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Re: Trust and Transitivity

There are two different pictures here:

> 1. Skywalker signs Alice's key with tag X, so Skywalker trusts Alice in
> matters of X,
> 2. Skywalker meets Bob and Bob decides that he trusts Skywalker in matters
> of X.
> The question is: "Can you say that Bob trusts Alice in matters of X, based
> on the two assertions before?" 
> The answer is "No". Let's see why.

      trusts (1) Luke           trusts re X 
Bob  -----------------> Luke --------------> Alice
      (2) his certs

For (1) the trust isn't transitive. But For (2) we get a transitive picture:

              trusts re X
Bob ------------------------------------> Alice

> When I sign your key with the tag X, I am saying that I trust you to be
> (honest, knowledgeable, use-good-judgement) in matters of X.  I may not
> trust Khaddafi in such matters, or think that I do not, but if YOU do and
> you are basing your actions on his behalf, than I am implicitly trusting
> Khaddafi.  Had I known that you get your direction from Khaddafi, I might
> not have placed trust in you in the first place, but that is a another issue.

    trust re X           directions
I  ------------>  YOU  <------------ Khaddafi

This is not transitive (note the arrow points to the left). As said above,
I just have misplaced my trust and YOU missused it because you act on behalf
of Khaddafi.

read you later  -  Holger Reif
----------------------------------------  Signaturprojekt Deutsche Einheit
TU Ilmenau - Informatik - Telematik                      (Verdamp lang her)
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