Cryptography - deciphering doesn't yield the same text

[Franc Dijan]

Hi,

I'm trying to implement cyptography and found this code sample from Java SE documentation.
However, when I encrypt a text and then decrypt it again, the end result is not the same as the original text.
Could you tell me what's wrong?

Thanks!

	    KeyGenerator keygen = KeyGenerator.getInstance("DES");
	    SecretKey desKey = keygen.generateKey();	    
	    
	    Cipher desCipher;

	    // Create the cipher 
	    desCipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
	    
	    // Initialize the cipher for encryption
	    desCipher.init(Cipher.ENCRYPT_MODE, desKey);

	    // Our cleartext
	    byte[] cleartext = "This is just an example".getBytes();
	    System.out.println("cleartext : " + cleartext);
	    
	    // Encrypt the cleartext
	    byte[] ciphertext = desCipher.doFinal(cleartext);
	    System.out.println("ciphertext : " + ciphertext);
	    
	    // Initialize the same cipher for decryption
	    desCipher.init(Cipher.DECRYPT_MODE, desKey);

	    // Decrypt the ciphertext
	    byte[] cleartext1 = desCipher.doFinal(ciphertext);
	    System.out.println("cleartext1 : " + cleartext1);
	    
	    Assert.assertEquals(cleartext, cleartext1);	

Result:
cleartext : [B@dd20f6
ciphertext : [B@723d7c
cleartext1 : [B@22c95b

[Henry Wong]

Franc Dijan wrote:
cleartext : [B@dd20f6
ciphertext : [B@723d7c
cleartext1 : [B@22c95b

You are not printing the values of the clear and cipher text array. You are printing the value returned by the toString() method for the byte array -- which is just "[B", which means byte array, followed by the identity hash code.

Henry

[Rob Spoor]

Also, for arrays .equals returns only if the two references are the same (in other words, ==). Use assertArrayEquals to test if they are the same:

Assert.assertArrayEquals(cleartext, cleartext1);

[Franc Dijan]

You two are absolutely right. I've changed the comparison & print method & the two text were the same all along.
Thanks!

[Rob Spoor]

You're welcome.