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c++实现md5加密

原作者: [db:作者] 来自: [db:来源] 收藏 邀请

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


 1 /*
 2 *******************************************************
 3 * brief: md5 encryption
 4 * author: Monkey.Knight
 5 *******************************************************
 6 */
 7 
 8 #ifndef __MD5_ENCODE_H__
 9 #define __MD5_ENCODE_H__
10 
11 // std
12 #include <string>
13 
14 // define
15 #define UInt32 unsigned int
16 #define BIT_OF_BYTE  8
17 #define BIT_OF_GROUP 512
18 #define SRC_DATA_LEN 64
19 
20 // 四个非线性函数宏定义
21 #define DEF_F(X, Y, Z ) ((( (X) & (Y) )|((~X)&(Z))))
22 #define DEF_G(X, Y, Z)  (((X)&(Z))|((Y)&(~Z)))
23 #define DEF_H(X, Y, Z)  ((X)^(Y)^(Z))
24 #define DEF_I(X, Y, Z)  ((Y)^((X)|(~Z)))
25 
26 // 求链接数函数宏定义
27 #define FF(a, b, c, d, Mj, s, ti)  (a = b + CycleMoveLeft((a + DEF_F(b,c,d) + Mj + ti),s));
28 #define GG(a, b, c, d, Mj, s, ti)  (a = b + CycleMoveLeft((a + DEF_G(b,c,d) + Mj + ti),s));
29 #define HH(a, b, c, d, Mj, s, ti)  (a = b + CycleMoveLeft((a + DEF_H(b,c,d) + Mj + ti),s));
30 #define II(a, b, c, d, Mj, s, ti)  (a = b + CycleMoveLeft((a + DEF_I(b,c,d) + Mj + ti),s));
31 
32 
33 class Md5Encode {
34 public:
35     // 4轮循环算法
36     struct ParamDynamic{
37         UInt32 ua_;
38         UInt32 ub_;
39         UInt32 uc_;
40         UInt32 ud_;
41         UInt32 va_last_;
42         UInt32 vb_last_;
43         UInt32 vc_last_;
44         UInt32 vd_last_;
45     };
46 public:
47     Md5Encode() {
48     }
49     std::string Encode(std::string src_info);
50 
51 protected:
52     
53     UInt32 CycleMoveLeft(UInt32 src_num, int bit_num_to_move);
54     UInt32 FillData(const char *in_data_ptr, int data_byte_len, char** out_data_ptr);
55     void RoundF(char *data_512_ptr, ParamDynamic & param);
56     void RoundG(char *data_512_ptr, ParamDynamic & param);
57     void RoundH(char *data_512_ptr, ParamDynamic & param);
58     void RoundI(char *data_512_ptr, ParamDynamic & param);
59     void RotationCalculate(char *data_512_ptr, ParamDynamic & param);
60     std::string GetHexStr(unsigned int num_str);
61     
62 private:
63     // 幻数定义
64     static const int kA;
65     static const int kB;
66     static const int kC;
67     static const int kD;
68     static const unsigned long long k_ti_num_integer;
69 };
70 
71 #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) {
    UInt32 src_num1 = src_num;
    UInt32 src_num2 = src_num;
    if (0 >= bit_num_to_move) {
        return src_num;
    }
    UInt32 num1 = src_num1 << bit_num_to_move;
    UInt32 num2 = src_num2 >> (32 - bit_num_to_move);
    
    return ((src_num1 << bit_num_to_move) \
        | (src_num2 >> (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_ = param.va_last_ + param.ua_;
    param.ub_ = param.vb_last_ + param.ub_;
    param.uc_ = param.vc_last_ + param.uc_;
    param.ud_ = param.vd_last_ + param.ud_;
    
    param.va_last_ = param.ua_;
    param.vb_last_ = param.ub_;
    param.vc_last_ = param.uc_;
    param.vd_last_ = 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;
    param.va_last_ = kA;
    param.vb_last_ = kB;
    param.vc_last_ = kC;
    param.vd_last_ = 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) {
        char * data_BIT_OF_GROUP = out_data_ptr;
        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


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