Subject: [Secdispatch] some more comments received on Re: richardson-secdispatch-idevid-considerations

From: Michael Richardson <[email-masked]>
Date: Wed, 26 Aug 2020 19:50:50 -0400

Laurence Lundblade <[email-masked]> wrote:
    > I think there is an enormous difference between these two:

    > 1) Trust Anchor where public key is in the device
    > - Code signature verification
    > - Trusted / secured / xxx boot

    > 2) Trust Anchor where private key is in the device
    > - RATS / EAT
    > - IDevID
    > - (also DRM)

Absolutely.
  1) => TRUST ANCHOR
  2) => ROOT OF TRUST

I'm not keen on the second term, as it confuses many.
I would love another term that is less TCG/RATS specific.

    > I’m not sure I’d even call the second one a trust anchor or the RFC
    > 4949’s definition of trust anchor aligns with it. At Qualcomm we called
    > the second one “key provisioning”.

I never tried to call them both trust anchors!
If I did, please tell me where, so I can correct it.

But, I want to note that *BOTH* involve the manufactuer maintaining some kind
of PKI (whether it's RFC5280/PKIX based, or CWT/EAT based, or OpenPGP) to
sign the public key part.

For IDevID, the infrastructure needs to sign the certificate loaded.

For code-signing trust-anchors, the infrastructure needs to maintain the
signing keys.

In both cases, there are keys at the "factory" (or "key provisioning
facility" as we wrote this week in the RATS architecture).

--
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