There have been some discussions on sci.crypt within the past few months on nonlinear/chaotic algorithms and their use in cryptography. Fractal cryptography sounds like it might be related. The problem is that unless an algorithm was SPECIFICALLY DESIGNED to prevent an intelligent adversary from defeating it, the chances of it being an effective cryptosystem are limited. Just because nonlinear systems produce complex-looking results does not mean that these results are unpredictable given enough data. Now, maybe this particular fractal cryptosystem idea will actually work well. I don't know; I haven't seen it. But the point is that these complex types of systems have not provided a good foundation for crypto- graphy in the past. sci.crypt messages are available on (at least) ripem.msu.edu, in /pub/crypt/sci.crypt. In that directory there is a file "subjects", which lists all the subject lines by message number, as well as a collection of files each of which holds a couple of months' worth of messages. You can grep the subjects file to find those messages which might be i{terested. The archives appear to go back a couple of years. Hal