这次我分享的是MD5加密算法。其实MD5这个大名在还没上密码学课之前我就听说过了，那时我才刚学PHP，视频里面的讲师说像密码这种重要的信息要用md5（）函数处理下再存数据库，这么一说起来其实MD5算是我接触的第一个现代密码呢
考虑到可能有些人是为了科普一下才点进来看的，我还是结合自身经验和课本知识把MD5加密原理讲一下把，MD5算法的具体过程有以下4步：
（1）附加填充位
课本原话：填充一个‘1’和若干个‘0’使其长度模512与448同余，然后再将消息的真实长度以64bit表示附加在填充结果后面，从而使得消息长度恰好为512bit的整数倍。（不知道这段话你们看懂没有，方正我看了很久才看懂的，大概以前语文真的是体育老师教的
）
举例说明吧：
如明文为iscbupt
其16ascII码是105，115，99，98，117，112，116，转换成二进制便是01101001 01110011 01100011 01100010 01110101 01110000 01110100，这是长度为56，要使其长度模512与448同余，则需补充一个‘1’和391个‘0’。因为消息长度为56，所以用64位二进制表示为00110000 00~00（56个‘0’）。到目前为止512位全部填充完整了~
（2)初始化链接变量
课本原话：MD5中有A、B、C、D 4个32为寄存器，最开始存放4个固定的32位的整数参数，即初始链接变量，这些参数用于第1轮运算。
A=0x12345678，B=0x89ABCDEF，C=0xFEDCBA98，D=0x76543210
（3）分组处理（迭代压缩）
课本原话：MD5算法的分组处理（压缩函数）与分组密码的分组处理相似。它由4轮组成，512bit的消息分组Mi被分成16个子分组（每个子分组为32bit）参与每轮16步函数运算，即每轮包括16个步骤。每步的输入是4个32bit的链接变量（插句话~也就是A、B、C、D）和一个32bit的消息分组（是Mi哦~~），输出为32位值。经过4轮共64步后，得到的4个寄存器值分别与输入链接变量（也就是初始的A、B、C、D）进行模加，即是当前消息的中间散列值。
明文是iscbupt的Mi如下：
M0:01101001 01110011 01100011 01100010
M1:01110101 01110000 01110100 10000000
M2:00000000 00000000 00000000 00000000
................
M14:00111000 00000000 00000000 00000000
M15:00000000 00000000 00000000 00000000
（4）步函数
由于课本的图无法上传，那这里就由我来说下啦~~
所有大轮（上文所说的4轮）里的所有小轮（16轮）都是同一个步函数A=B+((A+f(B,C,D)+M[j]+T[i])<<<s)) 即B、C、D进入f函数（这里的f函数就是课本里的非线性函数，包含F、G、H、I这四种函数），得到的结果与A模加，与M[j]模加（这里的j与第几大轮第几小轮有关），与T[i]模加（这里的i从1取到64），然后进行循环左移（左移的2位数也与第几大轮第几小轮有关），再与B模加，最后得到的结果赋值给A。
一小轮结束后将A赋值给B，B赋值给C，C赋值给D，原本的D赋值给A，赋值完的A、B、C、D便可以进入下一轮。
下面来说下上文j、左移步数step、T[i]的取值情况：
第一大轮：
j在这大轮是按顺序从0取到15
第1、5、9、13小轮step=7；第2、6、10、14小轮step=12；第3、7、11、15小轮step=17；第4、8、12、16小轮step=22
第二大轮：
j的取值顺序为-----1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12
第1、5、9、13小轮step=5；第2、6、10、14小轮step=9；第3、7、11、15小轮step=14；第4、8、12、16小轮step=20
第三大轮：
j的取值顺序为----- 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2
第1、5、9、13小轮step=4；第2、6、10、14小轮step=11；第3、7、11、15小轮step=16；第4、8、12、16小轮step=23
第四大轮：
j的取值顺序为-----0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9
第1、5、9、13小轮step=6；第2、6、10、14小轮step=10；第3、7、11、15小轮step=15；第4、8、12、16小轮step=21
T[i]= 0xd76aa478,0xe8c7b756,0x242070db,0xc1bdceee,
0xf57c0faf,0x4787c62a,0xa8304613,0xfd469501,0x698098d8, 0x8b44f7af,0xffff5bb1,0x895cd7be,0x6b901122,0xfd987193, 0xa679438e,0x49b40821,0xf61e2562,0xc040b340,0x265e5a51, 0xe9b6c7aa,0xd62f105d,0x02441453,0xd8a1e681,0xe7d3fbc8, 0x21e1cde6,0xc33707d6,0xf4d50d87,0x455a14ed,0xa9e3e905, 0xfcefa3f8,0x676f02d9,0x8d2a4c8a,0xfffa3942,0x8771f681, 0x6d9d6122,0xfde5380c,0xa4beea44,0x4bdecfa9,0xf6bb4b60, 0xbebfbc70,0x289b7ec6,0xeaa127fa,0xd4ef3085,0x04881d05, 0xd9d4d039,0xe6db99e5,0x1fa27cf8,0xc4ac5665,0xf4292244, 0x432aff97,0xab9423a7,0xfc93a039,0x655b59c3,0x8f0ccc92, 0xffeff47d,0x85845dd1,0x6fa87e4f,0xfe2ce6e0,0xa3014314, 0x4e0811a1,0xf7537e82,0xbd3af235,0x2ad7d2bb,0xeb86d391
