md5加密算法

MD5.h

#ifndef MD5H
#define MD5H
#include <math.h>
#include <Windows.h>

void ROL(unsigned int &s, unsigned short cx); //32位数循环左移实现函数
void ltob(unsigned int &i); //B\L互转，接受UINT类型
unsigned int* MD5(const char* mStr); //接口函数，并执行数据填充，计算MD5时调用此函数

#endif

MD5.cpp

#include "MD5.h"

/*4组计算函数*/
inline unsigned int F(unsigned int X, unsigned int Y, unsigned int Z)
{
	return (X & Y) | ((~X) & Z);
}
inline unsigned int G(unsigned int X, unsigned int Y, unsigned int Z)
{
	return (X & Z) | (Y & (~Z));
}
inline unsigned int H(unsigned int X, unsigned int Y, unsigned int Z)
{
	return X ^ Y ^ Z;
}
inline unsigned int I(unsigned int X, unsigned int Y, unsigned int Z)
{
	return Y ^ (X | (~Z));
}
/*4组计算函数结束*/

/*32位数循环左移实现函数*/
void ROL(unsigned int &s, unsigned short cx)
{
	if (cx > 32)cx %= 32;
	s = (s << cx) | (s >> (32 - cx));
	return;
}

/*B\L互转，接收UINT类型*/
void ltob(unsigned int &i)
{
	unsigned int tmp = i;//保存副本
	byte *psour = (byte*)&tmp, *pdes = (byte*)&i;
	pdes += 3;//调整指针，准备左右调转
	for (short i = 3; i >= 0; --i)
	{
		CopyMemory(pdes - i, psour + i, 1);
	}
	return;
}

/*
MD5循环计算函数，label=第几轮循环（1<=label<=4），lGroup数组=4个种子副本，M=数据（16组32位数指针）
种子数组排列方式: --A--D--C--B--，即 lGroup[0]=A; lGroup[1]=D; lGroup[2]=C; lGroup[3]=B;
*/
void AccLoop(unsigned short label, unsigned int *lGroup, void *M)
{
	unsigned int *i1, *i2, *i3, *i4, TAcc, tmpi = 0; //定义:4个指针； T表累加器； 局部变量
	typedef unsigned int(*clac)(unsigned int X, unsigned int Y, unsigned int Z); //定义函数类型
	const unsigned int rolarray[4][4] = {
		{ 7, 12, 17, 22 },
		{ 5, 9, 14, 20 },
		{ 4, 11, 16, 23 },
		{ 6, 10, 15, 21 }
	};//循环左移-位数表
	const unsigned short mN[4][16] = {
		{ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 },
		{ 1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12 },
		{ 5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2 },
		{ 0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9 }
	};//数据坐标表
	const unsigned int *pM = static_cast<unsigned int*>(M);//转换类型为32位的Uint
	TAcc = ((label - 1) * 16) + 1; //根据第几轮循环初始化T表累加器
	clac clacArr[4] = { F, G, H, I }; //定义并初始化计算函数指针数组

	/*一轮循环开始（16组->16次）*/
	for (short i = 0; i < 16; ++i)
	{
		/*进行指针自变换*/
		i1 = lGroup + ((0 + i) % 4);
		i2 = lGroup + ((3 + i) % 4);
		i3 = lGroup + ((2 + i) % 4);
		i4 = lGroup + ((1 + i) % 4);

		/*第一步计算开始: A+F(B,C,D)+M[i]+T[i+1] 注:第一步中直接计算T表*/
		tmpi = (*i1 + clacArr[label - 1](*i2, *i3, *i4) + pM[(mN[label - 1][i])] + (unsigned int)(0x100000000UL * abs(sin((double)(TAcc + i)))));
		ROL(tmpi, rolarray[label - 1][i % 4]);//第二步:循环左移
		*i1 = *i2 + tmpi;//第三步:相加并赋值到种子
	}
	return;
}

/*接口函数，并执行数据填充*/
unsigned int* MD5(const char* mStr)
{
	unsigned int mLen = strlen(mStr); //计算字符串长度
	if (mLen < 0) return 0;
	unsigned int FillSize = 448 - ((mLen * 8) % 512); //计算需填充的bit数
	unsigned int FSbyte = FillSize / 8; //以字节表示的填充数
	unsigned int BuffLen = mLen + 8 + FSbyte; //缓冲区长度或者说填充后的长度
	unsigned char *md5Buff = new unsigned char[BuffLen]; //分配缓冲区
	CopyMemory(md5Buff, mStr, mLen); //复制字符串到缓冲区

	/*数据填充开始*/
	md5Buff[mLen] = 0x80; //第一个bit填充1
	ZeroMemory(&md5Buff[mLen + 1], FSbyte - 1); //其它bit填充0，另一可用函数为FillMemory
	unsigned long long lenBit = mLen * 8ULL; //计算字符串长度，准备填充
	CopyMemory(&md5Buff[mLen + FSbyte], &lenBit, 8); //填充长度
	/*数据填充结束*/

	/*运算开始*/
	unsigned int LoopNumber = BuffLen / 64; //以16个字为一分组，计算分组数量
	unsigned int A = 0x67452301, B = 0x0EFCDAB89, C = 0x98BADCFE, D = 0x10325476;//初始4个种子，小端类型
	unsigned int *lGroup = new unsigned int[4];
		lGroup[0]= A;
		lGroup[1]= D;
		lGroup[2]= C;
		lGroup[3]= B;
	   //{ A, D, C, B}; //种子副本数组,并作为返回值返回
	for (unsigned int Bcount = 0; Bcount < LoopNumber; ++Bcount) //分组大循环开始
	{
		/*进入4次计算的小循环*/
		for (unsigned short Lcount = 0; Lcount < 4;)
		{
			AccLoop(++Lcount, lGroup, &md5Buff[Bcount * 64]);
		}
		/*数据相加作为下一轮的种子或者最终输出*/
		A = (lGroup[0] += A);
		B = (lGroup[3] += B);
		C = (lGroup[2] += C);
		D = (lGroup[1] += D);
	}
	/*转换内存中的布局后才能正常显示*/
	ltob(lGroup[0]);
	ltob(lGroup[1]);
	ltob(lGroup[2]);
	ltob(lGroup[3]);
	delete[] md5Buff; //清除内存并返回
	

	return lGroup;
}

main.cpp

#include <iostream>
#include <string.h>
#include <stdlib.h>
#include "MD5.h"

int main(int argc, char **argv)
{
	char tmpstr[256], buf[4][10];
	std::cout << "请输入要加密的字符串：";
	std::cin >> tmpstr;
	unsigned int* tmpGroup = MD5(tmpstr);
	sprintf_s(buf[0], "%8X", tmpGroup[0]);
	sprintf_s(buf[1], "%8X", tmpGroup[3]);
	sprintf_s(buf[2], "%8X", tmpGroup[2]);
	sprintf_s(buf[3], "%8X", tmpGroup[1]);
	std::cout <<"MD5:"<< buf[0] << buf[1] << buf[2] << buf[3] << std::endl;

	delete[] tmpGroup;

	while(1)
	{

	}
	return 0; //在此下断点才能看到输出的值
}