blind-sign: add commitment in G1
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parent
de9132939a
commit
3c5237f12c
10
src/ccs08.rs
10
src/ccs08.rs
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@ -113,7 +113,7 @@ prove_ul method is used to produce the ZKRP proof that secret x belongs to the i
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let m = E::Fr::rand(rng);
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// D = H^m
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let mut hm = self.com.h.clone();
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let mut hm = self.com.h2.clone();
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hm.mul_assign(m);
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for i in 0..self.l as usize {
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v.push(E::Fr::rand(rng));
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@ -143,7 +143,7 @@ prove_ul method is used to produce the ZKRP proof that secret x belongs to the i
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let ui = self.u.pow(i as u32);
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let mut muiti = t[i].clone();
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muiti.mul_assign(&E::Fr::from_str(&ui.to_string()).unwrap());
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let mut aux = self.com.g.clone();
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let mut aux = self.com.g2.clone();
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aux.mul_assign(muiti);
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D.add_assign(&aux);
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}
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@ -206,17 +206,17 @@ verify_ul is used to validate the ZKRP proof. It returns true iff the proof is v
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}
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fn verify_part1(&self, proof: &ProofUL<E>) -> bool {
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let mut D = proof.comm.c.clone();
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let mut D = proof.comm.c2.clone();
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D.mul_assign(proof.ch);
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D.negate();
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let mut hzr = self.com.h.clone();
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let mut hzr = self.com.h2.clone();
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hzr.mul_assign(proof.zr);
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D.add_assign(&hzr);
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for i in 0..self.l {
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let ui = self.u.pow(i as u32);
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let mut muizsigi = proof.zsig[i as usize];
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muizsigi.mul_assign(&E::Fr::from_str(&ui.to_string()).unwrap());
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let mut aux = self.com.g.clone();
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let mut aux = self.com.g2.clone();
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aux.mul_assign(muizsigi);
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D.add_assign(&aux);
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}
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74
src/cl.rs
74
src/cl.rs
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@ -6,6 +6,7 @@ extern crate rand;
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use super::*;
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use pairing::{CurveAffine, CurveProjective, Engine};
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use rand::Rng;
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use ped92::Commitment;
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#[derive(Clone)]
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pub struct PublicParams<E: Engine> {
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@ -29,7 +30,8 @@ pub struct PublicKey<E: Engine> {
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//#[derive(Clone, Serialize, Deserialize)]
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#[derive(Clone)]
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pub struct BlindPublicKey<E: Engine> {
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pub X: E::G2,
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pub X1: E::G1,
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pub X2: E::G2,
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pub Y1: Vec<E::G1>,
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pub Y2: Vec<E::G2>,
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}
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@ -189,11 +191,15 @@ impl<E: Engine> BlindPublicKey<E> {
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Y1.push(g1y);
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Y2.push(g2y);
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}
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// X = g2 ^ x
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let mut X = mpk.g2;
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X.mul_assign(secret.x);
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// X1 = g1 ^ x
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let mut X1 = mpk.g1;
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X1.mul_assign(secret.x);
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// X2 = g2 ^ x
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let mut X2 = mpk.g2;
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X2.mul_assign(secret.x);
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BlindPublicKey {
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X: X,
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X1: X1,
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X2: X2,
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Y1: Y1,
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Y2: Y2
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}
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@ -216,7 +222,7 @@ impl<E: Engine> BlindPublicKey<E> {
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Yt.mul_assign(message[l]);
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L.add_assign(&Yt);
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let mut X2 = self.X;
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let mut X2 = self.X2;
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X2.add_assign(&L); // X2 = X + L
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let lhs = E::pairing(signature.h, X2);
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let rhs = E::pairing(signature.H, mpk.g2);
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@ -275,6 +281,20 @@ impl<E: Engine> BlindKeyPair<E> {
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self.secret.sign(csprng, message)
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}
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/// sign a commitment of a vector of messages
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pub fn sign_blind<R: Rng>(&self, csprng: &mut R, mpk: &PublicParams<E>, com: Commitment<E>) -> Signature<E> {
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let u = E::Fr::rand(csprng);
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let mut h1 = mpk.g1;
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h1.mul_assign(u); // g1 ^ u
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let mut com1 = com.c1.clone();
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let mut H1 = self.public.X1.clone();
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H1.add_assign(&com1); // (X * com ^ g)
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H1.mul_assign(u); // com ^ u (blinding factor)
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Signature { h: h1, H: H1 }
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}
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/// computes a blind signature from an existing one
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pub fn blind<R: Rng>(&self, csprng: &mut R, bf: &E::Fr, signature: &Signature<E>) -> Signature<E> {
