Switch to using the blake2-rfc crate instead.

Cargo.toml

@@ -14,7 +14,7 @@ features = ["expose-arith"]
 
 [dependencies]
 rand = "0.4"
-blake2 = "0.7"
+blake2-rfc = "0.2.18"
 digest = "0.7"
 bellman = "0.0.9"
 

src/circuit/blake2s.rs

@@ -313,8 +313,7 @@ mod test {
     use ::circuit::test::TestConstraintSystem;
     use super::blake2s;
     use bellman::{ConstraintSystem};
-    use blake2::{Blake2s};
-    use digest::{FixedOutput, Input};
+    use blake2_rfc::blake2s::Blake2s;
 
     #[test]
     fn test_blake2s_constraints() {
@@ -357,13 +356,13 @@ mod test {
 
         for input_len in (0..32).chain((32..256).filter(|a| a % 8 == 0))
         {
-            let mut h = Blake2s::new_keyed(&[], 32);
+            let mut h = Blake2s::new(32);
 
             let data: Vec<u8> = (0..input_len).map(|_| rng.gen()).collect();
 
-            h.process(&data);
+            h.update(&data);
 
-            let hash_result = h.fixed_result();
+            let hash_result = h.finalize();
 
             let mut cs = TestConstraintSystem::<Bls12>::new();
 

src/circuit/test/mod.rs

@@ -16,12 +16,12 @@ use bellman::{
 use std::collections::HashMap;
 use std::fmt::Write;
 
-use blake2::{Blake2s};
-use digest::{FixedOutput, Input};
 use byteorder::{BigEndian, ByteOrder};
 use std::cmp::Ordering;
 use std::collections::BTreeMap;
 
+use blake2_rfc::blake2s::Blake2s;
+
 #[derive(Debug)]
 enum NamedObject {
     Constraint(usize),
@@ -107,7 +107,7 @@ fn hash_lc<E: Engine>(
 
     let mut buf = [0u8; 9 + 32];
     BigEndian::write_u64(&mut buf[0..8], map.len() as u64);
-    h.process(&buf[0..8]);
+    h.update(&buf[0..8]);
 
     for (var, coeff) in map {
         match var.0.get_unchecked() {
@@ -123,7 +123,7 @@ fn hash_lc<E: Engine>(
         
         coeff.into_repr().write_be(&mut buf[9..]).unwrap();
 
-        h.process(&buf);
+        h.update(&buf);
     }
 }
 
@@ -230,14 +230,14 @@ impl<E: Engine> TestConstraintSystem<E> {
     }
 
     pub fn hash(&self) -> String {
-        let mut h = Blake2s::new_keyed(&[], 32);
+        let mut h = Blake2s::new(32);
         {
             let mut buf = [0u8; 24];
 
             BigEndian::write_u64(&mut buf[0..8], self.inputs.len() as u64);
             BigEndian::write_u64(&mut buf[8..16], self.aux.len() as u64);
             BigEndian::write_u64(&mut buf[16..24], self.constraints.len() as u64);
-            h.process(&buf);
+            h.update(&buf);
         }
 
         for constraint in &self.constraints {
@@ -247,7 +247,7 @@ impl<E: Engine> TestConstraintSystem<E> {
         }
 
         let mut s = String::new();
-        for b in h.fixed_result().as_ref() {
+        for b in h.finalize().as_ref() {
             s += &format!("{:02x}", b);
         }
 

src/group_hash.rs

@@ -1,7 +1,6 @@
 use jubjub::*;
 use pairing::*;
-use blake2::{Blake2s};
-use digest::{FixedOutput, Input};
+use blake2_rfc::blake2s::Blake2s;
 
 /// Produces an (x, y) pair (Montgomery) for a
 /// random point in the Jubjub curve. The point
@@ -15,9 +14,9 @@ pub fn group_hash<E: JubjubEngine>(
     // Check to see that scalar field is 255 bits
     assert!(E::Fr::NUM_BITS == 255);
 
-    let mut h = Blake2s::new_keyed(&[], 32);
-    h.process(tag);
-    let mut h = h.fixed_result().to_vec();
+    let mut h = Blake2s::new(32);
+    h.update(tag);
+    let mut h = h.finalize().as_ref().to_vec();
     assert!(h.len() == 32);
 
     // Take first/unset first bit of hash

src/lib.rs

@@ -1,6 +1,6 @@
 extern crate pairing;
 extern crate bellman;
-extern crate blake2;
+extern crate blake2_rfc;
 extern crate digest;
 extern crate rand;