void cps2_decrypt(const u32 *master_key)
{
u16 *rom = (u16 *)memory_region_cpu1;
int length = memory_length_cpu1;
u16 *dec = (u16 *)memory_region_user1;
int upper_limit = memory_length_user1;
int i;
u32 key1[4];
// expand master key to 1st FN 96-bit key
expand_1st_key(key1, master_key);
// add extra bits for s-boxes with less than 6 inputs
key1[0] ^= BIT(key1[0], 1) << 4;
key1[0] ^= BIT(key1[0], 2) << 5;
key1[0] ^= BIT(key1[0], 8) << 11;
key1[1] ^= BIT(key1[1], 0) << 5;
key1[1] ^= BIT(key1[1], 8) << 11;
key1[2] ^= BIT(key1[2], 1) << 5;
key1[2] ^= BIT(key1[2], 8) << 11;
for (i = 0; i < 0x10000; ++i)
{
int a;
u16 seed;
u32 subkey[2];
u32 key2[4];
if ((i & 0x1fff) == 0)
{
msg_printf("Decrypting... %d%%\n", i*100/0x10000);
}
// pass the address through FN1
seed = feistel(i, fn1_groupA, fn1_groupB,
fn1_r1_boxes, fn1_r2_boxes, fn1_r3_boxes, fn1_r4_boxes,
key1[0], key1[1], key1[2], key1[3]);
// expand the result to 64-bit
expand_subkey(subkey, seed);
// XOR with the master key
subkey[0] ^= master_key[0];
subkey[1] ^= master_key[1];
// expand key to 2nd FN 96-bit key
expand_2nd_key(key2, subkey);
// add extra bits for s-boxes with less than 6 inputs
key2[0] ^= BIT(key2[0], 0) << 5;
key2[0] ^= BIT(key2[0], 6) << 11;
key2[1] ^= BIT(key2[1], 0) << 5;
key2[1] ^= BIT(key2[1], 1) << 4;
key2[2] ^= BIT(key2[2], 2) << 5;
key2[2] ^= BIT(key2[2], 3) << 4;
key2[2] ^= BIT(key2[2], 7) << 11;
key2[3] ^= BIT(key2[3], 1) << 5;
// decrypt the opcodes
for (a = i; a < length/2 && a < upper_limit/2; a += 0x10000)
{
dec[a] = feistel(rom[a], fn2_groupA, fn2_groupB,
fn2_r1_boxes, fn2_r2_boxes, fn2_r3_boxes, fn2_r4_boxes,
key2[0], key2[1], key2[2], key2[3]);
}
// copy the unencrypted part (not really needed)
/*
while (a < length/2)
{
dec[a] = rom[a];
a += 0x10000;
}
*/
}
msg_printf("Decrypting... Complete\n");
//m68000_set_encrypted_range(0x000000, length - 1, dec);
}
int main (int argc, char *argv[])
{
int i = 0;
char c;
unsigned long data = 4037734570;
unsigned long subkey[2] = {453177088, 4235227648};
char input[] = "11110000101010101111000010101010";
char output[] = "00100011010010101010100110111011";
char subkey_string[] = "000110110000001011101111111111000111000001110010";
printf("\x1b[1;35mtestfeistel\x1b[0m\n\n");
printf("Bits before feistel:\t ");
for (i = 0; i < 32; i++) {
if (bitmasks[i + 1] & data) {
printf("1");
} else {
printf("0");
}
if (((i + 1) % 4) == 0) {
printf(" ");
}
}
printf("\nBits should be:\t\t ");
for (i = 0; i < 32; i++) {
printf("%c", input[i]);
if (((i + 1) % 4) == 0) {
printf(" ");
}
}
printf("\n");
printf("Subkey: \t\t");
for (i = 0; i < 48; i++) {
printf("%c", subkey_string[i]);
if (((i + 1) % 6) == 0) {
printf(" ");
}
}
printf("\n");
data = feistel(&data, (unsigned long *)subkey);
