chore(ci): add arkzkey feature to nightly assets (#244)

* Add Submodule

* Add arkzkey

* make arkzkey support as feature

* update submodule url

* add abstract around feature

* new bench file

* 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
@@ -130,8 +123,10 @@ jobs:
     steps:
       - name: Checkout sources
         uses: actions/checkout@v3
+        with:
+          submodules: true
       - uses: Swatinem/rust-cache@v2
       - 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

@@ -1,4 +1,3 @@
-[submodule "semaphore/vendor/semaphore"]
-	path = semaphore/vendor/semaphore
-	ignore = dirty
-	url = https://github.com/appliedzkp/semaphore.git
+[submodule "mopro"]
+	path = mopro
+	url = https://github.com/zkmopro/mopro.git

Cargo.toml

@@ -1,13 +1,6 @@
 [workspace]
-members = [
-  "multiplier",
-  "private-settlement",
-  "semaphore",
-  "rln",
-  "rln-cli",
-  "rln-wasm",
-  "utils",
-]
+members = ["rln", "rln-cli", "rln-wasm", "utils"]
+default-members = ["rln", "rln-cli", "utils"]
 resolver = "2"
 
 # Compilation profile for any non-workspace member.
@@ -19,6 +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 = "0.3.0"
-edition = "2018"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]
-
-# WASM operations
-# wasmer = { version = "2.0" }
-# fnv = { version = "1.0.3", default-features = false }
-# num = { version = "0.4.0" }
-# num-traits = { version = "0.2.0", default-features = false }
-
-# ZKP Generation
-# ark-ff = { version = "0.3.0", default-features = false, features = ["parallel", "asm"] }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-bn254 = { version = "0.3.0" }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-# ark-poly = { version = "^0.3.0", default-features = false, features = ["parallel"] }
-ark-serialize = { version = "0.3.0", default-features = false }
-
-ark-circom = { git = "https://github.com/gakonst/ark-circom", features = ["circom-2"], rev = "35ce5a9" }
-
-# error handling
-color-eyre = "0.6.1"
-
-# decoding of data
-# hex = "0.4.3"
-# byteorder = "1.4.3"

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 = "0.3.0"
-edition = "2021"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[dependencies]

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/src/main.rs

@@ -37,7 +37,11 @@ fn main() -> Result<()> {
             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)?;

rln-wasm/Cargo.toml

@@ -3,6 +3,9 @@ name = "rln-wasm"
 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/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rln"
-version = "0.4.1"
+version = "0.4.3"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
@@ -19,13 +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 = { path = "../mopro/ark-zkey", optional = true, default-features = false }
 
 # WASM
 wasmer = { version = "=2.3.0", default-features = false }
@@ -36,13 +43,15 @@ 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 = "=0.4.1", path = "../utils/", default-features = false }
+utils = { package = "zerokit_utils", version = "=0.4.3", path = "../utils/", default-features = false }
 
 
 # serialization
@@ -57,9 +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"]
@@ -67,3 +83,7 @@ pmtree-ft = ["utils/pmtree-ft"]
 [[bench]]
 name = "pmtree_benchmark"
 harness = false
+
+[[bench]]
+name = "circuit_loading_benchmark"
+harness = false

rln/benches/circuit_loading_benchmark.rs

@@ -0,0 +1,15 @@
+use criterion::{criterion_group, criterion_main, Criterion};
+use rln::circuit::TEST_RESOURCES_FOLDER;
+
+// 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(TEST_RESOURCES_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();

rln/resources/tree_height_32/verification_key.json

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

rln/src/circuit.rs

@@ -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! {
@@ -25,16 +23,23 @@ cfg_if! {
     }
 }
 
+cfg_if! {
+    if #[cfg(feature = "arkzkey")] {
+        use ark_zkey::read_arkzkey_from_bytes;
+        const ARKZKEY_FILENAME: &str = "rln_final.arkzkey";
+
+    } else {
+        use std::io::Cursor;
+        use ark_circom::read_zkey;
+    }
+}
+
 const ZKEY_FILENAME: &str = "rln_final.zkey";
 const VK_FILENAME: &str = "verification_key.json";
 const WASM_FILENAME: &str = "rln.wasm";
 
