80 lines
2.8 KiB
Python
80 lines
2.8 KiB
Python
|
#
|
||
|
|
# A block cipher is instantiated as a combination of:
|
||
|
|
# 1. A base cipher (such as AES)
|
||
|
|
# 2. A mode of operation (such as CBC)
|
||
|
|
#
|
||
|
|
# Both items are implemented as C modules.
|
||
|
|
#
|
||
|
|
# The API of #1 is (replace "AES" with the name of the actual cipher):
|
||
|
|
# - AES_start_operaion(key) --> base_cipher_state
|
||
|
|
# - AES_encrypt(base_cipher_state, in, out, length)
|
||
|
|
# - AES_decrypt(base_cipher_state, in, out, length)
|
||
|
|
# - AES_stop_operation(base_cipher_state)
|
||
|
|
#
|
||
|
|
# Where base_cipher_state is AES_State, a struct with BlockBase (set of
|
||
|
|
# pointers to encrypt/decrypt/stop) followed by cipher-specific data.
|
||
|
|
#
|
||
|
|
# The API of #2 is (replace "CBC" with the name of the actual mode):
|
||
|
|
# - CBC_start_operation(base_cipher_state) --> mode_state
|
||
|
|
# - CBC_encrypt(mode_state, in, out, length)
|
||
|
|
# - CBC_decrypt(mode_state, in, out, length)
|
||
|
|
# - CBC_stop_operation(mode_state)
|
||
|
|
#
|
||
|
|
# where mode_state is a a pointer to base_cipher_state plus mode-specific data.
|
||
|
|
|
||
|
|
import os
|
||
|
|
|
||
|
|
from Cryptodome.Cipher._mode_ecb import _create_ecb_cipher
|
||
|
|
from Cryptodome.Cipher._mode_cbc import _create_cbc_cipher
|
||
|
|
from Cryptodome.Cipher._mode_cfb import _create_cfb_cipher
|
||
|
|
from Cryptodome.Cipher._mode_ofb import _create_ofb_cipher
|
||
|
|
from Cryptodome.Cipher._mode_ctr import _create_ctr_cipher
|
||
|
|
from Cryptodome.Cipher._mode_openpgp import _create_openpgp_cipher
|
||
|
|
from Cryptodome.Cipher._mode_ccm import _create_ccm_cipher
|
||
|
|
from Cryptodome.Cipher._mode_eax import _create_eax_cipher
|
||
|
|
from Cryptodome.Cipher._mode_siv import _create_siv_cipher
|
||
|
|
from Cryptodome.Cipher._mode_gcm import _create_gcm_cipher
|
||
|
|
from Cryptodome.Cipher._mode_ocb import _create_ocb_cipher
|
||
|
|
|
||
|
|
_modes = { 1:_create_ecb_cipher,
|
||
|
|
2:_create_cbc_cipher,
|
||
|
|
3:_create_cfb_cipher,
|
||
|
|
5:_create_ofb_cipher,
|
||
|
|
6:_create_ctr_cipher,
|
||
|
|
7:_create_openpgp_cipher,
|
||
|
|
9:_create_eax_cipher
|
||
|
|
}
|
||
|
|
|
||
|
|
_extra_modes = { 8:_create_ccm_cipher,
|
||
|
|
10:_create_siv_cipher,
|
||
|
|
11:_create_gcm_cipher,
|
||
|
|
12:_create_ocb_cipher
|
||
|
|
}
|
||
|
|
|
||
|
|
def _create_cipher(factory, key, mode, *args, **kwargs):
|
||
|
|
|
||
|
|
kwargs["key"] = key
|
||
|
|
|
||
|
|
modes = dict(_modes)
|
||
|
|
if kwargs.pop("add_aes_modes", False):
|
||
|
|
modes.update(_extra_modes)
|
||
|
|
if not mode in modes:
|
||
|
|
raise ValueError("Mode not supported")
|
||
|
|
|
||
|
|
if args:
|
||
|
|
if mode in (8, 9, 10, 11, 12):
|
||
|
|
if len(args) > 1:
|
||
|
|
raise TypeError("Too many arguments for this mode")
|
||
|
|
kwargs["nonce"] = args[0]
|
||
|
|
elif mode in (2, 3, 5, 7):
|
||
|
|
if len(args) > 1:
|
||
|
|
raise TypeError("Too many arguments for this mode")
|
||
|
|
kwargs["IV"] = args[0]
|
||
|
|
elif mode == 6:
|
||
|
|
if len(args) > 0:
|
||
|
|
raise TypeError("Too many arguments for this mode")
|
||
|
|
elif mode == 1:
|
||
|
|
raise TypeError("IV is not meaningful for the ECB mode")
|
||
|
|
|
||
|
|
return modes[mode](factory, **kwargs)
|