NODE e0401029that cipher I wrote
Tyler Yip - UnixWeenie(tm) <davros@ecst.csuchico.edu>Sat, 19 Jun 93 02:34:15 PDT
Peter Davidson: thanks for the cycle tester!!!!! hadn't thought about
testing a generator. As for those generators, they are seeded with the key,
but, I messed it up by getting the primes in the wrong order.
What characteristics of the multiplier and modulator provide large periods?
--
Tyler Yip, UnixWeenie(tm) \ God put me on Earth to accomplish a certain
email: davros@ecst.csuchico.edu \ number of things. Right now I am so far
California State University, Chico \ behind I will never die. -Calvin & Hobbes
NODE 50517258Re: that cipher I wrote (pseudo random generators)
gnu (John Gilmore)Sat, 19 Jun 93 18:57:35 PDT
> What characteristics of the multiplier and modulator provide large periods?
Don't bother with looking for a large period (though Knuth spends
about half a book on pseudorandom number generators). The problem is
that the sequence is predictable. Given ten sequential values from
anywhere in the sequence, I think there are algorithms that will
determine the sequence. This is from dim recall of some Crypto '90
presentations. Perhaps someone has the papers in front of them, or
can re-derive the results?
Given plaintext XOR'd with a sequence, you can make pretty good guesses at
ten values in the sequence, and if you have to try a few thousand guesses,
it will still only take minutes or hours to crack.
John