-// These parameters are used for tests
-// Note that the circuit and keys in TEST_RESOURCES_FOLDER are compiled for Merkle trees of height 20 & 32
-// Changing these parameters to other values than these defaults will cause zkSNARK proof verification to fail
-pub const TEST_PARAMETERS_INDEX: usize = 0;
-pub const TEST_TREE_HEIGHT: usize = [20, 32][TEST_PARAMETERS_INDEX];
-pub const TEST_RESOURCES_FOLDER: &str = ["tree_height_20", "tree_height_32"][TEST_PARAMETERS_INDEX];
+pub const TEST_TREE_HEIGHT: usize = 20;
+pub const TEST_RESOURCES_FOLDER: &str = "tree_height_20";
 
 #[cfg(not(target_arch = "wasm32"))]
 static RESOURCES_DIR: Dir<'_> = include_dir!("$CARGO_MANIFEST_DIR/resources");
@@ -53,8 +58,15 @@ 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!"))
@@ -66,10 +78,21 @@ pub fn zkey_from_raw(zkey_data: &Vec<u8>) -> Result<(ProvingKey<Curve>, Constrai
 pub fn zkey_from_folder(
     resources_folder: &str,
 ) -> Result<(ProvingKey<Curve>, ConstraintMatrices<Fr>)> {
+    #[cfg(feature = "arkzkey")]
+    let zkey = RESOURCES_DIR.get_file(Path::new(resources_folder).join(ARKZKEY_FILENAME));
+    #[cfg(not(feature = "arkzkey"))]
     let zkey = RESOURCES_DIR.get_file(Path::new(resources_folder).join(ZKEY_FILENAME));
+
     if let Some(zkey) = zkey {
-        let mut c = Cursor::new(zkey.contents());
-        let proving_key_and_matrices = read_zkey(&mut c)?;
+        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!"))
@@ -77,7 +100,7 @@ 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() {
@@ -145,7 +168,7 @@ 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

rln/src/pm_tree_adapter.rs

@@ -246,7 +246,8 @@ impl ZerokitMerkleTree for PmTree {
         let data = self.tree.db.get(METADATA_KEY)?;
 
         if data.is_none() {
-            return Err(Report::msg("metadata does not exist"));
+            // send empty Metadata
+            return Ok(Vec::new());
         }
         Ok(data.unwrap())
     }

rln/src/public.rs

@@ -58,7 +58,7 @@ impl RLN<'_> {
     ///
     /// Input parameters are
     /// - `tree_height`: the height of the internal Merkle tree
-    /// - `input_data`: a reader for the string path of the resource folder containing the ZK circuit (`rln.wasm`), the proving key (`rln_final.zkey`) and the verification key (`verification_key.json`).
+    /// - `input_data`: a reader for the string path of the resource folder containing the ZK circuit (`rln.wasm`), the proving key (`rln_final.zkey`) or (`rln_final.arkzkey`) and the verification key (`verification_key.json`).
     ///
     /// Example:
     /// ```
@@ -83,8 +83,8 @@ impl RLN<'_> {
         let tree_config = rln_config["tree_config"].to_string();
 
         let witness_calculator = circom_from_folder(resources_folder)?;
-
         let proving_key = zkey_from_folder(resources_folder)?;
+
         let verification_key = vk_from_folder(resources_folder)?;
 
