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/*
* Copyright (C) 1999 Derek Fawcus <derek@spider.com>
*
* This code may be used under the terms of Version 2 of the GPL,
* read the file COPYING for details.
*
*/
/*
* These routines do some reordering of the supplied data before
* calling engine() to do the main work.
*
* The reordering seems similar to that done by the initial stages of
* the DES algorithm, in that it looks like it's just been done to
* try and make software decoding slower. I'm not sure that it
* actually adds anything to the security.
*
* The nature of the shuffling is that the bits of the supplied
* parameter 'varient' are reorganised (and some inverted), and
* the bytes of the parameter 'challenge' are reorganised.
*
* The reorganisation in each routine is different, and the first
* (CryptKey1) does not bother of play with the 'varient' parameter.
*
* Since this code is only run once per disk change, I've made the
* code table driven in order to improve readability.
*
* Since these routines are so similar to each other, one could even
* abstract them all to one routine supplied a parameter determining
* the nature of the reordering it has to do.
*/
#include »css-auth.h«
typedef unsigned long u32;
static void engine(int varient, byte const *input, struct block *output);
void CryptKey1(int varient, byte const *challenge, struct block *key)
{
static byte perm_challenge[] = {1,3,0,7,5, 2,9,6,4,8};
byte scratch[10];
int i;
for (i = 9; i >= 0; --i)
scratch[i] = challenge[perm_challenge[i]];
engine(varient, scratch, key);
}
/* This shuffles the bits in varient to make perm_varient such that
* 4 -> !3
* 3 -> 4
* varient bits: 2 -> 0 perm_varient bits
* 1 -> 2
* 0 -> !1
*/
void CryptKey2(int varient, byte const *challenge, struct block *key)
{
static byte perm_challenge[] = {6,1,9,3,8, 5,7,4,0,2};
static byte perm_varient[] = {
0x0a, 0x08, 0x0e, 0x0c, 0x0b, 0x09, 0x0f, 0x0d,
0x1a, 0x18, 0x1e, 0x1c, 0x1b, 0x19, 0x1f, 0x1d,
0x02, 0x00, 0x06, 0x04, 0x03, 0x01, 0x07, 0x05,
0x12, 0x10, 0x16, 0x14, 0x13, 0x11, 0x17, 0x15};
byte scratch[10];
int i;
for (i = 9; i >= 0; --i)
scratch[i] = challenge[perm_challenge[i]];
engine(perm_varient[varient], scratch, key);
}
/* This shuffles the bits in varient to make perm_varient such that
* 4 -> 0
* 3 -> !1
* varient bits: 2 -> !4 perm_varient bits
* 1 -> 2
* 0 -> 3
*/
void CryptBusKey(int varient, byte const *challenge, struct block *key)
{
static byte perm_challenge[] = {4,0,3,5,7, 2,8,6,1,9};
static byte perm_varient[] = {
0x12, 0x1a, 0x16, 0x1e, 0x02, 0x0a, 0x06, 0x0e,
0x10, 0x18, 0x14, 0x1c, 0x00, 0x08, 0x04, 0x0c,
0x13, 0x1b, 0x17, 0x1f, 0x03, 0x0b, 0x07, 0x0f,
0x11, 0x19, 0x15, 0x1d, 0x01, 0x09, 0x05, 0x0d};
byte scratch[10];
int i;
for (i = 9; i >= 0; --i)
scratch[i] = challenge[perm_challenge[i]];
engine(perm_varient[varient], scratch, key);
}
/*
* We use two LFSR's (seeded from some of the input data bytes) to
* generate two streams of pseudo-random bits. These two bit streams
* are then combined by simply adding with carry to generate a final
* sequence of pseudo-random bits which is stored in the buffer that
* 'output' points to the end of - len is the size of this buffer.
*
* The first LFSR is of degree 25, and has a polynomial of:
* x^13 + x^5 + x^4 + x^1 + 1
*
* The second LSFR is of degree 17, and has a (primitive) polynomial of:
* x^15 + x^1 + 1
*
* I don't know if these polynomials are primitive modulo 2, and thus
* represent maximal-period LFSR's.
*
*
* Note that we take the output of each LFSR from the new shifted in
* bit, not the old shifted out bit. Thus for ease of use the LFSR's
* are implemented in bit reversed order.
*
*/
static void generate_bits(byte *output, int len, struct block const *s)
{
u32 lfsr0, lfsr1;
byte carry;
/* In order to ensure that the LFSR works we need to ensure that the
* initial values are non-zero. Thus when we initialise them from
* the seed, we ensure that a bit is set.
*/
lfsr0 = (s->b[0] << 17) | (s->b[1] << 9) | ((s->b[2] & ~7) << 1) | 8 | (s->b[2] & 7);
lfsr1 = (s->b[3] << 9) | 0x100 | s->b[4];
++output;
carry = 0;
do {
int bit;
byte val;
for (bit = 0, val = 0; bit < 8; ++bit) {
byte o_lfsr0, o_lfsr1; /* Actually only 1 bit each */
byte combined;
o_lfsr0 = ((lfsr0 >> 24) ^ (lfsr0 >> 21) ^ (lfsr0 >> 20) ^ (lfsr0 >> 12)) & 1;
lfsr0 = (lfsr0 << 1) | o_lfsr0;
o_lfsr1 = ((lfsr1 >> 16) ^ (lfsr1 >> 2)) & 1;
lfsr1 = (lfsr1 << 1) | o_lfsr1;
#define BIT0(x) ((x) & 1)
#define BIT1(x) (((x) >> 1) & 1)
combined = !o_lfsr1 + carry + !o_lfsr0;
carry = BIT1(combined);
val |= BIT0(combined) << bit;
}
*--output = val;
} while (--len > 0);
}
static byte Secret[];
static byte Varients[];
static byte Table0[];
static byte Table1[];
static byte Table2[];
static byte Table3[];
/*
* This encryption engine implements one of 32 variations
* one the same theme depending upon the choice in the
* varient parameter (0 - 31).