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self.secret.blind(csprng, bf, signature)
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@ -332,6 +352,7 @@ mod tests {
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use pairing::bls12_381::{Bls12, Fr};
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use rand::{SeedableRng};
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use rand_xorshift::XorShiftRng;
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use ped92::CSMultiParams;
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#[test]
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fn sign_and_verify() {
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@ -390,5 +411,46 @@ mod tests {
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assert_eq!(keypair.verify(&mpk,&message1, &t1,&blind_sig), false);
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}
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#[test]
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fn blind_sign_and_verify_works() {
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let mut rng = &mut rand::thread_rng();
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let l = 5;
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let mpk = setup(&mut rng);
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let keypair = BlindKeyPair::<Bls12>::generate(&mut rng, &mpk, l);
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let public_key = keypair.get_public_key(&mpk);
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let mut message1 : Vec<Fr> = Vec::new();
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let mut message2 : Vec<Fr> = Vec::new();
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for i in 0..l {
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message1.push(Fr::rand(&mut rng));
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message2.push(Fr::rand(&mut rng));
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}
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let mut com_bases1 = vec! {mpk.g1};
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com_bases1.append(&mut keypair.public.Y1.clone());
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let mut com_bases2 = vec! {mpk.g2};
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com_bases2.append(&mut keypair.public.Y2.clone());
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let com_params = CSMultiParams { pub_bases1: com_bases1, pub_bases2: com_bases2};
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let t = Fr::rand(rng);
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let com = com_params.commit(rng, &message1, &t);
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let signature = keypair.sign_blind(rng, &mpk, com);
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let unblinded_sig = keypair.unblind(&t, &signature);
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let t1 = Fr::rand(&mut rng);
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assert_eq!(keypair.verify(&mpk,&message1, &t,&unblinded_sig), true);
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assert_eq!(keypair.verify(&mpk,&message1, &t, &signature), true);
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assert_eq!(keypair.verify(&mpk,&message2, &t,&unblinded_sig), false);
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assert_eq!(keypair.verify(&mpk,&message2, &t,&signature), false);
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assert_eq!(keypair.verify(&mpk,&message1, &t1,&unblinded_sig), false);
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assert_eq!(keypair.verify(&mpk,&message1, &t1,&signature), false);
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}
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}
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103
src/ped92.rs
103
src/ped92.rs
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@ -5,18 +5,22 @@ use ff::Rand;
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#[derive(Clone)]
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pub struct CSParams<E: Engine> {
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pub g: E::G2,
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pub h: E::G2,
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pub g1: E::G1,
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pub g2: E::G2,
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pub h1: E::G1,
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pub h2: E::G2,
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}
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#[derive(Clone)]
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pub struct Commitment<E: Engine> {
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pub c: E::G2
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pub c1: E::G1,
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pub c2: E::G2
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}
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#[derive(Clone)]
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pub struct CSMultiParams<E: Engine> {
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pub pub_bases: Vec<E::G2>
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pub pub_bases1: Vec<E::G1>,
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pub pub_bases2: Vec<E::G2>
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}
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//impl<E: Engine> fmt::Display for CSParams<E> {
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@ -59,9 +63,11 @@ impl<E: Engine> CSParams<E> {
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Implements the setup algorithm for the Pedersen92 commitment scheme
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*/
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pub fn setup<R: Rng>(rng: &mut R) -> Self {
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let g = E::G2::rand(rng);
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let h = E::G2::rand(rng);
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let csp = CSParams { g, h };
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let g1 = E::G1::rand(rng);
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let g2 = E::G2::rand(rng);
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let h1 = E::G1::rand(rng);
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let h2 = E::G2::rand(rng);
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let csp = CSParams { g1, g2, h1, h2 };
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return csp;
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}
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@ -74,15 +80,21 @@ commit(pk, msg) -> cm where
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pub fn commit<R: Rng>(&self, rng: &mut R, m: E::Fr, R: Option<E::Fr>) -> Commitment<E> {
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let r = R.unwrap_or(E::Fr::rand(rng));
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let p = "commit -> m";
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// c = g^m * h^r
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let mut c = self.g.clone();
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c.mul_assign(m);
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let mut h = self.h.clone();
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h.mul_assign(r);
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c.add_assign(&h);
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let mut c1 = self.g1.clone();
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c1.mul_assign(m.clone());
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let mut h1 = self.h1.clone();
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h1.mul_assign(r.clone());
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c1.add_assign(&h1);
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Commitment { c }
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// c = g^m * h^r
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let mut c2 = self.g2.clone();
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c2.mul_assign(m);
