public static void decrypt(InputStream is, OutputStream os) throws IOException, NoSuchPaddingException, NoSuchAlgorithmException, ClassNotFoundException, InvalidAlgorithmParameterException, InvalidKeyException { SecretKey key = Deserializer.deserializeObject(); // get Cipher instance and initiate in decrypt mode Cipher decryptCipher = Cipher.getInstance("AES"); decryptCipher.init(Cipher.DECRYPT_MODE, key); // create CipherOutputStream to decrypt the data using decryptCipher is = new CipherInputStream(is, decryptCipher); writeData(is, os); }