*
* The algorithm itself manipulates a 40 bit input into
* a 40 bit output.
* The parameter 'input' is 80 bits. It consists of
* the 40 bit input value that is to be encrypted followed
* by a 40 bit seed value for the pseudo random number
* generators.
*/
static void engine(int varient, byte const *input, struct block *output)
{
byte cse, term, index;
struct block temp1;
struct block temp2;
byte bits[30];
int i;
/* Feed the secret into the input values such that
* we alter the seed to the LFSR's used above, then
* generate the bits to play with.
*/
for (i = 5; --i >= 0; )
temp1.b[i] = input[5 + i] ^ Secret[i] ^ Table2[i];
generate_bits(&bits[29], sizeof bits, &temp1);
/* This term is used throughout the following to
* select one of 32 different variations on the
* algorithm.
*/
cse = Varients[varient] ^ Table2[varient];
/* Now the actual blocks doing the encryption. Each
* of these works on 40 bits at a time and are quite
* similar.
*/
for (i = 5, term = 0; --i >= 0; term = input[i]) {
index = bits[25 + i] ^ input[i];
index = Table1[index] ^ ~Table2[index] ^ cse;
temp1.b[i] = Table2[index] ^ Table3[index] ^ term;
}
temp1.b[4] ^= temp1.b[0];
for (i = 5, term = 0; --i >= 0; term = temp1.b[i]) {
index = bits[20 + i] ^ temp1.b[i];
index = Table1[index] ^ ~Table2[index] ^ cse;
temp2.b[i] = Table2[index] ^ Table3[index] ^ term;
}
temp2.b[4] ^= temp2.b[0];
for (i = 5, term = 0; --i >= 0; term = temp2.b[i]) {
index = bits[15 + i] ^ temp2.b[i];
index = Table1[index] ^ ~Table2[index] ^ cse;
index = Table2[index] ^ Table3[index] ^ term;
temp1.b[i] = Table0[index] ^ Table2[index];
}
temp1.b[4] ^= temp1.b[0];
for (i = 5, term = 0; --i >= 0; term = temp1.b[i]) {
index = bits[10 + i] ^ temp1.b[i];
index = Table1[index] ^ ~Table2[index] ^ cse;
index = Table2[index] ^ Table3[index] ^ term;
temp2.b[i] = Table0[index] ^ Table2[index];
}
temp2.b[4] ^= temp2.b[0];
for (i = 5, term = 0; --i >= 0; term = temp2.b[i]) {
index = bits[5 + i] ^ temp2.b[i];
index = Table1[index] ^ ~Table2[index] ^ cse;
temp1.b[i] = Table2[index] ^ Table3[index] ^ term;
}
temp1.b[4] ^= temp1.b[0];
for (i = 5, term = 0; --i >= 0; term = temp1.b[i]) {
index = bits[i] ^ temp1.b[i];
index = Table1[index] ^ ~Table2[index] ^ cse;
output->b[i] = Table2[index] ^ Table3[index] ^ term;
}
}
static byte Varients[] = {
0xB7, 0x74, 0x85, 0xD0, 0xCC, 0xDB, 0xCA, 0x73,
0x03, 0xFE, 0x31, 0x03, 0x52, 0xE0, 0xB7, 0x42,
0x63, 0x16, 0xF2, 0x2A, 0x79, 0x52, 0xFF, 0x1B,
0x7A, 0x11, 0xCA, 0x1A, 0x9B, 0x40, 0xAD, 0x01};
static byte Secret[] = {0x55, 0xD6, 0xC4, 0xC5, 0x28};
static byte Table0[] = {
0xB7, 0xF4, 0x82, 0x57, 0xDA, 0x4D, 0xDB, 0xE2,
0x2F, 0x52, 0x1A, 0xA8, 0x68, 0x5A, 0x8A, 0xFF,
0xFB, 0x0E, 0x6D, 0x35, 0xF7, 0x5C, 0x76, 0x12,
0xCE, 0x25, 0x79, 0x29, 0x39, 0x62, 0x08, 0x24,
0xA5, 0x85, 0x7B, 0x56, 0x01, 0x23, 0x68, 0xCF,
0x0A, 0xE2, 0x5A, 0xED, 0x3D, 0x59, 0xB0, 0xA9,
0xB0, 0x2C, 0xF2, 0xB8, 0xEF, 0x32, 0xA9, 0x40,
0x80, 0x71, 0xAF, 0x1E, 0xDE, 0x8F, 0x58, 0x88,
0xB8, 0x3A, 0xD0, 0xFC, 0xC4, 0x1E, 0xB5, 0xA0,
0xBB, 0x3B, 0x0F, 0x01, 0x7E, 0x1F, 0x9F, 0xD9,
0xAA, 0xB8, 0x3D, 0x9D, 0x74, 0x1E, 0x25, 0xDB,
