FFmpeg
twofish.c
Go to the documentation of this file.
1 /*
2  * An implementation of the TwoFish algorithm
3  * Copyright (c) 2015 Supraja Meedinti
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 #include "twofish.h"
22 #include "common.h"
23 #include "intreadwrite.h"
24 #include "attributes.h"
25 
26 #define LR(x, n) ((x) << (n) | (x) >> (32 - (n)))
27 #define RR(x, n) ((x) >> (n) | (x) << (32 - (n)))
28 
29 typedef struct AVTWOFISH {
30  uint32_t K[40];
31  uint32_t S[4];
32  int ksize;
33  uint32_t MDS1[256];
34  uint32_t MDS2[256];
35  uint32_t MDS3[256];
36  uint32_t MDS4[256];
37 } AVTWOFISH;
38 
39 static const uint8_t MD1[256] = {
40  0x00, 0x5b, 0xb6, 0xed, 0x05, 0x5e, 0xb3, 0xe8, 0x0a, 0x51, 0xbc, 0xe7, 0x0f, 0x54, 0xb9, 0xe2,
41  0x14, 0x4f, 0xa2, 0xf9, 0x11, 0x4a, 0xa7, 0xfc, 0x1e, 0x45, 0xa8, 0xf3, 0x1b, 0x40, 0xad, 0xf6,
42  0x28, 0x73, 0x9e, 0xc5, 0x2d, 0x76, 0x9b, 0xc0, 0x22, 0x79, 0x94, 0xcf, 0x27, 0x7c, 0x91, 0xca,
43  0x3c, 0x67, 0x8a, 0xd1, 0x39, 0x62, 0x8f, 0xd4, 0x36, 0x6d, 0x80, 0xdb, 0x33, 0x68, 0x85, 0xde,
44  0x50, 0x0b, 0xe6, 0xbd, 0x55, 0x0e, 0xe3, 0xb8, 0x5a, 0x01, 0xec, 0xb7, 0x5f, 0x04, 0xe9, 0xb2,
45  0x44, 0x1f, 0xf2, 0xa9, 0x41, 0x1a, 0xf7, 0xac, 0x4e, 0x15, 0xf8, 0xa3, 0x4b, 0x10, 0xfd, 0xa6,
46  0x78, 0x23, 0xce, 0x95, 0x7d, 0x26, 0xcb, 0x90, 0x72, 0x29, 0xc4, 0x9f, 0x77, 0x2c, 0xc1, 0x9a,
47  0x6c, 0x37, 0xda, 0x81, 0x69, 0x32, 0xdf, 0x84, 0x66, 0x3d, 0xd0, 0x8b, 0x63, 0x38, 0xd5, 0x8e,
48  0xa0, 0xfb, 0x16, 0x4d, 0xa5, 0xfe, 0x13, 0x48, 0xaa, 0xf1, 0x1c, 0x47, 0xaf, 0xf4, 0x19, 0x42,
49  0xb4, 0xef, 0x02, 0x59, 0xb1, 0xea, 0x07, 0x5c, 0xbe, 0xe5, 0x08, 0x53, 0xbb, 0xe0, 0x0d, 0x56,
50  0x88, 0xd3, 0x3e, 0x65, 0x8d, 0xd6, 0x3b, 0x60, 0x82, 0xd9, 0x34, 0x6f, 0x87, 0xdc, 0x31, 0x6a,
51  0x9c, 0xc7, 0x2a, 0x71, 0x99, 0xc2, 0x2f, 0x74, 0x96, 0xcd, 0x20, 0x7b, 0x93, 0xc8, 0x25, 0x7e,
52  0xf0, 0xab, 0x46, 0x1d, 0xf5, 0xae, 0x43, 0x18, 0xfa, 0xa1, 0x4c, 0x17, 0xff, 0xa4, 0x49, 0x12,
53  0xe4, 0xbf, 0x52, 0x09, 0xe1, 0xba, 0x57, 0x0c, 0xee, 0xb5, 0x58, 0x03, 0xeb, 0xb0, 0x5d, 0x06,
54  0xd8, 0x83, 0x6e, 0x35, 0xdd, 0x86, 0x6b, 0x30, 0xd2, 0x89, 0x64, 0x3f, 0xd7, 0x8c, 0x61, 0x3a,
