diff --git a/.hooks/pre-commit b/.hooks/pre-commit
index f3a3b0d..b8a7c30 100755
--- a/.hooks/pre-commit
+++ b/.hooks/pre-commit
@@ -4,7 +4,7 @@ rustfmt --version &>/dev/null
 if [ $? != 0 ]; then
         printf "[pre_commit] \033[0;31merror\033[0m: \"rustfmt\" not available. \n"
         printf "[pre_commit] \033[0;31merror\033[0m: rustfmt can be installed via - \n"
-        printf "[pre_commit] $ rustup component add rustfmt-preview \n"
+        printf "[pre_commit] $ rustup component add rustfmt \n"
         exit 1
 fi
 
@@ -13,7 +13,7 @@ problem_files=()
 # collect ill-formatted files
 for file in $(git diff --name-only --cached); do
         if [ ${file: -3} == ".rs" ]; then
-                rustfmt --check $file &>/dev/null
+                rustfmt +nightly --check $file &>/dev/null
                 if [ $? != 0 ]; then
                         problem_files+=($file)
                 fi
@@ -33,4 +33,4 @@ else
   done
 fi
 
-exit 0
\ No newline at end of file
+exit 0
diff --git a/cp-benches/Cargo.toml b/cp-benches/Cargo.toml
index a97aa0e..018bbfd 100644
--- a/cp-benches/Cargo.toml
+++ b/cp-benches/Cargo.toml
@@ -22,8 +22,8 @@ edition = "2018"
 ################################# Dependencies ################################
 
 [dev-dependencies]
-algebra = { path = "../algebra", default-features = false }
-blake2 = { version = "0.7", default-features = false }
+algebra = { path = "../algebra", default-features = false, features = [ "edwards_bls12" ] }
+blake2 = { version = "0.8", default-features = false }
 criterion = "0.3.1"
 crypto-primitives = { path = "../crypto-primitives" }
 rand = { version = "0.7" }
diff --git a/crypto-primitives/Cargo.toml b/crypto-primitives/Cargo.toml
index 2f12c95..6111856 100644
--- a/crypto-primitives/Cargo.toml
+++ b/crypto-primitives/Cargo.toml
@@ -25,8 +25,8 @@ edition = "2018"
 algebra-core = { path = "../algebra-core", default-features = false }
 bench-utils = { path = "../bench-utils" }
 
-blake2 = { version = "0.7", default-features = false }
-digest = "0.7"
+blake2 = { version = "0.8", default-features = false }
+digest = "0.8"
 
 ff-fft = { path = "../ff-fft", default-features = false }
 gm17 = { path = "../gm17", optional = true, default-features = false }
diff --git a/crypto-primitives/src/prf/blake2s/constraints.rs b/crypto-primitives/src/prf/blake2s/constraints.rs
index f23d620..e3d96a9 100644
--- a/crypto-primitives/src/prf/blake2s/constraints.rs
+++ b/crypto-primitives/src/prf/blake2s/constraints.rs
@@ -530,12 +530,11 @@ impl<ConstraintF: PrimeField> PRFGadget<Blake2s, ConstraintF> for Blake2sGadget
 #[cfg(test)]
 mod test {
     use algebra::jubjub::Fq as Fr;
-    use digest::{FixedOutput, Input};
     use rand::{Rng, SeedableRng};
     use rand_xorshift::XorShiftRng;
 
     use crate::prf::blake2s::{constraints::blake2s_gadget, Blake2s as B2SPRF};
-    use blake2::Blake2s;
+    use blake2::VarBlake2s;
     use r1cs_core::ConstraintSystem;
 
     use super::Blake2sGadget;
@@ -634,13 +633,15 @@ mod test {
         let mut rng = XorShiftRng::seed_from_u64(1231275789u64);
 
         for input_len in (0..32).chain((32..256).filter(|a| a % 8 == 0)) {
-            let mut h = Blake2s::new_keyed(&[], 32);
+            use digest::*;
+            let mut h = VarBlake2s::new_keyed(&[], 32);
 
             let data: Vec<u8> = (0..input_len).map(|_| rng.gen()).collect();
 
-            h.process(&data);
+            h.input(&data);
 
-            let hash_result = h.fixed_result();
+            let mut hash_result = Vec::with_capacity(h.output_size());
+            h.variable_result(|res| hash_result.extend_from_slice(res));
 
             let mut cs = TestConstraintSystem::<Fr>::new();
 
@@ -663,7 +664,6 @@ mod test {
             assert!(cs.is_satisfied());
 
             let mut s = hash_result
-                .as_ref()
                 .iter()
                 .flat_map(|&byte| (0..8).map(move |i| (byte >> i) & 1u8 == 1u8));
 
diff --git a/crypto-primitives/src/prf/blake2s/mod.rs b/crypto-primitives/src/prf/blake2s/mod.rs
index 18c1dc9..0aa15a5 100644
--- a/crypto-primitives/src/prf/blake2s/mod.rs
+++ b/crypto-primitives/src/prf/blake2s/mod.rs
@@ -1,5 +1,5 @@
 use alloc::vec::Vec;
-use blake2::Blake2s as b2s;
+use blake2::{Blake2s as B2s, VarBlake2s};
 use digest::Digest;
 
 use super::PRF;
@@ -18,7 +18,7 @@ impl PRF for Blake2s {
 
     fn evaluate(seed: &Self::Seed, input: &Self::Input) -> Result<Self::Output, CryptoError> {
         let eval_time = start_timer!(|| "Blake2s::Eval");
-        let mut h = b2s::new();
+        let mut h = B2s::new();
         h.input(seed.as_ref());
         h.input(input.as_ref());
         let mut result = [0u8; 32];
@@ -80,10 +80,13 @@ impl Blake2sWithParameterBlock {
     }
 
     pub fn evaluate(&self, input: &[u8]) -> Vec<u8> {
+        use digest::*;
         let eval_time = start_timer!(|| "Blake2sWithParameterBlock::Eval");
-        let mut h = b2s::with_parameter_block(&self.parameters());
+        let mut h = VarBlake2s::with_parameter_block(&self.parameters());
         h.input(input.as_ref());
         end_timer!(eval_time);
-        h.result().to_vec()
+        let mut buf = Vec::with_capacity(h.output_size());
+        h.variable_result(|res| buf.extend_from_slice(res));
+        buf
     }
 }