0x37, 0x56, 0x8F, 0x16, 0xBA, 0x49, 0x2B, 0xAC,
0xD0, 0xBD, 0x95, 0x20, 0xBE, 0x7A, 0x28, 0xD0,
0x51, 0x64, 0x63, 0x1C, 0x7F, 0x66, 0x10, 0xBB,
0xC4, 0x56, 0x1A, 0x04, 0x6E, 0x0A, 0xEC, 0x9C,
0xD6, 0xE8, 0x9A, 0x7A, 0xCF, 0x8C, 0xDB, 0xB1,
0xEF, 0x71, 0xDE, 0x31, 0xFF, 0x54, 0x3E, 0x5E,
0x07, 0x69, 0x96, 0xB0, 0xCF, 0xDD, 0x9E, 0x47,
0xC7, 0x96, 0x8F, 0xE4, 0x2B, 0x59, 0xC6, 0xEE,
0xB9, 0x86, 0x9A, 0x64, 0x84, 0x72, 0xE2, 0x5B,
0xA2, 0x96, 0x58, 0x99, 0x50, 0x03, 0xF5, 0x38,
0x4D, 0x02, 0x7D, 0xE7, 0x7D, 0x75, 0xA7, 0xB8,
0x67, 0x87, 0x84, 0x3F, 0x1D, 0x11, 0xE5, 0xFC,
0x1E, 0xD3, 0x83, 0x16, 0xA5, 0x29, 0xF6, 0xC7,
0x15, 0x61, 0x29, 0x1A, 0x43, 0x4F, 0x9B, 0xAF,
0xC5, 0x87, 0x34, 0x6C, 0x0F, 0x3B, 0xA8, 0x1D,
0x45, 0x58, 0x25, 0xDC, 0xA8, 0xA3, 0x3B, 0xD1,
0x79, 0x1B, 0x48, 0xF2, 0xE9, 0x93, 0x1F, 0xFC,
0xDB, 0x2A, 0x90, 0xA9, 0x8A, 0x3D, 0x39, 0x18,
0xA3, 0x8E, 0x58, 0x6C, 0xE0, 0x12, 0xBB, 0x25,
0xCD, 0x71, 0x22, 0xA2, 0x64, 0xC6, 0xE7, 0xFB,
0xAD, 0x94, 0x77, 0x04, 0x9A, 0x39, 0xCF, 0x7C};
static byte Table1[] = {
0x8C, 0x47, 0xB0, 0xE1, 0xEB, 0xFC, 0xEB, 0x56,
0x10, 0xE5, 0x2C, 0x1A, 0x5D, 0xEF, 0xBE, 0x4F,
0x08, 0x75, 0x97, 0x4B, 0x0E, 0x25, 0x8E, 0x6E,
0x39, 0x5A, 0x87, 0x53, 0xC4, 0x1F, 0xF4, 0x5C,
0x4E, 0xE6, 0x99, 0x30, 0xE0, 0x42, 0x88, 0xAB,
0xE5, 0x85, 0xBC, 0x8F, 0xD8, 0x3C, 0x54, 0xC9,
0x53, 0x47, 0x18, 0xD6, 0x06, 0x5B, 0x41, 0x2C,
0x67, 0x1E, 0x41, 0x74, 0x33, 0xE2, 0xB4, 0xE0,
0x23, 0x29, 0x42, 0xEA, 0x55, 0x0F, 0x25, 0xB4,
0x24, 0x2C, 0x99, 0x13, 0xEB, 0x0A, 0x0B, 0xC9,
0xF9, 0x63, 0x67, 0x43, 0x2D, 0xC7, 0x7D, 0x07,
0x60, 0x89, 0xD1, 0xCC, 0xE7, 0x94, 0x77, 0x74,
0x9B, 0x7E, 0xD7, 0xE6, 0xFF, 0xBB, 0x68, 0x14,
0x1E, 0xA3, 0x25, 0xDE, 0x3A, 0xA3, 0x54, 0x7B,
0x87, 0x9D, 0x50, 0xCA, 0x27, 0xC3, 0xA4, 0x50,
0x91, 0x27, 0xD4, 0xB0, 0x82, 0x41, 0x97, 0x79,
0x94, 0x82, 0xAC, 0xC7, 0x8E, 0xA5, 0x4E, 0xAA,
0x78, 0x9E, 0xE0, 0x42, 0xBA, 0x28, 0xEA, 0xB7,
0x74, 0xAD, 0x35, 0xDA, 0x92, 0x60, 0x7E, 0xD2,
0x0E, 0xB9, 0x24, 0x5E, 0x39, 0x4F, 0x5E, 0x63,
0x09, 0xB5, 0xFA, 0xBF, 0xF1, 0x22, 0x55, 0x1C,
0xE2, 0x25, 0xDB, 0xC5, 0xD8, 0x50, 0x03, 0x98,
0xC4, 0xAC, 0x2E, 0x11, 0xB4, 0x38, 0x4D, 0xD0,
0xB9, 0xFC, 0x2D, 0x3C, 0x08, 0x04, 0x5A, 0xEF,
0xCE, 0x32, 0xFB, 0x4C, 0x92, 0x1E, 0x4B, 0xFB,
0x1A, 0xD0, 0xE2, 0x3E, 0xDA, 0x6E, 0x7C, 0x4D,
0x56, 0xC3, 0x3F, 0x42, 0xB1, 0x3A, 0x23, 0x4D,
0x6E, 0x84, 0x56, 0x68, 0xF4, 0x0E, 0x03, 0x64,
0xD0, 0xA9, 0x92, 0x2F, 0x8B, 0xBC, 0x39, 0x9C,
0xAC, 0x09, 0x5E, 0xEE, 0xE5, 0x97, 0xBF, 0xA5,
0xCE, 0xFA, 0x28, 0x2C, 0x6D, 0x4F, 0xEF, 0x77,
0xAA, 0x1B, 0x79, 0x8E, 0x97, 0xB4, 0xC3, 0xF4};
static byte Table2[] = {
0xB7, 0x75, 0x81, 0xD5, 0xDC, 0xCA, 0xDE, 0x66,
0x23, 0xDF, 0x15, 0x26, 0x62, 0xD1, 0x83, 0x77,
0xE3, 0x97, 0x76, 0xAF, 0xE9, 0xC3, 0x6B, 0x8E,
0xDA, 0xB0, 0x6E, 0xBF, 0x2B, 0xF1, 0x19, 0xB4,
0x95, 0x34, 0x48, 0xE4, 0x37, 0x94, 0x5D, 0x7B,
0x36, 0x5F, 0x65, 0x53, 0x07, 0xE2, 0x89, 0x11,
0x98, 0x85, 0xD9, 0x12, 0xC1, 0x9D, 0x84, 0xEC,
0xA4, 0xD4, 0x88, 0xB8, 0xFC, 0x2C, 0x79, 0x28,
0xD8, 0xDB, 0xB3, 0x1E, 0xA2, 0xF9, 0xD0, 0x44,
0xD7, 0xD6, 0x60, 0xEF, 0x14, 0xF4, 0xF6, 0x31,
0xD2, 0x41, 0x46, 0x67, 0x0A, 0xE1, 0x58, 0x27,
