Patent ID: 7711960

Claim:
A method for controlling access to a cryptographic key, the method comprising: receiving a configuration of a computing platform, the configuration comprising Platform Configuration Register (PCR) values of a Trusted Platform Module (TPM) of the computing platform; receiving the cryptographic key; receiving authorization data for accessing the cryptographic key; creating an authorization blob, the authorization blob locking the authorization data to the PCR values of the configuration, locking the cryptographic key to the authorization data, wherein the cryptographic key is stored outside of the authorization blob and the cryptographic key is a TPM key; deleting another authorization blob locking the authorization data to a measurement of another configuration of the computing platform; hashing one or more authorization blobs locking the authorization data to one or more configurations of the computing platform after the creating, the one or more hashed authorization blobs including the authorization blob and not including the deleted authorization blob, thereby creating a first hash; storing the first hash; booting the computing platform after the deleting; hashing one or more currently loaded authorization blobs locking the authorization data to one or more configurations of the computing platform, thereby creating a second hash, wherein the one or more currently loaded authorization blobs are currently loaded after the booting; comparing the first hash and the second hash; and accessing the cryptographic key, based upon a determination that the first hash matches the second hash.