/**
 * Sign JWS object with a given private key.
 *
 * @param jws object to be signed
 * @param key key to sign object with
 * @throws JOSEException invalid key provided
 */
public static void signJwt(JWSObject jws, ECPrivateKey key) throws JOSEException {
    jws.sign(new ECDSASigner(key, ECKey.Curve.P_384));
}