[cap-talk] Definition of "authority"? r.e. technical term for computer systems

[Jed Donnelley]

At 07:49 PM 1/19/2008, Karp, Alan H wrote:
>...
>Bob has permission to talk to Alice.  Alice has permission to write 
>even and odd integers into the file.  Bob sends messages to Alice 
>requesting that integers be written to the file.  Alice only writes 
>the even integers that Bob requests.  Alice uses her permission and 
>behavior to grant Bob authority to write even integers to the file.

In the above you say, "Bob has permission to talk to Alice."
To me this is a meaningless thing to say about the permission
that Alice granted to Bob.  Capabilities always grant the
permission to communicate to the server of the capability.
 From my perspective the meaningful thing to say about the
"permission" Alice granted to Bob is that Alice granted Bob
the 'permission' to write even integers to the file.

If you disagree, why did you say that "Alice has permission
to write even and odd integers into the file."?  To be
consistent, shouldn't you say that Alice has permission
to talk to the file server and that Alice has the
'authority' to write integers to the file?

If I were to look at the details of the capability that
Bob has from Alice, I might see that it has the "even"
number access right vs. another capability from Alice with
the "odd" number access right.  If both "access right"s
were turned on then I suppose you could say that Alice
granted to Bob both the permission to write even
integers and the permission to write odd integers.
In that case would you say that Bob has the "authority"
to write any integers - namely the sum of the two
'permission's?

I thought the idea of 'authority' as MarkM uses it in
his thesis was intended to be deeper than that.  Namely
that it relates to ultimate actual authority vs.
directly granted intended authority.

Suppose, for example, there was a bug in the file
server that allowed one to write ASCII text to it
in some obscure invocation.  In that case if something
about the invocations that Alice granted to Bob might
result in Bob being able to write some ASCII text
to the file, would Bob have the "authority" to
write ASCII text even though he nominally only
was granted 'permission' to write even integers?

I admit I'm reaching here.  I still don't get it.
Maybe a telephone call would be the best way to
clear this up?  If I could understand I'd be happy
to share that understanding with others on the list.

--Jed  http://www.webstart.com/jed-signature.html