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libbolt
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blind-sign: complete blind signature + fix commitment

This commit is contained in:
Gijs Van Laer 2019-07-07 16:38:38 -04:00
parent 3c5237f12c
commit 0719018848
2 changed files with 41 additions and 16 deletions
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42
src/cl.rs
View File

@ -289,8 +289,8 @@ impl<E: Engine> BlindKeyPair<E> {
let mut com1 = com.c1.clone();
let mut H1 = self.public.X1.clone();
H1.add_assign(&com1); // (X * com ^ g)
H1.mul_assign(u); // com ^ u (blinding factor)
H1.add_assign(&com1); // (X * com)
H1.mul_assign(u); // (X * com) ^ u (blinding factor)
Signature { h: h1, H: H1 }
}
@ -304,7 +304,8 @@ impl<E: Engine> BlindKeyPair<E> {
/// verifiable with standard signature scheme.
pub fn unblind(&self, bf: &E::Fr, signature: &Signature<E>) -> Signature<E> {
let mut H = signature.h;
let inv_bf = bf.inverse().unwrap();
let mut inv_bf = bf.clone();
inv_bf.negate();
// sigma2 / sigma1 ^ t
H.mul_assign(inv_bf);
@ -411,6 +412,30 @@ mod tests {
assert_eq!(keypair.verify(&mpk,&message1, &t1,&blind_sig), false);
}
#[test]
fn blind_unblind_works() {
let mut rng = &mut rand::thread_rng();
let l = 5;
let mpk = setup(&mut rng);
let keypair = BlindKeyPair::<Bls12>::generate(&mut rng, &mpk, l);
let mut message1 : Vec<Fr> = Vec::new();
for i in 0..l {
message1.push(Fr::rand(&mut rng));
}
let signature = keypair.sign(rng, &message1);
let r = Fr::rand(rng);
let blind_sig = keypair.blind(rng, &r, &signature);
let signature1 = keypair.unblind(&r, &blind_sig);
assert_eq!(keypair.get_public_key(&mpk).verify(&mpk, &message1, &signature1), true);
assert_eq!(keypair.get_public_key(&mpk).verify(&mpk, &message1, &blind_sig), false);
assert_eq!(keypair.verify(&mpk, &message1, &r, &blind_sig), true);
}
#[test]
fn blind_sign_and_verify_works() {
let mut rng = &mut rand::thread_rng();
@ -444,12 +469,11 @@ mod tests {
let t1 = Fr::rand(&mut rng);
assert_eq!(keypair.verify(&mpk,&message1, &t,&unblinded_sig), true);
assert_eq!(keypair.verify(&mpk,&message1, &t, &signature), true);
assert_eq!(keypair.verify(&mpk,&message2, &t,&unblinded_sig), false);
assert_eq!(keypair.verify(&mpk,&message2, &t,&signature), false);
assert_eq!(keypair.verify(&mpk,&message1, &t1,&unblinded_sig), false);
assert_eq!(keypair.verify(&mpk,&message1, &t1,&signature), false);
assert_eq!(keypair.get_public_key(&mpk).verify(&mpk,&message1, &unblinded_sig), true);
assert_eq!(keypair.verify(&mpk,&message1, &t, &signature), true);
assert_eq!(keypair.get_public_key(&mpk).verify(&mpk,&message2, &unblinded_sig), false);
assert_eq!(keypair.verify(&mpk,&message2, &t, &signature), false);
assert_eq!(keypair.verify(&mpk,&message1, &t1, &signature), false);
}
}

15
src/ped92.rs
View File

@ -128,7 +128,8 @@ impl<E: Engine> CSMultiParams<E> {
pub fn setup_gen_params<R: Rng>(rng: &mut R, len: usize) -> Self {
let mut p1: Vec<E::G1> = Vec::new();
let mut p2: Vec<E::G2> = Vec::new();
for i in 0..len {
// 1 extra base element for the random parameter
for i in 0..len + 1 {
p1.push(E::G1::rand(rng));
p2.push(E::G2::rand(rng));
}
@ -142,11 +143,11 @@ impl<E: Engine> CSMultiParams<E> {
let mut c2 = self.pub_bases2[0].clone();
c1.mul_assign(r.clone());
c2.mul_assign(r.clone());
for i in 1..x.len() {
let mut basis1 = self.pub_bases1[i];
for i in 0..x.len() {
let mut basis1 = self.pub_bases1[i+1];
basis1.mul_assign(x[i]);
c1.add_assign(&basis1);
let mut basis2 = self.pub_bases2[i];
let mut basis2 = self.pub_bases2[i+1];
basis2.mul_assign(x[i]);
c2.add_assign(&basis2);
}
@ -162,11 +163,11 @@ impl<E: Engine> CSMultiParams<E> {
let mut dc2 = self.pub_bases2[0].clone();
dc1.mul_assign(r.clone());
dc2.mul_assign(r.clone());
for i in 1..l {
let mut basis1 = self.pub_bases1[i];
for i in 0..l {
let mut basis1 = self.pub_bases1[i+1];
basis1.mul_assign(x[i]);
dc1.add_assign(&basis1);
let mut basis2 = self.pub_bases2[i];
let mut basis2 = self.pub_bases2[i+1];
basis2.mul_assign(x[i]);
dc2.add_assign(&basis2);
}