¡@
OpenStack Study: crypt.py**** CubicPower OpenStack Study **** def urlsafe_encrypt(key, plaintext, blocksize=16): """ Encrypts plaintext. Resulting ciphertext will contain URL-safe characters :param key: AES secret key :param plaintext: Input text to be encrypted :param blocksize: Non-zero integer multiple of AES blocksize in bytes (16) :returns : Resulting ciphertext """ def pad(text): """ Pads text to be encrypted """ pad_length = (blocksize - len(text) % blocksize) sr = random.StrongRandom() pad = ''.join(chr(sr.randint(1, 0xFF)) for i in range(pad_length - 1)) # We use chr(0) as a delimiter between text and padding return text + chr(0) + pad # random initial 16 bytes for CBC init_vector = Random.get_random_bytes(16) cypher = AES.new(key, AES.MODE_CBC, init_vector) padded = cypher.encrypt(pad(str(plaintext))) return base64.urlsafe_b64encode(init_vector + padded)
**** CubicPower OpenStack Study **** def urlsafe_decrypt(key, ciphertext): """ Decrypts URL-safe base64 encoded ciphertext :param key: AES secret key :param ciphertext: The encrypted text to decrypt :returns : Resulting plaintext """ # Cast from unicode ciphertext = base64.urlsafe_b64decode(str(ciphertext)) cypher = AES.new(key, AES.MODE_CBC, ciphertext[:16]) padded = cypher.decrypt(ciphertext[16:]) return padded[:padded.rfind(chr(0))]
|