On Notification Message Re-broadcasting for the Node-Disjoint Multipath Routing Method in Ad Hoc Networks to Counter Eavesdropping of Data Packets

Ad hoc networks are autonomous distributed networks which consist of wireless terminals (referred to as "nodes"). In ad hoc networks, transferred data packets can be stolen by malicious relaying nodes and can be eavesdropped on by malicious nodes on paths within the broadcast range. To counter the stealing of transferred data packets, the secret sharing scheme-based secure dispersed data transfer method has been proposed [1][2][3]. In this method, multiple encrypted data (referred to as "shares") are created from the original data. The original data can be decrypted by collecting more than the pre-determined threshold number of shares. To avoid decryption using stolen transferred shares, the routing ID-based node-disjoint multipath scheme for ad hoc networks has been proposed [4][5][6]. This method selects the three shortest of available node-disjoint multiple paths and transmits data packets along the paths. In this method, however, since the broadcast range of the paths can overlap, malicious eavesdropping nodes can decrypt the original data. Therefore, it is necessary to reduce the overlap of node-disjoint multiple paths in the broadcast area. In this paper, we propose a new node-disjoint multipath routing method to counter the eavesdropping of data packets. In our proposed method, the paths are constructed to attempt to prevent the overlap of broadcast areas. By reducing the overlap, our proposed method attempts to prevent the eavesdropping of shares. We have implemented our proposed method on a simulator, and have conducted experiments in terms of both the data packet delivery ratio and the confidentiality of transferred data packets. We have confirmed that the number of eavesdropped data packets in our proposed method is smaller than that in the existing method.