[Bill Payne's's mailing list pruned back to cypherpunks only]

Ted Lewis told me that they now use the gfsr at LANL for its nuclear bomb=20 simulations.

http://av.yahoo.com/bin/query?p=3Dgfsr&hc=3D0&hs=3D0=20

But this is how the mess got started. Me making contact with a Japanese=20 professor who developed a new method for selecting the binary seed matrix for the gfsr.

Is that to speed it up, so you don't have to initialize it by spinning through a bunch of initial iterations? Turns out there's a time-memory tradeoff, where if you do a recursion relationship on where you want it to start, you can set it up in log2 time and come out with the same starting point you would have by spinning: the recursion equations cancel nicely and it boils down to something manageable. I think other people have initialized it with another PRNG with good success. I <know> that's not classified, since I came up with the recursion shortly after the Lewis & Payne paper on GFSR came out -- JACM, wasn't it? I never got around to writing it up. Jim Gillogly