def des_3round_cryptanalysis_differential(p: List[bytes],
c: List[bytes]) -> List[bytes]:
if len(p) != len(c):
raise ValueError(__name__ +
": count of ciphertext and plaintext does not match")
p_length = len(p)
if p_length == 0:
raise ValueError(__name__ + ": empty text lists")
if p_length % 2 != 0:
raise ValueError(__name__ + ": c_list of odd length")
p_list = list(map(bit_string.bytes_to_bit_string, p))
c_list = list(map(bit_string.bytes_to_bit_string, c))
possible_key_chunks = _des_3round_cryptanalysis_differential_gen_possible_key_chunks(
p_list, c_list)
result = []
for possible_key in _des_3round_iter_possible_keys(possible_key_chunks):
possible_key_bytes = bit_string.bit_string_to_bytes(possible_key)
if list(map(lambda x: des_3round_encrypt(x, possible_key_bytes),
p)) == c:
result.append(possible_key_bytes)
return result
def encrypt(p: bytes, k: bytes) -> bytes:
_des_check(p, k)
key_list = _des_gen_key_list(k)
result = bit_string.bit_string_to_bytes(
_des(bit_string.bytes_to_bit_string(p), key_list))
return result
def des_3round_encrypt(p: bytes, k: bytes) -> bytes:
_des_check(p, k)
key_list = _des_gen_key_list(k)
key_list = key_list[:_des_3round_round_count]
result = bit_string.bit_string_to_bytes(
_des_3round(bit_string.bytes_to_bit_string(p), key_list))
return result
def decrypt(c: bytes, k: bytes) -> bytes:
_des_check(c, k)
key_list = _des_gen_key_list(k)
key_list.reverse()
result = bit_string.bit_string_to_bytes(
_des(bit_string.bytes_to_bit_string(c), key_list))
return result