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

[Eli Brandt <ebrandt@jarthur.cs.hmc.edu>]

> 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