0x43, 0xA3, 0xF8, 0xE0, 0xC8, 0xBA, 0x5A, 0x5C,
0x80, 0x6C, 0xC6, 0xF2, 0xE8, 0xAD, 0x7D, 0x04,
0x0D, 0xB9, 0x3C, 0xC2, 0x25, 0xBD, 0x49, 0x63,
0x8C, 0x9F, 0x51, 0xCE, 0x20, 0xC5, 0xA1, 0x50,
0x92, 0x2D, 0xDD, 0xBC, 0x8D, 0x4F, 0x9A, 0x71,
0x2F, 0x30, 0x1D, 0x73, 0x39, 0x13, 0xFB, 0x1A,
0xCB, 0x24, 0x59, 0xFE, 0x05, 0x96, 0x57, 0x0F,
0x1F, 0xCF, 0x54, 0xBE, 0xF5, 0x06, 0x1B, 0xB2,
0x6D, 0xD3, 0x4D, 0x32, 0x56, 0x21, 0x33, 0x0B,
0x52, 0xE7, 0xAB, 0xEB, 0xA6, 0x74, 0x00, 0x4C,
0xB1, 0x7F, 0x82, 0x99, 0x87, 0x0E, 0x5E, 0xC0,
0x8F, 0xEE, 0x6F, 0x55, 0xF3, 0x7E, 0x08, 0x90,
0xFA, 0xB6, 0x64, 0x70, 0x47, 0x4A, 0x17, 0xA7,
0xB5, 0x40, 0x8A, 0x38, 0xE5, 0x68, 0x3E, 0x8B,
0x69, 0xAA, 0x9B, 0x42, 0xA5, 0x10, 0x01, 0x35,
0xFD, 0x61, 0x9E, 0xE6, 0x16, 0x9C, 0x86, 0xED,
0xCD, 0x2E, 0xFF, 0xC4, 0x5B, 0xA0, 0xAE, 0xCC,
0x4B, 0x3B, 0x03, 0xBB, 0x1C, 0x2A, 0xAC, 0x0C,
0x3F, 0x93, 0xC7, 0x72, 0x7A, 0x09, 0x22, 0x3D,
0x45, 0x78, 0xA9, 0xA8, 0xEA, 0xC9, 0x6A, 0xF7,
0x29, 0x91, 0xF0, 0x02, 0x18, 0x3A, 0x4E, 0x7C};
static byte Table3[] = {
0x73, 0x51, 0x95, 0xE1, 0x12, 0xE4, 0xC0, 0x58,
0xEE, 0xF2, 0x08, 0x1B, 0xA9, 0xFA, 0x98, 0x4C,
0xA7, 0x33, 0xE2, 0x1B, 0xA7, 0x6D, 0xF5, 0x30,
0x97, 0x1D, 0xF3, 0x02, 0x60, 0x5A, 0x82, 0x0F,
0x91, 0xD0, 0x9C, 0x10, 0x39, 0x7A, 0x83, 0x85,
0x3B, 0xB2, 0xB8, 0xAE, 0x0C, 0x09, 0x52, 0xEA,
0x1C, 0xE1, 0x8D, 0x66, 0x4F, 0xF3, 0xDA, 0x92,
0x29, 0xB9, 0xD5, 0xC5, 0x77, 0x47, 0x22, 0x53,
0x14, 0xF7, 0xAF, 0x22, 0x64, 0xDF, 0xC6, 0x72,
0x12, 0xF3, 0x75, 0xDA, 0xD7, 0xD7, 0xE5, 0x02,
0x9E, 0xED, 0xDA, 0xDB, 0x4C, 0x47, 0xCE, 0x91,
0x06, 0x06, 0x6D, 0x55, 0x8B, 0x19, 0xC9, 0xEF,
0x8C, 0x80, 0x1A, 0x0E, 0xEE, 0x4B, 0xAB, 0xF2,
0x08, 0x5C, 0xE9, 0x37, 0x26, 0x5E, 0x9A, 0x90,
0x00, 0xF3, 0x0D, 0xB2, 0xA6, 0xA3, 0xF7, 0x26,
0x17, 0x48, 0x88, 0xC9, 0x0E, 0x2C, 0xC9, 0x02,
0xE7, 0x18, 0x05, 0x4B, 0xF3, 0x39, 0xE1, 0x20,
0x02, 0x0D, 0x40, 0xC7, 0xCA, 0xB9, 0x48, 0x30,
0x57, 0x67, 0xCC, 0x06, 0xBF, 0xAC, 0x81, 0x08,
0x24, 0x7A, 0xD4, 0x8B, 0x19, 0x8E, 0xAC, 0xB4,
0x5A, 0x0F, 0x73, 0x13, 0xAC, 0x9E, 0xDA, 0xB6,
0xB8, 0x96, 0x5B, 0x60, 0x88, 0xE1, 0x81, 0x3F,
0x07, 0x86, 0x37, 0x2D, 0x79, 0x14, 0x52, 0xEA,
0x73, 0xDF, 0x3D, 0x09, 0xC8, 0x25, 0x48, 0xD8,
0x75, 0x60, 0x9A, 0x08, 0x27, 0x4A, 0x2C, 0xB9,
0xA8, 0x8B, 0x8A, 0x73, 0x62, 0x37, 0x16, 0x02,
0xBD, 0xC1, 0x0E, 0x56, 0x54, 0x3E, 0x14, 0x5F,
0x8C, 0x8F, 0x6E, 0x75, 0x1C, 0x07, 0x39, 0x7B,
0x4B, 0xDB, 0xD3, 0x4B, 0x1E, 0xC8, 0x7E, 0xFE,
0x3E, 0x72, 0x16, 0x83, 0x7D, 0xEE, 0xF5, 0xCA,
0xC5, 0x18, 0xF9, 0xD8, 0x68, 0xAB, 0x38, 0x85,
0xA8, 0xF0, 0xA1, 0x73, 0x9F, 0x5D, 0x19, 0x0B,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x33, 0x72, 0x39, 0x25, 0x67, 0x26, 0x6D, 0x71,
0x36, 0x77, 0x3C, 0x20, 0x62, 0x23, 0x68, 0x74,
0xC3, 0x82, 0xC9, 0x15, 0x57, 0x16, 0x5D, 0x81};
typedef unsigned char byte;
struct block {
byte b[5];
};
extern void CryptKey1(int varient, byte const *challenge, struct block *key);
extern void CryptKey2(int varient, byte const *challenge, struct block *key);
extern void CryptBusKey(int varient, byte const *challenge, struct block *key);
/*
* css-cat.c
*
* Copyright 1999 Derek Fawcus.
