Patent ID: 8595505

Claim:
A non-transitory machine readable medium having instructions stored thereon that, when executed by a processor of a personal digital assistant or a cellular telephone, the instructions cause the respective personal digital assistant or cellular telephone to perform operations comprising: signing a message received from a verifier using a private signature key of the respective personal digital assistant or cellular telephone; transmitting a digitally signed message, including a group digital signature of the respective personal digital assistant or cellular telephone to the verifier, the verifier to authenticate the group digital signature to verify that the respective personal digital assistant or cellular telephone is a trusted member device of a trusted membership group by performing the following operations: performing a first verification that the respective personal digital assistant or cellular telephone remains a trusted member device of the trusted membership group according to a private member key component of the private signature key of the respective personal digital assistant or cellular telephone; performing a second verification that the anonymous hardware device remains a trusted member device of the trusted membership group according to a rogue key list of revoked member keys, wherein the second verification comprises a determination that the private member key component of the private signature key of the respective personal digital assistant or cellular telephone is cryptographically eliminated as a match to any one of the plurality of revoked member keys in the rogue key list; and wherein the first verification and the second verification are to be performed by the verifier without the verifier determining the private member key or any unique device identification information of the respective personal digital assistant or cellular telephone to enable the respective personal digital assistant or cellular telephone to remain anonymous to the verifier.