chore: Release

* replace arkzkey submodule to library

* update ci

.github/workflows/ci.yml

@@ -3,27 +3,20 @@ on:
     branches:
       - master
     paths-ignore:
-      - '**.md'
-      - '!.github/workflows/*.yml'
-      - '!multiplier/src/**'
-      - '!private-settlement/src/**'
-      - '!rln-wasm/**'
-      - '!rln/src/**'
-      - '!rln/resources/**'
-      - '!semaphore/src/**'
-      - '!utils/src/**'
+      - "**.md"
+      - "!.github/workflows/*.yml"
+      - "!rln-wasm/**"
+      - "!rln/src/**"
+      - "!rln/resources/**"
+      - "!utils/src/**"
   pull_request:
     paths-ignore:
-      - '**.md'
-      - '!.github/workflows/*.yml'
-      - '!multiplier/src/**'
-      - '!private-settlement/src/**'
-      - '!rln-wasm/**'
-      - '!rln/src/**'
-      - '!rln/resources/**'
-      - '!semaphore/src/**'
-      - '!utils/src/**'
-
+      - "**.md"
+      - "!.github/workflows/*.yml"
+      - "!rln-wasm/**"
+      - "!rln/src/**"
+      - "!rln/resources/**"
+      - "!utils/src/**"
 
 name: Tests
 
@@ -32,10 +25,10 @@ jobs:
     strategy:
       matrix:
         platform: [ubuntu-latest, macos-latest]
-        crate: [multiplier, semaphore, rln, utils]
+        crate: [rln, utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
-  
+
     name: test - ${{ matrix.crate }} - ${{ matrix.platform }}
     steps:
       - name: Checkout sources
@@ -51,16 +44,16 @@ jobs:
         run: make installdeps
       - name: cargo-make test
         run: |
-            cargo make test --release
+          cargo make test --release
         working-directory: ${{ matrix.crate }}
-  
+
   rln-wasm:
     strategy:
       matrix:
         platform: [ubuntu-latest, macos-latest]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
-  
+
     name: test - rln-wasm - ${{ matrix.platform }}
     steps:
       - uses: actions/checkout@v3
@@ -85,11 +78,11 @@ jobs:
       matrix:
         # we run lint tests only on ubuntu
         platform: [ubuntu-latest]
-        crate: [multiplier, semaphore, rln, utils]
+        crate: [rln, utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 
-    name: lint - ${{ matrix.crate }} - ${{ matrix.platform }}  
+    name: lint - ${{ matrix.crate }} - ${{ matrix.platform }}
     steps:
       - name: Checkout sources
         uses: actions/checkout@v3
@@ -110,7 +103,7 @@ jobs:
       - name: cargo clippy
         if: success() || failure()
         run: |
-            cargo clippy --release -- -D warnings
+          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
@@ -134,4 +127,4 @@ jobs:
       - uses: boa-dev/criterion-compare-action@v3
         with:
           branchName: ${{ github.base_ref }}
-          cwd: ${{ matrix.crate }}
+          cwd: ${{ matrix.crate }}

.github/workflows/nightly-release.yml

@@ -8,7 +8,8 @@ jobs:
   linux:
     strategy:
       matrix:
-        target: 
+        feature: ["default", "arkzkey"]
+        target:
           - x86_64-unknown-linux-gnu
           - aarch64-unknown-linux-gnu
           - i686-unknown-linux-gnu
@@ -29,16 +30,16 @@ 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 ${{ matrix.feature }} --workspace --exclude rln-wasm
           mkdir release
           cp target/${{ 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
         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:
@@ -46,7 +47,8 @@ jobs:
     runs-on: macos-latest
     strategy:
       matrix:
-        target: 
+        feature: ["default", "arkzkey"]
+        target:
           - x86_64-apple-darwin
           - aarch64-apple-darwin
     steps:
@@ -64,18 +66,18 @@ jobs:
         run: make installdeps
       - name: cross build
         run: |
-          cross build --release --target ${{ matrix.target }} --workspace --exclude rln-wasm
+          cross build --release --target ${{ matrix.target }} --features ${{ matrix.feature }} --workspace --exclude rln-wasm
           mkdir release
           cp target/${{ 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
         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
@@ -108,7 +110,6 @@ jobs:
           path: rln-wasm/browser-rln-wasm.tar.gz
           retention-days: 2
 
-
   prepare-prerelease:
     name: Prepare pre-release
     needs: [linux, macos, browser-rln-wasm]
@@ -120,7 +121,7 @@ jobs:
           ref: master
       - name: Download artifacts
         uses: actions/download-artifact@v2
-          
+
       - name: Delete tag
         uses: dev-drprasad/delete-tag-and-release@v0.2.1
         with:

.gitmodules

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

Cargo.toml

@@ -1,13 +1,7 @@
 [workspace]
-members = [
-  "multiplier",
-  "private-settlement",
-  "semaphore",
-  "rln",
-  "rln-cli",
-  "rln-wasm",
-  "utils",
-]
+members = ["rln", "rln-cli", "rln-wasm", "utils"]
+default-members = ["rln", "rln-cli", "utils"]
+resolver = "2"
 
 # Compilation profile for any non-workspace member.
 # Dependencies are optimized, even in a dev build. This improves dev performance
@@ -18,6 +12,3 @@ opt-level = 3
 [profile.release.package."rln-wasm"]
 # Tell `rustc` to optimize for small code size.
 opt-level = "s"
-
-[profile.release.package."semaphore"]
-codegen-units = 1

Cross.toml

@@ -29,4 +29,7 @@ image = "ghcr.io/cross-rs/mips64-unknown-linux-gnuabi64:latest"
 image = "ghcr.io/cross-rs/mips64el-unknown-linux-gnuabi64:latest"
 
 [target.mipsel-unknown-linux-gnu]
-image = "ghcr.io/cross-rs/mipsel-unknown-linux-gnu:latest"
+image = "ghcr.io/cross-rs/mipsel-unknown-linux-gnu:latest"
+
+[target.aarch64-linux-android]
+image = "ghcr.io/cross-rs/aarch64-linux-android:edge"

Makefile

@@ -13,15 +13,19 @@ endif
 
 installdeps: .pre-build
 ifeq ($(shell uname),Darwin)
-# commented due to https://github.com/orgs/Homebrew/discussions/4612	
-# @brew update 
+# commented due to https://github.com/orgs/Homebrew/discussions/4612
+# @brew update
 	@brew install cmake ninja
 else ifeq ($(shell uname),Linux)
 	@sudo apt-get update
 	@sudo apt-get install -y cmake ninja-build
 endif
-	@git clone --recursive https://github.com/WebAssembly/wabt.git
-	@cd wabt && mkdir build && cd build && cmake .. -GNinja && ninja && sudo ninja install
+	@git -C "wabt" pull || git clone --recursive https://github.com/WebAssembly/wabt.git "wabt"
+	@cd wabt && mkdir -p build && cd build && cmake .. -GNinja && ninja && sudo ninja install
+	@which wasm-pack || cargo install wasm-pack
+	# nvm already checks if it's installed, and no-ops if it is
+	@curl -o- https://raw.githubusercontent.com/nvm-sh/nvm/v0.39.7/install.sh | bash
+	@. ${HOME}/.nvm/nvm.sh && nvm install 18.20.2 && nvm use 18.20.2;
 
 build: .pre-build
 	@cargo make build

README.md

@@ -18,13 +18,23 @@ in Rust.
 
 - [semaphore-rs](https://github.com/worldcoin/semaphore-rs) written in Rust based on ark-circom.
 
+## Users
+
+Zerokit is used by -
+
+- [nwaku](https://github.com/waku-org/nwaku)
+- [js-rln](https://github.com/waku-org/js-rln)
+
 ## Build and Test
 
 To install missing dependencies, run the following commands from the root folder
+
 ```bash
 make installdeps
 ```
+
 To build and test all crates, run the following commands from the root folder
+
 ```bash
 make build
 make test
@@ -32,4 +42,4 @@ make test
 
 ## 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 for rln.

multiplier/Cargo.toml

@@ -1,32 +0,0 @@
-[package]
-name = "multiplier"
-version = "0.1.0"
-edition = "2018"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-
-# WASM operations
-# wasmer = { version = "2.0" }
-# fnv = { version = "1.0.3", default-features = false }
-# num = { version = "0.4.0" }
-# num-traits = { version = "0.2.0", default-features = false }
-
-# ZKP Generation
-# ark-ff = { version = "0.3.0", default-features = false, features = ["parallel", "asm"] }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-bn254 = { version = "0.3.0" }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-# ark-poly = { version = "^0.3.0", default-features = false, features = ["parallel"] }
-ark-serialize = { version = "0.3.0", default-features = false }
-
-ark-circom = { git = "https://github.com/gakonst/ark-circom", features = ["circom-2"], rev = "35ce5a9" }
-
-# error handling
-color-eyre = "0.6.1"
-
-# decoding of data
-# hex = "0.4.3"
-# byteorder = "1.4.3"

multiplier/Makefile.toml

@@ -1,7 +0,0 @@
-[tasks.build]
-command = "cargo"
-args = ["build", "--release"]
-
-[tasks.test]
-command = "cargo"
-args = ["test", "--release"]

multiplier/README.md

@@ -1,21 +0,0 @@
-# Multiplier example
-
-Example wrapper around a basic Circom circuit to test Circom 2 integration
-through ark-circom and FFI.
-
-## Build and Test
-
-To build and test, run the following commands within the module folder
-```bash
-cargo make build
-cargo make test
-```
-
-## FFI
-
-To generate C or Nim bindings from Rust FFI, use `cbindgen` or `nbindgen`:
-
-```
-cbindgen . -o target/multiplier.h
-nbindgen . -o target/multiplier.nim
-```

multiplier/src/ffi.rs

@@ -1,77 +0,0 @@
-use crate::public::Multiplier;
-use std::slice;
-
-/// Buffer struct is taken from
-/// https://github.com/celo-org/celo-threshold-bls-rs/blob/master/crates/threshold-bls-ffi/src/ffi.rs
-///
-/// Also heavily inspired by https://github.com/kilic/rln/blob/master/src/ffi.rs
-
-#[repr(C)]
-#[derive(Clone, Debug, PartialEq)]
-pub struct Buffer {
-    pub ptr: *const u8,
-    pub len: usize,
-}
-
-impl From<&[u8]> for Buffer {
-    fn from(src: &[u8]) -> Self {
-        Self {
-            ptr: &src[0] as *const u8,
-            len: src.len(),
-        }
-    }
-}
-
-impl<'a> From<&Buffer> for &'a [u8] {
-    fn from(src: &Buffer) -> &'a [u8] {
-        unsafe { slice::from_raw_parts(src.ptr, src.len) }
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn new_circuit(ctx: *mut *mut Multiplier) -> bool {
-    if let Ok(mul) = Multiplier::new() {
-        unsafe { *ctx = Box::into_raw(Box::new(mul)) };
-        true
-    } else {
-        false
-    }
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn prove(ctx: *const Multiplier, output_buffer: *mut Buffer) -> bool {
-    println!("multiplier ffi: prove");
-    let mul = unsafe { &*ctx };
-    let mut output_data: Vec<u8> = Vec::new();
-
-    match mul.prove(&mut output_data) {
-        Ok(proof_data) => proof_data,
-        Err(_) => return false,
-    };
-    unsafe { *output_buffer = Buffer::from(&output_data[..]) };
-    std::mem::forget(output_data);
-    true
-}
-
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn verify(
-    ctx: *const Multiplier,
-    proof_buffer: *const Buffer,
-    result_ptr: *mut u32,
-) -> bool {
-    println!("multiplier ffi: verify");
-    let mul = unsafe { &*ctx };
-    let proof_data = <&[u8]>::from(unsafe { &*proof_buffer });
-    if match mul.verify(proof_data) {
-        Ok(verified) => verified,
-        Err(_) => return false,
-    } {
-        unsafe { *result_ptr = 0 };
-    } else {
-        unsafe { *result_ptr = 1 };
-    };
-    true
-}

multiplier/src/lib.rs

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

multiplier/src/main.rs

@@ -1,49 +0,0 @@
-use ark_circom::{CircomBuilder, CircomConfig};
-use ark_std::rand::thread_rng;
-use color_eyre::{Report, Result};
-
-use ark_bn254::Bn254;
-use ark_groth16::{
-    create_random_proof as prove, generate_random_parameters, prepare_verifying_key, verify_proof,
-};
-
-fn groth16_proof_example() -> Result<()> {
-    let cfg = CircomConfig::<Bn254>::new(
-        "./resources/circom2_multiplier2.wasm",
-        "./resources/circom2_multiplier2.r1cs",
-    )?;
-
-    let mut builder = CircomBuilder::new(cfg);
-    builder.push_input("a", 3);
-    builder.push_input("b", 11);
-
-    // create an empty instance for setting it up
-    let circom = builder.setup();
-
-    let mut rng = thread_rng();
-    let params = generate_random_parameters::<Bn254, _, _>(circom, &mut rng)?;
-
-    let circom = builder.build()?;
-
-    let inputs = circom
-        .get_public_inputs()
-        .ok_or(Report::msg("no public inputs"))?;
-
-    let proof = prove(circom, &params, &mut rng)?;
-
-    let pvk = prepare_verifying_key(&params.vk);
-
-    match verify_proof(&pvk, &proof, &inputs) {
-        Ok(_) => Ok(()),
-        Err(_) => Err(Report::msg("not verified")),
-    }
-}
-
-fn main() {
-    println!("Hello, world!");
-
-    match groth16_proof_example() {
-        Ok(_) => println!("Success"),
-        Err(_) => println!("Error"),
-    }
-}

multiplier/src/public.rs

@@ -1,79 +0,0 @@
-use ark_circom::{CircomBuilder, CircomCircuit, CircomConfig};
-use ark_std::rand::thread_rng;
-
-use ark_bn254::Bn254;
-use ark_groth16::{
-    create_random_proof as prove, generate_random_parameters, prepare_verifying_key, verify_proof,
-    Proof, ProvingKey,
-};
-use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
-use color_eyre::{Report, Result};
-use std::io::{Read, Write};
-
-pub struct Multiplier {
-    circom: CircomCircuit<Bn254>,
-    params: ProvingKey<Bn254>,
-}
-
-impl Multiplier {
-    // TODO Break this apart here
-    pub fn new() -> Result<Multiplier> {
-        let cfg = CircomConfig::<Bn254>::new(
-            "./resources/circom2_multiplier2.wasm",
-            "./resources/circom2_multiplier2.r1cs",
-        )?;
-
-        let mut builder = CircomBuilder::new(cfg);
-        builder.push_input("a", 3);
-        builder.push_input("b", 11);
-
-        // create an empty instance for setting it up
-        let circom = builder.setup();
-
-        let mut rng = thread_rng();
-
-        let params = generate_random_parameters::<Bn254, _, _>(circom, &mut rng)?;
-
-        let circom = builder.build()?;
-
-        Ok(Multiplier { circom, params })
-    }
-
-    // TODO Input Read
-    pub fn prove<W: Write>(&self, result_data: W) -> Result<()> {
-        let mut rng = thread_rng();
-
-        // XXX: There's probably a better way to do this
-        let circom = self.circom.clone();
-        let params = self.params.clone();
-
-        let proof = prove(circom, &params, &mut rng)?;
-
-        // XXX: Unclear if this is different from other serialization(s)
-        proof.serialize(result_data)?;
-
-        Ok(())
-    }
-
-    pub fn verify<R: Read>(&self, input_data: R) -> Result<bool> {
-        let proof = Proof::deserialize(input_data)?;
-
-        let pvk = prepare_verifying_key(&self.params.vk);
-
-        // XXX Part of input data?
-        let inputs = self
-            .circom
-            .get_public_inputs()
-            .ok_or(Report::msg("no public inputs"))?;
-
-        let verified = verify_proof(&pvk, &proof, &inputs)?;
-
-        Ok(verified)
-    }
-}
-
-impl Default for Multiplier {
-    fn default() -> Self {
-        Self::new().unwrap()
-    }
-}

multiplier/tests/public.rs

@@ -1,21 +0,0 @@
-#[cfg(test)]
-mod tests {
-    use multiplier::public::Multiplier;
-
-    #[test]
-    fn multiplier_proof() {
-        let mul = Multiplier::new().unwrap();
-
-        let mut output_data: Vec<u8> = Vec::new();
-        let _ = mul.prove(&mut output_data);
-
-        let proof_data = &output_data[..];
-
-        // XXX Pass as arg?
-        //let pvk = prepare_verifying_key(&mul.params.vk);
-
-        let verified = mul.verify(proof_data).unwrap();
-
-        assert!(verified);
-    }
-}

private-settlement/Cargo.toml

@@ -1,9 +0,0 @@
-[package]
-name = "private-settlement"
-version = "0.1.0"
-edition = "2021"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]

private-settlement/Makefile.toml

@@ -1,7 +0,0 @@
-[tasks.build]
-command = "cargo"
-args = ["build", "--release"]
-
-[tasks.test]
-command = "cargo"
-args = ["test", "--release"]

private-settlement/README.md

@@ -1,11 +0,0 @@
-# Private Settlement  Module
-
-This module is to provide APIs to manage, compute and verify [Private Settlement](https://rfc.vac.dev/spec/44/) zkSNARK proofs and primitives.
-
-## Build and Test
-
-To build and test, run the following commands within the module folder
-```bash
-cargo make build
-cargo make test
-```

private-settlement/src/lib.rs

@@ -1 +0,0 @@
-

private-settlement/tests/private-settlement.rs

@@ -1,11 +0,0 @@
-#[cfg(test)]
-mod tests {
-    #[cfg(test)]
-    mod tests {
-        #[test]
-        fn it_works() {
-            let result = 2 + 2;
-            assert_eq!(result, 4);
-        }
-    }
-}

rln-cli/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rln-cli"
-version = "0.1.0"
+version = "0.3.0"
 edition = "2021"
 
 [dependencies]

rln-cli/src/commands.rs

@@ -15,6 +15,8 @@ pub(crate) enum Commands {
         /// Sets a custom config file
         #[arg(short, long)]
         config: PathBuf,
+        #[arg(short, long)]
+        tree_config_input: PathBuf,
     },
     SetTree {
         tree_height: usize,

rln-cli/src/main.rs

@@ -34,9 +34,14 @@ fn main() -> Result<()> {
         Some(Commands::NewWithParams {
             tree_height,
             config,
+            tree_config_input,
         }) => {
             let mut resources: Vec<Vec<u8>> = Vec::new();
-            for filename in ["rln.wasm", "rln_final.zkey", "verification_key.json"] {
+            #[cfg(feature = "arkzkey")]
+            let filenames = ["rln.wasm", "rln_final.arkzkey", "verification_key.json"];
+            #[cfg(not(feature = "arkzkey"))]
+            let filenames = ["rln.wasm", "rln_final.zkey", "verification_key.json"];
+            for filename in filenames {
                 let fullpath = config.join(Path::new(filename));
                 let mut file = File::open(&fullpath)?;
                 let metadata = std::fs::metadata(&fullpath)?;
@@ -44,11 +49,13 @@ fn main() -> Result<()> {
                 file.read_exact(&mut buffer)?;
                 resources.push(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,
             )?);
             Ok(())
         }

rln-cli/src/state.rs

@@ -2,7 +2,7 @@ use color_eyre::Result;
 use rln::public::RLN;
 use std::fs::File;
 
-use crate::config::{InnerConfig, Config};
+use crate::config::{Config, InnerConfig};
 
 #[derive(Default)]
 pub(crate) struct State<'a> {

rln-wasm/Cargo.toml

@@ -1,8 +1,11 @@
 [package]
 name = "rln-wasm"
-version = "0.0.9"
+version = "0.0.13"
 edition = "2021"
 license = "MIT or Apache2"
+autobenches = false
+autotests = false
+autobins = false
 
 [lib]
 crate-type = ["cdylib", "rlib"]
@@ -30,4 +33,3 @@ 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

@@ -29,3 +29,7 @@ args = ["login"]
 [tasks.publish]
 command = "wasm-pack"
 args = ["publish", "--access", "public", "--target", "web"]
+
+[tasks.bench]
+command = "echo"
+args = ["'No benchmarks available for this project'"]

rln-wasm/src/lib.rs

@@ -250,11 +250,7 @@ pub fn wasm_set_metadata(ctx: *mut RLNWrapper, input: Uint8Array) -> Result<(),
 #[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()
-    )
+    call_with_output_and_error_msg!(ctx, get_metadata, "could not get metadata".to_string())
 }
 
 #[allow(clippy::not_unsafe_ptr_arg_deref)]

rln-wasm/tests/rln-wasm.rs

@@ -3,8 +3,9 @@
 #[cfg(test)]
 mod tests {
     use js_sys::{BigInt as JsBigInt, Object, Uint8Array};
-    use rln::circuit::TEST_TREE_HEIGHT;
-    use rln::utils::normalize_usize;
+    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;
@@ -33,26 +34,40 @@ mod tests {
 
         // Creating membership key
         let mem_keys = wasm_key_gen(rln_instance).unwrap();
-        let idkey = mem_keys.subarray(0, 32);
-        let idcommitment = mem_keys.subarray(32, 64);
-
-        // Insert PK
-        wasm_set_next_leaf(rln_instance, idcommitment).unwrap();
+        let id_key = mem_keys.subarray(0, 32);
+        let id_commitment = mem_keys.subarray(32, 64);
 
         // Prepare the message
-        let signal = "Hello World".as_bytes();
-
-        // Setting up the epoch (With 0s for the test)
-        let epoch = Uint8Array::new_with_length(32);
-        epoch.fill(0, 0, 32);
+        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 idkey.to_vec());
+        serialized_vec.append(&mut id_key.to_vec());
         serialized_vec.append(&mut normalize_usize(identity_index));
-        serialized_vec.append(&mut epoch.to_vec());
+        serialized_vec.append(&mut fr_to_bytes_le(&user_message_limit).to_vec());
+        serialized_vec.append(&mut message_id.to_vec());
+        serialized_vec.append(&mut 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[..]);
@@ -112,7 +127,6 @@ mod tests {
     #[wasm_bindgen_test]
     fn test_metadata() {
         let tree_height = TEST_TREE_HEIGHT;
-        let circom_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln.wasm");
         let zkey_path = format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/rln_final.zkey");
         let vk_path =
             format!("../rln/resources/tree_height_{TEST_TREE_HEIGHT}/verification_key.json");
@@ -122,7 +136,6 @@ mod tests {
         // 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();

rln/Cargo.toml

@@ -1,9 +1,12 @@
 [package]
 name = "rln"
-version = "0.1.0"
+version = "0.5.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
+documentation = "https://github.com/vacp2p/zerokit"
+homepage = "https://vac.dev"
+repository = "https://github.com/vacp2p/zerokit"
 
 [lib]
 crate-type = ["rlib", "staticlib"]
@@ -16,13 +19,20 @@ 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-ff = { version = "=0.4.1", default-features = false, features = ["asm"] }
 ark-std = { version = "=0.4.0", default-features = false }
 ark-bn254 = { version = "=0.4.0" }
-ark-groth16 = { version = "=0.4.0", features = ["parallel"], default-features = false }
-ark-relations = { version = "=0.4.0", default-features = false, features = [ "std" ] }
+ark-groth16 = { version = "=0.4.0", features = [
+    "parallel",
+], default-features = false }
+ark-relations = { version = "=0.4.0", default-features = false, features = [
+    "std",
+] }
 ark-serialize = { version = "=0.4.1", default-features = false }
-ark-circom = { version = "=0.1.0", default-features = false, features = ["circom-2"] }
+ark-circom = { version = "=0.1.0", default-features = false, features = [
+    "circom-2",
+] }
+ark-zkey = { version = "0.1.0", optional = true, default-features = false }
 
 # WASM
 wasmer = { version = "=2.3.0", default-features = false }
@@ -33,13 +43,16 @@ thiserror = "=1.0.39"
 
 # utilities
 cfg-if = "=1.0"
-num-bigint = { version = "=0.4.3", default-features = false, features = ["rand"] }
+num-bigint = { version = "=0.4.3", default-features = false, features = [
+    "rand",
+] }
 num-traits = "=0.2.15"
 once_cell = "=1.17.1"
 rand = "=0.8.5"
 rand_chacha = "=0.3.1"
 tiny-keccak = { version = "=2.0.2", features = ["keccak"] }
-utils = { package = "zerokit_utils", version = "=0.1.0", path = "../utils/", default-features = false }
+utils = { package = "zerokit_utils", version = "=0.5.0", path = "../utils/", default-features = false }
+
 
 # serialization
 serde_json = "=1.0.96"
@@ -53,9 +66,16 @@ criterion = { version = "=0.4.0", features = ["html_reports"] }
 
 [features]
 default = ["parallel", "wasmer/sys-default", "pmtree-ft"]
-parallel = ["ark-ec/parallel", "ark-ff/parallel", "ark-std/parallel", "ark-groth16/parallel", "utils/parallel"]
+parallel = [
+    "ark-ec/parallel",
+    "ark-ff/parallel",
+    "ark-std/parallel",
+    "ark-groth16/parallel",
+    "utils/parallel",
+]
 wasm = ["wasmer/js", "wasmer/std"]
 fullmerkletree = ["default"]
+arkzkey = ["ark-zkey"]
 
 # Note: pmtree feature is still experimental
 pmtree-ft = ["utils/pmtree-ft"]
@@ -63,3 +83,11 @@ pmtree-ft = ["utils/pmtree-ft"]
 [[bench]]
 name = "pmtree_benchmark"
 harness = false
+
+[[bench]]
+name = "circuit_loading_benchmark"
+harness = false
+
+[[bench]]
+name = "poseidon_tree_benchmark"
+harness = false

rln/README.md

@@ -3,6 +3,7 @@
 This module provides APIs to manage, compute and verify [RLN](https://rfc.vac.dev/spec/32/) zkSNARK proofs and RLN primitives.
 
 ## Pre-requisites
+
 ### Install dependencies and clone repo
 
