c++实现md5加密

最近发现md5加密算法挺有趣，特点是单向加密不可逆，加密后的字符串长度相等，于是就用C++尝试实现了一下

头文件定义

/********************************************************* brief: md5 encryption* author: Monkey.Knight********************************************************/#ifndef __MD5_ENCODE_H__#define __MD5_ENCODE_H__// std#include <string>// define#define UInt32 unsigned int#define BIT_OF_BYTE  8#define BIT_OF_GROUP 512#define SRC_DATA_LEN 64// 四个非线性函数宏定义#define DEF_F(X, Y, Z ) ((( (X) & (Y) )|((~X)&(Z))))#define DEF_G(X, Y, Z)  (((X)&(Z))|((Y)&(~Z)))#define DEF_H(X, Y, Z)  ((X)^(Y)^(Z))#define DEF_I(X, Y, Z)  ((Y)^((X)|(~Z)))// 求链接数函数宏定义#define FF(a, b, c, d, Mj, s, ti)  (a = b + CycleMoveLeft((a + DEF_F(b,c,d) + Mj + ti),s));#define GG(a, b, c, d, Mj, s, ti)  (a = b + CycleMoveLeft((a + DEF_G(b,c,d) + Mj + ti),s));#define HH(a, b, c, d, Mj, s, ti)  (a = b + CycleMoveLeft((a + DEF_H(b,c,d) + Mj + ti),s));#define II(a, b, c, d, Mj, s, ti)  (a = b + CycleMoveLeft((a + DEF_I(b,c,d) + Mj + ti),s));class Md5Encode {public:    // 4轮循环算法    struct ParamDynamic{        UInt32 ua_;        UInt32 ub_;        UInt32 uc_;        UInt32 ud_;    };public:    Md5Encode() {    }    std::string Encode(std::string src_info);    protected:    UInt32 CycleMoveLeft(UInt32 src_num, int bit_num_to_move);    UInt32 FillData(const char *in_data_ptr, int data_byte_len, char** out_data_ptr);    void RoundF(char *data_512_ptr, ParamDynamic & param);    void RoundG(char *data_512_ptr, ParamDynamic & param);    void RoundH(char *data_512_ptr, ParamDynamic & param);    void RoundI(char *data_512_ptr, ParamDynamic & param);    void RotationCalculate(char *data_512_ptr, ParamDynamic & param);    std::string GetHexStr(unsigned int num_str);private:    // 幻数定义    static const int kA;    static const int kB;    static const int kC;    static const int kD;    static const unsigned long long k_ti_num_integer;};#endif

源文件:

