sonobe/folding-schemes/src/folding/nova/mod.rs
folding-schemes/src/folding/nova/mod.rsRaw
1/// Implements the scheme described in [Nova](https://eprint.iacr.org/2021/370.pdf) and
2/// [CycleFold](https://eprint.iacr.org/2023/1192.pdf).
3use ark_crypto_primitives::{
4 crh::{poseidon::CRH, CRHScheme},
5 sponge::{poseidon::PoseidonConfig, Absorb},
6};
7use ark_ec::{AffineRepr, CurveGroup, Group};
8use ark_ff::{BigInteger, PrimeField};
9use ark_r1cs_std::{groups::GroupOpsBounds, prelude::CurveVar};
10use ark_std::fmt::Debug;
11use ark_std::{One, Zero};
12use core::marker::PhantomData;
13
14use ark_relations::r1cs::{ConstraintSynthesizer, ConstraintSystem};
15
16use crate::ccs::r1cs::{extract_r1cs, extract_w_x, R1CS};
17use crate::commitment::CommitmentScheme;
18use crate::folding::circuits::nonnative::point_to_nonnative_limbs;
19use crate::frontend::FCircuit;
20use crate::utils::vec::is_zero_vec;
21use crate::Error;
22use crate::FoldingScheme;
23
24pub mod circuits;
25pub mod cyclefold;
26pub mod decider_eth;
27pub mod decider_eth_circuit;
28pub mod nifs;
29pub mod traits;
30
31use circuits::{AugmentedFCircuit, ChallengeGadget, CF2};
32use cyclefold::{CycleFoldChallengeGadget, CycleFoldCircuit};
33use nifs::NIFS;
34use traits::NovaR1CS;
35
36#[cfg(test)]
37use cyclefold::CF_IO_LEN;
38
39#[derive(Debug, Clone, Eq, PartialEq)]
40pub struct CommittedInstance<C: CurveGroup> {
41 pub cmE: C,
42 pub u: C::ScalarField,
43 pub cmW: C,
44 pub x: Vec<C::ScalarField>,
45}
46
47impl<C: CurveGroup> CommittedInstance<C> {
48 pub fn dummy(io_len: usize) -> Self {
49 Self {
50 cmE: C::zero(),
51 u: C::ScalarField::zero(),
52 cmW: C::zero(),
53 x: vec![C::ScalarField::zero(); io_len],
54 }
55 }
56}
57
58impl<C: CurveGroup> CommittedInstance<C>
59where
60 <C as Group>::ScalarField: Absorb,
61 <C as ark_ec::CurveGroup>::BaseField: ark_ff::PrimeField,
62{
63 /// hash implements the committed instance hash compatible with the gadget implemented in
64 /// nova/circuits.rs::CommittedInstanceVar.hash.
65 /// Returns `H(i, z_0, z_i, U_i)`, where `i` can be `i` but also `i+1`, and `U_i` is the
66 /// `CommittedInstance`.
67 pub fn hash(
68 &self,
69 poseidon_config: &PoseidonConfig<C::ScalarField>,
70 i: C::ScalarField,
71 z_0: Vec<C::ScalarField>,
72 z_i: Vec<C::ScalarField>,
73 ) -> Result<C::ScalarField, Error> {
74 let (cmE_x, cmE_y) = point_to_nonnative_limbs::<C>(self.cmE)?;
75 let (cmW_x, cmW_y) = point_to_nonnative_limbs::<C>(self.cmW)?;
76
77 CRH::<C::ScalarField>::evaluate(
78 poseidon_config,
79 vec![
80 vec![i],
81 z_0,
82 z_i,
83 vec![self.u],
84 self.x.clone(),
85 cmE_x,
86 cmE_y,
87 cmW_x,
88 cmW_y,
89 ]
90 .concat(),
91 )
92 .map_err(|e| Error::Other(e.to_string()))
93 }
94}
95
96#[derive(Debug, Clone, Eq, PartialEq)]
97pub struct Witness<C: CurveGroup> {
98 pub E: Vec<C::ScalarField>,
99 pub rE: C::ScalarField,
100 pub W: Vec<C::ScalarField>,
101 pub rW: C::ScalarField,
102}
103
104impl<C: CurveGroup> Witness<C>
105where
106 <C as Group>::ScalarField: Absorb,
107{
108 pub fn new(w: Vec<C::ScalarField>, e_len: usize) -> Self {
109 // note: at the current version, we don't use the blinding factors and we set them to 0
110 // always.
