I've written a number calculator applet as a number theory teaching tool. It exposes most of the functionality in the Java 1.1 (and later) BigInteger package, including prime checking and modular arithmetic. One of its goals is to let people try out various cryptographic calculations by hand. For example, I try to describe a manual D-H key exchange procedure. The applet and documentation is at http://world.std.com/~reinhold/BigNumCalc.html Unfortunately, Netscape 4.7 and earlier do not support Java 1.1, so you will need Internet Explorer 4.5 or later or the new Netscape 6.0. I've tested the applet using IE 5.0 and 5.5 on Windows 98 and IE 4.5 (MRJ) on the Mac. I'd like to get some feedback before I try to distribute the applet more widely. Comments, bug reports and test results on other browser/platform combinations would be most helpful. Also I'd be interested in suggestions as to a suitable open source repository for the Java source code. Enjoy, Arnold Reinhold
