The latest release of Java for Panther, 1.4.2_03-117.1, incorporates for the first time the Java Cryptography Extension (JCE) package. But there's a catch: by default, to be internationally importable, the package is limited to "strong" (read: weak) encryption. To enable unlimited (read: strong) encryption capabilities go to this link, and scroll down to "Other Downloads" and download the file "Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files 1.4.2."
After unzipping, install the two files (you will need root or admin access) "local_policy.jar" and "US_export_policy.jar" into /System -> Library -> Frameworks -> JavaVM.framework -> Versions -> 1.4.2 -> Home -> lib -> security, replacing the originals (you should back them up first!). Then fix permissions and ownership as necessary. Voila!
Mac OS X Hints
http://hints.macworld.com/article.php?story=20040606062522906