1 /*****************************************************************************
2 * css.c: Functions for DVD authentification and unscrambling
3 *****************************************************************************
4 * Copyright (C) 1999-2001 VideoLAN
5 * $Id: css.c,v 1.4 2001/07/07 21:10:58 gbazin Exp $
7 * Author: Stéphane Borel <stef@via.ecp.fr>
10 * - css-auth by Derek Fawcus <derek@spider.com>
11 * - DVD CSS ioctls example program by Andrew T. Veliath <andrewtv@usa.net>
12 * - The Divide and conquer attack by Frank A. Stevenson <frank@funcom.com>
13 * - DeCSSPlus by Ethan Hawke
15 * see http://www.lemuria.org/DeCSS/ by Tom Vogt for more information.
17 * This program is free software; you can redistribute it and/or modify
18 * it under the terms of the GNU General Public License as published by
19 * the Free Software Foundation; either version 2 of the License, or
20 * (at your option) any later version.
22 * This program is distributed in the hope that it will be useful,
23 * but WITHOUT ANY WARRANTY; without even the implied warranty of
24 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
25 * GNU General Public License for more details.
27 * You should have received a copy of the GNU General Public License
28 * along with this program; if not, write to the Free Software
29 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
30 *****************************************************************************/
32 /*****************************************************************************
34 *****************************************************************************/
45 #include "videolan/dvdcss.h"
46 #include "libdvdcss.h"
49 # include "csstables.h"
53 /*****************************************************************************
55 *****************************************************************************/
57 static int CSSGetASF ( dvdcss_handle dvdcss );
58 static void CSSCryptKey ( int i_key_type, int i_varient,
59 u8 const * pi_challenge, u8* pi_key );
60 static int CSSCracker ( int i_start, unsigned char * p_crypted,
61 unsigned char * p_decrypted,
62 dvd_key_t * p_sector_key, dvd_key_t * p_key );
65 /*****************************************************************************
66 * CSSTest : check if the disc is encrypted or not
67 *****************************************************************************/
68 int CSSTest( dvdcss_handle dvdcss )
70 int i_ret, i_copyright;
72 i_ret = ioctl_ReadCopyright( dvdcss->i_fd, 0 /* i_layer */, &i_copyright );
76 /* Since it's the first ioctl we try to issue, we add a notice */
77 _dvdcss_error( dvdcss, "css error: ioctl_ReadCopyright failed, "
78 "make sure DVD ioctls were compiled in" );
86 /*****************************************************************************
87 * CSSInit : CSS Structure initialisation and DVD authentication.
88 *****************************************************************************
89 * It simulates the mutual authentication between logical unit and host.
90 * Since we don't need the disc key to find the title key, we just run the
91 * basic unavoidable commands to authenticate device and disc.
92 *****************************************************************************/
93 int CSSInit( dvdcss_handle dvdcss )
96 /* structures defined in cdrom.h or dvdio.h */
97 char p_buffer[2048 + 4 + 1];
103 /* Test authentication success */
104 switch( CSSGetASF( dvdcss ) )
110 _dvdcss_debug( dvdcss, "already authenticated" );
114 _dvdcss_debug( dvdcss, "need to authenticate" );
117 /* Init sequence, request AGID */
118 for( i = 1; i < 4 ; ++i )
120 sprintf( psz_warning, "requesting AGID %d", i );
