testudo/src/r1csinstance.rs
src/r1csinstance.rsRaw
1use super::dense_mlpoly::DensePolynomial;
2use super::errors::ProofVerifyError;
3use super::math::Math;
4use super::scalar::Scalar;
5use super::sparse_mlpoly::{
6 MultiSparseMatPolynomialAsDense, SparseMatEntry, SparseMatPolyCommitment,
7 SparseMatPolyCommitmentGens, SparseMatPolyEvalProof, SparseMatPolynomial,
8 SparseMatPolynomialSize,
9};
10use super::timer::Timer;
11use super::transcript::{AppendToTranscript, ProofTranscript};
12use merlin::Transcript;
13use rand::rngs::OsRng;
14use serde::{Deserialize, Serialize};
15
16#[derive(Debug)]
17pub struct R1CSInstance {
18 num_cons: usize,
19 num_vars: usize,
20 num_inputs: usize,
21 A: SparseMatPolynomial,
22 B: SparseMatPolynomial,
23 C: SparseMatPolynomial,
24}
25
26pub struct R1CSInstanceSize {
27 size_A: SparseMatPolynomialSize,
28 size_B: SparseMatPolynomialSize,
29 size_C: SparseMatPolynomialSize,
30}
31
32pub struct R1CSCommitmentGens {
33 gens: SparseMatPolyCommitmentGens,
34}
35
36impl R1CSCommitmentGens {
37 pub fn new(size: &R1CSInstanceSize, label: &'static [u8]) -> R1CSCommitmentGens {
38 assert_eq!(size.size_A, size.size_B);
39 assert_eq!(size.size_A, size.size_C);
40 let gens = SparseMatPolyCommitmentGens::new(&size.size_A, 3, label);
41 R1CSCommitmentGens { gens }
42 }
43}
44
45pub struct R1CSCommitment {
46 num_cons: usize,
47 num_vars: usize,
48 num_inputs: usize,
49 comm: SparseMatPolyCommitment,
50}
51
52pub struct R1CSDecommitment {
53 dense: MultiSparseMatPolynomialAsDense,
54}
55
56impl R1CSCommitment {
57 pub fn get_num_cons(&self) -> usize {
58 self.num_cons
59 }
60
61 pub fn get_num_vars(&self) -> usize {
62 self.num_vars
63 }
64
65 pub fn get_num_inputs(&self) -> usize {
66 self.num_inputs
67 }
68}
69
70#[derive(Serialize, Deserialize, Debug)]
71pub struct R1CSInstanceEvals {
72 eval_A_r: Scalar,
73 eval_B_r: Scalar,
74 eval_C_r: Scalar,
75}
76
77impl R1CSInstanceEvals {
78 pub fn get_evaluations(&self) -> (Scalar, Scalar, Scalar) {
79 (self.eval_A_r, self.eval_B_r, self.eval_C_r)
80 }
81}
82
83impl AppendToTranscript for R1CSInstanceEvals {
84 fn append_to_transcript(&self, label: &'static [u8], transcript: &mut Transcript) {
85 transcript.append_message(label, b"R1CSInstanceEvals_begin");
86 transcript.append_scalar(b"Ar_eval", &self.eval_A_r);
87 transcript.append_scalar(b"Br_eval", &self.eval_B_r);
88 transcript.append_scalar(b"Cr_eval", &self.eval_C_r);
89 transcript.append_message(label, b"R1CSInstanceEvals_end");
90 }
91}
92
93impl R1CSInstance {
94 pub fn new(
95 num_cons: usize,
96 num_vars: usize,
97 num_inputs: usize,
98 A: SparseMatPolynomial,
99 B: SparseMatPolynomial,
100 C: SparseMatPolynomial,
101 ) -> Self {
102 R1CSInstance {
103 num_cons,
104 num_vars,
105 num_inputs,
