ped92: move commitment to PublicKey

src/ped92.rs

@@ -55,61 +55,59 @@ pub struct CSParams<E: Engine> {
 //    }
 //}
 
-/*
+impl<E: Engine> PublicKey<E> {
+    /*
 Implements the setup algorithm for the Pedersen92 commitment scheme
 */
-pub fn ped92_setup<E: Engine>() -> PublicKey<E> {
-    println!("Run Setup...");
-    let rng = &mut thread_rng();
-    let g = E::G2::rand(rng);
-    let h = E::G2::rand(rng);
-    let pk = PublicKey { g, h };
-    return pk;
-}
+    pub fn setup<R: Rng>(rng: &mut R) -> Self {
+        let g = E::G2::rand(rng);
+        let h = E::G2::rand(rng);
+        let pk = PublicKey { g, h };
+        return pk;
+    }
 
-/*
+    /*
 commit(pk, msg) -> cm where
 - pk is the public key generated from setup()
 - msg is the message structure for the commitment scheme
 - cm is the output commitment message for the given message
 */
-pub fn ped92_commit<E: Engine>(pk: &PublicKey<E>, m: E::Fr, R: Option<E::Fr>) -> Commitment<E> {
-    let rng = &mut thread_rng();
+    pub fn commit<R: Rng>(&self, rng: &mut R, m: E::Fr, R: Option<E::Fr>) -> Commitment<E> {
+        let r = R.unwrap_or(E::Fr::rand(rng));
+        //let r = Fr::random(rng);
 
-    let r = R.unwrap_or(E::Fr::rand(rng));
-    //let r = Fr::random(rng);
+        //let m = msg.hash();
+        let p = "commit -> m";
+        // c = g^m * h^r
+        let mut c = self.g.clone();
+        c.mul_assign(m);
+        let mut h = self.h.clone();
+        h.mul_assign(r);
+        c.add_assign(&h);
+        // return (c, r) <- d=r
+        let commitment = Commitment { c, r };
 
-    //let m = msg.hash();
-    let p = "commit -> m";
-    // c = g^m * h^r
-    let mut c = pk.g.clone();
-    c.mul_assign(m);
-    let mut h = pk.h.clone();
-    h.mul_assign(r);
-    c.add_assign(&h);
-    // return (c, r) <- d=r
-    let commitment = Commitment { c, r };
+        // debugging
+        return commitment;
+    }
 
-    // debugging
-    return commitment;
-}
-
-/*
+    /*
 decommit(pk, cm, msg) -> bool where
 - pk is the public key generated from setup()
 - cm is the commitment
 - m is the message to validate
 - outputs T/F for whether the cm is a valid commitment to the msg
 */
-pub fn ped92_decommit<E: Engine>(pk: &PublicKey<E>, cm: &Commitment<E>, m: E::Fr) -> bool {
-    let p = "decommit -> m";
+    pub fn decommit(&self, cm: &Commitment<E>, m: E::Fr) -> bool {
+        let p = "decommit -> m";
 
-    let mut dm = pk.g.clone();
-    dm.mul_assign(m);
-    let mut h = pk.h.clone();
-    h.mul_assign(cm.r.clone());
-    dm.add_assign(&h);
-    return dm == cm.c;
+        let mut dm = self.g.clone();
+        dm.mul_assign(m);
+        let mut h = self.h.clone();
+        h.mul_assign(cm.r.clone());
+        dm.add_assign(&h);
+        return dm == cm.c;
+    }
 }
 
 
@@ -165,16 +163,16 @@ mod tests {
     #[test]
     fn commit_one_message_works() {
         let rng = &mut thread_rng();
-        let pk = ped92_setup::<Bls12>();
+        let pk = PublicKey::<Bls12>::setup(rng);
 
         let m1 = Fr::rand(rng);
         let mut m2 = m1.clone();
         m2.add_assign(&Fr::one());
         let r = Fr::rand(rng);
-        let c = ped92_commit(&pk, m1, Some(r));
+        let c = pk.commit(rng, m1, Some(r));
 
-        assert_eq!(true, ped92_decommit(&pk, &c, m1));
-        assert_eq!(false, ped92_decommit(&pk, &c, m2));
+        assert_eq!(true, pk.decommit(&c, m1));
+        assert_eq!(false, pk.decommit(&c, m2));
     }
 
     #[test]