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  • MD5摘要算法实现

    网上找到的实现md5函数代码,包括一个头文件md5.h和一个源文件md5.c,用下面的测试代码test.c测试通过,各文件依次如下:

    头文件md5.h:

     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
    View Code

    源文件md5.c:

      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 }
    View Code

    测试代码test.c:

     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
    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 }
    View Code
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  • 原文地址:https://www.cnblogs.com/jiu0821/p/4395738.html
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