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/* vim: foldmethod=marker */
#include "des.h"
typedef struct des_block {
union {
uint64_t block;
struct {
uint32_t right;
uint32_t left;
};
};
} DES_Block;
static uint64_t base_des_crypt(const DES_Key *key, uint64_t blockIn, int keyStart, int keyStep);
static uint64_t IP(uint64_t block);
static uint64_t FP(uint64_t block);
static uint32_t ES(uint32_t x, uint64_t key);
static uint32_t P(uint64_t x);
static uint32_t F(uint32_t subblock, uint64_t subkey);
/* {{{ Lookup tables */
static const int ip_table[] = {
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6,
64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7,
};
static const int fp_table[] = {
40, 8, 48, 16, 56, 24, 64, 32,
39, 7, 47, 15, 55, 23, 63, 31,
38, 6, 46, 14, 54, 22, 62, 30,
37, 5, 45, 13, 53, 21, 61, 29,
36, 4, 44, 12, 52, 20, 60, 28,
35, 3, 43, 11, 51, 19, 59, 27,
34, 2, 42, 10, 50, 18, 58, 26,
33, 1, 41, 9, 49, 17, 57, 25,
};
static const int e_table[] = {
32, 1, 2, 3, 4, 5,
4, 5, 6, 7, 8, 9,
8, 9, 10, 11, 12, 13,
12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21,
20, 21, 22, 23, 24, 25,
24, 25, 26, 27, 28, 29,
28, 29, 30, 31, 32, 1,
};
static const int p_table[] = {
16, 7, 20, 21,
29, 12, 28, 17,
1, 15, 23, 26,
5, 18, 31, 10,
2, 8, 24, 14,
32, 27, 3, 9,
19, 13, 30, 6,
22, 11, 4, 25,
};
static const int sbox[][64] = {
/* S1 */
{ 14, 0, 4, 15, 13, 7, 1, 4, 2, 14, 15, 2, 11, 13, 8, 1,
3, 10, 10, 6, 6, 12, 12, 11, 5, 9, 9, 5, 0, 3, 7, 8,
4, 15, 1, 12, 14, 8, 8, 2, 13, 4, 6, 9, 2, 1, 11, 7,
15, 5, 12, 11, 9, 3, 7, 14, 3, 10, 10, 0, 5, 6, 0, 13, },
/* S2 */
{ 15, 3, 1, 13, 8, 4, 14, 7, 6, 15, 11, 2, 3, 8, 4, 14,
9, 12, 7, 0, 2, 1, 13, 10, 12, 6, 0, 9, 5, 11, 10, 5,
0, 13, 14, 8, 7, 10, 11, 1, 10, 3, 4, 15, 13, 4, 1, 2,
5, 11, 8, 6, 12, 7, 6, 12, 9, 0, 3, 5, 2, 14, 15, 9, },
/* S3 */
{ 10, 13, 0, 7, 9, 0, 14, 9, 6, 3, 3, 4, 15, 6, 5, 10,
1, 2, 13, 8, 12, 5, 7, 14, 11, 12, 4, 11, 2, 15, 8, 1,
13, 1, 6, 10, 4, 13, 9, 0, 8, 6, 15, 9, 3, 8, 0, 7,
11, 4, 1, 15, 2, 14, 12, 3, 5, 11, 10, 5, 14, 2, 7, 12, },
/* S4 */
{ 7, 13, 13, 8, 14, 11, 3, 5, 0, 6, 6, 15, 9, 0, 10, 3,
1, 4, 2, 7, 8, 2, 5, 12, 11, 1, 12, 10, 4, 14, 15, 9,
10, 3, 6, 15, 9, 0, 0, 6, 12, 10, 11, 1, 7, 13, 13, 8,
15, 9, 1, 4, 3, 5, 14, 11, 5, 12, 2, 7, 8, 2, 4, 14, },
/* S5 */
{ 2, 14, 12, 11, 4, 2, 1, 12, 7, 4, 10, 7, 11, 13, 6, 1,
8, 5, 5, 0, 3, 15, 15, 10, 13, 3, 0, 9, 14, 8, 9, 6,
4, 11, 2, 8, 1, 12, 11, 7, 10, 1, 13, 14, 7, 2, 8, 13,
15, 6, 9, 15, 12, 0, 5, 9, 6, 10, 3, 4, 0, 5, 14, 3, },
