Patent ID: 8925055

Claim:
A method by which the trustworthiness of a digital rights management (DRM) client on a device is established with a DRM server system, the device being one of a population of devices requiring validation as a condition to obtaining rights to play back digital content, the method including the steps, performed in a secure execution environment of the device distinct from a normal execution environment in which a content player executes content playback, of: securely loading loader code from secure programmable memory of the device and verifying the loader code by performing first digital signature calculations using a first manufacturer public key stored in the secure programmable memory; by the loader code upon being verified, loading DRM client code from the secure programmable memory and verifying the DRM client code by performing second digital signature calculations using a second manufacturer public key included in the loader code; and by the DRM client code upon being verified: obtaining a domain key from the secure programmable memory, the domain key being one of a set of distinct domain keys stored in the DRM server system for validating the devices, each domain key of the set shared by a respective sub-set of the devices; encrypting a unique device identifier for the device using the domain key; sending the encrypted device identifier along with a hash of the domain key to the DRM server system as part of a device registration message of a device registration process by which the device becomes registered with the DRM server system to receive the content licenses; and in response to receiving a registration response message sent by the DRM server system in response to the device registration message, (i) decrypting the registration response message using the domain key to obtain a device validation token, and (ii) subsequently using the device validation token in communications with the DRM server system to prove trustworthiness of the device for receiving the rights from the DRM server system to play back the digital content.