279 lines
12 KiB
Rust
279 lines
12 KiB
Rust
extern crate pairing;
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extern crate rand;
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use super::*;
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use rand::{thread_rng, Rng};
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use cl::{KeyPair, Signature, PublicParams, setup, BlindKeyPair, ProofState, SignatureProof, BlindPublicKey};
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use ped92::{CSParams, Commitment, CSMultiParams};
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use pairing::{Engine, CurveProjective};
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use ff::PrimeField;
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use util::hash_g2_to_fr;
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use commit_scheme::commit;
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use wallet::Wallet;
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use ccs08::{RPPublicParams, RangeProof};
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#[derive(Clone)]
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pub struct Proof<E: Engine> {
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pub sig: Signature<E>,
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pub sigProof: SignatureProof<E>,
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pub D: E::G1,
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pub z: Vec<E::Fr>,
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pub rpBC: RangeProof<E>,
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pub rpBM: RangeProof<E>,
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}
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#[derive(Clone)]
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pub struct NIZKPublicParams<E: Engine> {
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pub mpk: PublicParams<E>,
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pub keypair: BlindKeyPair<E>,
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pub comParams: CSMultiParams<E>,
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pub rpParamsBC: RPPublicParams<E>,
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pub rpParamsBM: RPPublicParams<E>,
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}
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impl<E: Engine> NIZKPublicParams<E> {
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pub fn setup<R: Rng>(rng: &mut R, messageLength: usize) -> Self {
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let mpk = setup(rng);
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let keypair = BlindKeyPair::<E>::generate(rng, &mpk, messageLength);
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let comParams = keypair.generate_cs_multi_params(&mpk);
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let rpParamsBC = RPPublicParams::setup(rng, 0, std::i16::MAX as i32, comParams.clone());
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let rpParamsBM = RPPublicParams::setup(rng, 0, std::i16::MAX as i32, comParams.clone());
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NIZKPublicParams{mpk, keypair, comParams, rpParamsBC, rpParamsBM}
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}
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pub fn prove<R: Rng>(&self, rng: &mut R, r: E::Fr, oldWallet: Wallet<E>, newWallet: Wallet<E>,
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newWalletCom: Commitment<E>, rPrime: E::Fr, paymentToken: &Signature<E>) -> Proof<E> {
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//Commitment phase
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//commit commitment
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let mut D = E::G1::zero();
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let mut t = Vec::<E::Fr>::with_capacity(self.comParams.pub_bases.len());
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for g in self.comParams.pub_bases.clone() {
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let ti = E::Fr::rand(rng);
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t.push(ti);
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let mut gt = g.clone();
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gt.mul_assign(ti.into_repr());
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D.add_assign(>);
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}
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//commit signature
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let fr1 = E::Fr::rand(rng);
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let proofState = self.keypair.prove_commitment(rng, &self.mpk, &paymentToken, Some(vec!(t[1], fr1, t[3].clone(), t[4].clone())), None);
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//commit range proof
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let rpStateBC = self.rpParamsBC.prove_commitment(rng, newWallet.bc.clone(), newWalletCom.clone(), 3, Some(t[1..].to_vec()), Some(t[0].clone()));
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let rpStateBM = self.rpParamsBM.prove_commitment(rng, newWallet.bm.clone(), newWalletCom.clone(), 4, Some(t[1..].to_vec()), Some(t[0].clone()));
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//Compute challenge
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let challenge = NIZKPublicParams::<E>::hash(proofState.a, vec! {D, rpStateBC.ps1.D, rpStateBC.ps2.D, rpStateBM.ps1.D, rpStateBM.ps2.D});
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//Response phase
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//response for signature
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let oldWalletVec = oldWallet.as_fr_vec();
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let sigProof = self.keypair.prove_response(&proofState, challenge, &mut oldWalletVec.clone());
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//response commitment
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let mut z = Vec::<E::Fr>::with_capacity(t.len());
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let mut z0 = rPrime.clone();
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z0.mul_assign(&challenge);
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z0.add_assign(&t[0]);
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z.push(z0);
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let newWalletVec = newWallet.as_fr_vec();
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for i in 1..t.len() {
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let mut zi = newWalletVec[i - 1].clone();
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zi.mul_assign(&challenge);
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zi.add_assign(&t[i]);
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z.push(zi);
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}
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//response range proof
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let mut vec01 = newWalletVec[0..2].to_vec();
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let mut vecWithout2 = vec01.clone();
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let mut vec3 = newWalletVec[3..].to_vec();
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vecWithout2.append(&mut vec3);
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let mut vec2 = newWalletVec[2].clone();
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vec01.push( vec2);