111 Self {
112 E: vec![C::ScalarField::zero(); e_len],
113 rE: C::ScalarField::zero(),
114 W: w,
115 rW: C::ScalarField::zero(),
116 }
117 }
118 pub fn commit<CS: CommitmentScheme<C>>(
119 &self,
120 params: &CS::ProverParams,
121 x: Vec<C::ScalarField>,
122 ) -> Result<CommittedInstance<C>, Error> {
123 let mut cmE = C::zero();
124 if !is_zero_vec::<C::ScalarField>(&self.E) {
125 cmE = CS::commit(params, &self.E, &self.rE)?;
126 }
127 let cmW = CS::commit(params, &self.W, &self.rW)?;
128 Ok(CommittedInstance {
129 cmE,
130 u: C::ScalarField::one(),
131 cmW,
132 x,
133 })
134 }
135}
136
137#[derive(Debug, Clone)]
138pub struct ProverParams<C1, C2, CS1, CS2>
139where
140 C1: CurveGroup,
141 C2: CurveGroup,
142 CS1: CommitmentScheme<C1>,
143 CS2: CommitmentScheme<C2>,
144{
145 pub poseidon_config: PoseidonConfig<C1::ScalarField>,
146 pub cs_params: CS1::ProverParams,
147 pub cf_cs_params: CS2::ProverParams,
148}
149
150#[derive(Debug, Clone)]
151pub struct VerifierParams<C1: CurveGroup, C2: CurveGroup> {
152 pub poseidon_config: PoseidonConfig<C1::ScalarField>,
153 pub r1cs: R1CS<C1::ScalarField>,
154 pub cf_r1cs: R1CS<C2::ScalarField>,
155}
156
157/// Implements Nova+CycleFold's IVC, described in [Nova](https://eprint.iacr.org/2021/370.pdf) and
158/// [CycleFold](https://eprint.iacr.org/2023/1192.pdf), following the FoldingScheme trait
159#[derive(Clone, Debug)]
160pub struct Nova<C1, GC1, C2, GC2, FC, CS1, CS2>
161where
162 C1: CurveGroup,
163 GC1: CurveVar<C1, CF2<C1>>,
164 C2: CurveGroup,
165 GC2: CurveVar<C2, CF2<C2>>,
166 FC: FCircuit<C1::ScalarField>,
167 CS1: CommitmentScheme<C1>,
168 CS2: CommitmentScheme<C2>,
169{
170 _gc1: PhantomData<GC1>,
171 _c2: PhantomData<C2>,
172 _gc2: PhantomData<GC2>,
173 /// R1CS of the Augmented Function circuit
174 pub r1cs: R1CS<C1::ScalarField>,
175 /// R1CS of the CycleFold circuit
176 pub cf_r1cs: R1CS<C2::ScalarField>,
177 pub poseidon_config: PoseidonConfig<C1::ScalarField>,
178 /// CommitmentScheme::ProverParams over C1
179 pub cs_params: CS1::ProverParams,
180 /// CycleFold CommitmentScheme::ProverParams, over C2
181 pub cf_cs_params: CS2::ProverParams,
182 /// F circuit, the circuit that is being folded
183 pub F: FC,
184 pub i: C1::ScalarField,
185 /// initial state
186 pub z_0: Vec<C1::ScalarField>,
187 /// current i-th state
188 pub z_i: Vec<C1::ScalarField>,
189 /// Nova instances
190 pub w_i: Witness<C1>,
191 pub u_i: CommittedInstance<C1>,
192 pub W_i: Witness<C1>,
193 pub U_i: CommittedInstance<C1>,
194
195 /// CycleFold running instance
196 pub cf_W_i: Witness<C2>,
197 pub cf_U_i: CommittedInstance<C2>,
198}
199
200impl<C1, GC1, C2, GC2, FC, CS1, CS2> FoldingScheme<C1, C2, FC>
201 for Nova<C1, GC1, C2, GC2, FC, CS1, CS2>
202where
203 C1: CurveGroup,
204 GC1: CurveVar<C1, CF2<C1>>,
205 C2: CurveGroup,
206 GC2: CurveVar<C2, CF2<C2>>,
207 FC: FCircuit<C1::ScalarField>,
208 CS1: CommitmentScheme<C1>,
209 CS2: CommitmentScheme<C2>,
210 <C1 as CurveGroup>::BaseField: PrimeField,
211 <C2 as CurveGroup>::BaseField: PrimeField,
212 <C1 as Group>::ScalarField: Absorb,
213 <C2 as Group>::ScalarField: Absorb,
214 C1: CurveGroup<BaseField = C2::ScalarField, ScalarField = C2::BaseField>,
215 for<'a> &'a GC1: GroupOpsBounds<'a, C1, GC1>,
216 for<'a> &'a GC2: GroupOpsBounds<'a, C2, GC2>,
217{
218 type PreprocessorParam = (Self::ProverParam, FC);
219 type ProverParam = ProverParams<C1, C2, CS1, CS2>;
220 type VerifierParam = VerifierParams<C1, C2>;
221 type CommittedInstanceWithWitness = (CommittedInstance<C1>, Witness<C1>);
222 type CFCommittedInstanceWithWitness = (CommittedInstance<C2>, Witness<C2>);
223
224 fn preprocess(
225 prep_param: &Self::PreprocessorParam,
226 ) -> Result<(Self::ProverParam, Self::VerifierParam), Error> {
227 let (prover_params, F_circuit) = prep_param;
228
229 let (r1cs, cf_r1cs) =
230 get_r1cs::<C1, GC1, C2, GC2, FC>(&prover_params.poseidon_config, F_circuit.clone())?;
231
232 let verifier_params = VerifierParams::<C1, C2> {
233 poseidon_config: prover_params.poseidon_config.clone(),
234 r1cs,
235 cf_r1cs,
236 };
237 Ok((prover_params.clone(), verifier_params))
238 }
239
240 /// Initializes the Nova+CycleFold's IVC for the given parameters and initial state `z_0`.
