blob: d84fa4f363a09327b89d22b9cd9ab2a76b2430f6
| 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 | } |
| 332 |