Research On The Key Management Based On Asymmetric Cryptography For Wireless Sensor Networks

With the high speed and widespread development of WSNs, its security issues have drawn intensive attention from both the academia and industry society.In the research area of WSN security, key management is a key technique for providing security for communication and routing in WSNs. Among various key management schemes, the scheme based on symmetric cryptography is most popular. However, this method cannot meet the high requirement in military applications. On the other hand, recently the asymmetric key management schemes have been shown to be applicable in sensor nodes and can satisfy the high security requirement of the WSNs. Due to this reason, in this thesis we focus on studying and designing a suitable key management scheme based on asymmetric cryptography for WSNs.The main work of this thesis is as follows:1. This thesis provides a review of the study of WSNs, and then introduces and analyzes some classical key management schemes, with an emphasize on the elliptic curve cryptography algorithm and the identity-based algorithm.2. Based on the summarized advantages and disadvantages of the existing schemes, this thesis proposes an efficient identity-based key management scheme. This scheme can not only achieve the legality verification of the public key, but also avoid the complex certification process through the Certification Center. Moreover, this scheme can save plenty of storage space by employing the Bloom filter technique. Also, this scheme utilizes the identity-based cryptographic technique to achieve key agreement, which improves the safety of key distribution process while saving the computation and communication overhead.3. Then This thesis proposes a new elliptic-curve-based key management scheme based on the LEACH protocol. This scheme adopts the Elliptic Curve Paillier Encryption (ECPE) method, in combination with the AVL tree for the ID and public key storing. This scheme can achieve higher security at the cost of much less keys, reduce the search time, improve the system efficiency and reduce the energy consumption. In addition, our scheme is more scalable, i.e., all nodes are allowed to be added in or deleted. With regular key updates, the security of the network can be additionally improved.4. We evaluate our schemes in memory, computation and communication overhead, and also make a comparison with existing schemes.