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let mut h2 = self.h2.clone();
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h2.mul_assign(r);
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c2.add_assign(&h2);
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Commitment { c1, c2 }
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}
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/*
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@ -92,14 +104,18 @@ decommit(csp, cm, msg) -> bool where
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- outputs T/F for whether the cm is a valid commitment to the msg
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*/
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pub fn decommit(&self, cm: &Commitment<E>, m: &E::Fr, r: &E::Fr) -> bool {
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let p = "decommit -> m";
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let mut dm1 = self.g1.clone();
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dm1.mul_assign(m.clone());
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let mut h1 = self.h1.clone();
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h1.mul_assign(r.clone());
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dm1.add_assign(&h1);
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let mut dm = self.g.clone();
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dm.mul_assign(m.clone());
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let mut h = self.h.clone();
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h.mul_assign(r.clone());
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dm.add_assign(&h);
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return dm == cm.c;
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let mut dm2 = self.g2.clone();
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dm2.mul_assign(m.clone());
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let mut h2 = self.h2.clone();
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h2.mul_assign(r.clone());
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dm2.add_assign(&h2);
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return dm2 == cm.c2 && dm1 == cm.c1;
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}
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}
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@ -110,40 +126,51 @@ impl<E: Engine> CSMultiParams<E> {
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a vector of messages.
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*/
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pub fn setup_gen_params<R: Rng>(rng: &mut R, len: usize) -> Self {
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let mut p: Vec<E::G2> = Vec::new();
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let mut p1: Vec<E::G1> = Vec::new();
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let mut p2: Vec<E::G2> = Vec::new();
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for i in 0..len {
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p.push(E::G2::rand(rng));
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p1.push(E::G1::rand(rng));
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p2.push(E::G2::rand(rng));
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}
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return CSMultiParams { pub_bases: p };
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return CSMultiParams { pub_bases1: p1, pub_bases2: p2 };
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}
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pub fn commit<R: Rng>(&self, rng: &mut R, x: &Vec<E::Fr>, r: &E::Fr) -> Commitment<E> {
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//let r = R.unwrap_or(Fr::random(rng));
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// c = g1^m1 * ... * gn^mn * h^r
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let mut c = self.pub_bases[0].clone();
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c.mul_assign(r.clone());
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let mut c1 = self.pub_bases1[0].clone();
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let mut c2 = self.pub_bases2[0].clone();
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c1.mul_assign(r.clone());
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c2.mul_assign(r.clone());
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for i in 1..x.len() {
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let mut basis = self.pub_bases[i];
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basis.mul_assign(x[i]);
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c.add_assign(&basis);
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let mut basis1 = self.pub_bases1[i];
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basis1.mul_assign(x[i]);
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c1.add_assign(&basis1);
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let mut basis2 = self.pub_bases2[i];
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basis2.mul_assign(x[i]);
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c2.add_assign(&basis2);
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}
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// return (c, r) <- r
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Commitment { c: c }
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Commitment { c1, c2 }
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}
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pub fn decommit(&self, cm: &Commitment<E>, x: &Vec<E::Fr>, r: &E::Fr) -> bool {
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let l = x.len();
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// pub_base[0] => h, x[0] => r
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// check that cm.r == x[0]
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let cr = r.clone();
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let mut dc = self.pub_bases[0].clone();
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dc.mul_assign(cr);
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let mut dc1 = self.pub_bases1[0].clone();
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let mut dc2 = self.pub_bases2[0].clone();
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dc1.mul_assign(r.clone());
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dc2.mul_assign(r.clone());
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for i in 1..l {
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let mut basis = self.pub_bases[i];
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basis.mul_assign(x[i]);
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dc.add_assign(&basis);
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let mut basis1 = self.pub_bases1[i];
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basis1.mul_assign(x[i]);
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dc1.add_assign(&basis1);
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let mut basis2 = self.pub_bases2[i];
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basis2.mul_assign(x[i]);
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dc2.add_assign(&basis2);
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}
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return dc == cm.c && cr == x[0];
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return dc2 == cm.c2 && dc1 == cm.c1;
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}
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}
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@ -178,7 +205,7 @@ mod tests {
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for i in 0..len {
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m.push(Fr::rand(rng));
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}
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let r = m[0].clone();
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let r = Fr::rand(rng);
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let c = csp.commit(rng, &m, &r);
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assert_eq!(csp.decommit(&c, &m, &r), true);
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