Document the crypto/ module

telethon/crypto/__init__.py

@@ -1,3 +1,8 @@
+"""
+This module contains several utilities regarding cryptographic purposes,
+such as the AES IGE mode used by Telegram, the authorization key bound with
+their data centers, and so on.
+"""
 from .aes import AES
 from .aes_ctr import AESModeCTR
 from .auth_key import AuthKey