*
* Released under version 2 of the GPL.
*
* Decode selected sector types from a CSS encoded DVD to stdout. Use as a
* filter on the input to mpeg2player or ac3dec.
*
*/
#include <stdio.h>
#include <stdlib.h>
#if defined(__linux__)
# include <getopt.h>
#endif /* __linux__ */
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include »css-descramble.h«
static struct playkey pkey1a1 = {0x36b, {0x51,0x67,0x67,0xc5,0xe0}};
static struct playkey pkey2a1 = {0x762, {0x2c,0xb2,0xc1,0x09,0xee}};
static struct playkey pkey1b1 = {0x36b, {0x90,0xc1,0xd7,0x84,0x48}};
static struct playkey pkey1a2 = {0x2f3, {0x51,0x67,0x67,0xc5,0xe0}};
static struct playkey pkey2a2 = {0x730, {0x2c,0xb2,0xc1,0x09,0xee}};
static struct playkey pkey1b2 = {0x2f3, {0x90,0xc1,0xd7,0x84,0x48}};
static struct playkey pkey1a3 = {0x235, {0x51,0x67,0x67,0xc5,0xe0}};
static struct playkey pkey1b3 = {0x235, {0x90,0xc1,0xd7,0x84,0x48}};
static struct playkey pkey3a1 = {0x249, {0xb7,0x3f,0xd4,0xaa,0x14}}; /* DVD specific ? */
static struct playkey pkey4a1 = {0x028, {0x53,0xd4,0xf7,0xd9,0x8f}}; /* DVD specific ? */
static struct playkey *playkeys[] = {
&pkey1a1, &pkey2a1, &pkey1b1,
&pkey1a2, &pkey2a2, &pkey1b2,
&pkey1a3, &pkey1b3,
&pkey3a1, &pkey4a1,
NULL};
static unsigned char disk_key[2048];
static unsigned char title_key[5];
static unsigned char sector[2048];
unsigned long sectors = 0;
unsigned long crypted = 0;
unsigned long skipped = 0;
int do_all = 0;
int do_video = 0;
int do_ac3 = 0;
int do_mpg = 0;
int verbose = 0;
int keep_pack = 0;
int keep_pes = -1;
#define STCODE(p,a,b,c,d) ((p)[0] == a && (p)[1] == b && (p)[2] == c && (p)[3] == d)
static void un_css(int fdi, int fdo)
{
unsigned char *sp, *pes;
int writen, wr, peslen, hdrlen;
while (read(fdi, sector, 2048) == 2048) {
++sectors;
if (!STCODE(sector,0x00,0x00,0x01,0xba)) {
fputs(»Not Pack start code\n«, stderr);
++skipped; continue;
}
if (do_all)
goto write_it;
pes = sector + 14 + (sector[13] & 0x07);
if (STCODE(pes,0x00,0x00,0x01,0xbb)) {/* System Header Pack Layer */
peslen = (pes[0x04] << 8) + pes[0x05];
pes += peslen + 6;
}
if (pes[0x00] || pes[0x01] || pes[0x02] != 0x01 || pes[0x03] < 0xbc) {
++skipped; continue;
}
peslen = (pes[0x04] << 8) + pes[0x05];
hdrlen = pes[0x08] + 6 + 3;
if ((pes[0x03] & 0xf0) == 0xe0) {
if (do_video)
goto write_it;
} else if (do_mpg && pes[0x03] == (0xc0 | (do_mpg - 1))) { /* MPEG Audio */
goto write_it;
} else if (pes[0x03] == 0xbd) { /* AC3 Audio */
if (do_ac3) {
int audiotrack = do_ac3 - 1;
if (pes[hdrlen] == (0x80|(audiotrack & 7))) {
hdrlen += 4;
goto write_it;
}
}
} else
++skipped;
continue;
write_it:
if (sector[20] & 0x30) {
++crypted;
css_descramble(sector, title_key);
sector[20] &= 0x8f;
}
writen = 0;
if (keep_pack)
sp = sector, peslen = 2048;
else if (keep_pes)
sp = pes, peslen = 2048 - (pes - sector);
else
sp = pes + hdrlen, peslen -= hdrlen - 6;
do {
wr = write(fdo, sp, peslen - writen);
sp += wr;
writen += wr;
} while (wr > 0 && writen < peslen);
}
}
static void usage_exit(void)
{
fputs(»usage: css-cat [-t title-no] [-m mpeg-audio-no ] [-avPp12345678] vob_file\n«, stderr);
exit(2);
}
static char *title = »1«;
static int parse_args(int ac, char **av)
{
int c;
opterr = 0;
while (1)
switch((c = getopt(ac, av, »at:Ppvm:01234567«))) {