241 fn init(pp: &Self::ProverParam, F: FC, z_0: Vec<C1::ScalarField>) -> Result<Self, Error> {
242 // prepare the circuit to obtain its R1CS
243 let cs = ConstraintSystem::<C1::ScalarField>::new_ref();
244 let cs2 = ConstraintSystem::<C1::BaseField>::new_ref();
245
246 let augmented_F_circuit =
247 AugmentedFCircuit::<C1, C2, GC2, FC>::empty(&pp.poseidon_config, F.clone());
248 let cf_circuit = CycleFoldCircuit::<C1, GC1>::empty();
249
250 augmented_F_circuit.generate_constraints(cs.clone())?;
251 cs.finalize();
252 let cs = cs.into_inner().ok_or(Error::NoInnerConstraintSystem)?;
253 let r1cs = extract_r1cs::<C1::ScalarField>(&cs);
254
255 cf_circuit.generate_constraints(cs2.clone())?;
256 cs2.finalize();
257 let cs2 = cs2.into_inner().ok_or(Error::NoInnerConstraintSystem)?;
258 let cf_r1cs = extract_r1cs::<C1::BaseField>(&cs2);
259
260 // setup the dummy instances
261 let (w_dummy, u_dummy) = r1cs.dummy_instance();
262 let (cf_w_dummy, cf_u_dummy) = cf_r1cs.dummy_instance();
263
264 // W_dummy=W_0 is a 'dummy witness', all zeroes, but with the size corresponding to the
265 // R1CS that we're working with.
266 Ok(Self {
267 _gc1: PhantomData,
268 _c2: PhantomData,
269 _gc2: PhantomData,
270 r1cs,
271 cf_r1cs,
272 poseidon_config: pp.poseidon_config.clone(),
273 cs_params: pp.cs_params.clone(),
274 cf_cs_params: pp.cf_cs_params.clone(),
275 F,
276 i: C1::ScalarField::zero(),
277 z_0: z_0.clone(),
278 z_i: z_0,
279 w_i: w_dummy.clone(),
280 u_i: u_dummy.clone(),
281 W_i: w_dummy,
282 U_i: u_dummy,
283 // cyclefold running instance
284 cf_W_i: cf_w_dummy.clone(),
285 cf_U_i: cf_u_dummy.clone(),
286 })
287 }
288
289 /// Implements IVC.P of Nova+CycleFold
290 fn prove_step(&mut self) -> Result<(), Error> {
291 let augmented_F_circuit: AugmentedFCircuit<C1, C2, GC2, FC>;
292 let cfW_circuit: CycleFoldCircuit<C1, GC1>;
293 let cfE_circuit: CycleFoldCircuit<C1, GC1>;
294
295 if self.i > C1::ScalarField::from_le_bytes_mod_order(&std::usize::MAX.to_le_bytes()) {
296 return Err(Error::MaxStep);
297 }
298 let mut i_bytes: [u8; 8] = [0; 8];
299 i_bytes.copy_from_slice(&self.i.into_bigint().to_bytes_le()[..8]);
300 let i_usize: usize = usize::from_le_bytes(i_bytes);
301
302 let z_i1 = self.F.step_native(i_usize, self.z_i.clone())?;
303
304 // compute T and cmT for AugmentedFCircuit
305 let (T, cmT) = self.compute_cmT()?;
306
307 // r_bits is the r used to the RLC of the F' instances
308 let r_bits = ChallengeGadget::<C1>::get_challenge_native(
309 &self.poseidon_config,
310 self.U_i.clone(),
311 self.u_i.clone(),
312 cmT,
313 )?;
314 let r_Fr = C1::ScalarField::from_bigint(BigInteger::from_bits_le(&r_bits))
315 .ok_or(Error::OutOfBounds)?;
316
317 // fold Nova instances
318 let (W_i1, U_i1): (Witness<C1>, CommittedInstance<C1>) = NIFS::<C1, CS1>::fold_instances(
319 r_Fr, &self.W_i, &self.U_i, &self.w_i, &self.u_i, &T, cmT,
320 )?;
321
322 // folded instance output (public input, x)
323 // u_{i+1}.x = H(i+1, z_0, z_{i+1}, U_{i+1})
324 let u_i1_x = U_i1.hash(
325 &self.poseidon_config,
326 self.i + C1::ScalarField::one(),
327 self.z_0.clone(),
328 z_i1.clone(),
329 )?;
330
331 if self.i == C1::ScalarField::zero() {