121 _dvdcss_debug( dvdcss, psz_warning );
123 i_ret = ioctl_ReportAgid( dvdcss->i_fd, &i_agid );
127 /* No error during ioctl: we know the device is authenticated */
131 _dvdcss_error( dvdcss, "ioctl_ReportAgid failed, invalidating" );
134 ioctl_InvalidateAgid( dvdcss->i_fd, &i_agid );
137 /* Unable to authenticate without AGID */
140 _dvdcss_error( dvdcss, "ioctl_ReportAgid failed, fatal" );
144 for( i = 0 ; i < 10; ++i )
146 dvdcss->css.disc.pi_challenge[i] = i;
149 /* Get challenge from host */
150 for( i = 0 ; i < 10 ; ++i )
152 p_buffer[9-i] = dvdcss->css.disc.pi_challenge[i];
155 /* Send challenge to LU */
156 if( ioctl_SendChallenge( dvdcss->i_fd, &i_agid, p_buffer ) < 0 )
158 _dvdcss_error( dvdcss, "ioctl_SendChallenge failed" );
162 /* Get key1 from LU */
163 if( ioctl_ReportKey1( dvdcss->i_fd, &i_agid, p_buffer ) < 0)
165 _dvdcss_error( dvdcss, "ioctl_ReportKey1 failed" );
169 /* Send key1 to host */
170 for( i = 0 ; i < KEY_SIZE ; i++ )
172 dvdcss->css.disc.pi_key1[i] = p_buffer[4-i];
175 for( i = 0 ; i < 32 ; ++i )
177 CSSCryptKey( 0, i, dvdcss->css.disc.pi_challenge,
178 dvdcss->css.disc.pi_key_check );
180 if( memcmp( dvdcss->css.disc.pi_key_check,
181 dvdcss->css.disc.pi_key1, KEY_SIZE ) == 0 )
183 sprintf( psz_warning, "drive authentic, using variant %d", i );
184 _dvdcss_debug( dvdcss, psz_warning );
185 dvdcss->css.disc.i_varient = i;
192 _dvdcss_error( dvdcss, "drive would not authenticate" );
196 /* Get challenge from LU */
197 if( ioctl_ReportChallenge( dvdcss->i_fd, &i_agid, p_buffer ) < 0 )
199 _dvdcss_error( dvdcss, "ioctl_ReportKeyChallenge failed" );
203 /* Send challenge to host */
204 for( i = 0 ; i < 10 ; ++i )
206 dvdcss->css.disc.pi_challenge[i] = p_buffer[9-i];
209 CSSCryptKey( 1, dvdcss->css.disc.i_varient,
210 dvdcss->css.disc.pi_challenge,
211 dvdcss->css.disc.pi_key2 );
213 /* Get key2 from host */
214 for( i = 0 ; i < KEY_SIZE ; ++i )
216 p_buffer[4-i] = dvdcss->css.disc.pi_key2[i];
219 /* Send key2 to LU */
220 if( ioctl_SendKey2( dvdcss->i_fd, &i_agid, p_buffer ) < 0 )
222 _dvdcss_error( dvdcss, "ioctl_SendKey2 failed" );
226 _dvdcss_debug( dvdcss, "authentication established" );
228 memcpy( dvdcss->css.disc.pi_challenge,
229 dvdcss->css.disc.pi_key1, KEY_SIZE );
230 memcpy( dvdcss->css.disc.pi_challenge+KEY_SIZE,
231 dvdcss->css.disc.pi_key2, KEY_SIZE );
233 CSSCryptKey( 2, dvdcss->css.disc.i_varient,
234 dvdcss->css.disc.pi_challenge,
235 dvdcss->css.disc.pi_key_check );
237 _dvdcss_debug( dvdcss, "received session key" );
244 /* Test authentication success */
245 switch( CSSGetASF( dvdcss ) )
251 _dvdcss_debug( dvdcss, "already authenticated" );
255 _dvdcss_debug( dvdcss, "need to get disc key" );
258 /* Get encrypted disc key */
259 if( ioctl_ReadKey( dvdcss->i_fd, &i_agid, p_buffer ) < 0 )
261 _dvdcss_error( dvdcss, "ioctl_ReadKey failed" );
265 fprintf( stderr, "DISK KEY: %02x %02x %02x %02x %02x\n", p_buffer[0], p_buffer[1], p_buffer[2], p_buffer[3], p_buffer[4] );
267 /* Unencrypt disc key using bus key */
268 for( i = 0 ; i < 2048 ; i++ )
270 p_buffer[ i ] ^= dvdcss->css.disc.pi_key_check[ 4 - (i % KEY_SIZE) ];
272 memcpy( dvdcss->css.disc.pi_key_check, p_buffer, 2048 );
274 /* initialize title key to know it empty */
275 for( i = 0 ; i < KEY_SIZE ; i++ )
277 dvdcss->css.pi_title_key[i] = 0;
280 /* Test authentication success */
281 switch( CSSGetASF( dvdcss ) )
287 _dvdcss_debug( dvdcss, "successfully authenticated" );
291 _dvdcss_error( dvdcss, "no way to authenticate" );
296 _dvdcss_error( dvdcss, "CSS decryption is disabled in this module" );
298 #endif /* HAVE_CSS */
303 /*****************************************************************************
304 * CSSGetKey : get title key.
