Transitive trust and MLM

[E. ALLEN SMITH]

From:	IN%"eli+ at GS160.SP.CS.CMU.EDU" 10-MAY-1996 17:48:49.87

>Each signature has an /a priori/ probability p of correctly indicating
>validity, but these probilities are not independent at all: this key
>isn't valid, period.  If one certifying signature is incorrect, all
>others on the same key must be, and vice versa -- about as correlated
>as they come.

	The different paths going through those different signatures will be
correlated/non-independent, yes.... but that isn't the problem unless you're
considering multiple paths (in a more complicated version).

>To limit transitivity, constrain the path length.  This limits key
>reachability too, but I think we agree that it's essential in the real
>world.  (It should also make the math simpler!)  The model generalizes
>to non-binary conceptions of trust, but I don't think these can
>rehabilitate transitivity.  Hmm, there are some possible approaches,
>though.

	IIRC, there have been some sociological studies showing that _everyone_
is linked through 6 or so people. Now, there's the question of whether you
_need_ to be linked to _everyone_ - just everyone with whom you want to do
business (e.g., excluding authoritarian types doing a sting). It does come back
to the elite vs masses distinction; I see nothing wrong (and am in favor of)
separation of the elite from the masses.
	-Allen