         let tree_config: <PoseidonTree as ZerokitMerkleTree>::Config = if tree_config.is_empty() {
@@ -115,7 +115,7 @@ impl RLN<'_> {
     /// Input parameters are
     /// - `tree_height`: the height of the internal Merkle tree
     /// - `circom_vec`: a byte vector containing the ZK circuit (`rln.wasm`) as binary file
-    /// - `zkey_vec`: a byte vector containing to the proving key (`rln_final.zkey`) as binary file
+    /// - `zkey_vec`: a byte vector containing to the proving key (`rln_final.zkey`)  or (`rln_final.arkzkey`) as binary file
     /// - `vk_vec`: a byte vector containing to the verification key (`verification_key.json`) as binary file
     /// - `tree_config`: a reader for a string containing a json with the merkle tree configuration
     ///
@@ -684,7 +684,7 @@ impl RLN<'_> {
     /// Output values are:
     /// - `output_data`: a writer receiving the serialization of the zkSNARK proof and the circuit evaluations outputs, i.e. `[ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]`
     ///
-    /// Example    
+    /// Example
     /// ```
     /// use rln::protocol::*:
     /// use rln::utils::*;
@@ -829,7 +829,7 @@ impl RLN<'_> {
     /// Note that contrary to [`verify_rln_proof`](crate::public::RLN::verify_rln_proof), this function does not check if the internal Merkle tree root corresponds to the root provided as input, but rather checks if the root provided as input in `input_data` corresponds to one of the roots serialized in `roots_data`.
     ///
     /// If `roots_data` contains no root (is empty), root validation is skipped and the proof will be correctly verified only if the other proof values results valid (i.e., zk-proof, signal, x-coordinate, RLN identifier)
-    ///   
+    ///
     /// Example
     /// ```
     /// // proof_data is computed as in the example code snippet provided for rln::public::RLN::generate_rln_proof

rln/src/public_api_tests.rs

@@ -977,7 +977,7 @@ fn test_get_leaf() {
 }
 
 #[test]
-fn test_metadata() {
+fn test_valid_metadata() {
     let tree_height = TEST_TREE_HEIGHT;
 
     let input_buffer =
@@ -993,3 +993,18 @@ fn test_metadata() {
 
     assert_eq!(arbitrary_metadata, received_metadata);
 }
+
+#[test]
+fn test_empty_metadata() {
+    let tree_height = TEST_TREE_HEIGHT;
+
+    let input_buffer =
+        Cursor::new(json!({ "resources_folder": TEST_RESOURCES_FOLDER }).to_string());
+    let rln = RLN::new(tree_height, 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

@@ -8,7 +8,7 @@ use num_traits::Num;
 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 +28,10 @@ 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())
     }
 }
 

rln/tests/ffi.rs

@@ -341,7 +341,6 @@ mod test {
     fn test_merkle_proof_ffi() {
         let tree_height = TEST_TREE_HEIGHT;
         let leaf_index = 3;
-        let user_message_limit = 1;
 
         // We create a RLN instance
         let mut rln_pointer = MaybeUninit::<*mut RLN>::uninit();
@@ -373,7 +372,7 @@ mod test {
 
         use ark_ff::BigInt;
 
-        if TEST_TREE_HEIGHT == 20 || TEST_TREE_HEIGHT == 32 {
+        if TEST_TREE_HEIGHT == 20 {
             assert_eq!(
                 root,
                 BigInt([
@@ -619,7 +618,9 @@ mod test {
         circom_file
             .read_exact(&mut circom_buffer)
             .expect("buffer overflow");
-
+        #[cfg(feature = "arkzkey")]
+        let zkey_path = format!("./resources/tree_height_{TEST_TREE_HEIGHT}/rln_final.arkzkey");
+        #[cfg(not(feature = "arkzkey"))]
         let zkey_path = format!("./resources/tree_height_{TEST_TREE_HEIGHT}/rln_final.zkey");
         let mut zkey_file = File::open(&zkey_path).expect("no file found");
         let metadata = std::fs::metadata(&zkey_path).expect("unable to read metadata");
@@ -671,7 +672,7 @@ mod test {
     fn test_rln_proof_ffi() {
         let tree_height = TEST_TREE_HEIGHT;
         let no_of_leaves = 256;
-        let user_message_limit = Fr::from(65535);
+        let user_message_limit = Fr::from(100);
 
         // We generate a vector of random leaves
         let mut leaves: Vec<Fr> = Vec::new();
@@ -704,7 +705,6 @@ mod test {
         let result_data = <&[u8]>::from(&output_buffer).to_vec();
         let (identity_secret_hash, read) = bytes_le_to_fr(&result_data);
         let (id_commitment, _) = bytes_le_to_fr(&result_data[read..].to_vec());
-        let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
 
         let identity_index: usize = no_of_leaves;
 
@@ -717,7 +717,6 @@ mod test {
         let rln_identifier = hash_to_field(b"test-rln-identifier");
         let external_nullifier = utils_poseidon_hash(&[epoch, rln_identifier]);
 
-        let user_message_limit = Fr::from(100);
         let message_id = Fr::from(0);
         let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
 
