Full flow example (#90)

* expose params & structs for external usage

* add full_flow example, move examples into 'examples' dir

.github/workflows/ci.yml

@@ -79,6 +79,10 @@ jobs:
     steps:
       - uses: actions/checkout@v2
       - uses: actions-rs/toolchain@v1
+      - name: Download solc
+        run: |
+          curl -sSfL https://github.com/ethereum/solidity/releases/download/v0.8.4/solc-static-linux -o /usr/local/bin/solc
+          chmod +x /usr/local/bin/solc
       - name: Run examples tests
         run: cargo test --examples
       - name: Run examples

.gitignore

@@ -7,3 +7,6 @@ folding-schemes/src/frontend/circom/test_folder/cubic_circuit_js/
 
 # generated contracts at test time
 solidity-verifiers/generated
+examples/*.sol
+examples/*.calldata
+examples/*.inputs

examples/full_flow.rs

@@ -0,0 +1,222 @@
+#![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_crypto_primitives::snark::SNARK;
+use ark_ff::PrimeField;
+use ark_groth16::VerifyingKey as G16VerifierKey;
+use ark_groth16::{Groth16, ProvingKey};
+use ark_grumpkin::{constraints::GVar as GVar2, Projective as G2};
+use ark_poly_commit::kzg10::VerifierKey as KZGVerifierKey;
+use ark_r1cs_std::alloc::AllocVar;
+use ark_r1cs_std::fields::fp::FpVar;
+use ark_relations::r1cs::{ConstraintSystemRef, SynthesisError};
+use ark_std::Zero;
+use std::marker::PhantomData;
+use std::time::Instant;
+
+use folding_schemes::{
+    commitment::{
+        kzg::{ProverKey as KZGProverKey, KZG},
+        pedersen::Pedersen,
+        CommitmentScheme,
+    },
+    folding::nova::{
+        decider_eth::{prepare_calldata, Decider as DeciderEth},
+        decider_eth_circuit::DeciderEthCircuit,
+        get_cs_params_len, Nova, ProverParams,
+    },
+    frontend::FCircuit,
+    transcript::poseidon::poseidon_test_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) -> Self {
+        Self { _f: PhantomData }
+    }
+    fn state_len(&self) -> usize {
+        1
+    }
+    fn step_native(&self, _i: usize, z_i: 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>>,
+    ) -> 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])
+    }
+}
+
+#[allow(clippy::type_complexity)]
+fn init_test_prover_params<FC: FCircuit<Fr, Params = ()>>() -> (
+    ProverParams<G1, G2, KZG<'static, Bn254>, Pedersen<G2>>,
+    KZGVerifierKey<Bn254>,
+) {
+    let mut rng = ark_std::test_rng();
+    let poseidon_config = poseidon_test_config::<Fr>();
+    let f_circuit = FC::new(());
+    let (cs_len, cf_cs_len) =
+        get_cs_params_len::<G1, GVar, G2, GVar2, FC>(&poseidon_config, f_circuit).unwrap();
+    let (kzg_pk, kzg_vk): (KZGProverKey<G1>, KZGVerifierKey<Bn254>) =
+        KZG::<Bn254>::setup(&mut rng, cs_len).unwrap();
+    let (cf_pedersen_params, _) = Pedersen::<G2>::setup(&mut rng, cf_cs_len).unwrap();
+    let fs_prover_params = ProverParams::<G1, G2, KZG<Bn254>, Pedersen<G2>> {
+        poseidon_config: poseidon_config.clone(),
+        cs_params: kzg_pk.clone(),
+        cf_cs_params: cf_pedersen_params,
+    };
+    (fs_prover_params, kzg_vk)
+}
+/// Initializes Nova parameters and DeciderEth parameters. Only for test purposes.
+#[allow(clippy::type_complexity)]
+fn init_params<FC: FCircuit<Fr, Params = ()>>() -> (
+    ProverParams<G1, G2, KZG<'static, Bn254>, Pedersen<G2>>,
+    KZGVerifierKey<Bn254>,
+    ProvingKey<Bn254>,
+    G16VerifierKey<Bn254>,
+) {
+    let mut rng = rand::rngs::OsRng;
+    let start = Instant::now();
+    let (fs_prover_params, kzg_vk) = init_test_prover_params::<FC>();
+    println!("generated Nova folding params: {:?}", start.elapsed());
+    let f_circuit = FC::new(());
+
+    pub type NOVA<FC> = Nova<G1, GVar, G2, GVar2, FC, KZG<'static, Bn254>, Pedersen<G2>>;
+    let z_0 = vec![Fr::zero(); f_circuit.state_len()];
+    let nova = NOVA::init(&fs_prover_params, f_circuit, z_0.clone()).unwrap();
+
+    let decider_circuit =
+        DeciderEthCircuit::<G1, GVar, G2, GVar2, KZG<Bn254>, Pedersen<G2>>::from_nova::<FC>(
+            nova.clone(),
+        )
+        .unwrap();
+    let start = Instant::now();
+    let (g16_pk, g16_vk) =
+        Groth16::<Bn254>::circuit_specific_setup(decider_circuit.clone(), &mut rng).unwrap();
+    println!(
+        "generated G16 (Decider circuit) params: {:?}",
+        start.elapsed()
+    );
+    (fs_prover_params, kzg_vk, g16_pk, g16_vk)
+}
+
+fn main() {
+    let n_steps = 10;
+    // set the initial state
+    let z_0 = vec![Fr::from(3_u32)];
+
+    let (fs_prover_params, kzg_vk, g16_pk, g16_vk) = init_params::<CubicFCircuit<Fr>>();
+
+    pub type NOVA = Nova<G1, GVar, G2, GVar2, CubicFCircuit<Fr>, KZG<'static, Bn254>, Pedersen<G2>>;
+    pub type DECIDERETH_FCircuit = DeciderEth<
+        G1,
+        GVar,
+        G2,
+        GVar2,
+        CubicFCircuit<Fr>,
+        KZG<'static, Bn254>,
+        Pedersen<G2>,
+        Groth16<Bn254>,
+        NOVA,
+    >;
+    let f_circuit = CubicFCircuit::<Fr>::new(());
+
+    // initialize the folding scheme engine, in our case we use Nova
+    let mut nova = NOVA::init(&fs_prover_params, f_circuit, z_0).unwrap();
+    // run n steps of the folding iteration
+    for i in 0..n_steps {
+        let start = Instant::now();
+        nova.prove_step().unwrap();
+        println!("Nova::prove_step {}: {:?}", i, start.elapsed());
+    }
+
+    let rng = rand::rngs::OsRng;
+    let start = Instant::now();
+    let proof = DECIDERETH_FCircuit::prove(
+        (g16_pk, fs_prover_params.cs_params.clone()),
+        rng,
+        nova.clone(),
+    )
+    .unwrap();
+    println!("generated Decider proof: {:?}", start.elapsed());
+
+    let verified = DECIDERETH_FCircuit::verify(
+        (g16_vk.clone(), kzg_vk.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((g16_vk, kzg_vk, 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("");
+}