MD5的加密原理到这里就讲完了，下面来说下注意事项，也是我这次编程发现的一些理解的误区(这些结论是在明文长度不大于448的情况下成了，大于448是否成立我并没有验证过..）：
1.MD5加密算法里面的所有模加都是模2的32次加，而不是模2加。举例说明下模2的32次加：如11101000......(省略了24个‘0’)+01110000.........(省略了24个‘0’)=101011000.......(省略了24个‘0’)，共33位，取后32位最终得到01011000........(省略了24个‘0’)。
2.初始的A、B、C、D 4个链接变量与M[j]在进入步函数前要先经过大小端处理，T[i]不需要。
3.位数填充时（64bit），若长度的二进制位数不足，需要在二进制前补齐至8的整数倍而不是4的整数倍。如400=110010000
补齐后是00000001 10010000而不是00011001 00000000
4.大小端处理不是单纯指12345678->78563412，之所以有前面这种变换，是因为12、34、56、78分别表示4个十进制数，也就是说表示第1个十进制数的十六进制数经过转换放在最后，第2个放在第1个前。。当1234表示第1个十进制数、5678表示第2个十进制数时，12345678->56781234而不是78563412。如：明文长度为400，M[14]为0x01900000，转换后为0x00000190而不是0x00009001
下面附上代码（输入的明文字符个数不大于64）
- #include<stdio.h>
-
-
- void shizhuaner(int in, int n, int *md5);
- void shizhuaner_weishu(int in, int *md5);
- void shiliuzhuaner(char *t, int *temp);
- void c_out(int *a);
- void abcd_out(int *a);
- void F(int *b, int *c, int *d, int *temp1, int *temp2);
- void G(int *b, int *c, int *d, int *temp1, int *temp2);
- void H(int *b, int *c, int *d, int *temp);
- void I(int *b, int *c, int *d, int *temp);
- void yu(int *a, int *b, int *temp);
- void huo(int *a, int *b, int *temp);
- void fei(int *a, int *temp);
- void yihuo(int *a, int *b, int *temp);
- void jia(int *a, int *b, int *temp);
-
-
- void shizhuaner(int in, int n, int *md5)
- {
- int j, s, w;
- s = n / 4 + 1;
- w = n % 4;
- j = 1;
- do
- {
- md5[32 * s - 8 * w - j] = in % 2;
- in = in / 2;
- j++;
- } while (in != 0);
- while (j <=8)
- {
- md5[32 * s - 8 * w - j] = 0;
- j++;
- }
- }
-
-
- void shizhuaner_weishu(int in, int *md5)
- {
- int i,j,temp, a[64];
- for (i = 0; in!= 0; i++)
- {
- a[i] = in % 2;
- in = in / 2;
- }
- while (i % 8 != 0)
- {
- a[i] = 0;
- i++;
- }
- for (j = 0; j <i/2; j++)
- {
- temp = a[i - j - 1];
- a[i - j-1] = a[j];
- a[j] = temp;
-
- }
- temp = i/8;
- for (i=i-1; i < 64; i++)
- a[i] = 0;
- for (i = 0; i < 4; i++)
- {
- for (j = 0; j < 8; j++)
- md5[512 - temp * 8 + j - 32] = a[i * 8 + j];
- temp = temp - 1;
- }
- for (i = 0; i < 4; i++)
- {
- for (j = 0; j < 8; j++)
- md5[512 - (i + 1) * 8 + j ] = a[i * 8 + j+32];
- }
- }
-
-
- void shiliuzhuaner(char *t, int *temp)
- {
- int i;
- for (i = 0; i < 8; i++)
- {
- switch (t[i])
- {
- case '0':{temp[4 * i] = 0; temp[4 * i + 1] = 0; temp[4 * i + 2] = 0; temp[4 * i + 3] = 0; }break;
- case '1':{temp[4 * i] = 0; temp[4 * i + 1] = 0; temp[4 * i + 2] = 0; temp[4 * i + 3] = 1; }break;
