Half-Broadcast Encryption for Anonymity

Broadcast Encryption(BE) have been widely used to pay TV, distributed systems and others. In general concept of this encryption, most BE schemes have to broadcast all packets to all network because of intermediate nodes cannot know accurate nodes needing broadcasted packets due to encryption. In this paper, we propose Half-Broadcast Encryption(HBE). Recently, a number of distributed systems have been designed as hierarchical model composed of several levels. In the model, HBE communicates as top-down with reducing logwgbn traffic than general broadcast encryption. In the proposed scheme, intermediate nodes decides whether they broadcast received packets with protecting anonymity of destinations. For the reason, HBE can reduce the packets over the network to more than half due to flexible broadcasting without any identity of destination.