examples/utils.rs

@@ -11,7 +11,7 @@ use folding_schemes::folding::nova::{get_r1cs, ProverParams, VerifierParams};
 use folding_schemes::frontend::FCircuit;
 use folding_schemes::transcript::poseidon::poseidon_test_config;
 
-// This method computes the Prover & Verifier parameters for the example.
+// This method computes the Nova's Prover & Verifier parameters for the example.
 // Warning: this method is only for testing purposes. For a real world use case those parameters
 // should be generated carefully (both the PoseidonConfig and the PedersenParams).
 #[allow(clippy::type_complexity)]

folding-schemes/Cargo.toml

@@ -47,3 +47,16 @@ parallel = [
     "ark-crypto-primitives/parallel",  
     "ark-r1cs-std/parallel",  
     ]
+
+
+[[example]]
+name = "sha256"
+path = "../examples/sha256.rs"
+
+[[example]]
+name = "multi_inputs"
+path = "../examples/multi_inputs.rs"
+
+[[example]]
+name = "external_inputs"
+path = "../examples/external_inputs.rs"

folding-schemes/src/frontend/circom/mod.rs

@@ -83,7 +83,7 @@ impl<F: PrimeField> FCircuit<F> for CircomFCircuit<F> {
         let circom_circuit = CircomCircuit {
             r1cs,
             witness: witness.clone(),
-            inputs_already_computed: true,
+            inputs_already_allocated: true,
         };
 
         // Generates the constraints for the circom_circuit.

folding-schemes/src/frontend/circom/utils.rs

@@ -140,7 +140,7 @@ mod tests {
         let circom_circuit = CircomCircuit {
             r1cs,
             witness,
-            inputs_already_computed: false,
+            inputs_already_allocated: false,
         };
 
         circom_circuit.generate_constraints(cs.clone()).unwrap();

folding-schemes/src/frontend/mod.rs

@@ -52,10 +52,9 @@ pub mod tests {
     use core::marker::PhantomData;
 
     /// CubicFCircuit is a struct that implements the FCircuit trait, for the R1CS example circuit
-    /// from https://www.vitalik.ca/general/2016/12/10/qap.html, which checks `x^3 + x + 5 = y`. It
+    /// from https://www.vitalik.ca/general/2016/12/10/qap.html, which checks `x^3 + x + 5 = y`.
-    /// has 2 public inputs which are used as the state. `z_i` is used as `x`, and `z_{i+1}` is
+    /// `z_i` is used as `x`, and `z_{i+1}` is used as `y`, and at the next step, `z_{i+1}` will be
-    /// used as `y`, and at the next step, `z_{i+1}` will be assigned to `z_i`, and a new `z+{i+1}`
+    /// assigned to `z_i`, and a new `z+{i+1}` will be computted.
-    /// will be computted.
     #[derive(Clone, Copy, Debug)]
     pub struct CubicFCircuit<F: PrimeField> {
         _f: PhantomData<F>,

solidity-verifiers/Cargo.toml

@@ -40,4 +40,7 @@ parallel = [
     ]
 
