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css-descramble.c
资源名称：cssdvd.zip　[点击查看]
上传用户：lsh121205
上传日期：2007-01-08
资源大小：25k
文件大小：11k
源码类别：

DVD

开发平台：

C/C++

css-descramble.c：源码内容
  1. /* 
  2.  *  css_descramble.c
  3.  *
  4.  *  Released under the version 2 of the GPL.
  5.  *
  6.  *  Copyright 1999 Derek Fawcus
  7.  *
  8.  *  This file contains functions to descramble CSS encrypted DVD content
  9.  *
  10.  */
  12. /*
  13.  *  Still in progress:  Remove the use of the bit_reverse[] table by recoding
  14.  *                      the generation of LFSR1.  Finish combining this with
  15.  *                      the css authentication code.
  16.  *
  17.  */
  19. #include <stdio.h>
  20. #include <string.h>
  21. #include "css-descramble.h"
  23. typedef unsigned char byte;
  25. /*
  26.  *
  27.  *  some tables used for descrambling sectors and/or decrypting title keys
  28.  *
  29.  */
  31. static byte csstab1[256]=
  32. {
  33. 0x33,0x73,0x3b,0x26,0x63,0x23,0x6b,0x76,0x3e,0x7e,0x36,0x2b,0x6e,0x2e,0x66,0x7b,
  34. 0xd3,0x93,0xdb,0x06,0x43,0x03,0x4b,0x96,0xde,0x9e,0xd6,0x0b,0x4e,0x0e,0x46,0x9b,
  35. 0x57,0x17,0x5f,0x82,0xc7,0x87,0xcf,0x12,0x5a,0x1a,0x52,0x8f,0xca,0x8a,0xc2,0x1f,
  36. 0xd9,0x99,0xd1,0x00,0x49,0x09,0x41,0x90,0xd8,0x98,0xd0,0x01,0x48,0x08,0x40,0x91,
  37. 0x3d,0x7d,0x35,0x24,0x6d,0x2d,0x65,0x74,0x3c,0x7c,0x34,0x25,0x6c,0x2c,0x64,0x75,
  38. 0xdd,0x9d,0xd5,0x04,0x4d,0x0d,0x45,0x94,0xdc,0x9c,0xd4,0x05,0x4c,0x0c,0x44,0x95,
  39. 0x59,0x19,0x51,0x80,0xc9,0x89,0xc1,0x10,0x58,0x18,0x50,0x81,0xc8,0x88,0xc0,0x11,
  40. 0xd7,0x97,0xdf,0x02,0x47,0x07,0x4f,0x92,0xda,0x9a,0xd2,0x0f,0x4a,0x0a,0x42,0x9f,
  41. 0x53,0x13,0x5b,0x86,0xc3,0x83,0xcb,0x16,0x5e,0x1e,0x56,0x8b,0xce,0x8e,0xc6,0x1b,
  42. 0xb3,0xf3,0xbb,0xa6,0xe3,0xa3,0xeb,0xf6,0xbe,0xfe,0xb6,0xab,0xee,0xae,0xe6,0xfb,
  43. 0x37,0x77,0x3f,0x22,0x67,0x27,0x6f,0x72,0x3a,0x7a,0x32,0x2f,0x6a,0x2a,0x62,0x7f,
  44. 0xb9,0xf9,0xb1,0xa0,0xe9,0xa9,0xe1,0xf0,0xb8,0xf8,0xb0,0xa1,0xe8,0xa8,0xe0,0xf1,
  45. 0x5d,0x1d,0x55,0x84,0xcd,0x8d,0xc5,0x14,0x5c,0x1c,0x54,0x85,0xcc,0x8c,0xc4,0x15,
  46. 0xbd,0xfd,0xb5,0xa4,0xed,0xad,0xe5,0xf4,0xbc,0xfc,0xb4,0xa5,0xec,0xac,0xe4,0xf5,
  47. 0x39,0x79,0x31,0x20,0x69,0x29,0x61,0x70,0x38,0x78,0x30,0x21,0x68,0x28,0x60,0x71,
  48. 0xb7,0xf7,0xbf,0xa2,0xe7,0xa7,0xef,0xf2,0xba,0xfa,0xb2,0xaf,0xea,0xaa,0xe2,0xff
  49. };
  51. static byte lfsr1_bits0[256]=
  52. {
  53. 0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x09,0x08,0x0b,0x0a,0x0d,0x0c,0x0f,0x0e,
  54. 0x12,0x13,0x10,0x11,0x16,0x17,0x14,0x15,0x1b,0x1a,0x19,0x18,0x1f,0x1e,0x1d,0x1c,
  55. 0x24,0x25,0x26,0x27,0x20,0x21,0x22,0x23,0x2d,0x2c,0x2f,0x2e,0x29,0x28,0x2b,0x2a,
  56. 0x36,0x37,0x34,0x35,0x32,0x33,0x30,0x31,0x3f,0x3e,0x3d,0x3c,0x3b,0x3a,0x39,0x38,
  57. 0x49,0x48,0x4b,0x4a,0x4d,0x4c,0x4f,0x4e,0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,
  58. 0x5b,0x5a,0x59,0x58,0x5f,0x5e,0x5d,0x5c,0x52,0x53,0x50,0x51,0x56,0x57,0x54,0x55,
