本文分享了一种基于STM32平台的DES加密算法C语言实现，包括完整的源代码及测试示例。该实现适用于单片机应用中数据加密的需求，并提供了一个三重DES（3DES）加密解密的示例。
基于单片机的DES加密解密算法C源码
有一STM32项目需要用到DES算法，从网上找了很多资料什么的，看的似是而非的，只好找以前一个ASCOM的基于8位机，16位机的IC卡电话机的DES源码移植过来使用，测试通过后公布，方便大家借鉴使用。
//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
源码：
一个高手的代码：
https://blog.youkuaiyun.com/SuGuolin/article/details/77887590
如下：
#include <string.h>
#include <stdint.h> // for 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: Encjipher 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 f(uint8_t *skey, uint8_t *a_str, uint8_t *x_str);
void compute_subkeys(uint8_t *key);
void transpose(uint8_t *idata, uint8_t *odata, const uint8_t *tbl, uint8_t n);
void transpose_debug(uint8_t *idata, uint8_t *odata, const uint8_t *tbl, uint8_t n);
void printBuf(unsigned char *s, unsigned char *buf, int cnt, int num)
{
int i;
printf("%12s ", s);
for (i = 0; i < cnt; i++)
{
printf("%02x ", *(buf + i));
if ((i + 1) % num == 0){
printf("\r\n");
}
}
printf("\r\n");
}
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 char rots[16] =
{
1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
};
const char 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 *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);
}
void des_debug(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;
}
}
printf("Hello:\r\n");
transpose_debug(plain_strng, a_str, initial_tr, 64);
printBuf("a_str:", a_str, 8, 32);
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 = (uint8_t *)&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);
}
void transpose_debug(uint8_t *idata, uint8_t *odata, const uint8_t *tbl, uint8_t n)
{
const uint8_t *tab_adr;
int i, bi_idx;
tab_adr = (uint8_t *)&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];
printf("1--%d,%d,%x\r\n", bi_idx, bi_idx & 7, (unsigned char)idata[bi_idx >> 3]);
}
else{
printf("0--%d,%d,%x\r\n", bi_idx, bi_idx & 7, (unsigned char)idata[bi_idx >> 3]);
}
if ((i + 1) % 16 == 0){
printf("\r\n");
}
} 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) //计算子匙
{
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: DES3 */
/* Module type: 3des */
/* */
/* Author: HRX */
/* Date: 2017-01-12 */
/* */
/* Last changed by: HRX */
/* Date: 2017-01-12 */
/* */
/* Functional Description: The chipher function */
/* */
/* input parameter 1: 加密(解密)的数据 */
/* 2: 加密(解密)的数据长度 */
/* 3: 16字节密钥 */
/* 4: 模式(0:加密 1:解密) */
/* 5: 加密(解密)后的数? */
/************************************************************************/
void DES3(char *input, uint8_t inputlen, char* key, uint8_t mode, char * ouput)
{
uint8_t number, i;
char out[8], among[8], among1[8], in[8], key1[8], key2[8];
number = inputlen / 8;
if (inputlen % 8 != 0)
number++;
memcpy(key1, key, 8);
memcpy(key2, &key[8], 8);
for (i = 0; i<number; i++)
{
//每8字节做一次3DES
memcpy(in, &input[i * 8], 8);
if (mode == 0) //加密模式
{
des((uint8_t *)&in, (uint8_t *)key1, 0, (uint8_t *)among); //密钥1 DES加密
des((uint8_t *)&among, (uint8_t *)key2, 1, (uint8_t *)among1); //密钥2 解密
des((uint8_t *)&among1, (uint8_t *)key1, 0, (uint8_t *)out); //密钥1 DES加密
}
else if (mode == 1) //解密模式
{
des((uint8_t *)&in, (uint8_t *)key1, 1, (uint8_t *)among); //密钥1 DES解密
des((uint8_t *)&among, (uint8_t *)key2, 0, (uint8_t *)among1); //密钥2 DES加密
des((uint8_t *)&among1, (uint8_t *)key1, 1, (uint8_t *)out); //密钥1 DES解密
}
memcpy(&ouput[i * 8], out, 8);
}
}
/************************************************************************/
/* */
/* 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);
}
void Test_DES3(void)
