C 语言

关注公众号 jb51net

关闭
首页 > 软件编程 > C 语言 > c语言实现MD5算法

c语言实现MD5算法的项目实践

作者:hs977986979

MD5用于确保信息传输完整一致,是计算机广泛使用的杂凑算法之一,本文主要介绍了c语言实现MD5算法,具有一定的参考价值,感兴趣的可以了解一下

MD5介绍

 1。 一种单向加密算法,即对明文加密,而不能通过密文得到明文。对原数据的任何改动,哪怕是1字节,得到的MD5值都有很大的区别。可以用公式表示:密文=Md5_calc(原文数据);

应用场景

1.密码认证;
2.数据校验:

代码分析 (基于qt5.14.2)

md5.c

#include <string.h>
#include "md5.h"
#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 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);
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);
    FF(d, a, b, c, x[ 1], 12, 0xe8c7b756);
    FF(c, d, a, b, x[ 2], 17, 0x242070db);
    FF(b, c, d, a, x[ 3], 22, 0xc1bdceee);
    FF(a, b, c, d, x[ 4], 7, 0xf57c0faf);
    FF(d, a, b, c, x[ 5], 12, 0x4787c62a);
    FF(c, d, a, b, x[ 6], 17, 0xa8304613);
    FF(b, c, d, a, x[ 7], 22, 0xfd469501);
    FF(a, b, c, d, x[ 8], 7, 0x698098d8);
    FF(d, a, b, c, x[ 9], 12, 0x8b44f7af);
    FF(c, d, a, b, x[10], 17, 0xffff5bb1);
    FF(b, c, d, a, x[11], 22, 0x895cd7be);
    FF(a, b, c, d, x[12], 7, 0x6b901122);
    FF(d, a, b, c, x[13], 12, 0xfd987193);
    FF(c, d, a, b, x[14], 17, 0xa679438e);
    FF(b, c, d, a, x[15], 22, 0x49b40821);
    GG(a, b, c, d, x[ 1], 5, 0xf61e2562);
    GG(d, a, b, c, x[ 6], 9, 0xc040b340);
    GG(c, d, a, b, x[11], 14, 0x265e5a51);
    GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa);
    GG(a, b, c, d, x[ 5], 5, 0xd62f105d);
    GG(d, a, b, c, x[10], 9,  0x2441453);
    GG(c, d, a, b, x[15], 14, 0xd8a1e681);
    GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8);
    GG(a, b, c, d, x[ 9], 5, 0x21e1cde6);
    GG(d, a, b, c, x[14], 9, 0xc33707d6);
    GG(c, d, a, b, x[ 3], 14, 0xf4d50d87);
    GG(b, c, d, a, x[ 8], 20, 0x455a14ed);
    GG(a, b, c, d, x[13], 5, 0xa9e3e905);
    GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8);
    GG(c, d, a, b, x[ 7], 14, 0x676f02d9);
    GG(b, c, d, a, x[12], 20, 0x8d2a4c8a);
    HH(a, b, c, d, x[ 5], 4, 0xfffa3942);
    HH(d, a, b, c, x[ 8], 11, 0x8771f681);
    HH(c, d, a, b, x[11], 16, 0x6d9d6122);
    HH(b, c, d, a, x[14], 23, 0xfde5380c);
    HH(a, b, c, d, x[ 1], 4, 0xa4beea44);
    HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9);
    HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60);
    HH(b, c, d, a, x[10], 23, 0xbebfbc70);
    HH(a, b, c, d, x[13], 4, 0x289b7ec6);
    HH(d, a, b, c, x[ 0], 11, 0xeaa127fa);
    HH(c, d, a, b, x[ 3], 16, 0xd4ef3085);
    HH(b, c, d, a, x[ 6], 23,  0x4881d05);
    HH(a, b, c, d, x[ 9], 4, 0xd9d4d039);
    HH(d, a, b, c, x[12], 11, 0xe6db99e5);
    HH(c, d, a, b, x[15], 16, 0x1fa27cf8);
    HH(b, c, d, a, x[ 2], 23, 0xc4ac5665);
    II(a, b, c, d, x[ 0], 6, 0xf4292244);
    II(d, a, b, c, x[ 7], 10, 0x432aff97);
    II(c, d, a, b, x[14], 15, 0xab9423a7);
    II(b, c, d, a, x[ 5], 21, 0xfc93a039);
    II(a, b, c, d, x[12], 6, 0x655b59c3);
    II(d, a, b, c, x[ 3], 10, 0x8f0ccc92);
    II(c, d, a, b, x[10], 15, 0xffeff47d);
    II(b, c, d, a, x[ 1], 21, 0x85845dd1);
    II(a, b, c, d, x[ 8], 6, 0x6fa87e4f);
    II(d, a, b, c, x[15], 10, 0xfe2ce6e0);
    II(c, d, a, b, x[ 6], 15, 0xa3014314);
    II(b, c, d, a, x[13], 21, 0x4e0811a1);
    II(a, b, c, d, x[ 4], 6, 0xf7537e82);
    II(d, a, b, c, x[11], 10, 0xbd3af235);
    II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb);
    II(b, c, d, a, x[ 9], 21, 0xeb86d391);
    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;
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]);
#endif

main.c

#include <QCoreApplication>
extern "C"{         //添加头文件
    #include "md5.h"
}
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    int i, n;
    bool isfile = false;
    unsigned char decrypt[16];
    MD5_CTX md5;
    if(argc > 1 && strlen(argv[1]) == 2 && !memcmp(argv[1], "-f", 2)) {
        isfile = true;
    }
    if(argc == 1 || (argc == 2 && isfile)) {
        fprintf(stderr, "usage:\n    %s -f file ...\n    %s string ...\n", argv[0], argv[0]);
        return 1;
    }
    if(isfile) {
        FILE *fp;
        for(n=2; n<argc; n++) {
            fp = fopen(argv[n], "rb");
            if(fp == NULL) {
                fprintf(stderr, "File %s not exists, errno = %d, error = %s\n", argv[n], errno, strerror(errno));
                continue;
            }
            MD5Init(&md5);
            do {
                unsigned char encrypt[1024];
                while(!feof(fp)) {
                    MD5Update(&md5, encrypt, fread(encrypt, 1, sizeof(encrypt), fp));
                }
                fclose(fp);
            } while(0);
            MD5Final(&md5, decrypt);
            for(i=0; i<16; i++) {
                printf("%02x", decrypt[i]);  //02x前需要加上 %
            }
            printf("  %s\n", argv[n]);
        }
    } else {
        for(n=1; n<argc; n++) {
            MD5Init(&md5);
            MD5Update(&md5,(unsigned char*) argv[n], strlen(argv[n]));
            MD5Final(&md5, decrypt);
            for(i=0; i<16; i++) {
                printf("%02x", decrypt[i]);  //02x前需要加上 %
            }
            printf("  %s\n", argv[n]);
        }
    }
    return a.exec();
}

测试记录 源码打包(windeployqt.exe工具),得到MD5.exe

运行测试,创建一个test.txt文件,打开文件写入:123,保存关闭,运行如下测试命令:MD5.exe -f test.txt 得到密文:202cb962ac59075b964b07152d234b70

测试准确性,利用在线工具,输入:123得到相同的密文,验证成功。

到此这篇关于c语言实现MD5算法的项目实践的文章就介绍到这了,更多相关c语言实现MD5算法内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!

您可能感兴趣的文章:
阅读全文