[messaging] Value of deniability

David R. Andersen k0rx at RXcomm.net
Thu Dec 11 09:53:19 PST 2014

Lots of hating on plausible deniability on this list...

I can think of a number of use-cases where deniability is 
important - none of which involve lying in court or sociopathy
or ... One example:

When I purchased my last car, I engaged in negotiation
regarding its price. That negotiation involved some
back-and-forth communication between myself and the
dealership. Its my feeling that it would be inappropriate
for the dealership to be able to turn to a third party
and say "here's an undeniable transcript of Dave's
negotiation with us," and I suspect the dealership would
feel the same way. Deniability to third parties is
important in at least some negotiations.

On the other hand, both the dealership and I have every
interest in the result of those negotiations, a bill-of-sale
and a title, being authenticated and recorded according
to local laws and customs.

If deniability is incorporated at the protocol level, then
different communication systems can make use of it, or not,
as appropriate for their market. Luckily for us, two of
the currently-used one-to-one protocols provide such
deniability. OTR requires an extra step at the end for this,
and with Axolotl it just works.


int x=90560580,y=32678;main(){putchar(x);x>>=y&7;y>>=3;return y?main():0;}

Quis custodiet ipsos custodes?

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