diff --git a/Cargo.toml b/Cargo.toml index 08e02a7..b78f73b 100644 --- a/Cargo.toml +++ b/Cargo.toml @@ -1,6 +1,6 @@ [package] name = "nova-snark" -version = "0.6.1" +version = "0.7.0" authors = ["Srinath Setty "] edition = "2021" description = "Recursive zkSNARKs without trusted setup" diff --git a/benches/compressed-snark.rs b/benches/compressed-snark.rs index 6b2a20a..8133e76 100644 --- a/benches/compressed-snark.rs +++ b/benches/compressed-snark.rs @@ -10,6 +10,31 @@ type G2 = pasta_curves::vesta::Point; type S1 = nova_snark::spartan_with_ipa_pc::RelaxedR1CSSNARK; type S2 = nova_snark::spartan_with_ipa_pc::RelaxedR1CSSNARK; +#[derive(Clone, Debug)] +struct TrivialTestCircuit { + _p: PhantomData, +} + +impl StepCircuit for TrivialTestCircuit +where + F: PrimeField, +{ + fn synthesize>( + &self, + _cs: &mut CS, + z: AllocatedNum, + ) -> Result, SynthesisError> { + Ok(z) + } + + fn compute(&self, z: &F) -> F { + *z + } +} + +type C1 = TrivialTestCircuit<::Scalar>; +type C2 = TrivialTestCircuit<::Scalar>; + use bellperson::{gadgets::num::AllocatedNum, ConstraintSystem, SynthesisError}; use core::marker::PhantomData; use criterion::*; @@ -18,8 +43,7 @@ use std::time::Duration; fn compressed_snark_benchmark(c: &mut Criterion) { let num_samples = 10; - let num_steps = 3; - bench_compressed_snark(c, num_samples, num_steps); + bench_compressed_snark(c, num_samples); } fn set_duration() -> Criterion { @@ -34,16 +58,12 @@ targets = compressed_snark_benchmark criterion_main!(compressed_snark); -fn bench_compressed_snark(c: &mut Criterion, num_samples: usize, num_steps: usize) { +fn bench_compressed_snark(c: &mut Criterion, num_samples: usize) { let mut group = c.benchmark_group("CompressedSNARK"); group.sample_size(num_samples); + // Produce public parameters - let pp = PublicParams::< - G1, - G2, - TrivialTestCircuit<::Scalar>, - TrivialTestCircuit<::Scalar>, - >::setup( + let pp = PublicParams::::setup( TrivialTestCircuit { _p: Default::default(), }, @@ -53,15 +73,40 @@ fn bench_compressed_snark(c: &mut Criterion, num_samples: usize, num_steps: usiz ); // produce a recursive SNARK - let res = RecursiveSNARK::prove( - &pp, - num_steps, - ::Scalar::zero(), - ::Scalar::zero(), - ); - assert!(res.is_ok()); - let recursive_snark = res.unwrap(); + let num_steps = 3; + let mut recursive_snark: Option> = None; + + for i in 0..num_steps { + let res = RecursiveSNARK::prove_step( + &pp, + recursive_snark, + TrivialTestCircuit { + _p: Default::default(), + }, + TrivialTestCircuit { + _p: Default::default(), + }, + ::Scalar::one(), + ::Scalar::zero(), + ); + assert!(res.is_ok()); + let recursive_snark_unwrapped = res.unwrap(); + + // verify the recursive snark at each step of recursion + let res = recursive_snark_unwrapped.verify( + &pp, + i + 1, + ::Scalar::one(), + ::Scalar::zero(), + ); + assert!(res.is_ok()); + + // set the running variable for the next iteration + recursive_snark = Some(recursive_snark_unwrapped); + } + // Bench time to produce a compressed SNARK + let recursive_snark = recursive_snark.unwrap(); group.bench_function("Prove", |b| { b.iter(|| { assert!(CompressedSNARK::<_, _, _, _, S1, S2>::prove( @@ -92,25 +137,3 @@ fn bench_compressed_snark(c: &mut Criterion, num_samples: usize, num_steps: usiz group.finish(); } - -#[derive(Clone, Debug)] -struct TrivialTestCircuit { - _p: PhantomData, -} - -impl StepCircuit for TrivialTestCircuit -where - F: PrimeField, -{ - fn synthesize>( - &self, - _cs: &mut CS, - z: AllocatedNum, - ) -> Result, SynthesisError> { - Ok(z) - } - - fn compute(&self, z: &F) -> F { - *z - } -} diff --git a/benches/recursive-snark.rs b/benches/recursive-snark.rs index f91e3cd..761645e 100644 --- a/benches/recursive-snark.rs +++ b/benches/recursive-snark.rs @@ -8,6 +8,31 @@ use nova_snark::{ type G1 = pasta_curves::pallas::Point; type G2 = pasta_curves::vesta::Point; +#[derive(Clone, Debug)] +struct TrivialTestCircuit { + _p: PhantomData, +} + +impl StepCircuit for TrivialTestCircuit +where + F: PrimeField, +{ + fn synthesize>( + &self, + _cs: &mut CS, + z: AllocatedNum, + ) -> Result, SynthesisError> { + Ok(z) + } + + fn compute(&self, z: &F) -> F { + *z + } +} + +type C1 = TrivialTestCircuit<::Scalar>; +type C2 = TrivialTestCircuit<::Scalar>; + use bellperson::{gadgets::num::AllocatedNum, ConstraintSystem, SynthesisError}; use core::marker::PhantomData; use criterion::*; @@ -16,9 +41,7 @@ use std::time::Duration; fn recursive_snark_benchmark(c: &mut Criterion) { let num_samples = 10; - for num_steps in 1..10 { - bench_recursive_snark(c, num_samples, num_steps); - } + bench_recursive_snark(c, num_samples); } fn set_duration() -> Criterion { @@ -33,16 +56,12 @@ targets = recursive_snark_benchmark criterion_main!(recursive_snark); -fn bench_recursive_snark(c: &mut Criterion, num_samples: usize, num_steps: usize) { - let mut group = c.benchmark_group(format!("RecursiveSNARK-NumSteps-{}", num_steps)); +fn bench_recursive_snark(c: &mut Criterion, num_samples: usize) { + let mut group = c.benchmark_group("RecursiveSNARK".to_string()); group.sample_size(num_samples); + // Produce public parameters - let pp = PublicParams::< - G1, - G2, - TrivialTestCircuit<::Scalar>, - TrivialTestCircuit<::Scalar>, - >::setup( + let pp = PublicParams::::setup( TrivialTestCircuit { _p: Default::default(), }, @@ -50,27 +69,63 @@ fn bench_recursive_snark(c: &mut Criterion, num_samples: usize, num_steps: usize _p: Default::default(), }, ); - // Bench time to produce a recursive SNARK + + // Bench time to produce a recursive SNARK; + // we execute a certain number of warm-up steps since executing + // the first step is cheaper than other steps owing to the presence of + // a lot of zeros in the satisfying assignment + let num_warmup_steps = 10; + let mut recursive_snark: Option> = None; + + for i in 0..num_warmup_steps { + let res = RecursiveSNARK::prove_step( + &pp, + recursive_snark, + TrivialTestCircuit { + _p: Default::default(), + }, + TrivialTestCircuit { + _p: Default::default(), + }, + ::Scalar::one(), + ::Scalar::zero(), + ); + assert!(res.is_ok()); + let recursive_snark_unwrapped = res.unwrap(); + + // verify the recursive snark at each step of recursion + let res = recursive_snark_unwrapped.verify( + &pp, + i + 1, + ::Scalar::one(), + ::Scalar::zero(), + ); + assert!(res.is_ok()); + + // set the running variable for the next iteration + recursive_snark = Some(recursive_snark_unwrapped); + } + group.bench_function("Prove", |b| { b.iter(|| { - // produce a recursive SNARK - assert!(RecursiveSNARK::prove( + // produce a recursive SNARK for a step of the recursion + assert!(RecursiveSNARK::prove_step( black_box(&pp), - black_box(num_steps), + black_box(recursive_snark.clone()), + black_box(TrivialTestCircuit { + _p: Default::default(), + }), + black_box(TrivialTestCircuit { + _p: Default::default(), + }), black_box(::Scalar::zero()), black_box(::Scalar::zero()), ) .is_ok()); }) }); - let res = RecursiveSNARK::prove( - &pp, - num_steps, - ::Scalar::zero(), - ::Scalar::zero(), - ); - assert!(res.is_ok()); - let recursive_snark = res.unwrap(); + + let recursive_snark = recursive_snark.unwrap(); // Benchmark the verification time let name = "Verify"; @@ -79,7 +134,7 @@ fn bench_recursive_snark(c: &mut Criterion, num_samples: usize, num_steps: usize assert!