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#include <unistd.h>
#include <fcntl.h>
#include "crypto.h"
#ifdef LTC_DES
static int urandom_fd;
static const unsigned char odd_parity[256] = {
1, 1, 2, 2, 4, 4, 7, 7, 8, 8, 11, 11, 13, 13, 14, 14,
16, 16, 19, 19, 21, 21, 22, 22, 25, 25, 26, 26, 28, 28, 31, 31,
32, 32, 35, 35, 37, 37, 38, 38, 41, 41, 42, 42, 44, 44, 47, 47,
49, 49, 50, 50, 52, 52, 55, 55, 56, 56, 59, 59, 61, 61, 62, 62,
64, 64, 67, 67, 69, 69, 70, 70, 73, 73, 74, 74, 76, 76, 79, 79,
81, 81, 82, 82, 84, 84, 87, 87, 88, 88, 91, 91, 93, 93, 94, 94,
97, 97, 98, 98,100,100,103,103,104,104,107,107,109,109,110,110,
112,112,115,115,117,117,118,118,121,121,122,122,124,124,127,127,
128,128,131,131,133,133,134,134,137,137,138,138,140,140,143,143,
145,145,146,146,148,148,151,151,152,152,155,155,157,157,158,158,
161,161,162,162,164,164,167,167,168,168,171,171,173,173,174,174,
176,176,179,179,181,181,182,182,185,185,186,186,188,188,191,191,
193,193,194,194,196,196,199,199,200,200,203,203,205,205,206,206,
208,208,211,211,213,213,214,214,217,217,218,218,220,220,223,223,
224,224,227,227,229,229,230,230,233,233,234,234,236,236,239,239,
241,241,242,242,244,244,247,247,248,248,251,251,253,253,254,254
};
void DES_set_odd_parity(DES_cblock *key)
{
unsigned int i;
for (i = 0; i < sizeof(DES_cblock); i++)
(*key)[i] = odd_parity[(*key)[i]];
}
int DES_check_key_parity(const_DES_cblock *key)
{
unsigned int i;
for (i = 0; i < sizeof(DES_cblock); i++) {
if ((*key)[i] != odd_parity[(*key)[i]])
return 0;
}
return 1;
}
static const DES_cblock weak_keys[] = {
/* weak keys */
{0x01,0x01,0x01,0x01,0x01,0x01,0x01,0x01},
{0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE,0xFE},
{0x1F,0x1F,0x1F,0x1F,0x0E,0x0E,0x0E,0x0E},
{0xE0,0xE0,0xE0,0xE0,0xF1,0xF1,0xF1,0xF1},
/* semi-weak keys */
{0x01,0xFE,0x01,0xFE,0x01,0xFE,0x01,0xFE},
{0xFE,0x01,0xFE,0x01,0xFE,0x01,0xFE,0x01},
{0x1F,0xE0,0x1F,0xE0,0x0E,0xF1,0x0E,0xF1},
{0xE0,0x1F,0xE0,0x1F,0xF1,0x0E,0xF1,0x0E},
{0x01,0xE0,0x01,0xE0,0x01,0xF1,0x01,0xF1},
{0xE0,0x01,0xE0,0x01,0xF1,0x01,0xF1,0x01},
{0x1F,0xFE,0x1F,0xFE,0x0E,0xFE,0x0E,0xFE},
{0xFE,0x1F,0xFE,0x1F,0xFE,0x0E,0xFE,0x0E},
{0x01,0x1F,0x01,0x1F,0x01,0x0E,0x01,0x0E},
{0x1F,0x01,0x1F,0x01,0x0E,0x01,0x0E,0x01},
{0xE0,0xFE,0xE0,0xFE,0xF1,0xFE,0xF1,0xFE},
{0xFE,0xE0,0xFE,0xE0,0xFE,0xF1,0xFE,0xF1}
};
int DES_is_weak_key(const_DES_cblock *key)
{
int i;
for (i = 0; i < sizeof(weak_keys); i++)
if (!memcmp(weak_keys[i], key, sizeof(DES_cblock)))
return 1;
return 0;
}
int DES_set_key_checked(const_DES_cblock *key, DES_key_schedule *schedule)
{
if (!DES_check_key_parity(key))
return -1;
if (DES_is_weak_key(key))
return -2;
return des_setup((const unsigned char *)key, 8, 0, schedule);
}
int DES_random_key(DES_cblock *ret)
{
while (1) {
read(urandom_fd, ret, sizeof(DES_cblock));
if (DES_is_weak_key(ret))
continue;
break;
}
DES_set_odd_parity(ret);
return 0;
}
void DES_ecb_encrypt(const_DES_cblock *input, DES_cblock *output, DES_key_schedule *ks, int enc)
{
if (enc == DES_ENCRYPT)
des_ecb_encrypt((const unsigned char *) input, (unsigned char *) output, ks);
else
if (enc == DES_DECRYPT)
des_ecb_decrypt((const unsigned char *) input, (unsigned char *) output, ks);
des_done(ks);
}
static void __attribute__((constructor)) init(void)
{
urandom_fd = open("/dev/urandom", O_RDONLY);
}
#endif
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