305 *****************************************************************************
306 * The DVD should have been opened and authenticated before.
307 *****************************************************************************/
308 int CSSGetKey( dvdcss_handle dvdcss )
312 * Title key cracking method from Ethan Hawke,
313 * with Frank A. Stevenson algorithm.
314 * Does not use any player key table and ioctls.
319 boolean_t b_encrypted;
320 boolean_t b_stop_scanning;
326 for( i = 0 ; i < KEY_SIZE ; i++ )
334 /* Position of the title on the disc */
335 i_pos = dvdcss->css.i_title_pos;
338 i_pos = dvdcss_seek( dvdcss, i_pos );
339 i_blocks_read = dvdcss_read( dvdcss, pi_buf, 1, DVDCSS_NOFLAGS );
341 /* PES_scrambling_control */
342 if( pi_buf[0x14] & 0x30 )
348 for( i = 2 ; i < 0x30 ; i++ )
350 for( j = i+1 ; ( j < 0x80 ) &&
351 ( pi_buf[0x7F - (j%i)] == pi_buf[0x7F-j] ) ; j++ );
353 if( j > i_best_plen )
361 if( ( i_best_plen > 20 ) && ( i_best_plen / i_best_p >= 2) )
363 i = CSSCracker( 0, &pi_buf[0x80],
364 &pi_buf[0x80 - ( i_best_plen / i_best_p) *i_best_p],
365 (dvd_key_t*)&pi_buf[0x54],
367 b_stop_scanning = ( i >= 0 );
371 i_pos += i_blocks_read;
372 } while( i_blocks_read == 0x1 && !b_stop_scanning);
376 memcpy( dvdcss->css.pi_title_key,
377 &pi_key, sizeof(dvd_key_t) );
378 _dvdcss_debug( dvdcss, "vts key initialized" );
384 _dvdcss_debug( dvdcss, "this file was _NOT_ encrypted!" );
391 _dvdcss_error( dvdcss, "css decryption unavailable" );
394 #endif /* HAVE_CSS */
397 /*****************************************************************************
398 * CSSDescrambleSector
399 *****************************************************************************
400 * sec : sector to descramble
401 * key : title key for this sector
402 *****************************************************************************/
403 int CSSDescrambleSector( dvd_key_t pi_key, u8* pi_sec )
406 unsigned int i_t1, i_t2, i_t3, i_t4, i_t5, i_t6;
407 u8* pi_end = pi_sec + 0x800;
409 /* PES_scrambling_control */
410 if( pi_sec[0x14] & 0x30)
412 i_t1 = ((pi_key)[0] ^ pi_sec[0x54]) | 0x100;
413 i_t2 = (pi_key)[1] ^ pi_sec[0x55];
414 i_t3 = (((pi_key)[2]) | ((pi_key)[3] << 8) |
415 ((pi_key)[4] << 16)) ^ ((pi_sec[0x56]) |
416 (pi_sec[0x57] << 8) | (pi_sec[0x58] << 16));
418 i_t3 = i_t3 * 2 + 8 - i_t4;
422 while( pi_sec != pi_end )
424 i_t4 = pi_css_tab2[i_t2] ^ pi_css_tab3[i_t1];
426 i_t1 = ( ( i_t1 & 1 ) << 8 ) ^ i_t4;
427 i_t4 = pi_css_tab5[i_t4];
428 i_t6 = ((((((( i_t3 >> 3 ) ^ i_t3 ) >> 1 ) ^
429 i_t3 ) >> 8 ) ^ i_t3 ) >> 5) & 0xff;
430 i_t3 = (i_t3 << 8 ) | i_t6;
431 i_t6 = pi_css_tab4[i_t6];
433 *pi_sec = pi_css_tab1[*pi_sec] ^( i_t5 & 0xff );
444 #endif /* HAVE_CSS */
449 /* Following functions are local */
451 /*****************************************************************************
452 * CSSGetASF : Get Authentification success flag
453 *****************************************************************************
456 * 0 if the device needs to be authenticated,
458 *****************************************************************************/
459 static int CSSGetASF( dvdcss_handle dvdcss )
464 for( i_agid = 0 ; i_agid < 4 ; i_agid++ )
466 if( ioctl_ReportASF( dvdcss->i_fd, &i_agid, &i_asf ) == 0 )
470 _dvdcss_debug( dvdcss, "GetASF authenticated" );
474 _dvdcss_debug( dvdcss, "GetASF not authenticated" );
481 /* The ioctl process has failed */
482 _dvdcss_error( dvdcss, "GetASF fatal error" );
486 /*****************************************************************************
487 * CSSCryptKey : shuffles bits and unencrypt keys.