- case '2':{temp[4 * i] = 0; temp[4 * i + 1] = 0; temp[4 * i + 2] = 1; temp[4 * i + 3] = 0; }break;
- case '3':{temp[4 * i] = 0; temp[4 * i + 1] = 0; temp[4 * i + 2] = 1; temp[4 * i + 3] = 1; }break;
- case '4':{temp[4 * i] = 0; temp[4 * i + 1] = 1; temp[4 * i + 2] = 0; temp[4 * i + 3] = 0; }break;
- case '5':{temp[4 * i] = 0; temp[4 * i + 1] = 1; temp[4 * i + 2] = 0; temp[4 * i + 3] = 1; }break;
- case '6':{temp[4 * i] = 0; temp[4 * i + 1] = 1; temp[4 * i + 2] = 1; temp[4 * i + 3] = 0; }break;
- case '7':{temp[4 * i] = 0; temp[4 * i + 1] = 1; temp[4 * i + 2] = 1; temp[4 * i + 3] = 1; }break;
- case '8':{temp[4 * i] = 1; temp[4 * i + 1] = 0; temp[4 * i + 2] = 0; temp[4 * i + 3] = 0; }break;
- case '9':{temp[4 * i] = 1; temp[4 * i + 1] = 0; temp[4 * i + 2] = 0; temp[4 * i + 3] = 1; }break;
- case 'a':{temp[4 * i] = 1; temp[4 * i + 1] = 0; temp[4 * i + 2] = 1; temp[4 * i + 3] = 0; }break;
- case 'b':{temp[4 * i] = 1; temp[4 * i + 1] = 0; temp[4 * i + 2] = 1; temp[4 * i + 3] = 1; }break;
- case 'c':{temp[4 * i] = 1; temp[4 * i + 1] = 1; temp[4 * i + 2] = 0; temp[4 * i + 3] = 0; }break;
- case 'd':{temp[4 * i] = 1; temp[4 * i + 1] = 1; temp[4 * i + 2] = 0; temp[4 * i + 3] = 1; }break;
- case 'e':{temp[4 * i] = 1; temp[4 * i + 1] = 1; temp[4 * i + 2] = 1; temp[4 * i + 3] = 0; }break;
- case 'f':{temp[4 * i] = 1; temp[4 * i + 1] = 1; temp[4 * i + 2] = 1; temp[4 * i + 3] = 1; }break;
- }
- }
- }
-
-
- void c_out(int *a)
- {
- int i,add;
- for (i = 1; i <= 4; i++)
- {
- add = a[32 - i * 8] * 8 + a[32 - i * 8 + 1] * 4 + a[32 - i * 8 + 2] * 2 + a[32 - i * 8 + 3];
- if (add >= 10)
- {
- switch (add)
- {
- case 10:printf("a"); break;
- case 11:printf("b"); break;
- case 12:printf("c"); break;
- case 13:printf("d"); break;
- case 14:printf("e"); break;
- case 15:printf("f"); break;
- }
- }
- else
- printf("%d", add);
- add = a[32 - i * 8+4] * 8 + a[32 - i * 8 + 5] * 4 + a[32 - i * 8 + 6] * 2 + a[32 - i * 8 + 7];
- if (add >= 10)
- {
- switch (add)
- {
- case 10:printf("a"); break;
- case 11:printf("b"); break;
- case 12:printf("c"); break;
- case 13:printf("d"); break;
- case 14:printf("e"); break;
- case 15:printf("f"); break;
- }
- }
- else
- printf("%d", add);
- }
- }
-
-
- void abcd_out(int *a)
- {
- int i, add;
- for (i = 0; i < 4; i++)
- {
- add = a[i * 8] * 8 + a[i * 8 + 1] * 4 + a[i * 8 + 2] * 2 + a[i * 8 + 3];
- if (add >= 10)
- {
- switch (add)
- {
- case 10:printf("a"); break;
- case 11:printf("b"); break;
- case 12:printf("c"); break;
- case 13:printf("d"); break;
- case 14:printf("e"); break;
- case 15:printf("f"); break;
- }
- }
- else
- printf("%d", add);
