Create app with SSLSocket Java

Question

I want to create an app use SSLSocket: client send a String to server and server will uppercase that String and send back to client fo

Answer 1

Check the certificates that you have installed. Make sure they are supporting the cipher suites that you are negotiating.

Answer 2

@corVaroxid's answer is right. But if you want to set configurations programmatically to avoid global settings (like me), you can go like below (Kotlin):

val password = "yourPassword".toCharArray()

val keyStore = KeyStore.getInstance(File("yourKeystorePath.jks"), password)

val trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm())
trustManagerFactory.init(keyStore)

val keyManagerFactory = KeyManagerFactory.getInstance("NewSunX509")
keyManagerFactory.init(keyStore, password)

val context = SSLContext.getInstance("TLS") //"SSL" "TLS"
context.init(keyManagerFactory.keyManagers, trustManagerFactory.trustManagers, null)

val factory = context.serverSocketFactory

(factory.createServerSocket(LISTENING_PORT) as SSLServerSocket).use { serverSocket ->
    logger.trace("Listening on port: $LISTENING_PORT")

    // ...
}

Or in Java:

final char[] password = "yourPassword".toCharArray();

final KeyStore keyStore = KeyStore.getInstance(new File("yourKeystorePath.jks"), password);

final TrustManagerFactory trustManagerFactory = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
trustManagerFactory.init(keyStore);

final KeyManagerFactory keyManagerFactory = KeyManagerFactory.getInstance("NewSunX509");
keyManagerFactory.init(keyStore, password);

final SSLContext context = SSLContext.getInstance("TLS");//"SSL" "TLS"
context.init(keyManagerFactory.getKeyManagers(), trustManagerFactory.getTrustManagers(), null);

final SSLServerSocketFactory factory = context.getServerSocketFactory();

try (SSLServerSocket serverSocket = ((SSLServerSocket) factory.createServerSocket(LISTENING_PORT))) { 
    logger.trace("Listening on port: " + LISTENING_PORT);

    // ...
}

Answer 3

This will generate certificate:

keytool -genkey -keystore yourKEYSTORE -keyalg RSA

Enter yourPASSWORD and than start your server with ssl debug information(put yourKEYSTORE into directory with SSLServer.class):

java -Djavax.net.ssl.keyStore=yourKEYSTORE -Djavax.net.ssl.keyStorePassword=yourPASSWORD -Djava.protocol.handler.pkgs=com.sun.net.ssl.internal.www.protocol -Djavax.net.debug=ssl SSLServer

Than start your client(put yourKEYSTORE into directory with SSLClient.class):

java -Djavax.net.ssl.trustStore=yourKEYSTORE -Djavax.net.ssl.trustStorePassword=yourPASSWORD SSLClient