Refactor the util directory to use subpackages.

util/security/aes.py

@@ -0,0 +1,32 @@
+import base64
+import hashlib
+from Crypto import Random
+from Crypto.Cipher import AES
+
+class AESCipher(object):
+  """ Helper class for encrypting and decrypting data via AES.
+
+      Copied From: http://stackoverflow.com/a/21928790
+  """
+  def __init__(self, key):
+    self.bs = 32
+    self.key = key
+
+  def encrypt(self, raw):
+    raw = self._pad(raw)
+    iv = Random.new().read(AES.block_size)
+    cipher = AES.new(self.key, AES.MODE_CBC, iv)
+    return base64.b64encode(iv + cipher.encrypt(raw))
+
+  def decrypt(self, enc):
+    enc = base64.b64decode(enc)
+    iv = enc[:AES.block_size]
+    cipher = AES.new(self.key, AES.MODE_CBC, iv)
+    return self._unpad(cipher.decrypt(enc[AES.block_size:])).decode('utf-8')
+
+  def _pad(self, s):
+    return s + (self.bs - len(s) % self.bs) * chr(self.bs - len(s) % self.bs)
+
+  @staticmethod
+  def _unpad(s):
+    return s[:-ord(s[len(s)-1:])]