 ```sh
@@ -14,6 +15,7 @@ cd zerokit/rln
 ### Build and Test
 
 To build and test, run the following commands within the module folder
+
 ```bash
 cargo make build
 cargo make test
@@ -21,11 +23,11 @@ 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. 
+The `rln` (https://github.com/rate-limiting-nullifier/circom-rln) repository, which contains the RLN circuit implementation is a submodule of zerokit RLN.
 
 To compile the RLN circuit
 
-``` sh
+```sh
 # Update submodules
 git submodule update --init --recursive
 
@@ -52,11 +54,10 @@ 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`. 
+However, if `N` is too big, this might require a bigger Powers of Tau ceremony than the one hardcoded in `./scripts/build-circuits.sh`, which is `2^14`.
 In such case we refer to the official [Circom documentation](https://docs.circom.io/getting-started/proving-circuits/#powers-of-tau) for instructions on how to run an appropriate Powers of Tau ceremony and Phase 2 in order to compile the desired circuit.
 
-
-Currently, the `rln` module comes with three [pre-compiled](https://github.com/vacp2p/zerokit/tree/master/rln/resources) RLN circuits having Merkle tree of height `15`, `19` and `20`, respectively.
+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
 
@@ -73,7 +74,7 @@ rln = { git = "https://github.com/vacp2p/zerokit" }
 
 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 circuit (`rln.wasm`, built for the input tree size), the corresponding proving key (`rln_final.zkey`) or (`rln_final.arkzkey`) and verification key (`verification_key.json`, optional) are found.
 
 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.
 
@@ -82,14 +83,14 @@ use rln::protocol::*;
 use rln::public::*;
 use std::io::Cursor;
 
-// We set the RLN parameters: 
+// We set the RLN parameters:
 // - the tree height;
-// - the circuit resource folder (requires a trailing "/").
+// - the tree config, if it is not defined, the default value will be set
 let tree_height = 20;
-let resources = Cursor::new("../zerokit/rln/resources/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);
 ```
 
 ### Generate an identity keypair
@@ -102,50 +103,62 @@ let mut buffer = Cursor::new(Vec::<u8>::new());
 rln.key_gen(&mut buffer).unwrap();
 
 // We deserialize the keygen output to obtain
-// the identiy_secret and id_commitment
+// the identity_secret and id_commitment
 let (identity_secret_hash, id_commitment) = deserialize_identity_pair(buffer.into_inner());
 ```
 
-### Add ID commitment to the RLN Merkle tree
+### Add Rate commitment to the RLN Merkle tree
 
 ```rust
 // We define the tree index where id_commitment will be added
 let id_index = 10;
+let user_message_limit = 10;
 
 // We serialize id_commitment and pass it to set_leaf
-let mut buffer = Cursor::new(serialize_field_element(id_commitment));
+let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+let mut buffer = Cursor::new(serialize_field_element(rate_commitment));
 rln.set_leaf(id_index, &mut buffer).unwrap();
 ```
 
 Note that when tree leaves are not explicitly set by the user (in this example, all those with index less and greater than `10`), their values is set to an hardcoded default (all-`0` bytes in current implementation).
 
-### Set epoch
+### Set external nullifier
 
-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.
+The `external nullifier` includes two parameters.
+
+The first one is `epoch` and it's used to identify messages received in a certain time frame. It usually corresponds to the current UNIX time but can also be set to a random value or generated by a seed, provided that it corresponds to a field element.
+
+The second one is `rln_identifier` and it's used to prevent a RLN ZK proof generated for one application to be re-used in another one.
 
 ```rust
 // We generate epoch from a date seed and we ensure is
 // mapped to a field element by hashing-to-field its content
 let epoch = hash_to_field(b"Today at noon, this year");
+// We generate rln_identifier from a date seed and we ensure is
+// mapped to a field element by hashing-to-field its content
+let rln_identifier = hash_to_field(b"test-rln-identifier");
+
+let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
 ```
+
 ### Set signal
 
 The signal is the message for which we are computing a RLN proof.
 
 ```rust
-// We set our signal 
+// We set our signal
 let signal = b"RLN is awesome";
 ```
 
 ### Generate a RLN proof
 
-We prepare the input to the proof generation routine. 
+We prepare the input to the proof generation routine.
 
-Input buffer is serialized as `[ identity_key | id_index | epoch | signal_len | signal ]`.
+Input buffer is serialized as `[ identity_key | id_index | external_nullifier | user_message_limit | message_id | signal_len | signal ]`.
 
 ```rust
 // We prepare input to the proof generation routine
-let proof_input = prepare_prove_input(identity_secret_hash, id_index, epoch, signal);
+let proof_input = prepare_prove_input(identity_secret_hash, id_index, external_nullifier, signal);
 ```
 
 We are now ready to generate a RLN ZK proof along with the _public outputs_ of the ZK circuit evaluation.
@@ -162,12 +175,11 @@ rln.generate_rln_proof(&mut in_buffer, &mut out_buffer)
 let proof_data = out_buffer.into_inner();
 ```
 
-The byte vector `proof_data` is serialized as `[ zk-proof | tree_root | epoch | share_x | share_y | nullifier | rln_identifier ]`.
-
+The byte vector `proof_data` is serialized as `[ zk-proof | tree_root | external_nullifier | share_x | share_y | nullifier ]`.
 
 ### Verify a RLN proof
 
-We prepare the input to the proof verification routine. 
+We prepare the input to the proof verification routine.
 
 Input buffer is serialized as `[proof_data | signal_len | signal ]`, where `proof_data` is (computed as) the output obtained by `generate_rln_proof`.
 
