Several Security Issues In Wireless Sensor Networks

Wireless Sensor Networks has a wide application, but the security is still an important issue. We extend our work on several hot security-related topics in Wireless Sensor Networks.The first part of our work focuses on building up a trust system in Wireless Sensor Networks to enhance its security. Our trust system is different from traditional trust systems. We suggested a new term "certainty" used in trust system to build trust rating because there is unreliability and uncertainty in Wireless Sensor Networks. We discuss some important properties of evidence space, certainty and trust-rating, and we build up a model to calculate and distribute the trust-rating in Wireless Sensor Networks. Finally, we build a new trust model which based on event. In the new model, a node has several trust-rating which based on different event. The new model is different from the based trust model. A node has one trust rating in the based system model. Our new model can enhance the security, prolong the lifetime of nodes and improve the collaboration in Wireless Sensor Networks. The contribution of this work is suggested a new term "certainty" based on incomplete evidence space, and we use the certainty to build up trust rating to enhance the security in Wireless Sensor Networks. We also propose an event-based trust model to improve the performance of networks.The second part of our work is concerning DoS attacks in Wireless Sensor Networks. We propose a generic intrusion detection scheme for these attacks. In our scheme, there are monitor nodes and sensor nodes in Wireless Sensor Networks, the monitor nodes are listenning the channel then get the behavior data of sensor nodes and the state of the networks. At first, the monitor node use Pre-defined rules to check these data. If the monitor nodes find any data fail in any rules then to alarm and discard the data. If all the rules has been used and there is still data left, then the monitor nodes use key feature to check the left data and to find intrusion. When all the features has been used and still data left then the monitor node collect more data to check. The main contribution in this work is that we propose a generic intrusion detection scheme to detect all kinds of DoS attacks. Our scheme not only can detect some known attacks fast in Wirless Sensor Networks but also potentially applicable to detect some unknown attacks in Wireless Sensor Networks.The third part of our work is concerned with session key management in Wireless Sensor Networks. Due to the resource constraints, key management has been a quite challenging problem in Wireless Sensor Networks. We propose a new kind of message-based session key management schemes. In our scheme, only the direct neighbor node need to build session keys due to there is immediate communication, and our scheme can reduce the storage space for session keys.The process of exchanging message goes with updating session keys, and reduces the overhead of updating session keys on communication. By using dynamic updating session keys, the encryption and decryption keys are different every time while deal with the communication message. Our scheme can effectively prevent Physical attacks and Eavesdropping to enhance the security resilience. Our main contribution in this work focuses on the dynamic updating the session keys in resource constrainted sensor nodes to enhance the networks security...