#include "md5_encode.h"#include <iostream>// 幻数定义const int Md5Encode::kA = 0x67452301;const int Md5Encode::kB = 0xefcdab89;const int Md5Encode::kC = 0x98badcfe;const int Md5Encode::kD = 0x10325476;const unsigned long long Md5Encode::k_ti_num_integer = 4294967296;// function: CycleMoveLeft// @param src_num:要左移的数// @param bit_num_to_move:要移动的bit位数// @return  循环左移后的结果数UInt32 Md5Encode::CycleMoveLeft(UInt32 src_num, int bit_num_to_move) {    if (0 >= bit_num_to_move) {        return src_num;    }    return ((src_num << bit_num_to_move) \        | (src_num >> (32 - bit_num_to_move)));}// function: FillData// @param in_data_ptr:    要加密的信息数据// @param data_byte_len: 数据的字节数// @param out_data_ptr:  填充必要信息后的数据// return : 填充信息后的数据长度,以字节为单位UInt32 Md5Encode::FillData(const char *in_data_ptr, int data_byte_len, char** out_data_ptr) {    int bit_num = data_byte_len*BIT_OF_BYTE;    int grop_num = bit_num / BIT_OF_GROUP;    int mod_bit_num = bit_num % BIT_OF_GROUP;    int bit_need_fill = 0;    if (mod_bit_num > (BIT_OF_GROUP -  SRC_DATA_LEN)) {        bit_need_fill = (BIT_OF_GROUP - mod_bit_num);        bit_need_fill += (BIT_OF_GROUP -  SRC_DATA_LEN);    }    else {        bit_need_fill = (BIT_OF_GROUP -  SRC_DATA_LEN) - mod_bit_num; //  这里多加了一个BIT_OF_GROUP，避免bit_need_fill正好等于0,暂时不加    }    int all_bit = bit_num + bit_need_fill;    if (0 < bit_need_fill) {        *out_data_ptr = new char[all_bit / BIT_OF_BYTE + SRC_DATA_LEN / BIT_OF_BYTE];        memset(*out_data_ptr, 0, all_bit / BIT_OF_BYTE + SRC_DATA_LEN / BIT_OF_BYTE);        // copy data        memcpy(*out_data_ptr, in_data_ptr, data_byte_len);        // fill rest data        unsigned char *tmp = reinterpret_cast<unsigned char *>(*out_data_ptr);        tmp += data_byte_len;        // fill 1 and 0        *tmp = 0x80;        // fill origin data len        unsigned long long * origin_num = (unsigned long long *)((*out_data_ptr) + ((all_bit / BIT_OF_BYTE)));        *origin_num = data_byte_len*BIT_OF_BYTE;    }    return (all_bit / BIT_OF_BYTE + SRC_DATA_LEN / BIT_OF_BYTE);}void Md5Encode::RoundF(char *data_BIT_OF_GROUP_ptr, ParamDynamic & param) {    UInt32 *M = reinterpret_cast<UInt32*>(data_BIT_OF_GROUP_ptr);    int s[] = { 7, 12, 17, 22 };    for (int i = 0; i < 16; ++i) {        UInt32 ti = k_ti_num_integer * abs(sin(i + 1));        if (i % 4 == 0) {            FF(param.ua_, param.ub_, param.uc_, param.ud_, M[i], s[i % 4], ti);        }        else if (i % 4 == 1) {            FF(param.ud_, param.ua_, param.ub_, param.uc_, M[i], s[i % 4], ti);        }        else if (i % 4 == 2) {            FF(param.uc_, param.ud_, param.ua_, param.ub_, M[i], s[i % 4], ti);        }        else if (i % 4 == 3) {            FF(param.ub_, param.uc_, param.ud_, param.ua_, M[i], s[i % 4], ti);        }    }}void Md5Encode::RoundG(char *data_BIT_OF_GROUP_ptr, ParamDynamic & param) {    UInt32 *M = reinterpret_cast<UInt32*>(data_BIT_OF_GROUP_ptr);    int s[] = { 5, 9, 14, 20 };    for (int i = 0; i < 16; ++i) {        UInt32 ti = k_ti_num_integer * abs(sin(i + 1 + 16));        int index = (i * 5 + 1) % 16;        if (i % 4 == 0) {            GG(param.ua_, param.ub_, param.uc_, param.ud_, M[index], s[i % 4], ti);        }        else if (i % 4 == 1) {            GG(param.ud_, param.ua_, param.ub_, param.uc_, M[index], s[i % 4], ti);        }        else if (i % 4 == 2) {            GG(param.uc_, param.ud_, param.ua_, param.ub_, M[index], s[i % 4], ti);        }        else if (i % 4 == 3) {            GG(param.ub_, param.uc_, param.ud_, param.ua_, M[index], s[i % 4], ti);        }    }}void Md5Encode::RoundH(char *data_BIT_OF_GROUP_ptr, ParamDynamic & param) {    UInt32 *M = reinterpret_cast<UInt32*>(data_BIT_OF_GROUP_ptr);    int s[] = { 4, 11, 16, 23 };    for (int i = 0; i < 16; ++i) {        UInt32 ti = k_ti_num_integer * abs(sin(i + 1 + 32));        int index = (i * 3 + 5) % 16;        if (i % 4 == 0) {            HH(param.ua_, param.ub_, param.uc_, param.ud_, M[index], s[i % 4], ti);        }        else if (i % 4 == 1) {            HH(param.ud_, param.ua_, param.ub_, param.uc_, M[index], s[i % 4], ti);        }        else if (i % 4 == 2) {            HH(param.uc_, param.ud_, param.ua_, param.ub_, M[index], s[i % 4], ti);        }        else if (i % 4 == 3) {            HH(param.ub_, param.uc_, param.ud_, param.ua_, M[index], s[i % 4], ti);        }    }}void Md5Encode::RoundI(char *data_BIT_OF_GROUP_ptr, ParamDynamic & param) {    UInt32 *M = reinterpret_cast<UInt32*>(data_BIT_OF_GROUP_ptr);    int s[] = { 6, 10, 15, 21 };    for (int i = 0; i < 16; ++i) {        UInt32 ti = k_ti_num_integer * abs(sin(i + 1 + 48));        int index = (i * 7 + 0) % 16;        if (i % 4 == 0) {            II(param.ua_, param.ub_, param.uc_, param.ud_, M[index], s[i % 4], ti);        }        else if (i % 4 == 1) {            II(param.ud_, param.ua_, param.ub_, param.uc_, M[index], s[i % 4], ti);        }        else if (i % 4 == 2) {            II(param.uc_, param.ud_, param.ua_, param.ub_, M[index], s[i % 4], ti);        }        else if (i % 4 == 3) {            II(param.ub_, param.uc_, param.ud_, param.ua_, M[index], s[i % 4], ti);        }    }}void Md5Encode::RotationCalculate(char *data_512_ptr, ParamDynamic & param) {    if (NULL == data_512_ptr) {        return;    }    RoundF(data_512_ptr, param);    RoundG(data_512_ptr, param);    RoundH(data_512_ptr, param);    RoundI(data_512_ptr, param);    param.ua_ = kA + param.ua_;    param.ub_ = kB + param.ub_;    param.uc_ = kC + param.uc_;    param.ud_ = kD + param.ud_;}// 转换成十六进制字符串输出std::string Md5Encode::GetHexStr(unsigned int num_str) {    std::string hexstr = "";    char szch[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };    unsigned char *tmptr = (unsigned char *)&num_str;    int len = sizeof(num_str);    // 小端字节序，逆序打印    for (int i = 0; i < len; i++){        unsigned char ch = tmptr[i] & 0xF0;        ch = ch >> 4;        hexstr.append(1, szch[ch]);        ch = tmptr[i] & 0x0F;        hexstr.append(1, szch[ch]);    }    return hexstr;}// function: Encode// @param src_info:要加密的信息// return :加密后的MD5值std::string Md5Encode::Encode(std::string src_info) {    ParamDynamic param;    param.ua_ = kA;    param.ub_ = kB;    param.uc_ = kC;    param.ud_ = kD;    std::string result;    const char *src_data = src_info.c_str();    char *out_data_ptr = NULL;    int total_byte = FillData(src_data, strlen(src_data), &out_data_ptr);    char * data_BIT_OF_GROUP = out_data_ptr;    for (int i = 0; i < total_byte / (BIT_OF_GROUP / BIT_OF_BYTE); ++i) {        data_BIT_OF_GROUP += i*(BIT_OF_GROUP / BIT_OF_BYTE);        RotationCalculate(data_BIT_OF_GROUP, param);    }    if (NULL != out_data_ptr) {        delete[] out_data_ptr, out_data_ptr =  NULL;    }        result.append(GetHexStr(param.ua_));    result.append(GetHexStr(param.ub_));    result.append(GetHexStr(param.uc_));    result.append(GetHexStr(param.ud_));    return result;}

测试：

#include <iostream>#include <cmath>#include "md5_encode.h"int main(int argc, char* argv[]) {    std::string src = "fasdfasdfasdfnmmw,enrsudfnsmndfejkjhuasdmnf";    Md5Encode encode_obj;    std::string ret = encode_obj.Encode(src);    std::cout << "info: " << src.c_str() << std::endl;    std::cout << "md5: " << ret.c_str() << std::endl;    return 0;}

结果：

info: fasdfasdfasdfnmmw,enrsudfnsmndfejkjhuasdmnf
md5: 01109ec97162a71ca5e67b5f059c3cac