Le 16/11/2012 17:35, Florian Bösch a écrit :
On Fri, Nov 16, 2012 at 5:20 PM, David Bruant <bruan...@gmail.com
<mailto:bruan...@gmail.com>> wrote:
That'd be a nonsense to add seeding in my opinion. If you want
security, you don't want to take the risk of people seeding and
loose all security property. If it's for debugging purposes, the
seeding should be part of a devtool, not of the web-facing API.
I agree that in the crypographic context seeding might not make sense
(or even guarantees about repeatability).
The purpose of the proposal of a fast, reliable, statistically sound,
repeatable, seedable PRNG in JS however is not to do cryptography. It
would be to be able to perform procedural computation repeatably
regardless of machine, VM, optimization and vendor differences. An
example: Say you wanted to do a procedural universe consisting of 1
million stars. At 3 cartesian coordinates per star and at each
component having 8 bytes, you'd get 22MB of data. If you want to share
this galaxy with anybody you'll have to pass them this 22mb blob. If
you want multiple people in the same galaxy, you have to pass them
that blob.
If you want repeatable, you actually don't want random (as your title
suggests) but PRNG very specifically ("pseudo" being themost important
part). In that case, I feel writing your own PRNG will be almost as fast
as a native one with nowadays crazy JIT. Just write an algorithm that
you're satisfied and pass around the algo and any parametrization you
want. I feel it would solve your use case.
It takes about 0.7 seconds in C to generate 3 million statistically
sound random numbers for longs.
Do you have measurements of how much the same algo takes in JS?
David
