Re: What the heck is this? Optical noise encryption? [and RNG probs]

Here's an exchange from sci.crypt in 1991 that's relevant to chaos and cryptography. A guy was using the logistic function as his RNG.

I did the exact same thing once; it took me a year or so to realize it was grossly insecure. Never trust an eighth-grade cryptographer. :-) As the sci.crypt FAQ says, there's no reason to expect a system which makes interesting pictures to be secure. The properties that chaotic systems display are nice, but they don't display them strongly enough -- look at iterated DES and you'll see some *real* sensitive dependence. Maybe with enough rounds and mixing... Eli ebrandt@hmc.edu