@@ -180,17 +192,21 @@ let mut in_buffer = Cursor::new(verify_data);
 let verified = rln.verify(&mut in_buffer).unwrap();
 ```
 
-We check if the proof verification was successful: 
+We check if the proof verification was successful:
+
 ```rust
 // We ensure the proof is valid
 assert!(verified);
 ```
 
 ## 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.

rln/benches/circuit_loading_benchmark.rs

@@ -0,0 +1,14 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+
+// Depending on the key type (enabled by the `--features arkzkey` flag)
+// the upload speed from the `rln_final.zkey` or `rln_final.arkzkey` file is calculated
+pub fn key_load_benchmark(c: &mut Criterion) {
+    c.bench_function("zkey::upload_from_folder", |b| {
+        b.iter(|| {
+            let _ = rln::circuit::zkey_from_folder();
+        })
+    });
+}
+
+criterion_group!(benches, key_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_15/verification_key.json

@@ -1,119 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 6,
- "vk_alpha_1": [
-  "20124996762962216725442980738609010303800849578410091356605067053491763969391",
-  "9118593021526896828671519912099489027245924097793322973632351264852174143923",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "4693952934005375501364248788849686435240706020501681709396105298107971354382",
-   "14346958885444710485362620645446987998958218205939139994511461437152241966681"
-  ],
-  [
-   "16851772916911573982706166384196538392731905827088356034885868448550849804972",
-   "823612331030938060799959717749043047845343400798220427319188951998582076532"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "1361919643088555407518565462732544232965454074504004321739078395285189557133",
-   "20823246840633598579879223919854294301857184404415306521912631074982696570306"
-  ],
-  [
-   "7088590198103342249937795923142619828109070290720888704402714617857746884833",
-   "8191367139632195506244169264298620546181137131063303219908889318280111188437"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "12608968655665301215455851857466367636344427685631271961542642719683786103711",
-    "9849575605876329747382930567422916152871921500826003490242628251047652318086"
-   ],
-   [
-    "6322029441245076030714726551623552073612922718416871603535535085523083939021",
-    "8700115492541474338049149013125102281865518624059015445617546140629435818912"
-   ],
-   [
-    "10674973475340072635573101639867487770811074181475255667220644196793546640210",
-    "2926286967251299230490668407790788696102889214647256022788211245826267484824"
-   ]
-  ],
-  [
-   [
-    "9660441540778523475944706619139394922744328902833875392144658911530830074820",
-    "19548113127774514328631808547691096362144426239827206966690021428110281506546"
-   ],
-   [
-    "1870837942477655969123169532603615788122896469891695773961478956740992497097",
-    "12536105729661705698805725105036536744930776470051238187456307227425796690780"
-   ],
-   [
-    "21811903352654147452884857281720047789720483752548991551595462057142824037334",
-    "19021616763967199151052893283384285352200445499680068407023236283004353578353"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "17643142412395322664866141827318671249236739056291610144830020671604112279111",
-   "13273439661778801509295280274403992505521239023074387826870538372514206268318",
-   "1"
-  ],
-  [
-   "12325966053136615826793633393742326952102053533176311103856731330114882211366",
-   "6439956820140153832120005353467272867287237423425778281905068783317736451260",
-   "1"
-  ],
-  [
-   "20405310272367450124741832665322768131899487413829191383721623069139009993137",
-   "21336772016824870564600007750206596010566056069977718959140462128560786193566",
-   "1"
-  ],
-  [
-   "4007669092231576644992949839487535590075070172447826102934640178940614212519",
-   "7597503385395289202372182678960254605827199004598882158153019657732525465207",
-   "1"
-  ],
-  [
-   "4545695279389338758267531646940033299700127241196839077811942492841603458462",
-   "6635771967009274882904456432128877995932122611166121203658485990305433499873",
-   "1"
-  ],
-  [
-   "7876954805169515500747828488548350352651069599547377092970620945851311591012",
-   "7571431725691513008054581132582771105743462534789373657638701712901679323321",
-   "1"
-  ],
-  [
-   "5563973122249220346301217166900152021860462617567141574881706390202619333219",
-   "5147729144109676590873823097632042430451708874867871369293332620382492068692",
-   "1"
-  ]
- ]
-}

rln/resources/tree_height_19/verification_key.json

@@ -1,119 +0,0 @@
-{
- "protocol": "groth16",
- "curve": "bn128",
- "nPublic": 6,
- "vk_alpha_1": [
-  "20124996762962216725442980738609010303800849578410091356605067053491763969391",
-  "9118593021526896828671519912099489027245924097793322973632351264852174143923",
-  "1"
- ],
- "vk_beta_2": [
-  [
-   "4693952934005375501364248788849686435240706020501681709396105298107971354382",
-   "14346958885444710485362620645446987998958218205939139994511461437152241966681"
-  ],
-  [
-   "16851772916911573982706166384196538392731905827088356034885868448550849804972",
-   "823612331030938060799959717749043047845343400798220427319188951998582076532"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_gamma_2": [
-  [
-   "10857046999023057135944570762232829481370756359578518086990519993285655852781",
-   "11559732032986387107991004021392285783925812861821192530917403151452391805634"
-  ],
-  [
-   "8495653923123431417604973247489272438418190587263600148770280649306958101930",
-   "4082367875863433681332203403145435568316851327593401208105741076214120093531"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_delta_2": [
-  [
-   "16125279975606773676640811113051624654121459921695914044301154938920321009721",
-   "14844345250267029614093295465313288254479124604567709177260777529651293576873"
-  ],
-  [
-   "20349277326920398483890518242229158117668855310237215044647746783223259766294",
-   "19338776107510040969200058390413661029003750817172740054990168933780935479540"
-  ],
-  [
-   "1",
-   "0"
-  ]
- ],
- "vk_alphabeta_12": [
-  [
-   [
-    "12608968655665301215455851857466367636344427685631271961542642719683786103711",
-    "9849575605876329747382930567422916152871921500826003490242628251047652318086"
-   ],
-   [
-    "6322029441245076030714726551623552073612922718416871603535535085523083939021",
-    "8700115492541474338049149013125102281865518624059015445617546140629435818912"
-   ],
-   [
-    "10674973475340072635573101639867487770811074181475255667220644196793546640210",
-    "2926286967251299230490668407790788696102889214647256022788211245826267484824"
-   ]
-  ],
-  [
-   [
-    "9660441540778523475944706619139394922744328902833875392144658911530830074820",
-    "19548113127774514328631808547691096362144426239827206966690021428110281506546"
-   ],
-   [
-    "1870837942477655969123169532603615788122896469891695773961478956740992497097",
-    "12536105729661705698805725105036536744930776470051238187456307227425796690780"
-   ],
-   [
-    "21811903352654147452884857281720047789720483752548991551595462057142824037334",
-    "19021616763967199151052893283384285352200445499680068407023236283004353578353"
-   ]
-  ]
- ],
- "IC": [
-  [
-   "5645604624116784480262312750033349186912223090668673154853165165224747369512",
-   "5656337658385597582701340925622307146226708710361427687425735166776477641124",
-   "1"
-  ],
-  [
-   "8216930132302312821663833393171053651364962198587857550991047765311607638330",
-   "19934865864074163318938688021560358348660709566570123384268356491416384822148",
-   "1"
-  ],
-  [
-   "11046959016591768534564223076484566731774575511709349452804727872479525392631",
-   "9401797690410912638766111919371607085248054251975419812613989999345815833269",
-   "1"
-  ],
-  [
-   "13216594148914395028254776738842380005944817065680915990743659996725367876414",
-   "11541283802841111343960351782994043892623551381569479006737253908665900144087",
-   "1"
-  ],
-  [
-   "6957074593219251760608960101283708711892008557897337713430173510328411964571",
-   "21673833055087220750009279957462375662312260098732685145862504142183400549467",
-   "1"
-  ],
-  [
-   "20795071270535109448604057031148356571036039566776607847840379441839742201050",
-   "21654952744643117202636583766828639581880877547772465264383291983528268115687",
-   "1"
-  ],
-  [
-   "19143058772755719660075704757531991493801758701561469885274062297246796623789",
-   "3996020163280925980543600106196205910576345230982361007978823537163123181007",
-   "1"
-  ]
- ]
-}

rln/resources/tree_height_20/verification_key.json

@@ -1,20 +1,20 @@
 {
  "protocol": "groth16",
  "curve": "bn128",
- "nPublic": 6,
+ "nPublic": 5,
  "vk_alpha_1": [
-  "20124996762962216725442980738609010303800849578410091356605067053491763969391",
-  "9118593021526896828671519912099489027245924097793322973632351264852174143923",
+  "20491192805390485299153009773594534940189261866228447918068658471970481763042",
+  "9383485363053290200918347156157836566562967994039712273449902621266178545958",
   "1"
  ],
  "vk_beta_2": [
   [
-   "4693952934005375501364248788849686435240706020501681709396105298107971354382",
-   "14346958885444710485362620645446987998958218205939139994511461437152241966681"
+   "6375614351688725206403948262868962793625744043794305715222011528459656738731",
+   "4252822878758300859123897981450591353533073413197771768651442665752259397132"
   ],
   [
-   "16851772916911573982706166384196538392731905827088356034885868448550849804972",
-   "823612331030938060799959717749043047845343400798220427319188951998582076532"
+   "10505242626370262277552901082094356697409835680220590971873171140371331206856",
+   "21847035105528745403288232691147584728191162732299865338377159692350059136679"
   ],
   [
    "1",
@@ -37,12 +37,12 @@
  ],
  "vk_delta_2": [
   [
-   "8353516066399360694538747105302262515182301251524941126222712285088022964076",
-   "9329524012539638256356482961742014315122377605267454801030953882967973561832"
+   "17077735495685170943380938230836408503627170115414840315502244846025577589191",
+   "14030085636943255545683322474441991939484590437387381169642530788494152024614"
   ],
   [
-   "16805391589556134376869247619848130874761233086443465978238468412168162326401",
-   "10111259694977636294287802909665108497237922060047080343914303287629927847739"
+   "11568745146423307387256571230823432454624378106569286849514884592874522611163",
+   "1838524899938769516485895655063198583192139511330418290063560641219523306282"
   ],
   [
    "1",
@@ -52,67 +52,62 @@
  "vk_alphabeta_12": [
   [
    [
-    "12608968655665301215455851857466367636344427685631271961542642719683786103711",
-    "9849575605876329747382930567422916152871921500826003490242628251047652318086"
+    "2029413683389138792403550203267699914886160938906632433982220835551125967885",
+    "21072700047562757817161031222997517981543347628379360635925549008442030252106"
    ],
    [
-    "6322029441245076030714726551623552073612922718416871603535535085523083939021",
-    "8700115492541474338049149013125102281865518624059015445617546140629435818912"
+    "5940354580057074848093997050200682056184807770593307860589430076672439820312",
+    "12156638873931618554171829126792193045421052652279363021382169897324752428276"
    ],
    [
-    "10674973475340072635573101639867487770811074181475255667220644196793546640210",
-    "2926286967251299230490668407790788696102889214647256022788211245826267484824"
+    "7898200236362823042373859371574133993780991612861777490112507062703164551277",
+    "7074218545237549455313236346927434013100842096812539264420499035217050630853"
    ]
   ],
   [
    [
-    "9660441540778523475944706619139394922744328902833875392144658911530830074820",
-    "19548113127774514328631808547691096362144426239827206966690021428110281506546"
+    "7077479683546002997211712695946002074877511277312570035766170199895071832130",
+    "10093483419865920389913245021038182291233451549023025229112148274109565435465"
    ],
    [
-    "1870837942477655969123169532603615788122896469891695773961478956740992497097",
-    "12536105729661705698805725105036536744930776470051238187456307227425796690780"
+    "4595479056700221319381530156280926371456704509942304414423590385166031118820",
+    "19831328484489333784475432780421641293929726139240675179672856274388269393268"
    ],
    [
-    "21811903352654147452884857281720047789720483752548991551595462057142824037334",
-    "19021616763967199151052893283384285352200445499680068407023236283004353578353"
+    "11934129596455521040620786944827826205713621633706285934057045369193958244500",
+    "8037395052364110730298837004334506829870972346962140206007064471173334027475"
    ]
   ]
  ],
  "IC": [
   [
-   "11992897507809711711025355300535923222599547639134311050809253678876341466909",
-   "17181525095924075896332561978747020491074338784673526378866503154966799128110",
+   "4920513730204767532050733107749276406754520419375654722016092399980613788208",
+   "10950491564509418434657706642388934308456795265036074733953533582377584967294",
    "1"
   ],
   [
-   "17018665030246167677911144513385572506766200776123272044534328594850561667818",
-   "18601114175490465275436712413925513066546725461375425769709566180981674884464",
+   "6815064660695497986531118446154820702646540722664044216580897159556261271171",
+   "17838140936832571103329556013529166877877534025488014783346458943575275015438",
    "1"
   ],
   [
-   "18799470100699658367834559797874857804183288553462108031963980039244731716542",
-   "13064227487174191981628537974951887429496059857753101852163607049188825592007",
+   "16364982450206976302246609763791333525052810246590359380676749324389440643932",
+   "17092624338100676284548565502349491320314889021833923882585524649862570629227",
    "1"
   ],
   [
-   "17432501889058124609368103715904104425610382063762621017593209214189134571156",
-   "13406815149699834788256141097399354592751313348962590382887503595131085938635",
+   "3679639231485547795420532910726924727560917141402837495597760107842698404034",
+   "16213191511474848247596810551723578773353083440353745908057321946068926848382",
    "1"
   ],
   [
-   "10320964835612716439094703312987075811498239445882526576970512041988148264481",
-   "9024164961646353611176283204118089412001502110138072989569118393359029324867",
+   "9215428431027260354679105025212521481930206886203677270216204485256690813172",
+   "934602510541226149881779979217731465262250233587980565969044391353665291792",
    "1"
   ],
   [
-   "718355081067365548229685160476620267257521491773976402837645005858953849298",
-   "14635482993933988261008156660773180150752190597753512086153001683711587601974",
-   "1"
-  ],
-  [
-   "11777720285956632126519898515392071627539405001940313098390150593689568177535",
-   "8483603647274280691250972408211651407952870456587066148445913156086740744515",
+   "8935861545794299876685457331391349387048184820319250771243971382360441890897",
+   "4993459033694759724715904486381952906869986989682015547152342336961693234616",
    "1"
   ]
  ]

rln/src/circuit.rs

@@ -4,14 +4,12 @@ use ark_bn254::{
     Bn254, Fq as ArkFq, Fq2 as ArkFq2, Fr as ArkFr, G1Affine as ArkG1Affine,
     G1Projective as ArkG1Projective, G2Affine as ArkG2Affine, G2Projective as ArkG2Projective,
 };
-use ark_circom::read_zkey;
 use ark_groth16::{ProvingKey, VerifyingKey};
 use ark_relations::r1cs::ConstraintMatrices;
 use cfg_if::cfg_if;
 use color_eyre::{Report, Result};
 use num_bigint::BigUint;
 use serde_json::Value;
-use std::io::Cursor;
 use std::str::FromStr;
 
 cfg_if! {
@@ -25,17 +23,22 @@ cfg_if! {
     }
 }
 
-const ZKEY_FILENAME: &str = "rln_final.zkey";
-const VK_FILENAME: &str = "verification_key.json";
-const WASM_FILENAME: &str = "rln.wasm";
+cfg_if! {
+    if #[cfg(feature = "arkzkey")] {
+        use ark_zkey::read_arkzkey_from_bytes;
+        const ARKZKEY_FILENAME: &str = "tree_height_20/rln_final.arkzkey";
 
-// These parameters are used for tests
-// Note that the circuit and keys in TEST_RESOURCES_FOLDER are compiled for Merkle trees of height 15, 19 and 20
-// Changing these parameters to other values than these defaults will cause zkSNARK proof verification to fail
-pub const TEST_PARAMETERS_INDEX: usize = 2;
-pub const TEST_TREE_HEIGHT: usize = [15, 19, 20][TEST_PARAMETERS_INDEX];
-pub const TEST_RESOURCES_FOLDER: &str =
-    ["tree_height_15", "tree_height_19", "tree_height_20"][TEST_PARAMETERS_INDEX];
+    } else {
+        use std::io::Cursor;
+        use ark_circom::read_zkey;
+    }
+}
+
+const ZKEY_FILENAME: &str = "tree_height_20/rln_final.zkey";
+const VK_FILENAME: &str = "tree_height_20/verification_key.json";
+const WASM_FILENAME: &str = "tree_height_20/rln.wasm";
+
+pub const TEST_TREE_HEIGHT: usize = 20;
 
 #[cfg(not(target_arch = "wasm32"))]
 static RESOURCES_DIR: Dir<'_> = include_dir!("$CARGO_MANIFEST_DIR/resources");
@@ -54,8 +57,15 @@ 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)?;
+        let proving_key_and_matrices = match () {
+            #[cfg(feature = "arkzkey")]
+            () => read_arkzkey_from_bytes(zkey_data.as_slice())?,
+            #[cfg(not(feature = "arkzkey"))]
+            () => {
+                let mut c = Cursor::new(zkey_data);
+                read_zkey(&mut c)?
+            }
+        };
         Ok(proving_key_and_matrices)
     } else {
         Err(Report::msg("No proving key found!"))
@@ -64,13 +74,22 @@ pub fn zkey_from_raw(zkey_data: &Vec<u8>) -> Result<(ProvingKey<Curve>, Constrai
 
 // 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));
+pub fn zkey_from_folder() -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
+    #[cfg(feature = "arkzkey")]
+    let zkey = RESOURCES_DIR.get_file(Path::new(ARKZKEY_FILENAME));
+    #[cfg(not(feature = "arkzkey"))]
+    let zkey = RESOURCES_DIR.get_file(Path::new(ZKEY_FILENAME));
+
     if let Some(zkey) = zkey {
-        let mut c = Cursor::new(zkey.contents());
-        let proving_key_and_matrices = read_zkey(&mut c)?;
+        let proving_key_and_matrices = match () {
+            #[cfg(feature = "arkzkey")]
+            () => read_arkzkey_from_bytes(zkey.contents())?,
+            #[cfg(not(feature = "arkzkey"))]
+            () => {
+                let mut c = Cursor::new(zkey.contents());
+                read_zkey(&mut c)?
+            }
+        };
         Ok(proving_key_and_matrices)
     } else {
         Err(Report::msg("No proving key found!"))
@@ -78,7 +97,7 @@ pub fn zkey_from_folder(
 }
 
 // Loads the verification key from a bytes vector
-pub fn vk_from_raw(vk_data: &Vec<u8>, zkey_data: &Vec<u8>) -> Result<VerifyingKey<Curve>> {
+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() {
@@ -95,9 +114,9 @@ pub fn vk_from_raw(vk_data: &Vec<u8>, zkey_data: &Vec<u8>) -> Result<VerifyingKe
 
 // 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));
+pub fn vk_from_folder() -> Result<VerifyingKey<Curve>> {
+    let vk = RESOURCES_DIR.get_file(Path::new(VK_FILENAME));
+    let zkey = RESOURCES_DIR.get_file(Path::new(ZKEY_FILENAME));
 
     let verifying_key: VerifyingKey<Curve>;
     if let Some(vk) = vk {
@@ -106,7 +125,7 @@ pub fn vk_from_folder(resources_folder: &str) -> Result<VerifyingKey<Curve>> {
         ))?)?;
         Ok(verifying_key)
     } else if let Some(_zkey) = zkey {
-        let (proving_key, _matrices) = zkey_from_folder(resources_folder)?;
+        let (proving_key, _matrices) = zkey_from_folder()?;
         verifying_key = proving_key.vk;
         Ok(verifying_key)
     } else {
@@ -130,9 +149,9 @@ pub fn circom_from_raw(wasm_buffer: Vec<u8>) -> Result<&'static Mutex<WitnessCal
 
 // Initializes the witness calculator
 #[cfg(not(target_arch = "wasm32"))]
-pub fn circom_from_folder(resources_folder: &str) -> Result<&'static Mutex<WitnessCalculator>> {
+pub fn circom_from_folder() -> Result<&'static Mutex<WitnessCalculator>> {
     // We read the wasm file
-    let wasm = RESOURCES_DIR.get_file(Path::new(resources_folder).join(WASM_FILENAME));
+    let wasm = RESOURCES_DIR.get_file(Path::new(WASM_FILENAME));
 
     if let Some(wasm) = wasm {
         let wasm_buffer = wasm.contents();
@@ -146,7 +165,7 @@ pub fn circom_from_folder(resources_folder: &str) -> Result<&'static Mutex<Witne
 
 // Utilities to convert a json verification key in a groth16::VerificationKey
 fn fq_from_str(s: &str) -> Result<Fq> {
-    Ok(Fq::try_from(BigUint::from_str(s)?)?)
+    Ok(Fq::from(BigUint::from_str(s)?))
 }
 
 // Extracts the element in G1 corresponding to its JSON serialization
@@ -255,11 +274,8 @@ fn vk_from_vector(vk: &[u8]) -> Result<VerifyingKey<Curve>> {
 
 // 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 {

rln/src/ffi.rs

@@ -12,7 +12,15 @@ macro_rules! call {
     ($instance:expr, $method:ident $(, $arg:expr)*) => {
         {
             let new_instance: &mut RLN = $instance.process();
-            new_instance.$method($($arg.process()),*).is_ok()
+            match new_instance.$method($($arg.process()),*) {
+                Ok(()) => {
+                    true
+                }
+                Err(err) => {
+                    eprintln!("execution error: {err}");
+                    false
+                }
+            }
         }
     }
 }
@@ -30,13 +38,17 @@ macro_rules! call_with_output_arg {
         {
             let mut output_data: Vec<u8> = Vec::new();
             let new_instance = $instance.process();
-            if new_instance.$method(&mut output_data).is_ok() {
-                unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                std::mem::forget(output_data);
-                true
-            } else {
-                std::mem::forget(output_data);
-                false
+            match new_instance.$method(&mut output_data) {
+                Ok(()) => {
+                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
+                    std::mem::forget(output_data);
+                    true
+                }
+                Err(err) => {
+                    std::mem::forget(output_data);
+                    eprintln!("execution error: {err}");
+                    false
+                }
             }
         }
     };
@@ -44,13 +56,17 @@ macro_rules! call_with_output_arg {
         {
             let mut output_data: Vec<u8> = Vec::new();
             let new_instance = $instance.process();
-            if new_instance.$method($($arg.process()),*, &mut output_data).is_ok() {
-                unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                std::mem::forget(output_data);
-                true
-            } else {
-                std::mem::forget(output_data);
-                false
+            match new_instance.$method($($arg.process()),*, &mut output_data) {
+                Ok(()) => {
+                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
+                    std::mem::forget(output_data);
+                    true
+                }
+                Err(err) => {
+                    std::mem::forget(output_data);
+                    eprintln!("execution error: {err}");
+                    false
+                }
             }
         }
     };
@@ -66,13 +82,17 @@ macro_rules! no_ctx_call_with_output_arg {
     ($method:ident, $output_arg:expr, $( $arg:expr ),* ) => {
         {
             let mut output_data: Vec<u8> = Vec::new();
-            if $method($($arg.process()),*, &mut output_data).is_ok() {
-                unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                std::mem::forget(output_data);
-                true
-            } else {
-                std::mem::forget(output_data);
-                false
