md5加密算法c语言版

from: http://blog.sina.com.cn/s/blog_693de6100101kcu6.html

注：以下是md5加密算法c语言版(16/32位)

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网上找到的md5函数的实现，包括三个文件，依次如下：

头文件 TL_MD5.h

 [cpp]
 #ifndef MD5_H
 #define MD5_H  

 typedef struct
 {
     unsigned int count[];
     unsigned int state[];
     unsigned char buffer[];
 }MD5_CTX;  

 #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)))
 #define FF(a,b,c,d,x,s,ac) \
 { \
     a += F(b,c,d) + x + ac; \
     a = ROTATE_LEFT(a,s); \
     a += b; \
 }
 #define GG(a,b,c,d,x,s,ac) \
 { \
     a += G(b,c,d) + x + ac; \
     a = ROTATE_LEFT(a,s); \
     a += b; \
 }
 #define HH(a,b,c,d,x,s,ac) \
 { \
     a += H(b,c,d) + x + ac; \
     a = ROTATE_LEFT(a,s); \
     a += b; \
 }
 #define II(a,b,c,d,x,s,ac) \
 { \
     a += I(b,c,d) + x + ac; \
     a = ROTATE_LEFT(a,s); \
     a += b; \
 }
 void MD5Init(MD5_CTX *context);
 void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen);
 void MD5Final(MD5_CTX *context,unsigned char digest[]);
 void MD5Transform(unsigned int state[],unsigned char block[]);
 void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len);
 void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len);  

 #endif  

C/C++语言实现文件 TL_MD5.c 或者 TL_MD5.cpp

 [cpp]
 #include <string.h>
 #include "md5.h"  

 unsigned char PADDING[]={0x80,,,,,,,,,,,,,,,,
 ,,,,,,,,,,,,,,,,
 ,,,,,,,,,,,,,,,,
 ,,,,,,,,,,,,,,,};  

 void MD5Init(MD5_CTX *context)
 {
     context->count[] = ;
     context->count[] = ;
     context->state[] = 0x67452301;
     context->state[] = 0xEFCDAB89;
     context->state[] = 0x98BADCFE;
     context->state[] = 0x10325476;
 }
 void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen)
 {
     unsigned int i = ,index = ,partlen = ;
     index = (context->count[] >> ) & 0x3F;
     partlen =  - index;
     context->count[] += inputlen << ;
     if(context->count[] < (inputlen << ))
         context->count[]++;
     context->count[] += inputlen >> ;  

     if(inputlen >= partlen)
     {
         memcpy(&context->buffer[index],input,partlen);
         MD5Transform(context->state,context->buffer);
         for(i = partlen;i+ <= inputlen;i+=)
             MD5Transform(context->state,&input[i]);
         index = ;
     }
     else
     {
         i = ;
     }
     memcpy(&context->buffer[index],&input[i],inputlen-i);
 }
 void MD5Final(MD5_CTX *context,unsigned char digest[])
 {
     unsigned int index = ,padlen = ;
     unsigned char bits[];
     index = (context->count[] >> ) & 0x3F;
     padlen = (index < )?(-index):(-index);
     MD5Encode(bits,context->count,);
     MD5Update(context,PADDING,padlen);
     MD5Update(context,bits,);
     MD5Encode(digest,context->state,);
 }
 void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len)
 {
     unsigned int i = ,j = ;
     while(j < len)
     {
         output[j] = input[i] & 0xFF;
         output[j+] = (input[i] >> ) & 0xFF;
         output[j+] = (input[i] >> ) & 0xFF;
         output[j+] = (input[i] >> ) & 0xFF;
         i++;
         j+=;
     }
 }
 void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len)
 {
     unsigned int i = ,j = ;
     while(j < len)
     {
         output[i] = (input[j]) |
             (input[j+] << ) |
             (input[j+] << ) |
             (input[j+] << );
         i++;
         j+=;
     }
 }
 void MD5Transform(unsigned int state[],unsigned char block[])
 {
     unsigned int a = state[];
     unsigned int b = state[];
     unsigned int c = state[];
     unsigned int d = state[];
     unsigned int x[];
     MD5Decode(x,block,);
     FF(a, b, c, d, x[ ], , 0xd76aa478);
     FF(d, a, b, c, x[ ], , 0xe8c7b756);
     FF(c, d, a, b, x[ ], , 0x242070db);
     FF(b, c, d, a, x[ ], , 0xc1bdceee);
     FF(a, b, c, d, x[ ], , 0xf57c0faf);
     FF(d, a, b, c, x[ ], , 0x4787c62a);
     FF(c, d, a, b, x[ ], , 0xa8304613);
     FF(b, c, d, a, x[ ], , 0xfd469501);
     FF(a, b, c, d, x[ ], , 0x698098d8);
     FF(d, a, b, c, x[ ], , 0x8b44f7af);
     FF(c, d, a, b, x[], , 0xffff5bb1);
     FF(b, c, d, a, x[], , 0x895cd7be);
     FF(a, b, c, d, x[], , 0x6b901122);
     FF(d, a, b, c, x[], , 0xfd987193);
     FF(c, d, a, b, x[], , 0xa679438e);
     FF(b, c, d, a, x[], , 0x49b40821);   