printf("After feistel:\t\t ");
for (i = 0; i < 32; i++) {
if (bitmasks[i + 1] & data) {
printf("1");
} else {
printf("0");
}
if (((i + 1) % 4) == 0) {
printf(" ");
}
}
printf("\n");
printf("Should be: \t\t ");
for (i = 0; i < 32; i++) {
printf("%c", output[i]);
if (((i + 1) % 4) == 0) {
printf(" ");
}
if (bitmasks[i + 1] & data) {
c = '1';
} else {
c = '0';
}
if (c != output[i]) {
printf("\n\x1b[1;31mFAILED!\x1b[0m\n");
goto QUIT;
}
}
printf("\n");
printf("\n\x1b[1;35m\\testfeistel\x1b[0m\n");
printf("\n\x1b[1;34mPASSED!\x1b[0m\n\n");
QUIT:
return 0;
}
static void cps2_decrypt(const UINT32 *master_key, unsigned int upper_limit)
{
UINT16 *rom = (UINT16 *)memory_region(REGION_CPU1);
int length = memory_region_length(REGION_CPU1);
UINT16 *dec = auto_malloc(length);
int i;
UINT32 key1[4];
// expand master key to 1st FN 96-bit key
expand_1st_key(key1, master_key);
// add extra bits for s-boxes with less than 6 inputs
key1[0] ^= BIT(key1[0], 1) << 4;
key1[0] ^= BIT(key1[0], 2) << 5;
key1[0] ^= BIT(key1[0], 8) << 11;
key1[1] ^= BIT(key1[1], 0) << 5;
key1[1] ^= BIT(key1[1], 8) << 11;
key1[2] ^= BIT(key1[2], 1) << 5;
key1[2] ^= BIT(key1[2], 8) << 11;
for (i = 0; i < 0x10000; ++i)
{
int a;
UINT16 seed;
UINT32 subkey[2];
UINT32 key2[4];
if ((i & 0xff) == 0)
{
char loadingMessage[256]; // for displaying with UI
sprintf(loadingMessage, "Decrypting %d%%", i*100/0x10000);
ui_set_startup_text(loadingMessage,FALSE);
}
// pass the address through FN1
seed = feistel(i, fn1_groupA, fn1_groupB,
fn1_r1_boxes, fn1_r2_boxes, fn1_r3_boxes, fn1_r4_boxes,
key1[0], key1[1], key1[2], key1[3]);
// expand the result to 64-bit
expand_subkey(subkey, seed);
// XOR with the master key
subkey[0] ^= master_key[0];
subkey[1] ^= master_key[1];
// expand key to 2nd FN 96-bit key
expand_2nd_key(key2, subkey);
// add extra bits for s-boxes with less than 6 inputs
key2[0] ^= BIT(key2[0], 0) << 5;
key2[0] ^= BIT(key2[0], 6) << 11;
key2[1] ^= BIT(key2[1], 0) << 5;
key2[1] ^= BIT(key2[1], 1) << 4;
key2[2] ^= BIT(key2[2], 2) << 5;
key2[2] ^= BIT(key2[2], 3) << 4;
key2[2] ^= BIT(key2[2], 7) << 11;
key2[3] ^= BIT(key2[3], 1) << 5;
// decrypt the opcodes
for (a = i; a < length/2 && a < upper_limit/2; a += 0x10000)
{
dec[a] = feistel(rom[a], fn2_groupA, fn2_groupB,
fn2_r1_boxes, fn2_r2_boxes, fn2_r3_boxes, fn2_r4_boxes,
key2[0], key2[1], key2[2], key2[3]);
}
// copy the unencrypted part (not really needed)
while (a < length/2)
{
dec[a] = rom[a];
a += 0x10000;
}
}
memory_set_decrypted_region(0, 0x000000, length - 1, dec);
m68k_set_encrypted_opcode_range(0,0,length);
#if 0
{
FILE *f;
f = fopen("d:/s.rom","wb");
fwrite(rom,1,0x100000,f);
fclose(f);
f = fopen("d:/s.dec","wb");
fwrite(dec,1,0x100000,f);
fclose(f);
}
#endif
}
