public String decrypt(String dec) throws IOException, NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {

        InputStream mybyte = new ByteArrayInputStream(dec.getBytes());

        SecretKeySpec sks = new SecretKeySpec("MyDifficultPassw".getBytes(), "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, sks);
        CipherInputStream cis = new CipherInputStream(mybyte, cipher);
        int b;
        byte[] d = new byte[8];
        String s="";
        while((b = cis.read(d)) != -1) {
            //fos.write(d, 0, b);
            s+=b;
        }

        Toast.makeText(this,s,Toast.LENGTH_LONG).show();

        cis.close();

        return s;
    }