chore: Release

.github/workflows/ci.yml

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

.gitmodules

@@ -2,3 +2,7 @@
 	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

@@ -1,5 +1,13 @@
 [workspace]
-members = ["rln", "rln-cli", "rln-wasm", "utils"]
+members = [
+  "multiplier",
+  "private-settlement",
+  "semaphore",
+  "rln",
+  "rln-cli",
+  "rln-wasm",
+  "utils",
+]
 resolver = "2"
 
 # Compilation profile for any non-workspace member.
@@ -11,3 +19,6 @@ 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

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

multiplier/Cargo.toml

@@ -0,0 +1,32 @@
+[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

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

multiplier/README.md

@@ -0,0 +1,21 @@
+# 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

@@ -0,0 +1,77 @@
+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

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

multiplier/src/main.rs

@@ -0,0 +1,49 @@
+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

@@ -0,0 +1,79 @@
+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

@@ -0,0 +1,21 @@
+#[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

@@ -0,0 +1,9 @@
+[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

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

private-settlement/README.md

@@ -0,0 +1,11 @@
+# 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

@@ -0,0 +1 @@
+

private-settlement/tests/private-settlement.rs

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

rln-cli/src/commands.rs

@@ -15,8 +15,6 @@ 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

@@ -34,7 +34,6 @@ 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"] {
@@ -45,13 +44,11 @@ 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::{Config, InnerConfig};
+use crate::config::{InnerConfig, Config};
 
 #[derive(Default)]
 pub(crate) struct State<'a> {

rln-wasm/src/lib.rs

@@ -250,7 +250,11 @@ 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/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "rln"
-version = "0.3.7"
+version = "0.3.1"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "APIs to manage, compute and verify zkSNARK proofs and RLN primitives"
@@ -19,19 +19,13 @@ 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"] }
 
 # WASM
 wasmer = { version = "=2.3.0", default-features = false }
@@ -42,15 +36,13 @@ 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 = "=0.3.3", path = "../utils/", default-features = false }
+utils = { package = "zerokit_utils", version = "=0.3.1", path = "../utils/", default-features = false }
 
 # serialization
 serde_json = "=1.0.96"
@@ -64,13 +56,7 @@ criterion = { version = "=0.4.0", features = ["html_reports"] }
 
 [features]
 default = ["parallel", "wasmer/sys-default", "pmtree-ft"]
-parallel = [
-    "ark-ec/parallel",
-    "ark-ff/parallel",
-    "ark-std/parallel",
-    "ark-groth16/parallel",
-    "utils/parallel",
-]
+parallel = ["ark-ec/parallel", "ark-ff/parallel", "ark-std/parallel", "ark-groth16/parallel", "utils/parallel"]
 wasm = ["wasmer/js", "wasmer/std"]
 fullmerkletree = ["default"]
 

