To demonstrate how JSSE works in the real world, we're going to employ a simple distributed whiteboard system. The whiteboard is a program that lets users write text messages onto a blank canvas. These text messages then appear on the canvases of other users who are connected to the same whiteboard server. This allows people in different locations to communicate.

Because we're more interested in the security aspects of this program than in the whiteboard functionality itself, we'll keep the application very simple. Our whiteboard will allow users to create text messages, but it will not allow them to delete messages. Mostly, we'll just pay attention to how the whiteboard implements JSSE, thus ensuring that messages can be securely sent between users.

In this section we discuss the basic structure of the whiteboard and how it implements JSSE. In the next section, we'll begin working directly with the code for the whiteboard application.