将加密的图像字节保存到文件并在Java中恢复为原始图像

Question

i have a problem with encryption and decryption of an image the reason is identified now but I couldn't figureout the solution.

and I am trying to implement this project

but the problem is encrypted image bytes are not recovered after written to an image file using rasterclass and ImageIO class

my problem,tried code and explanations are submitted here

I have to embed text in an encrypted image(Stegnography). I googled and found codes for embedding text in an image. But I have to encrypt image at first and embed text in this encrypted image. My tries are as follows.

/*
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 * and open the template in the editor.
 */
package tbn;

import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.Transparency;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.ComponentColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferByte;
import java.awt.image.Raster;
import java.awt.image.WritableRaster;
import java.io.File;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.imageio.ImageIO;

/**
 *
 * @author user
 */
public class DbtClass {

    public static void main(String[] args) {
        try {
            BufferedImage orgnlimage = ImageIO.read(new File("parrruuuuu.png"));
            orgnlimage = user_space(orgnlimage);
            byte[] orgnlimagebytes = get_byte_data(orgnlimage);
            byte[] encryptedbytes = encrypt(orgnlimagebytes, "abc");
            BufferedImage encryptedimage = toImage(encryptedbytes, orgnlimage.getWidth(), orgnlimage.getHeight());
            ImageIO.write(encryptedimage, "png", new File("encrypted.png"));

            /////////////////////////////////////////////////////////////////////
            /////////////////////////////////////////////////////////////////////

            byte[] encryptedbytes2 = get_byte_data(encryptedimage);
            System.out.println("encryptedbytes before writing: "+encryptedbytes2.length);

            BufferedImage encryptedimage3 = ImageIO.read(new File("encrypted.png"));
            byte[] encryptedbyte3 = get_byte_data(encryptedimage3);
            System.out.println("encryptedbytes after writing: "+encryptedbyte3.length);


        } catch (IOException ex) {
            Logger.getLogger(DbtClass.class.getName()).log(Level.SEVERE, null, ex);
        }
    }

    public static BufferedImage user_space(BufferedImage image) {
        //create new_img with the attributes of image
        BufferedImage new_img = new BufferedImage(image.getWidth(), image.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
        Graphics2D graphics = new_img.createGraphics();
        graphics.drawRenderedImage(image, null);
        graphics.dispose(); //release all allocated memory for this image
        return new_img;
    }

    public static byte[] get_byte_data(BufferedImage image) {
        WritableRaster raster = image.getRaster();
        DataBufferByte buffer = (DataBufferByte) raster.getDataBuffer();
        return buffer.getData();
    }

    public static byte[] encrypt(byte[] orgnlbytes, String key) {
        byte[] encbytes = null;
        try {
            Cipher cipher = Cipher.getInstance("AES");
            KeyGenerator keyGen = KeyGenerator.getInstance("AES");
            SecureRandom random = SecureRandom.getInstance("SHA1PRNG");
            // cryptograph. secure random 
            random.setSeed(key.getBytes());

            keyGen.init(128, random);
            // for example
            SecretKey secretKey = keyGen.generateKey();
            cipher.init(Cipher.ENCRYPT_MODE, secretKey);
            encbytes = cipher.doFinal(orgnlbytes);
        } catch (NoSuchAlgorithmException ex) {
            Logger.getLogger(DbtClass.class.getName()).log(Level.SEVERE, null, ex);
        } catch (NoSuchPaddingException ex) {
            Logger.getLogger(DbtClass.class.getName()).log(Level.SEVERE, null, ex);
        } catch (InvalidKeyException ex) {
            Logger.getLogger(DbtClass.class.getName()).log(Level.SEVERE, null, ex);
        } catch (IllegalBlockSizeException ex) {
            Logger.getLogger(DbtClass.class.getName()).log(Level.SEVERE, null, ex);
        } catch (BadPaddingException ex) {
            Logger.getLogger(DbtClass.class.getName()).log(Level.SEVERE, null, ex);
        }
        return encbytes;
    }

    public static BufferedImage toImage(byte[] imagebytes, int width, int height) {
        DataBuffer buffer = new DataBufferByte(imagebytes, imagebytes.length);
        WritableRaster raster = Raster.createInterleavedRaster(buffer, width, height, 3 * width, 3, new int[]{2, 1, 0}, (Point) null);
        ColorModel cm = new ComponentColorModel(ColorModel.getRGBdefault().getColorSpace(), false, true, Transparency.OPAQUE, DataBuffer.TYPE_BYTE);
        return new BufferedImage(cm, raster, true, null);
    }
}

Here I was written the encrypted image using raster class and ImageIO.write().Then read this encrypted bytes from file Using ImageIO.read().The encrypted byte[] before writing the image and the byte[] after reading the image are totaly different

I got reason for this here but I don't know what to do here to overcome

Answer 1

I got a solution by replacing AES encryption by XOR encryption this will never cause the data loss by writing encrypted image bytes to image file

so thank you for your responses in every time in thids and previuos question