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Re: [Rats] TPM background for RIV

Michael Richardson <mcr@sandelman.ca> Tue, 25 August 2020 22:29 UTC

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From: Michael Richardson <mcr@sandelman.ca>
To: Ira McDonald <blueroofmusic@gmail.com>, "rats@ietf.org" <rats@ietf.org>
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Date: Tue, 25 Aug 2020 18:29:25 -0400
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Subject: Re: [Rats] TPM background for RIV
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Ira McDonald <blueroofmusic@gmail.com> wrote:
    > Small note:  Although you say each TPM has at least 16 PCRs, in fact the
    > TPM 2.0 Mobile Common Profile
    > (2015) only requires the implementation of one SHA-256 bank of 8 PCRs (a
    > SHA-1 bank is prohibited here).
    > That design choice was made to avoid the squabbles over the inconsistent
    > usage of PCR8 through PCR15
    > across various TPM 2.0 profiles.

I just want to understand.
TPM 2 mobile, only requires PCR0-7.  It doesn't forbid PCR8->15 though?
Do devices tend to implement them all?  Or?

So what do the profiles do now?

What is the impact on RIV?

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]   Michael Richardson, Sandelman Software Works        |    IoT architect   [
]     mcr@sandelman.ca  http://www.sandelman.ca/        |   ruby on rails    [

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