MD5测试程序（C语言版本）

来源：互联网发布：魔戒知乎编辑：程序博客网时间：2024/06/05 05:36

以下代码在 gcc 和 vc6.0 下编译通过，我添加了一些注释以帮助理解。

// md5.h

#ifndef _RPCENG_MD5_H

#define _RPCENG_MD5_H

// #include <string.h>

typedef struct

{

unsigned int state[4];

unsigned int count[2];

unsigned char buffer[64];

} MD5Context;

void MD5_Init(MD5Context * context);

void MD5_Update(MD5Context * context, unsigned char * buf, unsigned int len);

void MD5_Final(MD5Context * context, unsigned char digest[16]);

#endif /* end of _RPCENG_MD5_H */

// md5.c

#include <stdio.h>

#include <string.h>

#include "md5.h"

#define S11 7

#define S12 12

#define S13 17

#define S14 22

#define S21 5

#define S22 9

#define S23 14

#define S24 20

#define S31 4

#define S32 11

#define S33 16

#define S34 23

#define S41 6

#define S42 10

#define S43 15

#define S44 21

// 明文末尾填充的数据

static unsigned char PADDING[64] =

{

0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

};

// 四个非线性函数，每轮用一个

#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))

#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))

#define H(x, y, z) ((x) ^ (y) ^ (z))

#define I(x, y, z) ((y) ^ ((x) | (~z)))

#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

// 每轮迭代中的四种操作

#define FF(a, b, c, d, x, s, ac) \

{ \

(a) += F((b), (c), (d)) + (x) + (unsigned int)(ac); \

(a) = ROTATE_LEFT((a), (s)); \

(a) += (b); \

}

#define GG(a, b, c, d, x, s, ac) \

{ \

(a) += G((b), (c), (d)) + (x) + (unsigned int)(ac); \

(a) = ROTATE_LEFT((a), (s)); \

(a) += (b); \

}

#define HH(a, b, c, d, x, s, ac) \

{ \

(a) += H((b), (c), (d)) + (x) + (unsigned int)(ac); \

(a) = ROTATE_LEFT((a), (s)); \

(a) += (b); \

}

#define II(a, b, c, d, x, s, ac) \

{ \

(a) += I((b), (c), (d)) + (x) + (unsigned int)(ac); \

(a) = ROTATE_LEFT((a), (s)); \

(a) += (b); \

}

// 将32位的unsigned int编码成8位的unsigned char

static void MD5_Encode(unsigned char * output, unsigned int * input, unsigned int len)

{

unsigned int i, j;

for (i = 0, j = 0; j < len; i++, j += 4)

{

output[j] = (unsigned char) (input[i] & 0xff);

output[j + 1] = (unsigned char) ((input[i] >> 8) & 0xff);

output[j + 2] = (unsigned char) ((input[i] >> 16) & 0xff);

output[j + 3] = (unsigned char) ((input[i] >> 24) & 0xff);

}

// 将8位的unsigned char解码成32位的unsigned int

static void MD5_Decode(unsigned int * output, unsigned char * input, unsigned int len)

{

unsigned int i, j;

for (i = 0, j = 0; j < len; i++, j += 4)

{

output[i] = ((unsigned int) input[j]) |

(((unsigned int) input[j + 1]) << 8) |

(((unsigned int) input[j + 2]) << 16) |

(((unsigned int) input[j + 3]) << 24);

}

// MD5主循环：四轮运算

// unsigned int为32位，输出128位认证码unsigned int state[4]，4个32位变量；

// unsigned char为8位，输入512位分组unsigned char block[64]，分为16个子分组。

static void MD5_Transform(unsigned int state[4], unsigned char block[64])

{

unsigned int a = state[0], b = state[1], c = state[2], d = state[3], x[16];

MD5_Decode(x, block, 64);

/* Round 1 */

FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */

FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */

FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */

FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */

FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */

FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */

FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */

FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */

FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */

FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */

FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */

FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */

FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */

FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */

FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */

FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

/* Round 2 */

GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */

GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */

GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */

GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */

GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */

GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */

GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */

GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */

GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */

GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */

GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */

GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */

GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */

GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */

GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */

GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

/* Round 3 */

HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */

HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */

HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */

HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */

HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */

HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */

HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */

HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */

HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */

HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */

HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */

HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */

HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */

HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */

HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */

HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */

/* Round 4 */

II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */

II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */

II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */

II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */

II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */

II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */

II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */

II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */

II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */

II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */

II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */

II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */

II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */

II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */

II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */

II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */

state[0] += a;

state[1] += b;

state[2] += c;

state[3] += d;

//memset((char *) x, 0, sizeof(x));

}

// MD5运算变量初始化

void MD5_Init(MD5Context * context)

{

context->count[0] = context->count[1] = 0;

// 链接变量chaining variable

context->state[0] = 0x67452301;

context->state[1] = 0xefcdab89;

context->state[2] = 0x98badcfe;

context->state[3] = 0x10325476;

