md5.h

C++开发的MD5加密算法

#include <iostream>
#include <string>
#include <stdio.h>
using namespace std;

//每次操作中用到的四个非线性函数F,G,H,I
unsigned int F(unsigned int x, unsigned int y, unsigned int z)
{
	return (x & y) | ((~x) & z);
}

unsigned int G(unsigned int x, unsigned int y, unsigned int z)
{
	return (x & z) | (y & (~z));
}

unsigned int H(unsigned int x, unsigned int y, unsigned int z)
{
	return x ^ y ^ z;
}

unsigned int I(unsigned int x, unsigned int y, unsigned int z)
{
	return y^(x|(~z));
}

//循环左移
unsigned int RotateLeft(unsigned int x, unsigned int s)
{
	unsigned int a, b;
	a=x<<s;
	b=x>>(32-s);
	return a|b;
}

//t应该为t[i],其中1<=i<=64,t[i]=4294967296*abs(sin(i))的整数部分，i的单位是弧度(4294967296等于2的32次方)
void FF(unsigned int &a, unsigned int &b, unsigned int &c, unsigned int &d, unsigned int &m, unsigned int s, unsigned int t)
{
	a=b+RotateLeft((a+F(b, c, d)+m+t), s);
}

void GG(unsigned int &a, unsigned int &b, unsigned int &c, unsigned int &d, unsigned int &m, unsigned int s, unsigned int t)
{
	a=b+RotateLeft((a+G(b, c, d)+m+t), s);
}

void HH(unsigned int &a, unsigned int &b, unsigned int &c, unsigned int &d, unsigned int &m, unsigned int s, unsigned int t)
{
	a=b+RotateLeft((a+H(b, c, d)+m+t), s);
}

void II(unsigned int &a, unsigned int &b, unsigned int &c, unsigned int &d, unsigned int &m, unsigned int s, unsigned int t)
{
	a=b+RotateLeft((a+I(b, c, d)+m+t), s);
}

//定义算法的四轮循环运算
void Recurrence(unsigned int &a, unsigned int &b, unsigned int &c, unsigned int &d, unsigned int *M)
{
	//第一轮
	FF(a,b,c,d,M[0],7,0xd76aa478);
	FF(d,a,b,c,M[1],12,0xe8c7b756);
	FF(c,d,a,b,M[2],17,0x242070db);
	FF(b,c,d,a,M[3],22,0xc1bdceee);
	FF(a,b,c,d,M[4],7,0xf57c0faf);
	FF(d,a,b,c,M[5],12,0x4787c62a);
	FF(c,d,a,b,M[6],17,0xa8304613);
	FF(b,c,d,a,M[7],22,0xfd469501);
	FF(a,b,c,d,M[8],7,0x698098d8);
	FF(d,a,b,c,M[9],12,0x8b44f7af);
	FF(c,d,a,b,M[10],17,0xffff5bb1);
	FF(b,c,d,a,M[11],22,0x895cd7be);
	FF(a,b,c,d,M[12],7,0x6b901122);
	FF(d,a,b,c,M[13],12,0xfd987193);
	FF(c,d,a,b,M[14],17,0xa679438e);
	FF(b,c,d,a,M[15],22,0x49b40821); 

	//第二轮
	GG(a,b,c,d,M[1],5,0xf61e2562);
	GG(d,a,b,c,M[6],9,0xc040b340);
	GG(c,d,a,b,M[11],14,0x265e5a51);
	GG(b,c,d,a,M[0],20,0xe9b6c7aa);
	GG(a,b,c,d,M[5],5,0xd62f105d);
	GG(d,a,b,c,M[10],9,0x02441453);
	GG(c,d,a,b,M[15],14,0xd8a1e681);
	GG(b,c,d,a,M[4],20,0xe7d3fbc8);
	GG(a,b,c,d,M[9],5,0x21e1cde6);
	GG(d,a,b,c,M[14],9,0xc33707d6);
	GG(c,d,a,b,M[3],14,0xf4d50d87);
	GG(b,c,d,a,M[8],20,0x455a14ed);
	GG(a,b,c,d,M[13],5,0xa9e3e905);
	GG(d,a,b,c,M[2],9,0xfcefa3f8);
	GG(c,d,a,b,M[7],14,0x676f02d9);
	GG(b,c,d,a,M[12],20,0x8d2a4c8a);

