Re: Part 1: Ownership and Contracts

[Marcus Brinkmann]

At Wed, 3 May 2006 16:15:43 +0200,
Pierre THIERRY <address@hidden> wrote:
> 
> [1  <multipart/signed (7bit)>]
> [1.1  <text/plain; us-ascii (quoted-printable)>]
> Scribit Marcus Brinkmann dies 03/05/2006 hora 15:54:
> > "In either case, the mediating agent has, not exclusive, but still
> > quite complete ownership over the property that is part of the
> > contract (possession, use and disposal)."
> > 
> > So, the use of the word ownership is not completely appropriate here.
> > Maybe the word possession is better.
> 
> So could you elaborate on how those companies would possess the two
> processes, please.

I can't, because I do not claim that they possess the two processes.

BTW, I realized that the word "possess" is really ill-chosen as well.
I am still looking for a better word, but for now I would like to use
the word "hold".  Sorry for the confusion.

I do claim that they hold the property that is part of the contract.
This property is not the two processes involved in the contract, but
whatever they contribute to it (memory, etc).

However, your next paragraph makes it clear that your question is not
about what they hold, but why they hold it.  Let me answer this.

> IIUC, the TC chip doesn't gives anyone any right to your computer (I
> ignore the registers used to store encryption keys). It merely gives
> attestation of something. Nothing more.

This is only true if you believe that the chip does what the people
who build the chip claim that it does.  You only have their word for
it.

You may believe them.  You may have very good reasons to believe them.
But this does not mean that they are not, at least in principle, at
least nominally, in control.

I am not saying that they in fact, do have that control.  I am only
saying that they are the ones that could have that control.  This
makes them nominally, the one in control, even if they do not make use
of that.  Even if they _can not_ make use of it, because they took
precautions to make it impossible for them to exercise that control.
The reason is that you have no guarantee that they in fact, took these
precautions, and in fact, do not exercise that control.

Please reflect on the meaning of the word "trust" in "trusted
computing component".  It does not mean that the component is
"trustworthy".  It means that you _have_ to "trust" this component to
do the right thing, because it is the component that can break your
security policy.

Thanks,
Marcus