  59. 0x6d,0x6c,0x6f,0x6e,0x69,0x68,0x6b,0x6a,0x64,0x65,0x66,0x67,0x60,0x61,0x62,0x63,
  60. 0x7f,0x7e,0x7d,0x7c,0x7b,0x7a,0x79,0x78,0x76,0x77,0x74,0x75,0x72,0x73,0x70,0x71,
  61. 0x92,0x93,0x90,0x91,0x96,0x97,0x94,0x95,0x9b,0x9a,0x99,0x98,0x9f,0x9e,0x9d,0x9c,
  62. 0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,0x89,0x88,0x8b,0x8a,0x8d,0x8c,0x8f,0x8e,
  63. 0xb6,0xb7,0xb4,0xb5,0xb2,0xb3,0xb0,0xb1,0xbf,0xbe,0xbd,0xbc,0xbb,0xba,0xb9,0xb8,
  64. 0xa4,0xa5,0xa6,0xa7,0xa0,0xa1,0xa2,0xa3,0xad,0xac,0xaf,0xae,0xa9,0xa8,0xab,0xaa,
  65. 0xdb,0xda,0xd9,0xd8,0xdf,0xde,0xdd,0xdc,0xd2,0xd3,0xd0,0xd1,0xd6,0xd7,0xd4,0xd5,
  66. 0xc9,0xc8,0xcb,0xca,0xcd,0xcc,0xcf,0xce,0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,
  67. 0xff,0xfe,0xfd,0xfc,0xfb,0xfa,0xf9,0xf8,0xf6,0xf7,0xf4,0xf5,0xf2,0xf3,0xf0,0xf1,
  68. 0xed,0xec,0xef,0xee,0xe9,0xe8,0xeb,0xea,0xe4,0xe5,0xe6,0xe7,0xe0,0xe1,0xe2,0xe3
  69. };
  71. static byte lfsr1_bits1[512]=
  72. {
  73. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  74. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  75. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  76. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  77. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  78. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  79. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  80. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  81. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  82. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  83. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  84. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  85. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  86. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  87. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  88. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  89. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  90. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  91. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  92. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  93. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  94. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  95. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  96. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  97. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  98. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  99. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  100. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  101. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  102. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  103. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
  104. 0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff
  105. };
  107. /* Reverse the order of the bits within a byte.
