Getting a SSLContext from different sources

Introduction

A SSLContext is used to secure your websocket connection.

Secure a websocket connection

To secure your connection, e.g. to use a websocket-connection on a https site, you have to add the following lines to your WebsocketServer class.

SSLContext sslContext = <method>;
if (sslContext != null) {
	setWebSocketFactory(new DefaultSSLWebSocketServerFactory(sslContext));
}

Please choose from one of the following examples provided.

I (marci4) check for null just because this indicates that there was an error creating an SSLContext.

If you found another way to implement this, feel free to share it with us.

Getting a SSLContext using a keystore

Credits to bendem on github.com for sharing his code.

You can find an example how to generate your keystore here.

Please adjust the variables keystore, storePassword and keyPassword accordingly.

/**
* Method which returns a SSLContext from a keystore or null if an exception occurred
*
* @return a valid SSLContext or null if an error occurred
*/
private SSLContext getSSLConextFromKeystore() {
	// load up the key store
	String storeType = "JKS";
	String keystore = "server.keystore";
	String storePassword = "storePassword";
	String keyPassword = "keyPassword";

	KeyStore ks;
	SSLContext sslContext;
	try {
		ks = KeyStore.getInstance(storeType);
		ks.load(Files.newInputStream(Paths.get("..", keystore)), storePassword.toCharArray());
		KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
		kmf.init(ks, keyPassword.toCharArray());
		TrustManagerFactory tmf = TrustManagerFactory.getInstance("SunX509");
		tmf.init(ks);


		sslContext = SSLContext.getInstance("TLS");
		sslContext.init(kmf.getKeyManagers(), tmf.getTrustManagers(), null);
	} catch (KeyStoreException | IOException | CertificateException | NoSuchAlgorithmException | KeyManagementException | UnrecoverableKeyException e) {
		return null;
	}
	return sslContext;
}

Getting a SSLContext using a Let’s Encrypt certificate

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Credits to Ryan on stackoverflow.com for sharing his code. I (marci4) modified it a bit for my needs!

Please adjust the variables pathTo and keyPassword accordingly.

/**
* Method which returns a SSLContext from a Let's encrypt or null if an exception occurred
*
* @return a valid SSLContext or null if an error occurred
*/
private SSLContext getSSLContextFromLetsEncrypt() {
	SSLContext context;
	String pathTo = "pem";
	String keyPassword = "keyPassword";
	try {
		context = SSLContext.getInstance("TLS");

		byte[] certBytes = parseDERFromPEM(Files.readAllBytes(new File(pathTo + File.separator + "cert.pem").toPath()), "-----BEGIN CERTIFICATE-----", "-----END CERTIFICATE-----");
		byte[] keyBytes = parseDERFromPEM(Files.readAllBytes(new File(pathTo + File.separator + "privkey.pem").toPath()), "-----BEGIN PRIVATE KEY-----", "-----END PRIVATE KEY-----");

		X509Certificate cert = generateCertificateFromDER(certBytes);
		RSAPrivateKey key = generatePrivateKeyFromDER(keyBytes);

		KeyStore keystore = KeyStore.getInstance("JKS");
		keystore.load(null);
		keystore.setCertificateEntry("cert-alias", cert);
		keystore.setKeyEntry("key-alias", key, keyPassword.toCharArray(), new Certificate[]{cert});

		KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509");
		kmf.init(keystore, keyPassword.toCharArray());

		KeyManager[] km = kmf.getKeyManagers();

		context.init(km, null, null);
	} catch (IOException | KeyManagementException | KeyStoreException | InvalidKeySpecException | UnrecoverableKeyException | NoSuchAlgorithmException | CertificateException e) {
		return null;
	}        
	return context;
}

protected static byte[] parseDERFromPEM(byte[] pem, String beginDelimiter, String endDelimiter) {
	String data = new String(pem);
	String[] tokens = data.split(beginDelimiter);
	tokens = tokens[1].split(endDelimiter);
	return DatatypeConverter.parseBase64Binary(tokens[0]);
}

protected static RSAPrivateKey generatePrivateKeyFromDER(byte[] keyBytes) throws InvalidKeySpecException, NoSuchAlgorithmException {
	PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
	KeyFactory factory = KeyFactory.getInstance("RSA");
	return (RSAPrivateKey) factory.generatePrivate(spec);
}

protected static X509Certificate generateCertificateFromDER(byte[] certBytes) throws CertificateException {
	CertificateFactory factory = CertificateFactory.getInstance("X.509");

	return (X509Certificate) factory.generateCertificate(new ByteArrayInputStream(certBytes));
}