[tor-dev] Proposal 178: Require majority of authorities to vote for consensus parameters

Nick Mathewson nickm at freehaven.net
Wed Mar 2 07:06:42 UTC 2011

On Tue, Feb 22, 2011 at 1:34 AM, Sebastian Hahn <hahn.seb at web.de> wrote:

> Design:
> When the consensus is generated, the directory authorities ensure that
> a param is only included in the list of params if at least half of the
> total number of authorities votes for that param. The value chosen is
> the low-median of all the votes. We don't mandate that the authorities
> have to vote on exactly the same value for it to be included because
> some consensus parameters could be the result of active measurements
> that individual authorities make.

This is possibly bikeshed, but I would suggest that instead of
requiring half of  existing authorities to vote on a particular
parameter, we require 3 or more to vote on it. (As a degenerate case,
fall back to "at least half" if there are fewer than 6 authorities in
the clique.)

I think we don't want the number to be _less_ than 3, since 3 is the
smallest number of parties who can come up with a low-median that
isn't just the diktat of a single member (1 party), or as low as
either member wants it to be (2 parties).


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