MD5摘要算法实现

 1 #ifndef MD5_H
 2 #define MD5_H
 3  
 4 typedef struct
 5 {
 6     unsigned int count[2];
 7     unsigned int state[4];
 8     unsigned char buffer[64];   
 9 }MD5_CTX;
10  
11                          
12 #define F(x,y,z) ((x & y) | (~x & z))
13 #define G(x,y,z) ((x & z) | (y & ~z))
14 #define H(x,y,z) (x^y^z)
15 #define I(x,y,z) (y ^ (x | ~z))
16 #define ROTATE_LEFT(x,n) ((x << n) | (x >> (32-n)))
17 #define FF(a,b,c,d,x,s,ac) 18           { 19           a += F(b,c,d) + x + ac; 20           a = ROTATE_LEFT(a,s); 21           a += b; 22           }
23 #define GG(a,b,c,d,x,s,ac) 24           { 25           a += G(b,c,d) + x + ac; 26           a = ROTATE_LEFT(a,s); 27           a += b; 28           }
29 #define HH(a,b,c,d,x,s,ac) 30           { 31           a += H(b,c,d) + x + ac; 32           a = ROTATE_LEFT(a,s); 33           a += b; 34           }
35 #define II(a,b,c,d,x,s,ac) 36           { 37           a += I(b,c,d) + x + ac; 38           a = ROTATE_LEFT(a,s); 39           a += b; 40           }                                            
41 void MD5Init(MD5_CTX *context);
42 void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen);
43 void MD5Final(MD5_CTX *context,unsigned char digest[16]);
44 void MD5Transform(unsigned int state[4],unsigned char block[64]);
45 void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len);
46 void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len);
47  
48 #endif

  1 #include <memory.h>
  2 #include "md5.h"
  3  
  4 unsigned char PADDING[]={0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  5                          0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  6                          0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
  7                          0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
  8                          
  9 void MD5Init(MD5_CTX *context)
 10 {
 11      context->count[0] = 0;
 12      context->count[1] = 0;
 13      context->state[0] = 0x67452301;
 14      context->state[1] = 0xEFCDAB89;
 15      context->state[2] = 0x98BADCFE;
 16      context->state[3] = 0x10325476;
 17 }
 18 void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen)
 19 {
 20     unsigned int i = 0,index = 0,partlen = 0;
 21     index = (context->count[0] >> 3) & 0x3F;
 22     partlen = 64 - index;
 23     context->count[0] += inputlen << 3;
 24     if(context->count[0] < (inputlen << 3))
 25        context->count[1]++;
 26     context->count[1] += inputlen >> 29;
 27     
 28     if(inputlen >= partlen)
 29     {
 30        memcpy(&context->buffer[index],input,partlen);
 31        MD5Transform(context->state,context->buffer);
 32        for(i = partlen;i+64 <= inputlen;i+=64)
 33            MD5Transform(context->state,&input[i]);
 34        index = 0;        
 35     }  
 36     else
 37     {
 38         i = 0;
 39     }
 40     memcpy(&context->buffer[index],&input[i],inputlen-i);
 41 }
 42 void MD5Final(MD5_CTX *context,unsigned char digest[16])
 43 {
 44     unsigned int index = 0,padlen = 0;
 45     unsigned char bits[8];
 46     index = (context->count[0] >> 3) & 0x3F;
 47     padlen = (index < 56)?(56-index):(120-index);
 48     MD5Encode(bits,context->count,8);
 49     MD5Update(context,PADDING,padlen);
 50     MD5Update(context,bits,8);
 51     MD5Encode(digest,context->state,16);
 52 }
 53 void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len)
 54 {
 55     unsigned int i = 0,j = 0;
 56     while(j < len)
 57     {
 58          output[j] = input[i] & 0xFF;  
 59          output[j+1] = (input[i] >> 8) & 0xFF;
 60          output[j+2] = (input[i] >> 16) & 0xFF;
 61          output[j+3] = (input[i] >> 24) & 0xFF;
 62          i++;
 63          j+=4;
 64     }
 65 }
 66 void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len)
 67 {
 68      unsigned int i = 0,j = 0;
 69      while(j < len)
 70      {
 71            output[i] = (input[j]) |
 72                        (input[j+1] << 8) |
 73                        (input[j+2] << 16) |
 74                        (input[j+3] << 24);
 75            i++;
 76            j+=4; 
 77      }
 78 }
 79 void MD5Transform(unsigned int state[4],unsigned char block[64])
 80 {
 81      unsigned int a = state[0];
 82      unsigned int b = state[1];
 83      unsigned int c = state[2];
 84      unsigned int d = state[3];
 85      unsigned int x[64];
 86      MD5Decode(x,block,64);
 87      FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */
 88  FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */
 89  FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */
 90  FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */
 91  FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */
 92  FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */
 93  FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */
 94  FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */
 95  FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */
 96  FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */
 97  FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
 98  FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
 99  FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
100  FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
101  FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
102  FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */
103  
104  /* Round 2 */
105  GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */
106  GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */
107  GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
108  GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */
109  GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */
110  GG(d, a, b, c, x[10], 9,  0x2441453); /* 22 */
111  GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */
112  GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */
113  GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */
114  GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */
115  GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */
116  GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */
117  GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */
118  GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */
119  GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */
120  GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */
121  
122  /* Round 3 */
123  HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */
124  HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */
125  HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */
126  HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */
127  HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */
128  HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */
129  HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */
130  HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */
131  HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */
132  HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */
133  HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */
134  HH(b, c, d, a, x[ 6], 23,  0x4881d05); /* 44 */
135  HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */
136  HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */
137  HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */
138  HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */
139  
140  /* Round 4 */
141  II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */
142  II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */
143  II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */
144  II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */
145  II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */
146  II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */
147  II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */
148  II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */
149  II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */
150  II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */
151  II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */
152  II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */
153  II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */
154  II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */
155  II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */
156  II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */
157      state[0] += a;
158      state[1] += b;
159      state[2] += c;
160      state[3] += d;
161 }

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <string.h>
 4 #include "md5.h"
 5 
 6 int main(int argc, char *argv[])
 7 {
 8     int i;
 9     unsigned char encrypt[] ="admin";//21232f297a57a5a743894a0e4a801fc3
10     unsigned char decrypt[16];    
11     MD5_CTX md5;
12     MD5Init(&md5);                 
13     MD5Update(&md5,encrypt,strlen((char *)encrypt));
14     MD5Final(&md5,decrypt);        
15     printf("加密前:%s\n加密后:",encrypt);
16     for(i=0;i<16;i++)
17     {
18         printf("%02x",decrypt[i]);
19     }
20     
21     getchar();
22     
23     return 0;
24 }