Java Cryptography

Using SafeTalk

The SafeTalk window is shown in Figure 10.1. The top part of the window is split between two text areas. You can type in the top text area. Whatever you type is transmitted to the person on the other end of your conversation. The lower text area displays the text that is received from the other end of the conversation.

Figure 10-1. The SafeTalk window

First-Time Setup

To use SafeTalk, you’ll first have to generate a key file. This involves picking a name for yourself and generating a key pair. SafeTalk will use this key pair to authenticate you and exchange a session key. SafeTalk expects ElGamal keys of any size in a key file called Keys.ser. You should create this file in the same directory as the SafeTalk classes. Because we are using the KeyManager class from Chapter 5, you can use KeyManager’s command-line interface to create a new key file. For example, I use the following line to create a key file for “Jonathan” with 512-bit keys:

C:\ java oreilly.jonathan.security.KeyManager -c Keys.ser Jonathan ElGamal 512
Initializing the KeyPairGenerator...
Generating the key pair...
Done.

If you need to review KeyManager or its command-line options, see Chapter 5.

This done, you can run SafeTalk by entering java SafeTalk. The SafeTalk window will pop up and will greet you by name.

Exporting a Key

Once you’ve generated a key file, you’ll need to export your public key and distribute ...