55  0xcc, 0x97, 0x7a, 0x21, 0xc9, 0x92, 0x7f, 0x24, 0xc6, 0x9d, 0x70, 0x2b, 0xc3, 0x98, 0x75, 0x2e
56 };
57 
58 static const uint8_t MD2[256] = {
59  0x00, 0xef, 0xb7, 0x58, 0x07, 0xe8, 0xb0, 0x5f, 0x0e, 0xe1, 0xb9, 0x56, 0x09, 0xe6, 0xbe, 0x51,
60  0x1c, 0xf3, 0xab, 0x44, 0x1b, 0xf4, 0xac, 0x43, 0x12, 0xfd, 0xa5, 0x4a, 0x15, 0xfa, 0xa2, 0x4d,
61  0x38, 0xd7, 0x8f, 0x60, 0x3f, 0xd0, 0x88, 0x67, 0x36, 0xd9, 0x81, 0x6e, 0x31, 0xde, 0x86, 0x69,
62  0x24, 0xcb, 0x93, 0x7c, 0x23, 0xcc, 0x94, 0x7b, 0x2a, 0xc5, 0x9d, 0x72, 0x2d, 0xc2, 0x9a, 0x75,
63  0x70, 0x9f, 0xc7, 0x28, 0x77, 0x98, 0xc0, 0x2f, 0x7e, 0x91, 0xc9, 0x26, 0x79, 0x96, 0xce, 0x21,
64  0x6c, 0x83, 0xdb, 0x34, 0x6b, 0x84, 0xdc, 0x33, 0x62, 0x8d, 0xd5, 0x3a, 0x65, 0x8a, 0xd2, 0x3d,
65  0x48, 0xa7, 0xff, 0x10, 0x4f, 0xa0, 0xf8, 0x17, 0x46, 0xa9, 0xf1, 0x1e, 0x41, 0xae, 0xf6, 0x19,
66  0x54, 0xbb, 0xe3, 0x0c, 0x53, 0xbc, 0xe4, 0x0b, 0x5a, 0xb5, 0xed, 0x02, 0x5d, 0xb2, 0xea, 0x05,
67  0xe0, 0x0f, 0x57, 0xb8, 0xe7, 0x08, 0x50, 0xbf, 0xee, 0x01, 0x59, 0xb6, 0xe9, 0x06, 0x5e, 0xb1,
68  0xfc, 0x13, 0x4b, 0xa4, 0xfb, 0x14, 0x4c, 0xa3, 0xf2, 0x1d, 0x45, 0xaa, 0xf5, 0x1a, 0x42, 0xad,
69  0xd8, 0x37, 0x6f, 0x80, 0xdf, 0x30, 0x68, 0x87, 0xd6, 0x39, 0x61, 0x8e, 0xd1, 0x3e, 0x66, 0x89,
70  0xc4, 0x2b, 0x73, 0x9c, 0xc3, 0x2c, 0x74, 0x9b, 0xca, 0x25, 0x7d, 0x92, 0xcd, 0x22, 0x7a, 0x95,
71  0x90, 0x7f, 0x27, 0xc8, 0x97, 0x78, 0x20, 0xcf, 0x9e, 0x71, 0x29, 0xc6, 0x99, 0x76, 0x2e, 0xc1,
72  0x8c, 0x63, 0x3b, 0xd4, 0x8b, 0x64, 0x3c, 0xd3, 0x82, 0x6d, 0x35, 0xda, 0x85, 0x6a, 0x32, 0xdd,
73  0xa8, 0x47, 0x1f, 0xf0, 0xaf, 0x40, 0x18, 0xf7, 0xa6, 0x49, 0x11, 0xfe, 0xa1, 0x4e, 0x16, 0xf9,
74  0xb4, 0x5b, 0x03, 0xec, 0xb3, 0x5c, 0x04, 0xeb, 0xba, 0x55, 0x0d, 0xe2, 0xbd, 0x52, 0x0a, 0xe5
75 };
76 
77 static const uint8_t q0[256] = {
78  0xa9, 0x67, 0xb3, 0xe8, 0x04, 0xfd, 0xa3, 0x76, 0x9a, 0x92, 0x80, 0x78, 0xe4, 0xdd, 0xd1, 0x38,
79  0x0d, 0xc6, 0x35, 0x98, 0x18, 0xf7, 0xec, 0x6c, 0x43, 0x75, 0x37, 0x26, 0xfa, 0x13, 0x94, 0x48,
80  0xf2, 0xd0, 0x8b, 0x30, 0x84, 0x54, 0xdf, 0x23, 0x19, 0x5b, 0x3d, 0x59, 0xf3, 0xae, 0xa2, 0x82,
81  0x63, 0x01, 0x83, 0x2e, 0xd9, 0x51, 0x9b, 0x7c, 0xa6, 0xeb, 0xa5, 0xbe, 0x16, 0x0c, 0xe3, 0x61,
