title: network communication encryption in java
body: <p>A friend and me are working on a Java Game with a client/server - architecture.
  It is working well, but i ran into a problem.
  We use TCP Sockets for networking between server and client.
  Our network protocol isnt encrypted and can just be read by anone who bothers to watch the stream. </p>
  
  <p>We thought about how we could apply some kind of cryptography to it to hide login information and prevent people to write their own clients. But basic things like adding/substracting bytes seems pretty easy to figure out.</p>
  
  <p>What are the usual methods used to encrypt network communication for games( or at least game login information )? And having written the server and client in java, are there any useful java libraries?</p>