Allow using pysha3 instead of pycryptodomex

monero/keccak.py

@@ -1,10 +1,21 @@
-from Cryptodome.Hash import keccak
+cd_keccak = None
+sha3_keccak = None
+
+try:
+    from Cryptodome.Hash import cd_keccak
+except ImportError:
+    from sha3 import keccak_256 as sha3_keccak
 
 
 def keccak_256(data):
     """
     Return a hashlib-compatible Keccak 256 object for the given data.
     """
-    hash = keccak.new(digest_bits=256)
-    hash.update(data)
-    return hash
+    if cd_keccak is not None:
+        h = cd_keccak.new(digest_bits=256)
+        h.update(data)
+    elif sha3_keccak is not None:
+        h = sha3_keccak(data)
+    else:   # pragma: no cover
+        raise RuntimeError("SHA3 implementation is missing. Install either 'pycryptodomex' (recommended) or 'pysha3' package to provide it")
+    return h