@@ -727,9 +726,6 @@ mod test {
         let success = set_next_leaf(rln_pointer, input_buffer);
         assert!(success, "set next leaf call failed");
 
-        // 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> | user_message_limit<32> | message_id<32> | external_nullifier<32> | signal_len<8> | signal<var> ]
         let mut serialized: Vec<u8> = Vec::new();
@@ -819,7 +815,6 @@ mod test {
         let message_id = Fr::from(0);
 
         // We set as leaf rate_commitment, its index would be equal to no_of_leaves
-        let rate_commitment = utils_poseidon_hash(&[id_commitment, user_message_limit]);
         let leaf_ser = fr_to_bytes_le(&rate_commitment);
         let input_buffer = &Buffer::from(leaf_ser.as_ref());
         let success = set_next_leaf(rln_pointer, input_buffer);
@@ -1268,7 +1263,7 @@ mod test {
     }
 
     #[test]
-    fn test_metadata() {
+    fn test_valid_metadata() {
         // We create a RLN instance
         let tree_height = TEST_TREE_HEIGHT;
 
@@ -1294,4 +1289,25 @@ mod test {
 
         assert_eq!(result_data, seed_bytes.to_vec());
     }
+
+    #[test]
+    fn test_empty_metadata() {
+        // We create a RLN instance
+        let tree_height = TEST_TREE_HEIGHT;
+
+        let mut rln_pointer = MaybeUninit::<*mut RLN>::uninit();
+        let input_config = json!({ "resources_folder": TEST_RESOURCES_FOLDER }).to_string();
+        let input_buffer = &Buffer::from(input_config.as_bytes());
+        let success = new(tree_height, input_buffer, rln_pointer.as_mut_ptr());
+        assert!(success, "RLN object creation failed");
+        let rln_pointer = unsafe { &mut *rln_pointer.assume_init() };
+
+        let mut output_buffer = MaybeUninit::<Buffer>::uninit();
+        let success = get_metadata(rln_pointer, output_buffer.as_mut_ptr());
+        assert!(success, "get_metadata call failed");
+
+        let output_buffer = unsafe { output_buffer.assume_init() };
+
+        assert_eq!(output_buffer.len, 0);
+    }
 }

rln/tests/protocol.rs

@@ -1,9 +1,9 @@
 #[cfg(test)]
 mod test {
     use ark_ff::BigInt;
+    use rln::circuit::zkey_from_folder;
     use rln::circuit::{
-        circom_from_folder, vk_from_folder, zkey_from_folder, Fr, TEST_RESOURCES_FOLDER,
-        TEST_TREE_HEIGHT,
+        circom_from_folder, vk_from_folder, Fr, TEST_RESOURCES_FOLDER, TEST_TREE_HEIGHT,
     };
     use rln::hashers::{hash_to_field, poseidon_hash};
     use rln::poseidon_tree::PoseidonTree;
@@ -92,7 +92,7 @@ mod test {
         // We check correct computation of the root
         let root = tree.root();
 
-        if TEST_TREE_HEIGHT == 20 || TEST_TREE_HEIGHT == 32 {
+        if TEST_TREE_HEIGHT == 20 {
             assert_eq!(
                 root,
                 BigInt([

rln/tests/public.rs

@@ -46,15 +46,6 @@ mod test {
                     2328960363755461975
                 ]))
             );
-        } else if TEST_TREE_HEIGHT == 32 {
-            assert_eq!(
-                root,
-                str_to_fr(
-                    "0x21947ffd0bce0c385f876e7c97d6a42eec5b1fe935aab2f01c1f8a8cbcc356d2",
-                    16
-                )
-                .unwrap()
-            );
         }
 
         // We check correct computation of merkle proof
@@ -148,7 +139,7 @@ mod test {
             vec![1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
 
