def decrypt_cdata(data: bytes) -> Tuple[bool, int, int, int]:
decrypted = tgcrypto.ige256_decrypt(data, key, bytes(32))
return (
bool(decrypted[0]),
decrypted[1],
decrypted[2],
int.from_bytes(decrypted[3:7], "little"),
)
def decrypt(self, ciphertext, message_key, mode):
if mode == "org":
mode = 8
else:
mode = 0
msg_key_from_cipher = message_key
kdf = KDF(self.secret_key, msg_key_from_cipher, mode)
aes_key, aes_iv = kdf.KD()
ige_decrypted = tgcrypto.ige256_decrypt(ciphertext[16:], aes_key, aes_iv)
msg_key_large = hashlib.sha256(self.secret_key[88 + mode:120] + ige_decrypted).digest()
msg_key = msg_key_large[8:24]
length = int(ige_decrypted[:32], 2)
if msg_key == msg_key_from_cipher:
plaintext = ige_decrypted[32:32 + length]
return plaintext
else:
print("msg_key mismatch!!!")
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.
"""
# print('using tgcrypto')
return tgcrypto.ige256_decrypt(cipher_text, key, iv)
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)
def test_ige256_decrypt_invalid_args_count(self):
with self.assertRaisesRegex(
TypeError,
r"function takes exactly \d arguments \(\d given\)"):
tgcrypto.ige256_decrypt(os.urandom(16), os.urandom(32))
