Trusted license removal in a content protection system or the like

摘要

A digital license includes an identification of a removal service that can authorize removing such license. A client selects the license to be removed and the service, constructs a challenge including therein a challenge license identification block (LIB) identifying the license to be removed, and sends the challenge to the service. The service receives the challenge, stores at least a portion of the challenge in a database, constructs a response corresponding to the challenge and including therein a response LIB identifying the license to be removed and an identification of the service, and sends the response to the client.; The client receives the response, employs the response LIB from the response to identify the license to be removed, and removes the identified license upon confirming that the identification of the service in the identified license matches the identification of the service in the response.