Research On Resilient Key Establishment Protocols In Wireless Sensor Networks

Wireless sensor networks which comprise the technologies of microelectronics, sensoring and communications can be widely applied to the fields of education, military, medicine, transportation, environment monitoring and so on, attracting quite a lot of researches on it. Security is one of the most basic tasks in wireless sensor networks especially for the case that sensors are distributed in the unprotected environments occasionally suffering from node capture attacks. Key management in wireless sensor networks in pursuit of secure and reliable communications is the kernel of other kinds of services in WSNs such as secure routing, secure location and secure data aggregation.Key establishment in wireless sensor networks can be categorized into pairwise key establishment, path key establishment and group key establishment. Pairwise key establishment is defined to the case that each pair of neibouring nodes can establish directly shared keys according to the predistributed information. Path key establishment refers to the scenario that each pair of sensor nodes not possessing the shared keys can establish a secure key in the help of the intermediate nodes possessing the shared keys between them. Group key establishment is explained as the situation that all the sensors negotiate a shared communication key.This thesis mainly focuses on the following topics: distributed key management in wireless sensor networks, pairwise key establishment resistant to mobile attacks, self-healing key distribution with multi-level revocation capacity and path key establishment based on secure routing. The main contributions are made as follows. 1. In the scheme of distributed key management in WSNs, the concept of seed members responsible for dynamically join and revocation was derived. In addition, a novel seed member alternation mechanism which can efficiently resist of node capture attacks leaves the recouces much more balanced between sensor nodes to prolong the lifetime of WSNs. Finally, the key continuity enable all the sensors to establish and update both of the pairwise keys and the group keys with the same predistributed information, which significantly decreases the resource consuming of key management in distributed sensor networks.2. A novel cluster based pairwise key establishment scheme is proposed. In this scheme, cluster heads distribute key materials at the requests of their own members and allow sensor nodes in different clusters to communicate with each other interactively by establishing pairwise keys inter-clusterly. Besides, an improved scheme based on proactive secret sharing is devised to resist of mobile attacks and deal with the situations of dynamically joining and leaving, realizing increased network connectivity and resilience to mobile attacks in whatever respectives of time or space.3. An efficient self-healing key distribution scheme with multi-level revocation capacity is proposed in this paper by using a resilient polynomial and an improved Huang's secret sharing scheme. This scheme can resist to the attack sponsored by the collaboration of joining and revoked members. Besides, the round of this scheme is free of the fixed trapdoor, making it with a long life span. Finally, personal keys can be selected by the users individually and the establishment of secure channel can be avoided, addressing the problem of dynamic joining. It also realizes the mutual authentication between the users and the group manager and achieves the efficient tradeoff between security and performance by decreasing the storage overhead of users to a constant and the communication overhead to a much lower level.Finally, the Visual C++ compiled language is utilized to realize the system of these schemes mentioned above. The results of experiments show that the analysis of the resilient key establishment protocols is true and these proposed schemes are feasible and efficient in practice.