332 // base case
333 augmented_F_circuit = AugmentedFCircuit::<C1, C2, GC2, FC> {
334 _gc2: PhantomData,
335 poseidon_config: self.poseidon_config.clone(),
336 i: Some(C1::ScalarField::zero()), // = i=0
337 i_usize: Some(0),
338 z_0: Some(self.z_0.clone()), // = z_i
339 z_i: Some(self.z_i.clone()),
340 u_i: Some(self.u_i.clone()), // = dummy
341 U_i: Some(self.U_i.clone()), // = dummy
342 U_i1: Some(U_i1.clone()),
343 cmT: Some(cmT),
344 F: self.F.clone(),
345 x: Some(u_i1_x),
346 cf1_u_i: None,
347 cf2_u_i: None,
348 cf_U_i: None,
349 cf1_U_i1: None,
350 cf_U_i1: None,
351 cf1_cmT: None,
352 cf2_cmT: None,
353 cf1_r_nonnat: None,
354 cf2_r_nonnat: None,
355 };
356
357 #[cfg(test)]
358 NIFS::<C1, CS1>::verify_folded_instance(r_Fr, &self.U_i, &self.u_i, &U_i1, &cmT)?;
359 } else {
360 // CycleFold part:
361 // get the vector used as public inputs 'x' in the CycleFold circuit
362 // cyclefold circuit for cmW
363 let cfW_u_i_x = [
364 get_cm_coordinates(&self.U_i.cmW),
365 get_cm_coordinates(&self.u_i.cmW),
366 get_cm_coordinates(&U_i1.cmW),
367 ]
368 .concat();
369 // cyclefold circuit for cmE
370 let cfE_u_i_x = [
371 get_cm_coordinates(&self.U_i.cmE),
372 get_cm_coordinates(&self.u_i.cmE),
373 get_cm_coordinates(&U_i1.cmE),
374 ]
375 .concat();
376
377 cfW_circuit = CycleFoldCircuit::<C1, GC1> {
378 _gc: PhantomData,
379 r_bits: Some(r_bits.clone()),
380 p1: Some(self.U_i.clone().cmW),
381 p2: Some(self.u_i.clone().cmW),
382 p3: Some(U_i1.clone().cmW),
383 x: Some(cfW_u_i_x.clone()),
384 };
385 cfE_circuit = CycleFoldCircuit::<C1, GC1> {
386 _gc: PhantomData,
387 r_bits: Some(r_bits.clone()),
388 p1: Some(self.U_i.clone().cmE),
389 p2: Some(cmT),
390 p3: Some(U_i1.clone().cmE),
391 x: Some(cfE_u_i_x.clone()),
392 };
393
394 // fold self.cf_U_i + cfW_U -> folded running with cfW
395 let (_cfW_w_i, cfW_u_i, cfW_W_i1, cfW_U_i1, cfW_cmT, cfW_r1_Fq) = self
396 .fold_cyclefold_circuit(
397 self.cf_W_i.clone(), // CycleFold running instance witness
398 self.cf_U_i.clone(), // CycleFold running instance
399 cfW_u_i_x,
400 cfW_circuit,
401 )?;
402 // fold [the output from folding self.cf_U_i + cfW_U] + cfE_U = folded_running_with_cfW + cfE
403 let (_cfE_w_i, cfE_u_i, cf_W_i1, cf_U_i1, cf_cmT, cf_r2_Fq) =
404 self.fold_cyclefold_circuit(cfW_W_i1, cfW_U_i1.clone(), cfE_u_i_x, cfE_circuit)?;
405
406 augmented_F_circuit = AugmentedFCircuit::<C1, C2, GC2, FC> {
407 _gc2: PhantomData,
408 poseidon_config: self.poseidon_config.clone(),
409 i: Some(self.i),
410 i_usize: Some(i_usize),
411 z_0: Some(self.z_0.clone()),
412 z_i: Some(self.z_i.clone()),
413 u_i: Some(self.u_i.clone()),
414 U_i: Some(self.U_i.clone()),
415 U_i1: Some(U_i1.clone()),
416 cmT: Some(cmT),
417 F: self.F.clone(),
418 x: Some(u_i1_x),
419 // cyclefold values
420 cf1_u_i: Some(cfW_u_i.clone()),
421 cf2_u_i: Some(cfE_u_i.clone()),
422 cf_U_i: Some(self.cf_U_i.clone()),
423 cf1_U_i1: Some(cfW_U_i1.clone()),
424 cf_U_i1: Some(cf_U_i1.clone()),
425 cf1_cmT: Some(cfW_cmT),
426 cf2_cmT: Some(cf_cmT),
427 cf1_r_nonnat: Some(cfW_r1_Fq),
428 cf2_r_nonnat: Some(cf_r2_Fq),
429 };
430
431 self.cf_W_i = cf_W_i1.clone();
432 self.cf_U_i = cf_U_i1.clone();
433
