private static String bytetoString(byte[] digest) {
        String str = "";
        String tempStr = "";
        
        for (int i = 0; i < digest.length; i++) {
            tempStr = (Integer.toHexString(digest[i] & 0xff));
            if (tempStr.length() == 1) {
                str = str + "0" + tempStr;
            }
            else {
                str = str + tempStr;
            }
        }
        return str.toLowerCase();
    }