         // We add the remaining elements for the case TEST_TREE_HEIGHT = 20
-        if TEST_TREE_HEIGHT == 20 || TEST_TREE_HEIGHT == 32 {
+        if TEST_TREE_HEIGHT == 20 {
             expected_path_elements.append(&mut vec![
                 str_to_fr(
                     "0x22f98aa9ce704152ac17354914ad73ed1167ae6596af510aa5b3649325e06c92",

semaphore/Cargo.toml

@@ -1,50 +0,0 @@
-[package]
-name = "semaphore-wrapper"
-version = "0.3.0"
-edition = "2021"
-license = "MIT OR Apache-2.0"
-
-# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
-
-[features]
-default = []
-dylib = [ "wasmer/dylib", "wasmer-engine-dylib", "wasmer-compiler-cranelift" ]
-
-[dependencies]
-ark-bn254 = { version = "0.3.0" }
-ark-circom = { git = "https://github.com/gakonst/ark-circom", features=["circom-2"], rev = "35ce5a9" }
-ark-ec = { version = "0.3.0", default-features = false, features = ["parallel"] }
-ark-groth16 = { git = "https://github.com/arkworks-rs/groth16", rev = "765817f", features = ["parallel"] }
-ark-relations = { version = "0.3.0", default-features = false }
-ark-std = { version = "0.3.0", default-features = false, features = ["parallel"] }
-color-eyre = "0.6.2"
-once_cell = "1.17.1"
-rand = "0.8.5"
-semaphore = { git = "https://github.com/worldcoin/semaphore-rs", rev = "ee658c2"}
-ethers-core = { version = "2.0.10", default-features = false }
-ruint = { version = "1.10.0", features = [ "serde", "num-bigint", "ark-ff" ] }
-serde = "1.0"
-thiserror = "1.0.39"
-wasmer = { version = "2.3" }
-
-[dev-dependencies]
-rand_chacha = "0.3.1"
-serde_json = "1.0.96"
-
-[build-dependencies]
-color-eyre = "0.6.2"
-wasmer = { version = "2.3" }
-wasmer-engine-dylib = { version = "2.3.0", optional = true }
-wasmer-compiler-cranelift = { version = "3.3.0", 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

@@ -1,6 +1,6 @@
 [package]
 name = "zerokit_utils"
-version = "0.4.1"
+version = "0.4.3"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Various utilities for Zerokit"

utils/benches/merkle_tree_benchmark.rs

@@ -1,5 +1,6 @@
 use criterion::{criterion_group, criterion_main, Criterion};
 use hex_literal::hex;
+use std::{fmt::Display, str::FromStr};
 use tiny_keccak::{Hasher as _, Keccak};
 use zerokit_utils::{
     FullMerkleConfig, FullMerkleTree, Hasher, OptimalMerkleConfig, OptimalMerkleTree,
@@ -9,34 +10,53 @@ 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)
+    }
+}
+
+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()))
+    }
+}
+
+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()))
     }
 }
 
 pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
     let mut tree =
-        OptimalMerkleTree::<Keccak256>::new(2, [0; 32], OptimalMerkleConfig::default()).unwrap();
+        OptimalMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), OptimalMerkleConfig::default())
+            .unwrap();
 
     let leaves = [
         hex!("0000000000000000000000000000000000000000000000000000000000000001"),
         hex!("0000000000000000000000000000000000000000000000000000000000000002"),
         hex!("0000000000000000000000000000000000000000000000000000000000000003"),
         hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-    ];
+    ]
+    .map(|x| TestFr(x));
 
     c.bench_function("OptimalMerkleTree::set", |b| {
         b.iter(|| {
@@ -71,14 +91,15 @@ pub fn optimal_merkle_tree_benchmark(c: &mut Criterion) {
 
 pub fn full_merkle_tree_benchmark(c: &mut Criterion) {
     let mut tree =
-        FullMerkleTree::<Keccak256>::new(2, [0; 32], FullMerkleConfig::default()).unwrap();
+        FullMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), FullMerkleConfig::default()).unwrap();
 
     let leaves = [
         hex!("0000000000000000000000000000000000000000000000000000000000000001"),
         hex!("0000000000000000000000000000000000000000000000000000000000000002"),
         hex!("0000000000000000000000000000000000000000000000000000000000000003"),
         hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-    ];
+    ]
+    .map(|x| TestFr(x));
 
     c.bench_function("FullMerkleTree::set", |b| {
         b.iter(|| {

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;

utils/tests/merkle_tree.rs

@@ -1,6 +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 std::{fmt::Display, str::FromStr};
+
     use hex_literal::hex;
     use tiny_keccak::{Hasher as _, Keccak};
     use zerokit_utils::{
@@ -10,21 +12,38 @@ 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, "{}", String::from_utf8_lossy(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()))
         }
     }
 