434 #[cfg(test)]
435 {
436 self.cf_r1cs.check_instance_relation(&_cfW_w_i, &cfW_u_i)?;
437 self.cf_r1cs.check_instance_relation(&_cfE_w_i, &cfE_u_i)?;
438 self.cf_r1cs
439 .check_relaxed_instance_relation(&self.cf_W_i, &self.cf_U_i)?;
440 }
441 }
442
443 let cs = ConstraintSystem::<C1::ScalarField>::new_ref();
444
445 augmented_F_circuit.generate_constraints(cs.clone())?;
446
447 #[cfg(test)]
448 assert!(cs.is_satisfied().unwrap());
449
450 let cs = cs.into_inner().ok_or(Error::NoInnerConstraintSystem)?;
451 let (w_i1, x_i1) = extract_w_x::<C1::ScalarField>(&cs);
452 if x_i1[0] != u_i1_x {
453 return Err(Error::NotEqual);
454 }
455
456 #[cfg(test)]
457 if x_i1.len() != 1 {
458 return Err(Error::NotExpectedLength(x_i1.len(), 1));
459 }
460
461 // set values for next iteration
462 self.i += C1::ScalarField::one();
463 self.z_i = z_i1.clone();
464 self.w_i = Witness::<C1>::new(w_i1, self.r1cs.A.n_rows);
465 self.u_i = self.w_i.commit::<CS1>(&self.cs_params, vec![u_i1_x])?;
466 self.W_i = W_i1.clone();
467 self.U_i = U_i1.clone();
468
469 #[cfg(test)]
470 {
471 self.r1cs.check_instance_relation(&self.w_i, &self.u_i)?;
472 self.r1cs
473 .check_relaxed_instance_relation(&self.W_i, &self.U_i)?;
474 }
475
476 Ok(())
477 }
478
479 fn state(&self) -> Vec<C1::ScalarField> {
480 self.z_i.clone()
481 }
482 fn instances(
483 &self,
484 ) -> (
485 Self::CommittedInstanceWithWitness,
486 Self::CommittedInstanceWithWitness,
487 Self::CFCommittedInstanceWithWitness,
488 ) {
489 (
490 (self.U_i.clone(), self.W_i.clone()),
491 (self.u_i.clone(), self.w_i.clone()),
492 (self.cf_U_i.clone(), self.cf_W_i.clone()),
493 )
494 }
495
496 /// Implements IVC.V of Nova+CycleFold
497 fn verify(
498 vp: Self::VerifierParam,
499 z_0: Vec<C1::ScalarField>, // initial state
500 z_i: Vec<C1::ScalarField>, // last state
501 num_steps: C1::ScalarField,
502 running_instance: Self::CommittedInstanceWithWitness,
503 incoming_instance: Self::CommittedInstanceWithWitness,
504 cyclefold_instance: Self::CFCommittedInstanceWithWitness,
505 ) -> Result<(), Error> {
506 let (U_i, W_i) = running_instance;
507 let (u_i, w_i) = incoming_instance;
508 let (cf_U_i, cf_W_i) = cyclefold_instance;
509
510 if u_i.x.len() != 1 || U_i.x.len() != 1 {
511 return Err(Error::IVCVerificationFail);
512 }
513
514 // check that u_i's output points to the running instance
515 // u_i.X == H(i, z_0, z_i, U_i)
516 let expected_u_i_x = U_i.hash(&vp.poseidon_config, num_steps, z_0, z_i.clone())?;
517 if expected_u_i_x != u_i.x[0] {
518 return Err(Error::IVCVerificationFail);
519 }
520
521 // check u_i.cmE==0, u_i.u==1 (=u_i is a un-relaxed instance)
522 if !u_i.cmE.is_zero() || !u_i.u.is_one() {
523 return Err(Error::IVCVerificationFail);
524 }
525
526 // check R1CS satisfiability
527 vp.r1cs.check_instance_relation(&w_i, &u_i)?;
528 // check RelaxedR1CS satisfiability
529 vp.r1cs.check_relaxed_instance_relation(&W_i, &U_i)?;
530
531 // check CycleFold RelaxedR1CS satisfiability
532 vp.cf_r1cs
533 .check_relaxed_instance_relation(&cf_W_i, &cf_U_i)?;
534
535 Ok(())
536 }
537}
538
539impl<C1, GC1, C2, GC2, FC, CS1, CS2> Nova<C1, GC1, C2, GC2, FC, CS1, CS2>
540where
541 C1: CurveGroup,
