Revert 030f292 (use libssl if available)

telethon/crypto/libssl.py

@@ -0,0 +1,69 @@
+"""
+Helper module around the system's libssl library if available for IGE mode.
+"""
+import ctypes
+import ctypes.util
+
+
+lib = ctypes.util.find_library('ssl')
+if not lib:
+    decrypt_ige = None
+    encrypt_ige = None
+else:
+    _libssl = ctypes.cdll.LoadLibrary(lib)
+
+    # https://github.com/openssl/openssl/blob/master/include/openssl/aes.h
+    AES_ENCRYPT = ctypes.c_int(1)
+    AES_DECRYPT = ctypes.c_int(0)
+    AES_MAXNR = 14
+
+    class AES_KEY(ctypes.Structure):
+        """Helper class representing an AES key"""
+        _fields_ = [
+            ('rd_key', ctypes.c_uint32 * (4 * (AES_MAXNR + 1))),
+            ('rounds', ctypes.c_uint),
+        ]
+
+    def decrypt_ige(cipher_text, key, iv):
+        aes_key = AES_KEY()
+        key_len = ctypes.c_int(8 * len(key))
+        key = (ctypes.c_ubyte * len(key))(*key)
+        iv = (ctypes.c_ubyte * len(iv))(*iv)
+
+        in_len = ctypes.c_size_t(len(cipher_text))
+        in_ptr = (ctypes.c_ubyte * len(cipher_text))(*cipher_text)
+        out_ptr = (ctypes.c_ubyte * len(cipher_text))()
+
+        _libssl.AES_set_decrypt_key(key, key_len, ctypes.byref(aes_key))
+        _libssl.AES_ige_encrypt(
+            ctypes.byref(in_ptr),
+            ctypes.byref(out_ptr),
+            in_len,
+            ctypes.byref(aes_key),
+            ctypes.byref(iv),
+            AES_DECRYPT
+        )
+
+        return bytes(out_ptr)
+
+    def encrypt_ige(plain_text, key, iv):
+        aes_key = AES_KEY()
+        key_len = ctypes.c_int(8 * len(key))
+        key = (ctypes.c_ubyte * len(key))(*key)
+        iv = (ctypes.c_ubyte * len(iv))(*iv)
+
+        in_len = ctypes.c_size_t(len(plain_text))
+        in_ptr = (ctypes.c_ubyte * len(plain_text))(*plain_text)
+        out_ptr = (ctypes.c_ubyte * len(plain_text))()
+
+        _libssl.AES_set_encrypt_key(key, key_len, ctypes.byref(aes_key))
+        _libssl.AES_ige_encrypt(
+            ctypes.byref(in_ptr),
+            ctypes.byref(out_ptr),
+            in_len,
+            ctypes.byref(aes_key),
+            ctypes.byref(iv),
+            AES_ENCRYPT
+        )
+
+        return bytes(out_ptr)