Designing a New PRNG

Re:Designing a New PRNG by matthewdgreen on Monday December 20, 2021 @06:12PM (#29631724)

I beg you to define what “good” means in a way that doesn’t imply security properties. And if you must demand security properties, god help you if you designed something that can’t provide them.

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Re:Designing a New PRNG by 317070 on Monday December 20, 2021 @06:56PM (#29632089)

Say I want to numerically approximate a high dimensional integral with MC sampling, say in a computational fluid dynamics simulation, or in a ray traced render.

For this, I need consequent samples from a PRNG to be really uncorrelated and fast. But there is no adversary relationship, so I don't need cryptographic strength. I just cannot have any spurious correlations between samples, as they might throw off convergence speed or worse, introduce error.

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Re:Designing a New PRNG by foxfluff on Monday December 20, 2021 @07:00PM (#29632117)

You don't need to define good in an absolute sense to see how one thing can be better than another.

The flaws of an MCG or LCG are easily witnessed, so it's totally fair for someone to go find out if it's possible to do better (i.e. remove obvious patterns, fix low period of low order bits, improve statistical quality) without sacrificing much performance; and indeed perhaps making it faster than a large-state LCG of comparable quality would be.

If you admit that there are any legitimate uses for non-cryptographic PRNGs then I guess a 32 bit MCG (or "42") is just perfect for you (otherwise you'd know what's better and you don't need to ask anyone to define good). You're easy to please.

If you think there are no legitimate use cases for these fast generators at all, then I'm sorry but a lot of people disagree and they will never rewrite their sims, noise generators, world generators, etcetra to use a CSPRNG no matter how much you whine about it.

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