(black_box(&recursive_snark) .verify( black_box(&pp), - black_box(num_steps), + black_box(num_warmup_steps), black_box(::Scalar::zero()), black_box(::Scalar::zero()), ) @@ -88,25 +143,3 @@ fn bench_recursive_snark(c: &mut Criterion, num_samples: usize, num_steps: usize }); group.finish(); } - -#[derive(Clone, Debug)] -struct TrivialTestCircuit { - _p: PhantomData, -} - -impl StepCircuit for TrivialTestCircuit -where - F: PrimeField, -{ - fn synthesize>( - &self, - _cs: &mut CS, - z: AllocatedNum, - ) -> Result, SynthesisError> { - Ok(z) - } - - fn compute(&self, z: &F) -> F { - *z - } -} diff --git a/src/lib.rs b/src/lib.rs index acf39ab..52354e5 100644 --- a/src/lib.rs +++ b/src/lib.rs @@ -60,10 +60,10 @@ where r1cs_gens_secondary: R1CSGens, r1cs_shape_secondary: R1CSShape, r1cs_shape_padded_secondary: R1CSShape, - c_primary: C1, - c_secondary: C2, - params_primary: NIFSVerifierCircuitParams, - params_secondary: NIFSVerifierCircuitParams, + nifs_params_primary: NIFSVerifierCircuitParams, + nifs_params_secondary: NIFSVerifierCircuitParams, + _p_c1: PhantomData, + _p_c2: PhantomData, } impl PublicParams @@ -75,8 +75,8 @@ where { /// Create a new `PublicParams` pub fn setup(c_primary: C1, c_secondary: C2) -> Self { - let params_primary = NIFSVerifierCircuitParams::new(BN_LIMB_WIDTH, BN_N_LIMBS, true); - let params_secondary = NIFSVerifierCircuitParams::new(BN_LIMB_WIDTH, BN_N_LIMBS, false); + let nifs_params_primary = NIFSVerifierCircuitParams::new(BN_LIMB_WIDTH, BN_N_LIMBS, true); + let nifs_params_secondary = NIFSVerifierCircuitParams::new(BN_LIMB_WIDTH, BN_N_LIMBS, false); let ro_consts_primary: HashFuncConstants = HashFuncConstants::::new(); let ro_consts_secondary: HashFuncConstants = HashFuncConstants::::new(); @@ -89,9 +89,9 @@ where // Initialize gens for the primary let circuit_primary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( - params_primary.clone(), + nifs_params_primary.clone(), None, - c_primary.clone(), + c_primary, ro_consts_circuit_primary.clone(), ); let mut cs: ShapeCS = ShapeCS::new(); @@ -101,9 +101,9 @@ where // Initialize gens for the secondary let circuit_secondary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( - params_secondary.clone(), + nifs_params_secondary.clone(), None, - c_secondary.clone(), + c_secondary, ro_consts_circuit_secondary.clone(), ); let mut cs: ShapeCS = ShapeCS::new(); @@ -122,15 +122,16 @@ where r1cs_gens_secondary, r1cs_shape_secondary, r1cs_shape_padded_secondary, - c_primary, - c_secondary, - params_primary, - params_secondary, + nifs_params_primary, + nifs_params_secondary, + _p_c1: Default::default(), + _p_c2: Default::default(), } } } /// A SNARK that proves the correct execution of an incremental computation +#[derive(Clone, Debug)] pub struct RecursiveSNARK where G1: Group::Scalar>, @@ -146,8 +147,9 @@ where r_U_secondary: RelaxedR1CSInstance, l_w_secondary: R1CSWitness, l_u_secondary: R1CSInstance, - zn_primary: G1::Scalar, - zn_secondary: G2::Scalar, + i: usize, + zi_primary: G1::Scalar, + zi_secondary: G2::Scalar, _p_c1: PhantomData, _p_c2: PhantomData, } @@ -159,175 +161,191 @@ where C1: StepCircuit, C2: StepCircuit, { - /// Create a new `RecursiveSNARK` - pub fn prove( + /// Create a new `RecursiveSNARK` (or updates the provided `RecursiveSNARK`) + /// by executing a step of the incremental computation + pub fn prove_step( pp: &PublicParams, - num_steps: usize, + recursive_snark: Option, + c_primary: C1, + c_secondary: C2, z0_primary: G1::Scalar, z0_secondary: G2::Scalar, ) -> Result { - if num_steps == 0 { - return Err(NovaError::InvalidNumSteps); - } - - // Execute the base case for the primary - let mut cs_primary: SatisfyingAssignment = SatisfyingAssignment::new(); - let inputs_primary: NIFSVerifierCircuitInputs = NIFSVerifierCircuitInputs::new( - pp.r1cs_shape_secondary.get_digest(), - G1::Scalar::zero(), - z0_primary, - None, - None, - None, - None, - ); - let circuit_primary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( - pp.params_primary.clone(), - Some(inputs_primary), - pp.c_primary.clone(), - pp.ro_consts_circuit_primary.clone(), - ); - let _ = circuit_primary.synthesize(&mut cs_primary); - let (u_primary, w_primary) = cs_primary - .r1cs_instance_and_witness(&pp.r1cs_shape_primary, &pp.r1cs_gens_primary) - .map_err(|_e| NovaError::UnSat)?; - - // Execute the base case for the secondary - let mut cs_secondary: SatisfyingAssignment = SatisfyingAssignment::new(); - let inputs_secondary: NIFSVerifierCircuitInputs = NIFSVerifierCircuitInputs::new( - pp.r1cs_shape_primary.get_digest(), - G2::Scalar::zero(), - z0_secondary, - None, - None, - Some(u_primary.clone()), - None, - ); - let circuit_secondary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( - pp.params_secondary.clone(), - Some(inputs_secondary), - pp.c_secondary.clone(), - pp.ro_consts_circuit_secondary.clone(), - ); - let _ = circuit_secondary.synthesize(&mut cs_secondary); - let (u_secondary, w_secondary) = cs_secondary - .r1cs_instance_and_witness(&pp.r1cs_shape_secondary, &pp.r1cs_gens_secondary) - .map_err(|_e| NovaError::UnSat)?; - - // execute the remaining steps, alternating between G1 and G2 - let mut l_w_primary = w_primary; - let mut l_u_primary = u_primary; - let mut r_W_primary = - RelaxedR1CSWitness::from_r1cs_witness(&pp.r1cs_shape_primary, &l_w_primary); - let mut r_U_primary = RelaxedR1CSInstance::from_r1cs_instance( - &pp.r1cs_gens_primary, - &pp.r1cs_shape_primary, - &l_u_primary, - ); - - let mut r_W_secondary = RelaxedR1CSWitness::::default(&pp.r1cs_shape_secondary); - let mut r_U_secondary = - RelaxedR1CSInstance::::default(&pp.r1cs_gens_secondary, &pp.r1cs_shape_secondary); - let mut l_w_secondary = w_secondary; - let mut l_u_secondary = u_secondary; - - let mut z_next_primary = z0_primary; - let mut z_next_secondary = z0_secondary; - z_next_primary = pp.c_primary.compute(&z_next_primary); - z_next_secondary = pp.c_secondary.compute(&z_next_secondary); - - for i in 1..num_steps { - // fold the secondary circuit's instance - let (nifs_secondary, (r_U_next_secondary, r_W_next_secondary)) = NIFS::prove( - &pp.r1cs_gens_secondary, - &pp.ro_consts_secondary, - &pp.r1cs_shape_secondary, - &r_U_secondary, - &r_W_secondary, - &l_u_secondary, - &l_w_secondary, - )?; - - let mut cs_primary: SatisfyingAssignment = SatisfyingAssignment::new(); - let inputs_primary: NIFSVerifierCircuitInputs = NIFSVerifierCircuitInputs::new( - pp.r1cs_shape_secondary.get_digest(), - G1::Scalar::from(i as u64), - z0_primary, - Some(z_next_primary), - Some(r_U_secondary), - Some(l_u_secondary), - Some(nifs_secondary.comm_T.decompress()?), - ); - - let circuit_primary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( - pp.params_primary.clone(), - Some(inputs_primary), - pp.c_primary.clone(), - pp.ro_consts_circuit_primary.clone(), - ); - let _ = circuit_primary.synthesize(&mut cs_primary); - - (l_u_primary, l_w_primary) = cs_primary - .r1cs_instance_and_witness(&pp.r1cs_shape_primary, &pp.r1cs_gens_primary) - .map_err(|_e| NovaError::UnSat)?; - - // fold the primary circuit's instance - let (nifs_primary, (r_U_next_primary, r_W_next_primary)) = NIFS::prove( - &pp.r1cs_gens_primary, - &pp.ro_consts_primary, - &pp.r1cs_shape_primary, - &r_U_primary.clone(), - &r_W_primary.clone(), - &l_u_primary.clone(), - &l_w_primary.clone(), - )?; - - let mut cs_secondary: SatisfyingAssignment = SatisfyingAssignment::new(); - let inputs_secondary: NIFSVerifierCircuitInputs = NIFSVerifierCircuitInputs::new( - pp.r1cs_shape_primary.get_digest(), - G2::Scalar::from(i as u64), - z0_secondary, - Some(z_next_secondary), - Some(r_U_primary.clone()), - Some(l_u_primary.clone()), - Some(nifs_primary.comm_T.decompress()?), - ); - - let circuit_secondary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( - pp.params_secondary.clone(), - Some(inputs_secondary), - pp.c_secondary.clone(), - pp.ro_consts_circuit_secondary.clone(), - ); - let _ = circuit_secondary.synthesize(&mut cs_secondary); - - (l_u_secondary, l_w_secondary) = cs_secondary - .r1cs_instance_and_witness(&pp.r1cs_shape_secondary, &pp.r1cs_gens_secondary) - .map_err(|_e| NovaError::UnSat)?; - - // update the running instances and witnesses - r_U_secondary = r_U_next_secondary; - r_W_secondary = r_W_next_secondary; - r_U_primary = r_U_next_primary; - r_W_primary = r_W_next_primary; - z_next_primary = pp.c_primary.compute(&z_next_primary); - z_next_secondary = pp.c_secondary.compute(&z_next_secondary); + match recursive_snark { + None => { + // base case for the primary + let mut cs_primary: SatisfyingAssignment = SatisfyingAssignment::new(); + let inputs_primary: NIFSVerifierCircuitInputs = NIFSVerifierCircuitInputs::new( + pp.r1cs_shape_secondary.get_digest(), + G1::Scalar::zero(), + z0_primary, + None, + None, + None, + None, + ); + + let circuit_primary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( + pp.nifs_params_primary.clone(), + Some(inputs_primary), + c_primary.clone(), + pp.ro_consts_circuit_primary.clone(), + ); + let _ = circuit_primary.synthesize(&mut cs_primary); + let (u_primary, w_primary) = cs_primary + .r1cs_instance_and_witness(&pp.r1cs_shape_primary, &pp.r1cs_gens_primary) + .map_err(|_e| NovaError::UnSat)?; + + // base case for the secondary + let mut cs_secondary: SatisfyingAssignment = SatisfyingAssignment::new(); + let inputs_secondary: NIFSVerifierCircuitInputs = NIFSVerifierCircuitInputs::new( + pp.r1cs_shape_primary.get_digest(), + G2::Scalar::zero(), + z0_secondary, + None, + None, + Some(u_primary.clone()), + None, + ); + let circuit_secondary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( + pp.nifs_params_secondary.clone(), + Some(inputs_secondary), + c_secondary.clone(), + pp.ro_consts_circuit_secondary.clone(), + ); + let _ = circuit_secondary.synthesize(&mut cs_secondary); + let (u_secondary, w_secondary) = cs_secondary + .r1cs_instance_and_witness(&pp.r1cs_shape_secondary, &pp.r1cs_gens_secondary) + .map_err(|_e| NovaError::UnSat)?; + + // IVC proof for the primary circuit + let l_w_primary = w_primary; + let l_u_primary = u_primary; + let r_W_primary = + RelaxedR1CSWitness::from_r1cs_witness(&pp.r1cs_shape_primary, &l_w_primary); + let r_U_primary = RelaxedR1CSInstance::from_r1cs_instance( + &pp.r1cs_gens_primary, + &pp.r1cs_shape_primary, + &l_u_primary, + ); + + // IVC proof of the secondary circuit + let l_w_secondary = w_secondary; + let l_u_secondary = u_secondary; + let r_W_secondary = RelaxedR1CSWitness::::default(&pp.r1cs_shape_secondary); + let r_U_secondary = + RelaxedR1CSInstance::::default(&pp.r1cs_gens_secondary, &pp.r1cs_shape_secondary); + + // Outputs of the two circuits thus far + let zi_primary = c_primary.compute(&z0_primary); + let zi_secondary = c_secondary.compute(&z0_secondary); + + Ok(Self { + r_W_primary, + r_U_primary, + l_w_primary, + l_u_primary, + r_W_secondary, + r_U_secondary, + l_w_secondary, + l_u_secondary, + i: 1_usize, + zi_primary, + zi_secondary, + _p_c1: Default::default(), + _p_c2: Default::default(), + }) + } + Some(r_snark) => { + // fold the secondary circuit's instance + let (nifs_secondary, (r_U_secondary, r_W_secondary)) = NIFS::prove( + &pp.r1cs_gens_secondary, + &pp.ro_consts_secondary, + &pp.r1cs_shape_secondary, + &r_snark.r_U_secondary, + &r_snark.r_W_secondary, + &r_snark.l_u_secondary, + &r_snark.l_w_secondary, + )?; + + let mut cs_primary: SatisfyingAssignment = SatisfyingAssignment::new(); + let inputs_primary: NIFSVerifierCircuitInputs = NIFSVerifierCircuitInputs::new( + pp.r1cs_shape_secondary.get_digest(), + G1::Scalar::from(r_snark.i as u64), + z0_primary, + Some(r_snark.zi_primary), + Some(r_snark.r_U_secondary.clone()), + Some(r_snark.l_u_secondary.clone()), + Some(nifs_secondary.comm_T.decompress()?), + ); + + let