}

// 认证算法运行过程

void MD5_Update(MD5Context * context, unsigned char * buf, unsigned int len)

{

unsigned int i, index, partLen;

index = (unsigned int) ((context->count[0] >> 3) & 0x3F); // 字节数组下表索引

// 明文长度（以字节为单位）计入MD5结构体count里

if ((context->count[0] += ((unsigned int) len << 3)) < ((unsigned int) len << 3))

context->count[1]++;

context->count[1] += ((unsigned int) len >> 29); // ?? 调试过程中context->count[1]一直为0

partLen = 64 - index; // 添加的数据长度离64字节（即512位分组）相差距离

if (len >= partLen) // 若添满64字节：认证

{

memcpy((char *) &context->buffer[index], (char *) buf, partLen); //将明文分组追加到MD5结构体buffer里

// 下一分组继续运行与上一分组同样的算法

MD5_Transform(context->state, context->buffer);

for (i = partLen; i + 63 < len; i += 64) // 512位分组即64字节

MD5_Transform(context->state, &buf[i]);

index = 0;

}

else // 否则，不认证，等后面继续追加数据

{

i = 0;

}

// 留下不完整分组在MD5结构体buffer里

memcpy((char *) &context->buffer[index], (char *) &buf[i], len - i);

}

// 末尾的不完整分组认证过程

void MD5_Final(MD5Context * context, unsigned char digest[16])

{

unsigned char bits[8];

unsigned int index, padLen;

MD5_Encode(bits, context->count, 8); // 明文长度编码为以字节为单位

index = (unsigned int) ((context->count[0] >> 3) & 0x3f);

padLen = (index < 56) ? (56 - index) : (120 - index);

MD5_Update(context, PADDING, padLen); // 在明文末尾填充PADDING数据

MD5_Update(context, bits, 8); // 在明文末尾填充明文长度，并认证

MD5_Encode(digest, context->state, 16); // 将认证码MAC编码成128位unsigned int型数据输出

//memset((char *) context, 0, sizeof(*context));

}

int main(){

unsigned int i,j,len;

// MD5变量结构体

MD5Context context;

unsigned char buff[16];

// 明文

char str[7][100] = // !!

{

"",

"a",

"abc",

"message digest",

"abcdefghijklmnopqrstuvwxyz",

"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",

"12345678901234567890123456789012345678901234567890123456789012345678901234567890"

};

for(i=0;i<6;i++)

{

len = strlen(str[i]);

// MD5运算变量初始化

MD5_Init(&context);

// 明文认证

MD5_Update(&context,(unsigned char *)str[i], len);

// 末尾的不完整分组认证

MD5_Final(&context,buff);

// 打印结果

printf("MD5(\"%s\") = ",str[i]);

for(j=0;j<16;j++)

{

printf("%x",(buff[j] & 0xF0)>>4);

printf("%x",buff[j] & 0x0F);

}

printf("\n *********************************************************** \n");

}

printf("Waiting... ");

getchar();

return 0;

}

运行结果如下：

MD5("") = d41d8cd98f00b204e9800998ecf8427e

***********************************************************

MD5("a") = 0cc175b9c0f1b6a831c399e269772661

***********************************************************

MD5("abc") = 900150983cd24fb0d6963f7d28e17f72

***********************************************************

MD5("message digest") = f96b697d7cb7938d525a2f31aaf161d0

***********************************************************

MD5("abcdefghijklmnopqrstuvwxyz") = c3fcd3d76192e4007dfb496cca67e13b

***********************************************************

MD5("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789") = d174ab9

8d277d9f5a5611c2c9f419d9f

***********************************************************

Waiting...

参考资料：

http://blog.csdn.net/kofsky/article/details/2128611（C版本实现）

http://my.oschina.net/u/158916/blog/29329 （C++版本的实现）

http://book.douban.com/subject/1088180/（《应用密码学》的豆瓣链接）

RFC1321 The MD5 Message-Digest Algorithm 附录A有C语言的参考实现。

附python环境下使用pycrypto库的代码：

[python] view plaincopyprint?
from Crypto.Hash import MD5  
  
strlist = ["",  
"a",  
"abc",  
"message digest",  
"abcdefghijklmnopqrstuvwxyz",  
"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789",  
"12345678901234567890123456789012345678901234567890123456789012345678901234567890"]  
  
for s in strlist:  
    m = MD5.new()  
    m.update(s)  
    print (s, m.hexdigest())  

执行结果：

('', 'd41d8cd98f00b204e9800998ecf8427e')('a', '0cc175b9c0f1b6a831c399e269772661')('abc', '900150983cd24fb0d6963f7d28e17f72')('message digest', 'f96b697d7cb7938d525a2f31aaf161d0')('abcdefghijklmnopqrstuvwxyz', 'c3fcd3d76192e4007dfb496cca67e13b')('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789', 'd174ab98d277d9f5a5611c2c9f419d9f')('12345678901234567890123456789012345678901234567890123456789012345678901234567890', '57edf4a22be3c955ac49da2e2107b67a')