82  0xc0, 0x8c, 0x3a, 0xf5, 0x73, 0x2c, 0x25, 0x0b, 0xbb, 0x4e, 0x89, 0x6b, 0x53, 0x6a, 0xb4, 0xf1,
83  0xe1, 0xe6, 0xbd, 0x45, 0xe2, 0xf4, 0xb6, 0x66, 0xcc, 0x95, 0x03, 0x56, 0xd4, 0x1c, 0x1e, 0xd7,
84  0xfb, 0xc3, 0x8e, 0xb5, 0xe9, 0xcf, 0xbf, 0xba, 0xea, 0x77, 0x39, 0xaf, 0x33, 0xc9, 0x62, 0x71,
85  0x81, 0x79, 0x09, 0xad, 0x24, 0xcd, 0xf9, 0xd8, 0xe5, 0xc5, 0xb9, 0x4d, 0x44, 0x08, 0x86, 0xe7,
86  0xa1, 0x1d, 0xaa, 0xed, 0x06, 0x70, 0xb2, 0xd2, 0x41, 0x7b, 0xa0, 0x11, 0x31, 0xc2, 0x27, 0x90,
87  0x20, 0xf6, 0x60, 0xff, 0x96, 0x5c, 0xb1, 0xab, 0x9e, 0x9c, 0x52, 0x1b, 0x5f, 0x93, 0x0a, 0xef,
88  0x91, 0x85, 0x49, 0xee, 0x2d, 0x4f, 0x8f, 0x3b, 0x47, 0x87, 0x6d, 0x46, 0xd6, 0x3e, 0x69, 0x64,
89  0x2a, 0xce, 0xcb, 0x2f, 0xfc, 0x97, 0x05, 0x7a, 0xac, 0x7f, 0xd5, 0x1a, 0x4b, 0x0e, 0xa7, 0x5a,
90  0x28, 0x14, 0x3f, 0x29, 0x88, 0x3c, 0x4c, 0x02, 0xb8, 0xda, 0xb0, 0x17, 0x55, 0x1f, 0x8a, 0x7d,
91  0x57, 0xc7, 0x8d, 0x74, 0xb7, 0xc4, 0x9f, 0x72, 0x7e, 0x15, 0x22, 0x12, 0x58, 0x07, 0x99, 0x34,
92  0x6e, 0x50, 0xde, 0x68, 0x65, 0xbc, 0xdb, 0xf8, 0xc8, 0xa8, 0x2b, 0x40, 0xdc, 0xfe, 0x32, 0xa4,
93  0xca, 0x10, 0x21, 0xf0, 0xd3, 0x5d, 0x0f, 0x00, 0x6f, 0x9d, 0x36, 0x42, 0x4a, 0x5e, 0xc1, 0xe0
94 };
95 
96 static const uint8_t q1[256] = {
97  0x75, 0xf3, 0xc6, 0xf4, 0xdb, 0x7b, 0xfb, 0xc8, 0x4a, 0xd3, 0xe6, 0x6b, 0x45, 0x7d, 0xe8, 0x4b,
98  0xd6, 0x32, 0xd8, 0xfd, 0x37, 0x71, 0xf1, 0xe1, 0x30, 0x0f, 0xf8, 0x1b, 0x87, 0xfa, 0x06, 0x3f,
99  0x5e, 0xba, 0xae, 0x5b, 0x8a, 0x00, 0xbc, 0x9d, 0x6d, 0xc1, 0xb1, 0x0e, 0x80, 0x5d, 0xd2, 0xd5,
100  0xa0, 0x84, 0x07, 0x14, 0xb5, 0x90, 0x2c, 0xa3, 0xb2, 0x73, 0x4c, 0x54, 0x92, 0x74, 0x36, 0x51,
101  0x38, 0xb0, 0xbd, 0x5a, 0xfc, 0x60, 0x62, 0x96, 0x6c, 0x42, 0xf7, 0x10, 0x7c, 0x28, 0x27, 0x8c,
102  0x13, 0x95, 0x9c, 0xc7, 0x24, 0x46, 0x3b, 0x70, 0xca, 0xe3, 0x85, 0xcb, 0x11, 0xd0, 0x93, 0xb8,
103  0xa6, 0x83, 0x20, 0xff, 0x9f, 0x77, 0xc3, 0xcc, 0x03, 0x6f, 0x08, 0xbf, 0x40, 0xe7, 0x2b, 0xe2,
104  0x79, 0x0c, 0xaa, 0x82, 0x41, 0x3a, 0xea, 0xb9, 0xe4, 0x9a, 0xa4, 0x97, 0x7e, 0xda, 0x7a, 0x17,
105  0x66, 0x94, 0xa1, 0x1d, 0x3d, 0xf0, 0xde, 0xb3, 0x0b, 0x72, 0xa7, 0x1c, 0xef, 0xd1, 0x53, 0x3e,
