This scheme is based on broadcast transmission and the sender only requires the position of its own and the destination. All active neighborhood nodes who receive the packet will go through the contention phase. Once the contention phase is complete, the winner (the node that is closest to the destination) will relay the packet using the same mechanism. selleck chemical Erlotinib This process will repeat until the destination becomes one-hop away. The authors assumed that all nodes in the neighborhood do not remain active all the time. Due to the dynamics of the sleep modes, different sets of potential relays will be available. However, mostly the potential route is close to the same or shortest route, which makes easier for an adversary to trace back to the sender.A. Capone et al. [10] proposed Simple Forwarding over Trajectory (SiFT) scheme.

This scheme is based on broadcast transmission and does not maintain neighborhood positions Inhibitors,Modulators,Libraries and states. Each node who receives the packet will make the decision of forwarding that packet based only on its own position, the position of a transmitter and the trajectory. The difference between the GeRaF [8, 9] and the SiFT scheme is that, the GeRaF does not use trajectories but the position of the destination. If nodes are static then similar to the GeRaF the potential route is close to the same or shortest route, which makes it easier for an adversary to trace back to the sender.A. D. Wood et al. [6] have proposed a configurable secure routing protocol family called Secure Implicit Geographic Forwarding (SIGF) for WSNs.

The SIGF is based on Inhibitors,Modulators,Libraries the Implicit Geographic Forwarding (IGF) protocol [11], in which a packet is forwarded to the node that lies within the region of 60�� sextant, centered on the direct line from the sender to the destination. The SIGF protocol provides some aspects of networks privacy such as data, route and location privacy, but it does not provide identity privacy. Another limitation of the SIGF protocol is that, when there is no trusted node within a forwarding area (assuming 60�� sextant), it will forward the packet to an un-trusted Inhibitors,Modulators,Libraries node. So, the reliability of the path is affected.Table 1 compares the proposed privacy preserving schemes. It clearly shows that none of the schemes currently provide full network Inhibitors,Modulators,Libraries level privacy.Table 1.Comparison of privacy preserving schemes.3.?Network, Assumptions and Adversary Model3.

1. Network ModelA wireless sensor network (WSN) is composed of large number of small sensor nodes that are of limited resource and densely deployed in an environment. Whenever end users require information about any event related to some object(s), they Batimastat send a query to the sensor network via the base station. And the base station propagates that query to the entire network or to a specific region of the network. In response to that query, sensor nodes send back required sellectchem information to the base station. A typical wireless sensor network scenario is shown in Figure 1.