javax.crypto.IllegalBlockSizeException: When Decoding an Input String

[Tom Walsh]

Hello, I have been given the following class for encrypting and decrypting password strings. I can encrypt ok but I receive errors when I try to decrypt. The error is as follows

EncryptionHelper.encrypt...byte array length: 18EncryptionHelper.encrypt...string interpretation: [B@b179c3 Encrypt len = 44 EncryptionHelper.encrypt...return value: [B@67ac19 String decoded = [B@53ba3d Lent=5 testt Controller.main...exception, illegal block size: javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher
javax.crypto.IllegalBlockSizeException: Input length must be multiple of 16 when decrypting with padded cipher
at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
at com.sun.crypto.provider.SunJCE_f.b(DashoA13*..)
at com.sun.crypto.provider.AESCipher.engineDoFinal(DashoA13*..)
at javax.crypto.Cipher.doFinal(DashoA13*..)
at com.avaya.utility.updater.EncryptionHelper.decrypt(EncryptionHelper.java:60)
at com.avaya.utility.updater.Controller.main(Controller.java:90)

My class is as follows

package com.avaya.utility.updater;

import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;
import org.apache.commons.codec.binary.*;

public class EncryptionHelper {
	private String algorithm = "AES";
	private SecretKeySpec  keySpec = null;
	private byte[] key = "tan!#12mayW0T!==".getBytes();

	private Cipher cipher = null;
	
	public EncryptionHelper() throws NoSuchAlgorithmException, NoSuchPaddingException{	
		cipher = Cipher.getInstance(algorithm);
		keySpec = new SecretKeySpec(key, algorithm);
	}

	public String encrypt(String input) throws InvalidKeyException, BadPaddingException,IllegalBlockSizeException {		
		
		cipher.init(Cipher.ENCRYPT_MODE, keySpec);
		
		byte[] inputBytes = input.getBytes();
		System.out.print("EncryptionHelper.encrypt...byte array length: " + inputBytes.length);
		
		String returnVal = inputBytes.toString();		
		System.out.print("EncryptionHelper.encrypt...string interpretation: " + returnVal);
		
		//return new sun.misc.BASE64Encoder().encode(cipher.doFinal(inputBytes));
		
		byte[] finalResult = input.getBytes();		
		finalResult =org.apache.commons.codec.binary.Base64.encodeBase64(cipher.doFinal(inputBytes));
		
		System.out.print(" Encrypt len = " + finalResult.length + " ");		
				
		String encryptedStr = finalResult.toString();
		System.out.print("EncryptionHelper.encrypt...return value: " + encryptedStr);
		
		return encryptedStr;
		
		//return new org.apache.commons.codec.binary.encodeBase64(cipher.doFinal(inputBytes));		
	}

	
	public String decrypt(String passphrase) throws InvalidKeyException,BadPaddingException, IllegalBlockSizeException, IOException {
			
		byte[] passPhraseBytes = passphrase.getBytes();			
	        byte[] encryptionBytes = org.apache.commons.codec.binary.Base64.decodeBase64(passPhraseBytes);
		System.out.print(" String decoded = " + encryptionBytes.toString() + " ");			    
		System.out.print("Lent=" + encryptionBytes.length + " ");
		cipher.init(Cipher.DECRYPT_MODE, keySpec);
		System.out.print(" testt  ");		
		byte[] recoveredBytes = cipher.doFinal(encryptionBytes);
		System.out.print(" testt 2 ");			
		String recovered = new String(recoveredBytes);

		System.out.print("EncryptionHelper.decrypt...return value: " + recovered);

		return recovered;
	}
}

The error occurs at the following line "byte[] recoveredBytes = cipher.doFinal(encryptionBytes);"

How can I confirm that "byte[] encryptionBytes" will be a multiple of 16?

Thanks!