 
-
+[[example]]
+name = "full_flow"
+path = "../examples/full_flow.rs"
+# required-features = ["light-test"]

solidity-verifiers/src/verifiers/g16.rs

@@ -11,19 +11,19 @@ use super::PRAGMA_GROTH16_VERIFIER;
 
 #[derive(Template, Default)]
 #[template(path = "groth16_verifier.askama.sol", ext = "sol")]
-pub(crate) struct Groth16Verifier {
+pub struct Groth16Verifier {
     /// The `alpha * G`, where `G` is the generator of `G1`.
-    pub(crate) vkey_alpha_g1: G1Repr,
+    pub vkey_alpha_g1: G1Repr,
     /// The `alpha * H`, where `H` is the generator of `G2`.
-    pub(crate) vkey_beta_g2: G2Repr,
+    pub vkey_beta_g2: G2Repr,
     /// The `gamma * H`, where `H` is the generator of `G2`.
-    pub(crate) vkey_gamma_g2: G2Repr,
+    pub vkey_gamma_g2: G2Repr,
     /// The `delta * H`, where `H` is the generator of `G2`.
-    pub(crate) vkey_delta_g2: G2Repr,
+    pub vkey_delta_g2: G2Repr,
     /// Length of the `gamma_abc_g1` vector.
-    pub(crate) gamma_abc_len: usize,
+    pub gamma_abc_len: usize,
     /// The `gamma^{-1} * (beta * a_i + alpha * b_i + c_i) * H`, where `H` is the generator of `E::G1`.
-    pub(crate) gamma_abc_g1: Vec<G1Repr>,
+    pub gamma_abc_g1: Vec<G1Repr>,
 }
 
 impl From<Groth16VerifierKey> for Groth16Verifier {

solidity-verifiers/src/verifiers/kzg.rs

@@ -11,7 +11,7 @@ use super::PRAGMA_KZG10_VERIFIER;
 
 #[derive(Template, Default)]
 #[template(path = "kzg10_verifier.askama.sol", ext = "sol")]
-pub(crate) struct KZG10Verifier {
+pub struct KZG10Verifier {
     /// The generator of `G1`.
     pub(crate) g1: G1Repr,
     /// The generator of `G2`.
@@ -42,8 +42,8 @@ impl From<KZG10VerifierKey> for KZG10Verifier {
 
 #[derive(CanonicalDeserialize, CanonicalSerialize, Clone, PartialEq, Debug)]
 pub struct KZG10VerifierKey {
-    pub(crate) vk: VerifierKey<Bn254>,
+    pub vk: VerifierKey<Bn254>,
-    pub(crate) g1_crs_batch_points: Vec<G1Affine>,
+    pub g1_crs_batch_points: Vec<G1Affine>,
 }
 
 impl From<(VerifierKey<Bn254>, Vec<G1Affine>)> for KZG10VerifierKey {

solidity-verifiers/src/verifiers/mod.rs

@@ -2,17 +2,17 @@
 //! We use askama for templating and define which variables are required for each template.
 
 // Pragma statements for verifiers
-pub(crate) const PRAGMA_GROTH16_VERIFIER: &str = "pragma solidity >=0.7.0 <0.9.0;"; // from snarkjs, avoid changing
+pub const PRAGMA_GROTH16_VERIFIER: &str = "pragma solidity >=0.7.0 <0.9.0;"; // from snarkjs, avoid changing
-pub(crate) const PRAGMA_KZG10_VERIFIER: &str = "pragma solidity >=0.8.1 <=0.8.4;";
+pub const PRAGMA_KZG10_VERIFIER: &str = "pragma solidity >=0.8.1 <=0.8.4;";
 
 /// Default SDPX License identifier
-pub(crate) const GPL3_SDPX_IDENTIFIER: &str = "// SPDX-License-Identifier: GPL-3.0";
+pub const GPL3_SDPX_IDENTIFIER: &str = "// SPDX-License-Identifier: GPL-3.0";
-pub(crate) const MIT_SDPX_IDENTIFIER: &str = "// SPDX-License-Identifier: MIT";
+pub const MIT_SDPX_IDENTIFIER: &str = "// SPDX-License-Identifier: MIT";
 use ark_serialize::{CanonicalDeserialize, CanonicalSerialize, Read, SerializationError, Write};
 
-mod g16;
+pub mod g16;
-mod kzg;
+pub mod kzg;
-mod nova_cyclefold;
+pub mod nova_cyclefold;
 
 pub use g16::Groth16VerifierKey;
 pub use kzg::KZG10VerifierKey;

solidity-verifiers/src/verifiers/nova_cyclefold.rs

@@ -26,7 +26,7 @@ pub fn get_decider_template_for_cyclefold_decider(
 
 #[derive(Template, Default)]
 #[template(path = "nova_cyclefold_decider.askama.sol", ext = "sol")]
-pub(crate) struct NovaCycleFoldDecider {
+pub struct NovaCycleFoldDecider {
     groth16_verifier: Groth16Verifier,
     kzg10_verifier: KZG10Verifier,
     // z_len denotes the FCircuit state (z_i) length