Topic-based Synchronization (TBS) Protocols to Prevent Illegal Information Flow in Peer-to-Peer Publish/Subscribe Systems

Abstract

In a peer-to-peer type of topic-based publish/subscribe (P2PPS) model, each peer (process) can publish an event message and receive an event message in which the peer is interested. Subscription of a peer and publication of an event message are specified in terms of topics. In the topic-based access control (TBAC) model proposed in our previous studies, only a peer granted publication and subscription rights is allowed to publish event messages with publication topics and to subscribe events, respectively. In our previous studies, the subscription-based synchronization (SBS) and subscription initialization SBS (SI-SBS) protocols are proposed where notifications which may cause illegal information flow are banned to prevent illegal information flow. It is checked whether or not an illegal information flow to occur in terms of subscription and publication rights granted to each peer. However, even some legal notifications are banned while no illegal event message is notified. In this paper, we newly propose a topic-based synchronization (TBS) and subscription initialization TBS (SI-TBS) protocols where only topics which each peer manipulates are considered. We show the number of notifications banned is reduced in the TBS and SI-TBS protocols compared with the SBS and SI-SBS protocols in the evaluation.