+            match $method($($arg.process()),*, &mut output_data) {
+                Ok(()) => {
+                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
+                    std::mem::forget(output_data);
+                    true
+                }
+                Err(err) => {
+                    std::mem::forget(output_data);
+                    eprintln!("execution error: {err}");
+                    false
+                }
             }
         }
     }
@@ -89,8 +109,11 @@ macro_rules! call_with_bool_arg {
         {
             let new_instance = $instance.process();
             if match new_instance.$method($($arg.process()),*,) {
-                Ok(verified) => verified,
-                Err(_) => return false,
+                Ok(result) => result,
+                Err(err) => {
+                    eprintln!("execution error: {err}");
+                    return false
+                },
             } {
                 unsafe { *$bool_arg = true };
             } else {
@@ -171,11 +194,15 @@ impl<'a> From<&Buffer> for &'a [u8] {
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
 pub extern "C" fn new(tree_height: usize, input_buffer: *const Buffer, ctx: *mut *mut RLN) -> bool {
-    if let Ok(rln) = RLN::new(tree_height, input_buffer.process()) {
-        unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-        true
-    } else {
-        false
+    match RLN::new(tree_height, input_buffer.process()) {
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
     }
 }
 
@@ -186,18 +213,24 @@ pub extern "C" fn new_with_params(
     circom_buffer: *const Buffer,
     zkey_buffer: *const Buffer,
     vk_buffer: *const Buffer,
+    tree_config: *const Buffer,
     ctx: *mut *mut RLN,
 ) -> bool {
-    if let Ok(rln) = RLN::new_with_params(
+    match RLN::new_with_params(
         tree_height,
         circom_buffer.process().to_vec(),
         zkey_buffer.process().to_vec(),
         vk_buffer.process().to_vec(),
+        tree_config.process(),
     ) {
-        unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-        true
-    } else {
-        false
+        Ok(rln) => {
+            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+            true
+        }
+        Err(err) => {
+            eprintln!("could not instantiate rln: {err}");
+            false
+        }
     }
 }
 
@@ -228,6 +261,12 @@ pub extern "C" fn get_leaf(ctx: *mut RLN, index: usize, output_buffer: *mut Buff
     call_with_output_arg!(ctx, get_leaf, output_buffer, index)
 }
 
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[no_mangle]
+pub extern "C" fn leaves_set(ctx: *mut RLN) -> usize {
+    ctx.process().leaves_set()
+}
+
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
 pub extern "C" fn set_next_leaf(ctx: *mut RLN, input_buffer: *const Buffer) -> bool {
@@ -261,6 +300,22 @@ pub extern "C" fn atomic_operation(
     call!(ctx, atomic_operation, index, leaves_buffer, indices_buffer)
 }
 
+#[allow(clippy::not_unsafe_ptr_arg_deref)]
+#[no_mangle]
+pub extern "C" fn seq_atomic_operation(
+    ctx: *mut RLN,
+    leaves_buffer: *const Buffer,
+    indices_buffer: *const Buffer,
+) -> bool {
+    call!(
+        ctx,
+        atomic_operation,
+        ctx.process().leaves_set(),
+        leaves_buffer,
+        indices_buffer
+    )
+}
+
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
 pub extern "C" fn get_root(ctx: *const RLN, output_buffer: *mut Buffer) -> bool {

rln/src/hashers.rs

@@ -1,13 +1,12 @@
-// This crate instantiate the Poseidon hash algorithm
-
+/// This crate instantiates the Poseidon hash algorithm.
 use crate::{circuit::Fr, utils::bytes_le_to_fr};
 use once_cell::sync::Lazy;
 use tiny_keccak::{Hasher, Keccak};
 use utils::poseidon::Poseidon;
 
-// These indexed constants hardcodes the supported round parameters tuples (t, RF, RN, SKIP_MATRICES) for the Bn254 scalar field
-// SKIP_MATRICES is the index of the randomly generated secure MDS matrix. See security note in the zerokit_utils::poseidon::poseidon_constants crate on this.
-// TODO: generate these parameters
+/// These indexed constants hardcode the supported round parameters tuples (t, RF, RN, SKIP_MATRICES) for the Bn254 scalar field.
+/// SKIP_MATRICES is the index of the randomly generated secure MDS matrix.
+/// TODO: generate these parameters
 pub const ROUND_PARAMS: [(usize, usize, usize, usize); 8] = [
     (2, 8, 56, 0),
     (3, 8, 57, 0),
@@ -19,7 +18,7 @@ pub const ROUND_PARAMS: [(usize, usize, usize, usize); 8] = [
     (9, 8, 63, 0),
 ];
 
-// Poseidon Hash wrapper over above implementation. Adapted from semaphore-rs poseidon hash wrapper.
+/// Poseidon Hash wrapper over above implementation.
 static POSEIDON: Lazy<Poseidon<Fr>> = Lazy::new(|| Poseidon::<Fr>::from(&ROUND_PARAMS));
 
 pub fn poseidon_hash(input: &[Fr]) -> Fr {
@@ -28,11 +27,11 @@ pub fn poseidon_hash(input: &[Fr]) -> Fr {
         .expect("hash with fixed input size can't fail")
 }
 
-// The zerokit RLN Merkle tree Hasher
+/// The zerokit RLN Merkle tree Hasher.
 #[derive(Clone, Copy, PartialEq, Eq)]
 pub struct PoseidonHash;
 
-// The default Hasher trait used by Merkle tree implementation in utils
+/// The default Hasher trait used by Merkle tree implementation in utils.
 impl utils::merkle_tree::Hasher for PoseidonHash {
     type Fr = Fr;
 
@@ -45,10 +44,9 @@ impl utils::merkle_tree::Hasher for PoseidonHash {
     }
 }
 
-// Hashes arbitrary signal to the underlying prime field
+/// Hashes arbitrary signal to the underlying prime field.
 pub fn hash_to_field(signal: &[u8]) -> Fr {
     // We hash the input signal using Keccak256
-    // (note that a bigger curve order might require a bigger hash blocksize)
     let mut hash = [0; 32];
     let mut hasher = Keccak::v256();
     hasher.update(signal);

rln/src/lib.rs

@@ -7,6 +7,8 @@ pub mod pm_tree_adapter;
 pub mod poseidon_tree;
 pub mod protocol;
 pub mod public;
+#[cfg(test)]
+pub mod public_api_tests;
 pub mod utils;
 
 #[cfg(not(target_arch = "wasm32"))]

rln/src/pm_tree_adapter.rs

@@ -1,19 +1,25 @@
-use crate::circuit::Fr;
-use crate::hashers::{poseidon_hash, PoseidonHash};
-use crate::utils::{bytes_le_to_fr, fr_to_bytes_le};
-use color_eyre::{Report, Result};
-use serde_json::Value;
-use std::collections::HashSet;
 use std::fmt::Debug;
 use std::path::PathBuf;
 use std::str::FromStr;
+
+use color_eyre::{Report, Result};
+use serde_json::Value;
+
+use utils::pmtree::tree::Key;
 use utils::pmtree::{Database, Hasher};
 use utils::*;
 
+use crate::circuit::Fr;
+use crate::hashers::{poseidon_hash, PoseidonHash};
+use crate::utils::{bytes_le_to_fr, fr_to_bytes_le};
+
 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>,
 }
@@ -25,13 +31,9 @@ pub struct PmTreeProof {
 pub type FrOf<H> = <H as Hasher>::Fr;
 
 // The pmtree Hasher trait used by pmtree Merkle tree
-impl pmtree::Hasher for PoseidonHash {
+impl Hasher for PoseidonHash {
     type Fr = Fr;
 
-    fn default_leaf() -> Self::Fr {
-        Fr::from(0)
-    }
-
     fn serialize(value: Self::Fr) -> pmtree::Value {
         fr_to_bytes_le(&value)
     }
@@ -41,12 +43,16 @@ impl pmtree::Hasher for PoseidonHash {
         fr
     }
 
+    fn default_leaf() -> Self::Fr {
+        Fr::from(0)
+    }
+
     fn hash(inputs: &[Self::Fr]) -> Self::Fr {
         poseidon_hash(inputs)
     }
 }
 
-fn get_tmp_path() -> std::path::PathBuf {
+fn get_tmp_path() -> PathBuf {
     std::env::temp_dir().join(format!("pmtree-{}", rand::random::<u64>()))
 }
 
@@ -54,7 +60,7 @@ fn get_tmp() -> bool {
     true
 }
 
-pub struct PmtreeConfig(pm_tree::Config);
+pub struct PmtreeConfig(Config);
 
 impl FromStr for PmtreeConfig {
     type Err = Report;
@@ -85,7 +91,7 @@ impl FromStr for PmtreeConfig {
             )));
         }
 
-        let config = pm_tree::Config::new()
+        let config = Config::new()
             .temporary(temporary.unwrap_or(get_tmp()))
             .path(path.unwrap_or(get_tmp_path()))
             .cache_capacity(cache_capacity.unwrap_or(1024 * 1024 * 1024))
@@ -100,7 +106,7 @@ impl Default for PmtreeConfig {
     fn default() -> Self {
         let tmp_path = get_tmp_path();
         PmtreeConfig(
-            pm_tree::Config::new()
+            Config::new()
                 .temporary(true)
                 .path(tmp_path)
                 .cache_capacity(150_000)
@@ -141,14 +147,11 @@ impl ZerokitMerkleTree for PmTree {
 
         Ok(PmTree {
             tree,
+            cached_leaves_indices: vec![0; 1 << depth],
             metadata: Vec::new(),
         })
     }
 
-    fn close_db_connection(&mut self) -> Result<()> {
-        self.tree.db.close().map_err(|e| Report::msg(e.to_string()))
-    }
-
     fn depth(&self) -> usize {
         self.tree.depth()
     }
@@ -157,7 +160,7 @@ impl ZerokitMerkleTree for PmTree {
         self.tree.capacity()
     }
 
-    fn leaves_set(&mut self) -> usize {
+    fn leaves_set(&self) -> usize {
         self.tree.leaves_set()
     }
 
@@ -165,14 +168,16 @@ impl ZerokitMerkleTree for PmTree {
         self.tree.root()
     }
 
+    fn compute_root(&mut self) -> Result<FrOf<Self::Hasher>> {
+        Ok(self.tree.root())
+    }
+
     fn set(&mut self, index: usize, leaf: FrOf<Self::Hasher>) -> Result<()> {
         self.tree
             .set(index, leaf)
-            .map_err(|e| Report::msg(e.to_string()))
-    }
-
-    fn get(&self, index: usize) -> Result<FrOf<Self::Hasher>> {
-        self.tree.get(index).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>>>(
@@ -180,9 +185,49 @@ 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>>(
@@ -192,33 +237,17 @@ impl ZerokitMerkleTree for PmTree {
         indices: J,
     ) -> Result<()> {
         let leaves = leaves.into_iter().collect::<Vec<_>>();
-        let indices = indices.into_iter().collect::<HashSet<_>>();
-        let end = start + leaves.len();
+        let mut indices = indices.into_iter().collect::<Vec<_>>();
+        indices.sort();
 
-        if leaves.len() + start - indices.len() > self.capacity() {
-            return Err(Report::msg("index out of bounds"));
+        match (leaves.len(), indices.len()) {
+            (0, 0) => Err(Report::msg("no leaves or indices to be removed")),
+            (1, 0) => self.set(start, leaves[0]),
+            (0, 1) => self.delete(indices[0]),
+            (_, 0) => self.set_range(start, leaves),
+            (0, _) => self.remove_indices(&indices),
+            (_, _) => self.remove_indices_and_set_leaves(start, leaves, &indices),
         }
-
-        // extend the range to include indices to be removed
-        let min_index = indices.iter().min().unwrap_or(&start);
-        let max_index = indices.iter().max().unwrap_or(&end);
-
-        let mut new_leaves = Vec::new();
-
-        // insert leaves into new_leaves
-        for i in *min_index..*max_index {
-            if indices.contains(&i) {
-                // insert 0
-                new_leaves.push(Self::Hasher::default_leaf());
-            } else {
-                // insert leaf
-                new_leaves.push(leaves[i - start]);
-            }
-        }
-
-        self.tree
-            .set_range(start, new_leaves)
-            .map_err(|e| Report::msg(e.to_string()))
     }
 
     fn update_next(&mut self, leaf: FrOf<Self::Hasher>) -> Result<()> {
@@ -230,7 +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> {
@@ -246,10 +277,6 @@ impl ZerokitMerkleTree for PmTree {
         }
     }
 
-    fn compute_root(&mut self) -> Result<FrOf<Self::Hasher>> {
-        Ok(self.tree.root())
-    }
-
     fn set_metadata(&mut self, metadata: &[u8]) -> Result<()> {
         self.tree.db.put(METADATA_KEY, metadata.to_vec())?;
         self.metadata = metadata.to_vec();
@@ -264,10 +291,72 @@ impl ZerokitMerkleTree for PmTree {
         let data = self.tree.db.get(METADATA_KEY)?;
 
         if data.is_none() {
-            return Err(Report::msg("metadata does not exist"));
+            // send empty Metadata
+            return Ok(Vec::new());
         }
         Ok(data.unwrap())
     }
+
+    fn close_db_connection(&mut self) -> Result<()> {
+        self.tree.db.close().map_err(|e| Report::msg(e.to_string()))
+    }
+}
+
+type PmTreeHasher = <PmTree as ZerokitMerkleTree>::Hasher;
+type FrOfPmTreeHasher = FrOf<PmTreeHasher>;
+
+impl PmTree {
+    fn remove_indices(&mut self, indices: &[usize]) -> Result<()> {
+        let start = indices[0];
+        let end = indices.last().unwrap() + 1;
+
+        let new_leaves = (start..end).map(|_| PmTreeHasher::default_leaf());
+
+        self.tree
+            .set_range(start, new_leaves)
+            .map_err(|e| Report::msg(e.to_string()))?;
+
+        for i in start..end {
+            self.cached_leaves_indices[i] = 0
+        }
+        Ok(())
+    }
+
+    fn remove_indices_and_set_leaves(
+        &mut self,
+        start: usize,
+        leaves: Vec<FrOfPmTreeHasher>,
+        indices: &[usize],
+    ) -> Result<()> {
+        let min_index = *indices.first().unwrap();
+        let max_index = start + leaves.len();
+
+        let mut set_values = vec![PmTreeHasher::default_leaf(); max_index - min_index];
+
+        for i in min_index..start {
+            if !indices.contains(&i) {
+                let value = self.tree.get(i)?;
+                set_values[i - min_index] = value;
+            }
+        }
+
+        for (i, &leaf) in leaves.iter().enumerate() {
+            set_values[start - min_index + i] = leaf;
+        }
+
+        self.tree
+            .set_range(start, set_values)
+            .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(())
+    }
 }
 
 impl ZerokitMerkleProof for PmTreeProof {

rln/src/protocol.rs

@@ -4,11 +4,13 @@ use ark_circom::{CircomReduction, WitnessCalculator};
 use ark_groth16::{prepare_verifying_key, Groth16, Proof as ArkProof, ProvingKey, VerifyingKey};
 use ark_relations::r1cs::ConstraintMatrices;
 use ark_relations::r1cs::SynthesisError;
+use ark_serialize::{CanonicalDeserialize, CanonicalSerialize};
 use ark_std::{rand::thread_rng, UniformRand};
 use color_eyre::{Report, Result};
 use num_bigint::BigInt;
 use rand::{Rng, SeedableRng};
 use rand_chacha::ChaCha20Rng;
+use serde::{Deserialize, Serialize};
 #[cfg(not(target_arch = "wasm32"))]
 use std::sync::Mutex;
 #[cfg(debug_assertions)]
@@ -29,14 +31,21 @@ use utils::{ZerokitMerkleProof, ZerokitMerkleTree};
 // RLN Witness data structure and utility functions
 ///////////////////////////////////////////////////////
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
 pub struct RLNWitnessInput {
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
     identity_secret: Fr,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
+    user_message_limit: Fr,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
+    message_id: Fr,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
     path_elements: Vec<Fr>,
     identity_path_index: Vec<u8>,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
     x: Fr,
-    epoch: Fr,
-    rln_identifier: Fr,
+    #[serde(serialize_with = "ark_se", deserialize_with = "ark_de")]
+    external_nullifier: Fr,
 }
 
 #[derive(Debug, PartialEq)]
@@ -47,8 +56,7 @@ pub struct RLNProofValues {
     pub root: Fr,
     // Public Inputs:
     pub x: Fr,
-    pub epoch: Fr,
-    pub rln_identifier: Fr,
+    pub external_nullifier: Fr,
 }
 
 pub fn serialize_field_element(element: Fr) -> Vec<u8> {
@@ -90,25 +98,46 @@ pub fn deserialize_identity_tuple(serialized: Vec<u8>) -> (Fr, Fr, Fr, Fr) {
     )
 }
 
+/// Serializes witness
+///
+/// # Errors
+///
+/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
 pub fn serialize_witness(rln_witness: &RLNWitnessInput) -> Result<Vec<u8>> {
+    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.epoch));
-    serialized.append(&mut fr_to_bytes_le(&rln_witness.rln_identifier));
+    serialized.append(&mut fr_to_bytes_le(&rln_witness.external_nullifier));
 
     Ok(serialized)
 }
 
+/// Deserializes witness
+///
+/// # Errors
+///
+/// Returns an error if `message_id` is not within `user_message_limit`.
 pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)> {
     let mut all_read: usize = 0;
 
     let (identity_secret, read) = bytes_le_to_fr(&serialized[all_read..]);
     all_read += read;
 
+    let (user_message_limit, read) = bytes_le_to_fr(&serialized[all_read..]);
+    all_read += read;
+
+    let (message_id, read) = bytes_le_to_fr(&serialized[all_read..]);
+    all_read += read;
+
+    message_id_range_check(&message_id, &user_message_limit)?;
+
     let (path_elements, read) = bytes_le_to_vec_fr(&serialized[all_read..])?;
     all_read += read;
 
@@ -118,13 +147,9 @@ pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)
     let (x, read) = bytes_le_to_fr(&serialized[all_read..]);
     all_read += read;
 
-    let (epoch, read) = bytes_le_to_fr(&serialized[all_read..]);
+    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
     all_read += read;
 
-    let (rln_identifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
-    // TODO: check rln_identifier against public::RLN_IDENTIFIER
     if serialized.len() != all_read {
         return Err(Report::msg("serialized length is not equal to all_read"));
     }
@@ -135,8 +160,9 @@ pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)
             path_elements,
             identity_path_index,
             x,
-            epoch,
-            rln_identifier,
+            external_nullifier,
+            user_message_limit,
+            message_id,
         },
         all_read,
     ))
@@ -144,7 +170,7 @@ pub fn deserialize_witness(serialized: &[u8]) -> Result<(RLNWitnessInput, usize)
 
 // This function deserializes input for kilic's rln generate_proof public API
 // https://github.com/kilic/rln/blob/7ac74183f8b69b399e3bc96c1ae8ab61c026dc43/src/public.rs#L148
-// input_data is [ identity_secret<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]
+// input_data is [ identity_secret<32> | id_index<8> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
 // return value is a rln witness populated according to this information
 pub fn proof_inputs_to_rln_witness(
     tree: &mut PoseidonTree,
@@ -160,7 +186,13 @@ pub fn proof_inputs_to_rln_witness(
     ))?;
     all_read += 8;
 
-    let (epoch, read) = bytes_le_to_fr(&serialized[all_read..]);
+    let (user_message_limit, read) = bytes_le_to_fr(&serialized[all_read..]);
+    all_read += read;
+
+    let (message_id, read) = bytes_le_to_fr(&serialized[all_read..]);
+    all_read += read;
+
+    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
     all_read += read;
 
     let signal_len = usize::try_from(u64::from_le_bytes(
@@ -176,83 +208,49 @@ pub fn proof_inputs_to_rln_witness(
 
     let x = hash_to_field(&signal);
 
-    let rln_identifier = hash_to_field(RLN_IDENTIFIER);
-
     Ok((
         RLNWitnessInput {
             identity_secret,
             path_elements,
             identity_path_index,
+            user_message_limit,
+            message_id,
             x,
-            epoch,
-            rln_identifier,
+            external_nullifier,
         },
         all_read,
     ))
 }
 
-pub fn rln_witness_from_json(input_json_str: &str) -> Result<RLNWitnessInput> {
-    let input_json: serde_json::Value =
-        serde_json::from_str(input_json_str).expect("JSON was not well-formatted");
+/// Creates `RLNWitnessInput` from it's fields.
+///
+/// # Errors
+///
+/// Returns an error if `message_id` is not within `user_message_limit`.
+pub fn rln_witness_from_values(
+    identity_secret: Fr,
+    merkle_proof: &MerkleProof,
+    x: Fr,
+    external_nullifier: Fr,
+    user_message_limit: Fr,
+    message_id: Fr,
+) -> Result<RLNWitnessInput> {
+    message_id_range_check(&message_id, &user_message_limit)?;
 
-    let identity_secret = str_to_fr(&input_json["identity_secret"].to_string(), 10)?;
-
-    let path_elements = input_json["path_elements"]
-        .as_array()
-        .ok_or(Report::msg("not an array"))?
-        .iter()
-        .map(|v| str_to_fr(&v.to_string(), 10))
-        .collect::<Result<_>>()?;
-
-    let identity_path_index_array = input_json["identity_path_index"]
-        .as_array()
-        .ok_or(Report::msg("not an arrray"))?;
-
-    let mut identity_path_index: Vec<u8> = vec![];
-
-    for v in identity_path_index_array {
-        identity_path_index.push(v.as_u64().ok_or(Report::msg("not a u64 value"))? as u8);
-    }
-
-    let x = str_to_fr(&input_json["x"].to_string(), 10)?;
-
-    let epoch = str_to_fr(&input_json["epoch"].to_string(), 16)?;
-
-    let rln_identifier = str_to_fr(&input_json["rln_identifier"].to_string(), 10)?;
-
-    // TODO: check rln_identifier against public::RLN_IDENTIFIER
+    let path_elements = merkle_proof.get_path_elements();
+    let identity_path_index = merkle_proof.get_path_index();
 
     Ok(RLNWitnessInput {
         identity_secret,
         path_elements,
         identity_path_index,
         x,
-        epoch,
-        rln_identifier,
+        external_nullifier,
+        user_message_limit,
+        message_id,
     })
 }
 
-pub fn rln_witness_from_values(
-    identity_secret: Fr,
-    merkle_proof: &MerkleProof,
-    x: Fr,
-    epoch: Fr,
-    //rln_identifier: Fr,
-) -> RLNWitnessInput {
-    let path_elements = merkle_proof.get_path_elements();
-    let identity_path_index = merkle_proof.get_path_index();
-    let rln_identifier = hash_to_field(RLN_IDENTIFIER);
-
-    RLNWitnessInput {
-        identity_secret,
-        path_elements,
-        identity_path_index,
-        x,
-        epoch,
-        rln_identifier,
-    }
-}
-
 pub fn random_rln_witness(tree_height: usize) -> RLNWitnessInput {
     let mut rng = thread_rng();
 
@@ -269,21 +267,26 @@ pub fn random_rln_witness(tree_height: usize) -> RLNWitnessInput {
         identity_path_index.push(rng.gen_range(0..2) as u8);
     }
 
+    let user_message_limit = Fr::from(100);
+    let message_id = Fr::from(1);
+
     RLNWitnessInput {
         identity_secret,
         path_elements,
         identity_path_index,
         x,
-        epoch,
-        rln_identifier,
+        external_nullifier: poseidon_hash(&[epoch, rln_identifier]),
+        user_message_limit,
+        message_id,
     }
 }
 
-pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> RLNProofValues {
+pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> Result<RLNProofValues> {
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
+
     // y share
-    let external_nullifier = poseidon_hash(&[rln_witness.epoch, rln_witness.rln_identifier]);
     let a_0 = rln_witness.identity_secret;
-    let a_1 = poseidon_hash(&[a_0, external_nullifier]);
+    let a_1 = poseidon_hash(&[a_0, rln_witness.external_nullifier, rln_witness.message_id]);
     let y = a_0 + rln_witness.x * a_1;
 
     // Nullifier
@@ -292,30 +295,28 @@ pub fn proof_values_from_witness(rln_witness: &RLNWitnessInput) -> RLNProofValue
     // Merkle tree root computations
     let root = compute_tree_root(
         &rln_witness.identity_secret,
+        &rln_witness.user_message_limit,
         &rln_witness.path_elements,
         &rln_witness.identity_path_index,
-        true,
     );
 
-    RLNProofValues {
+    Ok(RLNProofValues {
         y,
         nullifier,
         root,
         x: rln_witness.x,
-        epoch: rln_witness.epoch,
-        rln_identifier: rln_witness.rln_identifier,
-    }
+        external_nullifier: rln_witness.external_nullifier,
+    })
 }
 
 pub fn serialize_proof_values(rln_proof_values: &RLNProofValues) -> Vec<u8> {
     let mut serialized: Vec<u8> = Vec::new();
 
     serialized.append(&mut fr_to_bytes_le(&rln_proof_values.root));