- add = a[i * 8 + 4] * 8 + a[i * 8 + 5] * 4 + a[i * 8 + 6] * 2 + a[i * 8 + 7];
- if (add >= 10)
- {
- switch (add)
- {
- case 10:printf("a"); break;
- case 11:printf("b"); break;
- case 12:printf("c"); break;
- case 13:printf("d"); break;
- case 14:printf("e"); break;
- case 15:printf("f"); break;
- }
- }
- else
- printf("%d", add);
- }
- }
-
-
- void yu(int *a, int *b,int *temp)
- {
- int i;
- for (i = 0; i < 32; i++)
- {
- if (a[i] == 1 && b[i] == 1)
- temp[i] = 1;
- else
- temp[i] = 0;
- }
- }
-
-
- void huo(int *a, int *b, int *temp)
- {
- int i;
- for (i = 0; i < 32; i++)
- {
- if (a[i] == 0 && b[i] == 0)
- temp[i] = 0;
- else
- temp[i] = 1;
- }
- }
-
-
- void fei(int *a, int *temp)
- {
- int i;
- for (i = 0; i < 32; i++)
- {
- if (a[i] == 0)
- temp[i] = 1;
- else
- temp[i] = 0;
- }
- }
-
-
- void yihuo(int *a, int *b, int *temp)
- {
- int i;
- for (i = 0; i < 32; i++)
- {
- if (a[i] != b[i])
- temp[i] = 1;
- else
- temp[i] = 0;
- }
- }
-
-
- void jia(int *a, int *b, int *temp)
- {
- int i,jin;
- jin = 0;
- for (i = 0; i < 32; i++)
- {
- if (a[31 - i] + b[31 - i] + jin>1)
- {
- temp[31 - i] = a[31 - i] + b[31 - i] + jin - 2;
- jin = 1;
- }
- else
- {
- temp[31 - i] = a[31 - i] + b[31 - i]+jin;
- jin = 0;
- }
- }
- }
-
-
- void F(int *b, int *c, int *d,int *temp1,int *temp2)
- {
-
- yu(b, c, temp1);
- fei(b, temp2);
- yu(temp2, d, temp2);
- huo(temp1, temp2, temp2);
- }
-
-
- void G(int *b, int *c, int *d, int *temp1, int *temp2)
- {
-
- yu(b, d, temp1);
- fei(d, temp2);
- yu(temp2, c, temp2);
- huo(temp1, temp2, temp2);
- }
-
-
- void H(int *b, int *c, int *d, int *temp)
- {
-
- yihuo(b, c, temp);
- yihuo(temp, d, temp);
- }
-
-
- void I(int *b, int *c, int *d, int *temp)
- {
-
- fei(d, temp);
- huo(b, temp, temp);
- yihuo(c, temp, temp);
- }
-
-
- void move(int step, int *temp1, int *temp2)
- {
- int i;
- for (i = 0; i < 32 - step; i++)
- temp2[i] = temp1[i + step];
- for (i = 0; i < step; i++)
- temp2[32 - step + i] = temp1[i];
- }
-
-
- void round(int *a, int *b, int *c, int *d, int *m, int *md5, int r, char *t1,
- char *t2, char *t3, char *t4, char *t5, char *t6, char *t7, char *t8, char *t9,
- char *t10, char *t11, char *t12, char *t13, char *t14, char *t15, char *t16 )
- {
- int i, j, in, step , temp1[32], temp2[32];
- for (i = 0; i < 16; i++)
- {
- switch (r)
- {
- case 1:F(b, c, d, temp1, temp2); break;
- case 2:G(b, c, d, temp1, temp2); break;
- case 3:H(b, c, d, temp2); break;
- case 4:I(b, c, d, temp2); break;
- }
- in = m[i];
- for (j = 0; j < 32; j++)
- temp1[j] = md5[in * 32 + j];
- jia(temp2, temp1, temp2);
- switch (i + 1)
- {
