exclusively use pycryptodome for sha3_256 hashing and always use version 3.3.1 or higher

Author: czepluch

ethereum/keys.py

@@ -23,7 +23,8 @@
 import binascii
 import struct
 from math import ceil
-from sha3 import sha3_256
+from Crypto.Hash import keccak
+sha3_256 = lambda x: keccak.new(digest_bits=256, data=x)
 from Crypto.Cipher import AES
 from Crypto.Hash import SHA256
 from Crypto.Util import Counter

ethereum/utils.py

@@ -1,8 +1,5 @@
-try:
-    from keccak import sha3_256  # pypy
-except ImportError:
-    from sha3 import sha3_256 as _sha3_256
-    sha3_256 = lambda x: _sha3_256(x).digest()
+from Crypto.Hash import keccak
+sha3_256 = lambda x: keccak.new(digest_bits=256, data=x).digest()
 from bitcoin import privtopub
 import sys
 import rlp

requirements.txt

@@ -3,7 +3,7 @@ pysha3
 PyYAML
 repoze.lru
 pbkdf2
-pycrypto
+pycryptodome>=3.3.1
 scrypt
 https://github.com/ethereum/pyrlp/tarball/develop
 https://github.com/ethereum/ethash/tarball/master