Re: I've often wondered

Karl J. Runge (runge@redhook.llnl.gov)
Thu, 24 Apr 97 00:20:53 PDT


> From: Darrell Kindred <dkindred@cmu.edu>
> Subject: Re: I've often wondered

On Thu, 24 Apr 1997, Darrell Kindred <dkindred@cmu.edu> wrote:
> There's no need for the servers to communicate directly.
> The DESCHALL organizers can just inform organizers of the
> other efforts that DESCHALL will first search all keys whose
> first hex digit is (say) 2 or D (since we search
> complementary pairs). Once we finish that, we'll announce
> that we're starting some other (unclaimed) digit.
>
> Manually divvying up the keyspace at this granularity should
> require only very simple modifications to keyservers, and it
> will become increasingly important that we do this to avoid
> wasted work. I hope the arrangements will be made soon (if
> they haven't been already).

If the two keyservers run at equal rates the average amount of time
longer it takes for uncoordinated keyservers vs. coordinated keyservers
is 33% longer.

The general formula for k equal keyservers is 2k/(1+k) for the slowdown
factor. (I.e ave_time_uncoordinated / ave_time_coordinated). The factor
is 2 for k -> infinity (e.g. the ByrdDES and DESKR groups).

A calculation I have worked out in a notebook but not coded up to get the
numbers for is computing (ave_time_uncoordinated/ave_time_coordinated)
not assuming a constant key rate, but instead a rapidly growing one.
We've had exponential growth with doubling time of 7-8 days for well
over a month now, I hope it lasts a good while longer.

My intuition is that (ave_time_uncoordinated/ave_time_coordinated)
is even less than 1.33 for the case of rapid rate increase.

Just my $0.02.

Karl

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