     GG(a, b, c, d, x[ ], , 0xf61e2562);
     GG(d, a, b, c, x[ ], , 0xc040b340);
     GG(c, d, a, b, x[], , 0x265e5a51);
     GG(b, c, d, a, x[ ], , 0xe9b6c7aa);
     GG(a, b, c, d, x[ ], , 0xd62f105d);
     GG(d, a, b, c, x[], ,  0x2441453);
     GG(c, d, a, b, x[], , 0xd8a1e681);
     GG(b, c, d, a, x[ ], , 0xe7d3fbc8);
     GG(a, b, c, d, x[ ], , 0x21e1cde6);
     GG(d, a, b, c, x[], , 0xc33707d6);
     GG(c, d, a, b, x[ ], , 0xf4d50d87);
     GG(b, c, d, a, x[ ], , 0x455a14ed);
     GG(a, b, c, d, x[], , 0xa9e3e905);
     GG(d, a, b, c, x[ ], , 0xfcefa3f8);
     GG(c, d, a, b, x[ ], , 0x676f02d9);
     GG(b, c, d, a, x[], , 0x8d2a4c8a);   

     HH(a, b, c, d, x[ ], , 0xfffa3942);
     HH(d, a, b, c, x[ ], , 0x8771f681);
     HH(c, d, a, b, x[], , 0x6d9d6122);
     HH(b, c, d, a, x[], , 0xfde5380c);
     HH(a, b, c, d, x[ ], , 0xa4beea44);
     HH(d, a, b, c, x[ ], , 0x4bdecfa9);
     HH(c, d, a, b, x[ ], , 0xf6bb4b60);
     HH(b, c, d, a, x[], , 0xbebfbc70);
     HH(a, b, c, d, x[], , 0x289b7ec6);
     HH(d, a, b, c, x[ ], , 0xeaa127fa);
     HH(c, d, a, b, x[ ], , 0xd4ef3085);
     HH(b, c, d, a, x[ ], ,  0x4881d05);
     HH(a, b, c, d, x[ ], , 0xd9d4d039);
     HH(d, a, b, c, x[], , 0xe6db99e5);
     HH(c, d, a, b, x[], , 0x1fa27cf8);
     HH(b, c, d, a, x[ ], , 0xc4ac5665);   

     II(a, b, c, d, x[ ], , 0xf4292244);
     II(d, a, b, c, x[ ], , 0x432aff97);
     II(c, d, a, b, x[], , 0xab9423a7);
     II(b, c, d, a, x[ ], , 0xfc93a039);
     II(a, b, c, d, x[], , 0x655b59c3);
     II(d, a, b, c, x[ ], , 0x8f0ccc92);
     II(c, d, a, b, x[], , 0xffeff47d);
     II(b, c, d, a, x[ ], , 0x85845dd1);
     II(a, b, c, d, x[ ], , 0x6fa87e4f);
     II(d, a, b, c, x[], , 0xfe2ce6e0);
     II(c, d, a, b, x[ ], , 0xa3014314);
     II(b, c, d, a, x[], , 0x4e0811a1);
     II(a, b, c, d, x[ ], , 0xf7537e82);
     II(d, a, b, c, x[], , 0xbd3af235);
     II(c, d, a, b, x[ ], , 0x2ad7d2bb);
     II(b, c, d, a, x[ ], , 0xeb86d391);
     state[] += a;
     state[] += b;
     state[] += c;
     state[] += d;
 }  

md5函数测试代码文件

 [cpp]
 #include
 #include
 #include
 #include "md5.h"  

 int main(int argc, char *argv[])
 {
     MD5_CTX md5;
     MD5Init(&md5);
     int i;
     unsigned char encrypt[] ="admin";//21232f297a57a5a743894a0e4a801fc3
     unsigned char decrypt[];
     MD5Update(&md5,encrypt,strlen((char *)encrypt));
     MD5Final(&md5,decrypt);
     printf("加密前:%s\n加密后16位:",encrypt);
     for(i=;i<;i++)
     {
         printf("02x",decrypt[i]);  //02x前需要加上 %
     }  

     printf("\n加密前:%s\n加密后32位:",encrypt);
     for(i=;i<;i++)
     {
         printf("02x",decrypt[i]);  //02x前需要加上 %
     }  

     getchar();  

     return ;
 }  

MD5加密常用字符

7a57a5a743894a0e admin(16位MD5小写加密)
972130B75066C825 ADMIN(16位MD5大写加密)
21232f297a57a5a743894a0e4a801fc3 admin(32位MD5小写加密)
73ACD9A5972130B75066C82595A1FAE3 ADMIN(32位MD5大写加密)
49ba59abbe56e057 123456(16位MD5小写加密)
e10adc3949ba59abbe56e057f20f883e 123456(32位MD5小写加密)
469e80d32c0559f8 admin888(16位MD5小写加密)
2299413865C28A35 ADMIN888(16位MD5大写加密)
7fef6171469e80d32c0559f88b377245 admin888(32位MD5小写加密)
A1F63A962299413865C28A3593D359B0 ADMIN888(32位MD5大写加密)

md5知识扫盲

MD5：是一个散列算法，但非加密算法（因为没有密钥）
MD5是一种单向散列函数，单向散列函数的作用是将任何长度的一段数据散列成固定长度。常用于生成消息认证码等等，可以与非对称算法一起用于数字签名。
标准见http://www.ietf.org/rfc/rfc1321.txt

在线MD5计算 http://www.cmd5.com/