, witness_signals_res, input_signals_res) =
+            deserialize_witnesscalc_graph(&mut reader).unwrap();
+
+        assert_eq!(nodes, nodes_res);
+        assert_eq!(input_signals, input_signals_res);
+        assert_eq!(witness_signals, witness_signals_res);
+
+        let metadata_start = LittleEndian::read_u64(&tmp[tmp.len() - 8..]);
+
+        let mt_reader = std::io::Cursor::new(&tmp[metadata_start as usize..]);
+        let mut rw = WriteBackReader::new(mt_reader);
+        let metadata: proto::GraphMetadata = read_message(&mut rw).unwrap();
+
+        let metadata_want = proto::GraphMetadata {
+            witness_signals: vec![4, 1],
+            inputs: input_signals
+                .iter()
+                .map(|(k, v)| {
+                    (
+                        k.clone(),
+                        proto::SignalDescription {
+                            offset: v.0 as u32,
+                            len: v.1 as u32,
+                        },
+                    )
+                })
+                .collect(),
+        };
+
+        assert_eq!(metadata, metadata_want);
+    }
+}

rln/src/lib.rs

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

rln/src/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,
@@ -201,7 +244,7 @@ impl ZerokitMerkleTree for PmTree {
             (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_with_leaves(start, leaves),
+            (_, 0) => self.set_range(start, leaves),
             (0, _) => self.remove_indices(&indices),
             (_, _) => self.remove_indices_and_set_leaves(start, leaves, &indices),
         }
@@ -216,7 +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> {
@@ -261,12 +306,6 @@ 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: &[usize]) -> Result<()> {
         let start = indices[0];
         let end = indices.last().unwrap() + 1;
@@ -275,7 +314,12 @@ impl PmTree {
 
         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(
@@ -301,8 +345,17 @@ impl PmTree {
         }
 
         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(())
     }
 }
 

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_circom::CircomReduction;
 use ark_groth16::{prepare_verifying_key, Groth16, Proof as ArkProof, ProvingKey, VerifyingKey};
-use ark_relations::r1cs::ConstraintMatrices;
-use ark_relations::r1cs::SynthesisError;
+use ark_relations::r1cs::{ConstraintMatrices, SynthesisError};
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
 use ark_std::{rand::thread_rng, UniformRand};
 use color_eyre::{Report, Result};
 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, 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,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
     external_nullifier: Fr,
 }
 
@@ -95,18 +99,26 @@ pub fn deserialize_identity_tuple(serialized: Vec<u8>) -> (Fr, Fr, Fr, Fr) {
 /// # Errors
 ///
 /// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
+/// input data is [ identity_secret<32> | user_message_limit<32> | message_id<32> | path_elements[<32>] | identity_path_index<8> | x<32> | external_nullifier<32> ]
 pub fn serialize_witness(rln_witness: &RLNWitnessInput) -> Result<Vec<u8>> {
+    // Check if message_id is within user_message_limit
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
 
-    let mut serialized: Vec<u8> = Vec::new();
-
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.identity_secret));
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.user_message_limit));
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.message_id));
-    serialized.append(&mut vec_fr_to_bytes_le(&rln_witness.path_elements)?);
-    serialized.append(&mut vec_u8_to_bytes_le(&rln_witness.identity_path_index)?);
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.x));
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.external_nullifier));
+    // Calculate capacity for Vec:
+    // - 5 fixed field elements: identity_secret, user_message_limit, message_id, x, external_nullifier
+    // - variable number of path elements
+    // - identity_path_index (variable size)
+    let mut serialized: Vec<u8> = Vec::with_capacity(
+        fr_byte_size() * (5 + rln_witness.path_elements.len())
+            + rln_witness.identity_path_index.len(),
+    );
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.identity_secret));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.user_message_limit));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.message_id));
+    serialized.extend_from_slice(&vec_fr_to_bytes_le(&rln_witness.path_elements)?);
+    serialized.extend_from_slice(&vec_u8_to_bytes_le(&rln_witness.identity_path_index)?);
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.x));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_witness.external_nullifier));
 
     Ok(serialized)
 }
@@ -162,7 +174,7 @@ 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> | user_message_limit<32> | message_id<32> | signal_len<8> | signal<var> ]
+// input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
 // return value is a rln witness populated according to this information
 pub fn proof_inputs_to_rln_witness(
     tree: &mut PoseidonTree,
@@ -214,56 +226,7 @@ pub fn proof_inputs_to_rln_witness(
     ))
 }
 
-/// Returns `RLNWitnessInput` given a file with JSON serialized values.
-///
-/// # Errors
-///
-/// Returns an error if `message_id` is not within `user_message_limit`.
-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");
-
-    let user_message_limit = str_to_fr(&input_json["userMessageLimit"].to_string(), 10)?;
-
-    let message_id = str_to_fr(&input_json["messageId"].to_string(), 10)?;
-
-    message_id_range_check(&message_id, &user_message_limit)?;
-
-    let identity_secret = str_to_fr(&input_json["identitySecret"].to_string(), 10)?;
-
-    let path_elements = input_json["pathElements"]
-        .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["identityPathIndex"]
-        .as_array()
-        .ok_or(Report::msg("not an array"))?;
-
-    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 external_nullifier = str_to_fr(&input_json["externalNullifier"].to_string(), 10)?;
-
-    Ok(RLNWitnessInput {
-        identity_secret,
-        path_elements,
-        identity_path_index,
-        x,
-        external_nullifier,
-        user_message_limit,
-        message_id,
-    })
-}
-
-/// Creates `RLNWitnessInput` from it's fields.
+/// Creates [`RLNWitnessInput`] from it's fields.
 ///
 /// # Errors
 ///
@@ -350,14 +313,17 @@ pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> Result<RLNPro
     })
 }
 
+/// input_data is [ root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
 pub fn serialize_proof_values(rln_proof_values: &RLNProofValues) -> Vec<u8> {
-    let mut serialized: Vec<u8> = Vec::new();
+    // Calculate capacity for Vec:
+    // 5 field elements: root, external_nullifier, x, y, nullifier
+    let mut serialized = Vec::with_capacity(fr_byte_size() * 5);
 
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.root));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.external_nullifier));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.x));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.y));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.nullifier));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.root));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.external_nullifier));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.x));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.y));
+    serialized.extend_from_slice(&fr_to_bytes_le(&rln_proof_values.nullifier));
 
     serialized
 }
@@ -394,30 +360,43 @@ pub fn deserialize_proof_values(serialized: &[u8]) -> (RLNProofValues, usize) {
     )
 }
 
+// input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
 pub fn prepare_prove_input(
     identity_secret: Fr,
     id_index: usize,
+    user_message_limit: Fr,
+    message_id: Fr,
     external_nullifier: Fr,
     signal: &[u8],
 ) -> Vec<u8> {
-    let mut serialized: Vec<u8> = Vec::new();
+    // Calculate capacity for Vec:
+    // - 4 field elements: identity_secret, user_message_limit, message_id, external_nullifier
+    // - 16 bytes for two normalized usize values (id_index<8> + signal_len<8>)
+    // - variable length signal data
+    let mut serialized = Vec::with_capacity(fr_byte_size() * 4 + 16 + signal.len()); // length of 4 fr elements + 16 bytes (id_index + len) + signal length
 
-    serialized.append(&mut fr_to_bytes_le(&identity_secret));
-    serialized.append(&mut normalize_usize(id_index));
-    serialized.append(&mut fr_to_bytes_le(&external_nullifier));
-    serialized.append(&mut normalize_usize(signal.len()));
-    serialized.append(&mut signal.to_vec());
+    serialized.extend_from_slice(&fr_to_bytes_le(&identity_secret));
+    serialized.extend_from_slice(&normalize_usize(id_index));
+    serialized.extend_from_slice(&fr_to_bytes_le(&user_message_limit));
+    serialized.extend_from_slice(&fr_to_bytes_le(&message_id));
+    serialized.extend_from_slice(&fr_to_bytes_le(&external_nullifier));
+    serialized.extend_from_slice(&normalize_usize(signal.len()));
+    serialized.extend_from_slice(signal);
 
     serialized
 }
 
-#[allow(clippy::redundant_clone)]
+// input_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
 pub fn prepare_verify_input(proof_data: Vec<u8>, signal: &[u8]) -> Vec<u8> {
-    let mut serialized: Vec<u8> = Vec::new();
+    // Calculate capacity for Vec:
+    // - proof_data contains the proof and proof values (proof<128> + root<32> + external_nullifier<32> + x<32> + y<32> + nullifier<32>)
+    // - 8 bytes for normalized signal length value (signal_len<8>)
+    // - variable length signal data
+    let mut serialized = Vec::with_capacity(proof_data.len() + 8 + signal.len());
 
-    serialized.append(&mut proof_data.clone());
-    serialized.append(&mut normalize_usize(signal.len()));
-    serialized.append(&mut signal.to_vec());
+    serialized.extend(proof_data);
+    serialized.extend_from_slice(&normalize_usize(signal.len()));
+    serialized.extend_from_slice(signal);
 
     serialized
 }
@@ -585,13 +564,13 @@ pub fn generate_proof_with_witness(
     proving_key: &(ProvingKey<Curve>, ConstraintMatrices<Fr>),
 ) -> Result<ArkProof<Curve>, ProofError> {
     // If in debug mode, we measure and later print time take to compute witness
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
 
     let full_assignment =
         calculate_witness_element::<Curve>(witness).map_err(ProofError::WitnessError)?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("witness generation took: {:.2?}", now.elapsed());
 
     // Random Values
@@ -600,7 +579,7 @@ pub fn generate_proof_with_witness(
     let s = Fr::rand(&mut rng);
 
     // If in debug mode, we measure and later print time take to compute proof
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
 
     let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
@@ -613,7 +592,7 @@ pub fn generate_proof_with_witness(
         full_assignment.as_slice(),
     )?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("proof generation took: {:.2?}", now.elapsed());
 
     Ok(proof)
@@ -626,40 +605,23 @@ pub fn generate_proof_with_witness(
 /// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
 pub fn inputs_for_witness_calculation(
     rln_witness: &RLNWitnessInput,
-) -> Result<[(&str, Vec<BigInt>); 7]> {
+) -> Result<[(&str, Vec<Fr>); 7]> {
     message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
 
-    // We convert the path indexes to field elements
-    // TODO: check if necessary
-    let mut path_elements = Vec::new();
-
-    for v in rln_witness.path_elements.iter() {
-        path_elements.push(to_bigint(v)?);
-    }
-
-    let mut identity_path_index = Vec::new();
+    let mut identity_path_index = Vec::with_capacity(rln_witness.identity_path_index.len());
     rln_witness
         .identity_path_index
         .iter()
-        .for_each(|v| identity_path_index.push(BigInt::from(*v)));
+        .for_each(|v| identity_path_index.push(Fr::from(*v)));
 