-    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.epoch));
+    serialized.append(&mut fr_to_bytes_le(&rln_proof_values.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.append(&mut fr_to_bytes_le(&rln_proof_values.rln_identifier));
 
     serialized
 }
@@ -328,7 +329,7 @@ pub fn deserialize_proof_values(serialized: &[u8]) -> (RLNProofValues, usize) {
     let (root, read) = bytes_le_to_fr(&serialized[all_read..]);
     all_read += read;
 
-    let (epoch, read) = bytes_le_to_fr(&serialized[all_read..]);
+    let (external_nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
     all_read += read;
 
     let (x, read) = bytes_le_to_fr(&serialized[all_read..]);
@@ -340,17 +341,13 @@ pub fn deserialize_proof_values(serialized: &[u8]) -> (RLNProofValues, usize) {
     let (nullifier, read) = bytes_le_to_fr(&serialized[all_read..]);
     all_read += read;
 
-    let (rln_identifier, read) = bytes_le_to_fr(&serialized[all_read..]);
-    all_read += read;
-
     (
         RLNProofValues {
             y,
             nullifier,
             root,
             x,
-            epoch,
-            rln_identifier,
+            external_nullifier,
         },
         all_read,
     )
@@ -359,14 +356,14 @@ pub fn deserialize_proof_values(serialized: &[u8]) -> (RLNProofValues, usize) {
 pub fn prepare_prove_input(
     identity_secret: Fr,
     id_index: usize,
-    epoch: Fr,
+    external_nullifier: Fr,
     signal: &[u8],
 ) -> Vec<u8> {
     let mut serialized: Vec<u8> = Vec::new();
 
     serialized.append(&mut fr_to_bytes_le(&identity_secret));
     serialized.append(&mut normalize_usize(id_index));
-    serialized.append(&mut fr_to_bytes_le(&epoch));
+    serialized.append(&mut fr_to_bytes_le(&external_nullifier));
     serialized.append(&mut normalize_usize(signal.len()));
     serialized.append(&mut signal.to_vec());
 
@@ -389,15 +386,13 @@ pub fn prepare_verify_input(proof_data: Vec<u8>, signal: &[u8]) -> Vec<u8> {
 ///////////////////////////////////////////////////////
 
 pub fn compute_tree_root(
-    leaf: &Fr,
+    identity_secret: &Fr,
+    user_message_limit: &Fr,
     path_elements: &[Fr],
     identity_path_index: &[u8],
-    hash_leaf: bool,
 ) -> Fr {
-    let mut root = *leaf;
-    if hash_leaf {
-        root = poseidon_hash(&[root]);
-    }
+    let id_commitment = poseidon_hash(&[*identity_secret]);
+    let mut root = poseidon_hash(&[id_commitment, *user_message_limit]);
 
     for i in 0..identity_path_index.len() {
         if identity_path_index[i] == 0 {
@@ -488,11 +483,7 @@ pub fn extended_seeded_keygen(signal: &[u8]) -> (Fr, Fr, Fr, Fr) {
     )
 }
 
-pub fn compute_id_secret(
-    share1: (Fr, Fr),
-    share2: (Fr, Fr),
-    external_nullifier: Fr,
-) -> Result<Fr, String> {
+pub fn compute_id_secret(share1: (Fr, Fr), share2: (Fr, Fr)) -> Result<Fr, String> {
     // Assuming a0 is the identity secret and a1 = poseidonHash([a0, external_nullifier]),
     // a (x,y) share satisfies the following relation
     // y = a_0 + x * a_1
@@ -506,14 +497,7 @@ pub fn compute_id_secret(
     let a_0 = y1 - x1 * a_1;
 
     // If shares come from the same polynomial, a0 is correctly recovered and a1 = poseidonHash([a0, external_nullifier])
-    let computed_a_1 = poseidon_hash(&[a_0, external_nullifier]);
-
-    if a_1 == computed_a_1 {
-        // We successfully recovered the identity secret
-        Ok(a_0)
-    } else {
-        Err("Cannot recover identity_secret_hash from provided shares".into())
-    }
+    Ok(a_0)
 }
 
 ///////////////////////////////////////////////////////
@@ -594,10 +578,17 @@ pub fn generate_proof_with_witness(
     Ok(proof)
 }
 
+/// Formats inputs for witness calculation
+///
+/// # Errors
+///
+/// Returns an error if `rln_witness.message_id` is not within `rln_witness.user_message_limit`.
 pub fn inputs_for_witness_calculation(
     rln_witness: &RLNWitnessInput,
-) -> Result<[(&str, Vec<BigInt>); 6]> {
-    // We confert the path indexes to field elements
+) -> Result<[(&str, Vec<BigInt>); 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();
 
@@ -613,16 +604,20 @@ pub fn inputs_for_witness_calculation(
 
     Ok([
         (
-            "identity_secret",
+            "identitySecret",
             vec![to_bigint(&rln_witness.identity_secret)?],
         ),
-        ("path_elements", path_elements),
-        ("identity_path_index", identity_path_index),
-        ("x", vec![to_bigint(&rln_witness.x)?]),
-        ("epoch", vec![to_bigint(&rln_witness.epoch)?]),
         (
-            "rln_identifier",
-            vec![to_bigint(&rln_witness.rln_identifier)?],
+            "userMessageLimit",
+            vec![to_bigint(&rln_witness.user_message_limit)?],
+        ),
+        ("messageId", vec![to_bigint(&rln_witness.message_id)?]),
+        ("pathElements", path_elements),
+        ("identityPathIndex", identity_path_index),
+        ("x", vec![to_bigint(&rln_witness.x)?]),
+        (
+            "externalNullifier",
+            vec![to_bigint(&rln_witness.external_nullifier)?],
         ),
     ])
 }
@@ -671,7 +666,6 @@ pub fn generate_proof(
     // If in debug mode, we measure and later print time take to compute proof
     #[cfg(debug_assertions)]
     let now = Instant::now();
-
     let proof = Groth16::<_, CircomReduction>::create_proof_with_reduction_and_matrices(
         &proving_key.0,
         r,
@@ -705,8 +699,7 @@ pub fn verify_proof(
         proof_values.root,
         proof_values.nullifier,
         proof_values.x,
-        proof_values.epoch,
-        proof_values.rln_identifier,
+        proof_values.external_nullifier,
     ];
 
     // Check that the proof is valid
@@ -725,31 +718,56 @@ pub fn verify_proof(
     Ok(verified)
 }
 
-/// Get CIRCOM JSON inputs
-///
-/// Returns a JSON object containing the inputs necessary to calculate
-/// the witness with CIRCOM on javascript
-pub fn get_json_inputs(rln_witness: &RLNWitnessInput) -> Result<serde_json::Value> {
-    let mut path_elements = Vec::new();
-
-    for v in rln_witness.path_elements.iter() {
-        path_elements.push(to_bigint(v)?.to_str_radix(10));
-    }
-
-    let mut identity_path_index = Vec::new();
-    rln_witness
-        .identity_path_index
-        .iter()
-        .for_each(|v| identity_path_index.push(BigInt::from(*v).to_str_radix(10)));
-
-    let inputs = serde_json::json!({
-        "identity_secret": to_bigint(&rln_witness.identity_secret)?.to_str_radix(10),
-        "path_elements": path_elements,
-        "identity_path_index": identity_path_index,
-        "x": to_bigint(&rln_witness.x)?.to_str_radix(10),
-        "epoch":  format!("0x{:064x}", to_bigint(&rln_witness.epoch)?),
-        "rln_identifier": to_bigint(&rln_witness.rln_identifier)?.to_str_radix(10),
-    });
-
-    Ok(inputs)
+// auxiliary function for serialisation Fr to json using ark serilize
+fn ark_se<S, A: CanonicalSerialize>(a: &A, s: S) -> Result<S::Ok, S::Error>
+where
+    S: serde::Serializer,
+{
+    let mut bytes = vec![];
+    a.serialize_compressed(&mut bytes)
+        .map_err(serde::ser::Error::custom)?;
+    s.serialize_bytes(&bytes)
+}
+
+// auxiliary function for deserialisation Fr to json using ark serilize
+fn ark_de<'de, D, A: CanonicalDeserialize>(data: D) -> Result<A, D::Error>
+where
+    D: serde::de::Deserializer<'de>,
+{
+    let s: Vec<u8> = serde::de::Deserialize::deserialize(data)?;
+    let a = A::deserialize_compressed_unchecked(s.as_slice());
+    a.map_err(serde::de::Error::custom)
+}
+
+/// Converts a [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object to the corresponding JSON serialization.
+///
+/// # Errors
+///
+/// Returns an error if `message_id` is not within `user_message_limit`.
+pub fn rln_witness_from_json(input_json: serde_json::Value) -> Result<RLNWitnessInput> {
+    let rln_witness: RLNWitnessInput = serde_json::from_value(input_json).unwrap();
+    message_id_range_check(&rln_witness.message_id, &rln_witness.user_message_limit)?;
+
+    Ok(rln_witness)
+}
+
+/// Converts a JSON value into [`RLNWitnessInput`](crate::protocol::RLNWitnessInput) object.
+///
+/// # Errors
+///
+/// Returns an error if `rln_witness.message_id` is not within `rln_witness.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)
+}
+
+pub fn message_id_range_check(message_id: &Fr, user_message_limit: &Fr) -> Result<()> {
+    if message_id > user_message_limit {
+        return Err(color_eyre::Report::msg(
+            "message_id is not within user_message_limit",
+        ));
+    }
+    Ok(())
 }

rln/src/public_api_tests.rs

@@ -0,0 +1,980 @@
+use crate::circuit::{Curve, Fr, TEST_TREE_HEIGHT};
+use crate::hashers::{hash_to_field, poseidon_hash as utils_poseidon_hash};
+use crate::protocol::*;
+use crate::public::RLN;
+use crate::utils::*;
+use ark_groth16::Proof as ArkProof;
+use ark_serialize::{CanonicalDeserialize, Read};
+use num_bigint::BigInt;
+use std::io::Cursor;
+use std::str::FromStr;
+use utils::ZerokitMerkleTree;
+
+use ark_std::{rand::thread_rng, UniformRand};
+use rand::Rng;
+use serde_json::{json, Value};
+
+#[test]
+// We test merkle batch Merkle tree additions
+fn test_merkle_operations() {
+    let tree_height = TEST_TREE_HEIGHT;
+    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 {
+        leaves.push(Fr::rand(&mut rng));
+    }
+
+    // We create a new tree
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We first add leaves one by one specifying the index
+    for (i, leaf) in leaves.iter().enumerate() {
+        // We check if the number of leaves set is consistent
+        assert_eq!(rln.tree.leaves_set(), i);
+
+        let mut buffer = Cursor::new(fr_to_bytes_le(&leaf));
+        rln.set_leaf(i, &mut buffer).unwrap();
+    }
+
+    // We get the root of the tree obtained adding one leaf per time
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_single, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    // We reset the tree to default
+    rln.set_tree(tree_height).unwrap();
+
+    // We add leaves one by one using the internal index (new leaves goes in next available position)
+    for leaf in &leaves {
+        let mut buffer = Cursor::new(fr_to_bytes_le(&leaf));
+        rln.set_next_leaf(&mut buffer).unwrap();
+    }
+
+    // We check if numbers of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    // We get the root of the tree obtained adding leaves using the internal index
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_next, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_eq!(root_single, root_next);
+
+    // We reset the tree to default
+    rln.set_tree(tree_height).unwrap();
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    // We get the root of the tree obtained adding leaves in batch
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_batch, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_eq!(root_single, root_batch);
+
+    // We now delete all leaves set and check if the root corresponds to the empty tree root
+    // delete calls over indexes higher than no_of_leaves are ignored and will not increase self.tree.next_index
+    for i in 0..no_of_leaves {
+        rln.delete_leaf(i).unwrap();
+    }
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_delete, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    // We reset the tree to default
+    rln.set_tree(tree_height).unwrap();
+
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_empty, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_eq!(root_delete, root_empty);
+}
+
+#[test]
+// We test leaf setting with a custom index, to enable batch updates to the root
+// Uses `set_leaves_from` to set leaves in a batch, from index `start_index`
+fn test_leaf_setting_with_index() {
+    let tree_height = TEST_TREE_HEIGHT;
+    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 {
+        leaves.push(Fr::rand(&mut rng));
+    }
+
+    // set_index is the index from which we start setting leaves
+    // random number between 0..no_of_leaves
+    let set_index = rng.gen_range(0..no_of_leaves) as usize;
+
+    // We create a new tree
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    // We get the root of the tree obtained adding leaves in batch
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_batch_with_init, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    // `init_tree_with_leaves` resets the tree to the height it was initialized with, using `set_tree`
+
+    // We add leaves in a batch starting from index 0..set_index
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves[0..set_index]).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // We add the remaining n leaves in a batch starting from index m
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves[set_index..]).unwrap());
+    rln.set_leaves_from(set_index, &mut buffer).unwrap();
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    // We get the root of the tree obtained adding leaves in batch
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_batch_with_custom_index, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_eq!(root_batch_with_init, root_batch_with_custom_index);
+
+    // We reset the tree to default
+    rln.set_tree(tree_height).unwrap();
+
+    // We add leaves one by one using the internal index (new leaves goes in next available position)
+    for leaf in &leaves {
+        let mut buffer = Cursor::new(fr_to_bytes_le(&leaf));
+        rln.set_next_leaf(&mut buffer).unwrap();
+    }
+
+    // We check if numbers of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    // We get the root of the tree obtained adding leaves using the internal index
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_single_additions, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_eq!(root_batch_with_init, root_single_additions);
+
+    rln.flush().unwrap();
+}
+
+#[test]
+// Tests the atomic_operation fn, which set_leaves_from uses internally
+fn test_atomic_operation() {
+    let tree_height = TEST_TREE_HEIGHT;
+    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 {
+        leaves.push(Fr::rand(&mut rng));
+    }
+
+    // We create a new tree
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    // We get the root of the tree obtained adding leaves in batch
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_after_insertion, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    let last_leaf = leaves.last().unwrap();
+    let last_leaf_index = no_of_leaves - 1;
+    let indices = vec![last_leaf_index as u8];
+    let last_leaf = vec![*last_leaf];
+    let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices).unwrap());
+    let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&last_leaf).unwrap());
+
+    rln.atomic_operation(last_leaf_index, leaves_buffer, indices_buffer)
+        .unwrap();
+
+    // We get the root of the tree obtained after a no-op
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_after_noop, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_eq!(root_after_insertion, root_after_noop);
+}
+
+#[test]
+fn test_atomic_operation_zero_indexed() {
+    // Test duplicated from https://github.com/waku-org/go-zerokit-rln/pull/12/files
+    let tree_height = TEST_TREE_HEIGHT;
+    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 {
+        leaves.push(Fr::rand(&mut rng));
+    }
+
+    // We create a new tree
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    // We get the root of the tree obtained adding leaves in batch
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_after_insertion, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    let zero_index = 0;
+    let indices = vec![zero_index as u8];
+    let zero_leaf: Vec<Fr> = vec![];
+    let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices).unwrap());
+    let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&zero_leaf).unwrap());
+    rln.atomic_operation(0, leaves_buffer, indices_buffer)
+        .unwrap();
+
+    // We get the root of the tree obtained after a deletion
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_after_deletion, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_ne!(root_after_insertion, root_after_deletion);
+}
+
+#[test]
+fn test_atomic_operation_consistency() {
+    // Test duplicated from https://github.com/waku-org/go-zerokit-rln/pull/12/files
+    let tree_height = TEST_TREE_HEIGHT;
+    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 {
+        leaves.push(Fr::rand(&mut rng));
+    }
+
+    // We create a new tree
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), no_of_leaves);
+
+    // We get the root of the tree obtained adding leaves in batch
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_after_insertion, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    let set_index = rng.gen_range(0..no_of_leaves) as usize;
+    let indices = vec![set_index as u8];
+    let zero_leaf: Vec<Fr> = vec![];
+    let indices_buffer = Cursor::new(vec_u8_to_bytes_le(&indices).unwrap());
+    let leaves_buffer = Cursor::new(vec_fr_to_bytes_le(&zero_leaf).unwrap());
+    rln.atomic_operation(0, leaves_buffer, indices_buffer)
+        .unwrap();
+
+    // We get the root of the tree obtained after a deletion
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_after_deletion, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_ne!(root_after_insertion, root_after_deletion);
+
+    // We get the leaf
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_leaf(set_index, &mut output_buffer).unwrap();
+    let (received_leaf, _) = bytes_le_to_fr(output_buffer.into_inner().as_ref());
+
+    assert_eq!(received_leaf, Fr::from(0));
+}
+
+#[allow(unused_must_use)]
+#[test]
+// This test checks if `set_leaves_from` throws an error when the index is out of bounds
+fn test_set_leaves_bad_index() {
+    let tree_height = TEST_TREE_HEIGHT;
+    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 {
+        leaves.push(Fr::rand(&mut rng));
+    }
+    let bad_index = (1 << tree_height) - rng.gen_range(0..no_of_leaves) as usize;
+
+    // We create a new tree
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // Get root of empty tree
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_empty, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.set_leaves_from(bad_index, &mut buffer)
+        .expect_err("Should throw an error");
+
+    // We check if number of leaves set is consistent
+    assert_eq!(rln.tree.leaves_set(), 0);
+
+    // Get the root of the tree
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root_after_bad_set, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    assert_eq!(root_empty, root_after_bad_set);
+}
+
+fn fq_from_str(s: String) -> ark_bn254::Fq {
+    ark_bn254::Fq::from_str(&s).unwrap()
+}
+
+fn g1_from_str(g1: &[String]) -> ark_bn254::G1Affine {
+    let x = fq_from_str(g1[0].clone());
+    let y = fq_from_str(g1[1].clone());
+    let z = fq_from_str(g1[2].clone());
+    ark_bn254::G1Affine::from(ark_bn254::G1Projective::new(x, y, z))
+}
+
+fn g2_from_str(g2: &[Vec<String>]) -> ark_bn254::G2Affine {
+    let c0 = fq_from_str(g2[0][0].clone());
+    let c1 = fq_from_str(g2[0][1].clone());
+    let x = ark_bn254::Fq2::new(c0, c1);
+
+    let c0 = fq_from_str(g2[1][0].clone());
+    let c1 = fq_from_str(g2[1][1].clone());
+    let y = ark_bn254::Fq2::new(c0, c1);
+
+    let c0 = fq_from_str(g2[2][0].clone());
+    let c1 = fq_from_str(g2[2][1].clone());
+    let z = ark_bn254::Fq2::new(c0, c1);
+
+    ark_bn254::G2Affine::from(ark_bn254::G2Projective::new(x, y, z))
+}
+
+fn value_to_string_vec(value: &Value) -> Vec<String> {
+    value
+        .as_array()
+        .unwrap()
+        .into_iter()
+        .map(|val| val.as_str().unwrap().to_string())
+        .collect()
+}
+
+#[test]
+fn test_groth16_proof_hardcoded() {
+    let tree_height = TEST_TREE_HEIGHT;
+
+    let rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    let valid_snarkjs_proof = json!({
+     "pi_a": [
+      "606446415626469993821291758185575230335423926365686267140465300918089871829",
+      "14881534001609371078663128199084130129622943308489025453376548677995646280161",
+      "1"
+     ],
+     "pi_b": [
+      [
+       "18053812507994813734583839134426913715767914942522332114506614735770984570178",
+       "11219916332635123001710279198522635266707985651975761715977705052386984005181"
+      ],
+      [
+       "17371289494006920912949790045699521359436706797224428511776122168520286372970",
+       "14038575727257298083893642903204723310279435927688342924358714639926373603890"
+      ],
+      [
+       "1",
+       "0"
+      ]
+     ],
+     "pi_c": [
+      "17701377127561410274754535747274973758826089226897242202671882899370780845888",
+      "12608543716397255084418384146504333522628400182843246910626782513289789807030",
+      "1"
+     ],
+     "protocol": "groth16",
+     "curve": "bn128"
+    });
+    let valid_ark_proof = ArkProof {
+        a: g1_from_str(&value_to_string_vec(&valid_snarkjs_proof["pi_a"])),
+        b: g2_from_str(
+            &valid_snarkjs_proof["pi_b"]
+                .as_array()
+                .unwrap()
+                .iter()
+                .map(|item| value_to_string_vec(item))
+                .collect::<Vec<Vec<String>>>(),
+        ),
+        c: g1_from_str(&value_to_string_vec(&valid_snarkjs_proof["pi_c"])),
+    };
+
+    let valid_proof_values = RLNProofValues {
+        x: str_to_fr(
+            "20645213238265527935869146898028115621427162613172918400241870500502509785943",
+            10,
+        )
+        .unwrap(),
+        external_nullifier: str_to_fr(
+            "21074405743803627666274838159589343934394162804826017440941339048886754734203",
+            10,
+        )
+        .unwrap(),
+        y: str_to_fr(
+            "16401008481486069296141645075505218976370369489687327284155463920202585288271",
+            10,
+        )
+        .unwrap(),
+        root: str_to_fr(
+            "8502402278351299594663821509741133196466235670407051417832304486953898514733",
+            10,
+        )
+        .unwrap(),
+        nullifier: str_to_fr(
+            "9102791780887227194595604713537772536258726662792598131262022534710887343694",
+            10,
+        )
+        .unwrap(),
+    };
+
+    let verified = verify_proof(&rln.verification_key, &valid_ark_proof, &valid_proof_values);
+    assert!(verified.unwrap());
+}
+
+#[test]
+// This test is similar to the one in lib, but uses only public API
+fn test_groth16_proof() {
+    let tree_height = TEST_TREE_HEIGHT;
+
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // Note: we only test Groth16 proof generation, so we ignore setting the tree in the RLN object
+    let rln_witness = random_rln_witness(tree_height);
+    let proof_values = proof_values_from_witness(&rln_witness).unwrap();
+
+    // We compute a Groth16 proof
+    let mut input_buffer = Cursor::new(serialize_witness(&rln_witness).unwrap());
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.prove(&mut input_buffer, &mut output_buffer).unwrap();
+    let serialized_proof = output_buffer.into_inner();
+
+    // Before checking public verify API, we check that the (deserialized) proof generated by prove is actually valid
+    let proof = ArkProof::deserialize_compressed(&mut Cursor::new(&serialized_proof)).unwrap();
+    let verified = verify_proof(&rln.verification_key, &proof, &proof_values);
+    // dbg!(verified.unwrap());
+    assert!(verified.unwrap());
+
+    // We prepare the input to prove API, consisting of serialized_proof (compressed, 4*32 bytes) || serialized_proof_values (6*32 bytes)
+    let serialized_proof_values = serialize_proof_values(&proof_values);
