encrypt/decrypt Java

[AMIOX?]

 

encrypt:

 

KeyGenerator keyGenerator = KeyGenerator.getInstance("TripleDES");
            keyGenerator.init(168);
            SecretKey key = keyGenerator.generateKey();
            
            System.out.println("Done generating the key.");
// Create a cipher using that key to initialize it
            Cipher cipher = Cipher.getInstance("TripleDES/ECB/PKCS5Padding");
            cipher.init(Cipher.ENCRYPT_MODE, key);
            
            byte[] plaintextBytes = msg.getBytes();
            
            // Perform the actual encryption
            byte[] cipherText = cipher.doFinal(plaintextBytes);
            
            // Now we need to Base64-encode it for ascii display
            BASE64Encoder encoder = new BASE64Encoder();
            String output = encoder.encode(cipherText);
            
            System.out.println("Ciphertext: "+output);
            
            /* Create a keystore and place the key in it
            * We're using a jceks keystore, which is provided by Sun's JCE.
            * If you don't have the JCE installed, you can use "JKS",
            * which is the default keystore. It doesn't provide
            * the same level of protection however.
            */
            KeyStore keyStore = KeyStore.getInstance("JCEKS");
            
            // This initializes a blank keystore
            keyStore.load(null, null);
            
            // Now we add the key to the keystore, protected
            // by the password.
            keyStore.setKeyEntry("exampleKey", key, pass.toCharArray(), null);
            
            // Store the password to the filesystem, protected
            // by the same password.
            FileOutputStream fos = new FileOutputStream(FILENAME);
            keyStore.store(fos, pass.toCharArray());
            fos.close();

 

 

decrypt:

  KeyStore keyStore = KeyStore.getInstance("JCEKS");
    FileInputStream fis = new FileInputStream(FILENAME);
    keyStore.load(fis, pass.toCharArray());
    fis.close();
    SecretKey key = (SecretKey)keyStore.getKey("exampleKey",pass.toCharArray());


    // Create a cipher using that key to initialize it
    Cipher cipher = Cipher.getInstance("TripleDES/ECB/PKCS5Padding");
    
    cipher.init(Cipher.DECRYPT_MODE, key);


    // Perform the decryption, first BASE64 decoding the ciphertext
    byte[] ciphertextBytes = new BASE64Decoder().decodeBuffer(from);
    byte[] decryptedText = cipher.doFinal(ciphertextBytes);


    String output = new String(decryptedText);


    System.out.println("Plaintext: "+output);

 

 

σφάλμα:

Απρ 18, 2014 5:46:16 ΜΜ chatserver.server5 run
SEVERE: null
javax.crypto.IllegalBlockSizeException: Input length must be multiple of 8 when decrypting with padded cipher
at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:750)
at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:676)
at com.sun.crypto.provider.DESedeCipher.engineDoFinal(DESedeCipher.java:294)
at javax.crypto.Cipher.doFinal(Cipher.java:2087)

Στην εντολή "byte[] decryptedText = cipher.doFinal(ciphertextBytes);" έχει το παραπάνω σφάλμα. Ξέρει κανείς πως το μέγεθος του input θα το κάνω πολλαπλάσιο του 8?

[nilosgr]

Πανω-πανω βαλε:

for (int i = msg.length() % 8; i > 0; --i)
{
  msg = msg + " ";
}