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

Sebastian Hahn hahn.seb at web.de
Mon May 2 09:23:02 UTC 2011

On Mar 2, 2011, at 8:06 AM, Nick Mathewson wrote:

> 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.)

Hrm. I'm not too happy with this, unless we also include a way for a
majority of authorities to prevent voting on that parameter altogether.
Doing the design as presented above would then be simpler.

> 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).

Yes, anything less than 3 is bad imo.


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