106 A,
107 B,
108 C,
109 }
110 }
111
112 pub fn get_num_vars(&self) -> usize {
113 self.num_vars
114 }
115
116 pub fn get_num_cons(&self) -> usize {
117 self.num_cons
118 }
119
120 pub fn size(&self) -> R1CSInstanceSize {
121 R1CSInstanceSize {
122 size_A: self.A.size(),
123 size_B: self.B.size(),
124 size_C: self.C.size(),
125 }
126 }
127
128 pub fn produce_synthetic_r1cs(
129 num_cons: usize,
130 num_vars: usize,
131 num_inputs: usize,
132 ) -> (R1CSInstance, Vec<Scalar>, Vec<Scalar>) {
133 let mut csprng: OsRng = OsRng;
134
135 // assert num_cons and num_vars are power of 2
136 assert_eq!(num_cons.log2().pow2(), num_cons);
137 assert_eq!(num_vars.log2().pow2(), num_vars);
138
139 // num_inputs + 1 <= num_vars
140 assert!(num_inputs + 1 <= num_vars);
141
142 // z is organized as [vars,1,io]
143 let size_z = num_vars + num_inputs + 1;
144
145 // produce a random satisfying assignment
146 let Z = {
147 let mut Z: Vec<Scalar> = (0..size_z)
148 .map(|_i| Scalar::random(&mut csprng))
149 .collect::<Vec<Scalar>>();
150 Z[num_vars] = Scalar::one(); // set the constant term to 1
151 Z
152 };
153
154 // three sparse matrices
155 let mut A: Vec<SparseMatEntry> = Vec::new();
156 let mut B: Vec<SparseMatEntry> = Vec::new();
157 let mut C: Vec<SparseMatEntry> = Vec::new();
158 let one = Scalar::one();
159 for i in 0..num_cons {
160 let A_idx = i % size_z;
161 let B_idx = (i + 2) % size_z;
162 A.push(SparseMatEntry::new(i, A_idx, one));
163 B.push(SparseMatEntry::new(i, B_idx, one));
164 let AB_val = Z[A_idx] * Z[B_idx];
165
166 let C_idx = (i + 3) % size_z;
167 let C_val = Z[C_idx];
168
169 if C_val == Scalar::zero() {
170 C.push(SparseMatEntry::new(i, num_vars, AB_val));
171 } else {
172 C.push(SparseMatEntry::new(
173 i,
174 C_idx,
175 AB_val * C_val.invert().unwrap(),
176 ));
177 }
178 }
179
180 let num_poly_vars_x = num_cons.log2();
181 let num_poly_vars_y = (2 * num_vars).log2();
182 let poly_A = SparseMatPolynomial::new(num_poly_vars_x, num_poly_vars_y, A);
183 let poly_B = SparseMatPolynomial::new(num_poly_vars_x, num_poly_vars_y, B);
184 let poly_C = SparseMatPolynomial::new(num_poly_vars_x, num_poly_vars_y, C);
185
186 let inst = R1CSInstance::new(num_cons, num_vars, num_inputs, poly_A, poly_B, poly_C);
187
188 assert_eq!(
189 inst.is_sat(&Z[0..num_vars].to_vec(), &Z[num_vars + 1..].to_vec()),
190 true,
191 );
192
193 (inst, Z[0..num_vars].to_vec(), Z[num_vars + 1..].to_vec())
194 }
195
196 pub fn is_sat(&self, vars: &Vec<Scalar>, input: &Vec<Scalar>) -> bool {
197 assert_eq!(vars.len(), self.num_vars);
198 assert_eq!(input.len(), self.num_inputs);
199
200 let z = {
201 let mut z = vars.clone();
202 z.extend(&vec![Scalar::one()]);
203 z.extend(input);
204 z
205 };
206
207 // verify if Az * Bz - Cz = [0...]
