混沌密码加密bmp图像.cpp

使用迭代方程Xn+1=Asin2(Xn-XB)生成混沌序列{Xi}

// 混沌密码加密BMP图像.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include "math.h"
#include<iostream>
using namespace std;

double A;
double Xb;
double Xn;

//生成混沌序列x[8]
void product_x(double *x,double x0)
{
	int i;
	x[0]=A*sin(x0-Xb)*sin(x0-Xb);
	for(i=0;i<7;i++)
		x[i+1]=A*sin(x[i]-Xb)*sin(x[i]-Xb);
}

//生成8bit的K值
void product_k(unsigned char *K,double *x)
{
	int i;
	for(i=0;i<8;i++)
	{
		if(x[i]>=(2*A/3))
			(*K)=((*K)<<1)+1;
		else (*K)=(*K)<<1;
	}
}

//加密-解密
void encryption(FILE *bmp1,FILE *bmp2)
{
	unsigned char temp,tmp;
	double X[8],x0;
	unsigned char K;
	int i;
	for(i=0;i<118;i++)
	{
		tmp=fgetc(bmp1);
		fputc(tmp,bmp2);
	}
	X[7]=Xn;
	while(!feof(bmp1))
	{
		temp=fgetc(bmp1);
		x0=X[7];
		product_x(X,x0);
		product_k(&K,X);
		temp=temp^K;
		fputc(temp,bmp2);
	}

}

int _tmain(int argc, _TCHAR* argv[])
{
	FILE *bmp,*file;
	char bmp_name[30],filename[30];
	char Q;
	Xn=3.1415926;
str:cout<<"**********混沌密码**********"<<endl;
	cout<<endl<<"加密（E）、解密（D）or退出（O）：";
	cin>>Q;
	if(Q=='E'||Q=='e')
	{
str1:	cout<<"*****使用混沌密码加密BMP图像*****"<<endl<<endl;
	    cout<<"输入BMP文件名：";
	    cin>>filename;
	    cout<<endl<<"输入加密后输出的BMP文件名：";
	    cin>>bmp_name;
	    bmp=fopen(bmp_name,"wb");
	    file=fopen(filename,"rb");
	    if(!file||!bmp)
		{
			cout<<endl<<"打开.bmp文件失败！"<<endl;
		    goto str1;
		}
	    cout<<endl<<"请输入A值：";
    	cin>>A;
	    cout<<endl<<"请输入Xb值：";
	    cin>>Xb;
	    cout<<endl<<endl<<"开始加密！"<<endl<<endl<<"bmp图像加密中……"<<endl;
	    encryption(file,bmp);
	    cout<<endl<<endl<<"图像加密完毕！"<<endl;
		fclose(bmp);
		fclose(file);
		goto str;
	}
	else if(Q=='D'||Q=='d')
	{
str2:	cout<<"*****使用混沌密码解密BMP图像*****"<<endl<<endl;
	    cout<<"输入BMP文件名：";
	    cin>>filename;
	    cout<<endl<<"输入解密密后输出的BMP文件名：";
	    cin>>bmp_name;
	    bmp=fopen(bmp_name,"wb");
	    file=fopen(filename,"rb");
	    if(!file||!bmp)
		{
			cout<<endl<<"打开.bmp文件失败！"<<endl;
		    goto str2;
		}
	    cout<<endl<<"请输入A值：";
    	cin>>A;
	    cout<<endl<<"请输入Xb值：";
	    cin>>Xb;
	    cout<<endl<<endl<<"开始解密！"<<endl<<endl<<"bmp图像解密中……"<<endl;
	    encryption(file,bmp);
	    cout<<endl<<endl<<"图像解密完毕！"<<endl;
		fclose(bmp);
		fclose(file);
		goto str;
	}
	return 0;
}