1 // GoGOST -- Pure Go GOST cryptographic functions library
2 // Copyright (C) 2015-2019 Sergey Matveev <stargrave@stargrave.org>
4 // This program is free software: you can redistribute it and/or modify
5 // it under the terms of the GNU General Public License as published by
6 // the Free Software Foundation, either version 3 of the License, or
7 // (at your option) any later version.
9 // This program is distributed in the hope that it will be useful,
10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 // GNU General Public License for more details.
14 // You should have received a copy of the GNU General Public License
15 // along with this program. If not, see <http://www.gnu.org/licenses/>.
17 // GOST 34.12-2015 128-bit (Кузнечик (Kuznechik)) block cipher.
26 lc [BlockSize]byte = [BlockSize]byte{
27 148, 32, 133, 16, 194, 192, 1, 251, 1, 192, 194, 16,
30 pi [256]byte = [256]byte{
31 252, 238, 221, 17, 207, 110, 49, 22, 251, 196, 250,
32 218, 35, 197, 4, 77, 233, 119, 240, 219, 147, 46,
33 153, 186, 23, 54, 241, 187, 20, 205, 95, 193, 249,
34 24, 101, 90, 226, 92, 239, 33, 129, 28, 60, 66, 139,
35 1, 142, 79, 5, 132, 2, 174, 227, 106, 143, 160, 6,
36 11, 237, 152, 127, 212, 211, 31, 235, 52, 44, 81,
37 234, 200, 72, 171, 242, 42, 104, 162, 253, 58, 206,
38 204, 181, 112, 14, 86, 8, 12, 118, 18, 191, 114, 19,
39 71, 156, 183, 93, 135, 21, 161, 150, 41, 16, 123,
40 154, 199, 243, 145, 120, 111, 157, 158, 178, 177,
41 50, 117, 25, 61, 255, 53, 138, 126, 109, 84, 198,
42 128, 195, 189, 13, 87, 223, 245, 36, 169, 62, 168,
43 67, 201, 215, 121, 214, 246, 124, 34, 185, 3, 224,
44 15, 236, 222, 122, 148, 176, 188, 220, 232, 40, 80,
45 78, 51, 10, 74, 167, 151, 96, 115, 30, 0, 98, 68,
46 26, 184, 56, 130, 100, 159, 38, 65, 173, 69, 70,
47 146, 39, 94, 85, 47, 140, 163, 165, 125, 105, 213,
48 149, 59, 7, 88, 179, 64, 134, 172, 29, 247, 48, 55,
49 107, 228, 136, 217, 231, 137, 225, 27, 131, 73, 76,
50 63, 248, 254, 141, 83, 170, 144, 202, 216, 133, 97,
51 32, 113, 103, 164, 45, 43, 9, 91, 203, 155, 37, 208,
52 190, 229, 108, 82, 89, 166, 116, 210, 230, 244, 180,
53 192, 209, 102, 175, 194, 57, 75, 99, 182,
56 cBlk [32]*[BlockSize]byte
59 func gf(a, b byte) (c byte) {
74 func l(blk *[BlockSize]byte, rounds int) {
77 for ; rounds > 0; rounds-- {
79 for i = 14; i >= 0; i-- {
81 t ^= gf(blk[i], lc[i])
87 func lInv(blk *[BlockSize]byte) {
90 for n := 0; n < BlockSize; n++ {
92 for i = 0; i < 15; i++ {
94 t ^= gf(blk[i], lc[i])
101 piInvP := new([256]byte)
102 for i := 0; i < 256; i++ {
103 piInvP[int(pi[i])] = byte(i)
106 CP := new([32]*[BlockSize]byte)
107 for i := 0; i < 32; i++ {
108 CP[i] = new([BlockSize]byte)
109 CP[i][15] = byte(i) + 1
115 func s(blk *[BlockSize]byte) {
116 for i := 0; i < BlockSize; i++ {
117 blk[i] = pi[int(blk[i])]
121 func xor(dst, src1, src2 *[BlockSize]byte) {
122 for i := 0; i < BlockSize; i++ {
123 dst[i] = src1[i] ^ src2[i]
128 ks [10]*[BlockSize]byte
131 func (c *Cipher) BlockSize() int {
135 func NewCipher(key [KeySize]byte) *Cipher {
136 ks := new([10]*[BlockSize]byte)
137 kr0 := new([BlockSize]byte)
138 kr1 := new([BlockSize]byte)
139 krt := new([BlockSize]byte)
140 copy(kr0[:], key[:BlockSize])
141 copy(kr1[:], key[BlockSize:])
142 ks[0] = new([BlockSize]byte)
143 ks[1] = new([BlockSize]byte)
144 copy(ks[0][:], kr0[:])
145 copy(ks[1][:], kr1[:])
146 for i := 0; i < 4; i++ {
147 for j := 0; j < 8; j++ {
148 xor(krt, kr0, cBlk[8*i+j])
155 ks[2+2*i] = new([BlockSize]byte)
156 copy(ks[2+2*i][:], kr0[:])
157 ks[2+2*i+1] = new([BlockSize]byte)
158 copy(ks[2+2*i+1][:], kr1[:])
163 func (c *Cipher) Encrypt(dst, src []byte) {
164 blk := new([BlockSize]byte)
166 for i := 0; i < 9; i++ {
167 xor(blk, blk, c.ks[i])
171 xor(blk, blk, c.ks[9])
172 copy(dst[:BlockSize], blk[:])
175 func (c *Cipher) Decrypt(dst, src []byte) {
176 blk := new([BlockSize]byte)
179 for i := 9; i > 0; i-- {
180 xor(blk, blk, c.ks[i])
182 for n = 0; n < BlockSize; n++ {
183 blk[n] = piInv[int(blk[n])]
186 xor(blk, blk, c.ks[0])
187 copy(dst[:BlockSize], blk[:])