case 'a':
do_all = 1;
/* fall through */
case 'P':
keep_pack = 1;
break;
case 'p':
keep_pes = 1;
break;
case 't':
title = optarg;
break;
case 'v':
do_video = 1;
++keep_pes;
break;
case 'm':
if ((do_mpg = atoi(optarg)) < 1 || do_mpg > 32)
usage_exit();
++keep_pes;
break;
case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8':
do_ac3 = c - '0';
++keep_pes;
break;
case EOF:
goto got_args;
default:
usage_exit();
break;
}
got_args:
keep_pes = (keep_pes > 0) ? 1 : 0;
return optind;
}
int main(int ac, char **av)
{
int ai, fd;
char titlef[12];
if ((fd = open(»disk-key«, O_RDONLY)) == -1) {
perror(»can't open disk-key«);
exit(1);
}
if (read(fd, disk_key, 2048) != 2048) {
perror(»can't read disk-key«);
close(fd);
exit(1);
}
close(fd);
if ((ai = parse_args(ac, av)) >= ac)
usage_exit();
strcpy(titlef, »title«);
strcat(titlef, title);
strcat(titlef, »-key«);
if ((fd = open(titlef, O_RDONLY)) == -1) {
perror(»can't open title-key«);
exit(1);
}
if (read(fd, title_key, 5) != 5) {
perror(»can't read title-key«);
close(fd);
exit(1);
}
close(fd);
if (strcmp(av[ai], »-«) == 0)
fd = 0;
else if ((fd = open(av[ai], O_RDONLY)) == -1) {
fputs(»can't open VOB file «, stderr);
fputs(av[ai], stderr);
perror(»«);
exit(1);
}
if (!css_decrypttitlekey(title_key, disk_key, playkeys)) {
close(fd);
return 3;
}
un_css(fd, 1);
fprintf(stderr, »Total %lu, skipped %lu, crvid %lu\n«,
sectors, skipped, crypted);
close(fd);
return 0;
}
/*
* css_descramble.c
*
* Released under the version 2 of the GPL.
*
* Copyright 1999 Derek Fawcus
*
* This file contains functions to descramble CSS encrypted DVD content
*
*/
/*
* Still in progress: Remove the use of the bit_reverse[] table by recoding
* the generation of LFSR1. Finish combining this with
* the css authentication code.
*
*/
#include <stdio.h>
#include <string.h>
#include »css-descramble.h«
typedef unsigned char byte;
/*
*
* some tables used for descrambling sectors and/or decrypting title keys
*
*/
static byte csstab1[256]=
{
0x33,0x73,0x3b,0x26,0x63,0x23,0x6b,0x76,0x3e,0x7e,0x36,0x2b,0x6e,0x2e,0x66,0x7b,
0xd3,0x93,0xdb,0x06,0x43,0x03,0x4b,0x96,0xde,0x9e,0xd6,0x0b,0x4e,0x0e,0x46,0x9b,
0x57,0x17,0x5f,0x82,0xc7,0x87,0xcf,0x12,0x5a,0x1a,0x52,0x8f,0xca,0x8a,0xc2,0x1f,
0xd9,0x99,0xd1,0x00,0x49,0x09,0x41,0x90,0xd8,0x98,0xd0,0x01,0x48,0x08,0x40,0x91,
0x3d,0x7d,0x35,0x24,0x6d,0x2d,0x65,0x74,0x3c,0x7c,0x34,0x25,0x6c,0x2c,0x64,0x75,
0xdd,0x9d,0xd5,0x04,0x4d,0x0d,0x45,0x94,0xdc,0x9c,0xd4,0x05,0x4c,0x0c,0x44,0x95,
0x59,0x19,0x51,0x80,0xc9,0x89,0xc1,0x10,0x58,0x18,0x50,0x81,0xc8,0x88,0xc0,0x11,
0xd7,0x97,0xdf,0x02,0x47,0x07,0x4f,0x92,0xda,0x9a,0xd2,0x0f,0x4a,0x0a,0x42,0x9f,
0x53,0x13,0x5b,0x86,0xc3,0x83,0xcb,0x16,0x5e,0x1e,0x56,0x8b,0xce,0x8e,0xc6,0x1b,
0xb3,0xf3,0xbb,0xa6,0xe3,0xa3,0xeb,0xf6,0xbe,0xfe,0xb6,0xab,0xee,0xae,0xe6,0xfb,
0x37,0x77,0x3f,0x22,0x67,0x27,0x6f,0x72,0x3a,0x7a,0x32,0x2f,0x6a,0x2a,0x62,0x7f,
0xb9,0xf9,0xb1,0xa0,0xe9,0xa9,0xe1,0xf0,0xb8,0xf8,0xb0,0xa1,0xe8,0xa8,0xe0,0xf1,
0x5d,0x1d,0x55,0x84,0xcd,0x8d,0xc5,0x14,0x5c,0x1c,0x54,0x85,0xcc,0x8c,0xc4,0x15,
0xbd,0xfd,0xb5,0xa4,0xed,0xad,0xe5,0xf4,0xbc,0xfc,0xb4,0xa5,0xec,0xac,0xe4,0xf5,
0x39,0x79,0x31,0x20,0x69,0x29,0x61,0x70,0x38,0x78,0x30,0x21,0x68,0x28,0x60,0x71,
0xb7,0xf7,0xbf,0xa2,0xe7,0xa7,0xef,0xf2,0xba,0xfa,0xb2,0xaf,0xea,0xaa,0xe2,0xff