     Ok([
-        (
-            "identitySecret",
-            vec![to_bigint(&rln_witness.identity_secret)?],
-        ),
-        (
-            "userMessageLimit",
-            vec![to_bigint(&rln_witness.user_message_limit)?],
-        ),
-        ("messageId", vec![to_bigint(&rln_witness.message_id)?]),
-        ("pathElements", path_elements),
+        ("identitySecret", vec![rln_witness.identity_secret]),
+        ("userMessageLimit", vec![rln_witness.user_message_limit]),
+        ("messageId", vec![rln_witness.message_id]),
+        ("pathElements", rln_witness.path_elements.clone()),
         ("identityPathIndex", identity_path_index),
-        ("x", vec![to_bigint(&rln_witness.x)?]),
-        (
-            "externalNullifier",
-            vec![to_bigint(&rln_witness.external_nullifier)?],
-        ),
+        ("x", vec![rln_witness.x]),
+        ("externalNullifier", vec![rln_witness.external_nullifier]),
     ])
 }
 
@@ -669,34 +631,20 @@ pub fn inputs_for_witness_calculation(
 ///
 /// Returns a [`ProofError`] if proving fails.
 pub fn generate_proof(
-    #[cfg(not(target_arch = "wasm32"))] witness_calculator: &Mutex<WitnessCalculator>,
-    #[cfg(target_arch = "wasm32")] witness_calculator: &mut WitnessCalculator,
     proving_key: &(ProvingKey<Curve>, ConstraintMatrices<Fr>),
     rln_witness: &RLNWitnessInput,
+    graph_data: &[u8],
 ) -> Result<ArkProof<Curve>, ProofError> {
     let inputs = inputs_for_witness_calculation(rln_witness)?
         .into_iter()
         .map(|(name, values)| (name.to_string(), values));
 
     // If in debug mode, we measure and later print time take to compute witness
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
+    let full_assignment = calculate_rln_witness(inputs, graph_data);
 
-    cfg_if! {
-        if #[cfg(target_arch = "wasm32")] {
-            let full_assignment = witness_calculator
-            .calculate_witness_element::<Curve, _>(inputs, false)
-            .map_err(ProofError::WitnessError)?;
-        } else {
-            let full_assignment = witness_calculator
-            .lock()
-            .expect("witness_calculator mutex should not get poisoned")
-            .calculate_witness_element::<Curve, _>(inputs, false)
-            .map_err(ProofError::WitnessError)?;
-        }
-    }
-
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("witness generation took: {:.2?}", now.elapsed());
 
     // Random Values
@@ -705,7 +653,7 @@ pub fn generate_proof(
     let s = Fr::rand(&mut rng);
 
     // If in debug mode, we measure and later print time take to compute proof
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     let now = Instant::now();
     let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
         &proving_key.0,
@@ -717,7 +665,7 @@ pub fn generate_proof(
         full_assignment.as_slice(),
     )?;
 
-    #[cfg(debug_assertions)]
+    #[cfg(test)]
     println!("proof generation took: {:.2?}", now.elapsed());
 
     Ok(proof)
@@ -748,26 +696,69 @@ 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
-///
-/// Returns a JSON object containing the inputs necessary to calculate
-/// the witness with CIRCOM on javascript
+// auxiliary function for serialisation Fr to json using ark serilize
+fn ark_se<S, A: CanonicalSerialize>(a: &A, s: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    let mut bytes = vec![];
+    a.serialize_compressed(&mut bytes)
+        .map_err(serde::ser::Error::custom)?;
+    s.serialize_bytes(&bytes)
+}
+
+// auxiliary function for deserialisation Fr to json using ark serilize
+fn ark_de<'de, D, A: CanonicalDeserialize>(data: D) -> Result<A, D::Error>
+where
+    D: serde::de::Deserializer<'de>,
+{
+    let s: Vec<u8> = serde::de::Deserialize::deserialize(data)?;
+    let a = A::deserialize_compressed_unchecked(s.as_slice());
+    a.map_err(serde::de::Error::custom)
+}
+
+/// Converts a JSON value into [`RLNWitnessInput`] object.
 ///
 /// # Errors
 ///
 /// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
-pub fn get_json_inputs(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
+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();

rln/src/public.rs

@@ -1,33 +1,23 @@
-use crate::circuit::{vk_from_raw, zkey_from_raw, Curve, Fr};
+/// This is the main public API for RLN module. It is used by the FFI, and should be
+/// used by tests etc. as well
+#[cfg(not(feature = "stateless"))]
+use {
+    crate::{circuit::TEST_TREE_HEIGHT, poseidon_tree::PoseidonTree},
+    serde_json::{json, Value},
+    std::str::FromStr,
+    utils::{Hasher, ZerokitMerkleProof, ZerokitMerkleTree},
+};
+
+use crate::circuit::{graph_from_folder, vk_from_raw, zkey_from_folder, zkey_from_raw, Curve, Fr};
 use crate::hashers::{hash_to_field, poseidon_hash as utils_poseidon_hash};
-use crate::poseidon_tree::PoseidonTree;
 use crate::protocol::*;
 use crate::utils::*;
-/// This is the main public API for RLN module. It is used by the FFI, and should be
-/// used by tests etc as well
-use ark_groth16::Proof as ArkProof;
-use ark_groth16::{ProvingKey, VerifyingKey};
+
+use ark_groth16::{Proof as ArkProof, ProvingKey, VerifyingKey};
 use ark_relations::r1cs::ConstraintMatrices;
 use ark_serialize::{CanonicalDeserialize, CanonicalSerialize, Read, Write};
-use cfg_if::cfg_if;
 use color_eyre::{Report, Result};
-use num_bigint::BigInt;
-use std::io::Cursor;
-use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
-
-cfg_if! {
-    if #[cfg(not(target_arch = "wasm32"))] {
-        use std::default::Default;
-        use std::sync::Mutex;
-        use crate::circuit::{circom_from_folder, vk_from_folder, circom_from_raw, zkey_from_folder, TEST_RESOURCES_FOLDER, TEST_TREE_HEIGHT};
-        use ark_circom::WitnessCalculator;
-        use serde_json::{json, Value};
-        use utils::{Hasher};
-        use std::str::FromStr;
-    } else {
-        use std::marker::*;
-    }
-}
+use std::{default::Default, io::Cursor};
 
 /// The application-specific RLN identifier.
 ///
@@ -39,53 +29,43 @@ pub const RLN_IDENTIFIER: &[u8] = b"zerokit/rln/010203040506070809";
 /// It implements the methods required to update the internal Merkle Tree, generate and verify RLN ZK proofs.
 ///
 /// I/O is mostly done using writers and readers implementing `std::io::Write` and `std::io::Read`, respectively.
-pub struct RLN<'a> {
+pub struct RLN {
     proving_key: (ProvingKey<Curve>, ConstraintMatrices<Fr>),
     pub(crate) verification_key: VerifyingKey<Curve>,
+    pub(crate) graph_data: Vec<u8>,
+    #[cfg(not(feature = "stateless"))]
     pub(crate) tree: PoseidonTree,
-
-    // The witness calculator can't be loaded in zerokit. Since this struct
-    // contains a lifetime, a PhantomData is necessary to avoid a compiler
-    // error since the lifetime is not being used
-    #[cfg(not(target_arch = "wasm32"))]
-    pub(crate) witness_calculator: &'a Mutex<WitnessCalculator>,
-    #[cfg(target_arch = "wasm32")]
-    _marker: PhantomData<&'a ()>,
 }
 
-impl RLN<'_> {
+impl RLN {
     /// Creates a new RLN object by loading circuit resources from a folder.
     ///
     /// Input parameters are
     /// - `tree_height`: the height of the internal Merkle tree
-    /// - `input_data`: a reader for the string path of the resource folder containing the ZK circuit (`rln.wasm`), the proving key (`rln_final.zkey`) and the verification key (`verification_key.json`).
+    /// - `input_data`: include `tree_config` a reader for a string containing a json with the merkle tree configuration
     ///
     /// Example:
     /// ```
     /// use std::io::Cursor;
     ///
     /// let tree_height = 20;
-    /// let resources = Cursor::new(json!({"resources_folder": "tree_height_20"});
+    /// let input = Cursor::new(json!({}).to_string());
     ///
     /// // We create a new RLN instance
-    /// let mut rln = RLN::new(tree_height, resources);
+    /// let mut rln = RLN::new(tree_height, input);
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
-    pub fn new<R: Read>(tree_height: usize, mut input_data: R) -> Result<RLN<'static>> {
+    #[cfg(not(feature = "stateless"))]
+    pub fn new<R: Read>(tree_height: usize, mut input_data: R) -> Result<RLN> {
         // We read input
         let mut input: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut input)?;
 
         let rln_config: Value = serde_json::from_str(&String::from_utf8(input)?)?;
-        let resources_folder = rln_config["resources_folder"]
-            .as_str()
-            .unwrap_or(TEST_RESOURCES_FOLDER);
         let tree_config = rln_config["tree_config"].to_string();
 
-        let witness_calculator = circom_from_folder(resources_folder)?;
-
-        let proving_key = zkey_from_folder(resources_folder)?;
-        let verification_key = vk_from_folder(resources_folder)?;
+        let proving_key = zkey_from_folder();
+        let verification_key = &proving_key.0.vk;
+        let graph_data = graph_from_folder();
 
         let tree_config: <PoseidonTree as ZerokitMerkleTree>::Config = if tree_config.is_empty() {
             <PoseidonTree as ZerokitMerkleTree>::Config::default()
@@ -101,12 +81,33 @@ impl RLN<'_> {
         )?;
 
         Ok(RLN {
-            witness_calculator,
-            proving_key,
-            verification_key,
+            proving_key: proving_key.to_owned(),
+            verification_key: verification_key.to_owned(),
+            graph_data: graph_data.to_vec(),
+            #[cfg(not(feature = "stateless"))]
             tree,
-            #[cfg(target_arch = "wasm32")]
-            _marker: PhantomData,
+        })
+    }
+
+    /// Creates a new stateless RLN object by loading circuit resources from a folder.
+    ///
+    /// Example:
+    ///
+    /// ```
+    /// // We create a new RLN instance
+    /// let mut rln = RLN::new();
+    /// ```
+    #[cfg_attr(docsrs, doc(cfg(feature = "stateless")))]
+    #[cfg(feature = "stateless")]
+    pub fn new() -> Result<RLN> {
+        let proving_key = zkey_from_folder();
+        let verification_key = &proving_key.0.vk;
+        let graph_data = graph_from_folder();
+
+        Ok(RLN {
+            proving_key: proving_key.to_owned(),
+            verification_key: verification_key.to_owned(),
+            graph_data: graph_data.to_vec(),
         })
     }
 