rln/src/ffi.rs

@@ -12,15 +12,7 @@ macro_rules! call {
     ($instance:expr, $method:ident $(, $arg:expr)*) => {
         {
             let new_instance: &mut RLN = $instance.process();
-            match new_instance.$method($($arg.process()),*) {
-                Ok(()) => {
-                    true
-                }
-                Err(err) => {
-                    eprintln!("execution error: {err}");
-                    false
-                }
-            }
+            new_instance.$method($($arg.process()),*).is_ok()
         }
     }
 }
@@ -38,17 +30,13 @@ macro_rules! call_with_output_arg {
         {
             let mut output_data: Vec<u8> = Vec::new();
             let new_instance = $instance.process();
-            match new_instance.$method(&mut output_data) {
-                Ok(()) => {
-                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                    std::mem::forget(output_data);
-                    true
-                }
-                Err(err) => {
-                    std::mem::forget(output_data);
-                    eprintln!("execution error: {err}");
-                    false
-                }
+            if new_instance.$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
             }
         }
     };
@@ -56,17 +44,13 @@ macro_rules! call_with_output_arg {
         {
             let mut output_data: Vec<u8> = Vec::new();
             let new_instance = $instance.process();
-            match new_instance.$method($($arg.process()),*, &mut output_data) {
-                Ok(()) => {
-                    unsafe { *$output_arg = Buffer::from(&output_data[..]) };
-                    std::mem::forget(output_data);
-                    true
-                }
-                Err(err) => {
-                    std::mem::forget(output_data);
-                    eprintln!("execution error: {err}");
-                    false
-                }
+            if new_instance.$method($($arg.process()),*, &mut output_data).is_ok() {
+                unsafe { *$output_arg = Buffer::from(&output_data[..]) };
+                std::mem::forget(output_data);
+                true
+            } else {
+                std::mem::forget(output_data);
+                false
             }
         }
     };
@@ -82,17 +66,13 @@ macro_rules! no_ctx_call_with_output_arg {
     ($method:ident, $output_arg:expr, $( $arg:expr ),* ) => {
         {
             let mut output_data: Vec<u8> = Vec::new();
-            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
-                }
+            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
             }
         }
     }
@@ -109,11 +89,8 @@ macro_rules! call_with_bool_arg {
         {
             let new_instance = $instance.process();
             if match new_instance.$method($($arg.process()),*,) {
-                Ok(result) => result,
-                Err(err) => {
-                    eprintln!("execution error: {err}");
-                    return false
-                },
+                Ok(verified) => verified,
+                Err(_) => return false,
             } {
                 unsafe { *$bool_arg = true };
             } else {
@@ -194,15 +171,11 @@ 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 {
-    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
-        }
+    if let Ok(rln) = RLN::new(tree_height, input_buffer.process()) {
+        unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+        true
+    } else {
+        false
     }
 }
 
@@ -213,24 +186,18 @@ 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 {
-    match RLN::new_with_params(
+    if let Ok(rln) = RLN::new_with_params(
         tree_height,
         circom_buffer.process().to_vec(),
         zkey_buffer.process().to_vec(),
         vk_buffer.process().to_vec(),
-        tree_config.process(),
     ) {
-        Ok(rln) => {
-            unsafe { *ctx = Box::into_raw(Box::new(rln)) };
-            true
-        }
-        Err(err) => {
-            eprintln!("could not instantiate rln: {err}");
-            false
-        }
+        unsafe { *ctx = Box::into_raw(Box::new(rln)) };
+        true
+    } else {
+        false
     }
 }
 
@@ -261,12 +228,6 @@ 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 {
@@ -300,22 +261,6 @@ 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 {
@@ -361,21 +306,6 @@ pub extern "C" fn generate_rln_proof(
     call_with_output_arg!(ctx, generate_rln_proof, output_buffer, input_buffer)
 }
 
-#[allow(clippy::not_unsafe_ptr_arg_deref)]
-#[no_mangle]
-pub extern "C" fn generate_rln_proof_with_witness(
-    ctx: *mut RLN,
-    input_buffer: *const Buffer,
-    output_buffer: *mut Buffer,
-) -> bool {
-    call_with_output_arg!(
-        ctx,
-        generate_rln_proof_with_witness,
-        output_buffer,
-        input_buffer
-    )
-}
-
 #[allow(clippy::not_unsafe_ptr_arg_deref)]
 #[no_mangle]
 pub extern "C" fn verify_rln_proof(

rln/src/pm_tree_adapter.rs

@@ -197,13 +197,11 @@ impl ZerokitMerkleTree for PmTree {
         let mut indices = indices.into_iter().collect::<Vec<_>>();
         indices.sort();
 
-        match (leaves.len(), indices.len()) {
-            (0, 0) => Err(Report::msg("no leaves or indices to be removed")),
-            (1, 0) => self.set(start, leaves[0]),
-            (0, 1) => self.delete(indices[0]),
-            (_, 0) => self.set_range_with_leaves(start, leaves),
-            (0, _) => self.remove_indices(&indices),
-            (_, _) => self.remove_indices_and_set_leaves(start, leaves, &indices),
+        match (leaves.is_empty(), indices.is_empty()) {
+            (true, true) => Err(Report::msg("no leaves or indices to be removed")),
+            (false, true) => self.set_range_with_leaves(start, leaves),
+            (true, false) => self.remove_indices(indices),
+            (false, false) => self.remove_indices_and_set_leaves(start, leaves, indices),
         }
     }
 
