md5

1. 附加填充位
 　首先对输入的报文进行填位补充,使填充后的数据长度模512后余448.
   如果数据长度正好模512余448,则需增加512个填充位,也就是说填充的个数为1~512位.
   填充位第一个位为1,其余全部为0.

2. 补足长度
   将数据长度表示为二进制,如果长度超过64位,则截取其低64位;
   如果长度不足64位,则在其高位补0.
   将这个64位的报文长度补在经过填充的报文后面,使得最后的数据为512位的整数倍.

3. 初始化MD缓存器
   MD5运算要用到一个128位的MD5缓存器,用来保存中间变量和最终结果.
   该缓存器又可看成是4个32位的寄存器A、B、C、D,初始化为:
   A: 01 23 45 67
   B: 89 ab cd ef
   C: fe dc ba 98
   D: 76 54 32 10

4. 处理数据段
   首先定义4个非线性函数F、G、H、I, 对输入的报文运算以512位数据段为单位进行处理.
   对每个数据段都要进行4轮的逻辑处理,在4轮中分别使用4个不同的函数F、G、H、I.
   每一轮以ABCD和当前的512位的块为输入,处理后送入ABCD(128位)

* md5.h

//
//  md5.h
//  md5
//
//  Created by 晨辉明 on 2019/8/11.
//  Copyright © 2019 晨辉明. All rights reserved.
//

#ifndef md5_h
#define md5_h

#include <iostream>

// 右移的时候，高位一定要补零，而不是补充符号位
#define shift(x, n) (((x) << (n)) | ((x) >> (32-(n))))
#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)))
/**
 * MD5运算要用到一个128位的MD5缓存器,用来保存中间变量和最终结果.该缓存器又可看成是4个32位的寄存器A、B、C、D,初始化为:
 * A: 01 23 45 67
 * B：89 ab cd ef
 * C：fe dc ba 98
 * D：76 54 32 10
 */
#define A 0x67452301
#define B 0xefcdab89
#define C 0x98badcfe
#define D 0x10325476

void mainLoop(unsigned int M[]);

unsigned int* add(std::string str);
std::string changeHex(int a);
std::string getMD5(std::string source);

#endif /* md5_h */

用php生成常亮数组表:

<?php

class Consts {
    private static function getOne($i) {
//        $a = sin(1)* pow(2, 32);
        return floor( abs(sin($i+1)) * pow(2, 32));
    }

    const INDENT = "  ";
    const EOL = "\n";

    public static function main() {
        printf("const k = {".self::EOL);
        printf(self::INDENT);
        for ($i = 0; $i < 4; $i++) {
            printf("0x%08x,", self::getOne($i));
        }
        printf(self::EOL);

        $j = 0;
        printf(self::INDENT);
        for ($i = 4; $i < 63; $i++) {
            printf("0x%08x,", self::getOne($i));
            $j++;
            if ($j == 5) {
                printf(self::EOL);
                $j = 0;
                printf(self::INDENT);
            }
        }
        printf("0x%08x%s", self::getOne($i), self::EOL);
        printf("};");
    }
}

Consts::main();

php Consts.php

 

* md5.cpp

//
//  md5.cpp
//  md5
//
//  Created by 晨辉明 on 2019/8/11.
//  Copyright © 2019 晨辉明. All rights reserved.
//

#include "md5.h"
#include <iomanip>

using std::string;

//strBaye的长度
unsigned long strlength;
//A,B,C,D的临时变量
unsigned int atemp;
unsigned int btemp;
unsigned int ctemp;
unsigned int dtemp;
//常量ti unsigned int(abs(sin(i+1))*(2pow32))
const unsigned int k[]={
    0xd76aa478,0xe8c7b756,0x242070db,0xc1bdceee,
    0xf57c0faf,0x4787c62a,0xa8304613,0xfd469501,0x698098d8,
    0x8b44f7af,0xffff5bb1,0x895cd7be,0x6b901122,0xfd987193,
    0xa679438e,0x49b40821,0xf61e2562,0xc040b340,0x265e5a51,
    0xe9b6c7aa,0xd62f105d,0x02441453,0xd8a1e681,0xe7d3fbc8,
    0x21e1cde6,0xc33707d6,0xf4d50d87,0x455a14ed,0xa9e3e905,
    0xfcefa3f8,0x676f02d9,0x8d2a4c8a,0xfffa3942,0x8771f681,
    0x6d9d6122,0xfde5380c,0xa4beea44,0x4bdecfa9,0xf6bb4b60,
    0xbebfbc70,0x289b7ec6,0xeaa127fa,0xd4ef3085,0x04881d05,
    0xd9d4d039,0xe6db99e5,0x1fa27cf8,0xc4ac5665,0xf4292244,
    0x432aff97,0xab9423a7,0xfc93a039,0x655b59c3,0x8f0ccc92,
    0xffeff47d,0x85845dd1,0x6fa87e4f,0xfe2ce6e0,0xa3014314,
    0x4e0811a1,0xf7537e82,0xbd3af235,0x2ad7d2bb,0xeb86d391};
//向左位移数
const unsigned int s[]={7,12,17,22,7,12,17,22,7,12,17,22,7,
    12,17,22,5,9,14,20,5,9,14,20,5,9,14,20,5,9,14,20,
    4,11,16,23,4,11,16,23,4,11,16,23,4,11,16,23,6,10,
    15,21,6,10,15,21,6,10,15,21,6,10,15,21};
const char str16[]="0123456789abcdef";

