Multicast delivery scheme for threshold secret shared content

A threshold secret sharing scheme can deliver important content reliably using redundant delivery routes via a network. Furthermore, simultaneous delivery of the threshold secret shared content to multiple receivers can achieve efficient resource utilization thanks to multicast and network coding techniques. Nevertheless, the network coding technique results in a tradeoff between reliability and efficiency. This paper proposes a multicast delivery scheme for threshold secret shared content that can control the tradeoff between reliability and efficiency. In the proposed scheme, all the pieces obtained from the original content are grouped in advance, and network coding is only applied to the pieces included in the same group. This paper also proposes two kinds of heuristic multicast delivery route computation methods to optimize the proposed multicast delivery scheme in networks on a practical scale. The evaluation results show that the proposed scheme adopting an optimized number of groups can actually minimize the total link bandwidth required while satisfying the given requirement on content loss probability.