@@ -246,8 +244,7 @@ impl ZerokitMerkleTree for PmTree {
         let data = self.tree.db.get(METADATA_KEY)?;
 
         if data.is_none() {
-            // send empty Metadata
-            return Ok(Vec::new());
+            return Err(Report::msg("metadata does not exist"));
         }
         Ok(data.unwrap())
     }
@@ -267,11 +264,18 @@ impl PmTree {
             .map_err(|e| Report::msg(e.to_string()))
     }
 
-    fn remove_indices(&mut self, indices: &[usize]) -> Result<()> {
+    fn remove_indices(&mut self, indices: Vec<usize>) -> Result<()> {
         let start = indices[0];
         let end = indices.last().unwrap() + 1;
 
-        let new_leaves = (start..end).map(|_| PmTreeHasher::default_leaf());
+        let mut new_leaves: Vec<_> = (start..end)
+            .map(|i| self.tree.get(i))
+            .collect::<Result<_, _>>()?;
+
+        new_leaves
+            .iter_mut()
+            .take(indices.len())
+            .for_each(|leaf| *leaf = PmTreeHasher::default_leaf());
 
         self.tree
             .set_range(start, new_leaves)
@@ -282,13 +286,16 @@ impl PmTree {
         &mut self,
         start: usize,
         leaves: Vec<FrOfPmTreeHasher>,
-        indices: &[usize],
+        indices: Vec<usize>,
     ) -> Result<()> {
         let min_index = *indices.first().unwrap();
         let max_index = start + leaves.len();
 
+        // Generated a placeholder with the exact size needed,
+        // Initiated with default values to be overridden throughout the method
         let mut set_values = vec![PmTreeHasher::default_leaf(); max_index - min_index];
 
+        // If the index is not in indices list, keep the original value
         for i in min_index..start {
             if !indices.contains(&i) {
                 let value = self.tree.get(i)?;
@@ -296,6 +303,7 @@ impl PmTree {
             }
         }
 
+        // Insert new leaves after 'start' position
         for (i, &leaf) in leaves.iter().enumerate() {
             set_values[start - min_index + i] = leaf;
         }

rln/src/public.rs

@@ -117,7 +117,6 @@ impl RLN<'_> {
     /// - `circom_vec`: a byte vector containing the ZK circuit (`rln.wasm`) as binary file
     /// - `zkey_vec`: a byte vector containing to the proving key (`rln_final.zkey`) as binary file
     /// - `vk_vec`: a byte vector containing to the verification key (`verification_key.json`) as binary file
-    /// - `tree_config`: a reader for a string containing a json with the merkle tree configuration
     ///
     /// Example:
     /// ```
@@ -135,8 +134,6 @@ impl RLN<'_> {
     ///     let mut buffer = vec![0; metadata.len() as usize];
     ///     file.read_exact(&mut buffer).expect("buffer overflow");
     ///     resources.push(buffer);
-    ///     let tree_config = "{}".to_string();
-    ///     let tree_config_buffer = &Buffer::from(tree_config.as_bytes());
     /// }
     ///
     /// let mut rln = RLN::new_with_params(
@@ -144,51 +141,11 @@ impl RLN<'_> {
     ///     resources[0].clone(),
     ///     resources[1].clone(),
     ///     resources[2].clone(),
-    ///     tree_config_buffer,
     /// );
     /// ```
-    #[cfg(not(target_arch = "wasm32"))]
-    pub fn new_with_params<R: Read>(
-        tree_height: usize,
-        circom_vec: Vec<u8>,
-        zkey_vec: Vec<u8>,
-        vk_vec: Vec<u8>,
-        mut tree_config_input: R,
-    ) -> Result<RLN<'static>> {
-        #[cfg(not(target_arch = "wasm32"))]
-        let witness_calculator = circom_from_raw(circom_vec)?;
-
-        let proving_key = zkey_from_raw(&zkey_vec)?;
-        let verification_key = vk_from_raw(&vk_vec, &zkey_vec)?;
-
-        let mut tree_config_vec: Vec<u8> = Vec::new();
-        tree_config_input.read_to_end(&mut tree_config_vec)?;
-        let tree_config_str = String::from_utf8(tree_config_vec)?;
-        let tree_config: <PoseidonTree as ZerokitMerkleTree>::Config = if tree_config_str.is_empty()
-        {
-            <PoseidonTree as ZerokitMerkleTree>::Config::default()
-        } else {
-            <PoseidonTree as ZerokitMerkleTree>::Config::from_str(&tree_config_str)?
-        };
-
-        // We compute a default empty tree
-        let tree = PoseidonTree::new(
-            tree_height,
-            <PoseidonTree as ZerokitMerkleTree>::Hasher::default_leaf(),
-            tree_config,
-        )?;
-
-        Ok(RLN {
-            witness_calculator,
-            proving_key,
-            verification_key,
-            tree,
-        })
-    }
-
-    #[cfg(target_arch = "wasm32")]
     pub fn new_with_params(
         tree_height: usize,
+        #[cfg(not(target_arch = "wasm32"))] circom_vec: Vec<u8>,
         zkey_vec: Vec<u8>,
         vk_vec: Vec<u8>,
     ) -> Result<RLN<'static>> {
@@ -202,9 +159,12 @@ impl RLN<'_> {
         let tree = PoseidonTree::default(tree_height)?;
 
