[cap-talk] Mandatory Access Control (was: What's "Discretionary Security")

[John McCabe-Dansted]

On 1/3/07, Jed Donnelley <capability at webstart.com> wrote:
>  Mandatory: Required or commanded by authority; obligatory.
>
>  Discretionary:  Left to or regulated by one's own discretion or judgment.
>
>  I still regard these terms as nonsense when applied to access control
> where, as I say, the controller of the access has discretion and the
>  controlled views the access control as mandatory - in whatever
> scheme of labels, ACLs, capabilities, etc.

I think that they are referring to discretionary with respect to the
users who "own" or have access to certain documents. In a
discretionary access system I can send any data I possess to any other
user of the system. In a MAC system this might fail if the recipient
has a lower clearance than I do. I imagine that in a cap system this
would mean that some powerboxes cannot communicate bidirectionally
with other powerboxes on the same system, or that the powerboxes are
in some way trusted to limit delegation of confidential data.

-- 
John C. McCabe-Dansted
PhD Student
University of Western Australia