@@ -114,10 +115,8 @@ impl RLN<'_> {
     ///
     /// Input parameters are
     /// - `tree_height`: the height of the internal Merkle tree
-    /// - `circom_vec`: a byte vector containing the ZK circuit (`rln.wasm`) as binary file
-    /// - `zkey_vec`: a byte vector containing to the proving key (`rln_final.zkey`) as binary file
-    /// - `vk_vec`: a byte vector containing to the verification key (`verification_key.json`) as binary file
-    /// - `tree_config`: a reader for a string containing a json with the merkle tree configuration
+    /// - `zkey_vec`: a byte vector containing to the proving key (`rln_final.zkey`)  or (`rln_final.arkzkey`) as binary file
+    /// - `tree_config_input`: a reader for a string containing a json with the merkle tree configuration
     ///
     /// Example:
     /// ```
@@ -128,17 +127,18 @@ impl RLN<'_> {
     /// let resources_folder = "./resources/tree_height_20/";
     ///
     /// let mut resources: Vec<Vec<u8>> = Vec::new();
-    /// for filename in ["rln.wasm", "rln_final.zkey", "verification_key.json"] {
+    /// for filename in ["rln_final.zkey", "graph.bin"] {
     ///     let fullpath = format!("{resources_folder}{filename}");
     ///     let mut file = File::open(&fullpath).expect("no file found");
     ///     let metadata = std::fs::metadata(&fullpath).expect("unable to read metadata");
     ///     let mut buffer = vec![0; metadata.len() as usize];
     ///     file.read_exact(&mut buffer).expect("buffer overflow");
     ///     resources.push(buffer);
-    ///     let tree_config = "{}".to_string();
-    ///     let tree_config_buffer = &Buffer::from(tree_config.as_bytes());
     /// }
     ///
+    /// let tree_config = "".to_string();
+    /// let tree_config_buffer = &Buffer::from(tree_config.as_bytes());
+    ///
     /// let mut rln = RLN::new_with_params(
     ///     tree_height,
     ///     resources[0].clone(),
@@ -147,19 +147,15 @@ impl RLN<'_> {
     ///     tree_config_buffer,
     /// );
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
+    #[cfg(not(feature = "stateless"))]
     pub fn new_with_params<R: Read>(
         tree_height: usize,
-        circom_vec: Vec<u8>,
         zkey_vec: Vec<u8>,
-        vk_vec: Vec<u8>,
+        graph_data: Vec<u8>,
         mut tree_config_input: R,
-    ) -> Result<RLN<'static>> {
-        #[cfg(not(target_arch = "wasm32"))]
-        let witness_calculator = circom_from_raw(circom_vec)?;
-
+    ) -> Result<RLN> {
         let proving_key = zkey_from_raw(&zkey_vec)?;
-        let verification_key = vk_from_raw(&vk_vec, &zkey_vec)?;
+        let verification_key = vk_from_raw(&zkey_vec)?;
 
         let mut tree_config_vec: Vec<u8> = Vec::new();
         tree_config_input.read_to_end(&mut tree_config_vec)?;
@@ -179,33 +175,51 @@ impl RLN<'_> {
         )?;
 
         Ok(RLN {
-            witness_calculator,
             proving_key,
             verification_key,
+            graph_data,
+            #[cfg(not(feature = "stateless"))]
             tree,
         })
     }
 
-    #[cfg(target_arch = "wasm32")]
-    pub fn new_with_params(
-        tree_height: usize,
-        zkey_vec: Vec<u8>,
-        vk_vec: Vec<u8>,
-    ) -> Result<RLN<'static>> {
-        #[cfg(not(target_arch = "wasm32"))]
-        let witness_calculator = circom_from_raw(circom_vec)?;
-
+    /// Creates a new stateless RLN object by passing circuit resources as byte vectors.
+    ///
+    /// Input parameters are
+    /// - `zkey_vec`: a byte vector containing to the proving key (`rln_final.zkey`)  or (`rln_final.arkzkey`) as binary file
+    ///
+    /// Example:
+    /// ```
+    /// use std::fs::File;
+    /// use std::io::Read;
+    ///
+    /// let resources_folder = "./resources/tree_height_20/";
+    ///
+    /// let mut resources: Vec<Vec<u8>> = Vec::new();
+    /// for filename in ["rln_final.zkey", "graph.bin"] {
+    ///     let fullpath = format!("{resources_folder}{filename}");
+    ///     let mut file = File::open(&fullpath).expect("no file found");
+    ///     let metadata = std::fs::metadata(&fullpath).expect("unable to read metadata");
+    ///     let mut buffer = vec![0; metadata.len() as usize];
+    ///     file.read_exact(&mut buffer).expect("buffer overflow");
+    ///     resources.push(buffer);
+    /// }
+    ///
+    /// let mut rln = RLN::new_with_params(
+    ///     resources[0].clone(),
+    ///     resources[1].clone(),
+    ///     resources[2].clone(),
+    /// );
+    /// ```
+    #[cfg(feature = "stateless")]
+    pub fn new_with_params(zkey_vec: Vec<u8>, graph_data: Vec<u8>) -> Result<RLN> {
         let proving_key = zkey_from_raw(&zkey_vec)?;
-        let verification_key = vk_from_raw(&vk_vec, &zkey_vec)?;
-
-        // We compute a default empty tree
-        let tree = PoseidonTree::default(tree_height)?;
+        let verification_key = vk_from_raw(&zkey_vec)?;
 
         Ok(RLN {
             proving_key,
             verification_key,
-            tree,
-            _marker: PhantomData,
+            graph_data,
         })
     }
 
@@ -218,6 +232,7 @@ impl RLN<'_> {
     ///
     /// Input values are:
     /// - `tree_height`: the height of the Merkle tree.
+    #[cfg(not(feature = "stateless"))]
     pub fn set_tree(&mut self, tree_height: usize) -> Result<()> {
         // We compute a default empty tree of desired height
         self.tree = PoseidonTree::default(tree_height)?;
@@ -248,6 +263,7 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(serialize_field_element(rate_commitment));
     /// rln.set_leaf(id_index, &mut buffer).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn set_leaf<R: Read>(&mut self, index: usize, mut input_data: R) -> Result<()> {
         // We read input
         let mut leaf_byte: Vec<u8> = Vec::new();
@@ -265,6 +281,9 @@ impl RLN<'_> {
     /// Input values are:
     /// - `index`: the index of the leaf
     ///
+    /// Output values are:
+    /// - `output_data`: a writer receiving the serialization of the metadata
+    ///
     /// Example:
     /// ```
     /// use crate::protocol::*;
@@ -274,6 +293,7 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(Vec::<u8>::new());
     /// rln.get_leaf(id_index, &mut buffer).unwrap();
     /// let rate_commitment = deserialize_field_element(&buffer.into_inner()).unwrap();
+    #[cfg(not(feature = "stateless"))]
     pub fn get_leaf<W: Write>(&self, index: usize, mut output_data: W) -> Result<()> {
         // We get the leaf at input index
         let leaf = self.tree.get(index)?;
@@ -316,6 +336,7 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
     /// rln.set_leaves_from(index, &mut buffer).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn set_leaves_from<R: Read>(&mut self, index: usize, mut input_data: R) -> Result<()> {
         // We read input
         let mut leaves_byte: Vec<u8> = Vec::new();
@@ -336,6 +357,7 @@ impl RLN<'_> {
     ///
     /// Input values are:
     /// - `input_data`: a reader for the serialization of multiple leaf values (serialization done with [`rln::utils::vec_fr_to_bytes_le`](crate::utils::vec_fr_to_bytes_le))
+    #[cfg(not(feature = "stateless"))]
     pub fn init_tree_with_leaves<R: Read>(&mut self, input_data: R) -> Result<()> {
         // reset the tree
         // NOTE: this requires the tree to be initialized with the correct height initially
@@ -384,8 +406,9 @@ impl RLN<'_> {
     /// // We atomically add leaves and remove indices from the tree
     /// let mut leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
     /// let mut indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices));
-    /// rln.set_leaves_from(index, &mut leaves_buffer, indices_buffer).unwrap();
+    /// rln.atomic_operation(index, &mut leaves_buffer, indices_buffer).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn atomic_operation<R: Read>(
         &mut self,
         index: usize,
@@ -411,6 +434,7 @@ impl RLN<'_> {
         Ok(())
     }
 
+    #[cfg(not(feature = "stateless"))]
     pub fn leaves_set(&mut self) -> usize {
         self.tree.leaves_set()
     }
@@ -458,6 +482,7 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
     /// rln.set_next_leaf(&mut buffer).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn set_next_leaf<R: Read>(&mut self, mut input_data: R) -> Result<()> {
         // We read input
         let mut leaf_byte: Vec<u8> = Vec::new();
@@ -470,7 +495,7 @@ impl RLN<'_> {
         Ok(())
     }
 
-    /// Sets the value of the leaf at position index to the harcoded default value.
+    /// Sets the value of the leaf at position index to the hardcoded default value.
     ///
     /// This function does not change the internal Merkle tree `next_index` value.
     ///
@@ -483,6 +508,7 @@ impl RLN<'_> {
     /// let index = 10;
     /// rln.delete_leaf(index).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn delete_leaf(&mut self, index: usize) -> Result<()> {
         self.tree.delete(index)?;
         Ok(())
@@ -500,6 +526,7 @@ impl RLN<'_> {
     /// let metadata = b"some metadata";
     /// rln.set_metadata(metadata).unwrap();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn set_metadata(&mut self, metadata: &[u8]) -> Result<()> {
         self.tree.set_metadata(metadata)?;
         Ok(())
@@ -519,6 +546,7 @@ impl RLN<'_> {
     /// rln.get_metadata(&mut buffer).unwrap();
     /// let metadata = buffer.into_inner();
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn get_metadata<W: Write>(&self, mut output_data: W) -> Result<()> {
         let metadata = self.tree.metadata()?;
         output_data.write_all(&metadata)?;
@@ -538,6 +566,7 @@ impl RLN<'_> {
     /// rln.get_root(&mut buffer).unwrap();
     /// let (root, _) = bytes_le_to_fr(&buffer.into_inner());
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn get_root<W: Write>(&self, mut output_data: W) -> Result<()> {
         let root = self.tree.root();
         output_data.write_all(&fr_to_bytes_le(&root))?;
@@ -545,6 +574,34 @@ impl RLN<'_> {
         Ok(())
     }
 
+    /// Returns the root of subtree in the Merkle tree
+    ///
+    /// Output values are:
+    /// - `output_data`: a writer receiving the serialization of the node value (serialization done with [`rln::utils::fr_to_bytes_le`](crate::utils::fr_to_bytes_le))
+    ///
+    /// Example
+    /// ```
+    /// use rln::utils::*;
+    ///
+    /// let mut buffer = Cursor::new(Vec::<u8>::new());
+    /// let level = 1;
+    /// let index = 2;
+    /// rln.get_subtree_root(level, index, &mut buffer).unwrap();
+    /// let (subroot, _) = bytes_le_to_fr(&buffer.into_inner());
+    /// ```
+    #[cfg(not(feature = "stateless"))]
+    pub fn get_subtree_root<W: Write>(
+        &self,
+        level: usize,
+        index: usize,
+        mut output_data: W,
+    ) -> Result<()> {
+        let subroot = self.tree.get_subtree_root(level, index)?;
+        output_data.write_all(&fr_to_bytes_le(&subroot))?;
+
+        Ok(())
+    }
+
     /// Returns the Merkle proof of the leaf at position index
     ///
     /// Input values are:
@@ -566,6 +623,7 @@ impl RLN<'_> {
     /// let (path_elements, read) = bytes_le_to_vec_fr(&buffer_inner);
     /// let (identity_path_index, _) = bytes_le_to_vec_u8(&buffer_inner[read..].to_vec());
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn get_proof<W: Write>(&self, index: usize, mut output_data: W) -> Result<()> {
         let merkle_proof = self.tree.proof(index).expect("proof should exist");
         let path_elements = merkle_proof.get_path_elements();
@@ -577,13 +635,52 @@ impl RLN<'_> {
         Ok(())
     }
 