};
static byte lfsr1_bits0[256]=
{
0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07,0x09,0x08,0x0b,0x0a,0x0d,0x0c,0x0f,0x0e,
0x12,0x13,0x10,0x11,0x16,0x17,0x14,0x15,0x1b,0x1a,0x19,0x18,0x1f,0x1e,0x1d,0x1c,
0x24,0x25,0x26,0x27,0x20,0x21,0x22,0x23,0x2d,0x2c,0x2f,0x2e,0x29,0x28,0x2b,0x2a,
0x36,0x37,0x34,0x35,0x32,0x33,0x30,0x31,0x3f,0x3e,0x3d,0x3c,0x3b,0x3a,0x39,0x38,
0x49,0x48,0x4b,0x4a,0x4d,0x4c,0x4f,0x4e,0x40,0x41,0x42,0x43,0x44,0x45,0x46,0x47,
0x5b,0x5a,0x59,0x58,0x5f,0x5e,0x5d,0x5c,0x52,0x53,0x50,0x51,0x56,0x57,0x54,0x55,
0x6d,0x6c,0x6f,0x6e,0x69,0x68,0x6b,0x6a,0x64,0x65,0x66,0x67,0x60,0x61,0x62,0x63,
0x7f,0x7e,0x7d,0x7c,0x7b,0x7a,0x79,0x78,0x76,0x77,0x74,0x75,0x72,0x73,0x70,0x71,
0x92,0x93,0x90,0x91,0x96,0x97,0x94,0x95,0x9b,0x9a,0x99,0x98,0x9f,0x9e,0x9d,0x9c,
0x80,0x81,0x82,0x83,0x84,0x85,0x86,0x87,0x89,0x88,0x8b,0x8a,0x8d,0x8c,0x8f,0x8e,
0xb6,0xb7,0xb4,0xb5,0xb2,0xb3,0xb0,0xb1,0xbf,0xbe,0xbd,0xbc,0xbb,0xba,0xb9,0xb8,
0xa4,0xa5,0xa6,0xa7,0xa0,0xa1,0xa2,0xa3,0xad,0xac,0xaf,0xae,0xa9,0xa8,0xab,0xaa,
0xdb,0xda,0xd9,0xd8,0xdf,0xde,0xdd,0xdc,0xd2,0xd3,0xd0,0xd1,0xd6,0xd7,0xd4,0xd5,
0xc9,0xc8,0xcb,0xca,0xcd,0xcc,0xcf,0xce,0xc0,0xc1,0xc2,0xc3,0xc4,0xc5,0xc6,0xc7,
0xff,0xfe,0xfd,0xfc,0xfb,0xfa,0xf9,0xf8,0xf6,0xf7,0xf4,0xf5,0xf2,0xf3,0xf0,0xf1,
0xed,0xec,0xef,0xee,0xe9,0xe8,0xeb,0xea,0xe4,0xe5,0xe6,0xe7,0xe0,0xe1,0xe2,0xe3
};
static byte lfsr1_bits1[512]=
{
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,
0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff,0x00,0x24,0x49,0x6d,0x92,0xb6,0xdb,0xff
};
/* Reverse the order of the bits within a byte.
*/
static byte bit_reverse[256]=
{
0x00,0x80,0x40,0xc0,0x20,0xa0,0x60,0xe0,0x10,0x90,0x50,0xd0,0x30,0xb0,0x70,0xf0,
0x08,0x88,0x48,0xc8,0x28,0xa8,0x68,0xe8,0x18,0x98,0x58,0xd8,0x38,0xb8,0x78,0xf8,
0x04,0x84,0x44,0xc4,0x24,0xa4,0x64,0xe4,0x14,0x94,0x54,0xd4,0x34,0xb4,0x74,0xf4,
0x0c,0x8c,0x4c,0xcc,0x2c,0xac,0x6c,0xec,0x1c,0x9c,0x5c,0xdc,0x3c,0xbc,0x7c,0xfc,
0x02,0x82,0x42,0xc2,0x22,0xa2,0x62,0xe2,0x12,0x92,0x52,0xd2,0x32,0xb2,0x72,0xf2,
0x0a,0x8a,0x4a,0xca,0x2a,0xaa,0x6a,0xea,0x1a,0x9a,0x5a,0xda,0x3a,0xba,0x7a,0xfa,
0x06,0x86,0x46,0xc6,0x26,0xa6,0x66,0xe6,0x16,0x96,0x56,0xd6,0x36,0xb6,0x76,0xf6,
0x0e,0x8e,0x4e,0xce,0x2e,0xae,0x6e,0xee,0x1e,0x9e,0x5e,0xde,0x3e,0xbe,0x7e,0xfe,
0x01,0x81,0x41,0xc1,0x21,0xa1,0x61,0xe1,0x11,0x91,0x51,0xd1,0x31,0xb1,0x71,0xf1,
0x09,0x89,0x49,0xc9,0x29,0xa9,0x69,0xe9,0x19,0x99,0x59,0xd9,0x39,0xb9,0x79,0xf9,
0x05,0x85,0x45,0xc5,0x25,0xa5,0x65,0xe5,0x15,0x95,0x55,0xd5,0x35,0xb5,0x75,0xf5,
0x0d,0x8d,0x4d,0xcd,0x2d,0xad,0x6d,0xed,0x1d,0x9d,0x5d,0xdd,0x3d,0xbd,0x7d,0xfd,
0x03,0x83,0x43,0xc3,0x23,0xa3,0x63,0xe3,0x13,0x93,0x53,0xd3,0x33,0xb3,0x73,0xf3,
0x0b,0x8b,0x4b,0xcb,0x2b,0xab,0x6b,0xeb,0x1b,0x9b,0x5b,0xdb,0x3b,0xbb,0x7b,0xfb,
0x07,0x87,0x47,0xc7,0x27,0xa7,0x67,0xe7,0x17,0x97,0x57,0xd7,0x37,0xb7,0x77,0xf7,
0x0f,0x8f,0x4f,0xcf,0x2f,0xaf,0x6f,0xef,0x1f,0x9f,0x5f,0xdf,0x3f,0xbf,0x7f,0xff
};
/*
*
* this function is only used internally when decrypting title key
*
*/
static void css_titlekey(byte *key, byte *im, byte invert)
{
unsigned int lfsr1_lo,lfsr1_hi,lfsr0,combined;
byte o_lfsr0, o_lfsr1;
byte k[5];
int i;
lfsr1_lo = im[0] | 0x100;
lfsr1_hi = im[1];
lfsr0 = ((im[4] << 17) | (im[3] << 9) | (im[2] << 1)) + 8 - (im[2]&7);