106  0x8f, 0x33, 0x26, 0x5f, 0xec, 0x76, 0x2a, 0x49, 0x81, 0x88, 0xee, 0x21, 0xc4, 0x1a, 0xeb, 0xd9,
107  0xc5, 0x39, 0x99, 0xcd, 0xad, 0x31, 0x8b, 0x01, 0x18, 0x23, 0xdd, 0x1f, 0x4e, 0x2d, 0xf9, 0x48,
108  0x4f, 0xf2, 0x65, 0x8e, 0x78, 0x5c, 0x58, 0x19, 0x8d, 0xe5, 0x98, 0x57, 0x67, 0x7f, 0x05, 0x64,
109  0xaf, 0x63, 0xb6, 0xfe, 0xf5, 0xb7, 0x3c, 0xa5, 0xce, 0xe9, 0x68, 0x44, 0xe0, 0x4d, 0x43, 0x69,
110  0x29, 0x2e, 0xac, 0x15, 0x59, 0xa8, 0x0a, 0x9e, 0x6e, 0x47, 0xdf, 0x34, 0x35, 0x6a, 0xcf, 0xdc,
111  0x22, 0xc9, 0xc0, 0x9b, 0x89, 0xd4, 0xed, 0xab, 0x12, 0xa2, 0x0d, 0x52, 0xbb, 0x02, 0x2f, 0xa9,
112  0xd7, 0x61, 0x1e, 0xb4, 0x50, 0x04, 0xf6, 0xc2, 0x16, 0x25, 0x86, 0x56, 0x55, 0x09, 0xbe, 0x91
113 };
114 
115 struct AVTWOFISH *av_twofish_alloc(void)
116 {
117  return av_mallocz(sizeof(struct AVTWOFISH));
118 }
119 
120 const int av_twofish_size = sizeof(AVTWOFISH);
121 
122 static uint8_t gfmul(uint8_t a, uint8_t b)
123 {
124  uint8_t r = 0, t;
125  while (a && b) {
126  if (a & 1)
127  r = r ^ b;
128  t = b & 0x80;
129  b = b << 1;
130  if (t)
131  b = b ^ 0x4d;
132  a = a >> 1;
133  }
134  return r;
135 }
136 
137 static uint32_t tf_RS(uint32_t k0, uint32_t k1)
138 {
139  uint8_t s[4], m[8];
140  AV_WL32(m, k0);
141  AV_WL32(m + 4, k1);
142  s[0] = gfmul(0x01, m[0]) ^ gfmul(0xa4, m[1]) ^ gfmul(0x55, m[2]) ^ gfmul(0x87, m[3]) ^ gfmul(0x5a, m[4]) ^ gfmul(0x58, m[5]) ^ gfmul(0xdb, m[6]) ^ gfmul(0x9e, m[7]);
143  s[1] = gfmul(0xa4, m[0]) ^ gfmul(0x56, m[1]) ^ gfmul(0x82, m[2]) ^ gfmul(0xf3, m[3]) ^ gfmul(0x1e, m[4]) ^ gfmul(0xc6, m[5]) ^ gfmul(0x68, m[6]) ^ gfmul(0xe5, m[7]);
144  s[2] = gfmul(0x02, m[0]) ^ gfmul(0xa1, m[1]) ^ gfmul(0xfc, m[2]) ^ gfmul(0xc1, m[3]) ^ gfmul(0x47, m[4]) ^ gfmul(0xae, m[5]) ^ gfmul(0x3d, m[6]) ^ gfmul(0x19, m[7]);
145  s[3] = gfmul(0xa4, m[0]) ^ gfmul(0x55, m[1]) ^ gfmul(0x87, m[2]) ^ gfmul(0x5a, m[3]) ^ gfmul(0x58, m[4]) ^ gfmul(0xdb, m[5]) ^ gfmul(0x9e, m[6]) ^ gfmul(0x03, m[7]);
146  return AV_RL32(s);
147 }
148 
149 static void tf_h0(uint8_t y[4], uint32_t L[4], int k)
150 {
151  uint8_t l[4];
152  if (k == 4) {
153  AV_WL32(l, L[3]);
154  y[0] = q1[y[0]] ^ l[0];
155  y[1] = q0[y[1]] ^ l[1];
