swap (pp)snark with zksnark, make pedersen zk, add nizk, update corre…

…sp fns

src/nifs.rs

@@ -11,6 +11,8 @@ use crate::{
   traits::{commitment::CommitmentTrait, AbsorbInROTrait, Engine, ROConstants, ROTrait},
   Commitment, CommitmentKey, CompressedCommitment,
 };
+use ff::Field;
+use rand::rngs::OsRng;
 use serde::{Deserialize, Serialize};
 
 /// A SNARK that holds the proof of a step of an incremental computation
@@ -72,7 +74,8 @@ impl<E: Engine> NIFS<E> {
     U2.absorb_in_ro(&mut ro);
 
     // compute a commitment to the cross-term
-    let (T, comm_T) = S.commit_T(ck, U1, W1, U2, W2)?;
+    let r_T = E::Scalar::random(&mut OsRng);
+    let (T, comm_T) = S.commit_T(ck, U1, W1, U2, W2, &r_T)?;
 
     // append `comm_T` to the transcript and obtain a challenge
     comm_T.absorb_in_ro(&mut ro);
@@ -84,7 +87,7 @@ impl<E: Engine> NIFS<E> {
     let U = U1.fold(U2, &comm_T, &r);
 
     // fold the witness using `r` and `T`
-    let W = W1.fold(W2, &T, &r)?;
+    let W = W1.fold(W2, &T, &r_T, &r)?;
 
     // return the folded instance and witness
     Ok((
@@ -126,7 +129,8 @@ impl<E: Engine> NIFS<E> {
     U2.absorb_in_ro(&mut ro);
 
     // compute a commitment to the cross-term
-    let comm_T = S.commit_T_into(ck, U1, W1, U2, W2, T, ABC_Z_1, ABC_Z_2)?;
+    let r_T = E::Scalar::random(&mut OsRng);
+    let comm_T = S.commit_T_into(ck, U1, W1, U2, W2, T, ABC_Z_1, ABC_Z_2, &r_T)?;
 
     // append `comm_T` to the transcript and obtain a challenge
     comm_T.absorb_in_ro(&mut ro);

src/provider/bn256_grumpkin.rs

@@ -6,7 +6,7 @@ use crate::{
 };
 use digest::{ExtendableOutput, Update};
 use ff::{FromUniformBytes, PrimeField};
-use group::{cofactor::CofactorCurveAffine, Curve, Group as AnotherGroup};
+use group::{cofactor::CofactorCurveAffine, Curve, Group as AnotherGroup, GroupEncoding};
 #[cfg(any(target_arch = "x86_64", target_arch = "aarch64"))]
 use grumpkin_msm::{bn256 as bn256_msm, grumpkin as grumpkin_msm};
 // Remove this when https://github.com/zcash/pasta_curves/issues/41 resolves