Abstract: A long-lived broadcast encryption method that adapts to the presence of compromised keys and continues to broadcast securely to privileged sets of users over time. In one aspect, a method for providing long-lived broadcast encryption comprises the steps of: allocating, to each of a plurality of subscribers, a corresponding set of subscriber keys; broadcasting encrypted content to the plurality of subscribers using a set of broadcast keys, wherein the encrypted content is decoded by a given subscriber using the subscriber's corresponding set of subscriber keys; modifying the set of broadcast keys, which are used for broadcasting encrypted content, by excluding compromised subscriber keys; and updating a set of subscriber keys corresponding to at least one subscriber when the at least one subscriber's set of subscriber keys comprises an amount of active keys that falls below a first predetermined threshold.

Abstract: Given the recent changes in the policy governing Internet content distribution, such as the institution of per listener royalties for Internet radio broadcasters, content distributors now have an incentive to under-report the size of their audience. Previous audience measurement schemes only protect against inflation of audience size. We present the first protocols for audience measurement that protect against both inflation and deflation attempts by content distributors. The protocols trade-off the amount of additional information the service providers must distribute to facilitate audience inference with the amount of infrastructure required and are applicable to Internet radio, web plagiarism, and software license enforcement. The protocols can be applied to other situations, such as auditing website screen scrapers and per-seat licensed software installations.

Abstract: Given the recent changes in the policy governing Internet content distribution, such as the institution of per listener royalties for Internet radio broadcasters, content distributors now have an incentive to under-report the size of their audience. Previous audience measurement schemes only protect against inflation of audience size. We present the first protocols for audience measurement that protect against both inflation and deflation attempts by content distributors. The protocols trade-off the amount of additional information the service providers must distribute to facilitate audience inference with the amount of infrastructure required and are applicable to Internet radio, web plagiarism, and software license enforcement. The protocols can be applied to other situations, such as auditing website screen scrapers and per-seat licensed software installations.

Abstract: Systems and methods that allow the formation and distribution of session keys amongst a dynamic group of users communicating over an unreliable, or lossy, network.