Patent ID: 7757085

Claim:
A method for enabling a set of transmitters and receivers to implement a content protection protocol, said method including the steps of: (a) determining combinations of key selection vectors and private key sets such that each of the private key sets together with one of the key selection vectors and a predetermined algorithm determines a shared secret, such that the key selection vectors belong to a full vector set consisting of a first subset of the key selection vectors and a second subset of the key selection vectors, and the first subset of the key selection vectors excludes a sufficient number of the key selection vectors of the full vector set to prevent determination, by reverse-engineering, of the shared secret from only the private key sets and said first subset; and (b) distributing one of the key selection vectors in the first subset and one of the private key sets to each of the transmitters and receivers while reserving the key selection vectors of the second subset so that none of the key selection vectors in the second subset is distributed to any of the transmitters or any of the receivers.