/* S6 */
{ 12, 10, 1, 15, 10, 4, 15, 2, 9, 7, 2, 12, 6, 9, 8, 5,
0, 6, 13, 1, 3, 13, 4, 14, 14, 0, 7, 11, 5, 3, 11, 8,
9, 4, 14, 3, 15, 2, 5, 12, 2, 9, 8, 5, 12, 15, 3, 10,
7, 11, 0, 14, 4, 1, 10, 7, 1, 6, 13, 0, 11, 8, 6, 13, },
/* S7 */
{ 4, 13, 11, 0, 2, 11, 14, 7, 15, 4, 0, 9, 8, 1, 13, 10,
3, 14, 12, 3, 9, 5, 7, 12, 5, 2, 10, 15, 6, 8, 1, 6,
1, 6, 4, 11, 11, 13, 13, 8, 12, 1, 3, 4, 7, 10, 14, 7,
10, 9, 15, 5, 6, 0, 8, 15, 0, 14, 5, 2, 9, 3, 2, 12, },
/* S8 */
{ 13, 1, 2, 15, 8, 13, 4, 8, 6, 10, 15, 3, 11, 7, 1, 4,
10, 12, 9, 5, 3, 6, 14, 11, 5, 0, 0, 14, 12, 9, 7, 2,
7, 2, 11, 1, 4, 14, 1, 7, 9, 4, 12, 10, 14, 8, 2, 13,
0, 15, 6, 12, 10, 9, 13, 0, 15, 3, 3, 5, 5, 6, 8, 11, },
};
/* }}} */
/* {{{ DES_Encrypt */
uint64_t DES_Encrypt(const DES_Key *key, uint64_t plain)
{
return FP(base_des_crypt(key, IP(plain), 0, +1));
}
/* }}} */
/* {{{ DES_Decrypt */
uint64_t DES_Decrypt(const DES_Key *key, uint64_t cipher)
{
return FP(base_des_crypt(key, IP(cipher), 15, -1));
}
/* }}} */
/* {{{ base_des_crypt */
static uint64_t base_des_crypt(const DES_Key *key, uint64_t blockIn, int keyStart, int keyStep)
{
DES_Block block;
int keyIndex = keyStart;
int i;
block.block = blockIn;
for (i = 0; i < 16; i++) {
block.left = F(block.right, key->schedule[keyIndex]) ^ block.left;
if (i != 15) {
/* swap subblocks */
block.left ^= block.right;
block.right ^= block.left;
block.left ^= block.right;
}
keyIndex += keyStep;
}
return block.block;
}
/* }}} */
/* {{{ IP */
static uint64_t IP(uint64_t block)
{
uint64_t ip = 0LL;
int i;
for (i = 0; i < 64; i++) {
ip <<= 1;
ip |= block >> (64 - ip_table[i]) & 0x1;
}
return ip;
}
/* }}} */
/* {{{ FP */
static uint64_t FP(uint64_t block)
{
uint64_t fp = 0LL;
int i;
for (i = 0; i < 64; i++) {
fp <<= 1;
fp |= block >> (64 - fp_table[i]) & 0x1;
}
return fp;
}
/* }}} */
/* {{{ ES */
/* combined E and S function */
static uint32_t ES(uint32_t x, uint64_t key)
{
uint64_t exp = (uint64_t)x << 47 | (uint64_t)x << 15 | x >> 17;
uint64_t mask = 0x3FLL << 42;
uint32_t ret = 0;
int i;
for (i = 0; i < 8; i++) {
ret <<= 4;
ret |= sbox[i][((exp ^ key) & mask) >> 42];
exp <<= 4;
key <<= 6;
}
return ret;
}
/* }}} */
/* {{{ P */
static uint32_t P(uint64_t x)
{
uint32_t ret = 0L;
int i;
for (i = 0; i < 32; i++) {
ret <<= 1;
ret |= x >> (32 - p_table[i]) & 0x1;
}
return ret;
}
/* }}} */
/* {{{ F */
/* The Feistel cipher function */
static uint32_t F(uint32_t subblock, uint64_t subkey)
{
return P(ES(subblock, subkey));
}
/* }}} */
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