Все подряд

.venv2/Lib/site-packages/telethon/crypto/aes.py

@@ -0,0 +1,111 @@
+"""
+AES IGE implementation in Python.
+
+If available, cryptg will be used instead, otherwise
+if available, libssl will be used instead, otherwise
+the Python implementation will be used.
+"""
+import os
+import pyaes
+import logging
+from . import libssl
+
+
+__log__ = logging.getLogger(__name__)
+
+
+try:
+    import cryptg
+    __log__.info('cryptg detected, it will be used for encryption')
+except ImportError:
+    cryptg = None
+    if libssl.encrypt_ige and libssl.decrypt_ige:
+        __log__.info('libssl detected, it will be used for encryption')
+    else:
+        __log__.info('cryptg module not installed and libssl not found, '
+                     'falling back to (slower) Python encryption')
+
+
+class AES:
+    """
+    Class that servers as an interface to encrypt and decrypt
+    text through the AES IGE mode.
+    """
+    @staticmethod
+    def decrypt_ige(cipher_text, key, iv):
+        """
+        Decrypts the given text in 16-bytes blocks by using the
+        given key and 32-bytes initialization vector.
+        """
+        if cryptg:
+            return cryptg.decrypt_ige(cipher_text, key, iv)
+        if libssl.decrypt_ige:
+            return libssl.decrypt_ige(cipher_text, key, iv)
+
+        iv1 = iv[:len(iv) // 2]
+        iv2 = iv[len(iv) // 2:]
+
+        aes = pyaes.AES(key)
+
+        plain_text = []
+        blocks_count = len(cipher_text) // 16
+
+        cipher_text_block = [0] * 16
+        for block_index in range(blocks_count):
+            for i in range(16):
+                cipher_text_block[i] = \
+                    cipher_text[block_index * 16 + i] ^ iv2[i]
+
+            plain_text_block = aes.decrypt(cipher_text_block)
+
+            for i in range(16):
+                plain_text_block[i] ^= iv1[i]
+
+            iv1 = cipher_text[block_index * 16:block_index * 16 + 16]
+            iv2 = plain_text_block
+
+            plain_text.extend(plain_text_block)
+
+        return bytes(plain_text)
+
+    @staticmethod
+    def encrypt_ige(plain_text, key, iv):
+        """
+        Encrypts the given text in 16-bytes blocks by using the
+        given key and 32-bytes initialization vector.
+        """
+        padding = len(plain_text) % 16
+        if padding:
+            plain_text += os.urandom(16 - padding)
+
+        if cryptg:
+            return cryptg.encrypt_ige(plain_text, key, iv)
+        if libssl.encrypt_ige:
+            return libssl.encrypt_ige(plain_text, key, iv)
+
+        iv1 = iv[:len(iv) // 2]
+        iv2 = iv[len(iv) // 2:]
+
+        aes = pyaes.AES(key)
+
+        cipher_text = []
+        blocks_count = len(plain_text) // 16
+
+        for block_index in range(blocks_count):
+            plain_text_block = list(
+                plain_text[block_index * 16:block_index * 16 + 16]
+            )
+            for i in range(16):
+                plain_text_block[i] ^= iv1[i]
+
+            cipher_text_block = aes.encrypt(plain_text_block)
+
+            for i in range(16):
+                cipher_text_block[i] ^= iv2[i]
+
+            iv1 = cipher_text_block
+            iv2 = plain_text[block_index * 16:block_index * 16 + 16]
+
+            cipher_text.extend(cipher_text_block)
+
+        return bytes(cipher_text)