  108.  */
  109. static byte bit_reverse[256]=
  110. {
  111. 0x00,0x80,0x40,0xc0,0x20,0xa0,0x60,0xe0,0x10,0x90,0x50,0xd0,0x30,0xb0,0x70,0xf0,
  112. 0x08,0x88,0x48,0xc8,0x28,0xa8,0x68,0xe8,0x18,0x98,0x58,0xd8,0x38,0xb8,0x78,0xf8,
  113. 0x04,0x84,0x44,0xc4,0x24,0xa4,0x64,0xe4,0x14,0x94,0x54,0xd4,0x34,0xb4,0x74,0xf4,
  114. 0x0c,0x8c,0x4c,0xcc,0x2c,0xac,0x6c,0xec,0x1c,0x9c,0x5c,0xdc,0x3c,0xbc,0x7c,0xfc,
  115. 0x02,0x82,0x42,0xc2,0x22,0xa2,0x62,0xe2,0x12,0x92,0x52,0xd2,0x32,0xb2,0x72,0xf2,
  116. 0x0a,0x8a,0x4a,0xca,0x2a,0xaa,0x6a,0xea,0x1a,0x9a,0x5a,0xda,0x3a,0xba,0x7a,0xfa,
  117. 0x06,0x86,0x46,0xc6,0x26,0xa6,0x66,0xe6,0x16,0x96,0x56,0xd6,0x36,0xb6,0x76,0xf6,
  118. 0x0e,0x8e,0x4e,0xce,0x2e,0xae,0x6e,0xee,0x1e,0x9e,0x5e,0xde,0x3e,0xbe,0x7e,0xfe,
  119. 0x01,0x81,0x41,0xc1,0x21,0xa1,0x61,0xe1,0x11,0x91,0x51,0xd1,0x31,0xb1,0x71,0xf1,
  120. 0x09,0x89,0x49,0xc9,0x29,0xa9,0x69,0xe9,0x19,0x99,0x59,0xd9,0x39,0xb9,0x79,0xf9,
  121. 0x05,0x85,0x45,0xc5,0x25,0xa5,0x65,0xe5,0x15,0x95,0x55,0xd5,0x35,0xb5,0x75,0xf5,
  122. 0x0d,0x8d,0x4d,0xcd,0x2d,0xad,0x6d,0xed,0x1d,0x9d,0x5d,0xdd,0x3d,0xbd,0x7d,0xfd,
  123. 0x03,0x83,0x43,0xc3,0x23,0xa3,0x63,0xe3,0x13,0x93,0x53,0xd3,0x33,0xb3,0x73,0xf3,
  124. 0x0b,0x8b,0x4b,0xcb,0x2b,0xab,0x6b,0xeb,0x1b,0x9b,0x5b,0xdb,0x3b,0xbb,0x7b,0xfb,
  125. 0x07,0x87,0x47,0xc7,0x27,0xa7,0x67,0xe7,0x17,0x97,0x57,0xd7,0x37,0xb7,0x77,0xf7,
  126. 0x0f,0x8f,0x4f,0xcf,0x2f,0xaf,0x6f,0xef,0x1f,0x9f,0x5f,0xdf,0x3f,0xbf,0x7f,0xff
  127. };
  129. /*
  130.  *
  131.  * this function is only used internally when decrypting title key
  132.  *
  133.  */
  134. static void css_titlekey(byte *key, byte *im, byte invert)
  135. {
  136. unsigned int lfsr1_lo,lfsr1_hi,lfsr0,combined;
  137. byte o_lfsr0, o_lfsr1;
  138. byte k[5];
  139. int i;
  141. lfsr1_lo = im[0] | 0x100;
  142. lfsr1_hi = im[1];
  144. lfsr0 = ((im[4] << 17) | (im[3] << 9) | (im[2] << 1)) + 8 - (im[2]&7);
  145. lfsr0 = (bit_reverse[lfsr0&0xff]<<24) | (bit_reverse[(lfsr0>>8)&0xff] << 16)
  146.   | (bit_reverse[(lfsr0>>16)&0xff]<<8) | bit_reverse[(lfsr0>>24)&0xff];
  148. combined = 0;
  149. for (i = 0; i < 5; ++i) {
  150. o_lfsr1 = lfsr1_bits0[lfsr1_hi] ^ lfsr1_bits1[lfsr1_lo];
  151.   lfsr1_hi = lfsr1_lo>>1;
  152.   lfsr1_lo = ((lfsr1_lo&1)<<8) ^ o_lfsr1;
  153. o_lfsr1 = bit_reverse[o_lfsr1];
  155. /*o_lfsr0 = (lfsr0>>7)^(lfsr0>>10)^(lfsr0>>11)^(lfsr0>>19);*/
  156. o_lfsr0 = (((((((lfsr0>>8)^lfsr0)>>1)^lfsr0)>>3)^lfsr0)>>7);
  157.   lfsr0 = (lfsr0>>8)|(o_lfsr0<<24);
  159. combined += (o_lfsr0 ^ invert) + o_lfsr1;
  160. k[i] = combined & 0xff;
  161. combined >>= 8;
  162. }
  164. key[4]=k[4]^csstab1[key[4]]^key[3];
  165. key[3]=k[3]^csstab1[key[3]]^key[2];
  166. key[2]=k[2]^csstab1[key[2]]^key[1];
