# coding: utf-8
# PyGOST -- Pure Python GOST cryptographic functions library
-# Copyright (C) 2015-2016 Sergey Matveev <stargrave@stargrave.org>
+# Copyright (C) 2015-2021 Sergey Matveev <stargrave@stargrave.org>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
+# the Free Software Foundation, version 3 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
-"""GOST 34.12-2015 128-bit block cipher Кузнечик (Kuznechik)
-
-:rfc:`7801`. Pay attention that 34.12-2015 also defines 64-bit block
-cipher Магма (Magma) -- it is **not** implemented here.
+"""GOST 34.12-2015 64 and 128 bit block ciphers (:rfc:`7801`)
Several precalculations are performed during this module importing.
"""
+from pygost.gost28147 import block2ns as gost28147_block2ns
+from pygost.gost28147 import decrypt as gost28147_decrypt
+from pygost.gost28147 import encrypt as gost28147_encrypt
+from pygost.gost28147 import ns2block as gost28147_ns2block
from pygost.utils import strxor
from pygost.utils import xrange
+KEYSIZE = 32
+
LC = bytearray((
148, 32, 133, 16, 194, 192, 1, 251, 1, 192, 194, 16, 133, 32, 148, 1,
))
# optimization.
# Actually it can be computed only once and saved on the disk.
########################################################################
+
+
GF = [bytearray(256) for _ in xrange(256)]
+
for x in xrange(256):
for y in xrange(256):
GF[x][y] = gf(x, y)
# Precalculate values of the C -- it does not depend on key.
# Actually it can be computed only once and saved on the disk.
########################################################################
+
+
C = []
+
for x in range(1, 33):
y = bytearray(16)
y[15] = x
return L([PI[v] for v in blk])
-class GOST3412Kuz(object):
+class GOST3412Kuznechik(object):
"""GOST 34.12-2015 128-bit block cipher Кузнечик (Kuznechik)
"""
+ blocksize = 16
+
def __init__(self, key):
"""
:param key: encryption/decryption key
for i in range(9, 0, -1):
blk = [PIinv[v] for v in Linv(bytearray(strxor(self.ks[i], blk)))]
return bytes(strxor(self.ks[0], blk))
+
+
+class GOST3412Magma(object):
+ """GOST 34.12-2015 64-bit block cipher Магма (Magma)
+ """
+ blocksize = 8
+
+ def __init__(self, key):
+ """
+ :param key: encryption/decryption key
+ :type key: bytes, 32 bytes
+ """
+ # Backward compatibility key preparation for 28147-89 key schedule
+ self.key = b"".join(key[i * 4:i * 4 + 4][::-1] for i in range(8))
+ self.sbox = "id-tc26-gost-28147-param-Z"
+
+ def encrypt(self, blk):
+ return gost28147_ns2block(gost28147_encrypt(
+ self.sbox,
+ self.key,
+ gost28147_block2ns(blk[::-1]),
+ ))[::-1]
+
+ def decrypt(self, blk):
+ return gost28147_ns2block(gost28147_decrypt(
+ self.sbox,
+ self.key,
+ gost28147_block2ns(blk[::-1]),
+ ))[::-1]