- case 1:shiliuzhuaner(t1, temp1); break;
- case 2:shiliuzhuaner(t2, temp1); break;
- case 3:shiliuzhuaner(t3, temp1); break;
- case 4:shiliuzhuaner(t4, temp1); break;
- case 5:shiliuzhuaner(t5, temp1); break;
- case 6:shiliuzhuaner(t6, temp1); break;
- case 7:shiliuzhuaner(t7, temp1); break;
- case 8:shiliuzhuaner(t8, temp1); break;
- case 9:shiliuzhuaner(t9, temp1); break;
- case 10:shiliuzhuaner(t10, temp1); break;
- case 11:shiliuzhuaner(t11, temp1); break;
- case 12:shiliuzhuaner(t12, temp1); break;
- case 13:shiliuzhuaner(t13, temp1); break;
- case 14:shiliuzhuaner(t14, temp1); break;
- case 15:shiliuzhuaner(t15, temp1); break;
- case 16:shiliuzhuaner(t16, temp1); break;
- }
- jia(temp2, temp1, temp2);
- jia(temp2, a, temp2);
- switch(r)
- {
- case 1:switch (i % 4 + 1){ case 1:step = 7; break; case 2:step = 12; break; case 3:step = 17; break; case 4:step = 22; break; }break;
- case 2:switch (i % 4 + 1){ case 1:step = 5; break; case 2:step = 9; break; case 3:step = 14; break; case 4:step = 20; break; }break;
- case 3:switch (i % 4 + 1){ case 1:step = 4; break; case 2:step = 11; break; case 3:step = 16; break; case 4:step = 23; break; }break;
- case 4:switch (i % 4 + 1){ case 1:step = 6; break; case 2:step = 10; break; case 3:step = 15; break; case 4:step = 21; break; }break;
- }
- move(step, temp2, temp1);
- jia(temp1, b, temp2);
- for (j = 0; j < 32; j++)
- {
- a[j] = d[j];
- d[j] = c[j];
- c[j] = b[j];
- b[j] = temp2[j];
- }
-
-
-
-
-
-
-
-
-
-
-
-
- }
- }
-
-
- int main()
- {
- char ch,
-
- t1[8] = { 'd', '7', '6', 'a', 'a', '4', '7', '8' },
- t2[8] = { 'e', '8', 'c', '7', 'b', '7', '5', '6' },
- t3[8] = { '2', '4', '2', '0', '7', '0', 'd', 'b' },
- t4[8] = { 'c', '1', 'b', 'd', 'c', 'e', 'e', 'e' },
- t5[8] = { 'f', '5', '7', 'c', '0', 'f', 'a', 'f' },
- t6[8] = { '4', '7', '8', '7', 'c', '6', '2', 'a' },
- t7[8] = { 'a', '8', '3', '0', '4', '6', '1', '3' },
- t8[8] = { 'f', 'd', '4', '6', '9', '5', '0', '1' },
- t9[8] = { '6', '9', '8', '0', '9', '8', 'd', '8' },
- t10[8] = { '8', 'b', '4', '4', 'f', '7', 'a', 'f' },
- t11[8] = { 'f', 'f', 'f', 'f', '5', 'b', 'b', '1' },
- t12[8] = { '8', '9', '5', 'c', 'd', '7', 'b', 'e' },
- t13[8] = { '6', 'b', '9', '0', '1', '1', '2', '2' },
- t14[8] = { 'f', 'd', '9', '8', '7', '1', '9', '3' },
- t15[8] = { 'a', '6', '7', '9', '4', '3', '8', 'e' },
- t16[8] = { '4', '9', 'b', '4', '0', '8', '2', '1' },
- t17[8] = { 'f', '6', '1', 'e', '2', '5', '6', '2' },
- t18[8] = { 'c', '0', '4', '0', 'b', '3', '4', '0' },
- t19[8] = { '2', '6', '5', 'e', '5', 'a', '5', '1' },
- t20[8] = { 'e', '9', 'b', '6', 'c', '7', 'a', 'a' },
