Abstract: A wireless sensor network (WSN) is a network system for geographically distributed resources using wireless sensor nodes to observe physical or environmental conditions such as temperature, motion, and sound. The nodes are individually capable to send data to one or more collection points in a WSN to sense their environments and processing the information data locally. WSNs are great solutions for most applications and security is often a major concern. Though research regarding cryptography, secures routing, key management, intrusion detection, and secure data aggregation in WSNs is done until today, there are still some challenges to be addressed. These challenges are like first selection of proper cryptographic method second factors affecting sensors like memory, speed, and bandwidth, third challenge is, most of the available protocols assume that the sensor nodes and the base station are stationary. Sensor node and base stations in some situations like battlefield need to be mobile. The sensor network topology is been extensively affected by mobility of sensor nodes and so raises many issues about secure routing protocols. This paper surveys various security issues related to cluster based WSNs and existing security protocols.

Keywords: Cluster-based WSNs, ID based digital signature, Secure data transmission, wireless sensor networks, secure routing protocol.