Thwarting Attackers in the Wireless Networks without Trusted Authorities

Due to the broadcast nature of the wireless medium, wireless networks are especially vulnerable to Sybil attacks, where a malicious node illegitimately claims a large number of identities and thus depletes system resources. A wireless sensor network consists of many sensor nodes which are deployed to monitor physical or environmental conditions and to pass the collected data to a base station. Though wireless sensor network is subjected to have major applications in all the areas, it also has many security threats and attacks. Among all threats such as sinkhole, wormhole, selective forwarding, denial of service and node replication, Sybil attack is a major attack where a single node has multiple identities. When a Sybil node acts as a sender, it can send false data to its neighbors. When it acts as receiver, it can receive the data which is originally destined for a legitimate node. Further, we note that prior signal print methods are easily defeated by mobile attackers and develop an appropriate challenge-response defense. Finally, we present the Mason test, the first implementation of these techniques for ad hoc and delay-tolerant networks. A message can be sent to the receiver directly without trusted authorities.