Linux-kernel mailing list archive 2000-04,: Re: Intel 810 Random Number Generator

# Re: Intel 810 Random Number Generator

Frank v Waveren (fvw@var.cx)
Mon, 24 Jan 2000 16:08:31 +0100

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On Mon, Jan 24, 2000 at 10:02:54AM -0500, Jeff Garzik wrote:
> Frank v Waveren wrote:
> > Am I missing something here? I thought that you could mix all the non-random
> > numbers you want into the entropy pool (long live xor), and it will never make
> > the entropy worse? So I'd say mixing in the RNG won't do any harm, so why not?
>
> Read the intro text in drivers/char/random.c...
>
> If the RNG provides a lot more data than other entropy sources, it can
> throw things out of whack.

Hmm, interesting. I quote (in case someone else is interested)

* outside observer to measure. Randomness from these sources are
* added to an "entropy pool", which is mixed using a CRC-like function.
* This is not cryptographically strong, but it is adequate assuming
* the randomness is not chosen maliciously, and it is fast enough that
* the overhead of doing it on every interrupt is very reasonable.

Why not use XOR, which is 'pretty quick' too, and *really* doesn't care if
your mixing in your bookmarks file or radioactive decay data?

    --

    			Frank v Waveren
    			fvw@var.cx
    			ICQ# 10074100

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