Detection Of Malicious Node And Secure Routing Technique In Wireless Sensor Networks

Wireless sensor networks(WSN) is a new electronic technology which is a fusion of communication, embedded system, sensors and other disciplines, and it has a wide application prospect. WSN is composed of a set of sensor nodes which has the features of self-organization, multiple-hop and limited energy resources, etc. Nowadays, the main researching contents of WSN include network topology, node routing algorithm, wireless communication protocol and security defense technology.WSN is the most widespread application in military field, so its security problem is the research hotspot in this field. In this thesis, the security defense technology of WSN is lucubrated. The attack types to WSN include insider attack and outsider attack: the traditional encryption technology can only resist outsider attacks; after normal nodes captured and cracked by the attacker, it is hard to defense the insider attacks from malicious nodes. In this thesis, after analyzing the characteristics of various network attacks, the research of selective forwarding attack which is the most difficult in the insider attack is focused on. And a security routing mechanism which can resist various attacks was designed. The full text work is as follows:1. Through summarizing the existing research results, the security mechanism against the internal attacks should have the following features: firstly, it can detect the malicious nodes accurately and quickly and ensure the attack mode; secondly, it can feedback information in real time and update the routing; thirdly, it should have lightweight complexity and low energy consumption; fourthly, it can solve a variety of attacks instead of the single attack. In this thesis, the security mechanism was designed based on the conclusion above.2. A secure routing protocol based on monitor mode and trust mechanism is proposed from the analysis of watchdog, trust, neighbor nodes monitoring and other detection mechanisms. The network model, realized the topology, designed node working mode and the packet structure were built by OPNET network simulation software. At last, the whole process of network data forwarding and safety inspection were simulated.3. Trust model was established in this thesis. Through listening the process of ordinary nodes’ data sending and receiving, monitoring nodes calculate the creditworthiness of each node and decide whether their behaviors are abnormal. The trust value and residual energy of nodes are used to make the choice of routing nodes. Moreover, the adaptive threshold changing with channel environment is used as the detection threshold and the mathematical proof was provided in this thesis.4. Simulation results indicate that: firstly, the detection of malicious nodes can be realized by our security mechanism; secondly, according to the situation, the weights of trust value can be changed to meet the requirements of different networks; thirdly, compared with the watchdog and neighbor node monitoring mechanism, the false detection rate of our security mechanism is only about 3%, 14%-25% lower than the first two.