lfsr0 = (bit_reverse[lfsr0&0xff]<<24) | (bit_reverse[(lfsr0>>8)&0xff] << 16)
| (bit_reverse[(lfsr0>>16)&0xff]<<8) | bit_reverse[(lfsr0>>24)&0xff];
combined = 0;
for (i = 0; i < 5; ++i) {
o_lfsr1 = lfsr1_bits0[lfsr1_hi] ^ lfsr1_bits1[lfsr1_lo];
lfsr1_hi = lfsr1_lo>>1;
lfsr1_lo = ((lfsr1_lo&1)<<8) ^ o_lfsr1;
o_lfsr1 = bit_reverse[o_lfsr1];
/*o_lfsr0 = (lfsr0>>7)^(lfsr0>>10)^(lfsr0>>11)^(lfsr0>>19);*/
o_lfsr0 = (((((((lfsr0>>8)^lfsr0)>>1)^lfsr0)>>3)^lfsr0)>>7);
lfsr0 = (lfsr0>>8)|(o_lfsr0<<24);
combined += (o_lfsr0 ^ invert) + o_lfsr1;
k[i] = combined & 0xff;
combined >>= 8;
}
key[4]=k[4]^csstab1[key[4]]^key[3];
key[3]=k[3]^csstab1[key[3]]^key[2];
key[2]=k[2]^csstab1[key[2]]^key[1];
key[1]=k[1]^csstab1[key[1]]^key[0];
key[0]=k[0]^csstab1[key[0]]^key[4];
key[4]=k[4]^csstab1[key[4]]^key[3];
key[3]=k[3]^csstab1[key[3]]^key[2];
key[2]=k[2]^csstab1[key[2]]^key[1];
key[1]=k[1]^csstab1[key[1]]^key[0];
key[0]=k[0]^csstab1[key[0]];
}
/*
*
* this function decrypts a title key with the specified disk key
*
* tkey: the unobfuscated title key (XORed with BusKey)
* dkey: the unobfuscated disk key (XORed with BusKey)
* 2048 bytes in length (though only 5 bytes are needed, see below)
* pkey: array of pointers to player keys and disk key offsets
*
*
* use the result returned in tkey with css_descramble
*
*/
int css_decrypttitlekey(byte *tkey, byte *dkey, struct playkey **pkey)
{
byte test[5], pretkey[5];
int i = 0;
for (; *pkey; ++pkey, ++i) {
memcpy(pretkey, dkey + (*pkey)->offset, 5);
css_titlekey(pretkey, (*pkey)->key, 0);
memcpy(test, dkey, 5);
css_titlekey(test, pretkey, 0);
if (memcmp(test, pretkey, 5) == 0) {
fprintf(stderr, »Using Key %d\n«, i+1);
break;
}
}
if (!*pkey) {
fprintf(stderr, »Shit - Need Key %d\n«, i+1);
return 0;
}
css_titlekey(tkey, pretkey, 0xff);
return 1;
}
/*
*
* this function does the actual descrambling
*
* sec: encrypted sector (2048 bytes)
* key: decrypted title key obtained from css_decrypttitlekey
*
*/
void css_descramble(byte *sec,byte *key)
{
unsigned int lfsr1_lo,lfsr1_hi,lfsr0,combined;
unsigned char o_lfsr0, o_lfsr1;
unsigned char *end = sec + 0x800;
#define SALTED(i) (key[i] ^ sec[0x54 + (i)])
lfsr1_lo = SALTED(0) | 0x100;
lfsr1_hi = SALTED(1);
lfsr0 = ((SALTED(4) << 17) | (SALTED(3) << 9) | (SALTED(2) << 1)) + 8 - (SALTED(2)&7);
lfsr0 = (bit_reverse[lfsr0&0xff]<<24) | (bit_reverse[(lfsr0>>8)&0xff] << 16)
| (bit_reverse[(lfsr0>>16)&0xff]<<8) | bit_reverse[(lfsr0>>24)&0xff];
sec+=0x80;
combined = 0;
while (sec != end) {
o_lfsr1 = lfsr1_bits0[lfsr1_hi] ^ lfsr1_bits1[lfsr1_lo];
lfsr1_hi = lfsr1_lo>>1;
lfsr1_lo = ((lfsr1_lo&1)<<8) ^ o_lfsr1;
o_lfsr1 = bit_reverse[o_lfsr1];
/*o_lfsr0 = (lfsr0>>7)^(lfsr0>>10)^(lfsr0>>11)^(lfsr0>>19);*/
o_lfsr0 = (((((((lfsr0>>8)^lfsr0)>>1)^lfsr0)>>3)^lfsr0)>>7);
lfsr0 = (lfsr0>>8)|(o_lfsr0<<24);
combined += o_lfsr0 + (byte)~o_lfsr1;
*sec++ = csstab1[*sec] ^ (combined&0xff);
combined >>= 8;
}
}
#ifndef __css_descramble_h_
#define __css_descramble_h_
struct playkey {
int offset;
unsigned char key[5];
};
extern int css_decrypttitlekey(unsigned char *tkey, unsigned char *dkey, struct playkey **pkey);
extern void css_descramble(unsigned char *sec,unsigned char *key);
#endif
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