It is known that is possible to define an NV Extend Index which has a behaviour similar to a PCR (Platform Configuration Register) and it is possible to modify it using TPM2_NV_Extend() operation.

Now if I want to use this space to increment the number of PCRs is it possible to perform a quote operation over this space in the same way I normally do with PCRs ?

Because I didn't find anything in the specifications from Trusted Computing Group.

Usually I program using the ESYS API and the quote operation is incompatible with NV index because of the different structures used.

  • Updates: In order to substitute a quote operation two different operation can be applied to the NV hybrid Indexes. The first one is to use TPM2_GetSessionAuditDigest a sort of generalization of the TPM2_Quote operation. The second one instead consist in the utilization of the TPM2_Certify operation. Accordingly to scenario one can be better than the other one – Andrew May 20 at 15:05

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