208 let Az = self
209 .A
210 .multiply_vec(self.num_cons, self.num_vars + self.num_inputs + 1, &z);
211 let Bz = self
212 .B
213 .multiply_vec(self.num_cons, self.num_vars + self.num_inputs + 1, &z);
214 let Cz = self
215 .C
216 .multiply_vec(self.num_cons, self.num_vars + self.num_inputs + 1, &z);
217
218 assert_eq!(Az.len(), self.num_cons);
219 assert_eq!(Bz.len(), self.num_cons);
220 assert_eq!(Cz.len(), self.num_cons);
221 let res: usize = (0..self.num_cons)
222 .map(|i| if Az[i] * Bz[i] == Cz[i] { 0 } else { 1 })
223 .sum();
224 if res > 0 {
225 false
226 } else {
227 true
228 }
229 }
230
231 pub fn multiply_vec(
232 &self,
233 num_rows: usize,
234 num_cols: usize,
235 z: &Vec<Scalar>,
236 ) -> (DensePolynomial, DensePolynomial, DensePolynomial) {
237 assert_eq!(num_rows, self.num_cons);
238 assert_eq!(z.len(), num_cols);
239 assert!(num_cols > self.num_vars);
240 (
241 DensePolynomial::new(self.A.multiply_vec(num_rows, num_cols, z)),
242 DensePolynomial::new(self.B.multiply_vec(num_rows, num_cols, z)),
243 DensePolynomial::new(self.C.multiply_vec(num_rows, num_cols, z)),
244 )
245 }
246
247 pub fn compute_eval_table_sparse(
248 &self,
249 num_rows: usize,
250 num_cols: usize,
251 evals: &Vec<Scalar>,
252 ) -> (Vec<Scalar>, Vec<Scalar>, Vec<Scalar>) {
253 assert_eq!(num_rows, self.num_cons);
254 assert!(num_cols > self.num_vars);
255
256 let evals_A = self.A.compute_eval_table_sparse(&evals, num_rows, num_cols);
257 let evals_B = self.B.compute_eval_table_sparse(&evals, num_rows, num_cols);
258 let evals_C = self.C.compute_eval_table_sparse(&evals, num_rows, num_cols);
259
260 (evals_A, evals_B, evals_C)
261 }
262
263 pub fn evaluate_with_tables(
264 &self,
265 evals_rx: &Vec<Scalar>,
266 evals_ry: &Vec<Scalar>,
267 ) -> R1CSInstanceEvals {
268 R1CSInstanceEvals {
269 eval_A_r: self.A.evaluate_with_tables(evals_rx, evals_ry),
270 eval_B_r: self.B.evaluate_with_tables(evals_rx, evals_ry),
271 eval_C_r: self.C.evaluate_with_tables(evals_rx, evals_ry),
272 }
273 }
274
275 pub fn commit(&self, gens: &R1CSCommitmentGens) -> (R1CSCommitment, R1CSDecommitment) {
276 assert_eq!(self.A.get_num_nz_entries(), self.B.get_num_nz_entries());
277 assert_eq!(self.A.get_num_nz_entries(), self.C.get_num_nz_entries());
278 let (comm, dense) =
279 SparseMatPolynomial::multi_commit(&vec![&self.A, &self.B, &self.C], &gens.gens);
280 let r1cs_comm = R1CSCommitment {
281 num_cons: self.num_cons,
282 num_vars: self.num_vars,
283 num_inputs: self.num_inputs,
284 comm,
285 };
286
287 let r1cs_decomm = R1CSDecommitment { dense };
288
289 (r1cs_comm, r1cs_decomm)
290 }
291}
292
293#[derive(Debug, Serialize, Deserialize)]
294pub struct R1CSEvalProof {
295 proof: SparseMatPolyEvalProof,
296}
297
298impl R1CSEvalProof {
299 pub fn prove(
300 decomm: &R1CSDecommitment,
301 rx: &Vec<Scalar>, // point at which the polynomial is evaluated
302 ry: &Vec<Scalar>,
303 evals: &R1CSInstanceEvals,
304 gens: &R1CSCommitmentGens,
305 transcript: &mut Transcript,
306 random_tape: &mut Transcript,
307 ) -> R1CSEvalProof {
308 let timer = Timer::new("R1CSEvalProof::prove");
309 let proof = SparseMatPolyEvalProof::prove(
310 &decomm.dense,
311 rx,
312 ry,
313 &vec![evals.eval_A_r, evals.eval_B_r, evals.eval_C_r],
314 &gens.gens,
315 transcript,
316 random_tape,
317 );
318 timer.stop();
319
320 R1CSEvalProof { proof }
321 }
322
323 pub fn verify(
324 &self,
325 comm: &R1CSCommitment,
326 rx: &Vec<Scalar>, // point at which the R1CS matrix polynomials are evaluated
327 ry: &Vec<Scalar>,
328 eval: &R1CSInstanceEvals,
329 gens: &R1CSCommitmentGens,
330 transcript: &mut Transcript,
331 ) -> Result<(), ProofVerifyError> {
332 assert!(self
333 .proof
334 .verify(
335 &comm.comm,
336 rx,
337 ry,
338 &vec![eval.eval_A_r, eval.eval_B_r, eval.eval_C_r],
339 &gens.gens,
340 transcript
341 )
342 .is_ok());
343
344 Ok(())
345 }
346}