Interactive demonstrations

In this section, we show how some concepts in e-commerce and international trade work. The demos mostly use scripts, so, if your browser does not support scripts, then - sorry, but you can't play with these demos. Also, we no longer support Netscape 4.x browsers. We apologise for any inconvenience.

This demonstration explains how digital signatures work.

It starts by explaining (briefly) some terminology, and then offers an interactive presentation of how cryptography can be used to prove the authenticity and integrity of a message. After that some more explanation about public key cryptography, and then a chance to see the creation and verification of a digital signature, with the opportunity to play hacker as well as sender and receiver.

Please note that the crypto algorithms used were created for demonstration purposes only and are by no means secure.

An introduction to signal flags and how they are used.

The demo shows how to use the signal flags, the meaning of the substitute pennants and the use of the answer pennant, and also provides a chance to test your skills in recognising flags...

A concentrated explanation of the German Enigma crypto machine, together with a virtual implementation of one. It produces authentic crypto output... just as safe as the original.