md5.cpp

MD5简单版的杂凑函数；使用C++语言编写

#include<iostream.h>
#include<string.h>
#include<stdio.h>
const int LeftMove[64]=   //压缩函数每步左循环移位的位数
{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 int order[64] = 
{
	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
};

const unsigned long T[64]=
{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
};
class MD5
{
private:
	char *mess;//明文字符串
	int length;//明文长度
	unsigned long *M;//消息分组为32比特的字
	int L;//消息填充以后消息的分组数目
	int N;//消息中32比特长的字的总数，N=L*16
	unsigned long MD_A;
	unsigned long MD_B;
	unsigned long MD_C;
	unsigned long MD_D;
public:
	MD5()
	{
		MD_A=0x67452301;//MD缓冲区初始化
		MD_B=0xEFCDAB89;
		MD_C=0x98BADCFE;
		MD_D=0x10325476;
		cout<<"输入明文:"<<endl;
		char str[100];
		cin>>str;
		length=strlen(str);
		cout<<length<<endl;
		mess=new char[length];
		for(int i=0;i<length;i++)
		{
			mess[i]=str[i];
		}
		cout<<mess<<endl;
		fillMess();
		M=new unsigned long[N];
		for(i=0;i<N;i++)
		{
			M[i]=0;
		}
	}
	char input()
	{
		char ch;
		cin>>ch;
		return ch;
	}
	void fillMess()//计算出消息填充以后消息的分组数目
	{
		int tmp;//明文字符串的比特数
		tmp=length*8;
		int tmp0;//tmp模512
		tmp0=tmp%512;
		if(tmp0<448)
		{
			tmp+=(448-tmp0);
		}
		else if(tmp0>448)
		{
			tmp+=(448+512-tmp0);
		}
		else if(tmp0==448)
		{
			tmp+=512;
		}
		
		L=tmp/512+1;
		N=L*16;
		cout<<tmp<<endl;
		cout<<L<<endl;
		cout<<N<<endl;
	}
	void trans(unsigned long& a)
	{
		a=((a&0xff000000)>>24)|
			((a&0x00ff0000)>>8)|
			((a&0x0000ff00)<<8)|
			((a&0x000000ff)<<24);
	}
	void group()
	{
		int n=0;
		
		for(int i=0;i<(length/4)*4;i++)
		{
			n=i/4;
			M[n]=M[n]<<8;
			M[n]=M[n]|((unsigned long)mess[i] & 255);
		}
		
		if(length%4==0)
		{
			if(length>=4)
				n++;
			M[n]=0x80000000UL & 0xffffffffUL;
		}
		else if(length%4!=0)
		{
			if(length>=4)
				n++;
			switch(length-length/4*4)
			{
			case 1:
				M[n]=(((unsigned long)mess[length/4*4] & 255)<<24)|
					(0x80UL<<16);
				break;
			case 2:
				M[n]=(((unsigned long)mess[length/4*4] & 255)<<24) |
					(((unsigned long)mess[length/4*4+1] & 255)<<16)|
					(0x80UL<<8);
				break;
			case 3:
				M[n]=(((unsigned long)mess[length/4*4] & 255)<<24) |
					(((unsigned long)mess[length/4*4+1] & 255)<<16)|
					(((unsigned long)mess[length/4*4+2] & 255)<<8) |
					(0x80UL);
				break;
			default:
				break;
			}
		}
		for(i=0;i<L*N-2;i++)
		{
			trans(M[i]);
		}
		M[N-2]=length*8;//
		//考虑到输入的字符串长度有限，不可能超过2的32次方，故最后一个字为0
		M[N-1]=0;
		/**/
		for(i=0;i<L*N;i++)
		{
			printf(" %x",M[i]);
		}
		cout<<endl;
	}
	
	unsigned long F(unsigned long b,unsigned long c,unsigned long d)
	{
		return (d^(b&(c^d)));
	}
	unsigned long G(unsigned long b,unsigned long c,unsigned long d)
	{
		return (c^(d&(c^b)));
	}
	unsigned long H(unsigned long b,unsigned long c,unsigned long d)
	{
		return (b^c^d);
	}
	unsigned long I(unsigned long b,unsigned long c,unsigned long d)
	{
		return (c^(b|(~d)));
	}
	unsigned long LRotate(unsigned long a,int bits)
	{
		return (a<<bits)|(a>>(32-bits));
	}
	void hash()//
	{
		unsigned long a=0,b=0,c=0,d=0,tmp=0;
		a=MD_A;
		b=MD_B;
		c=MD_C;
		d=MD_D;
		for(int i=0;i<16;i++)//第一轮
		{
			tmp=F(b,c,d);
			tmp=tmp+a+M[order[i]]+T[i];
			tmp=LRotate(tmp,LeftMove[i]);
			a=b+tmp;
			
			tmp=d;
			d=c;
			c=b;
			b=a;
			a=tmp;
		}
		for(;i<32;i++)//第二轮
		{
			tmp=G(b,c,d);
			tmp=tmp+a+M[order[i]]+T[i];
			tmp=LRotate(tmp,LeftMove[i]);
			a=b+tmp;
			
			tmp=d;
			d=c;
			c=b;
			b=a;
			a=tmp;
		}
		for(;i<48;i++)//第三轮
		{
			tmp=H(b,c,d);
			tmp=tmp+a+M[order[i]]+T[i];
			tmp=LRotate(tmp,LeftMove[i]);
			a=b+tmp;

			tmp=d;
			d=c;
			c=b;
			b=a;
			a=tmp;
		}
		cout<<"*********************************************"<<endl;
		for(;i<64;i++)//第四轮
		{
			tmp=I(b,c,d);
			tmp=tmp+a+M[order[i]]+T[i];
			tmp=LRotate(tmp,LeftMove[i]);
			a=b+tmp;
			
			tmp=d;
			d=c;
			c=b;
			b=a;
			a=tmp;
		}
		MD_A+=a;
		MD_B+=b;
		MD_C+=c;
		MD_D+=d;
	}
	void output()
	{
		trans(MD_A);
		trans(MD_B);
		trans(MD_C);
		trans(MD_D);
		printf("%x\n",MD_A);
		printf("%x\n",MD_B);
		printf("%x\n",MD_C);
		printf("%x\n",MD_D);
	}
};
void main()
{
	MD5 md5;
	md5.group();
	md5.hash();
	md5.output();
}