Other uses of TCPA

[James A. Donald]

    --
James Donald writes:
> > I can only see one application for voluntary TCPA, and that is 
> > the application it was designed to perform:  Make it possible 
> > run software or content which is encrypted so that it will  
> > only run on one computer for one time period.

On 3 Aug 2002 at 20:10, Nomen Nescio wrote:
> You've said this a few times, and while it is a plausible goal  
> of the designers, I don't actually see this specific capability 
> in the TCPA spec, nor is it mentioned in the Palladium white  
> paper.

Think about it.

> For TCPA, you'd have to have the software as a blob which is  
> encrypted to some key that is locked in the TPM.  But the  
> problem is that the endorsement key is never leaked except to  
> the Privacy CA ....

(Lots of similarly untintellible stuff deleted)

You have lost me, I have no idea why you think what you are  
talking about might be relevant to my assertion.

The TPM has its own secret key, it makes the corresponding public 
key widely available to everyone, and its own internal good known
time.  So  when your customer's payment goes through, you then
send him a  copy of your stuff encrypted to his TPM, a copy which
only his TPM  can make use of.  Your code, which the TPM decrypts
and executes,  looks at the known good time, and if the user is
out of time, refuses to play.   

    --digsig
         James A. Donald
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