+    let mut verify_data = Vec::<u8>::new();
+    verify_data.extend(&serialized_proof);
+    verify_data.extend(&serialized_proof_values);
+    let mut input_buffer = Cursor::new(verify_data);
+
+    // We verify the Groth16 proof against the provided proof values
+    let verified = rln.verify(&mut input_buffer).unwrap();
+
+    assert!(verified);
+}
+
+#[test]
+fn test_rln_proof() {
+    let tree_height = TEST_TREE_HEIGHT;
+    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 = Fr::rand(&mut rng);
+        let rate_commitment = utils_poseidon_hash(&[id_commitment, Fr::from(100)]);
+        leaves.push(rate_commitment);
+    }
+
+    // We create a new RLN instance
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // Generate identity pair
+    let (identity_secret_hash, id_commitment) = keygen();
+
+    // We set as leaf rate_commitment after storing its index
+    let identity_index = rln.tree.leaves_set();
+    let user_message_limit = Fr::from(65535);
+    let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
+    let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
+    rln.set_next_leaf(&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 prepare input for generate_rln_proof API
+    let mut serialized: Vec<u8> = Vec::new();
+    serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
+    serialized.append(&mut normalize_usize(identity_index));
+    serialized.append(&mut fr_to_bytes_le(&user_message_limit));
+    serialized.append(&mut fr_to_bytes_le(&Fr::from(1)));
+    serialized.append(&mut fr_to_bytes_le(&utils_poseidon_hash(&[
+        epoch,
+        rln_identifier,
+    ])));
+    serialized.append(&mut normalize_usize(signal.len()));
+    serialized.append(&mut signal.to_vec());
+
+    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();
+
+    // output_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+    let mut proof_data = output_buffer.into_inner();
+
+    // We prepare input for verify_rln_proof API
+    // input_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
+    // that is [ proof_data || signal_len<8> | signal<var> ]
+    proof_data.append(&mut normalize_usize(signal.len()));
+    proof_data.append(&mut signal.to_vec());
+
+    let mut input_buffer = Cursor::new(proof_data);
+    let verified = rln.verify_rln_proof(&mut input_buffer).unwrap();
+
+    assert!(verified);
+}
+
+#[test]
+fn test_rln_with_witness() {
+    let tree_height = TEST_TREE_HEIGHT;
+    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 {
+        leaves.push(Fr::rand(&mut rng));
+    }
+
+    // We create a new RLN instance
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // Generate identity pair
+    let (identity_secret_hash, id_commitment) = keygen();
+
+    // We set as leaf rate_commitment after storing its index
+    let identity_index = rln.tree.leaves_set();
+    let user_message_limit = Fr::from(100);
+    let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
+    let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
+    rln.set_next_leaf(&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 prepare input for generate_rln_proof API
+    // input_data is [ identity_secret<32> | id_index<8> | epoch<32> | signal_len<8> | signal<var> ]
+    let mut serialized: Vec<u8> = Vec::new();
+    serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
+    serialized.append(&mut normalize_usize(identity_index));
+    serialized.append(&mut fr_to_bytes_le(&user_message_limit));
+    serialized.append(&mut fr_to_bytes_le(&Fr::from(1)));
+    serialized.append(&mut fr_to_bytes_le(&utils_poseidon_hash(&[
+        epoch,
+        rln_identifier,
+    ])));
+    serialized.append(&mut normalize_usize(signal.len()));
+    serialized.append(&mut signal.to_vec());
+
+    let mut input_buffer = Cursor::new(serialized);
+
+    // We read input RLN witness and we serialize_compressed it
+    let mut witness_byte: Vec<u8> = Vec::new();
+    input_buffer.read_to_end(&mut witness_byte).unwrap();
+    let (rln_witness, _) = proof_inputs_to_rln_witness(&mut rln.tree, &witness_byte).unwrap();
+
+    let serialized_witness = serialize_witness(&rln_witness).unwrap();
+
+    // Calculate witness outside zerokit (simulating what JS is doing)
+    let inputs = inputs_for_witness_calculation(&rln_witness)
+        .unwrap()
+        .into_iter()
+        .map(|(name, values)| (name.to_string(), values));
+    let calculated_witness = rln
+        .witness_calculator
+        .lock()
+        .expect("witness_calculator mutex should not get poisoned")
+        .calculate_witness_element::<Curve, _>(inputs, false)
+        .map_err(ProofError::WitnessError)
+        .unwrap();
+
+    let calculated_witness_vec: Vec<BigInt> = calculated_witness
+        .into_iter()
+        .map(|v| to_bigint(&v).unwrap())
+        .collect();
+
+    // Generating the proof
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.generate_rln_proof_with_witness(
+        calculated_witness_vec,
+        serialized_witness,
+        &mut output_buffer,
+    )
+    .unwrap();
+
+    // output_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+    let mut proof_data = output_buffer.into_inner();
+
+    // We prepare input for verify_rln_proof API
+    // input_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
+    // that is [ proof_data || signal_len<8> | signal<var> ]
+    proof_data.append(&mut normalize_usize(signal.len()));
+    proof_data.append(&mut signal.to_vec());
+
+    let mut input_buffer = Cursor::new(proof_data);
+    let verified = rln.verify_rln_proof(&mut input_buffer).unwrap();
+
+    assert!(verified);
+}
+
+#[test]
+fn proof_verification_with_roots() {
+    // The first part is similar to test_rln_with_witness
+    let tree_height = TEST_TREE_HEIGHT;
+    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 {
+        leaves.push(Fr::rand(&mut rng));
+    }
+
+    // We create a new RLN instance
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We add leaves in a batch into the tree
+    let mut buffer = Cursor::new(vec_fr_to_bytes_le(&leaves).unwrap());
+    rln.init_tree_with_leaves(&mut buffer).unwrap();
+
+    // Generate identity pair
+    let (identity_secret_hash, id_commitment) = keygen();
+
+    // We set as leaf id_commitment after storing its index
+    let identity_index = rln.tree.leaves_set();
+    let user_message_limit = Fr::from(100);
+    let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
+    let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
+    rln.set_next_leaf(&mut buffer).unwrap();
+
+    // We generate a random signal
+    let mut rng = thread_rng();
+    let signal: [u8; 32] = rng.gen();
+
+    // We generate a random epoch
+    let epoch = hash_to_field(b"test-epoch");
+    // We generate a random rln_identifier
+    let rln_identifier = hash_to_field(b"test-rln-identifier");
+    let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
+
+    // We prepare input for generate_rln_proof API
+    // input_data is [ identity_secret<32> | id_index<8> | external_nullifier<32> | user_message_limit<32> | message_id<32> | signal_len<8> | signal<var> ]
+    let mut serialized: Vec<u8> = Vec::new();
+    serialized.append(&mut fr_to_bytes_le(&identity_secret_hash));
+    serialized.append(&mut normalize_usize(identity_index));
+    serialized.append(&mut fr_to_bytes_le(&user_message_limit));
+    serialized.append(&mut fr_to_bytes_le(&Fr::from(1)));
+    serialized.append(&mut fr_to_bytes_le(&external_nullifier));
+    serialized.append(&mut normalize_usize(signal.len()));
+    serialized.append(&mut signal.to_vec());
+
+    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();
+
+    // output_data is  [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> ]
+    let mut proof_data = output_buffer.into_inner();
+
+    // We prepare input for verify_rln_proof API
+    // input_data is [ proof<128> | root<32> | external_nullifier<32> | x<32> | y<32> | nullifier<32> | signal_len<8> | signal<var> ]
+    // that is [ proof_data || signal_len<8> | signal<var> ]
+    proof_data.append(&mut normalize_usize(signal.len()));
+    proof_data.append(&mut signal.to_vec());
+    let input_buffer = Cursor::new(proof_data);
+
+    // If no roots is provided, proof validation is skipped and if the remaining proof values are valid, the proof will be correctly verified
+    let mut roots_serialized: Vec<u8> = Vec::new();
+    let mut roots_buffer = Cursor::new(roots_serialized.clone());
+    let verified = rln
+        .verify_with_roots(&mut input_buffer.clone(), &mut roots_buffer)
+        .unwrap();
+
+    assert!(verified);
+
+    // We serialize in the roots buffer some random values and we check that the proof is not verified since doesn't contain the correct root the proof refers to
+    for _ in 0..5 {
+        roots_serialized.append(&mut fr_to_bytes_le(&Fr::rand(&mut rng)));
+    }
+    roots_buffer = Cursor::new(roots_serialized.clone());
+    let verified = rln
+        .verify_with_roots(&mut input_buffer.clone(), &mut roots_buffer)
+        .unwrap();
+
+    assert_eq!(verified, false);
+
+    // We get the root of the tree obtained adding one leaf per time
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_root(&mut buffer).unwrap();
+    let (root, _) = bytes_le_to_fr(&buffer.into_inner());
+
+    // We add the real root and we check if now the proof is verified
+    roots_serialized.append(&mut fr_to_bytes_le(&root));
+    roots_buffer = Cursor::new(roots_serialized.clone());
+    let verified = rln
+        .verify_with_roots(&mut input_buffer.clone(), &mut roots_buffer)
+        .unwrap();
+
+    assert!(verified);
+}
+
+#[test]
+fn test_recover_id_secret() {
+    let tree_height = TEST_TREE_HEIGHT;
+
+    // We create a new RLN instance
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // Generate identity pair
+    let (identity_secret_hash, id_commitment) = keygen();
+    let user_message_limit = Fr::from(100);
+    let message_id = Fr::from(0);
+    let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
+
+    // We set as leaf id_commitment after storing its index
+    let identity_index = rln.tree.leaves_set();
+    let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
+    rln.set_next_leaf(&mut buffer).unwrap();
+
+    // We generate two random signals
+    let mut rng = rand::thread_rng();
+    let signal1: [u8; 32] = rng.gen();
+
+    let signal2: [u8; 32] = rng.gen();
+
+    // We generate a random epoch
+    let epoch = hash_to_field(b"test-epoch");
+    // We generate a random rln_identifier
+    let rln_identifier = hash_to_field(b"test-rln-identifier");
+    let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
+
+    // We generate two proofs using same epoch but different signals.
+
+    // We prepare input for generate_rln_proof API
+    let mut serialized1: Vec<u8> = Vec::new();
+    serialized1.append(&mut fr_to_bytes_le(&identity_secret_hash));
+    serialized1.append(&mut normalize_usize(identity_index));
+    serialized1.append(&mut fr_to_bytes_le(&user_message_limit));
+    serialized1.append(&mut fr_to_bytes_le(&message_id));
+    serialized1.append(&mut fr_to_bytes_le(&external_nullifier));
+
+    // The first part is the same for both proof input, so we clone
+    let mut serialized2 = serialized1.clone();
+
+    // We attach the first signal to the first proof input
+    serialized1.append(&mut normalize_usize(signal1.len()));
+    serialized1.append(&mut signal1.to_vec());
+
+    // We attach the second signal to the first proof input
+    serialized2.append(&mut normalize_usize(signal2.len()));
+    serialized2.append(&mut signal2.to_vec());
+
+    // We generate the first proof
+    let mut input_buffer = Cursor::new(serialized1);
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
+        .unwrap();
+    let proof_data_1 = output_buffer.into_inner();
+
+    // We generate the second proof
+    let mut input_buffer = Cursor::new(serialized2);
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
+        .unwrap();
+    let proof_data_2 = output_buffer.into_inner();
+
+    let mut input_proof_data_1 = Cursor::new(proof_data_1.clone());
+    let mut input_proof_data_2 = Cursor::new(proof_data_2);
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.recover_id_secret(
+        &mut input_proof_data_1,
+        &mut input_proof_data_2,
+        &mut output_buffer,
+    )
+    .unwrap();
+
+    let serialized_identity_secret_hash = output_buffer.into_inner();
+
+    // We ensure that a non-empty value is written to output_buffer
+    assert!(!serialized_identity_secret_hash.is_empty());
+
+    // We check if the recovered identity secret hash corresponds to the original one
+    let (recovered_identity_secret_hash, _) = bytes_le_to_fr(&serialized_identity_secret_hash);
+    assert_eq!(recovered_identity_secret_hash, identity_secret_hash);
+
+    // We now test that computing identity_secret_hash is unsuccessful if shares computed from two different identity secret hashes but within same epoch are passed
+
+    // We generate a new identity pair
+    let (identity_secret_hash_new, id_commitment_new) = keygen();
+    let rate_commitment_new = utils_poseidon_hash(&[id_commitment_new, user_message_limit]);
+
+    // We add it to the tree
+    let identity_index_new = rln.tree.leaves_set();
+    let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment_new));
+    rln.set_next_leaf(&mut buffer).unwrap();
+
+    // We generate a random signals
+    let signal3: [u8; 32] = rng.gen();
+
+    // We prepare proof input. Note that epoch is the same as before
+    let mut serialized3: Vec<u8> = Vec::new();
+    serialized3.append(&mut fr_to_bytes_le(&identity_secret_hash_new));
+    serialized3.append(&mut normalize_usize(identity_index_new));
+    serialized3.append(&mut fr_to_bytes_le(&user_message_limit));
+    serialized3.append(&mut fr_to_bytes_le(&message_id));
+    serialized3.append(&mut fr_to_bytes_le(&external_nullifier));
+    serialized3.append(&mut normalize_usize(signal3.len()));
+    serialized3.append(&mut signal3.to_vec());
+
+    // We generate the proof
+    let mut input_buffer = Cursor::new(serialized3);
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.generate_rln_proof(&mut input_buffer, &mut output_buffer)
+        .unwrap();
+    let proof_data_3 = output_buffer.into_inner();
+
+    // We attempt to recover the secret using share1 (coming from identity_secret_hash) and share3 (coming from identity_secret_hash_new)
+
+    let mut input_proof_data_1 = Cursor::new(proof_data_1.clone());
+    let mut input_proof_data_3 = Cursor::new(proof_data_3);
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.recover_id_secret(
+        &mut input_proof_data_1,
+        &mut input_proof_data_3,
+        &mut output_buffer,
+    )
+    .unwrap();
+
+    let serialized_identity_secret_hash = output_buffer.into_inner();
+    let (recovered_identity_secret_hash_new, _) = bytes_le_to_fr(&serialized_identity_secret_hash);
+
+    // ensure that the recovered secret does not match with either of the
+    // used secrets in proof generation
+    assert_ne!(recovered_identity_secret_hash_new, identity_secret_hash_new);
+}
+
+#[test]
+fn test_get_leaf() {
+    // We generate a random tree
+    let tree_height = 10;
+    let mut rng = thread_rng();
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    // We generate a random leaf
+    let leaf = Fr::rand(&mut rng);
+
+    // We generate a random index
+    let index = rng.gen_range(0..rln.tree.capacity());
+
+    // We add the leaf to the tree
+    let mut buffer = Cursor::new(fr_to_bytes_le(&leaf));
+    rln.set_leaf(index, &mut buffer).unwrap();
+
+    // We get the leaf
+    let mut output_buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_leaf(index, &mut output_buffer).unwrap();
+
+    // We ensure that the leaf is the same as the one we added
+    let (received_leaf, _) = bytes_le_to_fr(output_buffer.into_inner().as_ref());
+    assert_eq!(received_leaf, leaf);
+}
+
+#[test]
+fn test_valid_metadata() {
+    let tree_height = TEST_TREE_HEIGHT;
+
+    let mut rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    let arbitrary_metadata: &[u8] = b"block_number:200000";
+    rln.set_metadata(arbitrary_metadata).unwrap();
+
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_metadata(&mut buffer).unwrap();
+    let received_metadata = buffer.into_inner();
+
+    assert_eq!(arbitrary_metadata, received_metadata);
+}
+
+#[test]
+fn test_empty_metadata() {
+    let tree_height = TEST_TREE_HEIGHT;
+
+    let rln = RLN::new(tree_height, generate_input_buffer()).unwrap();
+
+    let mut buffer = Cursor::new(Vec::<u8>::new());
+    rln.get_metadata(&mut buffer).unwrap();
+    let received_metadata = buffer.into_inner();
+
+    assert_eq!(received_metadata.len(), 0);
+}

rln/src/utils.rs

@@ -5,10 +5,12 @@ use ark_ff::PrimeField;
 use color_eyre::{Report, Result};
 use num_bigint::{BigInt, BigUint};
 use num_traits::Num;
+use serde_json::json;
+use std::io::Cursor;
 use std::iter::Extend;
 
 pub fn to_bigint(el: &Fr) -> Result<BigInt> {
-    let res: BigUint = (*el).try_into()?;
+    let res: BigUint = (*el).into();
     Ok(res.into())
 }
 
@@ -28,10 +30,10 @@ pub fn str_to_fr(input: &str, radix: u32) -> Result<Fr> {
     input_clean = input_clean.trim().to_string();
 
     if radix == 10 {
-        Ok(BigUint::from_str_radix(&input_clean, radix)?.try_into()?)
+        Ok(BigUint::from_str_radix(&input_clean, radix)?.into())
     } else {
         input_clean = input_clean.replace("0x", "");
-        Ok(BigUint::from_str_radix(&input_clean, radix)?.try_into()?)
+        Ok(BigUint::from_str_radix(&input_clean, radix)?.into())
     }
 }
 
@@ -179,6 +181,24 @@ pub fn normalize_usize(input: usize) -> Vec<u8> {
     normalized_usize
 }
 
+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 elements: Vec<usize> = input[8..]
+            .chunks(8)
+            .map(|ch| usize::from_le_bytes(ch[0..8].try_into().unwrap()))
+            .collect();
+        Ok(elements)
+    }
+}
+
+// using for test
+pub fn generate_input_buffer() -> Cursor<String> {
+    Cursor::new(json!({}).to_string())
+}
+
 /* Old conversion utilities between different libraries data types
 
 // Conversion Utilities between poseidon-rs Field and arkworks Fr (in order to call directly poseidon-rs' poseidon_hash)

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

@@ -1,9 +1,8 @@
 #[cfg(test)]
 mod test {
-    use rln::circuit::{
-        circom_from_folder, vk_from_folder, zkey_from_folder, Fr, TEST_RESOURCES_FOLDER,
-        TEST_TREE_HEIGHT,
-    };
+    use ark_ff::BigInt;
+    use rln::circuit::zkey_from_folder;
+    use rln::circuit::{circom_from_folder, vk_from_folder, Fr, TEST_TREE_HEIGHT};
     use rln::hashers::{hash_to_field, poseidon_hash};
     use rln::poseidon_tree::PoseidonTree;
     use rln::protocol::*;
@@ -12,365 +11,135 @@ mod test {
 
     type ConfigOf<T> = <T as ZerokitMerkleTree>::Config;
 
-    // Input generated with https://github.com/oskarth/zk-kit/commit/b6a872f7160c7c14e10a0ea40acab99cbb23c9a8
-    const WITNESS_JSON_15: &str = r#"
-            {
-              "identity_secret": "12825549237505733615964533204745049909430608936689388901883576945030025938736",
-              "path_elements": [
-                "18622655742232062119094611065896226799484910997537830749762961454045300666333",
-                "20590447254980891299813706518821659736846425329007960381537122689749540452732",
-                "7423237065226347324353380772367382631490014989348495481811164164159255474657",
-                "11286972368698509976183087595462810875513684078608517520839298933882497716792",
-                "3607627140608796879659380071776844901612302623152076817094415224584923813162",
-                "19712377064642672829441595136074946683621277828620209496774504837737984048981",
-                "20775607673010627194014556968476266066927294572720319469184847051418138353016",
-                "3396914609616007258851405644437304192397291162432396347162513310381425243293",
-                "21551820661461729022865262380882070649935529853313286572328683688269863701601",
-                "6573136701248752079028194407151022595060682063033565181951145966236778420039",
-                "12413880268183407374852357075976609371175688755676981206018884971008854919922",
-                "14271763308400718165336499097156975241954733520325982997864342600795471836726",
-                "20066985985293572387227381049700832219069292839614107140851619262827735677018",
-                "9394776414966240069580838672673694685292165040808226440647796406499139370960",
-                "11331146992410411304059858900317123658895005918277453009197229807340014528524"
-              ],
-              "identity_path_index": [
-                1,
-                1,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0,
-                0
-              ],
-              "x": "8143228284048792769012135629627737459844825626241842423967352803501040982",
-              "epoch": "0x0000005b612540fc986b42322f8cb91c2273afad58ed006fdba0c97b4b16b12f",
-              "rln_identifier": "11412926387081627876309792396682864042420635853496105400039841573530884328439"
-            }
-        "#;
-
-    // Input generated with protocol::random_rln_witness
-    const WITNESS_JSON_19: &str = r#"
-            {
-              "identity_secret": "922538810348594125658702672067738675294669207539999802857585668079702330450",
-              "path_elements": [
-                  "16059714054680148404543504061485737353203416489071538960876865983954285286166",
-                  "3041470753871943901334053763207316028823782848445723460227667780327106380356",
-                  "2557297527793326315072058421057853700096944625924483912548759909801348042183",
-                  "6677578602456189582427063963562590713054668181987223110955234085327917303436",
-                  "2250827150965576973906150764756422151438812678308727218463995574869267980301",
-                  "1895457427602709606993445561553433669787657053834360973759981803464906070980",
-                  "11033689991077061346803816826729204895841441316315304395980565540264104346466",
-                  "18588752216879570844240300406954267039026327526134910835334500497981810174976",
-                  "19346480964028499661277403659363466542857230928032088490855656809181891953123",
-                  "21460193770370072688835316363068413651465631481105148051902686770759127189327",
-                  "20906347653364838502964722817589315918082261023317339146393355650507243340078",
-                  "13466599592974387800162739317046838825289754472645703919149409009404541432954",
-                  "9617165663598957201253074168824246164494443748556931540348223968573884172285",
-                  "6936463137584425684797785981770877165377386163416057257854261010817156666898",
-                  "369902028235468424790098825415813437044876310542601948037281422841675126849",
-                  "13510969869821080499683463562609720931680005714401083864659516045615497273644",
-                  "2567921390740781421487331055530491683313154421589525170472201828596388395736",
-                  "14360870889466292805403568662660511177232987619663547772298178013674025998478",
-                  "4735344599616284973799984501493858013178071155960162022656706545116168334293"
-              ],
-              "identity_path_index": [
-                  1,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0
-              ],
-              "x": "6427050788896290028100534859169645070970780055911091444144195464808120686416",
