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Re: radix tree implementation for quota ?
On Mon, Nov 29, 2010 at 11:12:21AM -0500, der Mouse wrote:
> > If the keys are controlled by a third party, it is very easy to
> > degrade the performance to a linear list.
> Sure, but that's not a useful remark. It's equally true of (n*K)>>32,
> or for that matter any other easily invertible hash function. If the
> bucket count is small enough to make guessing feasible for the
> attacker, it's true of any hash function cheap enough to be useful as a
> hash function.
Only if you keep K fixed. If you follow the "rehash with different K on
high number of collissions" scheme, it is resilient to such attacks.
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