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  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 -1;
  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.  
  333. #ifdef TEST
  334. #include<stdio.h>
  335. #include<stdlib.h>
  336. #include"log.h"
  337.  
  338. int main(int argc, char *argv[])
  339. {
  340.     uint8_t Key[32] = {0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef, 0xfe, 0xdc, 0xba, 0x98, 0x76, 0x54, 0x32, 0x10, 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77, 0x88, 0x99, 0xaa, 0xbb, 0xcc, 0xdd, 0xee, 0xff
  341.     };
  342.     const uint8_t rct[6][16] = {
  343.         {0x9f, 0x58, 0x9f, 0x5c, 0xf6, 0x12, 0x2c, 0x32, 0xb6, 0xbf, 0xec, 0x2f, 0x2a, 0xe8, 0xc3, 0x5a},
  344.         {0xcf, 0xd1, 0xd2, 0xe5, 0xa9, 0xbe, 0x9c, 0xdf, 0x50, 0x1f, 0x13, 0xb8, 0x92, 0xbd, 0x22, 0x48},
  345.         {0x37, 0x52, 0x7b, 0xe0, 0x05, 0x23, 0x34, 0xb8, 0x9f, 0x0c, 0xfc, 0xca, 0xe8, 0x7c, 0xfa, 0x20},
  346.         {0x5d, 0x9d, 0x4e, 0xef, 0xfa, 0x91, 0x51, 0x57, 0x55, 0x24, 0xf1, 0x15, 0x81, 0x5a, 0x12, 0xe0},
  347.         {0xe7, 0x54, 0x49, 0x21, 0x2b, 0xee, 0xf9, 0xf4, 0xa3, 0x90, 0xbd, 0x86, 0x0a, 0x64, 0x09, 0x41},
  348.         {0x37, 0xfe, 0x26, 0xff, 0x1c, 0xf6, 0x61, 0x75, 0xf5, 0xdd, 0xf4, 0xc3, 0x3b, 0x97, 0xa2, 0x05}
  349.     };
  350.     uint8_t temp[32], iv[16], rpt[32] = {0};
  351.     const int kbits[3] = {128, 192, 256};
  352.     int i, j, err = 0;
  353.     AVTWOFISH *cs;
  354.     cs = av_twofish_alloc();
  355.     if (!cs)
  356.         return 1;
  357.     for (j = 1; j < 3; j++) {
  358.         av_twofish_init(cs, Key, kbits[j]);
  359.         av_twofish_crypt(cs, temp, rpt, 1, NULL, 0);
  360.         for (i = 0; i < 16; i++) {
  361.             if (rct[j][i] != temp[i]) {
  362.                 av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rct[j][i], temp[i]);
  363.                 err = 1;
  364.             }
  365.         }
  366.         av_twofish_crypt(cs, temp, rct[j], 1, NULL, 1);
  367.         for (i = 0; i < 16; i++) {
  368.             if (rpt[i] != temp[i]) {
  369.                 av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rpt[i], temp[i]);
  370.                 err = 1;
  371.             }
  372.         }
  373.     }
  374.     for (j = 0; j < 3; j++) {
  375.         memset(Key, 0, sizeof(Key));
  376.         memset(rpt, 0, sizeof(rpt));
  377.         for (i = 1; i < 50; i++) {
  378.             av_twofish_init(cs, Key, kbits[j]);
  379.             av_twofish_crypt(cs, temp, rpt, 1, NULL, 0);
  380.             memcpy(Key+16,Key,(kbits[j]-128) >> 3);
  381.             memcpy(Key,rpt,16);
  382.             memcpy(rpt,temp,16);
  383.         }
  384.         for (i = 0; i < 16; i++) {
  385.             if (rct[3 + j][i] != temp[i]) {
  386.                 av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rct[3 + j][i], temp[i]);
  387.                 err = 1;
  388.             }
  389.         }
  390.     }
  391.     memset(rpt, 0, sizeof(rpt));
  392.     memcpy(iv, "HALLO123HALLO123", 16);
  393.     av_twofish_crypt(cs, temp, rpt, 2, iv, 0);
  394.     memcpy(iv, "HALLO123HALLO123", 16);
  395.     av_twofish_crypt(cs, temp, temp, 2, iv, 1);
  396.     for (i = 0; i < 32; i++) {
  397.         if (rpt[i] != temp[i]) {
  398.             av_log(NULL, AV_LOG_ERROR, "%d %02x %02x\n", i, rpt[i], temp[i]);
  399.             err = 1;
  400.         }
  401.     }
  402.     av_free(cs);
  403.     return err;
  404. }
  405. #endif
  406.