C/C++语言 MD5例子

之前研究了一下在C中进行MD5加密，由于找了很久没有找到现成的库文件，所以所幸自己去写了一下。个人感觉C的便捷性没有Python好的原因就是这里。

下面是我写的一个例子。

mian.cpp:

点击查看代码

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include "md5.c"

int main(int argc, char* argv[])

{
    int i;
    unsigned char encrypt[] = "admin";//21232f297a57a5a743894a0e4a801fc3
    unsigned char decrypt[16];
    MD5_CTX md5;
    MD5Init(&md5);
    MD5Update(&md5, encrypt, strlen((char*)encrypt));
    MD5Final(&md5, decrypt);
    printf("加密前:%s\n加密后:", encrypt);
    for (i = 0; i < 16; i++){
        printf("%02x", decrypt[i]);
        }
    getchar();
    return 0;

}

下面是上面引用的MD5.c

点击查看代码

#include <memory.h>

#include "md5.h"

unsigned char PADDING[] = { 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 };
void MD5Init(MD5_CTX* context){
    context->count[0] = 0;
    context->count[1] = 0;
    context->state[0] = 0x67452301;
    context->state[1] = 0xEFCDAB89;
    context->state[2] = 0x98BADCFE;
    context->state[3] = 0x10325476;
}

void MD5Update(MD5_CTX* context, unsigned char* input, unsigned int inputlen){
    unsigned int i = 0, index = 0, partlen = 0;
    index = (context->count[0] >> 3) & 0x3F;
    partlen = 64 - index;
    context->count[0] += inputlen << 3;
    if (context->count[0] < (inputlen << 3))
        context->count[1]++;
    context->count[1] += inputlen >> 29;
    if (inputlen >= partlen){
        memcpy(&context->buffer[index], input, partlen);
        MD5Transform(context->state, context->buffer);
        for (i = partlen; i + 64 <= inputlen; i += 64)
            MD5Transform(context->state, &input[i]);
        index = 0;
    }
    else{
        i = 0;
    }
    memcpy(&context->buffer[index], &input[i], inputlen - i);
}

void MD5Final(MD5_CTX* context, unsigned char digest[16])
{
    unsigned int index = 0, padlen = 0;
    unsigned char bits[8];
    index = (context->count[0] >> 3) & 0x3F;
    padlen = (index < 56) ? (56 - index) : (120 - index);
    MD5Encode(bits, context->count, 8);
    MD5Update(context, PADDING, padlen);
    MD5Update(context, bits, 8);
    MD5Encode(digest, context->state, 16);
}

void MD5Encode(unsigned char* output, unsigned int* input, unsigned int len)
{
    unsigned int i = 0, j = 0;
    while (j < len){
        output[j] = input[i] & 0xFF;
        output[j + 1] = (input[i] >> 8) & 0xFF;
        output[j + 2] = (input[i] >> 16) & 0xFF;
        output[j + 3] = (input[i] >> 24) & 0xFF;
        i++;
        j += 4;
    }
}

void MD5Decode(unsigned int* output, unsigned char* input, unsigned int len)
{
    unsigned int i = 0, j = 0;
    while (j < len){
        output[i] = (input[j]) |
            (input[j + 1] << 8) |
            (input[j + 2] << 16) |
            (input[j + 3] << 24);
        i++;
        j += 4;
    }

