Multilayer multicast key management with threshold cryptography
Scott Dexter, Roman Belostotskiy, Ahmet M. Eskicioğlu · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2004
The problem of distributing multimedia securely over the Internet is often viewed as an instance of secure multicast communication, in which multicast messages are protected by a group key shared among the group of clients. One important class of key management schemes makes use of a hierarchical key distribution tree. Constructing a hierarchical tree based on secret shares rather than keys yields a scheme that is both more flexible and provably secure. Both the key-based and share-based hierarchical key distribution tree techniques are designed for managing keys for a single data stream. Recent work shows how redundancies that arise when this scheme is extended to multi-stream (e.g. scalable video) applications may be exploited in the key-based system by viewing the set of clients as a “multi-group”. In this paper, we present results from an adaptation of a multi-group key management scheme using threshold cryptography. We describe how the multi-group scheme is adapted to work with secret shares, and compare this scheme with a naïve multi-stream key-management solution by measuring performance across several critical parameters, including tree degree, multi-group size, and number of shares stored at each node.