156  y[2] = q0[y[2]] ^ l[2];
157  y[3] = q1[y[3]] ^ l[3];
158  }
159  if (k >= 3) {
160  AV_WL32(l, L[2]);
161  y[0] = q1[y[0]] ^ l[0];
162  y[1] = q1[y[1]] ^ l[1];
163  y[2] = q0[y[2]] ^ l[2];
164  y[3] = q0[y[3]] ^ l[3];
165  }
166  AV_WL32(l, L[1]);
167  y[0] = q1[q0[q0[y[0]] ^ l[0]] ^ (L[0] & 0xff)];
168  y[1] = q0[q0[q1[y[1]] ^ l[1]] ^ ((L[0] >> 8) & 0xff)];
169  y[2] = q1[q1[q0[y[2]] ^ l[2]] ^ ((L[0] >> 16) & 0xff)];
170  y[3] = q0[q1[q1[y[3]] ^ l[3]] ^ (L[0] >> 24)];
171 }
172 
173 static uint32_t tf_h(uint32_t X, uint32_t L[4], int k)
174 {
175  uint8_t y[4], l[4];
176  AV_WL32(y, X);
177  tf_h0(y, L, k);
178 
179  l[0] = y[0] ^ MD2[y[1]] ^ MD1[y[2]] ^ MD1[y[3]];
180  l[1] = MD1[y[0]] ^ MD2[y[1]] ^ MD2[y[2]] ^ y[3];
181  l[2] = MD2[y[0]] ^ MD1[y[1]] ^ y[2] ^ MD2[y[3]];
182  l[3] = MD2[y[0]] ^ y[1] ^ MD2[y[2]] ^ MD1[y[3]];
183 
184  return AV_RL32(l);
185 }
186 
187 static uint32_t MDS_mul(AVTWOFISH *cs, uint32_t X)
188 {
189  return cs->MDS1[(X) & 0xff] ^ cs->MDS2[((X) >> 8) & 0xff] ^ cs->MDS3[((X) >> 16) & 0xff] ^ cs->MDS4[(X) >> 24];
190 }
191 
192 static void precomputeMDS(AVTWOFISH *cs)
193 {
194  uint8_t y[4];
195  int i;
196  for (i = 0; i < 256; i++) {
197  y[0] = y[1] = y[2] = y[3] = i;
198  tf_h0(y, cs->S, cs->ksize);
199  cs->MDS1[i] = ((uint32_t)y[0]) ^ ((uint32_t)MD1[y[0]] << 8) ^ ((uint32_t)MD2[y[0]] << 16) ^ ((uint32_t)MD2[y[0]] << 24);
200  cs->MDS2[i] = ((uint32_t)MD2[y[1]]) ^ ((uint32_t)MD2[y[1]] << 8) ^ ((uint32_t)MD1[y[1]] << 16) ^ ((uint32_t)y[1] << 24);
201  cs->MDS3[i] = ((uint32_t)MD1[y[2]]) ^ ((uint32_t)MD2[y[2]] << 8) ^ ((uint32_t)y[2] << 16) ^ ((uint32_t)MD2[y[2]] << 24);
202  cs->MDS4[i] = ((uint32_t)MD1[y[3]]) ^ ((uint32_t)y[3] << 8) ^ ((uint32_t)MD2[y[3]] << 16) ^ ((uint32_t)MD1[y[3]] << 24);
203  }
204 }
205 
206 static void twofish_encrypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src)
207 {
208  uint32_t P[4], t0, t1;
209  int i;
210  P[0] = AV_RL32(src) ^ cs->K[0];
211  P[1] = AV_RL32(src + 4) ^ cs->K[1];
212  P[2] = AV_RL32(src + 8) ^ cs->K[2];
213  P[3] = AV_RL32(src + 12) ^ cs->K[3];
214  for (i = 0; i < 16; i += 2) {
215  t0 = MDS_mul(cs, P[0]);
216  t1 = MDS_mul(cs, LR(P[1], 8));
