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在写设计文档，突然被提起传输的数据最好还是加密！惶恐！你知道吗？单片机算DES，不是我疯掉就是单片机疯掉！
然后搜了下，感谢各位神仙~居然有这么多实现过的，下面是一例。
据说是已经测试通过的，最早为8位单片设计的，我也还没测，先找来放着，看着也心安。
//以下是des.c文件全部：
//密钥： B4 31 5B 86 9D 7D FA A2
//数据： 1F AD 61 A5 F7 19 77 14
//DES加密结果：4C 78 E9 1A F2 DA 9C D3
const uint8_t initial_tr[64] =
{
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,
56, 48, 40, 32, 24, 16, 8, 0,
58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6
};
const uint8_t final_tr[64] =
{
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,
32, 0, 40, 8, 48, 16, 56, 24
};
const uint8_t swap[64] =
{
33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48,
49, 50, 51, 52, 53, 54, 55, 56,
57, 58, 59, 60, 61, 62, 63, 64,
1, 2, 3, 4, 5, 6, 7, 8,
9, 10, 11, 12, 13, 14, 15, 16,
17, 18, 19, 20, 21, 22, 23, 24,
25, 26, 27, 28, 29, 30, 31, 32
};
const uint8_t key_tr1[56] =
{
56, 48, 40, 32, 24, 16, 8,
0, 57, 49, 41, 33, 25, 17,
9, 1, 58, 50, 42, 34, 26,
18, 10, 2, 59, 51, 43, 35,
62, 54, 46, 38, 30, 22, 14,
6, 61, 53, 45, 37, 29, 21,
13, 5, 60, 52, 44, 36, 28,
20, 12, 4, 27, 19, 11, 3
};
const uint8_t key_tr2[64] =
{
0, 0, 13, 4, 16, 10, 23, 0,
0, 0, 2, 9, 27, 14, 5, 20,
0, 0, 22, 7, 18, 11, 3, 25,
0, 0, 15, 1, 6, 26, 19, 12,
0, 0, 40, 54, 51, 30, 36, 46,
0, 0, 29, 47, 39, 50, 44, 32,
0, 0, 43, 52, 48, 38, 55, 33,
0, 0, 45, 31, 41, 49, 35, 28
};
const uint8_t etr[64] =
{
0, 0, 31, 4, 0, 1, 2, 3,
0, 0, 3, 8, 4, 5, 6, 7,
0, 0, 7, 12, 8, 9, 10, 11,
0, 0, 11, 16, 12, 13, 14, 15,
0, 0, 15, 20, 16, 17, 18, 19,
0, 0, 19, 24, 20, 21, 22, 23,
0, 0, 23, 28, 24, 25, 26, 27,
0, 0, 27, 0, 28, 29, 30, 31
};
const uint8_t ptr[32] =
{
31, 14, 39, 44, 60, 23, 55, 36,
4, 30, 46, 53, 12, 37, 62, 21,
5, 15, 47, 29, 63, 54, 6, 20,
38, 28, 61, 13, 45, 22, 7, 52
};
const uint8_t s[8][64] =
{
{
14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7,
0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8,
4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0,
15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13
},
{
15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10,
3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5,
0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15,
13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9
},
{
10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8,
13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1,
13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7,
1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12
},
{
7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15,
13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9,
10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4,
3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14
},
{
2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9,
14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6,
4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14,
11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3
},
{
12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11,
10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8,
9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6,
4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13
},
{
4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1,
13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6,
1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2,
6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12
},
{
13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7,
1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2,
7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8,
2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11
}
};
const uint8_t rots[16] =
{
1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
};
const uint8_t bit_msk[8] =
{
0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01
};
uint8_t DES_Encrypt_key[8];
uint8_t DES_Decrypt_key[8];
uint8_t sub_keys[16][8]; //sub_keys[16][8]
uint8_t main_key[8];
void des(uint8_t*, uint8_t*, uint8_t, uint8_t*);
void FLASH_Read_KEYS(uint8_t key_index);
static void transpose (uint8_t*, uint8_t*, const uint8_t*, uint8_t);
static void rotate_l (uint8_t*);
static void compute_subkeys (uint8_t*);
static void f (uint8_t*, uint8_t*, uint8_t*);
/************************************************************************/
/* */
/* Module title: des */
/* Module type: des mainrutine */
/* */
/* Author: YXH */
/* Date: 2012-07-13 */
/* */
/* Last changed by: YXH */
/* Date: 2012-07-13 */
/* */
/* Functional Description: Encipher and decipher 64 bits string */
/* according to a 64 bits key string */
/* The string format is shown below */
/* */
/* input parameter 1: pointer to 64 bits input string */
/* 2: pointer to 64 bits key string */
/* 3: boolean if false indicating enciphering */
/* if true dechiphering */
/* 4: pointer to a 64 bits output string */
