Merge pull request #779 from ethereum/JustinDrake-patch-4

Move to SHA256

specs/core/0_beacon-chain.md

@@ -668,7 +668,7 @@ def xor(bytes1: Bytes32, bytes2: Bytes32) -> Bytes32:
 
 ### `hash`
 
-The hash function is denoted by `hash`. In Phase 0 the beacon chain is deployed with the same hash function as Ethereum 1.0, i.e. Keccak-256 (also incorrectly known as SHA3).
+The `hash` function is SHA256.
 
 Note: We aim to migrate to a S[T/N]ARK-friendly hash function in a future Ethereum 2.0 deployment phase.
 

utils/phase0/hash_function.py

@@ -1,7 +1,6 @@
-# from hashlib import sha256
-from eth_utils import keccak
+from hashlib import sha256
+# from eth_utils import keccak
 
 
-# def hash(x): return sha256(x).digest()
-def hash(x):
-    return keccak(x)
+def hash(x): return sha256(x).digest()
+# def hash(x):  return keccak(x)