         Ok(RLN {
+            #[cfg(not(target_arch = "wasm32"))]
+            witness_calculator,
             proving_key,
             verification_key,
             tree,
+            #[cfg(target_arch = "wasm32")]
             _marker: PhantomData,
         })
     }
@@ -406,10 +366,6 @@ impl RLN<'_> {
         Ok(())
     }
 
-    pub fn leaves_set(&mut self) -> usize {
-        self.tree.leaves_set()
-    }
-
     /// Sets a leaf value at the next available never-set leaf index.
     ///
     /// This function updates the internal Merkle tree `next_index` value indicating the next available index corresponding to a never-set leaf as `next_index = next_index + 1`.
@@ -720,9 +676,9 @@ impl RLN<'_> {
         mut output_data: W,
     ) -> Result<()> {
         // We read input RLN witness and we serialize_compressed it
-        let mut input_byte: Vec<u8> = Vec::new();
-        input_data.read_to_end(&mut input_byte)?;
-        let (rln_witness, _) = proof_inputs_to_rln_witness(&mut self.tree, &input_byte)?;
+        let mut witness_byte: Vec<u8> = Vec::new();
+        input_data.read_to_end(&mut witness_byte)?;
+        let (rln_witness, _) = proof_inputs_to_rln_witness(&mut self.tree, &witness_byte)?;
         let proof_values = proof_values_from_witness(&rln_witness);
 
         let proof = generate_proof(self.witness_calculator, &self.proving_key, &rln_witness)?;
@@ -735,33 +691,12 @@ impl RLN<'_> {
         Ok(())
     }
 
+    // TODO: this function seems to use redundant witness (as bigint and serialized) and should be refactored
     // Generate RLN Proof using a witness calculated from outside zerokit
     //
     // output_data is  [ proof<128> | root<32> | epoch<32> | share_x<32> | share_y<32> | nullifier<32> | rln_identifier<32> ]
     // we skip it from documentation for now
-    #[cfg(not(target_arch = "wasm32"))]
-    pub fn generate_rln_proof_with_witness<R: Read, W: Write>(
-        &mut self,
-        mut input_data: R,
-        mut output_data: W,
-    ) -> Result<()> {
-        let mut witness_byte: Vec<u8> = Vec::new();
-        input_data.read_to_end(&mut witness_byte)?;
-        let (rln_witness, _) = deserialize_witness(&witness_byte)?;
-        let proof_values = proof_values_from_witness(&rln_witness);
-
-        let proof = generate_proof(self.witness_calculator, &self.proving_key, &rln_witness)?;
-
-        // Note: we export a serialization of ark-groth16::Proof not semaphore::Proof
-        // This proof is compressed, i.e. 128 bytes long
-        proof.serialize_compressed(&mut output_data)?;
-        output_data.write_all(&serialize_proof_values(&proof_values))?;
-        Ok(())
-    }
-
-    // Different in wasm since witness_calculator is not available
-    // See: https://github.com/vacp2p/zerokit/blob/b903d8d740e0b8b82057bcc5377ddce05ae5676b/rln/src/public.rs#L47-L49
-    #[cfg(target_arch = "wasm32")]
+    #[doc(hidden)]
     pub fn generate_rln_proof_with_witness<W: Write>(
         &mut self,
         calculated_witness: Vec<BigInt>,
@@ -1821,10 +1756,13 @@ mod test {
             .collect();
 
