En-Route Filtering Techniques in Wireless Sensor Networks: A Survey

Majority of wireless sensor networks (WSNs) are deployed in unattended environments and thus sensor nodes can be compromised easily. A compromised sensor node can be used to send fake sensing reports to the sink. If undetected these reports can raise false alarms. To deal with the problem of fake report generation, a number of en-route filtering schemes have been proposed. Each of these schemes uses different cryptographic methods to check the authenticity of reports while they are being forwarded hop by hop toward base station. However, majority of these techniques can handle only limited compromised nodes or they either need node localization or statically configured routes for sending reports. Furthermore, majority of en-route filtering techniques are vulnerable to various denial of service attacks. Our main aims in this survey are: (a) to describe the major en-route filtering techniques, (b) to analyze these techniques on various parameters including security and (c) to outline main unresolved research challenges in en-route filtering in WSNs.