+    /// Returns indices of leaves in the tree are set to zero (upto the final leaf that was set).
+    ///
+    /// Output values are:
+    /// - `output_data`: a writer receiving the serialization of the indices of leaves.
+    ///
+    /// Example
+    /// ```
+    /// use rln::circuit::Fr;
+    /// use rln::utils::*;
+    ///
+    /// let start_index = 5;
+    /// let no_of_leaves = 256;
+    ///
+    /// // We generate a vector of random leaves
+    /// let mut leaves: Vec<Fr> = Vec::new();
+    /// let mut rng = thread_rng();
+    /// for _ in 0..no_of_leaves {
+    ///     let (_, id_commitment) = keygen();
+    ///     let rate_commitment = poseidon_hash(&[id_commitment, 1.into()]);
+    ///     leaves.push(rate_commitment);
+    /// }
+    ///
+    /// // We add leaves in a batch into the tree
+    /// let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves));
+    /// rln.set_leaves_from(index, &mut buffer).unwrap();
+    ///
+    /// // Get indices of first empty leaves upto start_index
+    /// 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, 3, 4]);
+    /// ```
+    #[cfg(not(feature = "stateless"))]
+    pub fn get_empty_leaves_indices<W: Write>(&self, mut output_data: W) -> Result<()> {
+        let idxs = self.tree.get_empty_leaves_indices();
+        idxs.serialize_compressed(&mut output_data)?;
+        Ok(())
+    }
+
     ////////////////////////////////////////////////////////
     // zkSNARK APIs
     ////////////////////////////////////////////////////////
-    /// Computes a zkSNARK RLN proof using a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput).
+    /// Computes a zkSNARK RLN proof using a [`RLNWitnessInput`].
     ///
     /// Input values are:
-    /// - `input_data`: a reader for the serialization of a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object, containing the public and private inputs to the ZK circuits (serialization done using [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness))
+    /// - `input_data`: a reader for the serialization of a [`RLNWitnessInput`] object, containing the public and private inputs to the ZK circuits (serialization done using [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness))
     ///
     /// Output values are:
     /// - `output_data`: a writer receiving the serialization of the zkSNARK proof
@@ -601,7 +698,6 @@ impl RLN<'_> {
     /// rln.prove(&mut input_buffer, &mut output_buffer).unwrap();
     /// let zk_proof = output_buffer.into_inner();
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
     pub fn prove<R: Read, W: Write>(
         &mut self,
         mut input_data: R,
@@ -612,13 +708,7 @@ impl RLN<'_> {
         input_data.read_to_end(&mut serialized)?;
         let (rln_witness, _) = deserialize_witness(&serialized)?;
 
-        /*
-        if self.witness_calculator.is_none() {
-            self.witness_calculator = CIRCOM(&self.resources_folder);
-        }
-        */
-
-        let proof = generate_proof(self.witness_calculator, &self.proving_key, &rln_witness)?;
+        let proof = generate_proof(&self.proving_key, &rln_witness, &self.graph_data)?;
 
         // Note: we export a serialization of ark-groth16::Proof not semaphore::Proof
         proof.serialize_compressed(&mut output_data)?;
@@ -629,7 +719,8 @@ impl RLN<'_> {
     /// Verifies a zkSNARK RLN proof.
     ///
     /// Input values are:
-    /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values, i.e. `[ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]`, where <_> indicates the byte length.
+    /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values,
+    ///   i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]`, where <_> indicates the byte length.
     ///
     /// The function returns true if the zkSNARK proof is valid with respect to the provided circuit output values, false otherwise.
     ///
@@ -664,7 +755,7 @@ impl RLN<'_> {
     pub fn verify<R: Read>(&self, mut input_data: R) -> Result<bool> {
         // Input data is serialized for Curve as:
         // serialized_proof (compressed, 4*32 bytes) || serialized_proof_values (6*32 bytes), i.e.
-        // [ proof<128> | root<32> | external_nullifier<32> | share_x<32> | share_y<32> | nullifier<32> ]
+        // [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
         let mut input_byte: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut input_byte)?;
         let proof = ArkProof::deserialize_compressed(&mut Cursor::new(&input_byte[..128]))?;
@@ -676,18 +767,19 @@ impl RLN<'_> {
         Ok(verified)
     }
 
-    /// Computes a zkSNARK RLN proof from the identity secret, the Merkle tree index, the epoch and signal.
+    /// Computes a zkSNARK RLN proof from the identity secret, the Merkle tree index, the user message limit, the message id, the external nullifier (which include epoch and rln identifier) and signal.
     ///
     /// Input values are:
-    /// - `input_data`: a reader for the serialization of `[ identity_secret<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]`
+    /// - `input_data`: a reader for the serialization of `[ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]`
     ///
     /// Output values are:
-    /// - `output_data`: a writer receiving the serialization of the zkSNARK proof and the circuit evaluations outputs, i.e. `[ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]`
+    /// - `output_data`: a writer receiving the serialization of the zkSNARK proof and the circuit evaluations outputs, i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]`
     ///
-    /// Example    
+    /// Example
     /// ```
     /// use rln::protocol::*:
     /// use rln::utils::*;
+    /// use rln::hashers::*;
     ///
     /// // Generate identity pair
     /// let (identity_secret_hash, id_commitment) = keygen();
@@ -698,30 +790,35 @@ impl RLN<'_> {
     /// let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
     /// rln.set_leaf(identity_index, &mut buffer).unwrap();
     ///
-    /// // We generate a random signal
-    /// let mut rng = rand::thread_rng();
-    /// let signal: [u8; 32] = rng.gen();
     /// // We generate a random epoch
     /// let epoch = hash_to_field(b"test-epoch");
+    /// // We generate a random rln_identifier
+    /// let rln_identifier = hash_to_field(b"test-rln-identifier");
+    /// // We generate a external nullifier
+    /// let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
+    /// // We choose a message_id satisfy 0 <= message_id < MESSAGE_LIMIT
+    /// let message_id = Fr::from(1);
     ///
     /// // We prepare input for generate_rln_proof API
-    /// // input_data is [ identity_secret<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]
-    /// let mut serialized: Vec<u8> = Vec::new();
-    /// serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
-    /// serialized.append(&mut normalize_usize(identity_index));
-    /// serialized.append(&mut fr_to_bytes_le(&epoch));
-    /// serialized.append(&mut normalize_usize(signal_len).resize(8,0));
-    /// serialized.append(&mut signal.to_vec());
+    /// // input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
+    /// let prove_input = prepare_prove_input(
+    ///     identity_secret_hash,
+    ///     identity_index,
+    ///     user_message_limit,
+    ///     message_id,
+    ///     external_nullifier,
+    ///     &signal,
+    /// );
     ///
     /// let mut input_buffer = Cursor::new(serialized);
     /// let mut output_buffer = Cursor::new(Vec::<u8>::new());
     /// rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
     ///     .unwrap();
     ///
-    /// // proof_data is [ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> |  rln_identifier<32> ]
+    /// // proof_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]
     /// let mut proof_data = output_buffer.into_inner();
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
+    #[cfg(not(feature = "stateless"))]
     pub fn generate_rln_proof<R: Read, W: Write>(
         &mut self,
         mut input_data: R,
@@ -733,7 +830,7 @@ impl RLN<'_> {
         let (rln_witness, _) = proof_inputs_to_rln_witness(&mut self.tree, &witness_byte)?;
         let proof_values = proof_values_from_witness(&rln_witness)?;
 
-        let proof = generate_proof(self.witness_calculator, &self.proving_key, &rln_witness)?;
+        let proof = generate_proof(&self.proving_key, &rln_witness, &self.graph_data)?;
 
         // Note: we export a serialization of ark-groth16::Proof not semaphore::Proof
         // This proof is compressed, i.e. 128 bytes long
@@ -743,22 +840,21 @@ impl RLN<'_> {
         Ok(())
     }
 
-    // TODO: this function seems to use redundant witness (as bigint and serialized) and should be refactored
     // Generate RLN Proof using a witness calculated from outside zerokit
     //
-    // output_data is  [ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]
+    // output_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]
     // we skip it from documentation for now
-    #[doc(hidden)]
-    pub fn generate_rln_proof_with_witness<W: Write>(
+    pub fn generate_rln_proof_with_witness<R: Read, W: Write>(
         &mut self,
-        calculated_witness: Vec<BigInt>,
-        rln_witness_vec: Vec<u8>,
+        mut input_data: R,
         mut output_data: W,
     ) -> Result<()> {
-        let (rln_witness, _) = deserialize_witness(&rln_witness_vec[..])?;
+        let mut witness_byte: Vec<u8> = Vec::new();
+        input_data.read_to_end(&mut witness_byte)?;
+        let (rln_witness, _) = deserialize_witness(&witness_byte)?;
         let proof_values = proof_values_from_witness(&rln_witness)?;
 
-        let proof = generate_proof_with_witness(calculated_witness, &self.proving_key).unwrap();
+        let proof = generate_proof(&self.proving_key, &rln_witness, &self.graph_data)?;
 
