Attackers can easily capture and rework sensor nodes as malicious nodes. Routing protocols of sensor networks are insecure and highly vulnerable to malicious node attacks. In order to protect network against malicious attackers, routing protocols have been developed to improve network performance with the help of cryptographic techniques. But, requirements of such secure routing protocols include configuration of the nodes with encryption keys and the creation of a centralized or distributed key repository.
The Greedy Perimeter Stateless Routing is one of the commonly used location-based routing protocols for establishing and maintaining a sensor network. This protocol virtually operates in a stateless manner and has the ability for multi-path routing. In GPSR, it is assumed that all nodes recognize the geographical position of destination node with which communication is desired. This location information is also used to route traffic to its requisite destination from the source node through the shortest path.
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https://www.researchgate.net/publication/45825694_Secured_Greedy_Perimeter_Stateless_Routing_For_Wireless_Sensor_Networks