TPM QUOTE 
TOOLS(8)														TPM QUOTE TOOLS(8)

NAME

       TPM Quote Tools

PROGRAMS

       tpm_mkuuid, tpm_mkaik, tpm_loadkey, tpm_unloadkey, tpm_getpcrhash, tpm_updatepcrhash, tpm_getquote, tpm_verifyquote

DESCRIPTION

       TPM Quote Tools is a collection of programs that provide support for TPM based attestation using the TPM quote operation.

       A  TPM  contains  a set of Platform Configuration Registers (PCRs).  In a well configured machine, some of these registers are set to known
       values during the boot up process or at other times.  For example, a PCR might contain the hash of a boot loader in  memory  before  it	is
       run.

       The  TPM  quote operation is used to authoritatively verify the contents of a TPM's Platform Configuration Registers (PCRs).  During provi-
       sioning, a composite hash of a selected set of PCRs is computed.  The TPM quote operation produces a composite hash that  can  be  compared
       with the one computed while provisioning.

       To  use the TPM quote operation, keys must be generated.  During provisioning, an Attestation Identity Key (AIK) is generated for each TPM,
       and the public part of the key is made available to entities that validate quotes.

       The TPM quote operation returns signed data and a signature.  The data that is signed contains the PCRs selected  for  the  operation,  the
       composite  hash	for  the selected PCRs, and a nonce provided as input, and used to prevent replay attacks.  At provisioning time, the data
       that is signed is stored, not just the composite hash.  The signature is discarded.

       An entity that wishes to evaluate a machine generates a nonce, and sends it along with the set of PCR used to generate  the  composite  PCR
       hash at provisioning time.  For this use of the TPM quote operation, the signed data is ignored, and the signature returned is used to val-
       idate the state of the TPM's PCRs.  Given the signature, the evaluating entity replaces the nonce in the signed data  generated	at  provi-
       sioning	time,  and  checks to see if the signature is valid for the data.  If so, this check ensures the selected PCRs contain values that
       match the ones measured during provisioning.

       A typical scenario for an enterprise using these tools follows.	The tools expect AIKs to be referenced via one enterprise-wide Universally
       Unique Identifier (UUID).  The program tpm_mkuuid creates one.

       For  each  machine  being  checked,  an	AIK  is  created using tpm_mkaik.  The key blob produced is bound to the UUID on its machine using
       tpm_loadkey.  The public key associated with the AIK is sent to the entities that verify quotes.  Finally, the expected PCR composite  hash
       is obtained using tpm_getpcrhash.  When the expected PCR values change, a new hash can be generated with tpm_updatepcrhash.

       The  program  to  obtain  a  quote,  and  thus  measure the current state of the PCRs is tpm_getquote.  The program that verifies the quote
       describes the same PCR composite hash as was measured initially is tpm_verifyquote.

SEE ALSO

       tpm_mkuuid(8), tpm_mkaik(8), tpm_loadkey(8), tpm_unloadkey(8), tpm_getpcrhash(8), tpm_updatepcrhash(8), tpm_getquote(8), tpm_verifyquote(8)

								     Oct 2010							TPM QUOTE TOOLS(8)