- t21[8] = { 'd', '6', '2', 'f', '1', '0', '5', 'd' },
- t22[8] = { '0', '2', '4', '4', '1', '4', '5', '3' },
- t23[8] = { 'd', '8', 'a', '1', 'e', '6', '8', '1' },
- t24[8] = { 'e', '7', 'd', '3', 'f', 'b', 'c', '8' },
- t25[8] = { '2', '1', 'e', '1', 'c', 'd', 'e', '6' },
- t26[8] = { 'c', '3', '3', '7', '0', '7', 'd', '6' },
- t27[8] = { 'f', '4', 'd', '5', '0', 'd', '8', '7' },
- t28[8] = { '4', '5', '5', 'a', '1', '4', 'e', 'd' },
- t29[8] = { 'a', '9', 'e', '3', 'e', '9', '0', '5' },
- t30[8] = { 'f', 'c', 'e', 'f', 'a', '3', 'f', '8' },
- t31[8] = { '6', '7', '6', 'f', '0', '2', 'd', '9' },
- t32[8] = { '8', 'd', '2', 'a', '4', 'c', '8', 'a' },
- t33[8] = { 'f', 'f', 'f', 'a', '3', '9', '4', '2' },
- t34[8] = { '8', '7', '7', '1', 'f', '6', '8', '1' },
- t35[8] = { '6', 'd', '9', 'd', '6', '1', '2', '2' },
- t36[8] = { 'f', 'd', 'e', '5', '3', '8', '0', 'c' },
- t37[8] = { 'a', '4', 'b', 'e', 'e', 'a', '4', '4' },
- t38[8] = { '4', 'b', 'd', 'e', 'c', 'f', 'a', '9' },
- t39[8] = { 'f', '6', 'b', 'b', '4', 'b', '6', '0' },
- t40[8] = { 'b', 'e', 'b', 'f', 'b', 'c', '7', '0' },
- t41[8] = { '2', '8', '9', 'b', '7', 'e', 'c', '6' },
- t42[8] = { 'e', 'a', 'a', '1', '2', '7', 'f', 'a' },
- t43[8] = { 'd', '4', 'e', 'f', '3', '0', '8', '5' },
- t44[8] = { '0', '4', '8', '8', '1', 'd', '0', '5' },
- t45[8] = { 'd', '9', 'd', '4', 'd', '0', '3', '9' },
- t46[8] = { 'e', '6', 'd', 'b', '9', '9', 'e', '5' },
- t47[8] = { '1', 'f', 'a', '2', '7', 'c', 'f', '8' },
- t48[8] = { 'c', '4', 'a', 'c', '5', '6', '6', '5' },
- t49[8] = { 'f', '4', '2', '9', '2', '2', '4', '4' },
- t50[8] = { '4', '3', '2', 'a', 'f', 'f', '9', '7' },
- t51[8] = { 'a', 'b', '9', '4', '2', '3', 'a', '7' },
- t52[8] = { 'f', 'c', '9', '3', 'a', '0', '3', '9' },
- t53[8] = { '6', '5', '5', 'b', '5', '9', 'c', '3' },
- t54[8] = { '8', 'f', '0', 'c', 'c', 'c', '9', '2' },
- t55[8] = { 'f', 'f', 'e', 'f', 'f', '4', '7', 'd' },
- t56[8] = { '8', '5', '8', '4', '5', 'd', 'd', '1' },
- t57[8] = { '6', 'f', 'a', '8', '7', 'e', '4', 'f' },
- t58[8] = { 'f', 'e', '2', 'c', 'e', '6', 'e', '0' },
- t59[8] = { 'a', '3', '0', '1', '4', '3', '1', '4' },
- t60[8] = { '4', 'e', '0', '8', '1', '1', 'a', '1' },
- t61[8] = { 'f', '7', '5', '3', '7', 'e', '8', '2' },
- t62[8] = { 'b', 'd', '3', 'a', 'f', '2', '3', '5' },
- t63[8] = { '2', 'a', 'd', '7', 'd', '2', 'b', 'b' },
- t64[8] = { 'e', 'b', '8', '6', 'd', '3', '9', '1' };
- int in, n = 0, i,j,addup;
- int md5[512],
-
- m1[16] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
- m2[16] = { 1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12 },