-              "epoch": "0x2bd155d9f85c741044da6909d144f9cc5ce8e0d545a9ed4921b156e8b8569bab",
-              "rln_identifier": "2193983000213424579594329476781986065965849144986973472766961413131458022566"
-            }
-        "#;
-
-    const WITNESS_JSON_20: &str = r#"
-            {
-              "identity_secret": "13732353453861280511150022598793312186188599006979552959297495195757997428306",
-              "path_elements": [
-                  "20463525608687844300981085488128968694844212760055234622292326942405619575964",
-                  "8040856403709217901175408904825741112286158901303127670929462145501210871313",
-                  "3776499751255585163563840252112871568402966629435152937692711318702338789837",
-                  "19415813252626942110541463414404411443562242499365750694284604341271149125679",
-                  "19414720788761208006634240390286942738242262010168559813148115573784354129237",
-                  "17680594732844291740094158892269696200077963275550625226493856898849422516043",
-                  "16009199741350632715210088346611798597033333293348807000623441780059543674510",
-                  "18743496911007535170857676824393811326863602477260615792503039058813338644738",
-                  "1029572792321380246989475723806770724699749375691788486434716005338938722216",
-                  "21713138150151063186050010182615713685603650963220209951496401043119768920892",
-                  "6713732504049401389983008178456811894856018247924860823028704114266363984580",
-                  "2746686888799473963221285145390361693256731812094259845879519459924507786594",
-                  "18620748467731297359505500266677881218553438497271819903304075323783392031715",
-                  "2446201221122671119406471414204229600430018713181038717206670749886932158104",
-                  "12037171942017611311954851302868199608036334625783560875426350283156617524597",
-                  "21798743392351780927808323348278035105395367759688979232116905142049921734349",
-                  "17450230289417496971557215666910229260621413088991137405744457922069827319039",
-                  "20936854099128086256353520300046664152516566958630447858438908748907198510485",
-                  "13513344965831154386658059617477268600255664386844920822248038939666265737046",
-                  "15546319496880899251450021422131511560001766832580480193115646510655765306630"
-
-              ],
-              "identity_path_index": [
-                  0,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0,
-                  1,
-                  0,
-                  1,
-                  1,
-                  0,
-                  0,
-                  0
-              ],
-              "x": "18073935665561339809445069958310044423750771681863480888589546877024349720547",
-              "epoch": "0x147e4c23a43a1ddca78d94bcd28147f62ca74b3dc7e56bb0a314a954b9f0e567",
-              "rln_identifier": "2193983000213424579594329476781986065965849144986973472766961413131458022566"
-            }
-        "#;
-
     #[test]
     // We test Merkle tree generation, proofs and verification
     fn test_merkle_proof() {
-        let tree_height = TEST_TREE_HEIGHT;
         let leaf_index = 3;
 
         // generate identity
         let identity_secret_hash = hash_to_field(b"test-merkle-proof");
-        let id_commitment = poseidon_hash(&vec![identity_secret_hash]);
+        let id_commitment = poseidon_hash(&[identity_secret_hash]);
+        let rate_commitment = poseidon_hash(&[id_commitment, 100.into()]);
 
         // generate merkle tree
         let default_leaf = Fr::from(0);
         let mut tree = PoseidonTree::new(
-            tree_height,
+            TEST_TREE_HEIGHT,
             default_leaf,
             ConfigOf::<PoseidonTree>::default(),
         )
         .unwrap();
-        tree.set(leaf_index, id_commitment.into()).unwrap();
+        tree.set(leaf_index, rate_commitment.into()).unwrap();
 
         // We check correct computation of the root
         let root = tree.root();
 
-        if TEST_TREE_HEIGHT == 15 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x1984f2e01184aef5cb974640898a5f5c25556554e2b06d99d4841badb8b198cd",
-                    16
-                )
-                .unwrap()
-            );
-        } else if TEST_TREE_HEIGHT == 19 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x219ceb53f2b1b7a6cf74e80d50d44d68ecb4a53c6cc65b25593c8d56343fb1fe",
-                    16
-                )
-                .unwrap()
-            );
-        } else if TEST_TREE_HEIGHT == 20 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x21947ffd0bce0c385f876e7c97d6a42eec5b1fe935aab2f01c1f8a8cbcc356d2",
-                    16
-                )
-                .unwrap()
-            );
-        }
+        assert_eq!(
+            root,
+            BigInt([
+                4939322235247991215,
+                5110804094006647505,
+                4427606543677101242,
+                910933464535675827
+            ])
+            .into()
+        );
 
         let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
         let path_elements = merkle_proof.get_path_elements();
         let identity_path_index = merkle_proof.get_path_index();
 
         // We check correct computation of the path and indexes
-        // These values refers to TEST_TREE_HEIGHT == 16
-        let mut expected_path_elements = vec![
-            str_to_fr(
-                "0x0000000000000000000000000000000000000000000000000000000000000000",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
-                16,
-            )
-            .unwrap(),
-        ];
+        let expected_path_elements: Vec<Fr> = [
+            "0x0000000000000000000000000000000000000000000000000000000000000000",
+            "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
+            "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
+            "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
+            "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
+            "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
+            "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
+            "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
+            "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
+            "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
+            "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
+            "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
+            "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
+            "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
+            "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
+            "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
+            "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
+            "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
+            "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
+            "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
+        ]
+        .map(|e| str_to_fr(e, 16).unwrap())
+        .to_vec();
 
-        let mut expected_identity_path_index: Vec<u8> =
-            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
-
-        // We add the remaining elements for the case TEST_TREE_HEIGHT = 20
-        if TEST_TREE_HEIGHT == 19 || TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![
-                str_to_fr(
-                    "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
-                    16,
-                )
-                .unwrap(),
-            ]);
-            expected_identity_path_index.append(&mut vec![0, 0, 0, 0]);
-        }
-
-        if TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![str_to_fr(
-                "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
-                16,
-            )
-            .unwrap()]);
-            expected_identity_path_index.append(&mut vec![0]);
-        }
+        let expected_identity_path_index: Vec<u8> =
+            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
 
         assert_eq!(path_elements, expected_path_elements);
         assert_eq!(identity_path_index, expected_identity_path_index);
 
         // We check correct verification of the proof
-        assert!(tree.verify(&id_commitment, &merkle_proof).unwrap());
+        assert!(tree.verify(&rate_commitment, &merkle_proof).unwrap());
+    }
+
+    fn get_test_witness() -> RLNWitnessInput {
+        let leaf_index = 3;
+        // Generate identity pair
+        let (identity_secret_hash, id_commitment) = keygen();
+        let user_message_limit = Fr::from(100);
+        let rate_commitment = poseidon_hash(&[id_commitment, user_message_limit]);
+
+        //// generate merkle tree
+        let default_leaf = Fr::from(0);
+        let mut tree = PoseidonTree::new(
+            TEST_TREE_HEIGHT,
+            default_leaf,
+            ConfigOf::<PoseidonTree>::default(),
+        )
+        .unwrap();
+        tree.set(leaf_index, rate_commitment.into()).unwrap();
+
+        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
+
+        let signal = b"hey hey";
+        let x = hash_to_field(signal);
+
+        // We set the remaining values to random ones
+        let epoch = hash_to_field(b"test-epoch");
+        let rln_identifier = hash_to_field(b"test-rln-identifier");
+        let external_nullifier = poseidon_hash(&[epoch, rln_identifier]);
+
+        rln_witness_from_values(
+            identity_secret_hash,
+            &merkle_proof,
+            x,
+            external_nullifier,
+            user_message_limit,
+            Fr::from(1),
+        )
+        .unwrap()
     }
 
     #[test]
     // We test a RLN proof generation and verification
     fn test_witness_from_json() {
         // We generate all relevant keys
-        let proving_key = zkey_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let verification_key = vk_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let builder = circom_from_folder(TEST_RESOURCES_FOLDER).unwrap();
+        let proving_key = zkey_from_folder().unwrap();
+        let verification_key = vk_from_folder().unwrap();
+        let builder = circom_from_folder().unwrap();
 
-        // We compute witness from the json input example
-        let mut witness_json: &str = "";
-
-        if TEST_TREE_HEIGHT == 15 {
-            witness_json = WITNESS_JSON_15;
-        } else if TEST_TREE_HEIGHT == 19 {
-            witness_json = WITNESS_JSON_19;
-        } else if TEST_TREE_HEIGHT == 20 {
-            witness_json = WITNESS_JSON_20;
-        }
-
-        let rln_witness = rln_witness_from_json(witness_json);
-
-        let rln_witness_unwrapped = rln_witness.unwrap();
+        // We compute witness from the json input
+        let rln_witness = get_test_witness();
+        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
+        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
+        assert_eq!(rln_witness_deser, rln_witness);
 
         // Let's generate a zkSNARK proof
-        let proof = generate_proof(builder, &proving_key, &rln_witness_unwrapped).unwrap();
-
-        let proof_values = proof_values_from_witness(&rln_witness_unwrapped);
+        let proof = generate_proof(builder, &proving_key, &rln_witness_deser).unwrap();
+        let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();
 
         // Let's verify the proof
         let verified = verify_proof(&verification_key, &proof, &proof_values);
@@ -381,47 +150,20 @@ mod test {
     #[test]
     // We test a RLN proof generation and verification
     fn test_end_to_end() {
-        let tree_height = TEST_TREE_HEIGHT;
-        let leaf_index = 3;
-
-        // Generate identity pair
-        let (identity_secret_hash, id_commitment) = keygen();
-
-        //// generate merkle tree
-        let default_leaf = Fr::from(0);
-        let mut tree = PoseidonTree::new(
-            tree_height,
-            default_leaf,
-            ConfigOf::<PoseidonTree>::default(),
-        )
-        .unwrap();
-        tree.set(leaf_index, id_commitment.into()).unwrap();
-
-        let merkle_proof = tree.proof(leaf_index).expect("proof should exist");
-
-        let signal = b"hey hey";
-        let x = hash_to_field(signal);
-
-        // We set the remaining values to random ones
-        let epoch = hash_to_field(b"test-epoch");
-        //let rln_identifier = hash_to_field(b"test-rln-identifier");
-
-        let rln_witness: RLNWitnessInput = rln_witness_from_values(
-            identity_secret_hash,
-            &merkle_proof,
-            x,
-            epoch, /*, rln_identifier*/
-        );
+        let rln_witness = get_test_witness();
+        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
+        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
+        assert_eq!(rln_witness_deser, rln_witness);
 
         // We generate all relevant keys
-        let proving_key = zkey_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let verification_key = vk_from_folder(TEST_RESOURCES_FOLDER).unwrap();
-        let builder = circom_from_folder(TEST_RESOURCES_FOLDER).unwrap();
+        let proving_key = zkey_from_folder().unwrap();
+        let verification_key = vk_from_folder().unwrap();
+        let builder = circom_from_folder().unwrap();
 
         // Let's generate a zkSNARK proof
-        let proof = generate_proof(builder, &proving_key, &rln_witness).unwrap();
+        let proof = generate_proof(builder, &proving_key, &rln_witness_deser).unwrap();
 
-        let proof_values = proof_values_from_witness(&rln_witness);
+        let proof_values = proof_values_from_witness(&rln_witness_deser).unwrap();
 
         // Let's verify the proof
         let success = verify_proof(&verification_key, &proof, &proof_values).unwrap();
@@ -431,25 +173,19 @@ mod test {
 
     #[test]
     fn test_witness_serialization() {
+        // We test witness JSON serialization
+        let rln_witness = get_test_witness();
+        let rln_witness_json = rln_witness_to_json(&rln_witness).unwrap();
+        let rln_witness_deser = rln_witness_from_json(rln_witness_json).unwrap();
+        assert_eq!(rln_witness_deser, rln_witness);
+
         // We test witness serialization
-        let mut witness_json: &str = "";
-
-        if TEST_TREE_HEIGHT == 15 {
-            witness_json = WITNESS_JSON_15;
-        } else if TEST_TREE_HEIGHT == 19 {
-            witness_json = WITNESS_JSON_19;
-        } else if TEST_TREE_HEIGHT == 20 {
-            witness_json = WITNESS_JSON_20;
-        }
-
-        let rln_witness = rln_witness_from_json(witness_json).unwrap();
-
         let ser = serialize_witness(&rln_witness).unwrap();
         let (deser, _) = deserialize_witness(&ser).unwrap();
         assert_eq!(rln_witness, deser);
 
         // We test Proof values serialization
-        let proof_values = proof_values_from_witness(&rln_witness);
+        let proof_values = proof_values_from_witness(&rln_witness).unwrap();
         let ser = serialize_proof_values(&proof_values);
         let (deser, _) = deserialize_proof_values(&ser);
         assert_eq!(proof_values, deser);

rln/tests/public.rs

@@ -1,66 +1,58 @@
 #[cfg(test)]
 mod test {
+    use ark_ff::BigInt;
     use ark_std::{rand::thread_rng, UniformRand};
     use rand::Rng;
-    use rln::circuit::{Fr, TEST_RESOURCES_FOLDER, TEST_TREE_HEIGHT};
+    use rln::circuit::{Fr, TEST_TREE_HEIGHT};
     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::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
     fn test_merkle_proof() {
-        let tree_height = TEST_TREE_HEIGHT;
         let leaf_index = 3;
+        let user_message_limit = 1;
 
-        let input_buffer =
-            Cursor::new(json!({ "resources_folder": TEST_RESOURCES_FOLDER }).to_string());
-        let mut rln = RLN::new(tree_height, input_buffer).unwrap();
+        let mut rln = RLN::new(TEST_TREE_HEIGHT, generate_input_buffer()).unwrap();
 
         // generate identity
         let identity_secret_hash = hash_to_field(b"test-merkle-proof");
         let id_commitment = utils_poseidon_hash(&vec![identity_secret_hash]);
+        let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit.into()]);
 
-        // We pass id_commitment as Read buffer to RLN's set_leaf
-        let mut buffer = Cursor::new(fr_to_bytes_le(&id_commitment));
+        // check that leaves indices is empty
+        let mut buffer = Cursor::new(Vec::<u8>::new());
+        rln.get_empty_leaves_indices(&mut buffer).unwrap();
+        let idxs = bytes_le_to_vec_usize(&buffer.into_inner()).unwrap();
+        assert!(idxs.is_empty());
+
+        // We pass rate_commitment as Read buffer to RLN's set_leaf
+        let mut buffer = Cursor::new(fr_to_bytes_le(&rate_commitment));
         rln.set_leaf(leaf_index, &mut buffer).unwrap();
 
+        // check that leaves before leaf_index is set to zero
+        let mut buffer = Cursor::new(Vec::<u8>::new());
+        rln.get_empty_leaves_indices(&mut buffer).unwrap();
+        let idxs = bytes_le_to_vec_usize(&buffer.into_inner()).unwrap();
+        assert_eq!(idxs, [0, 1, 2]);
+
         // We check correct computation of the root
         let mut buffer = Cursor::new(Vec::<u8>::new());
         rln.get_root(&mut buffer).unwrap();
         let (root, _) = bytes_le_to_fr(&buffer.into_inner());
 
-        if TEST_TREE_HEIGHT == 15 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x1984f2e01184aef5cb974640898a5f5c25556554e2b06d99d4841badb8b198cd",
-                    16
-                )
-                .unwrap()
-            );
-        } else if TEST_TREE_HEIGHT == 19 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x219ceb53f2b1b7a6cf74e80d50d44d68ecb4a53c6cc65b25593c8d56343fb1fe",
-                    16
-                )
-                .unwrap()
-            );
-        } else if TEST_TREE_HEIGHT == 20 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x21947ffd0bce0c385f876e7c97d6a42eec5b1fe935aab2f01c1f8a8cbcc356d2",
-                    16
-                )
-                .unwrap()
-            );
-        }
+        assert_eq!(
+            root,
+            Fr::from(BigInt([
+                17110646155607829651,
+                5040045984242729823,
+                6965416728592533086,
+                2328960363755461975
+            ]))
+        );
 
         // We check correct computation of merkle proof
         let mut buffer = Cursor::new(Vec::<u8>::new());
@@ -71,129 +63,67 @@ mod test {
         let (identity_path_index, _) = bytes_le_to_vec_u8(&buffer_inner[read..].to_vec()).unwrap();
 
         // We check correct computation of the path and indexes
-        let mut expected_path_elements = vec![
-            str_to_fr(
-                "0x0000000000000000000000000000000000000000000000000000000000000000",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
-                16,
-            )
-            .unwrap(),
-            str_to_fr(
-                "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
-                16,
-            )
-            .unwrap(),
-        ];
+        let expected_path_elements: Vec<Fr> = [
+            "0x0000000000000000000000000000000000000000000000000000000000000000",
+            "0x2098f5fb9e239eab3ceac3f27b81e481dc3124d55ffed523a839ee8446b64864",
+            "0x1069673dcdb12263df301a6ff584a7ec261a44cb9dc68df067a4774460b1f1e1",
+            "0x18f43331537ee2af2e3d758d50f72106467c6eea50371dd528d57eb2b856d238",
+            "0x07f9d837cb17b0d36320ffe93ba52345f1b728571a568265caac97559dbc952a",
+            "0x2b94cf5e8746b3f5c9631f4c5df32907a699c58c94b2ad4d7b5cec1639183f55",
+            "0x2dee93c5a666459646ea7d22cca9e1bcfed71e6951b953611d11dda32ea09d78",
+            "0x078295e5a22b84e982cf601eb639597b8b0515a88cb5ac7fa8a4aabe3c87349d",
+            "0x2fa5e5f18f6027a6501bec864564472a616b2e274a41211a444cbe3a99f3cc61",
+            "0x0e884376d0d8fd21ecb780389e941f66e45e7acce3e228ab3e2156a614fcd747",
+            "0x1b7201da72494f1e28717ad1a52eb469f95892f957713533de6175e5da190af2",
+            "0x1f8d8822725e36385200c0b201249819a6e6e1e4650808b5bebc6bface7d7636",
+            "0x2c5d82f66c914bafb9701589ba8cfcfb6162b0a12acf88a8d0879a0471b5f85a",
+            "0x14c54148a0940bb820957f5adf3fa1134ef5c4aaa113f4646458f270e0bfbfd0",
+            "0x190d33b12f986f961e10c0ee44d8b9af11be25588cad89d416118e4bf4ebe80c",
+            "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
+            "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
+            "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
+            "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
+            "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
+        ]
+        .map(|e| str_to_fr(e, 16).unwrap())
+        .to_vec();
 
-        let mut expected_identity_path_index: Vec<u8> =
-            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
-
-        // We add the remaining elements for the case TEST_TREE_HEIGHT = 20
-        if TEST_TREE_HEIGHT == 19 || TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![
-                str_to_fr(
-                    "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x2a7c7c9b6ce5880b9f6f228d72bf6a575a526f29c66ecceef8b753d38bba7323",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x2e8186e558698ec1c67af9c14d463ffc470043c9c2988b954d75dd643f36b992",
-                    16,
-                )
-                .unwrap(),
-                str_to_fr(
-                    "0x0f57c5571e9a4eab49e2c8cf050dae948aef6ead647392273546249d1c1ff10f",
-                    16,
-                )
-                .unwrap(),
-            ]);
-            expected_identity_path_index.append(&mut vec![0, 0, 0, 0]);
-        }
-
-        if TEST_TREE_HEIGHT == 20 {
-            expected_path_elements.append(&mut vec![str_to_fr(
-                "0x1830ee67b5fb554ad5f63d4388800e1cfe78e310697d46e43c9ce36134f72cca",
-                16,
-            )
-            .unwrap()]);
-            expected_identity_path_index.append(&mut vec![0]);
-        }
+        let expected_identity_path_index: Vec<u8> =
+            vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
 
         assert_eq!(path_elements, expected_path_elements);
         assert_eq!(identity_path_index, expected_identity_path_index);
 
+        // check subtree root computation for leaf 0 for all corresponding node until the root
+        let l_idx = 0;
+        for n in (1..=TEST_TREE_HEIGHT).rev() {
+            let idx_l = l_idx * (1 << (TEST_TREE_HEIGHT - n));
+            let idx_r = (l_idx + 1) * (1 << (TEST_TREE_HEIGHT - n));
+            let idx_sr = idx_l;
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n, idx_l, &mut buffer).unwrap();
+            let (prev_l, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n, idx_r, &mut buffer).unwrap();
+            let (prev_r, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let mut buffer = Cursor::new(Vec::<u8>::new());
+            rln.get_subtree_root(n - 1, idx_sr, &mut buffer).unwrap();
+            let (subroot, _) = bytes_le_to_fr(&buffer.into_inner());
+
+            let res = utils_poseidon_hash(&[prev_l, prev_r]);
+            assert_eq!(res, subroot);
+        }
+
         // We double check that the proof computed from public API is correct
-        let root_from_proof =
-            compute_tree_root(&id_commitment, &path_elements, &identity_path_index, false);
+        let root_from_proof = compute_tree_root(