circuit_primary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( + pp.nifs_params_primary.clone(), + Some(inputs_primary), + c_primary.clone(), + pp.ro_consts_circuit_primary.clone(), + ); + let _ = circuit_primary.synthesize(&mut cs_primary); + + let (l_u_primary, l_w_primary) = cs_primary + .r1cs_instance_and_witness(&pp.r1cs_shape_primary, &pp.r1cs_gens_primary) + .map_err(|_e| NovaError::UnSat)?; + + // fold the primary circuit's instance + let (nifs_primary, (r_U_primary, r_W_primary)) = NIFS::prove( + &pp.r1cs_gens_primary, + &pp.ro_consts_primary, + &pp.r1cs_shape_primary, + &r_snark.r_U_primary, + &r_snark.r_W_primary, + &l_u_primary, + &l_w_primary, + )?; + + let mut cs_secondary: SatisfyingAssignment = SatisfyingAssignment::new(); + let inputs_secondary: NIFSVerifierCircuitInputs = NIFSVerifierCircuitInputs::new( + pp.r1cs_shape_primary.get_digest(), + G2::Scalar::from(r_snark.i as u64), + z0_secondary, + Some(r_snark.zi_secondary), + Some(r_snark.r_U_primary.clone()), + Some(l_u_primary.clone()), + Some(nifs_primary.comm_T.decompress()?), + ); + + let circuit_secondary: NIFSVerifierCircuit = NIFSVerifierCircuit::new( + pp.nifs_params_secondary.clone(), + Some(inputs_secondary), + c_secondary.clone(), + pp.ro_consts_circuit_secondary.clone(), + ); + let _ = circuit_secondary.synthesize(&mut cs_secondary); + + let (l_u_secondary, l_w_secondary) = cs_secondary + .r1cs_instance_and_witness(&pp.r1cs_shape_secondary, &pp.r1cs_gens_secondary) + .map_err(|_e| NovaError::UnSat)?; + + // update the running instances and witnesses + let zi_primary = c_primary.compute(&r_snark.zi_primary); + let zi_secondary = c_secondary.compute(&r_snark.zi_secondary); + + Ok(Self { + r_W_primary, + r_U_primary, + l_w_primary, + l_u_primary, + r_W_secondary, + r_U_secondary, + l_w_secondary, + l_u_secondary, + i: r_snark.i + 1, + zi_primary, + zi_secondary, + _p_c1: Default::default(), + _p_c2: Default::default(), + }) + } } - - Ok(Self { - r_W_primary, - r_U_primary, - l_w_primary, - l_u_primary, - r_W_secondary, - r_U_secondary, - l_w_secondary, - l_u_secondary, - zn_primary: z_next_primary, - zn_secondary: z_next_secondary, - _p_c1: Default::default(), - _p_c2: Default::default(), - }) } /// Verify the correctness of the `RecursiveSNARK` @@ -343,6 +361,11 @@ where return Err(NovaError::ProofVerifyError); } + // check if the provided proof has executed num_steps + if self.i != num_steps { + return Err(NovaError::ProofVerifyError); + } + // check if the (relaxed) R1CS instances have two public outputs if self.l_u_primary.X.len() != 2 || self.l_u_secondary.X.len() != 2 @@ -358,14 +381,14 @@ where hasher.absorb(scalar_as_base::(pp.r1cs_shape_secondary.get_digest())); hasher.absorb(G1::Scalar::from(num_steps as u64)); hasher.absorb(z0_primary); - hasher.absorb(self.zn_primary); + hasher.absorb(self.zi_primary); self.r_U_secondary.absorb_in_ro(&mut hasher); let mut hasher2 = ::HashFunc::new(pp.ro_consts_primary.clone()); hasher2.absorb(scalar_as_base::(pp.r1cs_shape_primary.get_digest())); hasher2.absorb(G2::Scalar::from(num_steps as u64)); hasher2.absorb(z0_secondary); - hasher2.absorb(self.zn_secondary); + hasher2.absorb(self.zi_secondary); self.r_U_primary.absorb_in_ro(&mut hasher2); (hasher.get_hash(), hasher2.get_hash()) @@ -423,11 +446,12 @@ where res_r_secondary?; res_l_secondary?; - Ok((self.zn_primary, self.zn_secondary)) + Ok((self.zi_primary, self.zi_secondary)) } } /// A SNARK that proves the knowledge of a valid `RecursiveSNARK` +#[derive(Clone, Debug)] pub struct CompressedSNARK where G1: Group::Scalar>, @@ -533,8 +557,8 @@ where nifs_secondary, f_W_snark_secondary: f_W_snark_secondary?, - zn_primary: recursive_snark.zn_primary, - zn_secondary: recursive_snark.zn_secondary, + zn_primary: recursive_snark.zi_primary, + zn_secondary: recursive_snark.zi_secondary, _p_c1: Default::default(), _p_c2: Default::default(), @@ -720,10 +744,18 @@ mod tests { }, ); + let num_steps = 1; + // produce a recursive SNARK - let res = RecursiveSNARK::prove( + let res = RecursiveSNARK::prove_step( &pp, - 3, + None, + TrivialTestCircuit { + _p: Default::default(), + }, + TrivialTestCircuit { + _p: Default::default(), + }, ::Scalar::zero(), ::Scalar::zero(), ); @@ -733,7 +765,7 @@ mod tests { // verify the recursive SNARK let res = recursive_snark.verify( &pp, - 3, + num_steps, ::Scalar::zero(), ::Scalar::zero(), ); @@ -742,32 +774,60 @@ mod tests { #[test] fn test_ivc_nontrivial() { + let circuit_primary = TrivialTestCircuit { + _p: Default::default(), + }; + let circuit_secondary = CubicCircuit { + _p: Default::default(), + }; + // produce public parameters let pp = PublicParams::< G1, G2, TrivialTestCircuit<::Scalar>, CubicCircuit<::Scalar>, - >::setup( - TrivialTestCircuit { - _p: Default::default(), - }, - CubicCircuit { - _p: Default::default(), - }, - ); + >::setup(circuit_primary.clone(), circuit_secondary.clone()); let num_steps = 3; // produce a recursive SNARK - let res = RecursiveSNARK::prove( - &pp, - num_steps, - ::Scalar::one(), - ::Scalar::zero(), - ); - assert!(res.is_ok()); - let recursive_snark = res.unwrap(); + let mut recursive_snark: Option< + RecursiveSNARK< + G1, + G2, + TrivialTestCircuit<::Scalar>, + CubicCircuit<::Scalar>, + >, + > = None; + + for i in 0..num_steps { + let res = RecursiveSNARK::prove_step( + &pp, + recursive_snark, + circuit_primary.clone(), + circuit_secondary.clone(), + ::Scalar::one(), + ::Scalar::zero(), + ); + assert!(res.is_ok()); + let recursive_snark_unwrapped = res.unwrap(); + + // verify the recursive snark at each step of recursion + let res = recursive_snark_unwrapped.verify( + &pp, + i + 1, + ::Scalar::one(), + ::Scalar::zero(), + ); + assert!(res.is_ok()); + + // set the running variable for the next iteration + recursive_snark = Some(recursive_snark_unwrapped); + } + + assert!(recursive_snark.is_some()); + let recursive_snark = recursive_snark.unwrap(); // verify the recursive SNARK let res = recursive_snark.verify( @@ -795,32 +855,48 @@ mod tests { #[test] fn test_ivc_nontrivial_with_compression() { + let circuit_primary = TrivialTestCircuit { + _p: Default::default(), + }; + let circuit_secondary = CubicCircuit { + _p: Default::default(), + }; + // produce public parameters let pp = PublicParams::< G1, G2, TrivialTestCircuit<::Scalar>, CubicCircuit<::Scalar>, - >::setup( - TrivialTestCircuit { - _p: Default::default(), - }, - CubicCircuit { - _p: Default::default(), - }, - ); + >::setup(circuit_primary.clone(), circuit_secondary.clone()); let num_steps = 3; // produce a recursive SNARK - let res = RecursiveSNARK::prove( - &pp, - num_steps, - ::Scalar::one(), - ::Scalar::zero(), - ); - assert!(res.is_ok()); - let recursive_snark = res.unwrap(); + let mut recursive_snark: Option< + RecursiveSNARK< + G1, + G2, + TrivialTestCircuit<::Scalar>, + CubicCircuit<::Scalar>, + >, + > = None; + + for _i in 0..num_steps { + let res = RecursiveSNARK::prove_step( + &pp, + recursive_snark, + circuit_primary.clone(), + circuit_secondary.clone(), + ::Scalar::one(), + ::Scalar::zero(), + ); + assert!(res.is_ok()); + recursive_snark = Some(res.unwrap()); + } + + assert!(recursive_snark.is_some()); + let recursive_snark = recursive_snark.unwrap(); // verify the recursive SNARK let res = recursive_snark.verify( @@ -860,6 +936,147 @@ mod tests { assert!