	//第三轮
	HH(a,b,c,d,M[5],4,0xfffa3942);
	HH(d,a,b,c,M[8],11,0x8771f681);
	HH(c,d,a,b,M[11],16,0x6d9d6122);
	HH(b,c,d,a,M[14],23,0xfde5380c);
	HH(a,b,c,d,M[1],4,0xa4beea44);
	HH(d,a,b,c,M[4],11,0x4bdecfa9);
	HH(c,d,a,b,M[7],16,0xf6bb4b60);
	HH(b,c,d,a,M[10],23,0xbebfbc70);
	HH(a,b,c,d,M[13],4,0x289b7ec6);
	HH(d,a,b,c,M[0],11,0xeaa127fa);
	HH(c,d,a,b,M[3],16,0xd4ef3085);
	HH(b,c,d,a,M[6],23,0x04881d05);
	HH(a,b,c,d,M[9],4,0xd9d4d039);
	HH(d,a,b,c,M[12],11,0xe6db99e5);
	HH(c,d,a,b,M[15],16,0x1fa27cf8);
	HH(b,c,d,a,M[2],23,0xc4ac5665);

	//第四轮
	II(a,b,c,d,M[0],6,0xf4292244);
	II(d,a,b,c,M[7],10,0x432aff97);
	II(c,d,a,b,M[14],15,0xab9423a7);
	II(b,c,d,a,M[5],21,0xfc93a039);
	II(a,b,c,d,M[12],6,0x655b59c3);
	II(d,a,b,c,M[3],10,0x8f0ccc92);
	II(c,d,a,b,M[10],15,0xffeff47d);
	II(b,c,d,a,M[1],21,0x85845dd1);
	II(a,b,c,d,M[8],6,0x6fa87e4f);
	II(d,a,b,c,M[15],10,0xfe2ce6e0);
	II(c,d,a,b,M[6],15,0xa3014314);
	II(b,c,d,a,M[13],21,0x4e0811a1);
	II(a,b,c,d,M[4],6,0xf7537e82);
	II(d,a,b,c,M[11],10,0xbd3af235);
	II(c,d,a,b,M[2],15,0x2ad7d2bb);
	II(b,c,d,a,M[9],21,0xeb86d391);
}

//这个MD5算法实现的主函数
void Realize(string str)
{	
	unsigned int M[16];
	unsigned short *T;

	//定义链接变量
	unsigned int A = 0x67452301;
	unsigned int B = 0xefcdab89;
	unsigned int C = 0x98badcfe;
	unsigned int D = 0x10325476;

	unsigned int AA;
	unsigned int BB;
	unsigned int CC;
	unsigned int DD;

	unsigned int N;
	unsigned int length=str.length();
	unsigned long hexLen;

	int n;
    int ones = 1;
    int m = length % 64;
    
	if (m == 56)
    {
       ones = 0;
    }

	if(m<56)
	{
		N=length/64+1;
	}
	else
	{
		N=length/64+2;
	}

	T=new unsigned short[N*64];
	for(n=0; n<N*64; n++)
	{
		T[n]=0;
	}

	for(n=0; n<length; n++)
	{
		T[n]=(unsigned short)str.at(n);
	}

	if(ones==1)
	{
		T[n]=0x80;

		for(n=length+1; n<N*64-8; n++)
		{
			T[n]=0x00;
		}
	}

	hexLen=length*8;
	for(; n<N*64; n++)
	{
		if(n<60)
		{
			T[n]=(unsigned short)hexLen&0xff;
			hexLen=hexLen>>8;
		}
		else
		{
			T[n]=(unsigned short)hexLen&0xff;
			hexLen=hexLen>>8;
		}
	}

	for(int i=0; i<N; i++)
	{
		for(int j=0; j<16; j++)
		{
			M[j]=((int)T[i*64+j*4]|(int)(T[i*64+j*4+1]<<8)|(int)(T[i*64+j*4+2]<<16)|(int)(T[i*64+j*4+3]<<24));
		}

		//将上面四个链接变量A,B,C,D复制到另外四个变量AA,BB,CC,DD中
		AA=A;
		BB=B;
		CC=C;
		DD=D;

		//进入四轮循环运算
		Recurrence(A, B, C, D, M);

		//将A,B,C,D加上AA,BB,CC,DD，继续参与到下一次的运算中
		A=A+AA;
		B=B+BB;
		C=C+CC;
		D=D+DD;
	}

	//将最后得到的A,B,C,D按顺序以十六进制表示方法输出
	unsigned short output[16];
	unsigned int bits[]={A, B, C, D};
	int j;
	for (i = 0, j = 0; i < 16; i++, j += 4)
    {
       output[j] = (unsigned short)(bits[i] & 0xff);
       output[j + 1] = (unsigned short)((bits[i] >> 8) & 0xff);
       output[j + 2] = (unsigned short)((bits[i] >> 16) & 0xff);
       output[j + 3] = (unsigned short)((bits[i] >> 24) & 0xff);
    }

	for(i=0; i<16; i++)
	{
		//将output[i]以十六进制形式输出
		printf("%02x", output[i]);
	}
	cout<<endl;
}