Information Security and Privacy

Multi-service oriented broadcast encryption is a mechanism that allows a center to securely distribute multiple services to its authorized users. In this paper, we suggest a framework called M framework from the subset cover method [12] using RSA exponentiation technique. In this framework, each user’s secret storage is independent of the number of services. Service subscriptions and service providing can be efficiently processed. The service unsubscriptions are dealt scalably. A small number of service unsubscriptions can be handled without key updating while the number of such users reaches a threshold, a rekeying algorithm is proposed to update the user’s service memberships explicitly. We formalize and prove the framework is dynamically secure under the random oracle model. We realize our framework with a scheme based on complete subtree method.