画像ファイルの暗号化と復号化を行いたい。ただし、このコードを実行すると、このエラーが発生します
Exception in thread "main" java.lang.ClassCastException: javax.crypto.CipherInputStream cannot be cast to javax.imageio.stream.ImageOutputStream
at encypt.com.trial.main(trial.java:82)
そして、sheepTest.png画像を開こうとすると、ファイルが破損しているか、破損しているか、大きすぎるため、開くことができません。
私はすでに多くの方法を試しましたが、それでも間違いを見つけることができません。誰かが私にエラーを解決するのを手伝ってもらえますか？ありがとうございました。
public class trial {
public static void main(String[] arg) throws Exception {
// Scanner to read the user's password. The Java cryptography
// architecture points out that strong passwords in strings is a
// bad idea, but we'll let it go for this assignment.
Scanner scanner = new Scanner(System.in);
// Arbitrary salt data, used to make guessing attacks against the
// password more difficult to pull off.
byte[] salt = { (byte) 0xc7, (byte) 0x73, (byte) 0x21, (byte) 0x8c,
(byte) 0x7e, (byte) 0xc8, (byte) 0xee, (byte) 0x99 };
{
File inputFile = new File("sheep.png");
BufferedImage input = ImageIO.read(inputFile);
Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
SecretKeyFactory keyFac = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
// Get a password from the user.
System.out.print("Password: ");
System.out.flush();
PBEKeySpec pbeKeySpec = new PBEKeySpec(scanner.nextLine().toCharArray());
// Set up other parameters to be used by the password-based
// encryption.
PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, 20);
SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
// Make a PBE Cyhper object and initialize it to encrypt using
// the given password.
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
pbeCipher.init(Cipher.ENCRYPT_MODE, pbeKey, pbeParamSpec);
FileOutputStream output = new FileOutputStream("sheepTest.png");
CipherOutputStream cos = new CipherOutputStream(
output, pbeCipher);
//File outputFile = new File("image.png");
ImageIO.write(input,"PNG",cos);
cos.close();
}
// Now, create a Cipher object to decrypt for us. We are repeating
// some of the same code here to illustrate how java applications on
// two different hosts could set up compatible encryption/decryption
// mechanisms.
{
File inputFile = new File("sheepTest.png");
BufferedImage input = ImageIO.read(inputFile);
// Get another (hopefully the same) password from the user.
System.out.print("Decryption Password: ");
System.out.flush();
PBEKeySpec pbeKeySpec = new PBEKeySpec(scanner.next().toCharArray());
// Set up other parameters to be used by the password-based
// encryption.
PBEParameterSpec pbeParamSpec = new PBEParameterSpec(salt, 20);
SecretKeyFactory keyFac = SecretKeyFactory
.getInstance("PBEWithMD5AndDES");
SecretKey pbeKey = keyFac.generateSecret(pbeKeySpec);
// Make a PBE Cyper object and initialize it to decrypt using
// the given password.
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
pbeCipher.init(Cipher.DECRYPT_MODE, pbeKey, pbeParamSpec);
// Decrypt the ciphertext and then print it out.
/*byte[] cleartext = pbeCipher.doFinal(ciphertext);
System.out.println(new String(cleartext));*/
FileInputStream output = new FileInputStream("sheepTest.png");
CipherInputStream cos = new CipherInputStream(
output, pbeCipher);
ImageIO.write(input,"PNG",(ImageOutputStream) cos);
cos.close();
}
}
}