Revert "remove multiplier (#184)" (#185)

This reverts commit 4ec93c5e1f.

.github/workflows/ci.yml

@@ -5,6 +5,7 @@ on:
     paths-ignore:
       - '**.md'
       - '!.github/workflows/*.yml'
+      - '!multiplier/src/**'
       - '!private-settlement/src/**'
       - '!rln-wasm/**'
       - '!rln/src/**'
@@ -15,6 +16,7 @@ on:
     paths-ignore:
       - '**.md'
       - '!.github/workflows/*.yml'
+      - '!multiplier/src/**'
       - '!private-settlement/src/**'
       - '!rln-wasm/**'
       - '!rln/src/**'
@@ -30,7 +32,7 @@ jobs:
     strategy:
       matrix:
         platform: [ubuntu-latest, macos-latest]
-        crate: [semaphore, rln, utils]
+        crate: [multiplier, semaphore, rln, utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
   
@@ -83,7 +85,7 @@ jobs:
       matrix:
         # we run lint tests only on ubuntu
         platform: [ubuntu-latest]
-        crate: [semaphore, rln, utils]
+        crate: [multiplier, semaphore, rln, utils]
     runs-on: ${{ matrix.platform }}
     timeout-minutes: 60
 

Cargo.lock

@@ -1532,8 +1532,7 @@ dependencies = [
 [[package]]
 name = "ethers-core"
 version = "2.0.8"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "60ca2514feb98918a0a31de7e1983c29f2267ebf61b2dc5d4294f91e5b866623"
+source = "git+https://github.com/gakonst/ethers-rs?rev=030bf43#030bf439a100dcacd2e968e3114de0612229056b"
 dependencies = [
  "arrayvec",
  "bytes",
@@ -2078,6 +2077,18 @@ version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7843ec2de400bcbc6a6328c958dc38e5359da6e93e72e37bc5246bf1ae776389"
 
+[[package]]
+name = "multiplier"
+version = "0.1.0"
+dependencies = [
+ "ark-bn254 0.3.0",
+ "ark-circom 0.1.0 (git+https://github.com/gakonst/ark-circom?rev=35ce5a9)",
+ "ark-groth16 0.3.0",
+ "ark-serialize 0.3.0",
+ "ark-std 0.3.0",
+ "color-eyre 0.6.2",
+]
+
 [[package]]
 name = "num"
 version = "0.4.0"

Cargo.toml

@@ -1,5 +1,6 @@
 [workspace]
 members = [
+  "multiplier",
   "private-settlement",
   "semaphore",
   "rln",

multiplier/Cargo.toml

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

multiplier/Makefile.toml

@@ -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);
+    }
+}