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if newWalletVec.len() > 4 {
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let mut vec4 = newWalletVec[4..].to_vec();
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vec01.append(&mut vec4);
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}
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let rpBC = self.rpParamsBC.prove_response(rPrime.clone(), &rpStateBC, challenge.clone(), 3, vecWithout2.to_vec());
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let rpBM = self.rpParamsBM.prove_response(rPrime.clone(), &rpStateBM, challenge.clone(), 4, vec01.to_vec());
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Proof { sig: proofState.blindSig, sigProof, D, z, rpBC, rpBM }
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}
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pub fn verify(&self, proof: Proof<E>, epsilon: E::Fr, com2: &Commitment<E>, wpk: E::Fr) -> bool {
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//compute challenge
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let challenge = NIZKPublicParams::<E>::hash(proof.sigProof.a, vec! {proof.D, proof.rpBC.p1.D, proof.rpBC.p2.D, proof.rpBM.p1.D, proof.rpBM.p2.D});
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//verify knowledge of signature
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let r1 = self.keypair.public.verify_proof(&self.mpk, proof.sig, proof.sigProof.clone(), challenge);
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//verify knowledge of commitment
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let mut comc = com2.c.clone();
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comc.mul_assign(challenge.into_repr());
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comc.add_assign(&proof.D.clone());
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let mut x = E::G1::zero();
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for i in 0..proof.z.len() {
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let mut base = self.comParams.pub_bases[i].clone();
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base.mul_assign(proof.z[i].into_repr());
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x.add_assign(&base);
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}
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let r2 = x == comc;
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//verify range proofs
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let r3 = self.rpParamsBC.verify(proof.rpBC.clone(), challenge.clone(), 3);
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let r4 = self.rpParamsBM.verify(proof.rpBM.clone(), challenge.clone(), 4);
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//verify linear relationship
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let mut r5 = proof.z[1] == proof.sigProof.zsig[0];
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let mut zsig2 = proof.sigProof.zsig[2].clone();
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let mut epsC = epsilon.clone();
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epsC.mul_assign(&challenge.clone());
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zsig2.sub_assign(&epsC.clone());
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r5 = r5 && proof.z[3] == zsig2;
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let mut zsig3 = proof.sigProof.zsig[3].clone();
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zsig3.add_assign(&epsC.clone());
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r5 = r5 && proof.z[4] == zsig3;
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r5 = r5 && proof.z[0] == proof.rpBC.p1.zr;
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r5 = r5 && proof.z[0] == proof.rpBC.p2.zr;
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r5 = r5 && proof.z[0] == proof.rpBM.p1.zr;
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r5 = r5 && proof.z[0] == proof.rpBM.p2.zr;
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for i in 1..proof.z.len() {
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if i == 3 {
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r5 = r5 && proof.z[i] == proof.rpBM.p1.zs[i-1];
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r5 = r5 && proof.z[i] == proof.rpBM.p2.zs[i-1].clone();
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} else if i >= 4 {
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r5 = r5 && proof.z[i] == proof.rpBC.p1.zs[i-2].clone();
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r5 = r5 && proof.z[i] == proof.rpBC.p2.zs[i-2].clone();
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} else {
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r5 = r5 && proof.z[i] == proof.rpBC.p1.zs[i-1].clone();
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r5 = r5 && proof.z[i] == proof.rpBC.p2.zs[i-1].clone();
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r5 = r5 && proof.z[i] == proof.rpBM.p1.zs[i-1].clone();
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r5 = r5 && proof.z[i] == proof.rpBM.p2.zs[i-1].clone();
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}
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}
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r1 && r2 && r3 && r4 && r5
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}
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fn hash(a: E::Fqk, T: Vec<E::G1>) -> E::Fr {
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let mut x_vec: Vec<u8> = Vec::new();
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x_vec.extend(format!("{}", a).bytes());
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for t in T {
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x_vec.extend(format!("{}", t).bytes());
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}
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util::hash_to_fr::<E>(x_vec)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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use pairing::bls12_381::{Bls12, Fr};
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#[test]
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fn nizk_proof_works() {
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let rng = &mut rand::thread_rng();
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let pkc = Fr::rand(rng);
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let wpk = Fr::rand(rng);
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let wpkprime = Fr::rand(rng);
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let bc = rng.gen_range(100, 1000);
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let mut bc2 = bc.clone();
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let bm = rng.gen_range(100, 1000);
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let mut bm2 = bm.clone();
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let epsilon = &rng.gen_range(1, 100);
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bc2 -= epsilon;
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bm2 += epsilon;
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let r = Fr::rand(rng);
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let rprime = Fr::rand(rng);
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let pubParams = NIZKPublicParams::<Bls12>::setup(rng, 4);
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let wallet1 = Wallet { pkc, wpk, bc, bm, close: None };
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let commitment1 = pubParams.comParams.commit(&wallet1.as_fr_vec(), &r);
