L12-TCPA-PALLADIUM Datasheet, PDF (10/12 Pages) List of Unclassifed Manufacturers – TCPA and Palladium

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8 POLICY ISSUES
How do we do this?
• Use the PCR value to “brand” encrypted secrets with the identity of the code that “owns”
them
• Owners of secrets can also designate alternate recipients (necessary for update and Palladium
migration)
Attestation
Attestation lets a remote client know what software is running. This authentication technology, is
more than a “simple signing;” Attestation enables authentication of a software configuration (nexus,
application, process).
• Code authenticates itself using the SSC quote function:
– Quot(S) → Sign[S|P CR]
• This provides a protocol building block:
– For example, in a Server/peer protocol
∗ The server checks the signature, checks certificates on signing key, checks nexus digest
is as expected
∗ Then, it knows the client is a “MS Nexus on Acme Trusted Platform”
• Implementation: RSA using SSC key pair
• No anonymity at this low level. Can only use the hardware key ONCE per power cycle.
To preserve anonymity, use the hardware key to create pseudo-identities to provide indi-
rection/anonymity while still providing platform attestation. Being able to create pseudo-
identities requires the presence of trusted third parties which do not exist at present. Microsoft
is looking into encouraging such markets.
8 Policy Issues
Some of the technical issues we have to solve are policy issues.
You want to have a piece of technology that you can hold up any time anyone starts to complain
about social problems. For instance, you’re worried about a child viewing pornography on net?
Don’t make pornography illegal; make a chip that protects kids.
• So how do we build an attestable TCB (trusted computing base): open, auditable, and com-
prehensible?
• Since the Palladium RSA key is unique what steps should we take to defend against traffic
analysis and behavior?