CDR: Re: one time pad and random num gen

[Steve Furlong]

Bill Stewart wrote:
> By contrast, if you've got a pseudo-random number generator,
> which uses some mathematical process to generate the numbers,
> knowing bits 1...I-1 tells you something about bits I...N,
> so if the message has structure to it, you can often exploit it.

Isn't a good definition of a cryptographically-strong PRNG that even if
you know bits 1..I-1, you still don't know anything about bit I? (Unless
you know the internal state of the PRNG, of course.) A c-strong PRNG
shouldn't be susceptible to any currently known analyses.

Perhaps that's just a theoretical definition, and no existant PRNGs come
close. But I thought some good ones were out there.


Ta,
SRF

-- 
Steve Furlong, Computer Condottiere     Have GNU, will travel
   518-374-4720     sfurlong at acmenet.net