542 GC1: CurveVar<C1, CF2<C1>>,
543 C2: CurveGroup,
544 GC2: CurveVar<C2, CF2<C2>>,
545 FC: FCircuit<C1::ScalarField>,
546 CS1: CommitmentScheme<C1>,
547 CS2: CommitmentScheme<C2>,
548 <C2 as CurveGroup>::BaseField: PrimeField,
549 <C1 as Group>::ScalarField: Absorb,
550 <C2 as Group>::ScalarField: Absorb,
551 C1: CurveGroup<BaseField = C2::ScalarField, ScalarField = C2::BaseField>,
552{
553 // computes T and cmT for the AugmentedFCircuit
554 fn compute_cmT(&self) -> Result<(Vec<C1::ScalarField>, C1), Error> {
555 NIFS::<C1, CS1>::compute_cmT(
556 &self.cs_params,
557 &self.r1cs,
558 &self.w_i,
559 &self.u_i,
560 &self.W_i,
561 &self.U_i,
562 )
563 }
564 // computes T* and cmT* for the CycleFoldCircuit
565 fn compute_cf_cmT(
566 &self,
567 cf_w_i: &Witness<C2>,
568 cf_u_i: &CommittedInstance<C2>,
569 cf_W_i: &Witness<C2>,
570 cf_U_i: &CommittedInstance<C2>,
571 ) -> Result<(Vec<C2::ScalarField>, C2), Error> {
572 NIFS::<C2, CS2>::compute_cyclefold_cmT(
573 &self.cf_cs_params,
574 &self.cf_r1cs,
575 cf_w_i,
576 cf_u_i,
577 cf_W_i,
578 cf_U_i,
579 )
580 }
581}
582
583impl<C1, GC1, C2, GC2, FC, CS1, CS2> Nova<C1, GC1, C2, GC2, FC, CS1, CS2>
584where
585 C1: CurveGroup,
586 GC1: CurveVar<C1, CF2<C1>>,
587 C2: CurveGroup,
588 GC2: CurveVar<C2, CF2<C2>>,
589 FC: FCircuit<C1::ScalarField>,
590 CS1: CommitmentScheme<C1>,
591 CS2: CommitmentScheme<C2>,
592 <C1 as CurveGroup>::BaseField: PrimeField,
593 <C2 as CurveGroup>::BaseField: PrimeField,
594 <C1 as Group>::ScalarField: Absorb,
595 <C2 as Group>::ScalarField: Absorb,
596 C1: CurveGroup<BaseField = C2::ScalarField, ScalarField = C2::BaseField>,
597 for<'a> &'a GC1: GroupOpsBounds<'a, C1, GC1>,
598 for<'a> &'a GC2: GroupOpsBounds<'a, C2, GC2>,
599{
600 // folds the given cyclefold circuit and its instances
601 #[allow(clippy::type_complexity)]
602 fn fold_cyclefold_circuit(
603 &self,
604 cf_W_i: Witness<C2>, // witness of the running instance
605 cf_U_i: CommittedInstance<C2>, // running instance
606 cf_u_i_x: Vec<C2::ScalarField>,
607 cf_circuit: CycleFoldCircuit<C1, GC1>,
608 ) -> Result<
609 (
610 Witness<C2>,
611 CommittedInstance<C2>, // u_i
612 Witness<C2>, // W_i1
613 CommittedInstance<C2>, // U_i1
614 C2, // cmT
615 C2::ScalarField, // r_Fq
616 ),
617 Error,
618 > {
619 let cs2 = ConstraintSystem::<C1::BaseField>::new_ref();
620 cf_circuit.generate_constraints(cs2.clone())?;
621
622 let cs2 = cs2.into_inner().ok_or(Error::NoInnerConstraintSystem)?;
623 let (cf_w_i, cf_x_i) = extract_w_x::<C1::BaseField>(&cs2);
624 if cf_x_i != cf_u_i_x {
625 return Err(Error::NotEqual);
626 }
627
628 #[cfg(test)]
629 if cf_x_i.len() != CF_IO_LEN {
630 return Err(Error::NotExpectedLength(cf_x_i.len(), CF_IO_LEN));
631 }
632
633 // fold cyclefold instances
634 let cf_w_i = Witness::<C2>::new(cf_w_i.clone(), self.cf_r1cs.A.n_rows);
635 let cf_u_i: CommittedInstance<C2> =
636 cf_w_i.commit::<CS2>(&self.cf_cs_params, cf_x_i.clone())?;
637
638 // compute T* and cmT* for CycleFoldCircuit
639 let (cf_T, cf_cmT) = self.compute_cf_cmT(&cf_w_i, &cf_u_i, &cf_W_i, &cf_U_i)?;
640
641 let cf_r_bits = CycleFoldChallengeGadget::<C2, GC2>::get_challenge_native(
642 &self.poseidon_config,
