Users of wireless sensor networks face difficulties like key distribution. Also there is a large number of keys saved in them. Thus, they tended to use public key cryptography for identification and key agreement. On the other hand, certificate-based public key cryptography makes use of public key infrastructure (PKI). Clearly implementing PKI requires a large amount of memory computations and communications which are impassible for sensor networks. To solve this problem we can use identity based cryptography (IBC). In this type of cryptography, user’s public identities like their IP or email addresses are used as their public key as a result, there will be no need for PKI. After introduction of pairing based cryptography, this type of cryptography was applicable used. In this paper, we will take a look at how to use pairings on wireless sensor networks.

Wireless Sensor Networks (WSNs) are an ideal solution for miscellaneous applications of surveillance and control, such as traffic control, environmental monitoring, and battlefield surveillance. The wireless sensor nodes have limited memory and processing capability. The Sybil Attack is a serious threat in which a malicious node creates multiple fake identities in order to mislead the other sensor nodes. This attack can have influence on routing protocols and the operations like voting and data aggregation. In this paper, we present a dynamic and lightweight algorithm with a confidence-aware trust approach. The Algorithm uses the trust value of each sensor node to reduce the false alarm rates and detect indirect Sybil attacks in WSNs. The simulation results demonstrate that the average detection and wrong detection rates are 92% and 0.08% respectively.