{
uint8_t KEY[16] = {
0x58, 0x24, 0x4B, 0x65, 0x98,
0x1A, 0x2E, 0x85, 0x60, 0x77,
0x39, 0x65, 0x88, 0x73, 0x4F, 0x38
};
uint8_t input[16] = {
0x11, 0x09, 0x06, 0x09, 0x24, 0x35,
0x00, 0x01, 0x70, 0x71, 0x90, 0x14,
0x99, 0x00, 0x00, 0x00
};
// uint8_t input[8]={0x41,0x42,0x43,0x44,0x45,0x30,0x30,0x30};
uint8_t output[16] = { 0 };
uint8_t output2[16] = { 0 };
int i;
printf("\r\ninput:\r\n");
for (i = 0; i < sizeof(input); i++)
{
printf("%02x", *(input + i));
}
printf("\n");
// des((uint8_t *)&input,(uint8_t *)KEY,0,(uint8_t *)output);
// for (i = 0; i < sizeof(output); i++)
// {
// printf("%02X", *(output + i));
// }
// printf("\n");
// des((uint8_t *)&output,(uint8_t *)KEY,1,(uint8_t *)output2);
// for (i = 0; i < sizeof(output2); i++)
// {
// printf("%02x", *(output2 + i));
// }
// printf("\n");
DES3((char *)&input, sizeof(input), (char *)KEY, 0, (char *)output);
printf("des3 encry output :\r\n");
for (i = 0; i < sizeof(output); i++)
{
printf("%02X", *(output + i));
}
printf("\n");
DES3((char *)&output, 16, (char *)KEY, 1, (char *)output2);
printf("des3 decrypt output :\r\n");
for (i = 0; i < sizeof(output2); i++)
{
printf("%02x", *(output2 + i));
}
printf("\n");
}
void Test_Des_A(void)
{
unsigned char key[8] = { 0xB4, 0x31, 0x5B, 0x86, 0x9D, 0x7D, 0xFA, 0xA2 };
unsigned char data[8] = { 0x1F,0xAD ,0x61 ,0xA5 ,0xF7 ,0x19 ,0x77 ,0x14 };
unsigned char EncryptData[8] = { 0 };
des((uint8_t *)&data, (uint8_t *)key, 0, (uint8_t *)EncryptData);
printf("\r\nDes:\r\n");
printBuf("key:", key, 8, 32);
printBuf("plain:", data, 8, 32);
printBuf("EncryptData:", EncryptData, 8, 32);
}
void Test_Des_B(void)
{
unsigned char key[8] = { 0x13,0x34,0x57,0x79,0x9B,0xBC,0xDF,0xF1};
unsigned char data[8] = { 0x01,0x23,0x45,0x67,0x89,0xAB,0xCD,0xEF };
unsigned char EncryptData[8] = { 0 };
des_debug((uint8_t *)&data, (uint8_t *)key, 0, (uint8_t *)EncryptData);
printf("\r\nDes:\r\n");
printBuf("key:", key, 8, 32);
printBuf("plain:", data, 8, 32);
printBuf("EncryptData:", EncryptData, 8, 32);
}
void main(void)
{
printf("Start:\r\n");
Test_Des_B();
Test_Des_A();
Test_DES3();
}
将代码用 vs2013 建立一个空的控制台程序：
运行结果如下：
Start:
Hello:
1--57,1,ef
1--49,1,cd
0--41,1,ab
0--33,1,89
1--25,1,67
1--17,1,45
0--9,1,23
0--1,1,1
0--59,3,ef
0--51,3,cd
0--43,3,ab
0--35,3,89
0--27,3,67
0--19,3,45
0--11,3,23
0--3,3,1
1--61,5,ef
1--53,5,cd
0--45,5,ab
0--37,5,89
1--29,5,67
1--21,5,45
0--13,5,23
0--5,5,1
1--63,7,ef
1--55,7,cd
1--47,7,ab
1--39,7,89
1--31,7,67
1--23,7,45
1--15,7,23
1--7,7,1
1--56,0,ef
1--48,0,cd
1--40,0,ab
1--32,0,89
0--24,0,67
0--16,0,45
0--8,0,23
0--0,0,1
1--58,2,ef
0--50,2,cd
1--42,2,ab
0--34,2,89
1--26,2,67
0--18,2,45
1--10,2,23
0--2,2,1
1--60,4,ef
1--52,4,cd
1--44,4,ab
1--36,4,89
0--28,4,67
0--20,4,45
0--12,4,23
0--4,4,1
1--62,6,ef
0--54,6,cd
1--46,6,ab
0--38,6,89
1--30,6,67
0--22,6,45
1--14,6,23
0--6,6,1
a_str: cc 00 cc ff f0 aa f0 aa
Des:
key: 13 34 57 79 9b bc df f1
plain: 01 23 45 67 89 ab cd ef
EncryptData: 85 e8 13 54 0f 0a b4 05
Des:
key: b4 31 5b 86 9d 7d fa a2
plain: 1f ad 61 a5 f7 19 77 14
EncryptData: 4c 78 e9 1a f2 da 9c d3
input:
11090609243500017071901499000000
des3 encry output :
4C6EA249A24860D5BC9341022F429BD1
des3 decrypt output :
11090609243500017071901499000000
请按任意键继续. . .
解析：
1--48,0,b3
0--49,1,b3
1--50,2,b3
1--51,3,b3
0--52,4,b3
0--53,5,b3
1--54,6,b3
1--55,7,b3从上面可以看出，
这个算法，在对输入的字节进行解析的时候，
0xb3 ： bit0—-bit7 ：10110011
这个直接就是按照，b3 的字面意思解析的，
不是按照一个字节在内存中的实际存储形式，
比如小端模式，低字节在前，低比特位在前的模式解析的。
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