[cap-talk] Delegating Responsibility in Digital Systems:Horton's "Who Done It?"

[Toby Murray]

On Fri, 2007-06-08 at 00:52 +0000, Karp, Alan H wrote:
> > Scribit Karp, Alan H dies 07/06/2007 hora 15:47:
> > > Each request from a different responsible party comes through a
> > > different forwarder under Carol's control.  That provides Carol
> > > undeniable authentication.  However, Carol can't prove that 
> > to anyone
> > > else because the forwarder is under her control.  For example, she
> > > could have sent the request herself.
> > 
> > So if I understand this correctly, for the authentication to be
> > undeniable to other subjects than Carol, the forwarder must 
> > be under the
> > control of a third party trusted by those subjects, and not under
> > Carol's control, mustn't it?
> 
> Or signed by the sender.

Using a key that everyone can authenticate, which may require a TTP
anyway to authenticate the key.