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let wallet2 = Wallet { pkc, wpk: wpkprime, bc: bc2, bm: bm2, close: None };
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let commitment2 = pubParams.comParams.commit(&wallet2.as_fr_vec(), &rprime);
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let blindPaymentToken = pubParams.keypair.sign_blind(rng, &pubParams.mpk, commitment1.clone());
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let paymentToken = pubParams.keypair.unblind(&r, &blindPaymentToken);
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let proof = pubParams.prove(rng, r, wallet1, wallet2,
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commitment2.clone(), rprime, &paymentToken);
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assert_eq!(pubParams.verify(proof, Fr::from_str(&epsilon.to_string()).unwrap(), &commitment2, wpk), true);
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}
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#[test]
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fn nizk_proof_close_works() {
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let rng = &mut rand::thread_rng();
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let pkc = Fr::rand(rng);
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let wpk = Fr::rand(rng);
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let wpkprime = Fr::rand(rng);
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let bc = rng.gen_range(100, 1000);
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let mut bc2 = bc.clone();
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let bm = rng.gen_range(100, 1000);
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let mut bm2 = bm.clone();
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let epsilon = &rng.gen_range(1, 100);
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bc2 -= epsilon;
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bm2 += epsilon;
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let r = Fr::rand(rng);
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let rprime = Fr::rand(rng);
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let pubParams = NIZKPublicParams::<Bls12>::setup(rng, 5);
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let wallet1 = Wallet { pkc, wpk, bc, bm, close: None };
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let commitment1 = pubParams.comParams.commit(&wallet1.as_fr_vec(), &r);
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let closeToken = Fr::rand(rng);
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let wallet2 = Wallet { pkc, wpk: wpkprime, bc: bc2, bm: bm2, close: Some(closeToken) };
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let commitment2 = pubParams.comParams.commit(&wallet2.as_fr_vec(), &rprime);
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let blindPaymentToken = pubParams.keypair.sign_blind(rng, &pubParams.mpk, commitment1.clone());
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let paymentToken = pubParams.keypair.unblind(&r, &blindPaymentToken);
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let proof = pubParams.prove(rng, r, wallet1, wallet2,
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commitment2.clone(), rprime, &paymentToken);
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assert_eq!(pubParams.verify(proof, Fr::from_str(&epsilon.to_string()).unwrap(), &commitment2, wpk), true);
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}
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#[test]
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fn nizk_proof_false_statements() {
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let rng = &mut rand::thread_rng();
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let pkc = Fr::rand(rng);
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let wpk = Fr::rand(rng);
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let wpkprime = Fr::rand(rng);
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let bc = rng.gen_range(100, 1000);
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let mut bc2 = bc.clone();
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let bm = rng.gen_range(100, 1000);
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let mut bm2 = bm.clone();
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let epsilon = &rng.gen_range(1, 100);
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bc2 -= epsilon;
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bm2 += epsilon;
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let r = Fr::rand(rng);
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let rprime = Fr::rand(rng);
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let pubParams = NIZKPublicParams::<Bls12>::setup(rng, 4);
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let wallet1 = Wallet { pkc, wpk, bc, bm, close: None };
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let wallet2 = Wallet::<Bls12> { pkc, wpk: wpkprime, bc: bc2, bm: bm2, close: None };
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let bc2Prime = bc.clone();
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let wallet3 = Wallet { pkc, wpk: wpkprime, bc: bc2Prime, bm: bm2, close: None };
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let commitment1 = pubParams.comParams.commit(&wallet1.as_fr_vec().clone(), &r);
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let commitment2 = pubParams.comParams.commit(&wallet3.as_fr_vec(), &rprime);
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let blindPaymentToken = pubParams.keypair.sign_blind(rng, &pubParams.mpk, commitment1.clone());
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let paymentToken = pubParams.keypair.unblind(&r, &blindPaymentToken);
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let proof = pubParams.prove(rng, r, wallet1.clone(), wallet3, commitment2.clone(), rprime, &paymentToken);
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assert_eq!(pubParams.verify(proof, Fr::from_str(&epsilon.to_string()).unwrap(), &commitment2, wpk), false);
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let bm2Prime = bm.clone();
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let wallet4 = Wallet { pkc, wpk: wpkprime, bc: bc2, bm: bm2Prime, close: None };
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let commitment2 = pubParams.comParams.commit(&wallet4.as_fr_vec(), &rprime);
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let proof = pubParams.prove(rng, r, wallet1.clone(), wallet4, commitment2.clone(), rprime, &paymentToken);
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assert_eq!(pubParams.verify(proof, Fr::from_str(&epsilon.to_string()).unwrap(), &commitment2, wpk), false);
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let wallet5 = Wallet { pkc: Fr::rand(rng), wpk: wpkprime, bc: bc2, bm: bm2, close: None };
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let commitment2 = pubParams.comParams.commit(&wallet5.as_fr_vec(), &rprime);
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let proof = pubParams.prove(rng, r, wallet1.clone(), wallet5, commitment2.clone(), rprime, &paymentToken);
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assert_eq!(pubParams.verify(proof, Fr::from_str(&epsilon.to_string()).unwrap(), &commitment2, wpk), false);
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}
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} |