Patent ID: 8028172

Claim:
A computer readable medium, wherein the computer readable medium is not a transitory signal, bearing instructions for a computer, said computer comprising a Hardware Security Module (HSM) that accesses recorded values, compares submitted values indicative of at least one measurement to the recorded values, and releases a sealed secret (a released secret) if the submitted values match the recorded values, said computer readable medium comprising: A. instructions for securely booting a computer, comprising: i. instructions for measuring data involved in a boot process; ii. instructions for submitting a measurement of said data to the HSM; iii. instructions for requesting release of the sealed secret from the HSM, wherein said instructions for securely booting a computer cannot successfully complete a normal boot operation without said secret; and iv. releasing the sealed secret only if the measurement submitted to the HSM is correct when compared to a recorded value, wherein the released sealed secret is different from the measurement and the recorded value; and B. instructions for updating said data involved in a boot process, comprising: i. instructions for migrating the released secret to temporary storage where it remains while the data involved in the boot process is updated; ii. instructions for measuring updated data involved in the boot process; and iii. instructions for restricting access to the migrated released secret by resealing it using the measurement of the updated data involved in the boot process, wherein the secret may be subsequently obtained by submitting at least a measurement of said updated data to the HSM.