int printf(const char *, ...);

void mainLoop(unsigned int M[])
{
    unsigned int f,g;
    unsigned int a=atemp;
    unsigned int b=btemp;
    unsigned int c=ctemp;
    unsigned int d=dtemp;
    // printf("a=0x%08x, b=0x%08x, c=0x%08x, d=0x%08x\n", a, b, c, d);
    
    for (unsigned int i = 0; i < 64; i++)
    {
        if(i<16){
            f=F(b,c,d);
            printf("f=0x%08x\n", f);
            g=i;
        }else if (i<32) {
            // printf("b=0x%08x, c=0x%08x, d = 0x%08x, ", b, c, d);
            f=G(b,c,d);
            g=(5*i+1)%16;
        }else if(i<48){
            f=H(b,c,d);
            g=(3*i+5)%16;
        }else{
            f=I(b,c,d);
            g=(7*i)%16;
        }
        unsigned int tmp=d;
        d=c;
        c=b;
        
        // printf("a=0x%08x, f=0x%08x, k[i]=0x%08x, g=0x%08x, m[g]=0x%08x\n", a, f, k[i], g, M[g]);
        // printf("shift x=0x%08x, n=%d\n", (a+f+k[i]+M[g]), s[i] );
        b = b + shift((a+f+k[i]+M[g]), s[i]);
        // printf("after b=0x%08x\n", b);
        a=tmp;
    }
    atemp=a+atemp;
    btemp=b+btemp;
    ctemp=c+ctemp;
    dtemp=d+dtemp;
    printf("a=0x%08x, b=0x%08x, c=0x%08x, d=0x%08x\n", a, b, c, d);
}
/*
 *填充函数
 *处理后应满足bits≡448(mod512),字节就是bytes≡56（mode64)
 *填充方式为先加一个1,其它位补零
 *最后加上64位的原来长度
 */
unsigned int* add(string str)
{
    unsigned long num=((str.length()+8)/64)+1;         //以512位,64个字节为一组
    unsigned int *strByte = new unsigned int[num*16];    //64/4=16,所以有16个整数
    strlength = num*16;
    for (unsigned int i = 0; i < num*16; i++)
        strByte[i]=0;
    for (unsigned int i=0; i <str.length(); i++) {
        // 一个整数存储四个字节，i>>2表示i/4 一个unsigned int对应4个字节，保存4个字符信息
        strByte[i>>2]|=(str[i])<<((i%4)*8);
    }
    
    //尾部添加1 一个unsigned int保存4个字符信息,所以用128左移
    strByte[str.length()>>2]|=0x80<<(((str.length()%4))*8);
    /*
     *添加原长度，长度指位的长度，所以要乘8，然后是小端序，所以放在倒数第二个,这里长度只用了32位
     */
    strByte[num*16-2] = (unsigned int)str.length() * 8;
    return strByte;
}
string changeHex(int a)
{
    int b;
    string str1;
    string str="";
    for(int i=0;i<4;i++)
    {
        str1="";
        b=((a>>i*8)%(1<<8))&0xff;   //逆序处理每个字节
        for (int j = 0; j < 2; j++)
        {
            str1.insert(0, 1, str16[b%16]);
            b=b/16;
        }
        str+=str1;
    }
    return str;
}
string getMD5(string source)
{
    atemp=A;    //初始化
    btemp=B;
    ctemp=C;
    dtemp=D;
    unsigned int *strByte=add(source);
    for(unsigned int i=0;i<strlength/16;i++)
    {
        unsigned int num[16];
        for(unsigned int j=0;j<16;j++) {
            num[j] = strByte[i*16+j];
        }
        for (int k = 0; k < 16; k++) {
            std::cout << num[k] << ",";
        }
        std::cout << std::endl;
        mainLoop(num);
    }
    return changeHex(atemp).append(changeHex(btemp)).append(changeHex(ctemp)).append(changeHex(dtemp));
}

* main.cpp

//
//  main.cpp
//  md5
//
//  Created by 晨辉明 on 2019/8/11.
//  Copyright © 2019 晨辉明. All rights reserved.
//

#include <iostream>
#include "md5.h"

using std::string;
using std::cout;
using std::endl;

int main(int argc, const char * argv[]) {
    string ss;
    string s = getMD5("abc1234567890");
    cout << s << endl;
    return 0;
}