Trustworthy Routing with the TORA Protocol

Ad-hoc networks are made up of one or more low power mobile wireless nodes. These nodes are able to communicate over a wide range through mutual cooperation. All participating nodes pledge to pass packets for other nodes in accordance to a pre-agreed protocol. Temporally Ordered Routing Algorithm (TORA) is one of the unique routing protocols that can operate in dual mode (passive or active) based upon the mobility of the network. In TORA, heights are assigned to nodes so as to route the flow of data according to a directed acyclic graph. Routes are established in TORA with the assistance of other nodes present in the network. The accuracy of these routes requires that all network nodes depict benevolent behaviour. However, such an altruistic setting is virtually impossible to achieve and consequently a number of malicious nodes also contribute to the TORA route discovery process only to impair the network. In this paper we present a novel and pragmatic mechanism for establishing trust in ad-hoc networks that execute the TORA protocol for route discovery. The proposed mechanism is especially viable for ad-hoc networks that can be created on the fly without a formal trust infrastructure including Certification Authorities and Key Distribution Systems.