DeCSS

/*
* 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

#!/usr/bin/perl

# DeCSS v 0.06 -- a utility for stripping Cascading Style Sheet (CSS)
# information from an HTML page

# Copyright 2000, Mr. Bad of Pigdog Journal (http://www.pigdog.org/).
# All Rights Reserved.

# This software is distributed under the Artistic License, which should have
# come with this file. Please distribute this software far and wide.
# The original version can always be found on the World Wide Web at:
#
# http://www.pigdog.org/decss/

# THIS PACKAGE IS PROVIDED »AS IS« AND WITHOUT ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
# WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.

use Getopt::Std;
use strict; # Choosy software use's strict!

my($USAGE) = <<»END_OF_USAGE«;
DeCSS 0.06: a utility to strip Cascading Style Sheets (CSS) tags
from HTML documents

USAGE: DeCSS [-h] [-i input file] [-o output file]

options:
-h print this help message
-i input file input file to strip (default: standard input)
-o output file place to put the output (default: standard output)

END_OF_USAGE

my(%options);
local(*IN, *OUT);

getopts(»hi:o:«, \%options);

if (exists $options{h}) {
print $USAGE;
exit(0);
}

if (exists $options{i}) {
open(IN, »<$options{i}«) or die »Can't open $options{i}: $!\n«;
} else {
open(IN, »<&STDIN«) or die »Can't open STDIN: $!\n«;
}

if (exists $options{o}) {
open(OUT, »>$options{o}«) or die »Can't open $options{o}: $!\n«;
} else {
open(OUT, »>&STDOUT«) or die »Can't open STDOUT: $!\n«;
}

decssify(*IN, *OUT);

close(IN);
close(OUT);

sub decssify {
local(*IN, *OUT) = @_;

# Yeah, like -you- never slurp in entire files at a time.

select(IN); undef $/;

my($content) = <IN>;

$content =~ s%<link.*?rel=\»stylesheet\«.*?>%%mg; # Strip stylesheet links
$content =~ s%<style>.*?</style>%%mg; # Strip <style> blocks
$content =~ s%style=\».*?\«%%mg; # Strip style attributes
$content =~ s%class=\».*?\«%%mg; # Strip class attributes
$content =~ s%id=\».*?\«%%mg; # Strip id attributes

print OUT $content;
}

__END__


=head1 NAME

DeCSS - A utility to strip Cascading Style Sheet (CSS) information from a Web page.

=head1 SYNOPSIS

DeCSS -i my_file.html -o my_file_no_css.html

=head1 DESCRIPTION

DeCSS is a utility program to strip Cascading Style Sheet (CSS)
information from a Web page. For a given input HTML file, it removes
the following type of HTML code:

=over 4

=item E<lt>styleE<gt> tags

=item E<lt>linkE<gt> tags that are for CSS stylesheets

=item C<class> attributes

=item C<style> attributes

=item C<id> attributes

=back

That's all it does. It has no relationship whatsoever to encryption,
copy protection, movies, software freedom, oppressive industry
cartels, Web site witch hunts, or any other bad things that could get
you in trouble. Please feel free to redistribute it as much as possible,
preferably on your Web site.

=head1 AUTHOR

Mister Bad <mr.bad@pigdog.org>

=head1 SEE ALSO

=over 4

=item W3 Cascading Style Sheets (CSS) site

http://www.w3.org/Style/CSS/

=back

=head1 VERSION HISTORY

=over 4

=item 0.06

Repackaged software, including mirroring utilities and a FAQ.

=item 0.05

Initial version.

=back

=cut

# Local Variables: #
# mode: perl #
# End: #