Несанкционированный доступ к терминалам серверов с операционными системами семейства UNIX. На примере octopus.stu.lipetsk.ru
nbsp; do {
DES_bs_all.K[bit++] |= (value & 1) << index;
} while (value >>= 1);
}
}
void DES_bs_crypt(int count)
{
register int bit;
register ARCH_WORD R, L;
memset(DES_bs_all.B, 0, sizeof(DES_bs_all.B));
do {
DES_bs_body();
if (!--count) break;
for (bit = 0; bit < 32; bit++) {
R = DES_bs_all.B[bit];
L = DES_bs_all.B[bit + 32];
DES_bs_all.B[bit + 32] = R;
DES_bs_all.B[bit] = L;
}
} while (1);
}
ARCH_WORD *DES_bs_get_binary(char *ciphertext)
{
static ARCH_WORD out[64];
ARCH_WORD *raw;
int bit;
int index, shift;
int value;
raw = DES_raw_get_binary(ciphertext);
out[1] = out[0] = 0;
for (bit = 0; bit < 64; bit++) {
index = bit >> 4;
/* Swap L and R here instead of doing it one more time in DES_bs_crypt() */
index ^= 2;
/* Calculate the number of one of the 16 data bits in raw[index] */
shift = ((bit & 0xC) << 1) + (bit & 3) + 1;
/* Get the bit */
value = (raw[index] >> shift) & 1;
if (DES_bs_mem_saving)
/* Memory saving: pack the bits into two words */
out[bit >> 5] |= value << (bit & 0x1F);
else
/* We either set or clear all the bits in every word */
out[bit] = value ? ~(ARCH_WORD)0 : 0;
}
return out;
}
int DES_bs_binary_hash(ARCH_WORD *binary, int count)
{
int bit, result;
if (DES_bs_mem_saving)
return (int)*binary & ((1 << count) - 1);
result = 0;
for (bit = 0; bit < count; bit++)
if (binary[bit]) result |= 1 << bit;
return result;
}
int DES_bs_get_hash(int index, int count)
{
register int bit, result;
register ARCH_WORD mask;
mask = (ARCH_WORD)1 << index;
result = 0;
for (bit = 0; bit < count; bit++)
if (DES_bs_all.B[bit] & mask) result |= 1 << bit;
return result;
}
/*
* The trick I used here allows to compare one ciphertext against all the
* DES_bs_crypt() outputs in just O(log2(ARCH_BITS)) operations.
*/
int DES_bs_cmp_all(ARCH_WORD *binary, int count)
{
register int bit;
register ARCH_WORD mask;
mask = 0;
if (DES_bs_mem_saving)
for (bit = 0; bit < ((count < 32) ? count : 32); bit++) {
mask |= DES_bs_all.B[bit] ^
((binary[0] & (1 << bit)) ? ~(ARCH_WORD)0 : 0);
if (mask == ~(ARCH_WORD)0) return 0;
}
else
for (bit = 0; bit < count; bit++) {
mask |= DES_bs_all.B[bit] ^ binary[bit];
if (mask == ~(ARCH_WORD)0) return 0;
}
return 1;
}
int DES_bs_cmp_one(ARCH_WORD *binary, int count, int index)
{
register int bit;
register ARCH_WORD mask;
if (DES_bs_mem_saving) {
for (bit = 0; bit < count; bit++)
if (((DES_bs_all.B[bit] >> index) ^
(binary[bit >> 5] >> (bit & 0x1F))) & 1) return 0;
return 1;
}
mask = (ARCH_WORD)1 << index;
for (bit = 0; bit < count; bit++)
if ((DES_bs_all.B[bit] ^ binary[bit]) & mask) return 0;
return 1;
}
-----------------------
User name
0H. ?0@>;L
>;=>5 8
| |  скачать работу |
Несанкционированный доступ к терминалам серверов с операционными системами семейства UNIX. На примере octopus.stu.lipetsk.ru | 
