[E-Lang] Irreversible delegation, was: draft statement of con sensus

Karp, Alan alan_karp@hp.com
Thu, 08 Feb 2001 20:56:55 -0800

[Alan, I received your message as an attachment named smime.p7m.  Using 
emacs I was able extract the following plain text from the midst of other 
stuff, so I'm resending it to the list "as" you.  Hope this is ok.  --MarkM]

Isn't rights amplification an issue?  Here I've set up a scenario in
which one of the conspirators loses any benefit obtained by giving up
the power irrevocably.  Hence, Alice "prevents" Bob from doing
irrevocable delegation.  I'd also like to turn the story around, so that
the conspirator benefits only by giving up the power irrevocably.  That
should have the same result as Alice requiring Bob to delegate to Mallet
irrevocably.  Unfortunately, I don't see how to do it.

Bob has the right to the can; Carol has the right to the can opener.
Bob and Carol never heard of each other.  Bob is willing to proxy for
Mallet; Carol is willing to proxy for Mallet.  The tuna is safe from all
three.  Bob gives Mallet the right to the can.  Mallet can ask Carol to
combine her right to the can opener with his newly obtained right to the
can.  Now, the three conspirators can make their tuna casserole.  (Side
question.  Doesn't the SPKI do not delegate bit prevent this misuse?)

Note that Mallet and Carol have no need to invite Bob to the banquet.
Bob can't revoke the privilege he gave to Mallet, so he has no recourse.
If there is no honor among thieves, then Bob won't give Mallet the right
to the can.  Why should Mallet get all the goodies?  (I'm assuming no
side payments.  Is that fair?)  Alice's tuna is protected because the
only way that Bob can give Mallet what he needs to get the tuna is to do
so irrevocably.

Is this reasonable?  Can anyone see how to turn the story around so Bob
only benefits from irrevocable delegation?