Study Of Some Security Problems In Wireless Sensor Networks

Wireless Sensor Networks (WSN) have wide application. Due to the openness ofwireless communication and the limitation of sensor’s energy, storage and computation,the traditional security technologies, such as RSA, can not applied directly and securecommunication of WSN attracted much attention. This dissertation investigates someproblems of secure communication in WSN and obtains main results as follows:(1). Key distribution is one of the most challenging security problems in wireless sen-sor networks, existing approaches to this problem are key pre-distribution scheme(KPS). In most of existing KPSs, the sensor nodes may preloaded some uselesskeys which make no contribute to establish pairwise key between neighbor nodesand result certain security hole. Authors proposed a novel Useless Keys Eliminat-ing method based on location knowledge for wireless sensor networks. To illustratehow to eliminate the useless keys in network initialization, we applied our methodto a location-based key pre-distribution scheme (LBKP). Analysis and simulationshows that our method improved the key security efectively under node compromiseattack.(2). Broadcasting is an important method of communication in wireless sensor networkand the broadcast message should be authenticated in time. μT ESLA-based broad-cast authentication schemes are efcient due to using symmetric key, but delayed keydisclosure results some security threads. In signature-based authentication schemes,broadcast messages can be verifed in time, but the bogus messages are fltered byperforming expensive signature verifcation and the signature-based authenticationschemes are vulnerable to DoS (Denial of Service) attacks which aim at exhaustingthe node’s energy. Also, most of existing DoS-containment broadcast authentica-tion schemes are not suitable for multi-user wireless sensor networks. In this paper,authors proposed a multi-user broadcast authentication scheme in wireless sensornetworks with defending against DoS attacks(DDA-MBAS) based on vBNN-IBSsignature, the bogus messages can be fltered using hash operation and user in-formation. Compared with existing multi-user broadcast authentication schemes,except defending against node compromise attack and active attack, the bogus mes-sages can be fltered with low energy consumption and the threat of DoS attack andcollusion attack launched by compromised user can be limited efectively.(3). Author proposed a secure and transparent data aggregation scheme for wirelesssensor networks. Using homomorphic encryption, the aggregation node completed the data integrity checking, source identity authentication and data aggregationwithout decrypting the encrypted data, ensured the data privacy in the process oftransmitting and aggregation. Except providing high security of encrypt key, theproposed scheme had better performances in resilient against active attack, nodecompromise attack and DoS attack. Also, the results of data aggregation in theproposed scheme provide the information of the global data distribution.(4). Based on symmetric encryption and hash function, author proposed an efcien-t encrypted data aggregating method for wireless sensor network, the aggregatorscompleted the data integrity checking, source identity authentication and data ag-gregation via MAC (Message Authentication Code) verifcation and provided end-to-end security for data transmission. The proposed scheme makes better utilizationof high redundancy of neighbor sensors’ readings and reduces the communicationoverhead efectively.