488 *****************************************************************************
489 * Used during authentication and disc key negociation in CSSInit.
490 * i_key_type : 0->key1, 1->key2, 2->buskey.
491 * i_varient : between 0 and 31.
492 *****************************************************************************/
493 static void CSSCryptKey( int i_key_type, int i_varient,
494 u8 const * pi_challenge, u8* pi_key )
496 /* Permutation table for challenge */
497 u8 ppi_perm_challenge[3][10] =
498 { { 1, 3, 0, 7, 5, 2, 9, 6, 4, 8 },
499 { 6, 1, 9, 3, 8, 5, 7, 4, 0, 2 },
500 { 4, 0, 3, 5, 7, 2, 8, 6, 1, 9 } };
502 /* Permutation table for varient table for key2 and buskey */
503 u8 ppi_perm_varient[2][32] =
504 { { 0x0a, 0x08, 0x0e, 0x0c, 0x0b, 0x09, 0x0f, 0x0d,
505 0x1a, 0x18, 0x1e, 0x1c, 0x1b, 0x19, 0x1f, 0x1d,
506 0x02, 0x00, 0x06, 0x04, 0x03, 0x01, 0x07, 0x05,
507 0x12, 0x10, 0x16, 0x14, 0x13, 0x11, 0x17, 0x15 },
508 { 0x12, 0x1a, 0x16, 0x1e, 0x02, 0x0a, 0x06, 0x0e,
509 0x10, 0x18, 0x14, 0x1c, 0x00, 0x08, 0x04, 0x0c,
510 0x13, 0x1b, 0x17, 0x1f, 0x03, 0x0b, 0x07, 0x0f,
511 0x11, 0x19, 0x15, 0x1d, 0x01, 0x09, 0x05, 0x0d } };
514 { 0xB7, 0x74, 0x85, 0xD0, 0xCC, 0xDB, 0xCA, 0x73,
515 0x03, 0xFE, 0x31, 0x03, 0x52, 0xE0, 0xB7, 0x42,
516 0x63, 0x16, 0xF2, 0x2A, 0x79, 0x52, 0xFF, 0x1B,
517 0x7A, 0x11, 0xCA, 0x1A, 0x9B, 0x40, 0xAD, 0x01 };
519 /* The "secret" key */
520 u8 pi_secret[5] = { 0x55, 0xD6, 0xC4, 0xC5, 0x28 };
526 u8 i_lfsr0_o; /* 1 bit used */
527 u8 i_lfsr1_o; /* 1 bit used */
540 for (i = 9; i >= 0; --i)
541 pi_scratch[i] = pi_challenge[ppi_perm_challenge[i_key_type][i]];
543 i_css_varient = ( i_key_type == 0 ) ? i_varient :
544 ppi_perm_varient[i_key_type-1][i_varient];
547 * This encryption engine implements one of 32 variations
548 * one the same theme depending upon the choice in the
549 * varient parameter (0 - 31).
551 * The algorithm itself manipulates a 40 bit input into
553 * The parameter 'input' is 80 bits. It consists of
554 * the 40 bit input value that is to be encrypted followed
555 * by a 40 bit seed value for the pseudo random number
559 /* Feed the secret into the input values such that
560 * we alter the seed to the LFSR's used above, then
561 * generate the bits to play with.
563 for( i = 5 ; --i >= 0 ; )
565 pi_tmp1[i] = pi_scratch[5 + i] ^ pi_secret[i] ^ pi_crypt_tab2[i];
569 * We use two LFSR's (seeded from some of the input data bytes) to
570 * generate two streams of pseudo-random bits. These two bit streams
571 * are then combined by simply adding with carry to generate a final
572 * sequence of pseudo-random bits which is stored in the buffer that
573 * 'output' points to the end of - len is the size of this buffer.
