Decryption error on Android 4.4

Question

I have algorithm of encryption\ decryption files:

    private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
    Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
    cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
    byte[] encrypted = cipher.doFinal(clear);
    return encrypted;
}


private static byte[] getRawKey(byte[] seed) throws Exception {
    KeyGenerator kgen = KeyGenerator.getInstance("AES");
    SecureRandom sr = new SecureRandom();
    sr.setSeed(seed);
    kgen.init(sr); // 192 and 256 bits may not be available
    SecretKey skey = kgen.generateKey();
    byte[] raw = skey.getEncoded();
    return raw;
}

private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
    SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
    Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
    cipher.init(Cipher.DECRYPT_MODE, skeySpec);
    byte[] decrypted = cipher.doFinal(encrypted);
    return decrypted;

}

It works great, but on Android 4.4 (api 19) I have strangely exception

javax.crypto.BadPaddingException: error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt

What is it?

Answer 1

Here what I got: http://www.logikdev.com/2010/11/01/encrypt-with-php-decrypt-with-java/

   public class AES2 {

    private static final String TRANSFORMATION = "AES/CFB8/NoPadding";
    private static final String ALGO_MD5       = "MD5";
    private static final String ALGO_AES       = "AES";

    /**
     * See http://www.logikdev.com/2012/12/12/md5-generates-31-bytes-instead-of-32/ form more detail.
     * 
     * @param input
     * @return
     * @throws NoSuchAlgorithmException
     */
    private static String md5(String input) throws NoSuchAlgorithmException {
        MessageDigest md = MessageDigest.getInstance(ALGO_MD5);
        byte[] messageDigest = md.digest(input.getBytes());
        BigInteger number = new BigInteger(1, messageDigest);
        return String.format("%032x", number);
    }

    public static String decrypt(String encryptedData, String initialVectorString, String secretKey) {
        String decryptedData = null;
        try {
            String md5Key = md5(secretKey);
            SecretKeySpec skeySpec = new SecretKeySpec(md5Key.getBytes(), ALGO_AES);
            IvParameterSpec initialVector = new IvParameterSpec(initialVectorString.getBytes());
            Cipher cipher = Cipher.getInstance(TRANSFORMATION);
            cipher.init(Cipher.DECRYPT_MODE, skeySpec, initialVector);
            byte[] encryptedByteArray = Base64.decode(encryptedData.getBytes(), Base64.DEFAULT);
            byte[] decryptedByteArray = cipher.doFinal(encryptedByteArray);
            decryptedData = new String(decryptedByteArray);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (InvalidAlgorithmParameterException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }

        return decryptedData;
    }

}

So you have to create a initialVectorString (example: "fedcba9876543210"). Hope this help.