         // Note: we export a serialization of ark-groth16::Proof not semaphore::Proof
         // This proof is compressed, i.e. 128 bytes long
@@ -770,11 +866,12 @@ impl RLN<'_> {
     /// Verifies a zkSNARK RLN proof against the provided proof values and the state of the internal Merkle tree.
     ///
     /// Input values are:
-    /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values and the signal information, i.e. `[ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> | signal_len<8> | signal<var> ]`
+    /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values and the signal information,
+    ///   i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var>]`, where <_> indicates the byte length.
     ///
     /// The function returns true if the zkSNARK proof is valid with respect to the provided circuit output values and signal. Returns false otherwise.
     ///
-    /// Note that contrary to [`verify`](crate::public::RLN::verify), this function takes additionaly as input the signal and further verifies if
+    /// Note that contrary to [`verify`](crate::public::RLN::verify), this function takes additionally as input the signal and further verifies if
     /// - the Merkle tree root corresponds to the root provided as input;
     /// - the input signal corresponds to the Shamir's x coordinate provided as input
     /// - the hardcoded application [RLN identifier](crate::public::RLN_IDENTIFIER) corresponds to the RLN identifier provided as input
@@ -784,16 +881,16 @@ impl RLN<'_> {
     /// // proof_data is computed as in the example code snippet provided for rln::public::RLN::generate_rln_proof
     ///
     /// // We prepare input for verify_rln_proof API
-    /// // input_data is [ proof<128> | share_y<32> | nullifier<32> | root<32> | epoch<32> | share_x<32> | rln_identifier<32> | signal_len<8> | signal<var> ]
+    /// // input_data is  `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var>]`
     /// // that is [ proof_data || signal_len<8> | signal<var> ]
-    /// proof_data.append(&mut normalize_usize(signal_len));
-    /// proof_data.append(&mut signal.to_vec());
+    /// let verify_input = prepare_verify_input(proof_data, &signal);
     ///
-    /// let mut input_buffer = Cursor::new(proof_data);
+    /// let mut input_buffer = Cursor::new(verify_input);
     /// let verified = rln.verify_rln_proof(&mut input_buffer).unwrap();
     ///
     /// assert!(verified);
     /// ```
+    #[cfg(not(feature = "stateless"))]
     pub fn verify_rln_proof<R: Read>(&self, mut input_data: R) -> Result<bool> {
         let mut serialized: Vec<u8> = Vec::new();
         input_data.read_to_end(&mut serialized)?;
@@ -821,15 +918,15 @@ impl RLN<'_> {
     /// Verifies a zkSNARK RLN proof against the provided proof values and a set of allowed Merkle tree roots.
     ///
     /// Input values are:
-    /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values and the signal information, i.e. `[ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> | signal_len<8> | signal<var> ]`
-    /// - `roots_data`: a reader for the serialization of a vector of roots, i.e. `[ number_of_roots<8> | root_1<32> | ... | root_n<32> ]` (number_of_roots is a uint64 in little-endian, roots are serialized using `rln::utils::fr_to_bytes_le`))
+    /// - `input_data`: a reader for the serialization of the RLN zkSNARK proof concatenated with a serialization of the circuit output values and the signal information, i.e. `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var>]`
+    /// - `roots_data`: a reader for the serialization of a vector of roots, i.e. `[ number_of_roots<8> | root_1<32> | ... | root_n<32> ]` (number_of_roots is an uint64 in little-endian, roots are serialized using `rln::utils::fr_to_bytes_le`)
     ///
     /// The function returns true if the zkSNARK proof is valid with respect to the provided circuit output values, signal and roots. Returns false otherwise.
     ///
     /// Note that contrary to [`verify_rln_proof`](crate::public::RLN::verify_rln_proof), this function does not check if the internal Merkle tree root corresponds to the root provided as input, but rather checks if the root provided as input in `input_data` corresponds to one of the roots serialized in `roots_data`.
     ///
     /// If `roots_data` contains no root (is empty), root validation is skipped and the proof will be correctly verified only if the other proof values results valid (i.e., zk-proof, signal, x-coordinate, RLN identifier)
-    ///   
+    ///
     /// Example
     /// ```
     /// // proof_data is computed as in the example code snippet provided for rln::public::RLN::generate_rln_proof
@@ -864,7 +961,7 @@ impl RLN<'_> {
     /// roots_serialized.append(&mut fr_to_bytes_le(&root));
     /// roots_buffer = Cursor::new(roots_serialized.clone());
     /// let verified = rln
-    ///     .verify_with_roots(&mut input_buffer.clone(), &mut roots_buffer)
+    ///     .verify_with_roots(&mut input_buffer, &mut roots_buffer)
     ///     .unwrap();
     ///
     /// assert!(verified);
@@ -967,7 +1064,7 @@ impl RLN<'_> {
     /// Generated credentials are compatible with [Semaphore](https://semaphore.appliedzkp.org/docs/guides/identities)'s credentials.
     ///
     /// Output values are:
-    /// - `output_data`: a writer receiving the serialization of the identity tapdoor, identity nullifier, identity secret and identity commitment (serialization done with `rln::utils::fr_to_bytes_le`)
+    /// - `output_data`: a writer receiving the serialization of the identity trapdoor, identity nullifier, identity secret and identity commitment (serialization done with `rln::utils::fr_to_bytes_le`)
     ///
     /// Example
     /// ```
@@ -1042,7 +1139,7 @@ impl RLN<'_> {
     /// - `input_data`: a reader for the byte vector containing the seed
     ///
     /// Output values are:
-    /// - `output_data`: a writer receiving the serialization of the identity tapdoor, identity nullifier, identity secret and identity commitment (serialization done with `rln::utils::fr_to_bytes_le`)
+    /// - `output_data`: a writer receiving the serialization of the identity trapdoor, identity nullifier, identity secret and identity commitment (serialization done with `rln::utils::fr_to_bytes_le`)
     ///
     /// Example
     /// ```
@@ -1076,10 +1173,12 @@ impl RLN<'_> {
         Ok(())
     }
 
-    /// Recovers the identity secret from two set of proof values computed for same secret in same epoch.
+    /// Recovers the identity secret from two set of proof values computed for same secret in same epoch with same rln identifier.
     ///
     /// Input values are:
-    /// - `input_proof_data_1`: a reader for the serialization of a RLN zkSNARK proof concatenated with a serialization of the circuit output values and -optionally- the signal information, i.e. either `[ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]` or `[ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> | signal_len<8> | signal<var> ]` (to maintain compatibility with both output of [`generate_rln_proof`](crate::public::RLN::generate_rln_proof) and input of [`verify_rln_proof`](crate::public::RLN::verify_rln_proof))
+    /// - `input_proof_data_1`: a reader for the serialization of a RLN zkSNARK proof concatenated with a serialization of the circuit output values and -optionally- the signal information,
+    ///   i.e. either `[proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32>]`
+    ///   or `[ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]` (to maintain compatibility with both output of [`generate_rln_proof`](crate::public::RLN::generate_rln_proof) and input of [`verify_rln_proof`](crate::public::RLN::verify_rln_proof))
     /// - `input_proof_data_2`: same as `input_proof_data_1`
     ///
     /// Output values are:
@@ -1087,7 +1186,7 @@ impl RLN<'_> {
     ///
     /// Example
     /// ```
-    /// // identity_secret_hash, proof_data_1 and proof_data_2 are computed as in the example code snippet provided for rln::public::RLN::generate_rln_proof using same identity secret and epoch (but not necessarily same signal)
+    /// // identity_secret_hash, proof_data_1 and proof_data_2 are computed as in the example code snippet provided for rln::public::RLN::generate_rln_proof using same identity secret, epoch and rln identifier (but not necessarily same signal)
     ///
     /// let mut input_proof_data_1 = Cursor::new(proof_data_1);
     /// let mut input_proof_data_2 = Cursor::new(proof_data_2);
@@ -1114,7 +1213,7 @@ impl RLN<'_> {
         mut input_proof_data_2: R,
         mut output_data: W,
     ) -> Result<()> {
-        // We serialize_compressed the two proofs and we get the corresponding RLNProofValues objects
+        // We serialize_compressed the two proofs, and we get the corresponding RLNProofValues objects
         let mut serialized: Vec<u8> = Vec::new();
         input_proof_data_1.read_to_end(&mut serialized)?;
         // We skip deserialization of the zk-proof at the beginning
@@ -1127,10 +1226,10 @@ impl RLN<'_> {
         let (proof_values_2, _) = deserialize_proof_values(&serialized[128..]);
         let external_nullifier_2 = proof_values_2.external_nullifier;
 
-        // We continue only if the proof values are for the same epoch
-        // The idea is that proof values that go as input to this function are verified first (with zk-proof verify), hence ensuring validity of epoch and other fields.
+        // We continue only if the proof values are for the same external nullifier (which includes epoch and rln identifier)
+        // The idea is that proof values that go as input to this function are verified first (with zk-proof verify), hence ensuring validity of external nullifier and other fields.
         // Only in case all fields are valid, an external_nullifier for the message will be stored (otherwise signal/proof will be simply discarded)
-        // If the nullifier matches one already seen, we can recovery of identity secret.
+        // If the nullifier matches one already seen, we can recover of identity secret.
         if external_nullifier_1 == external_nullifier_2 {
             // We extract the two shares
             let share1 = (proof_values_1.x, proof_values_1.y);
@@ -1150,12 +1249,13 @@ impl RLN<'_> {
         Ok(())
     }
 
-    /// Returns the serialization of a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) populated from the identity secret, the Merkle tree index, the epoch and signal.
+    /// Returns the serialization of a [`RLNWitnessInput`] populated from the identity secret, the Merkle tree index, the user message limit, the message id, the external nullifier (which include epoch and rln identifier) and signal.
     ///
     /// Input values are:
-    /// - `input_data`: a reader for the serialization of `[ identity_secret<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]`
+    /// - `input_data`: a reader for the serialization of `[ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]`
     ///
-    /// The function returns the corresponding [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object serialized using [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness)).
+    /// The function returns the corresponding [`RLNWitnessInput`] object serialized using [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness).
+    #[cfg(not(feature = "stateless"))]
     pub fn get_serialized_rln_witness<R: Read>(&mut self, mut input_data: R) -> Result<Vec<u8>> {
         // We read input RLN witness and we serialize_compressed it
         let mut witness_byte: Vec<u8> = Vec::new();
@@ -1165,32 +1265,52 @@ impl RLN<'_> {
         serialize_witness(&rln_witness)
     }
 
-    /// Converts a byte serialization of a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object to the corresponding JSON serialization.
+    /// Converts a byte serialization of a [`RLNWitnessInput`] object to the corresponding JSON serialization.
     ///
     /// Input values are:
-    /// - `serialized_witness`: the byte serialization of a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object (serialization done with  [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness)).
+    /// - `serialized_witness`: the byte serialization of a [`RLNWitnessInput`] object (serialization done with  [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness)).
     ///
-    /// The function returns the corresponding JSON encoding of the input [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object.
+    /// The function returns the corresponding JSON encoding of the input [`RLNWitnessInput`] object.
     pub fn get_rln_witness_json(&mut self, serialized_witness: &[u8]) -> Result<serde_json::Value> {
         let (rln_witness, _) = deserialize_witness(serialized_witness)?;
-        get_json_inputs(&rln_witness)
+        rln_witness_to_json(&rln_witness)
+    }
+
+    /// Converts a byte serialization of a [`RLNWitnessInput`] object to the corresponding JSON serialization.
+    /// Before serialization the data will be translated into big int for further calculation in the witness calculator.
+    ///
+    /// Input values are:
+    /// - `serialized_witness`: the byte serialization of a [`RLNWitnessInput`] object (serialization done with  [`rln::protocol::serialize_witness`](crate::protocol::serialize_witness)).
+    ///
+    /// The function returns the corresponding JSON encoding of the input [`RLNWitnessInput`] object.
+    pub fn get_rln_witness_bigint_json(
+        &mut self,
+        serialized_witness: &[u8],
+    ) -> Result<serde_json::Value> {
+        let (rln_witness, _) = deserialize_witness(serialized_witness)?;
+        rln_witness_to_bigint_json(&rln_witness)
     }
 
     /// Closes the connection to the Merkle tree database.
     /// This function should be called before the RLN object is dropped.
     /// If not called, the connection will be closed when the RLN object is dropped.
     /// This improves robustness of the tree.
+    #[cfg(not(feature = "stateless"))]
     pub fn flush(&mut self) -> Result<()> {
         self.tree.close_db_connection()
     }
 }
 
-#[cfg(not(target_arch = "wasm32"))]
-impl Default for RLN<'_> {
+impl Default for RLN {
     fn default() -> Self {
-        let tree_height = TEST_TREE_HEIGHT;
-        let buffer = Cursor::new(json!({ "resources_folder": TEST_RESOURCES_FOLDER }).to_string());
-        Self::new(tree_height, buffer).unwrap()
+        #[cfg(not(feature = "stateless"))]
+        {
+            let tree_height = TEST_TREE_HEIGHT;
+            let buffer = Cursor::new(json!({}).to_string());
+            Self::new(tree_height, buffer).unwrap()
+        }
+        #[cfg(feature = "stateless")]
+        Self::new().unwrap()
     }
 }
 

rln/src/utils.rs

@@ -1,22 +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).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"));
@@ -35,6 +39,7 @@ pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
     }
 }
 