@@ -35,20 +54,24 @@ mod test {
             hex!("0000000000000000000000000000000000000000000000000000000000000002"),
             hex!("0000000000000000000000000000000000000000000000000000000000000003"),
             hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-        ];
+        ]
+        .map(|x| TestFr(x));
 
-        let default_tree_root =
-            hex!("b4c11951957c6f8f642c4af61cd6b24640fec6dc7fc607ee8206a99e92410d30");
+        let default_tree_root = TestFr(hex!(
+            "b4c11951957c6f8f642c4af61cd6b24640fec6dc7fc607ee8206a99e92410d30"
+        ));
 
         let roots = [
             hex!("c1ba1812ff680ce84c1d5b4f1087eeb08147a4d510f3496b2849df3a73f5af95"),
             hex!("893760ec5b5bee236f29e85aef64f17139c3c1b7ff24ce64eb6315fca0f2485b"),
             hex!("222ff5e0b5877792c2bc1670e2ccd0c2c97cd7bb1672a57d598db05092d3d72c"),
             hex!("a9bb8c3f1f12e9aa903a50c47f314b57610a3ab32f2d463293f58836def38d36"),
-        ];
+        ]
+        .map(|x| TestFr(x));
 
         let mut tree =
-            FullMerkleTree::<Keccak256>::new(2, [0; 32], FullMerkleConfig::default()).unwrap();
+            FullMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), FullMerkleConfig::default())
+                .unwrap();
         assert_eq!(tree.root(), default_tree_root);
         for i in 0..leaves.len() {
             tree.set(i, leaves[i]).unwrap();
@@ -56,7 +79,7 @@ mod test {
         }
 
         let mut tree =
-            OptimalMerkleTree::<Keccak256>::new(2, [0; 32], OptimalMerkleConfig::default())
+            OptimalMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), OptimalMerkleConfig::default())
                 .unwrap();
         assert_eq!(tree.root(), default_tree_root);
         for i in 0..leaves.len() {
@@ -72,11 +95,13 @@ mod test {
             hex!("0000000000000000000000000000000000000000000000000000000000000002"),
             hex!("0000000000000000000000000000000000000000000000000000000000000003"),
             hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-        ];
+        ]
+        .map(|x| TestFr(x));
 
         // We thest the FullMerkleTree implementation
         let mut tree =
-            FullMerkleTree::<Keccak256>::new(2, [0; 32], FullMerkleConfig::default()).unwrap();
+            FullMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), FullMerkleConfig::default())
+                .unwrap();
         for i in 0..leaves.len() {
             // We set the leaves
             tree.set(i, leaves[i]).unwrap();
@@ -101,7 +126,7 @@ mod test {
 
         // We test the OptimalMerkleTree implementation
         let mut tree =
-            OptimalMerkleTree::<Keccak256>::new(2, [0; 32], OptimalMerkleConfig::default())
+            OptimalMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), OptimalMerkleConfig::default())
                 .unwrap();
         for i in 0..leaves.len() {
             // We set the leaves
@@ -133,10 +158,11 @@ mod test {
             hex!("0000000000000000000000000000000000000000000000000000000000000002"),
             hex!("0000000000000000000000000000000000000000000000000000000000000003"),
             hex!("0000000000000000000000000000000000000000000000000000000000000004"),
-        ];
+        ]
+        .map(|x| TestFr(x));
 
         let mut tree =
-            OptimalMerkleTree::<Keccak256>::new(2, [0; 32], OptimalMerkleConfig::default())
+            OptimalMerkleTree::<Keccak256>::new(2, TestFr([0; 32]), OptimalMerkleConfig::default())
                 .unwrap();
 
         // We set the leaves
@@ -145,7 +171,8 @@ mod test {
         let new_leaves = [
             hex!("0000000000000000000000000000000000000000000000000000000000000005"),
             hex!("0000000000000000000000000000000000000000000000000000000000000006"),
-        ];
+        ]
+        .map(|x| TestFr(x));
 
         let to_delete_indices: [usize; 2] = [0, 1];