  167. key[1]=k[1]^csstab1[key[1]]^key[0];
  168. key[0]=k[0]^csstab1[key[0]]^key[4];
  170. key[4]=k[4]^csstab1[key[4]]^key[3];
  171. key[3]=k[3]^csstab1[key[3]]^key[2];
  172. key[2]=k[2]^csstab1[key[2]]^key[1];
  173. key[1]=k[1]^csstab1[key[1]]^key[0];
  174. key[0]=k[0]^csstab1[key[0]];
  175. }
  177. /*
  178.  *
  179.  * this function decrypts a title key with the specified disk key
  180.  *
  181.  * tkey: the unobfuscated title key (XORed with BusKey)
  182.  * dkey: the unobfuscated disk key (XORed with BusKey)
  183.  *       2048 bytes in length (though only 5 bytes are needed, see below)
  184.  * pkey: array of pointers to player keys and disk key offsets
  185.  *
  186.  *
  187.  * use the result returned in tkey with css_descramble
  188.  *
  189.  */
  191. int css_decrypttitlekey(byte *tkey, byte *dkey, struct playkey **pkey)
  192. {
  193. byte test[5], pretkey[5];
  194. int i = 0;
  196. for (; *pkey; ++pkey, ++i) {
  197. memcpy(pretkey, dkey + (*pkey)->offset, 5);
  198. css_titlekey(pretkey, (*pkey)->key, 0);
  200. memcpy(test, dkey, 5);
  201. css_titlekey(test, pretkey, 0);
  203. if (memcmp(test, pretkey, 5) == 0) {
  204. fprintf(stderr, "Using Key %dn", i+1);
  205. break;
  206. }
  207. }
  209. if (!*pkey) {
  210. fprintf(stderr, "Shit - Need Key %dn", i+1);
  211. return 0;
  212. }
  214. css_titlekey(tkey, pretkey, 0xff);
  216. return 1;
  217. }
  219. /*
  220.  *
  221.  * this function does the actual descrambling
  222.  *
  223.  * sec: encrypted sector (2048 bytes)
  224.  * key: decrypted title key obtained from css_decrypttitlekey
  225.  *
  226.  */
  227. void css_descramble(byte *sec,byte *key)
  228. {
  229. unsigned int lfsr1_lo,lfsr1_hi,lfsr0,combined;
  230. unsigned char o_lfsr0, o_lfsr1;
  231. unsigned char *end = sec + 0x800;
  232. #define SALTED(i) (key[i] ^ sec[0x54 + (i)])
  234. lfsr1_lo = SALTED(0) | 0x100;
  235. lfsr1_hi = SALTED(1);
  237. lfsr0 = ((SALTED(4) << 17) | (SALTED(3) << 9) | (SALTED(2) << 1)) + 8 - (SALTED(2)&7);
  238. lfsr0 = (bit_reverse[lfsr0&0xff]<<24) | (bit_reverse[(lfsr0>>8)&0xff] << 16)
  239.   | (bit_reverse[(lfsr0>>16)&0xff]<<8) | bit_reverse[(lfsr0>>24)&0xff];
  241. sec+=0x80;
  242. combined = 0;
  243. while (sec != end) {
  244. o_lfsr1 = lfsr1_bits0[lfsr1_hi] ^ lfsr1_bits1[lfsr1_lo];
  245.   lfsr1_hi = lfsr1_lo>>1;
  246.   lfsr1_lo = ((lfsr1_lo&1)<<8) ^ o_lfsr1;
  247. o_lfsr1 = bit_reverse[o_lfsr1];
  249. /*o_lfsr0 = (lfsr0>>7)^(lfsr0>>10)^(lfsr0>>11)^(lfsr0>>19);*/
  250. o_lfsr0 = (((((((lfsr0>>8)^lfsr0)>>1)^lfsr0)>>3)^lfsr0)>>7);
  251.   lfsr0 = (lfsr0>>8)|(o_lfsr0<<24);
  253. combined += o_lfsr0 + (byte)~o_lfsr1;
  254. *sec++ = csstab1[*sec] ^ (combined&0xff);
  255. combined >>= 8;
  256. }
  257. }