575 * The first LFSR is of degree 25, and has a polynomial of:
576 * x^13 + x^5 + x^4 + x^1 + 1
578 * The second LSFR is of degree 17, and has a (primitive) polynomial of:
581 * I don't know if these polynomials are primitive modulo 2, and thus
582 * represent maximal-period LFSR's.
585 * Note that we take the output of each LFSR from the new shifted in
586 * bit, not the old shifted out bit. Thus for ease of use the LFSR's
587 * are implemented in bit reversed order.
591 /* In order to ensure that the LFSR works we need to ensure that the
592 * initial values are non-zero. Thus when we initialise them from
593 * the seed, we ensure that a bit is set.
595 i_lfsr0 = ( pi_tmp1[0] << 17 ) | ( pi_tmp1[1] << 9 ) |
596 (( pi_tmp1[2] & ~7 ) << 1 ) | 8 | ( pi_tmp1[2] & 7 );
597 i_lfsr1 = ( pi_tmp1[3] << 9 ) | 0x100 | pi_tmp1[4];
599 i_index = sizeof(pi_bits);
604 for( i_bit = 0, i_val = 0 ; i_bit < 8 ; ++i_bit )
607 i_lfsr0_o = ( ( i_lfsr0 >> 24 ) ^ ( i_lfsr0 >> 21 ) ^
608 ( i_lfsr0 >> 20 ) ^ ( i_lfsr0 >> 12 ) ) & 1;
609 i_lfsr0 = ( i_lfsr0 << 1 ) | i_lfsr0_o;
611 i_lfsr1_o = ( ( i_lfsr1 >> 16 ) ^ ( i_lfsr1 >> 2 ) ) & 1;
612 i_lfsr1 = ( i_lfsr1 << 1 ) | i_lfsr1_o;
614 i_combined = !i_lfsr1_o + i_carry + !i_lfsr0_o;
616 i_carry = ( i_combined >> 1 ) & 1;
617 i_val |= ( i_combined & 1 ) << i_bit;
620 pi_bits[--i_index] = i_val;
621 } while( i_index > 0 );
623 /* This term is used throughout the following to
624 * select one of 32 different variations on the
627 i_cse = pi_varients[i_css_varient] ^ pi_crypt_tab2[i_css_varient];
629 /* Now the actual blocks doing the encryption. Each
630 * of these works on 40 bits at a time and are quite
634 for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_scratch[i] )
636 i_index = pi_bits[25 + i] ^ pi_scratch[i];
637 i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
639 pi_tmp1[i] = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
641 pi_tmp1[4] ^= pi_tmp1[0];
643 for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp1[i] )
645 i_index = pi_bits[20 + i] ^ pi_tmp1[i];
646 i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
648 pi_tmp2[i] = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
650 pi_tmp2[4] ^= pi_tmp2[0];
652 for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp2[i] )
654 i_index = pi_bits[15 + i] ^ pi_tmp2[i];
655 i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
656 i_index = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
658 pi_tmp1[i] = pi_crypt_tab0[i_index] ^ pi_crypt_tab2[i_index];
660 pi_tmp1[4] ^= pi_tmp1[0];
662 for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp1[i] )
664 i_index = pi_bits[10 + i] ^ pi_tmp1[i];
665 i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
667 i_index = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
669 pi_tmp2[i] = pi_crypt_tab0[i_index] ^ pi_crypt_tab2[i_index];
671 pi_tmp2[4] ^= pi_tmp2[0];
673 for( i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp2[i] )
675 i_index = pi_bits[5 + i] ^ pi_tmp2[i];