217  P[2] = RR(P[2] ^ (t0 + t1 + cs->K[2 * i + 8]), 1);
218  P[3] = LR(P[3], 1) ^ (t0 + 2 * t1 + cs->K[2 * i + 9]);
219  t0 = MDS_mul(cs, P[2]);
220  t1 = MDS_mul(cs, LR(P[3], 8));
221  P[0] = RR(P[0] ^ (t0 + t1 + cs->K[2 * i + 10]), 1);
222  P[1] = LR(P[1], 1) ^ (t0 + 2 * t1 + cs->K[2 * i + 11]);
223  }
224  P[2] ^= cs->K[4];
225  P[3] ^= cs->K[5];
226  P[0] ^= cs->K[6];
227  P[1] ^= cs->K[7];
228  AV_WL32(dst, P[2]);
229  AV_WL32(dst + 4, P[3]);
230  AV_WL32(dst + 8, P[0]);
231  AV_WL32(dst + 12, P[1]);
232 }
233 
234 static void twofish_decrypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src, uint8_t *iv)
235 {
236  uint32_t P[4], t0, t1;
237  int i;
238  P[2] = AV_RL32(src) ^ cs->K[4];
239  P[3] = AV_RL32(src + 4) ^ cs->K[5];
240  P[0] = AV_RL32(src + 8) ^ cs->K[6];
241  P[1] = AV_RL32(src + 12) ^ cs->K[7];
242  for (i = 15; i >= 0; i -= 2) {
243  t0 = MDS_mul(cs, P[2]);
244  t1 = MDS_mul(cs, LR(P[3], 8));
245  P[0] = LR(P[0], 1) ^ (t0 + t1 + cs->K[2 * i + 8]);
246  P[1] = RR(P[1] ^ (t0 + 2 * t1 + cs->K[2 * i + 9]), 1);
247  t0 = MDS_mul(cs, P[0]);
248  t1 = MDS_mul(cs, LR(P[1], 8));
249  P[2] = LR(P[2], 1) ^ (t0 + t1 + cs->K[2 * i + 6]);
250  P[3] = RR(P[3] ^ (t0 + 2 * t1 + cs->K[2 * i + 7]), 1);
251  }
252  P[0] ^= cs->K[0];
253  P[1] ^= cs->K[1];
254  P[2] ^= cs->K[2];
255  P[3] ^= cs->K[3];
256  if (iv) {
257  P[0] ^= AV_RL32(iv);
258  P[1] ^= AV_RL32(iv + 4);
259  P[2] ^= AV_RL32(iv + 8);
260  P[3] ^= AV_RL32(iv + 12);
261  memcpy(iv, src, 16);
262  }
263  AV_WL32(dst, P[2]);
264  AV_WL32(dst + 4, P[3]);
265  AV_WL32(dst + 8, P[0]);
266  AV_WL32(dst + 12, P[1]);
267 }
268 
269 av_cold int av_twofish_init(AVTWOFISH *cs, const uint8_t *key, int key_bits)
270 {
271  int i;
272  uint8_t keypad[32];
273  uint32_t Key[8], Me[4], Mo[4], A, B;
274  const uint32_t rho = 0x01010101;
275  if (key_bits < 0)
276  return AVERROR(EINVAL);
277  if (key_bits <= 128) {
278  cs->ksize = 2;
279  } else if (key_bits <= 192) {
280  cs->ksize = 3;
281  } else {
282  cs->ksize = 4;
283  }
284  memset(keypad, 0, sizeof(keypad));
285  if (key_bits <= 256) {
286  memcpy(keypad, key, key_bits >> 3);
287  } else {
