C/C++: MD5编码

在程序编写过程中，很多时候会用到数据校验，MD5则是一个很方便的校验方式，下面就是MD5的实现方法。

1、头文件MD5.h

#ifndef MD5_H  #define MD5_H  #include <string>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 TYPE_16     1#define TYPE_32     2#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; \}class MD5 {public:    MD5() {        ctx = new MD5_CTX();    };    ~MD5() {        delete 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]);    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);    std::string Md5Encrypt(std::string input);    std::string Md5Encrypt(std::string input, int type);    MD5_CTX *ctx;};#endif

2、实现MD5.cpp

#include <string.h>#include "DXT_MD5_16_32.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 MD5::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 MD5::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 MD5::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 MD5::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 MD5::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 MD5::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;}std::string MD5::Md5Encrypt(std::string input) {    MD5Init(ctx);    int length = input.length();    //编码    unsigned char encrypt[16];    MD5Update(ctx, (unsigned char*)input.c_str(), length);    MD5Final(ctx, encrypt);    std::string ss_16 = "";    for (int i = 4; i < 12; i++)    {        char tmp[16];        sprintf(tmp, "%02x", encrypt[i]);        ss_16.append(tmp);    }    return ss_16;}std::string MD5::Md5Encrypt(std::string input, int type) {    MD5Init(ctx);    int length = input.length();    //编码    unsigned char encrypt[16];    MD5Update(ctx, (unsigned char*)input.c_str(), length);    MD5Final(ctx, encrypt);    std::string str = "";    if (type == TYPE_16) {        for (int i = 4; i < 12; i++)        {            char tmp[16];            sprintf(tmp, "%02x", encrypt[i]);            str.append(tmp);        }        return str;    }    if (type == TYPE_32) {        for (int i = 0; i < 16; i++)        {            char tmp[32];            sprintf(tmp, "%02x", encrypt[i]);            str.append(tmp);        }        return str;    }    return nullptr;}

3、使用方法

    //传入Data数据，选择是16位还是32位    MD5 *md5 = new MD5();    log("md5 = %s", md5->Md5Encrypt(Data, TYPE_32).c_str());    log("md5 = %s", md5->Md5Encrypt(Data, TYPE_16).c_str());

4、下载地址

MD5编码