LISISAP: link level signature based secure anonymous protocol for prevention of traffic analysis attacks

For any communication (wired or wireless) such as control and data, the identity of source and destination is revealed in the header portion of the packet. Adversaries obtain sensitive in-formation such as the identity, location of a critical node, route, data, etc., during communication by using traffic analysis at-tacks, viz., similarity attack, data integrity attack, packet count-ing attack, latency attack, and clogging attack. Anonymous communication prevents adversaries from doing traffic analysis against the routing information embedded in the routing mes-sages and data packets. In order to thwart such traffic analysis, anonymous communication protocols were developed. In this paper, the existing anonymous communication protocols were analyzed in terms of techniques used, challenges, and applications. Anonymous Routing protocol with Multiple Routes (ARMR) is one of the existing protocols that achieves better route anonymity using fake routes and multiple paths. However, in ARMR, adversaries can modify the data with genuine user pseudonyms and send the modified data to the destination. In order to prevent data modification by adversary at link level, in this paper a Link level SIgnature based Secure Anonymous Protocol (LISISAP) protocol is proposed. In LISISAP, source node generates a signature for the data and sends the signature along with the encrypted data to the next node. Further, the next node verifies the signature. If signature matches, it generates its own signature and sends the encrypted data to its next node. Otherwise, it discards the packet. Verified data and signature are sent by each intermediate node until it reaches the destina-tion. In LISISAP, even if adversaries modify the data, every node in the route including the destination node verifies the data and discards the data if there is no match in the signature. Similarity attacks can be prevented by making the data look different on each hop which could be achieved by encrypting the data with link key. Proposed protocol, LISISAP is imple-mented and tested in Smart and Secure Network. From the ex-perimental results, it is evident that the data generated by source node is sent anonymously to the destination. Thus, in LISISAP protocol, communication is secure between nodes without revealing the node identities. Anonymous properties such as identity privacy, location privacy, route anonymity, and robustness against several attacks were achieved.