643 cf_U_i.clone(),
644 cf_u_i.clone(),
645 cf_cmT,
646 )?;
647 let cf_r_Fq = C1::BaseField::from_bigint(BigInteger::from_bits_le(&cf_r_bits))
648 .ok_or(Error::OutOfBounds)?;
649
650 let (cf_W_i1, cf_U_i1) = NIFS::<C2, CS2>::fold_instances(
651 cf_r_Fq, &cf_W_i, &cf_U_i, &cf_w_i, &cf_u_i, &cf_T, cf_cmT,
652 )?;
653 Ok((cf_w_i, cf_u_i, cf_W_i1, cf_U_i1, cf_cmT, cf_r_Fq))
654 }
655}
656
657/// helper method to get the r1cs from the ConstraintSynthesizer
658pub fn get_r1cs_from_cs<F: PrimeField>(
659 circuit: impl ConstraintSynthesizer<F>,
660) -> Result<R1CS<F>, Error> {
661 let cs = ConstraintSystem::<F>::new_ref();
662 circuit.generate_constraints(cs.clone())?;
663 cs.finalize();
664 let cs = cs.into_inner().ok_or(Error::NoInnerConstraintSystem)?;
665 let r1cs = extract_r1cs::<F>(&cs);
666 Ok(r1cs)
667}
668
669/// helper method to get the R1CS for both the AugmentedFCircuit and the CycleFold circuit
670#[allow(clippy::type_complexity)]
671pub fn get_r1cs<C1, GC1, C2, GC2, FC>(
672 poseidon_config: &PoseidonConfig<C1::ScalarField>,
673 F_circuit: FC,
674) -> Result<(R1CS<C1::ScalarField>, R1CS<C2::ScalarField>), Error>
675where
676 C1: CurveGroup,
677 GC1: CurveVar<C1, CF2<C1>>,
678 C2: CurveGroup,
679 GC2: CurveVar<C2, CF2<C2>>,
680 FC: FCircuit<C1::ScalarField>,
681 <C1 as CurveGroup>::BaseField: PrimeField,
682 <C2 as CurveGroup>::BaseField: PrimeField,
683 <C1 as Group>::ScalarField: Absorb,
684 <C2 as Group>::ScalarField: Absorb,
685 C1: CurveGroup<BaseField = C2::ScalarField, ScalarField = C2::BaseField>,
686 for<'a> &'a GC1: GroupOpsBounds<'a, C1, GC1>,
687 for<'a> &'a GC2: GroupOpsBounds<'a, C2, GC2>,
688{
689 let augmented_F_circuit =
690 AugmentedFCircuit::<C1, C2, GC2, FC>::empty(poseidon_config, F_circuit);
691 let cf_circuit = CycleFoldCircuit::<C1, GC1>::empty();
692 let r1cs = get_r1cs_from_cs::<C1::ScalarField>(augmented_F_circuit)?;
693 let cf_r1cs = get_r1cs_from_cs::<C2::ScalarField>(cf_circuit)?;
694 Ok((r1cs, cf_r1cs))
695}
696
697/// helper method to get the pedersen params length for both the AugmentedFCircuit and the
698/// CycleFold circuit
699pub fn get_cs_params_len<C1, GC1, C2, GC2, FC>(
700 poseidon_config: &PoseidonConfig<C1::ScalarField>,
701 F_circuit: FC,
702) -> Result<(usize, usize), Error>
703where
704 C1: CurveGroup,
705 GC1: CurveVar<C1, CF2<C1>>,
706 C2: CurveGroup,
707 GC2: CurveVar<C2, CF2<C2>>,
708 FC: FCircuit<C1::ScalarField>,
709 <C1 as CurveGroup>::BaseField: PrimeField,
710 <C2 as CurveGroup>::BaseField: PrimeField,
711 <C1 as Group>::ScalarField: Absorb,
712 <C2 as Group>::ScalarField: Absorb,
713 C1: CurveGroup<BaseField = C2::ScalarField, ScalarField = C2::BaseField>,
714 for<'a> &'a GC1: GroupOpsBounds<'a, C1, GC1>,
715 for<'a> &'a GC2: GroupOpsBounds<'a, C2, GC2>,
716{
717 let (r1cs, cf_r1cs) = get_r1cs::<C1, GC1, C2, GC2, FC>(poseidon_config, F_circuit)?;
718 Ok((r1cs.A.n_rows, cf_r1cs.A.n_rows))
719}
720
721/// returns the coordinates of a commitment point
722pub(crate) fn get_cm_coordinates<C: CurveGroup>(cm: &C) -> Vec<C::BaseField> {
723 let zero = (&C::BaseField::zero(), &C::BaseField::one());
724 let cm = cm.into_affine();