288  memcpy(keypad, key, 32);
289  }
290  for (i = 0; i < 2 * cs->ksize ; i++)
291  Key[i] = AV_RL32(keypad + 4 * i);
292  for (i = 0; i < cs->ksize; i++) {
293  Me[i] = Key[2 * i];
294  Mo[i] = Key[2 * i + 1];
295  cs->S[cs->ksize - i - 1] = tf_RS(Me[i], Mo[i]);
296  }
297  precomputeMDS(cs);
298  for (i = 0; i < 20; i++) {
299  A = tf_h((2 * i) * rho, Me, cs->ksize);
300  B = tf_h((2 * i + 1) * rho, Mo, cs->ksize);
301  B = LR(B, 8);
302  cs->K[2 * i] = A + B;
303  cs->K[2 * i + 1] = LR((A + (2 * B)), 9);
304  }
305  if (cs->ksize << 6 != key_bits) {
306  return 1;
307  } else {
308  return 0;
309  }
310 }
311 
312 void av_twofish_crypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt)
313 {
314  int i;
315  while (count--) {
316  if (decrypt) {
317  twofish_decrypt(cs, dst, src, iv);
318  } else {
319  if (iv) {
320  for (i = 0; i < 16; i++)
321  dst[i] = src[i] ^ iv[i];
322  twofish_encrypt(cs, dst, dst);
323  memcpy(iv, dst, 16);
324  } else {
325  twofish_encrypt(cs, dst, src);
326  }
327  }
328  src = src + 16;
329  dst = dst + 16;
330  }
331 }
q1
static const uint8_t q1[256]
Definition: twofish.c:96
AVTWOFISH::S
uint32_t S[4]
Definition: twofish.c:31
r
const char * r
Definition: vf_curves.c:114
AVERROR
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFrame structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later. That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another. Frame references ownership and permissions
AVTWOFISH
Definition: twofish.c:29
av_twofish_size
const int av_twofish_size
Definition: twofish.c:120
AV_WL32
#define AV_WL32(p, v)
Definition: intreadwrite.h:426
t0
#define t0
Definition: regdef.h:28
b
#define b
Definition: input.c:41
RR
#define RR(x, n)
Definition: twofish.c:27
t1
#define t1
Definition: regdef.h:29
twofish_encrypt
static void twofish_encrypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src)
Definition: twofish.c:206
AVTWOFISH::K
uint32_t K[40]
Definition: twofish.c:30
MDS_mul
static uint32_t MDS_mul(AVTWOFISH *cs, uint32_t X)
Definition: twofish.c:187
av_twofish_init
av_cold int av_twofish_init(AVTWOFISH *cs, const uint8_t *key, int key_bits)
Initialize an AVTWOFISH context.