/************************************************************************/
/* */
/* msb lsb */
/* bit bit */
/* +-- -- -- -- -- -- -- --+ */
/* addr !1st 8th! */
/* +-- -- -- -- -- -- -- --+ */
/* addr+1 !9th 16th! */
/* +-- -- -- -- -- -- -- --+ */
/* : : */
/* : : */
/* +-- -- -- -- -- -- -- --+ */
/* addr+7 !57th 64th! */
/* +-- -- -- -- -- -- -- --+ */
/* */
/************************************************************************/
void des(uint8_t *plain_strng, uint8_t *key, uint8_t d, uint8_t *ciph_strng)
{
uint8_t a_str[8], b_str[8], x_str[8];
uint8_t i, j, *pkey, temp;
for (i = 0; i < 8 ; ++i)
{
if (key[i] != main_key[i])
{
compute_subkeys(key);
i = 7;
}
}
transpose(plain_strng, a_str, initial_tr, 64);
for (i=1; i < 17; ++i)
{
for (j=0; j < 8; ++j){b_str[j] = a_str[j];}
if (!d) /*enchipher*/
pkey = &sub_keys[i-1][0];
else /*dechipher*/
pkey = &sub_keys[16-i][0];
for (j=0; j < 4; ++j){a_str[j] = b_str[j+4];}
f(pkey, a_str, x_str);
for (j=0; j < 4; ++j) {a_str[j+4] = b_str[j] ^ x_str[j];}
}
temp = a_str[0]; a_str[0] = a_str[4]; a_str[4] = temp;
temp = a_str[1]; a_str[1] = a_str[5]; a_str[5] = temp;
temp = a_str[2]; a_str[2] = a_str[6]; a_str[6] = temp;
temp = a_str[3]; a_str[3] = a_str[7]; a_str[7] = temp;
transpose(a_str, ciph_strng, final_tr, 64);
}
/************************************************************************/
/* */
/* Module title: transpose */
/* Module type: des subrutine */
/* */
/* Author: YXH */
/* Date: 2012-07-13 */
/* */
/* Last changed by: YXH */
/* Date: 2012-07-13 */
/* */
/* Functional Description: Permute n bits in a string, according */
/* to a table describing the new order. */
/* 0 < n <= 64 */
/* */
/* input parameter 1: pointer to first byte in input string */
/* 2: pointer to first byte in output string */
/* 3: pointer to table describing new order */
/* 4: number of bits to be permuted */
/************************************************************************/
void transpose(uint8_t *idata, uint8_t *odata, const uint8_t *tbl, uint8_t n)
{
const uint8_t *tab_adr;
int i, bi_idx;
tab_adr = &bit_msk[0];
i = 0;
do
{odata[i++] = 0;}
while (i < 8);
i = 0;
do
{
bi_idx = *tbl++;
if (idata[bi_idx>>3] & tab_adr[bi_idx & 7])
{
odata[i>>3] |= tab_adr[i & 7];
}
}
while (++i < n);
}
/************************************************************************/
/* */
/* Module title: rotate_l */
/* Module type: des subrutine */
/* */
/* Author: YXH */
/* Date: 2012-07-13 */
/* */
/* Last changed by: YXH */
/* Date: 2012-07-13 */
/* */
/* Functional Description: rotate 2 concatenated strings of 28 */
/* bits one position to the left. */
/* */
/* input parameter 1: pointer to first byte in key string */
/* */
/************************************************************************/
void rotate_l(uint8_t *key)
{
uint8_t str_x[8];
uint8_t i;
for (i=0; i < 8; ++i) str_x[i] = key[i];
for (i=0; i < 7; ++i)
{
key[i] = (key[i] << 1);
if ((i < 6) && ((str_x[i+1] & 128) == 128))
key[i] |= 1;
}
if (str_x[0] & 0x80 )
key[3] |= 0x10;
else
key[3] &= ~0x10;
if (str_x[3] & 0x08 )
key[6] |= 0x01;
else
key[6] &= ~0x01;
}
/************************************************************************/
/* */
/* Module title: compute_subkeys */
/* Module type: des subrutine */
/* */
/* Author: YXH */
/* Date: 2012-07-13 */
/* */
/* Last changed by: YXH */
/* Date: 2012-07-13 */
/* */
/* Functional Description: Computes the 16 sub keys for use in the */
/* DES algorithm */
/* */
/* input parameter 1: pointer to first byte in key string */
/* output : fills the array sub_keys[16][8] with */
/* sub keys and stores the input key in */
/* main_key[8] */
/************************************************************************/
void compute_subkeys(uint8_t *key)
{
uint8_t i, j, ikey[8], okey[8];
for (i=0; i < 8; ++i)
{
main_key[i] = key[i];
}
transpose(key, ikey, key_tr1, 56);
for (i=0; i < 16; ++i)
{
for (j=0; j < rots[i]; ++j) {rotate_l(ikey);}
transpose(ikey, okey, key_tr2, 64);
for (j=0; j < 8; ++j)
{ sub_keys[i][j] = okey[j];}
}
}
/************************************************************************/
/* */
/* Module title: f */
/* Module type: des subrutine */
/* */
/* Author: YXH */
/* Date: 2012-07-13 */
/* */
/* Last changed by: YXH */
/* Date: 2012-07-13 */
/* */
/* Functional Description: The chipher function */
/* */
/* input parameter 1: pointer to first byte in key string */
/* 2: pointer to a 32 bit input string */
/* 3: pointer to a 32 bit output string */
/************************************************************************/
void f(uint8_t *skey, uint8_t *a_str, uint8_t *x_str)
{
uint8_t e_str[8], y_str[8], z_str[8];
uint8_t k;
transpose(a_str, e_str, etr, 64);
for (k=0; k < 8; ++k)
{
y_str[k] = (e_str[k] ^ skey[k]) & 63;
z_str[k] = s[k] [y_str[k]];
}
transpose(z_str, x_str, ptr, 32);
}
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