- m3[16] = { 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2 },
- m4[16] = { 0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9 },
-
-
- a[32] = { 0, 1, 1, 0, 0, 1, 1, 1,
- 0, 1, 0, 0, 0, 1, 0, 1,
- 0, 0, 1, 0, 0, 0, 1, 1,
- 0, 0, 0, 0, 0, 0, 0, 1 },
- a1[32] = { 0, 1, 1, 0, 0, 1, 1, 1,
- 0, 1, 0, 0, 0, 1, 0, 1,
- 0, 0, 1, 0, 0, 0, 1, 1,
- 0, 0, 0, 0, 0, 0, 0, 1 },
- b[32] = { 1, 1, 1, 0, 1, 1, 1, 1,
- 1, 1, 0, 0, 1, 1, 0, 1,
- 1, 0, 1, 0, 1, 0, 1, 1,
- 1, 0, 0, 0, 1, 0, 0, 1 },
- b1[32] = { 1, 1, 1, 0, 1, 1, 1, 1,
- 1, 1, 0, 0, 1, 1, 0, 1,
- 1, 0, 1, 0, 1, 0, 1, 1,
- 1, 0, 0, 0, 1, 0, 0, 1 },
- c[32] = { 1, 0, 0, 1, 1, 0, 0, 0,
- 1, 0, 1, 1, 1, 0, 1, 0,
- 1, 1, 0, 1, 1, 1, 0, 0,
- 1, 1, 1, 1, 1, 1, 1, 0 },
- c1[32] = { 1, 0, 0, 1, 1, 0, 0, 0,
- 1, 0, 1, 1, 1, 0, 1, 0,
- 1, 1, 0, 1, 1, 1, 0, 0,
- 1, 1, 1, 1, 1, 1, 1, 0 },
- d[32] = { 0, 0, 0, 1, 0, 0, 0, 0,
- 0, 0, 1, 1, 0, 0, 1, 0,
- 0, 1, 0, 1, 0, 1, 0, 0,
- 0, 1, 1, 1, 0, 1, 1, 0 },
- d1[32] = { 0, 0, 0, 1, 0, 0, 0, 0,
- 0, 0, 1, 1, 0, 0, 1, 0,
- 0, 1, 0, 1, 0, 1, 0, 0,
- 0, 1, 1, 1, 0, 1, 1, 0 };
- printf("请输入需加密的明文（长度不大于56)\n");
- ch = getchar();
- while (ch!='\n'&&n<57)
- {
- in = (int)ch;
- shizhuaner(in, n, md5);
- n++;
- ch = getchar();
- }
- i = 0;
- addup = n;
- while (n% 4 != 0 && n<56)
- {
- int s, w, j;
- s = n / 4 + 1;
- w = n % 4;
- j = 1;
- do
- {
- md5[32 * s - 8 * w - j] = 0;
- j++;
- } while (j<=7);
- if (i == 0)
- {
- md5[32 * s - 8 * w - j] = 1;
- i = 1;
- }
- n++;
- }
- if (i == 0)
- {
- for (j = 0; j < 32; j++)
- md5[n * 8 + j] = 0;
- md5[8 * n + 24] = 1;
- }
- for (i = 0; i < 512; i++)
- {
- if (md5[i] == 1)
- md5[i] = 1;
- else
- md5[i] = 0;
- }
- printf("\n");
- shizhuaner_weishu(addup * 8, md5);
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- round(a, b, c, d, m1, md5, 1, t1, t2, t3, t4, t5, t6, t7, t8, t9, t10, t11, t12, t13, t14, t15, t16);
- round(a, b, c, d, m2, md5, 2, t17, t18, t19, t20, t21, t22, t23, t24, t25, t26, t27, t28, t29, t30, t31, t32);
- round(a, b, c, d, m3, md5, 3, t33, t34, t35, t36, t37, t38, t39, t40, t41, t42, t43, t44, t45, t46, t47, t48);
- round(a, b, c, d, m4, md5, 4, t49, t50, t51, t52, t53, t54, t55, t56, t57, t58, t59, t60, t61, t62, t63, t64);
- printf("\n");
-
- jia(a, a1, a);
- jia(b, b1, b);
- jia(c, c1, c);
- jia(d, d1, d);
-
- printf("密文:\n");
- c_out(a);
- c_out(b);
- c_out(c);
- c_out(d);
- printf("\n");
- return 0;
- }
运行结果：
示例1
示例2
示例3
使用说明：
1.因为我对位运算不是很了解，所以这份代码是没有使用位运算的。如果看时觉得混乱可以发邮件给我
2.默认情况下这份代码是不输出M[0]~M[15]和4大轮16小轮中A、B、C、D的变化情况的，如果想输出以上内容的话，在适当的位置取消注释便可（代码中有注释说明位置）