+            &identity_secret_hash,
+            &user_message_limit.into(),
+            &path_elements,
+            &identity_path_index,
+        );
 
         assert_eq!(root, root_from_proof);
     }

semaphore/Cargo.toml

@@ -1,50 +0,0 @@
-[package]
-name = "semaphore-wrapper"
-version = "0.1.0"
-edition = "2021"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[features]
-default = []
-dylib = [ "wasmer/dylib", "wasmer-engine-dylib", "wasmer-compiler-cranelift" ]
-
-[dependencies]
-ark-bn254 = { version = "0.3.0" }
-ark-circom = { git = "https://github.com/gakonst/ark-circom", features=["circom-2"], rev = "35ce5a9" }
-ark-ec = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-ark-relations = { version = "0.3.0", default-features = false }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-color-eyre = "0.6.1"
-once_cell = "1.8"
-rand = "0.8.4"
-semaphore = { git = "https://github.com/worldcoin/semaphore-rs", rev = "ee658c2"}
-ethers-core = { version = "2.0.8", default-features = false }
-ruint = { version = "1.2.0", features = [ "serde", "num-bigint", "ark-ff" ] }
-serde = "1.0"
-thiserror = "1.0.0"
-wasmer = { version = "2.0" }
-
-[dev-dependencies]
-rand_chacha = "0.3.1"
-serde_json = "1.0.79"
-
-[build-dependencies]
-color-eyre = "0.6.1"
-wasmer = { version = "2.0" }
-wasmer-engine-dylib = { version = "2.2.1", optional = true }
-wasmer-compiler-cranelift = { version = "3.1.1", optional = true }
-
-[profile.release]
-codegen-units = 1
-lto = true
-panic = "abort"
-opt-level = 3
-
-# Compilation profile for any non-workspace member.
-# Dependencies are optimized, even in a dev build. This improves dev performance
-# while having neglible impact on incremental build times.
-[profile.dev.package."*"]
-opt-level = 3

semaphore/Makefile.toml

@@ -1,7 +0,0 @@
-[tasks.build]
-command = "cargo"
-args = ["build", "--release"]
-
-[tasks.test]
-command = "cargo"
-args = ["test", "--release"]

semaphore/README.md

@@ -1,18 +0,0 @@
-# Semaphore example package
-
-This is basically a wrapper around/copy of
-https://github.com/worldcoin/semaphore-rs to illustrate how e.g. RLN package
-can be structured like.
-
-Goal is also to provide a basic FFI around protocol.rs, which is currently not
-in scope for that project.
-
-See that project for more information.
-
-## Build and Test
-
-To build and test, run the following commands within the module folder
-```bash
-cargo make build
-cargo make test
-```

semaphore/build.rs

@@ -1,111 +0,0 @@
-// Adapted from semaphore-rs/build.rs
-use color_eyre::eyre::{eyre, Result};
-use std::{
-    path::{Component, Path, PathBuf},
-    process::Command,
-};
-
-const ZKEY_FILE: &str = "./vendor/semaphore/build/snark/semaphore_final.zkey";
-const WASM_FILE: &str = "./vendor/semaphore/build/snark/semaphore.wasm";
-
-// See <https://internals.rust-lang.org/t/path-to-lexical-absolute/14940>
-fn absolute(path: &str) -> Result<PathBuf> {
-    let path = Path::new(path);
-    let mut absolute = if path.is_absolute() {
-        PathBuf::new()
-    } else {
-        std::env::current_dir()?
-    };
-    for component in path.components() {
-        match component {
-            Component::CurDir => {}
-            Component::ParentDir => {
-                absolute.pop();
-            }
-            component => absolute.push(component.as_os_str()),
-        }
-    }
-    Ok(absolute)
-}
-
-fn build_circuit() -> Result<()> {
-    println!("cargo:rerun-if-changed=./vendor/semaphore");
-    let run = |cmd: &[&str]| -> Result<()> {
-        // TODO: Use ExitCode::exit_ok() when stable.
-        Command::new(cmd[0])
-            .args(cmd[1..].iter())
-            .current_dir("./vendor/semaphore")
-            .status()?
-            .success()
-            .then_some(())
-            .ok_or(eyre!("procees returned failure"))?;
-        Ok(())
-    };
-
-    // Compute absolute paths
-    let zkey_file = absolute(ZKEY_FILE)?;
-    let wasm_file = absolute(WASM_FILE)?;
-
-    // Build circuits if not exists
-    // TODO: This does not rebuild if the semaphore submodule is changed.
-    // NOTE: This requires npm / nodejs to be installed.
-    if !(zkey_file.exists() && wasm_file.exists()) {
-        run(&["npm", "install"])?;
-        run(&["npm", "exec", "ts-node", "./scripts/compile-circuits.ts"])?;
-    }
-    assert!(zkey_file.exists());
-    assert!(wasm_file.exists());
-
-    // Export generated paths
-    println!("cargo:rustc-env=BUILD_RS_ZKEY_FILE={}", zkey_file.display());
-    println!("cargo:rustc-env=BUILD_RS_WASM_FILE={}", wasm_file.display());
-
-    Ok(())
-}
-
-#[cfg(feature = "dylib")]
-fn build_dylib() -> Result<()> {
-    use enumset::enum_set;
-    use std::{env, str::FromStr};
-    use wasmer::{Module, Store, Target, Triple};
-    use wasmer_compiler_cranelift::Cranelift;
-    use wasmer_engine_dylib::Dylib;
-
-    let wasm_file = absolute(WASM_FILE)?;
-    assert!(wasm_file.exists());
-
-    let out_dir = env::var("OUT_DIR")?;
-    let out_dir = Path::new(&out_dir).to_path_buf();
-    let dylib_file = out_dir.join("semaphore.dylib");
-    println!(
-        "cargo:rustc-env=CIRCUIT_WASM_DYLIB={}",
-        dylib_file.display()
-    );
-
-    if dylib_file.exists() {
-        return Ok(());
-    }
-
-    // Create a WASM engine for the target that can compile
-    let triple = Triple::from_str(&env::var("TARGET")?).map_err(|e| eyre!(e))?;
-    let cpu_features = enum_set!();
-    let target = Target::new(triple, cpu_features);
-    let compiler_config = Cranelift::default();
-    let engine = Dylib::new(compiler_config).target(target).engine();
-
-    // Compile the WASM module
-    let store = Store::new(&engine);
-    let module = Module::from_file(&store, &wasm_file)?;
-    module.serialize_to_file(&dylib_file)?;
-    assert!(dylib_file.exists());
-    println!("cargo:warning=Circuit dylib is in {}", dylib_file.display());
-
-    Ok(())
-}
-
-fn main() -> Result<()> {
-    build_circuit()?;
-    #[cfg(feature = "dylib")]
-    build_dylib()?;
-    Ok(())
-}

semaphore/src/circuit.rs

@@ -1,79 +0,0 @@
-// Adapted from semaphore-rs/src/circuit.rs
-use ark_bn254::{Bn254, Fr};
-use ark_circom::{read_zkey, WitnessCalculator};
-use ark_groth16::ProvingKey;
-use ark_relations::r1cs::ConstraintMatrices;
-use core::include_bytes;
-use once_cell::sync::{Lazy, OnceCell};
-use std::{io::Cursor, sync::Mutex};
-use wasmer::{Module, Store};
-
-#[cfg(feature = "dylib")]
-use std::{env, path::Path};
-#[cfg(feature = "dylib")]
-use wasmer::Dylib;
-
-const ZKEY_BYTES: &[u8] = include_bytes!(env!("BUILD_RS_ZKEY_FILE"));
-
-#[cfg(not(feature = "dylib"))]
-const WASM: &[u8] = include_bytes!(env!("BUILD_RS_WASM_FILE"));
-
-static ZKEY: Lazy<(ProvingKey<Bn254>, ConstraintMatrices<Fr>)> = Lazy::new(|| {
-    let mut reader = Cursor::new(ZKEY_BYTES);
-    read_zkey(&mut reader).expect("zkey should be valid")
-});
-
-static WITNESS_CALCULATOR: OnceCell<Mutex<WitnessCalculator>> = OnceCell::new();
-
-/// Initialize the library.
-#[cfg(feature = "dylib")]
-pub fn initialize(dylib_path: &Path) {
-    WITNESS_CALCULATOR
-        .set(from_dylib(dylib_path))
-        .expect("Failed to initialize witness calculator");
-
-    // Force init of ZKEY
-    Lazy::force(&ZKEY);
-}
-
-#[cfg(feature = "dylib")]
-fn from_dylib(path: &Path) -> Mutex<WitnessCalculator> {
-    let store = Store::new(&Dylib::headless().engine());
-    // The module must be exported using [`Module::serialize`].
-    let module = unsafe {
-        Module::deserialize_from_file(&store, path).expect("Failed to load wasm dylib module")
-    };
-    let result =
-        WitnessCalculator::from_module(module).expect("Failed to create witness calculator");
-    Mutex::new(result)
-}
-
-#[must_use]
-pub fn zkey() -> &'static (ProvingKey<Bn254>, ConstraintMatrices<Fr>) {
-    &ZKEY
-}
-
-#[cfg(feature = "dylib")]
-#[must_use]
-pub fn witness_calculator() -> &'static Mutex<WitnessCalculator> {
-    WITNESS_CALCULATOR.get_or_init(|| {
-        let path = env::var("CIRCUIT_WASM_DYLIB").expect(
-            "Semaphore-rs is not initialized. The library needs to be initialized before use when \
-             build with the `cdylib` feature. You can initialize by calling `initialize` or \
-             seting the `CIRCUIT_WASM_DYLIB` environment variable.",
-        );
-        from_dylib(Path::new(&path))
-    })
-}
-
-#[cfg(not(feature = "dylib"))]
-#[must_use]
-pub fn witness_calculator() -> &'static Mutex<WitnessCalculator> {
-    WITNESS_CALCULATOR.get_or_init(|| {
-        let store = Store::default();
-        let module = Module::from_binary(&store, WASM).expect("wasm should be valid");
-        let result =
-            WitnessCalculator::from_module(module).expect("Failed to create witness calculator");
-        Mutex::new(result)
-    })
-}

semaphore/src/lib.rs

@@ -1,7 +0,0 @@
-#![allow(clippy::multiple_crate_versions)]
-
-pub mod circuit;
-pub mod protocol;
-
-#[cfg(feature = "dylib")]
-pub use circuit::initialize;

semaphore/src/protocol.rs

@@ -1,215 +0,0 @@
-// Adapted from semaphore-rs/src/protocol.rs
-// For illustration purposes only as an example protocol
-
-// Private module
-use crate::circuit::{witness_calculator, zkey};
-
-use ark_bn254::{Bn254, Parameters};
-use ark_circom::CircomReduction;
-use ark_ec::bn::Bn;
-use ark_groth16::{
-    create_proof_with_reduction_and_matrices, prepare_verifying_key, Proof as ArkProof,
-};
-use ark_relations::r1cs::SynthesisError;
-use ark_std::UniformRand;
-use color_eyre::{Report, Result};
-use ethers_core::types::U256;
-use rand::{thread_rng, Rng};
-use semaphore::{
-    identity::Identity,
-    merkle_tree::{self, Branch},
-    poseidon,
-    poseidon_tree::PoseidonHash,
-    Field,
-};
-use serde::{Deserialize, Serialize};
-use std::time::Instant;
-use thiserror::Error;
-
-// Matches the private G1Tup type in ark-circom.
-pub type G1 = (U256, U256);
-
-// Matches the private G2Tup type in ark-circom.
-pub type G2 = ([U256; 2], [U256; 2]);
-
-/// Wrap a proof object so we have serde support
-#[derive(Clone, Copy, Debug, PartialEq, Eq, Serialize, Deserialize)]
-pub struct Proof(G1, G2, G1);
-
-impl From<ArkProof<Bn<Parameters>>> for Proof {
-    fn from(proof: ArkProof<Bn<Parameters>>) -> Self {
-        let proof = ark_circom::ethereum::Proof::from(proof);
-        let (a, b, c) = proof.as_tuple();
-        Self(a, b, c)
-    }
-}
-
-impl From<Proof> for ArkProof<Bn<Parameters>> {
-    fn from(proof: Proof) -> Self {
-        let eth_proof = ark_circom::ethereum::Proof {
-            a: ark_circom::ethereum::G1 {
-                x: proof.0 .0,
-                y: proof.0 .1,
-            },
-            #[rustfmt::skip] // Rustfmt inserts some confusing spaces
-            b: ark_circom::ethereum::G2 {
-                // The order of coefficients is flipped.
-                x: [proof.1.0[1], proof.1.0[0]],
-                y: [proof.1.1[1], proof.1.1[0]],
-            },
-            c: ark_circom::ethereum::G1 {
-                x: proof.2 .0,
-                y: proof.2 .1,
-            },
-        };
-        eth_proof.into()
-    }
-}
-
-/// Helper to merkle proof into a bigint vector
-/// TODO: we should create a From trait for this
-fn merkle_proof_to_vec(proof: &merkle_tree::Proof<PoseidonHash>) -> Vec<Field> {
-    proof
-        .0
-        .iter()
-        .map(|x| match x {
-            Branch::Left(value) | Branch::Right(value) => *value,
-        })
-        .collect()
-}
-
-/// Generates the nullifier hash
-#[must_use]
-pub fn generate_nullifier_hash(identity: &Identity, external_nullifier: Field) -> Field {
-    poseidon::hash2(external_nullifier, identity.nullifier)
-}
-
-#[derive(Error, Debug)]
-pub enum ProofError {
-    #[error("Error reading circuit key: {0}")]
-    CircuitKeyError(#[from] std::io::Error),
-    #[error("Error producing witness: {0}")]
-    WitnessError(Report),
-    #[error("Error producing proof: {0}")]
-    SynthesisError(#[from] SynthesisError),
-    #[error("Error converting public input: {0}")]
-    ToFieldError(#[from] ruint::ToFieldError),
-}
-
-/// Generates a semaphore proof
-///
-/// # Errors
-///
-/// Returns a [`ProofError`] if proving fails.
-pub fn generate_proof(
-    identity: &Identity,
-    merkle_proof: &merkle_tree::Proof<PoseidonHash>,
-    external_nullifier_hash: Field,
-    signal_hash: Field,
-) -> Result<Proof, ProofError> {
-    generate_proof_rng(
-        identity,
-        merkle_proof,
-        external_nullifier_hash,
-        signal_hash,
-        &mut thread_rng(),
-    )
-}
-
-/// Generates a semaphore proof from entropy
-///
-/// # Errors
-///
-/// Returns a [`ProofError`] if proving fails.
-pub fn generate_proof_rng(
-    identity: &Identity,
-    merkle_proof: &merkle_tree::Proof<PoseidonHash>,
-    external_nullifier_hash: Field,
-    signal_hash: Field,
-    rng: &mut impl Rng,
-) -> Result<Proof, ProofError> {
-    generate_proof_rs(
-        identity,
-        merkle_proof,
-        external_nullifier_hash,
-        signal_hash,
-        ark_bn254::Fr::rand(rng),
-        ark_bn254::Fr::rand(rng),
-    )
-}
-
-fn generate_proof_rs(
-    identity: &Identity,
-    merkle_proof: &merkle_tree::Proof<PoseidonHash>,
-    external_nullifier_hash: Field,
-    signal_hash: Field,
-    r: ark_bn254::Fr,
-    s: ark_bn254::Fr,
-) -> Result<Proof, ProofError> {
-    let inputs = [
-        ("identityNullifier", vec![identity.nullifier]),
-        ("identityTrapdoor", vec![identity.trapdoor]),
-        ("treePathIndices", merkle_proof.path_index()),
-        ("treeSiblings", merkle_proof_to_vec(merkle_proof)),
-        ("externalNullifier", vec![external_nullifier_hash]),
-        ("signalHash", vec![signal_hash]),
-    ];
-    let inputs = inputs.into_iter().map(|(name, values)| {
-        (
-            name.to_string(),
-            values.iter().copied().map(Into::into).collect::<Vec<_>>(),
-        )
-    });
-
-    let now = Instant::now();
-
-    let full_assignment = witness_calculator()
-        .lock()
-        .expect("witness_calculator mutex should not get poisoned")
-        .calculate_witness_element::<Bn254, _>(inputs, false)
-        .map_err(ProofError::WitnessError)?;
-
-    println!("witness generation took: {:.2?}", now.elapsed());
-
-    let now = Instant::now();
-    let zkey = zkey();
-    let ark_proof = create_proof_with_reduction_and_matrices::<_, CircomReduction>(
-        &zkey.0,
-        r,
-        s,
-        &zkey.1,
-        zkey.1.num_instance_variables,
-        zkey.1.num_constraints,
-        full_assignment.as_slice(),
-    )?;
-    let proof = ark_proof.into();
-    println!("proof generation took: {:.2?}", now.elapsed());
-
-    Ok(proof)
-}
-
-/// Verifies a given semaphore proof
-///
-/// # Errors
-///
-/// Returns a [`ProofError`] if verifying fails. Verification failure does not
-/// necessarily mean the proof is incorrect.
-pub fn verify_proof(
-    root: Field,
-    nullifier_hash: Field,
-    signal_hash: Field,
-    external_nullifier_hash: Field,
-    proof: &Proof,
-) -> Result<bool, ProofError> {
-    let zkey = zkey();
-    let pvk = prepare_verifying_key(&zkey.0.vk);
-
-    let public_inputs = [root, nullifier_hash, signal_hash, external_nullifier_hash]
-        .iter()
-        .map(ark_bn254::Fr::try_from)
-        .collect::<Result<Vec<_>, _>>()?;
-
-    let ark_proof = (*proof).into();
-    let result = ark_groth16::verify_proof(&pvk, &ark_proof, &public_inputs[..])?;
-    Ok(result)
-}

semaphore/tests/protocol.rs

@@ -1,115 +0,0 @@
-#[cfg(test)]
-mod tests {
-    use ark_bn254::Parameters;
-    use ark_ec::bn::Bn;
-    use ark_groth16::Proof as ArkProof;
-    use rand::{Rng, SeedableRng as _};
-    use rand_chacha::ChaChaRng;
-    use semaphore::{hash_to_field, identity::Identity, poseidon_tree::PoseidonTree, Field};
-    use semaphore_wrapper::protocol::{
-        generate_nullifier_hash, generate_proof, generate_proof_rng, verify_proof, Proof,
-    };
-    use serde_json::json;
-
-    #[test]
-    fn test_semaphore() {
-        // generate identity
-        let id = Identity::from_seed(b"secret");
-
-        // generate merkle tree
-        let leaf = Field::from(0);
-        let mut tree = PoseidonTree::new(21, leaf);
-        tree.set(0, id.commitment());
-
-        let merkle_proof = tree.proof(0).expect("proof should exist");
-        let root = tree.root().into();
-
-        // change signal and external_nullifier here
-        let signal_hash = hash_to_field(b"xxx");
-        let external_nullifier_hash = hash_to_field(b"appId");
-
-        let nullifier_hash = generate_nullifier_hash(&id, external_nullifier_hash);
-
-        let proof =
-            generate_proof(&id, &merkle_proof, external_nullifier_hash, signal_hash).unwrap();
-
-        let success = verify_proof(
-            root,
-            nullifier_hash,
-            signal_hash,
-            external_nullifier_hash,
-            &proof,
-        )
-        .unwrap();
-
-        assert!(success);
-    }
-
-    fn arb_proof(seed: u64) -> Proof {
-        // Deterministic randomness for testing
-        let mut rng = ChaChaRng::seed_from_u64(seed);
-
-        // generate identity
-        let seed: [u8; 16] = rng.gen();
-        let id = Identity::from_seed(&seed);
-
-        // generate merkle tree
-        let leaf = Field::from(0);
-        let mut tree = PoseidonTree::new(21, leaf);
-        tree.set(0, id.commitment());
-
-        let merkle_proof = tree.proof(0).expect("proof should exist");
-
-        let external_nullifier: [u8; 16] = rng.gen();
-        let external_nullifier_hash = hash_to_field(&external_nullifier);
-
-        let signal: [u8; 16] = rng.gen();
-        let signal_hash = hash_to_field(&signal);
-
-        generate_proof_rng(
-            &id,
-            &merkle_proof,
-            external_nullifier_hash,
-            signal_hash,
-            &mut rng,
-        )
-        .unwrap()
-    }
-
-    #[test]
-    fn test_proof_cast_roundtrip() {
-        let proof = arb_proof(123);
-        let ark_proof: ArkProof<Bn<Parameters>> = proof.into();
-        let result: Proof = ark_proof.into();
-        assert_eq!(proof, result);
-    }
-
-    #[test]
-    fn test_proof_serialize() {
-        let proof = arb_proof(456);
-        let json = serde_json::to_value(&proof).unwrap();
-        assert_eq!(
-            json,
-            json!([
-                [
-                    "0x249ae469686987ee9368da60dd177a8c42891c02f5760e955e590c79d55cfab2",
-                    "0xf22e25870f49388459d388afb24dcf6ec11bb2d4def1e2ec26d6e42f373aad8"
-                ],
-                [
-                    [
-                        "0x17bd25dbd7436c30ea5b8a3a47aadf11ed646c4b25cc14a84ff8cbe0252ff1f8",
-                        "0x1c140668c56688367416534d57b4a14e5a825efdd5e121a6a2099f6dc4cd277b"
-                    ],
-                    [
-                        "0x26a8524759d969ea0682a092cf7a551697d81962d6c998f543f81e52d83e05e1",
-                        "0x273eb3f796fd1807b9df9c6d769d983e3dabdc61677b75d48bb7691303b2c8dd"
-                    ]
-                ],
-                [
-                    "0x62715c53a0eb4c46dbb5f73f1fd7449b9c63d37c1ece65debc39b472065a90f",
-                    "0x114f7becc66f1cd7a8b01c89db8233622372fc0b6fc037c4313bca41e2377fd9"
-                ]
-            ])
-        );
-    }
-}

utils/Cargo.toml

@@ -1,9 +1,12 @@
 [package]
 name = "zerokit_utils"
-version = "0.1.0"
+version = "0.5.0"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Various utilities for Zerokit"
+documentation = "https://github.com/vacp2p/zerokit"
+homepage = "https://vac.dev"
+repository = "https://github.com/vacp2p/zerokit"
 
 [lib]
 bench = false
@@ -12,9 +15,11 @@ bench = false
 ark-ff = { version = "=0.4.1", default-features = false, features = ["asm"] }
 num-bigint = { version = "=0.4.3", default-features = false, features = ["rand"] }
 color-eyre = "=0.6.2"
-pmtree = { package = "vacp2p_pmtree", version = "=1.0.0", optional = true}
+pmtree = { package = "vacp2p_pmtree", version = "=2.0.2", optional = true}
 sled = "=0.34.7"
 serde = "=1.0.163"
+lazy_static = "1.4.0"
+hex = "0.4"
 
 [dev-dependencies]
 ark-bn254 = "=0.4.0"

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

@@ -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
@@ -211,6 +252,7 @@ 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(())
     }

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

@@ -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,
@@ -78,6 +82,7 @@ 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 +103,7 @@ where
     }
 
     // Returns the total number of leaves set
-    fn leaves_set(&mut self) -> usize {
+    fn leaves_set(&self) -> usize {
         self.next_index
     }
 
@@ -108,6 +113,22 @@ 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 +137,7 @@ 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 +149,16 @@ 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 +168,43 @@ 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
@@ -183,6 +218,7 @@ 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(())
     }
@@ -266,6 +302,7 @@ where
             i >>= 1;
             depth -= 1;
             self.nodes.insert((depth, i), h);
+            self.cached_leaves_indices[index] = 1;
             if depth == 0 {
                 break;
             }

utils/src/pm_tree/sled_adapter.rs

@@ -2,29 +2,51 @@ use pmtree::*;
 
 use sled::Db as Sled;
 use std::collections::HashMap;
+use std::thread;
+use std::time::Duration;
 
 pub struct SledDB(Sled);
 
+impl SledDB {
+    fn new_with_tries(config: <SledDB as Database>::Config, tries: u32) -> PmtreeResult<Self> {
+        // If we've tried more than 10 times, we give up and return an error.
+        if tries >= 10 {
+            return Err(PmtreeErrorKind::DatabaseError(
+                DatabaseErrorKind::CustomError(format!(
+                    "Cannot create database: exceeded maximum retry attempts. {config:#?}"
+                )),
+            ));
+        }
+        match config.open() {
+            Ok(db) => Ok(SledDB(db)),
+            Err(e) if e.to_string().contains("WouldBlock") => {
+                // try till the fd is freed
+                // sleep for 10^tries milliseconds, then recursively try again
+                thread::sleep(Duration::from_millis(10u64.pow(tries)));
+                Self::new_with_tries(config, tries + 1)
+            }
+            Err(e) => {
+                // On any other error, we return immediately.
+                Err(PmtreeErrorKind::DatabaseError(
+                    DatabaseErrorKind::CustomError(format!(
+                        "Cannot create database: {e} {config:#?}"
+                    )),
+                ))
+            }
+        }
+    }
+}
+
 impl Database for SledDB {
     type Config = sled::Config;
 
     fn new(config: Self::Config) -> PmtreeResult<Self> {
-        let db: Sled = match config.open() {
-            Ok(db) => db,
-            Err(e) => {
-                return Err(PmtreeErrorKind::DatabaseError(
-                    DatabaseErrorKind::CustomError(format!(
-                        "Cannot create database: {e} {config:#?}",
-                    )),
-                ))
-            }
-        };
-
-        Ok(SledDB(db))
+        let db = Self::new_with_tries(config, 0)?;
+        Ok(db)
     }
 
     fn load(config: Self::Config) -> PmtreeResult<Self> {
-        let db: Sled = match sled::open(&config.path) {
+        let db = match config.open() {
             Ok(db) => db,
             Err(e) => {
                 return Err(PmtreeErrorKind::DatabaseError(

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!();
         }
     }
 }