725 let (cm_x, cm_y) = cm.xy().unwrap_or(zero);
726 vec![*cm_x, *cm_y]
727}
728
729#[cfg(test)]
730pub mod tests {
731 use super::*;
732 use crate::commitment::kzg::{ProverKey as KZGProverKey, KZG};
733 use ark_bn254::{constraints::GVar, Bn254, Fr, G1Projective as Projective};
734 use ark_grumpkin::{constraints::GVar as GVar2, Projective as Projective2};
735 use ark_poly_commit::kzg10::VerifierKey as KZGVerifierKey;
736
737 use crate::commitment::pedersen::Pedersen;
738 use crate::frontend::tests::CubicFCircuit;
739 use crate::transcript::poseidon::poseidon_test_config;
740
741 /// This test tests the Nova+CycleFold IVC, and by consequence it is also testing the
742 /// AugmentedFCircuit
743 #[test]
744 fn test_ivc() {
745 let mut rng = ark_std::test_rng();
746 let poseidon_config = poseidon_test_config::<Fr>();
747
748 let F_circuit = CubicFCircuit::<Fr>::new(());
749
750 let (cs_len, cf_cs_len) =
751 get_cs_params_len::<Projective, GVar, Projective2, GVar2, CubicFCircuit<Fr>>(
752 &poseidon_config,
753 F_circuit,
754 )
755 .unwrap();
756 let (kzg_pk, _): (KZGProverKey<Projective>, KZGVerifierKey<Bn254>) =
757 KZG::<Bn254>::setup(&mut rng, cs_len).unwrap();
758 let (pedersen_params, _) = Pedersen::<Projective>::setup(&mut rng, cs_len).unwrap();
759 let (cf_pedersen_params, _) = Pedersen::<Projective2>::setup(&mut rng, cf_cs_len).unwrap();
760
761 // run the test using Pedersen commitments on both sides of the curve cycle
762 test_ivc_opt::<Pedersen<Projective>, Pedersen<Projective2>>(
763 poseidon_config.clone(),
764 pedersen_params,
765 cf_pedersen_params.clone(),
766 F_circuit,
767 );
768 // run the test using KZG for the commitments on the main curve, and Pedersen for the
769 // commitments on the secondary curve
770 test_ivc_opt::<KZG<Bn254>, Pedersen<Projective2>>(
771 poseidon_config,
772 kzg_pk,
773 cf_pedersen_params,
774 F_circuit,
775 );
776 }
777
778 // test_ivc allowing to choose the CommitmentSchemes
779 fn test_ivc_opt<CS1: CommitmentScheme<Projective>, CS2: CommitmentScheme<Projective2>>(
780 poseidon_config: PoseidonConfig<Fr>,
781 cs_params: CS1::ProverParams,
782 cf_cs_params: CS2::ProverParams,
783 F_circuit: CubicFCircuit<Fr>,
784 ) {
785 type NOVA<CS1, CS2> =
786 Nova<Projective, GVar, Projective2, GVar2, CubicFCircuit<Fr>, CS1, CS2>;
787
788 let prover_params = ProverParams::<Projective, Projective2, CS1, CS2> {
789 poseidon_config: poseidon_config.clone(),
790 cs_params,
791 cf_cs_params,
792 };
793
794 let z_0 = vec![Fr::from(3_u32)];
795 let mut nova = NOVA::init(&prover_params, F_circuit, z_0.clone()).unwrap();
796
797 let num_steps: usize = 3;
798 for _ in 0..num_steps {
799 nova.prove_step().unwrap();
800 }
801 assert_eq!(Fr::from(num_steps as u32), nova.i);
802
803 let verifier_params = VerifierParams::<Projective, Projective2> {
804 poseidon_config,
805 r1cs: nova.clone().r1cs,
806 cf_r1cs: nova.clone().cf_r1cs,
807 };
808 let (running_instance, incoming_instance, cyclefold_instance) = nova.instances();
809 NOVA::<CS1, CS2>::verify(
810 verifier_params,
811 z_0,
812 nova.z_i,
813 nova.i,
814 running_instance,
815 incoming_instance,
816 cyclefold_instance,
817 )
818 .unwrap();
819 }
820}