class Utils {

    public static String calcFingerprint(String keyHexString) {
        if (TextUtils.isEmpty(keyHexString)
                || keyHexString.matches(".*[^a-fA-F0-9].*")) {
            Log.e(TAG, "Signing key certificate was blank or contained a non-hex-digit!");
            return null;
        }
        return calcFingerprint(Hasher.unhex(keyHexString));
    }

}