sonobe/examples/full_flow.rs

#![allow(non_snake_case)]
#![allow(non_camel_case_types)]
#![allow(clippy::upper_case_acronyms)]
///
/// This example performs the full flow:
/// - define the circuit to be folded
/// - fold the circuit with Nova+CycleFold's IVC
/// - generate a DeciderEthCircuit final proof
/// - generate the Solidity contract that verifies the proof
/// - verify the proof in the EVM
///
use ark_bn254::{constraints::GVar, Bn254, Fr, G1Projective as G1};
use ark_ff::PrimeField;
use ark_groth16::Groth16;
use ark_grumpkin::{constraints::GVar as GVar2, Projective as G2};
use ark_r1cs_std::alloc::AllocVar;
use ark_r1cs_std::fields::fp::FpVar;
use ark_relations::r1cs::{ConstraintSystemRef, SynthesisError};
use std::marker::PhantomData;
use std::time::Instant;

use folding_schemes::{
    commitment::{kzg::KZG, pedersen::Pedersen},
    folding::nova::{
        decider_eth::{prepare_calldata, Decider as DeciderEth},
        Nova, PreprocessorParam,
    },
    frontend::FCircuit,
    transcript::poseidon::poseidon_canonical_config,
    Decider, Error, FoldingScheme,
};
use solidity_verifiers::{
    evm::{compile_solidity, Evm},
    utils::get_function_selector_for_nova_cyclefold_verifier,
    verifiers::nova_cyclefold::get_decider_template_for_cyclefold_decider,
    NovaCycleFoldVerifierKey,
};

/// Test circuit to be folded
#[derive(Clone, Copy, Debug)]
pub struct CubicFCircuit<F: PrimeField> {
    _f: PhantomData<F>,
}
impl<F: PrimeField> FCircuit<F> for CubicFCircuit<F> {
    type Params = ();
    fn new(_params: Self::Params) -> Result<Self, Error> {
        Ok(Self { _f: PhantomData })
    }
    fn state_len(&self) -> usize {
        1
    }
    fn external_inputs_len(&self) -> usize {
        0
    }
    fn step_native(
        &self,
        _i: usize,
        z_i: Vec<F>,
        _external_inputs: Vec<F>,
    ) -> Result<Vec<F>, Error> {
        Ok(vec![z_i[0] * z_i[0] * z_i[0] + z_i[0] + F::from(5_u32)])
    }
    fn generate_step_constraints(
        &self,
        cs: ConstraintSystemRef<F>,
        _i: usize,
        z_i: Vec<FpVar<F>>,
        _external_inputs: Vec<FpVar<F>>,
    ) -> Result<Vec<FpVar<F>>, SynthesisError> {
        let five = FpVar::<F>::new_constant(cs.clone(), F::from(5u32))?;
        let z_i = z_i[0].clone();

        Ok(vec![&z_i * &z_i * &z_i + &z_i + &five])
    }
}

fn main() {
    let n_steps = 10;
    // set the initial state
    let z_0 = vec![Fr::from(3_u32)];

    let f_circuit = CubicFCircuit::<Fr>::new(()).unwrap();

    pub type N = Nova<G1, GVar, G2, GVar2, CubicFCircuit<Fr>, KZG<'static, Bn254>, Pedersen<G2>>;
    pub type D = DeciderEth<
        G1,
        GVar,
        G2,
        GVar2,
        CubicFCircuit<Fr>,
        KZG<'static, Bn254>,
        Pedersen<G2>,
        Groth16<Bn254>,
        N,
    >;

    let poseidon_config = poseidon_canonical_config::<Fr>();
    let mut rng = rand::rngs::OsRng;

    // prepare the Nova prover & verifier params
    let nova_preprocess_params = PreprocessorParam::new(poseidon_config.clone(), f_circuit);
    let (fs_pp, fs_vp) = N::preprocess(&mut rng, &nova_preprocess_params).unwrap();

    // initialize the folding scheme engine, in our case we use Nova
    let mut nova = N::init(&fs_pp, f_circuit, z_0).unwrap();

    // prepare the Decider prover & verifier params
    let (decider_pp, decider_vp) = D::preprocess(&mut rng, &(fs_pp, fs_vp), nova.clone()).unwrap();

    // run n steps of the folding iteration
    for i in 0..n_steps {
        let start = Instant::now();
        nova.prove_step(rng, vec![]).unwrap();
        println!("Nova::prove_step {}: {:?}", i, start.elapsed());
    }

    let start = Instant::now();
    let proof = D::prove(rng, decider_pp, nova.clone()).unwrap();
    println!("generated Decider proof: {:?}", start.elapsed());

    let verified = D::verify(
        decider_vp.clone(),
        nova.i,
        nova.z_0.clone(),
        nova.z_i.clone(),
        &nova.U_i,
        &nova.u_i,
        &proof,
    )
    .unwrap();
    assert!(verified);
    println!("Decider proof verification: {}", verified);

    // Now, let's generate the Solidity code that verifies this Decider final proof
    let function_selector =
        get_function_selector_for_nova_cyclefold_verifier(nova.z_0.len() * 2 + 1);

    let calldata: Vec<u8> = prepare_calldata(
        function_selector,
        nova.i,
        nova.z_0,
        nova.z_i,
        &nova.U_i,
        &nova.u_i,
        proof,
    )
    .unwrap();

    // prepare the setup params for the solidity verifier
    let nova_cyclefold_vk = NovaCycleFoldVerifierKey::from((decider_vp, f_circuit.state_len()));

    // generate the solidity code
    let decider_solidity_code = get_decider_template_for_cyclefold_decider(nova_cyclefold_vk);

    // verify the proof against the solidity code in the EVM
    let nova_cyclefold_verifier_bytecode = compile_solidity(&decider_solidity_code, "NovaDecider");
    let mut evm = Evm::default();
    let verifier_address = evm.create(nova_cyclefold_verifier_bytecode);
    let (_, output) = evm.call(verifier_address, calldata.clone());
    assert_eq!(*output.last().unwrap(), 1);

    // save smart contract and the calldata
    println!("storing nova-verifier.sol and the calldata into files");
    use std::fs;
    fs::write(
        "./examples/nova-verifier.sol",
        decider_solidity_code.clone(),
    )
    .unwrap();
    fs::write("./examples/solidity-calldata.calldata", calldata.clone()).unwrap();
    let s = solidity_verifiers::utils::get_formatted_calldata(calldata.clone());
    fs::write("./examples/solidity-calldata.inputs", s.join(",\n")).expect("");
}