Hello
I'm trying to understand to the PCR_Info_short structure returned within
TPM_QUOTE_INFO2 from Tspi_TPM_Quote() function.
Can somebody tell me what is the digestAtRelease hash computed from?
TPM Structures spec says: digestAtRelease : This SHALL be the digest of the PCR
indices and PCR values to verify when revealing auth data.
If I quoted over PCR17, then does that mean: digestAtRelease = sha1(17(index 1
byte) + pcr_value(20bytes)) ?? But this is obviously not correct, cause it
doesn't match with the output I get from Quote function.
Thanks
Sansar
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Here are the definitions from TSS and TPM specs:
struct tdTPM_PCR_INFO_SHORT{
TPM_PCR_SELECTION pcrSelection;
TPM_LOCALITY_SELECTION localityAtRelease;
TPM_COMPOSITE_HASH digestAtRelease;
} TPM_PCR_INFO_SHORT
typedef struct tdTPM_QUOTE_INFO2{
TPM_STRUCTURE_TAG tag;
BYTE fixed[4];
TPM_NONCE externalData;
TPM_PCR_INFO_SHORT infoShort;
} TPM_QUOTE_INFO2;
TSS_RESULT Tspi_TPM_Quote2
(
TSS_HTPM hTPM, // in
TSS_HKEY hIdentKey, // in
TSS_BOOL fAddVersion, // in
TSS_HPCRS* hPcrComposite, // in
TSS_VALIDATION* pValidationData, // in, out
UINT32* versionInfoSize, //out
BYTE** versionInfo // out
)
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