}

void MD5Transform(unsigned int state[4], unsigned char block[64])
{
    unsigned int a = state[0];
    unsigned int b = state[1];
    unsigned int c = state[2];
    unsigned int d = state[3];
    unsigned int x[64];
    MD5Decode(x, block, 64);
    FF(a, b, c, d, x[0], 7, 0xd76aa478); /* 1 */
    FF(d, a, b, c, x[1], 12, 0xe8c7b756); /* 2 */
    FF(c, d, a, b, x[2], 17, 0x242070db); /* 3 */
    FF(b, c, d, a, x[3], 22, 0xc1bdceee); /* 4 */
    FF(a, b, c, d, x[4], 7, 0xf57c0faf); /* 5 */
    FF(d, a, b, c, x[5], 12, 0x4787c62a); /* 6 */
    FF(c, d, a, b, x[6], 17, 0xa8304613); /* 7 */
    FF(b, c, d, a, x[7], 22, 0xfd469501); /* 8 */
    FF(a, b, c, d, x[8], 7, 0x698098d8); /* 9 */
    FF(d, a, b, c, x[9], 12, 0x8b44f7af); /* 10 */
    FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */
    FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */
    FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */
    FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */
    FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */
    FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */
    /* Round 2 */
    GG(a, b, c, d, x[1], 5, 0xf61e2562); /* 17 */
    GG(d, a, b, c, x[6], 9, 0xc040b340); /* 18 */
    GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */
    GG(b, c, d, a, x[0], 20, 0xe9b6c7aa); /* 20 */
    GG(a, b, c, d, x[5], 5, 0xd62f105d); /* 21 */

    GG(d, a, b, c, x[10], 9, 0x2441453); /* 22 */

    GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */

    GG(b, c, d, a, x[4], 20, 0xe7d3fbc8); /* 24 */

    GG(a, b, c, d, x[9], 5, 0x21e1cde6); /* 25 */

    GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */

    GG(c, d, a, b, x[3], 14, 0xf4d50d87); /* 27 */

    GG(b, c, d, a, x[8], 20, 0x455a14ed); /* 28 */

    GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */

    GG(d, a, b, c, x[2], 9, 0xfcefa3f8); /* 30 */

    GG(c, d, a, b, x[7], 14, 0x676f02d9); /* 31 */

    GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */

    /* Round 3 */

    HH(a, b, c, d, x[5], 4, 0xfffa3942); /* 33 */

    HH(d, a, b, c, x[8], 11, 0x8771f681); /* 34 */

    HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */

    HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */

    HH(a, b, c, d, x[1], 4, 0xa4beea44); /* 37 */

    HH(d, a, b, c, x[4], 11, 0x4bdecfa9); /* 38 */

    HH(c, d, a, b, x[7], 16, 0xf6bb4b60); /* 39 */

    HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */

    HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */

    HH(d, a, b, c, x[0], 11, 0xeaa127fa); /* 42 */

    HH(c, d, a, b, x[3], 16, 0xd4ef3085); /* 43 */

    HH(b, c, d, a, x[6], 23, 0x4881d05); /* 44 */

    HH(a, b, c, d, x[9], 4, 0xd9d4d039); /* 45 */

    HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */

    HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */

    HH(b, c, d, a, x[2], 23, 0xc4ac5665); /* 48 */

    /* Round 4 */

    II(a, b, c, d, x[0], 6, 0xf4292244); /* 49 */

    II(d, a, b, c, x[7], 10, 0x432aff97); /* 50 */

    II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */

    II(b, c, d, a, x[5], 21, 0xfc93a039); /* 52 */

    II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */

    II(d, a, b, c, x[3], 10, 0x8f0ccc92); /* 54 */

    II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */

    II(b, c, d, a, x[1], 21, 0x85845dd1); /* 56 */

    II(a, b, c, d, x[8], 6, 0x6fa87e4f); /* 57 */

    II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */

    II(c, d, a, b, x[6], 15, 0xa3014314); /* 59 */

    II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */

    II(a, b, c, d, x[4], 6, 0xf7537e82); /* 61 */

    II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */

    II(c, d, a, b, x[2], 15, 0x2ad7d2bb); /* 63 */

    II(b, c, d, a, x[9], 21, 0xeb86d391); /* 64 */

    state[0] += a;

    state[1] += b;

    state[2] += c;

    state[3] += d;

}

md5.h

#ifndef MD5_H

#define MD5_H

typedef struct

{

    unsigned int count[2];

    unsigned int state[4];

    unsigned char buffer[64];

}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[16]);
void MD5Transform(unsigned int state[4], unsigned char block[64]);
void MD5Encode(unsigned char* output, unsigned int* input, unsigned int len);
void MD5Decode(unsigned int* output, unsigned char* input, unsigned int len);
#endif

由此可在C语言中实现MD5的加密过程。