Book Image

Learning Network Programming with Java

Book Image

Learning Network Programming with Java

Overview of this book

Network-aware applications are becoming more prevalent and play an ever-increasing role in the world today. Connecting and using an Internet-based service is a frequent requirement for many applications. Java provides numerous classes that have evolved over the years to meet evolving network needs. These range from low-level socket and IP-based approaches to those encapsulated in software services. This book explores how Java supports networks, starting with the basics and then advancing to more complex topics. An overview of each relevant network technology is presented followed by detailed examples of how to use Java to support these technologies. We start with the basics of networking and then explore how Java supports the development of client/server and peer-to-peer applications. The NIO packages are examined as well as multitasking and how network applications can address practical issues such as security. A discussion on networking concepts will put many network issues into perspective and let you focus on the appropriate technology for the problem at hand. The examples used will provide a good starting point to develop similar capabilities for many of your network needs
Table of Contents (16 chapters)
Learning Network Programming with Java
Credits
About the Author
About the Reviewer
www.PacktPub.com
Preface
Index

Symmetric encryption client/server


This section demonstrates how to use symmetric encryption/decryption in a client/server application. The following example implements a simple echo client/server allowing us to focus on the basic process without digressing into specific client/server issues. The server is implemented with the SymmetricEchoServer class and client using the SymmetricEchoClient class.

The client will encrypt a message and send it to the server. The server will then decrypt the message and send it back in plain text. The response can easily be encrypted if needed. This one-way encryption is sufficient to illustrate the basic process.

When running the applications that are discussed in this chapter in Windows, you may encounter the following dialog box. Select the Allow access button to allow the applications to run:

We will also use the SymmetricKeyStoreCreation class that was developed in symmetric encryption techniques.

Symmetric server application

The symmetric server is declared...