add aes wrapper (#48)

web3-toolkit/libraries/math_utils.py

@@ -0,0 +1,32 @@
+# -*- encoding: utf-8 -*-
+# math_utils.py
+# This class implements math methods used by the other classes.
+
+
+import base64
+import hashlib
+
+
+def str_to_bytes(data):
+    """Convert string to bytes."""
+    utype = type(b''.decode('utf8'))
+
+    if isinstance(data, utype):
+        return data.encode('utf8')
+
+    return data
+
+
+def b64encode(data: str) -> str:
+    """Encode data to base64."""
+    return base64.b64encode(data).decode('utf-8')
+
+
+def b64decode(data: str) -> str:
+    """Decode base64 data."""
+    return base64.b64decode(data)
+
+
+def hash256(data: str) -> str:
+    """Hash data with SHA-256."""
+    return hashlib.sha256(str_to_bytes(data)).digest()