Patent ID: 8341393

Claim:
A method comprising: prior to loading an operating system and prior to commencing a dynamic root of trust measurement session, creating one or more hashes, each hash associated with core root of trust measurement code, system management code, or core root of trust measurement code and system management code; prior to loading the operating system and prior to commencing the dynamic root of trust measurement session, storing the one or more hashes in one or more secure registers; prior to commencing the dynamic root of trust measurement session, loading the operating system; after loading the operating system and prior to commencing the dynamic root of trust measurement session, validating one or more certificates, each certificate associated with the core root of trust measurement code, the system management code, or the core root of trust measurement code and the system management code; after loading the operating system and prior to commencing the dynamic root of trust measurement session, responsive to the validation of the one or more certificates, providing one or more expected hashes, each expected hash associated with the core root of trust measurement code, the system management code, or the core root of trust measurement code and the system management code; after loading the operating system and prior to commencing the dynamic root of trust measurement session, based on successfully matching each of the one or more expected hashes to a corresponding one of the one or more stored hashes, commencing the dynamic root of trust measurement session; after commencing the dynamic root of trust measurement session, updating the core root of trust measurement code, the system management code, or the core root of trust measurement code and the system management code; altering one or more of the one or more stored hashes; entering a sleep state; resuming from the sleep state; and preventing execution of a loaded hypervisor based on the alteration of the one or more of the one or more stored hashes.