676 i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
678 pi_tmp1[i] = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
680 pi_tmp1[4] ^= pi_tmp1[0];
682 for(i = 5, i_term = 0 ; --i >= 0 ; i_term = pi_tmp1[i] )
684 i_index = pi_bits[i] ^ pi_tmp1[i];
685 i_index = pi_crypt_tab1[i_index] ^ ~pi_crypt_tab2[i_index] ^ i_cse;
687 pi_key[i] = pi_crypt_tab2[i_index] ^ pi_crypt_tab3[i_index] ^ i_term;
693 /*****************************************************************************
694 * CSSCracker : title key decryption by cracking
695 *****************************************************************************
696 * This function is called by CSSGetKeys to find a key
697 *****************************************************************************/
698 static int CSSCracker( int i_start,
699 unsigned char * p_crypted,
700 unsigned char * p_decrypted,
701 dvd_key_t * p_sector_key,
704 unsigned char pi_buffer[10];
705 unsigned int i_t1, i_t2, i_t3, i_t4, i_t5, i_t6;
707 unsigned int i_candidate;
712 for( i = 0 ; i < 10 ; i++ )
714 pi_buffer[i] = pi_css_tab1[p_crypted[i]] ^ p_decrypted[i];
717 for( i_try = i_start ; i_try < 0x10000 ; i_try++ )
719 i_t1 = i_try >> 8 | 0x100;
721 i_t3 = 0; /* not needed */
724 /* iterate cipher 4 times to reconstruct LFSR2 */
725 for( i = 0 ; i < 4 ; i++ )
727 /* advance LFSR1 normaly */
728 i_t4 = pi_css_tab2[i_t2] ^ pi_css_tab3[i_t1];
730 i_t1 = ( ( i_t1 & 1 ) << 8 ) ^ i_t4;
731 i_t4 = pi_css_tab5[i_t4];
732 /* deduce i_t6 & i_t5 */
736 i_t6 = ( i_t6 + 0xff ) & 0x0ff;
744 i_t6 = pi_css_tab4[ i_t6 ];
745 /* feed / advance i_t3 / i_t5 */
746 i_t3 = ( i_t3 << 8 ) | i_t6;
752 /* iterate 6 more times to validate candidate key */
753 for( ; i < 10 ; i++ )
755 i_t4 = pi_css_tab2[i_t2] ^ pi_css_tab3[i_t1];
757 i_t1 = ( ( i_t1 & 1 ) << 8 ) ^ i_t4;
758 i_t4 = pi_css_tab5[i_t4];
759 i_t6 = ((((((( i_t3 >> 3 ) ^ i_t3 ) >> 1 ) ^
760 i_t3 ) >> 8 ) ^ i_t3 ) >> 5 ) & 0xff;
761 i_t3 = ( i_t3 << 8 ) | i_t6;
762 i_t6 = pi_css_tab4[i_t6];
764 if( ( i_t5 & 0xff ) != pi_buffer[i] )
774 /* Do 4 backwards steps of iterating t3 to deduce initial state */
776 for( i = 0 ; i < 4 ; i++ )
779 i_t3 = ( i_t3 >> 8 );
780 /* easy to code, and fast enough bruteforce
781 * search for byte shifted in */
782 for( j = 0 ; j < 256 ; j++ )
784 i_t3 = ( i_t3 & 0x1ffff) | ( j << 17 );
785 i_t6 = ((((((( i_t3 >> 3 ) ^ i_t3 ) >> 1 ) ^
786 i_t3 ) >> 8 ) ^ i_t3 ) >> 5 ) & 0xff;
794 i_t4 = ( i_t3 >> 1 ) - 4;
795 for( i_t5 = 0 ; i_t5 < 8; i_t5++ )
797 if( ( ( i_t4 + i_t5 ) * 2 + 8 - ( (i_t4 + i_t5 ) & 7 ) )
800 (*p_key)[0] = i_try>>8;
801 (*p_key)[1] = i_try & 0xFF;
802 (*p_key)[2] = ( ( i_t4 + i_t5 ) >> 0) & 0xFF;
803 (*p_key)[3] = ( ( i_t4 + i_t5 ) >> 8) & 0xFF;
804 (*p_key)[4] = ( ( i_t4 + i_t5 ) >> 16) & 0xFF;
813 (*p_key)[0] ^= (*p_sector_key)[0];
814 (*p_key)[1] ^= (*p_sector_key)[1];
815 (*p_key)[2] ^= (*p_sector_key)[2];
816 (*p_key)[3] ^= (*p_sector_key)[3];
817 (*p_key)[4] ^= (*p_sector_key)[4];
823 #endif /* HAVE_CSS */