Key management for multicast fingerprinting

Abstract

A secure multicast system allows a sender to send a message over a multicast channel to a dynamically changing group of users. A group key management solution, efficiently accommodating dynamic membership, is desirable. Fingerprinting technique has also been employed to trace traitors who illegally retransmit decrypted content to other unauthorized receivers. But, it makes key management much more challengeable. This paper studies this scenario, advances a notion of "subgroup key management", and indicates it should be collusion-free. Moreover, this paper also studies a general subset notion and employs It in subgroup key management approach. Especially, our dynamic key assignment scheme is a generalized mode of Logical Key Hierarchy (LKH), At same time, both symmetric and asymmetric cryptographic approaches for the subgroup key distribution are studied, Our approach can not only handle highly dynamic membership of a multicast session but also own very low overhead of communication, and it is collusion-free. Finally, the paper proves the security of proposed solutions and compares its efficiencies. © Springer-Verlag Berlin Heidelberg 2005.