Telethon/telethon/crypto/libssl.py
2018-07-25 12:11:58 +02:00

70 lines
2.0 KiB
Python

"""
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)