In the first article of this series, Tim Matthews described how JavaSoft is developing a Java Cryptography Architecture (JCA) and extensions (Java Cryptography Extensions, or JCE). He described their contents and structure in the java.security package, and outlined their uses. In the second installment, I presented some actual code using the base functionality in the JCA. This third article describes programming using the JCE and multiple providers.

After reading this article, you will, I trust, be able to write a program in Java (an application or applet) that can encrypt or decrypt data using DES and create an RSA digital envelope with the extensions package. Beyond the specific example presented here, though, I hope you will understand the JCE model enough to be able to quickly write code for any operation in the package, and to be able to use multiple providers.

Before beginning, however, it is important to note that the security packages are not part of the JDK 1.0.2, only JDK 1.1 and above. Furthermore, there are significant differences between the security packages in JDK 1.1 and 1.2. This article (and the previous) describes features in 1.2. If you have not yet left 1.0.2 behind, now would be a good time to do so. After all, with 1.2, you are not only getting the security packages, you are also getting improved cloning, serialization and many other features.

There is an important change from JDK 1.1 to 1.2, the JCE is in a different package.