OK thanks.  So TPM doesn't care, Trousers does, or, Trousers does it a
specific and "correct" way for interoperability.

I'm using Trousers, so as you point out, this is done for me.  I am
actually working on the code for the PCA side right now, and got a little
confused; I don't have to generate this hash from that end, I don't think,
only use it to verify the TPM_ID_PROOF payload.

Thanks,
-Tadd

On Thu, Apr 7, 2016 at 12:27 PM Phil Lacroute <[email protected]>
wrote:

> Tadd,
>
> The TPM doesn’t care what values are hashed into TPM_CHOSENID_HASH, but if
> you require interoperability with a TCG-compliant privacy CA then the
> privacyCA value should be a marshaled TPM_PUBKEY structure.  Part 2 2.1
> Representation of Information describes the basic rules for marshaling and
> Part 2 10.5 TPM_PUBKEY describes this structure.
>
> An easier reference for the marshaling code is the TrouSerS source (
> https://sourceforge.net/projects/trousers/files/trousers/).  See
> src/tspi/tspi_aik.c:Tspi_TPM_CollateIdentityRequest() which shows how to
> compute the ChosenID hash.
>
> Phil
>
> > On Apr 7, 2016, at 6:11 AM, Ken Goldman <[email protected]> wrote:
> >
> > On 4/6/2016 9:32 PM, Tadd Seiff wrote:
> >> Hi all,
> >>
> >> I need help understanding the TPM_CHOSENID_HASH structure in the TPM
> >> spec, section 12.4 in the structures document for 1.2.  It says:
> >>
> >> TPM_CHOSENID_HASH = SHA(identityLabel || privacyCA)
> >>
> >> 1.) What does the || notation suggest here?  Concatenation? Or'ing?
> >
> > From Part 1:
> >
> > "Throughout all parts of the specification the characters x1 || x2 imply
> > the concatenation of x1 and x2."
> >
> >> 2.) The privacyCA element is actually a structure, so, what do I do with
> >> that?  Just use the whole structure as a byte array?
> >
> > The way I read Part 3 15.1 TPM_MakeIdentity, the TPM doesn't care.  The
> > actual value is between you and the privacy CA.
> >
> > I'm not an expert at this section.  Let's see what others say.
> >
> >
> >
> >
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> > [email protected]
> > https://lists.sourceforge.net/lists/listinfo/trousers-users
>
>
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