+#[inline(always)]
 pub fn bytes_le_to_fr(input: &[u8]) -> (Fr, usize) {
     let el_size = fr_byte_size();
     (
@@ -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 +122,26 @@ 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)
+#[inline(always)]
+pub fn normalize_usize(input: usize) -> [u8; 8] {
+    input.to_le_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)))
-}
-*/

rln/tests/poseidon_tree.rs

@@ -4,48 +4,25 @@
 
 #[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();
             let proof = tree_opt.proof(i).expect("index should be set");
             assert_eq!(proof.leaf_index(), i);
         }
@@ -55,26 +32,108 @@ 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 = 6;
+
+        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);
+
+        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());
+        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(), [0, 1, 2, 3])
+            .unwrap();
+        assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
+
+        // check remove_indices inside override_range function
+        tree.override_range(0, [], [0, 1]).unwrap();
+        assert_eq!(tree.get_empty_leaves_indices(), vec![0, 1, 2, 3]);
+
+        // check set_range inside override_range function
+        tree.override_range(0, leaves_2.clone(), []).unwrap();
+        assert_eq!(tree.get_empty_leaves_indices(), vec![2, 3]);
+
+        let leaves_4: Vec<Fr> = (0..4).map(|s| Fr::from(s as i32)).collect();
+        // check if the indexes for write and delete are the same
+        tree.override_range(0, leaves_4.clone(), [0, 1, 2, 3])
+            .unwrap();
+        assert!(tree.get_empty_leaves_indices().is_empty());
+
+        // check if indexes for deletion are before indexes for overwriting
+        tree.override_range(4, leaves_4.clone(), [0, 1, 2, 3])
+            .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(), [0, 1, 2, 3])
+            .unwrap();
+        // The result will be like this, because in the set_range function in pmtree
+        // the next_index value is increased not by the number of elements to insert,
+        // but by the union of indices for deleting and inserting.
+        // + we've already set to 6 and 7 in previous test
+        assert_eq!(tree.get_empty_leaves_indices(), vec![0, 1, 8, 9, 10, 11]);
     }
 }

rln/tests/protocol.rs

@@ -1,10 +1,8 @@
 #[cfg(test)]
 mod test {
     use ark_ff::BigInt;
-    use rln::circuit::{
-        circom_from_folder, vk_from_folder, zkey_from_folder, Fr, TEST_RESOURCES_FOLDER,
-        TEST_TREE_HEIGHT,
-    };
+    use rln::circuit::{graph_from_folder, zkey_from_folder};
+    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
     use rln::hashers::{hash_to_field, poseidon_hash};
     use rln::poseidon_tree::PoseidonTree;
     use rln::protocol::*;
@@ -13,65 +11,9 @@ mod test {
 
     type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
 
-    // Input generated with https://github.com/oskarth/zk-kit/commit/b6a872f7160c7c14e10a0ea40acab99cbb23c9a8
-    const WITNESS_JSON_20: &str = r#"
-            {
-                "externalNullifier": "21074405743803627666274838159589343934394162804826017440941339048886754734203",
-                "identityPathIndex": [
-                    1,
-                    1,
-                    1,
-                    0,
-                    1,
-                    0,
-                    1,
-                    0,
-                    1,
-                    0,
-                    1,
-                    0,
-                    0,
-                    0,
-                    0,
-                    0,
-                    1,
-                    1,
-                    1,
-                    0
-                ],
-                "identitySecret": "2301650865650889795878889082892690584512243988708213561328369865554257051708",
-                "messageId": "1",
-                "pathElements": [
-                    "14082964758224722211945379872337797638951236517417253447686770846170014042825",
-                    "6628418579821163687428454604867534487917867918886059133241840211975892987309",
-                    "12745863228198753394445659605634840709296716381893463421165313830643281758511",
-                    "56118267389743063830320351452083247040583061493621478539311100137113963555",
-                    "3648731943306935051357703221473866306053186513730785325303257057776816073765",
-                    "10548621390442503192989374711060717107954536293658152583621924810330521179016",
-                    "11741160669079729961275351458682156164905457324981803454515784688429276743441",
-                    "17165464309215350864730477596846156251863702878546777829650812432906796008534",
-                    "18947162586829418653666557598416458949428989734998924978331450666032720066913",
-                    "8809427088917589399897132358419395928548406347152047718919154153577297139202",
-                    "6261460226929242970747566981077801929281729646713842579109271945192964422300",
-                    "13871468675790284383809887052382100311103716176061564908030808887079542722597",
-                    "10413964486611723004584705484327518190402370933255450052832412709168190985805",
-                    "3978387560092078849178760154060822400741873818692524912249877867958842934383",
-                    "14014915591348694328771517896715085647041518432952027841088176673715002508448",
-                    "17680675606519345547327984724173632294904524423937145835611954334756161077843",
-                    "17107175244885276119916848057745382329169223109661217238296871427531065458152",
-                    "18326186549441826262593357123467931475982067066825042001499291800252145875109",
-                    "7043961192177345916232559778383741091053414803377017307095275172896944935996",
-                    "2807630271073553218355393059254209097448243975722083008310815929736065268921"
-                ],
-                "userMessageLimit": "100",
-                "x": "20645213238265527935869146898028115621427162613172918400241870500502509785943"
-            }
-        "#;
-
     #[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
@@ -82,7 +24,7 @@ mod test {
         // generate merkle tree
         let default_leaf = Fr::from(0);
         let mut tree = PoseidonTree::new(
-            tree_height,
+            TEST_TREE_HEIGHT,
             default_leaf,
             ConfigOf::<PoseidonTree>::default(),
         )
@@ -92,141 +34,49 @@ mod test {
         // We check correct computation of the root
         let root = tree.root();
 
-        if TEST_TREE_HEIGHT == 20 || TEST_TREE_HEIGHT == 32 {
-            assert_eq!(
-                root,
-                BigInt([
-                    4939322235247991215,
-                    5110804094006647505,
-                    4427606543677101242,
-                    910933464535675827
-                ])
-                .into()
-            );
-        }
+        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 == 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);
@@ -235,34 +85,8 @@ mod test {
         assert!(tree.verify(&rate_commitment, &merkle_proof).unwrap());
     }
 
-    #[test]
-    // We test a RLN proof generation and verification
-    fn test_witness_from_json() {
-        // We generate all relevant keys
-        let proving_key = zkey_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let verification_key = vk_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let builder = circom_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-
-        // We compute witness from the json input example
-        let witness_json = WITNESS_JSON_20;
-        let rln_witness = rln_witness_from_json(witness_json).unwrap();
-
-        // Let's generate a zkSNARK proof
-        let proof = generate_proof(builder, &proving_key, &rln_witness).unwrap();
-        let proof_values = proof_values_from_witness(&rln_witness).unwrap();
-
-        // Let's verify the proof
-        let verified = verify_proof(&verification_key, &proof, &proof_values);
-
-        assert!(verified.unwrap());
-    }
-
-    #[test]
-    // We test a RLN proof generation and verification
-    fn test_end_to_end() {
-        let tree_height = TEST_TREE_HEIGHT;
+    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);
@@ -271,7 +95,7 @@ mod test {
         //// generate merkle tree
         let default_leaf = Fr::from(0);
         let mut tree = PoseidonTree::new(
-            tree_height,
+            TEST_TREE_HEIGHT,
             default_leaf,
             ConfigOf::<PoseidonTree>::default(),
         )
@@ -288,7 +112,7 @@ mod test {
         let rln_identifier = hash_to_field(b"test-rln-identifier");
         let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
 
-        let rln_witness: RLNWitnessInput = rln_witness_from_values(
+        rln_witness_from_values(
             identity_secret_hash,
             &merkle_proof,
             x,
@@ -296,17 +120,49 @@ mod test {
             user_message_limit,
             Fr::from(1),
         )
-        .unwrap();
+        .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();
+        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).unwrap();
+        let proof = generate_proof(&proving_key, &rln_witness_deser, &graph_data).unwrap();
+        let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();
 
-        let proof_values = proof_values_from_witness(&rln_witness).unwrap();
+        // Let's verify the proof
+        let verified = verify_proof(&verification_key, &proof, &proof_values);
+
+        assert!(verified.unwrap());
+    }
+
+    #[test]
+    // We test a RLN proof generation and verification
+    fn test_end_to_end() {
+        let rln_witness = get_test_witness();
+        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
+        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
+        assert_eq!(rln_witness_deser, rln_witness);
+
+        // We generate all relevant keys
+        let proving_key = zkey_from_folder();
+        let verification_key = &proving_key.0.vk;
+        let graph_data = graph_from_folder();
+
+        // Let's generate a zkSNARK proof
+        let proof = generate_proof(&proving_key, &rln_witness_deser, &graph_data).unwrap();
+
+        let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();
 
         // Let's verify the proof
         let success = verify_proof(&verification_key, &proof, &proof_values).unwrap();
@@ -316,11 +172,13 @@ 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 witness_json: &str = 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);

rln/tests/public.rs

@@ -1,61 +1,64 @@
 #[cfg(test)]
 mod test {
-    use ark_ff::BigInt;
+    #[cfg(not(feature = "stateless"))]
+    use {
+        ark_ff::BigInt,
+        rln::{circuit::TEST_TREE_HEIGHT, protocol::compute_tree_root},
+    };
+
     use ark_std::{rand::thread_rng, UniformRand};
     use rand::Rng;
-    use rln::circuit::{Fr, TEST_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()]);
 
+        // 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 == 20 {
-            assert_eq!(
-                root,
-                Fr::from(BigInt([
-                    17110646155607829651,
-                    5040045984242729823,
-                    6965416728592533086,
-                    2328960363755461975
-                ]))
-            );
-        } else if TEST_TREE_HEIGHT == 32 {
-            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());
@@ -66,126 +69,60 @@ 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 == 20 || TEST_TREE_HEIGHT == 32 {
-            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(
             &identity_secret_hash,

utils/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "zerokit_utils"
-version = "0.4.3"
+version = "0.5.2"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Various utilities for Zerokit"
@@ -12,19 +12,23 @@ repository = "https://github.com/vacp2p/zerokit"
 bench = false
 
 [dependencies]
-ark-ff = { version = "=0.4.1", default-features = false, features = ["asm"] }
-num-bigint = { version = "=0.4.3", default-features = false, features = ["rand"] }
-color-eyre = "=0.6.2"
-pmtree = { package = "pmtree", version = "=2.0.0", optional = true}
-sled = "=0.34.7"
-serde = "=1.0.163"
+ark-ff = { version = "0.5.0", features = ["asm"] }
+num-bigint = { version = "0.4.6", default-features = false, features = [
+    "rand",
+] }
+color-eyre = "0.6.2"
+pmtree = { package = "vacp2p_pmtree", version = "=2.0.2", optional = true }
+sled = "0.34.7"
+serde = "1.0"
+lazy_static = "1.4.0"
+hex = "0.4"
 
 [dev-dependencies]
-ark-bn254 = "=0.4.0"
-num-traits = "=0.2.15"
-hex-literal = "=0.3.4"
-tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
-criterion = { version = "=0.4.0", features = ["html_reports"] }
+ark-bn254 = { version = "0.5.0", features = ["std"] }
+num-traits = "0.2.19"
+hex-literal = "0.3.4"
+tiny-keccak = { version = "2.0.2", features = ["keccak"] }
+criterion = { version = "0.4.0", features = ["html_reports"] }
 
 [features]
 default = ["parallel"]

utils/README.md

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

utils/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 +75,7 @@ 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, [0, 1, 2, 3]).unwrap();
         })
     });
 