         // Generating the proof
-        let mut input_buffer = Cursor::new(serialized_witness);
         let mut output_buffer = Cursor::new(Vec::<u8>::new());
-        rln.generate_rln_proof_with_witness(&mut input_buffer, &mut output_buffer)
-            .unwrap();
+        rln.generate_rln_proof_with_witness(
+            calculated_witness_vec,
+            serialized_witness,
+            &mut output_buffer,
+        )
+        .unwrap();
 
         // output_data is [ proof<128> | share_y<32> | nullifier<32> | root<32> | epoch<32> | share_x<32> | rln_identifier<32> ]
         let mut proof_data = output_buffer.into_inner();
@@ -2108,19 +2046,4 @@ mod test {
 
         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/tests/ffi.rs

@@ -143,8 +143,6 @@ mod test {
         assert!(success, "RLN object creation failed");
         let rln_pointer = unsafe { &mut *rln_pointer.assume_init() };
 
-        assert_eq!(rln_pointer.leaves_set(), 0);
-
         // We generate a vector of random leaves
         let mut leaves: Vec<Fr> = Vec::new();
         let mut rng = thread_rng();
@@ -161,7 +159,6 @@ mod test {
         let input_buffer = &Buffer::from(leaves_ser.as_ref());
         let success = init_tree_with_leaves(rln_pointer, input_buffer);
         assert!(success, "init tree with leaves call failed");
-        assert_eq!(rln_pointer.leaves_set(), no_of_leaves);
 
         // We get the root of the tree obtained adding leaves in batch
         let mut output_buffer = MaybeUninit::<Buffer>::uninit();
@@ -620,14 +617,11 @@ mod test {
 
         // Creating a RLN instance passing the raw data
         let mut rln_pointer_raw_bytes = MaybeUninit::<*mut RLN>::uninit();
-        let tree_config = "".to_string();
-        let tree_config_buffer = &Buffer::from(tree_config.as_bytes());
         let success = new_with_params(
             tree_height,
             circom_data,
             zkey_data,
             vk_data,
-            tree_config_buffer,
             rln_pointer_raw_bytes.as_mut_ptr(),
         );
         assert!(success, "RLN object creation failed");
@@ -1209,7 +1203,7 @@ mod test {
     }
 
     #[test]
-    fn test_valid_metadata() {
+    fn test_metadata() {
         // We create a RLN instance
         let tree_height = TEST_TREE_HEIGHT;
 
@@ -1235,25 +1229,4 @@ 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);
-    }
 }

semaphore/Cargo.toml

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

semaphore/Makefile.toml

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

semaphore/README.md

@@ -0,0 +1,18 @@
+# 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

@@ -0,0 +1,111 @@
+// 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

@@ -0,0 +1,79 @@
+// 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

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

semaphore/src/protocol.rs

@@ -0,0 +1,215 @@
+// 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

@@ -0,0 +1,115 @@
+#[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 = "0.3.3"
+version = "0.3.1"
 edition = "2021"
 license = "MIT OR Apache-2.0"
 description = "Various utilities for Zerokit"
@@ -13,11 +13,9 @@ bench = false
 
 [dependencies]
 ark-ff = { version = "=0.4.1", default-features = false, features = ["asm"] }
-num-bigint = { version = "=0.4.3", default-features = false, features = [
-    "rand",
-] }
+num-bigint = { version = "=0.4.3", default-features = false, features = ["rand"] }
 color-eyre = "=0.6.2"
-pmtree = { package = "pmtree", version = "=2.0.0", optional = true }
+pmtree = { package = "vacp2p_pmtree", version = "=1.0.0", optional = true}
 sled = "=0.34.7"
 serde = "=1.0.163"
 

utils/src/pm_tree/sled_adapter.rs

@@ -2,51 +2,29 @@ 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 = Self::new_with_tries(config, 0)?;
-        Ok(db)
+        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))
     }
 
     fn load(config: Self::Config) -> PmtreeResult<Self> {
-        let db = match config.open() {
+        let db: Sled = match sled::open(&config.path) {
             Ok(db) => db,
             Err(e) => {
                 return Err(PmtreeErrorKind::DatabaseError(