Definition: twofish.c:269
A
#define A(x)
Definition: vp56_arith.h:28
AVTWOFISH::MDS2
uint32_t MDS2[256]
Definition: twofish.c:34
precomputeMDS
static void precomputeMDS(AVTWOFISH *cs)
Definition: twofish.c:192
AVTWOFISH::MDS4
uint32_t MDS4[256]
Definition: twofish.c:36
X
@ X
Definition: vf_addroi.c:26
AVTWOFISH::MDS1
uint32_t MDS1[256]
Definition: twofish.c:33
av_twofish_alloc
struct AVTWOFISH * av_twofish_alloc(void)
Allocate an AVTWOFISH context To free the struct: av_free(ptr)
Definition: twofish.c:115
twofish_decrypt
static void twofish_decrypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src, uint8_t *iv)
Definition: twofish.c:234
av_cold
#define av_cold
Definition: attributes.h:90
tf_RS
static uint32_t tf_RS(uint32_t k0, uint32_t k1)
Definition: twofish.c:137
intreadwrite.h
s
#define s(width, name)
Definition: cbs_vp9.c:257
key
const char * key
Definition: hwcontext_opencl.c:168
q0
static const uint8_t q0[256]
Definition: twofish.c:77
AVTWOFISH::MDS3
uint32_t MDS3[256]
Definition: twofish.c:35
MD1
static const uint8_t MD1[256]
Definition: twofish.c:39
src
#define src
Definition: vp8dsp.c:254
av_twofish_crypt
void av_twofish_crypt(AVTWOFISH *cs, uint8_t *dst, const uint8_t *src, int count, uint8_t *iv, int decrypt)
Encrypt or decrypt a buffer using a previously initialized context.
Definition: twofish.c:312
P
#define P
twofish.h
Public header for libavutil TWOFISH algorithm.
a
The reader does not expect b to be semantically here and if the code is changed by maybe adding a a division or other the signedness will almost certainly be mistaken To avoid this confusion a new type was SUINT is the C unsigned type but it holds a signed int to use the same example SUINT a
Definition: undefined.txt:41
attributes.h
AVTWOFISH::ksize
int ksize
Definition: twofish.c:32
i
#define i(width, name, range_min, range_max)
Definition: cbs_h2645.c:269
common.h
uint8_t
uint8_t
Definition: audio_convert.c:194
av_mallocz
void * av_mallocz(size_t size)
Allocate a memory block with alignment suitable for all memory accesses (including vectors if availab...
Definition: mem.c:237
gfmul
static uint8_t gfmul(uint8_t a, uint8_t b)
Definition: twofish.c:122
MD2
static const uint8_t MD2[256]
Definition: twofish.c:58
AV_RL32
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_RL32
Definition: bytestream.h:88
L
#define L(x)
Definition: vp56_arith.h:36
B
#define B
Definition: huffyuvdsp.h:32
LR
#define LR(x, n)
Definition: twofish.c:26
tf_h0
static void tf_h0(uint8_t y[4], uint32_t L[4], int k)
Definition: twofish.c:149
tf_h
static uint32_t tf_h(uint32_t X, uint32_t L[4], int k)
Definition: twofish.c:173
Generated on Wed Aug 24 2022 21:32:08 for FFmpeg by   doxygen 1.8.17