@@ -67,22 +90,28 @@ 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 +123,7 @@ 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, [0, 1, 2, 3]).unwrap();
         })
     });
 
@@ -109,6 +138,19 @@ 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!(

utils/src/merkle_tree/full_merkle_tree.rs

@@ -8,7 +8,7 @@ use std::{
 };
 
 ////////////////////////////////////////////////////////////
-/// Full Merkle Tree Implementation
+///// Full Merkle Tree Implementation
 ////////////////////////////////////////////////////////////
 
 /// Merkle tree with all leaf and intermediate hashes stored
@@ -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,
@@ -96,6 +100,7 @@ where
             depth,
             cached_nodes,
             nodes,
+            cached_leaves_indices: vec![0; 1 << depth],
             next_index,
             metadata: Vec::new(),
         })
@@ -116,7 +121,7 @@ where
     }
 
     // Returns the total number of leaves set
-    fn leaves_set(&mut self) -> usize {
+    fn leaves_set(&self) -> usize {
         self.next_index
     }
 
@@ -141,6 +146,42 @@ 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 +199,7 @@ 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 +209,36 @@ 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)
+            .map_err(|e| Report::msg(e.to_string()))
     }
 
     // Sets a leaf at the next available index
@@ -211,11 +252,12 @@ 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"));

utils/src/merkle_tree/merkle_tree.rs

@@ -21,7 +21,7 @@ use color_eyre::Result;
 /// and the hash function used to initialize a Merkle Tree implementation
 pub trait Hasher {
     /// Type of the leaf and tree node
-    type Fr: Clone + Copy + Eq;
+    type Fr: Clone + Copy + Eq + Default + std::fmt::Debug + std::fmt::Display + FromStr;
 
     /// Returns the default tree leaf
     fn default_leaf() -> Self::Fr;
@@ -47,14 +47,16 @@ pub trait ZerokitMerkleTree {
         Self: Sized;
     fn depth(&self) -> usize;
     fn capacity(&self) -> usize;
-    fn leaves_set(&mut self) -> usize;
+    fn leaves_set(&self) -> usize;
     fn root(&self) -> FrOf<Self::Hasher>;
     fn compute_root(&mut self) -> Result<FrOf<Self::Hasher>>;
+    fn get_subtree_root(&self, n: usize, index: usize) -> Result<FrOf<Self::Hasher>>;
     fn set(&mut self, index: usize, leaf: FrOf<Self::Hasher>) -> Result<()>;
     fn set_range<I>(&mut self, start: usize, leaves: I) -> Result<()>
     where
         I: IntoIterator<Item = FrOf<Self::Hasher>>;
     fn get(&self, index: usize) -> Result<FrOf<Self::Hasher>>;
+    fn get_empty_leaves_indices(&self) -> Vec<usize>;
     fn override_range<I, J>(&mut self, start: usize, leaves: I, to_remove_indices: J) -> Result<()>
     where
         I: IntoIterator<Item = FrOf<Self::Hasher>>,

utils/src/merkle_tree/optimal_merkle_tree.rs

@@ -6,7 +6,7 @@ use std::str::FromStr;
 use std::{cmp::max, fmt::Debug};
 
 ////////////////////////////////////////////////////////////
-/// Optimal Merkle Tree Implementation
+///// Optimal Merkle Tree Implementation
 ////////////////////////////////////////////////////////////
 
 /// The Merkle tree structure
@@ -27,6 +27,10 @@ where
     /// The tree nodes
     nodes: HashMap<(usize, usize), 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,
@@ -51,7 +55,9 @@ impl FromStr for OptimalMerkleConfig {
     }
 }
 
-/// Implementations
+////////////////////////////////////////////////////////////
+///// Implementations
+////////////////////////////////////////////////////////////
 
 impl<H: Hasher> ZerokitMerkleTree for OptimalMerkleTree<H>
 where
@@ -78,6 +84,7 @@ where
             cached_nodes: cached_nodes.clone(),
             depth,
             nodes: HashMap::new(),
+            cached_leaves_indices: vec![0; 1 << depth],
             next_index: 0,
             metadata: Vec::new(),
         })
@@ -98,7 +105,7 @@ where
     }
 
     // Returns the total number of leaves set
-    fn leaves_set(&mut self) -> usize {
+    fn leaves_set(&self) -> usize {
         self.next_index
     }
 
@@ -108,6 +115,22 @@ where
         self.get_node(0, 0)
     }
 
+    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 {
+            Ok(self.get_node(n, index >> (self.depth - n)))
+        }
+    }
+
     // Sets a leaf at the specified tree index
     fn set(&mut self, index: usize, leaf: H::Fr) -> Result<()> {
         if index >= self.capacity() {
@@ -116,6 +139,7 @@ where
         self.nodes.insert((self.depth, index), leaf);
         self.recalculate_from(index)?;
         self.next_index = max(self.next_index, index + 1);
+        self.cached_leaves_indices[index] = 1;
         Ok(())
     }
 
@@ -127,6 +151,16 @@ where
         Ok(self.get_node(self.depth, index))
     }
 
+    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 multiple leaves from the specified tree index
     fn set_range<I: IntoIterator<Item = H::Fr>>(&mut self, start: usize, leaves: I) -> Result<()> {
         let leaves = leaves.into_iter().collect::<Vec<_>>();
@@ -136,40 +170,43 @@ where
         }
         for (i, leaf) in leaves.iter().enumerate() {
             self.nodes.insert((self.depth, start + i), *leaf);
+            self.cached_leaves_indices[start + i] = 1;
             self.recalculate_from(start + i)?;
         }
         self.next_index = max(self.next_index, start + leaves.len());
         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 leaves = leaves.into_iter().collect::<Vec<_>>();
-        let to_remove_indices = to_remove_indices.into_iter().collect::<Vec<_>>();
-        // check if the range is valid
-        if leaves.len() + start - to_remove_indices.len() > self.capacity() {
-            return Err(Report::msg("provided range exceeds set size"));
+        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_leaf(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];
         }
 
-        // add leaves
-        for (i, leaf) in leaves.iter().enumerate() {
-            self.nodes.insert((self.depth, start + i), *leaf);
-            self.recalculate_from(start + i)?;
+        for i in indices {
+            self.cached_leaves_indices[i] = 0;
         }
 
-        self.next_index = max(
-            self.next_index,
-            start + leaves.len() - to_remove_indices.len(),
-        );
-        Ok(())
+        self.set_range(start, set_values)
+            .map_err(|e| Report::msg(e.to_string()))
     }
 
     // Sets a leaf at the next available index
@@ -183,11 +220,12 @@ 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, index: usize) -> Result<Self::Proof> {
         if index >= self.capacity() {
             return Err(Report::msg("index exceeds set size"));
@@ -266,6 +304,7 @@ where
             i >>= 1;
             depth -= 1;
             self.nodes.insert((depth, i), h);
+            self.cached_leaves_indices[index] = 1;
             if depth == 0 {
                 break;
             }

utils/tests/merkle_tree.rs

@@ -1,7 +1,8 @@
 // Tests adapted from https://github.com/worldcoin/semaphore-rs/blob/d462a4372f1fd9c27610f2acfe4841fab1d396aa/src/merkle_tree.rs
 #[cfg(test)]
-mod test {
+pub mod test {
     use hex_literal::hex;
+    use std::{fmt::Display, str::FromStr};
     use tiny_keccak::{Hasher as _, Keccak};
     use zerokit_utils::{
         FullMerkleConfig, FullMerkleTree, Hasher, OptimalMerkleConfig, OptimalMerkleTree,
@@ -10,74 +11,257 @@ mod test {
     #[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)
         }
     }
 
+    impl Display for TestFr {
+        fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+            write!(f, "{}", hex::encode(self.0.as_slice()))
+        }
+    }
+
+    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()))
+        }
+    }
+
+    impl From<u32> for TestFr {
+        fn from(value: u32) -> Self {
+            let mut bytes: Vec<u8> = vec![0; 28];
+            bytes.extend_from_slice(&value.to_be_bytes());
+            TestFr(bytes.as_slice().try_into().unwrap())
+        }
+    }
+
+    const DEFAULT_DEPTH: usize = 2;
+
+    fn default_full_merkle_tree(depth: usize) -> FullMerkleTree<Keccak256> {
+        FullMerkleTree::<Keccak256>::new(depth, TestFr([0; 32]), FullMerkleConfig::default())
+            .unwrap()
+    }
+
+    fn default_optimal_merkle_tree(depth: usize) -> OptimalMerkleTree<Keccak256> {
+        OptimalMerkleTree::<Keccak256>::new(depth, TestFr([0; 32]), OptimalMerkleConfig::default())
+            .unwrap()
+    }
+
     #[test]
     fn test_root() {
-        let leaves = [
-            hex!("0000000000000000000000000000000000000000000000000000000000000001"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000002"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000003"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-        ];
-
-        let default_tree_root =
-            hex!("b4c11951957c6f8f642c4af61cd6b24640fec6dc7fc607ee8206a99e92410d30");
+        let default_tree_root = TestFr(hex!(
+            "b4c11951957c6f8f642c4af61cd6b24640fec6dc7fc607ee8206a99e92410d30"
+        ));
 
         let roots = [
             hex!("c1ba1812ff680ce84c1d5b4f1087eeb08147a4d510f3496b2849df3a73f5af95"),
             hex!("893760ec5b5bee236f29e85aef64f17139c3c1b7ff24ce64eb6315fca0f2485b"),
             hex!("222ff5e0b5877792c2bc1670e2ccd0c2c97cd7bb1672a57d598db05092d3d72c"),
             hex!("a9bb8c3f1f12e9aa903a50c47f314b57610a3ab32f2d463293f58836def38d36"),
-        ];
+        ]
+        .map(TestFr);
 
-        let mut tree =
-            FullMerkleTree::<Keccak256>::new(2, [0; 32], FullMerkleConfig::default()).unwrap();
+        let nof_leaves = 4;
+        let leaves: Vec<TestFr> = (1..=nof_leaves as u32).map(TestFr::from).collect();
+
+        let mut tree = default_full_merkle_tree(DEFAULT_DEPTH);
         assert_eq!(tree.root(), default_tree_root);
-        for i in 0..leaves.len() {
+        for i in 0..nof_leaves {
             tree.set(i, leaves[i]).unwrap();
             assert_eq!(tree.root(), roots[i]);
         }
 
-        let mut tree =
-            OptimalMerkleTree::<Keccak256>::new(2, [0; 32], OptimalMerkleConfig::default())
-                .unwrap();
+        let mut tree = default_optimal_merkle_tree(DEFAULT_DEPTH);
         assert_eq!(tree.root(), default_tree_root);
-        for i in 0..leaves.len() {
+        for i in 0..nof_leaves {
             tree.set(i, leaves[i]).unwrap();
             assert_eq!(tree.root(), roots[i]);
         }
     }
 
