优化工单模块，增加企微模块

sg_wechat_enterprise/we_api/crypto/cryptography.py

@@ -0,0 +1,23 @@
+# -*- coding: utf-8 -*-
+from __future__ import absolute_import, unicode_literals
+from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
+from cryptography.hazmat.backends import default_backend
+
+
+class WeChatCipher(object):
+
+    def __init__(self, key):
+        backend = default_backend()
+        self.cipher = Cipher(
+            algorithms.AES(key),
+            modes.CBC(key[:16]),
+            backend=backend
+        )
+
+    def encrypt(self, plaintext):
+        encryptor = self.cipher.encryptor()
+        return encryptor.update(plaintext) + encryptor.finalize()
+
+    def decrypt(self, ciphertext):
+        decryptor = self.cipher.decryptor()
+        return decryptor.update(ciphertext) + decryptor.finalize()