(res.is_ok()); } + #[test] + fn test_ivc_nondet_with_compression() { + // y is a non-deterministic advice representing the fifth root of the input at a step. + #[derive(Clone, Debug)] + struct FifthRootCheckingCircuit { + y: F, + } + + impl FifthRootCheckingCircuit + where + F: PrimeField, + { + fn new(num_steps: usize) -> (F, Vec) { + let mut powers = Vec::new(); + let rng = &mut rand::rngs::OsRng; + let mut seed = F::random(rng); + for _i in 0..num_steps + 1 { + let mut power = seed; + power = power.square(); + power = power.square(); + power *= seed; + + powers.push(Self { y: power }); + + seed = power; + } + + // reverse the powers to get roots + let roots = powers.into_iter().rev().collect::>(); + (roots[0].y, roots[1..].to_vec()) + } + } + + impl StepCircuit for FifthRootCheckingCircuit + where + F: PrimeField, + { + fn synthesize>( + &self, + cs: &mut CS, + z: AllocatedNum, + ) -> Result, SynthesisError> { + let x = z; + + // we allocate a variable and set it to the provided non-derministic advice. + let y = AllocatedNum::alloc(cs.namespace(|| "y"), || Ok(self.y))?; + + // We now check if y = x^{1/5} by checking if y^5 = x + let y_sq = y.square(cs.namespace(|| "y_sq"))?; + let y_quad = y_sq.square(cs.namespace(|| "y_quad"))?; + let y_pow_5 = y_quad.mul(cs.namespace(|| "y_fifth"), &y)?; + + cs.enforce( + || "y^5 = x", + |lc| lc + y_pow_5.get_variable(), + |lc| lc + CS::one(), + |lc| lc + x.get_variable(), + ); + + Ok(y) + } + + fn compute(&self, z: &F) -> F { + // sanity check + let x = *z; + let y_pow_5 = { + let y = self.y; + let y_sq = y.square(); + let y_quad = y_sq.square(); + y_quad * self.y + }; + assert_eq!(x, y_pow_5); + + // return non-deterministic advice + // as the output of the step + self.y + } + } + + let circuit_primary = FifthRootCheckingCircuit { + y: ::Scalar::zero(), + }; + + let circuit_secondary = TrivialTestCircuit { + _p: Default::default(), + }; + + // produce public parameters + let pp = PublicParams::< + G1, + G2, + FifthRootCheckingCircuit<::Scalar>, + TrivialTestCircuit<::Scalar>, + >::setup(circuit_primary, circuit_secondary.clone()); + + let num_steps = 3; + + // produce non-deterministic advice + let (z0_primary, roots) = FifthRootCheckingCircuit::new(num_steps); + let z0_secondary = ::Scalar::zero(); + + // produce a recursive SNARK + let mut recursive_snark: Option< + RecursiveSNARK< + G1, + G2, + FifthRootCheckingCircuit<::Scalar>, + TrivialTestCircuit<::Scalar>, + >, + > = None; + + for circuit_primary in roots.iter().take(num_steps) { + let res = RecursiveSNARK::prove_step( + &pp, + recursive_snark, + circuit_primary.clone(), + circuit_secondary.clone(), + z0_primary, + z0_secondary, + ); + assert!(res.is_ok()); + recursive_snark = Some(res.unwrap()); + } + + assert!(recursive_snark.is_some()); + let recursive_snark = recursive_snark.unwrap(); + + // verify the recursive SNARK + let res = recursive_snark.verify(&pp, num_steps, z0_primary, z0_secondary); + assert!(res.is_ok()); + + // produce a compressed SNARK + let res = CompressedSNARK::<_, _, _, _, S1, S2>::prove(&pp, &recursive_snark); + assert!(res.is_ok()); + let compressed_snark = res.unwrap(); + + // verify the compressed SNARK + let res = compressed_snark.verify(&pp, num_steps, z0_primary, z0_secondary); + assert!(res.is_ok()); + } + #[test] fn test_ivc_base() { // produce public parameters @@ -880,9 +1097,15 @@ mod tests { let num_steps = 1; // produce a recursive SNARK - let res = RecursiveSNARK::prove( + let res = RecursiveSNARK::prove_step( &pp, - num_steps, + None, + TrivialTestCircuit { + _p: Default::default(), + }, + CubicCircuit { + _p: Default::default(), + }, ::Scalar::one(), ::Scalar::zero(), ); diff --git a/src/nifs.rs b/src/nifs.rs index 05153b5..57b5a98 100644 --- a/src/nifs.rs +++ b/src/nifs.rs @@ -12,6 +12,7 @@ use std::marker::PhantomData; /// A SNARK that holds the proof of a step of an incremental computation #[allow(clippy::upper_case_acronyms)] +#[derive(Clone, Debug)] pub struct NIFS { pub(crate) comm_T: CompressedCommitment, _p: PhantomData,