+    #[test]
+    fn test_get_empty_leaves_indices() {
+        let depth = 4;
+        let nof_leaves: usize = 1 << (depth - 1);
+        let leaves: Vec<TestFr> = (0..nof_leaves as u32).map(TestFr::from).collect();
+        let leaves_2: Vec<TestFr> = (0u32..2).map(TestFr::from).collect();
+        let leaves_4: Vec<TestFr> = (0u32..4).map(TestFr::from).collect();
+
+        let mut tree_full = default_full_merkle_tree(depth);
+        let _ = tree_full.set_range(0, leaves.clone());
+        assert!(tree_full.get_empty_leaves_indices().is_empty());
+
+        let mut vec_idxs = Vec::new();
+        for i in 0..nof_leaves {
+            vec_idxs.push(i);
+            let _ = tree_full.delete(i);
+            assert_eq!(tree_full.get_empty_leaves_indices(), vec_idxs);
+        }
+
+        for i in (0..nof_leaves).rev() {
+            vec_idxs.pop();
+            let _ = tree_full.set(i, leaves[i]);
+            assert_eq!(tree_full.get_empty_leaves_indices(), vec_idxs);
+        }
+
+        // Check situation when the number of items to insert is less than the number of items to delete
+        tree_full
+            .override_range(0, leaves_2.clone(), [0, 1, 2, 3])
+            .unwrap();
+
+        // check if the indexes for write and delete are the same
+        tree_full
+            .override_range(0, leaves_4.clone(), [0, 1, 2, 3])
+            .unwrap();
+        assert_eq!(tree_full.get_empty_leaves_indices(), vec![]);
+
+        // check if indexes for deletion are before indexes for overwriting
+        tree_full
+            .override_range(4, leaves_4.clone(), [0, 1, 2, 3])
+            .unwrap();
+        assert_eq!(tree_full.get_empty_leaves_indices(), vec![0, 1, 2, 3]);
+
+        // check if the indices for write and delete do not overlap completely
+        tree_full
+            .override_range(2, leaves_4.clone(), [0, 1, 2, 3])
+            .unwrap();
+        assert_eq!(tree_full.get_empty_leaves_indices(), vec![0, 1]);
+
+        //// Optimal Merkle Tree Trest
+
+        let mut tree_opt = default_optimal_merkle_tree(depth);
+        let _ = tree_opt.set_range(0, leaves.clone());
+        assert!(tree_opt.get_empty_leaves_indices().is_empty());
+
+        let mut vec_idxs = Vec::new();
+        for i in 0..nof_leaves {
+            vec_idxs.push(i);
+            let _ = tree_opt.delete(i);
+            assert_eq!(tree_opt.get_empty_leaves_indices(), vec_idxs);
+        }
+        for i in (0..nof_leaves).rev() {
+            vec_idxs.pop();
+            let _ = tree_opt.set(i, leaves[i]);
+            assert_eq!(tree_opt.get_empty_leaves_indices(), vec_idxs);
+        }
+
+        // Check situation when the number of items to insert is less than the number of items to delete
+        tree_opt
+            .override_range(0, leaves_2.clone(), [0, 1, 2, 3])
+            .unwrap();
+
+        // check if the indexes for write and delete are the same
+        tree_opt
+            .override_range(0, leaves_4.clone(), [0, 1, 2, 3])
+            .unwrap();
+        assert_eq!(tree_opt.get_empty_leaves_indices(), vec![]);
+
+        // check if indexes for deletion are before indexes for overwriting
+        tree_opt
+            .override_range(4, leaves_4.clone(), [0, 1, 2, 3])
+            .unwrap();
+        assert_eq!(tree_opt.get_empty_leaves_indices(), vec![0, 1, 2, 3]);
+
+        // check if the indices for write and delete do not overlap completely
+        tree_opt
+            .override_range(2, leaves_4.clone(), [0, 1, 2, 3])
+            .unwrap();
+        assert_eq!(tree_opt.get_empty_leaves_indices(), vec![0, 1]);
+    }
+
+    #[test]
+    fn test_subtree_root() {
+        let depth = 3;
+        let nof_leaves: usize = 6;
+        let leaves: Vec<TestFr> = (0..nof_leaves as u32).map(TestFr::from).collect();
+
+        let mut tree_full = default_optimal_merkle_tree(depth);
+        let _ = tree_full.set_range(0, leaves.iter().cloned());
+
+        for i in 0..nof_leaves {
+            // check leaves
+            assert_eq!(
+                tree_full.get(i).unwrap(),
+                tree_full.get_subtree_root(depth, i).unwrap()
+            );
+
+            // check root
+            assert_eq!(tree_full.root(), tree_full.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_full.get_subtree_root(n, idx_l).unwrap();
+                let prev_r = tree_full.get_subtree_root(n, idx_r).unwrap();
+                let subroot = tree_full.get_subtree_root(n - 1, idx_sr).unwrap();
+
+                // check intermediate nodes
+                assert_eq!(Keccak256::hash(&[prev_l, prev_r]), subroot);
+            }
+        }
+
+        let mut tree_opt = default_full_merkle_tree(depth);
+        let _ = tree_opt.set_range(0, leaves.iter().cloned());
+
+        for i in 0..nof_leaves {
+            // check leaves
+            assert_eq!(
+                tree_opt.get(i).unwrap(),
+                tree_opt.get_subtree_root(depth, i).unwrap()
+            );
+            // check root
+            assert_eq!(tree_opt.root(), tree_opt.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_opt.get_subtree_root(n, idx_l).unwrap();
+                let prev_r = tree_opt.get_subtree_root(n, idx_r).unwrap();
+                let subroot = tree_opt.get_subtree_root(n - 1, idx_sr).unwrap();
+
+                // check intermediate nodes
+                assert_eq!(Keccak256::hash(&[prev_l, prev_r]), subroot);
+            }
+        }
+    }
+
     #[test]
     fn test_proof() {
-        let leaves = [
-            hex!("0000000000000000000000000000000000000000000000000000000000000001"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000002"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000003"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-        ];
+        let nof_leaves = 4;
+        let leaves: Vec<TestFr> = (0..nof_leaves as u32).map(TestFr::from).collect();
 
         // We thest the FullMerkleTree implementation
-        let mut tree =
-            FullMerkleTree::<Keccak256>::new(2, [0; 32], FullMerkleConfig::default()).unwrap();
-        for i in 0..leaves.len() {
+        let mut tree = default_full_merkle_tree(DEFAULT_DEPTH);
+        for i in 0..nof_leaves {
             // We set the leaves
             tree.set(i, leaves[i]).unwrap();
 
@@ -94,16 +278,12 @@ mod test {
             assert_eq!(proof.compute_root_from(&leaves[i]), tree.root());
 
             // We check that the proof is not valid for another leaf
-            assert!(!tree
-                .verify(&leaves[(i + 1) % leaves.len()], &proof)
-                .unwrap());
+            assert!(!tree.verify(&leaves[(i + 1) % nof_leaves], &proof).unwrap());
         }
 
         // We test the OptimalMerkleTree implementation
-        let mut tree =
-            OptimalMerkleTree::<Keccak256>::new(2, [0; 32], OptimalMerkleConfig::default())
-                .unwrap();
-        for i in 0..leaves.len() {
+        let mut tree = default_optimal_merkle_tree(DEFAULT_DEPTH);
+        for i in 0..nof_leaves {
             // We set the leaves
             tree.set(i, leaves[i]).unwrap();
 
@@ -120,32 +300,25 @@ mod test {
             assert_eq!(proof.compute_root_from(&leaves[i]), tree.root());
 
             // We check that the proof is not valid for another leaf
-            assert!(!tree
-                .verify(&leaves[(i + 1) % leaves.len()], &proof)
-                .unwrap());
+            assert!(!tree.verify(&leaves[(i + 1) % nof_leaves], &proof).unwrap());
         }
     }
 
     #[test]
     fn test_override_range() {
-        let initial_leaves = [
-            hex!("0000000000000000000000000000000000000000000000000000000000000001"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000002"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000003"),
-            hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-        ];
+        let nof_leaves = 4;
+        let leaves: Vec<TestFr> = (0..nof_leaves as u32).map(TestFr::from).collect();
 
-        let mut tree =
-            OptimalMerkleTree::<Keccak256>::new(2, [0; 32], OptimalMerkleConfig::default())
-                .unwrap();
+        let mut tree = default_optimal_merkle_tree(DEFAULT_DEPTH);
 
         // We set the leaves
-        tree.set_range(0, initial_leaves.iter().cloned()).unwrap();
+        tree.set_range(0, leaves.iter().cloned()).unwrap();
 
         let new_leaves = [
             hex!("0000000000000000000000000000000000000000000000000000000000000005"),
             hex!("0000000000000000000000000000000000000000000000000000000000000006"),
-        ];
+        ]
+        .map(TestFr);
 
         let to_delete_indices: [usize; 2] = [0, 1];
 
@@ -158,8 +331,8 @@ mod test {
         .unwrap();
 
         // ensure that the leaves are set correctly
-        for i in 0..new_leaves.len() {
-            assert_eq!(tree.get_leaf(i), new_leaves[i]);
+        for (i, &new_leaf) in new_leaves.iter().enumerate() {
+            assert_eq!(tree.get_leaf(i), new_leaf);
         }
     }
 }

utils/tests/poseidon_constants.rs

@@ -25,16 +25,10 @@ mod test {
         input_clean = input_clean.trim().to_string();
 
         if radix == 10 {
-            BigUint::from_str_radix(&input_clean, radix)
-                .unwrap()
-                .try_into()
-                .unwrap()
+            BigUint::from_str_radix(&input_clean, radix).unwrap().into()
         } else {
             input_clean = input_clean.replace("0x", "");
-            BigUint::from_str_radix(&input_clean, radix)
-                .unwrap()
-                .try_into()
-                .unwrap()
+            BigUint::from_str_radix(&input_clean, radix).unwrap().into()
         }
     }
     // The following constants were taken from https://github.com/arnaucube/poseidon-rs/blob/233027d6075a637c29ad84a8a44f5653b81f0410/src/constants.rs
@@ -3500,21 +3494,21 @@ mod test {
     fn load_constants() -> (Vec<Vec<Fr>>, Vec<Vec<Vec<Fr>>>) {
         let (c_str, m_str) = constants();
         let mut c: Vec<Vec<Fr>> = Vec::new();
-        for i in 0..c_str.len() {
-            let mut cci: Vec<Fr> = Vec::new();
-            for j in 0..c_str[i].len() {
-                let b: Fr = str_to_fr(c_str[i][j], 10);
-                cci.push(b);
+        for c_i in c_str {
+            let mut ci: Vec<Fr> = Vec::new();
+            for c_i_j in c_i {
+                let b: Fr = str_to_fr(c_i_j, 10);
+                ci.push(b);
             }
-            c.push(cci);
+            c.push(ci);
         }
         let mut m: Vec<Vec<Vec<Fr>>> = Vec::new();
-        for i in 0..m_str.len() {
+        for m_i in m_str {
             let mut mi: Vec<Vec<Fr>> = Vec::new();
-            for j in 0..m_str[i].len() {
+            for m_i_j in m_i {
                 let mut mij: Vec<Fr> = Vec::new();
-                for k in 0..m_str[i][j].len() {
-                    let b: Fr = str_to_fr(m_str[i][j][k], 10);
+                for m_i_j_k in m_i_j {
+                    let b: Fr = str_to_fr(m_i_j_k, 10);
                     mij.push(b);
                 }
                 mi.push(mij);
@@ -3542,7 +3536,7 @@ mod test {
                 assert_eq!(loaded_m[i], poseidon_parameters[i].m);
             }
         } else {
-            assert!(false);
+            unreachable!();
         }
     }
 }