RC4图像加密/解密

Question

我正在尝试执行图像加密/解密过程。代码正在运行，没有任何错误，但输出不正确。 我无法确定我要去哪里。 相同的代码用于加密和解密。 唯一的区别是更改路径作为输入。 PS：我是Java和图像处理概念的新手。

package crptography;
import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.DataInputStream;
import java.io.File;
import java.io.IOException;
import javax.imageio.IIOImage;
import javax.imageio.ImageIO;
import javax.imageio.ImageWriteParam;
import javax.imageio.ImageWriter;
import javax.imageio.plugins.jpeg.JPEGImageWriteParam;
import javax.imageio.stream.ImageOutputStream;


public class RC4Final {

public static int s[]=new int[256];
public static int t;

public static void main(String args[])throws IOException
{
int i=0,j=0,temp=0;
String key;
int k[]=new int[256];

String path  = "C:\\rc4\\Koala.jpg";
//String path  = "C:\\rc4\\encrypted.jpg";

BufferedImage old_img = null;   

try { old_img = ImageIO.read(new File(path));} 
catch (Exception e) {  e.printStackTrace(); }  



BufferedImage new_img = new BufferedImage( old_img.getWidth(),
                      old_img.getHeight(), 
                      BufferedImage.TYPE_INT_RGB);

int n = new_img.getWidth();
int m = new_img.getHeight();
//initialization array s

DataInputStream in=new DataInputStream(System.in);
System.out.print("\n\nENTER KEY TEXT\t\t");
    key = in.readLine();
char keyc[]=key.toCharArray();
int keyi[]=new int[key.length()];
for(int a=0;a<key.length();a++)
{
 keyi[a]=(int)keyc[a];
}

for( i=0;i<255;i++)
{
  s[i]=i;
  k[i]=keyi[i%key.length()];
}
//end

//initial permutation of array s
j=0;
for( i=0;i<255;i++)
{

     j = (j+s[i]+k[i])%256;
     temp = s[i];
     s[i]=s[j];
     s[j]=temp;
}
//end

//encryption start
i=0;
j=0;
int t1;


int red,green,blue,cr,cg,cb;
int rgb ;
for ( i = 0; i < n; ++i) 
  {
     for ( j = 0; j < m; ++j)
     {

            rgb = old_img.getRGB(i,j);
            blue = (rgb)&0xFF;
            green = (rgb>>8)&0xFF;
            red = (rgb>>16)&0xFF;

           t1= permutate(i,j);
           cr=s[t1]^red;
           t1= permutate(i,j);
           cg=s[t1]^green;
           t1=permutate(i,j);
           cb=s[t1]^blue;
           int rgb1=new Color(cr, cg, cb).getRGB();
          new_img.setRGB(i, j, rgb1);
     }

   }

saveToFile( new_img, new File( "C:\\rc4\\encrypted.jpg" ) );
//saveToFile( new_img, new File( "C:\\rc4\\decrypted.jpg" ) );
}
//permute method
public static int permutate(int x,int y)
{
 int temp;
 x=(x+1)%256;
 y=(y+s[x])%256;
 temp = s[x];
 s[x]=s[y];
 s[y]=temp;
 t = s[(s[x]+s[y])%256];
 return t;
}
//end
public static void saveToFile( BufferedImage img, File file ) throws IOException {

    ImageWriter writer = null;

    java.util.Iterator iter = ImageIO.getImageWritersByFormatName("jpg");

    if( iter.hasNext() ){

        writer = (ImageWriter)iter.next();

    }

    ImageOutputStream ios = ImageIO.createImageOutputStream( file );

    writer.setOutput(ios);

    ImageWriteParam param = new JPEGImageWriteParam( java.util.Locale.getDefault() );

    param.setCompressionMode(ImageWriteParam.MODE_EXPLICIT) ;

    param.setCompressionQuality(0.98f);

    writer.write(null, new IIOImage( img, null, null ), param);

    }     
 }