protected static KeyPair signWithRsa() {
        KeyPair keyPair = null;
        try {
            KeyPairGenerator kpGenerator = KeyPairGenerator.getInstance("RSA");
            kpGenerator.initialize(4096);
            java.security.KeyPair keypair = kpGenerator.generateKeyPair();
            PublicKey publicKey = keypair.getPublic();
            PrivateKey privateKey = keypair.getPrivate();
            ContentSigner signer = new JcaContentSignerBuilder("SHA256WithRSA").build(keypair.getPrivate());
            keyPair = new KeyPair(publicKey, privateKey, signer);
        } catch (NoSuchAlgorithmException | OperatorCreationException e) {
            logger.error(
                    CONFIG_SSL_CERT_GENERATE_FAILED,
                    "",
                    "",
                    "Generate Key with SHA256WithRSA algorithm failed. Please check if your system support.",
                    e);
        }
        return keyPair;
    }
@Test
    void testSignWithRsa() {
        DubboCertManager.KeyPair keyPair = DubboCertManager.signWithRsa();
        Assertions.assertNotNull(keyPair);
        Assertions.assertNotNull(keyPair.getPrivateKey());
        Assertions.assertNotNull(keyPair.getPublicKey());
        Assertions.assertNotNull(keyPair.getSigner());
    }