Sapling commitment tree

librustzcash/src/rustzcash.rs

@@ -11,7 +11,7 @@ extern crate zcash_proofs;
 
 extern crate lazy_static;
 
-use ff::{BitIterator, PrimeField, PrimeFieldRepr};
+use ff::{PrimeField, PrimeFieldRepr};
 use pairing::bls12_381::{Bls12, Fr, FrRepr};
 
 use sapling_crypto::{
@@ -22,7 +22,6 @@ use sapling_crypto::{
         fs::{Fs, FsRepr},
         FixedGenerators, JubjubEngine, JubjubParams, PrimeOrder, ToUniform, Unknown,
     },
-    pedersen_hash::{pedersen_hash, Personalization},
     redjubjub::{self, Signature},
 };
 
@@ -57,10 +56,15 @@ use std::ffi::OsString;
 use std::os::windows::ffi::OsStringExt;
 
 use sapling_crypto::primitives::{ProofGenerationKey, ViewingKey};
-use zcash_primitives::{note_encryption::sapling_ka_agree, sapling::spend_sig, zip32, JUBJUB};
+use zcash_primitives::{
+    merkle_tree::CommitmentTreeWitness,
+    note_encryption::sapling_ka_agree,
+    sapling::{merkle_hash, spend_sig},
+    zip32, JUBJUB,
+};
 use zcash_proofs::{
     load_parameters,
-    sapling::{CommitmentTreeWitness, SaplingProvingContext, SaplingVerificationContext},
+    sapling::{SaplingProvingContext, SaplingVerificationContext},
 };
 
 pub mod equihash;
@@ -254,28 +258,7 @@ pub extern "system" fn librustzcash_merkle_hash(
     // size of the representation
     let b_repr = read_le(unsafe { &(&*b)[..] });
 
-    let mut lhs = [false; 256];
-    let mut rhs = [false; 256];
-
-    for (a, b) in lhs.iter_mut().rev().zip(BitIterator::new(a_repr)) {
-        *a = b;
-    }
-
-    for (a, b) in rhs.iter_mut().rev().zip(BitIterator::new(b_repr)) {
-        *a = b;
-    }
-
-    let tmp = pedersen_hash::<Bls12, _>(
-        Personalization::MerkleTree(depth),
-        lhs.iter()
-            .map(|&x| x)
-            .take(Fr::NUM_BITS as usize)
-            .chain(rhs.iter().map(|&x| x).take(Fr::NUM_BITS as usize)),
-        &JUBJUB,
-    )
-    .into_xy()
-    .0
-    .into_repr();
+    let tmp = merkle_hash(depth, &a_repr, &b_repr);
 
     // Should be okay, caller is responsible for ensuring the pointer
     // is a valid pointer to 32 bytes that can be mutated.

zcash_primitives/src/lib.rs

@@ -17,6 +17,7 @@ use sapling_crypto::jubjub::JubjubBls12;
 
 pub mod block;
 pub mod keys;
+pub mod merkle_tree;
 pub mod note_encryption;
 pub mod sapling;
 mod serialize;