Depend only on one library for crypto

* Drops pycrypto dependence
* Supersedes PR #122

miio/extract_tokens.py

@@ -2,7 +2,8 @@
 import click
 import tempfile
 import sqlite3
-from Crypto.Cipher import AES
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.backends import default_backend
 from pprint import pformat as pf
 import attr
 from android_backup import AndroidBackup
@@ -50,8 +51,11 @@ def decrypt_ztoken(ztoken):
 
         keystring = '00000000000000000000000000000000'
         key = bytes.fromhex(keystring)
-        cipher = AES.new(key, AES.MODE_ECB)
-        token = cipher.decrypt(bytes.fromhex(ztoken[:64]))
+        cipher = Cipher(algorithms.AES(key), modes.ECB(),
+                        backend=default_backend())
+        decryptor = cipher.decryptor()
+        token = decryptor.update(bytes.fromhex(ztoken[:64])) \
+                + decryptor.finalize()
 
         return token.decode()
 

requirements.txt

@@ -3,7 +3,6 @@ cryptography
 pretty_cron
 construct
 zeroconf
-pycrypto #  for miio-extract-tokens
 attrs
 typing  # for py3.4 support
 pytz  # for tz offset in vacuum

setup.py

@@ -32,7 +32,6 @@
                       'pretty_cron',
                       'typing; python_version < "3.5"',
                       'zeroconf',
-                      'pycrypto',
                       'attrs',
                       'android_backup',
                       'pytz'],