Location dependent key management schemes supported by random selected cell reporters in wireless sensor networks

Abstract

In order to secure vital and critical information inside Wireless Sensor Net- works (WSNs), a security requirement of data con dentiality, authenticity and availability should be guaranteed. The leading key management schemes are those that employ location information to generate security credentials. Therefore, this thesis proposes three novel location-dependent key manage- ment schemes. First, a novel Location-Dependent Key Management Protocol for a Single Base Station (LKMP-SBS) is presented. As a location-dependent scheme, the WSN zone is divided virtually into cells. Then, any event report generated by each particular cell is signed by a new type of endorsement called a cell- reporter signature, where cell-reporters are de ned as a set of nodes selected randomly by the BS out of the nodes located within the particular cell. This system is analysed and proved to outperform other schemes in terms of data security requirements. Regarding the data con dentiality, for three values of z (1,2,3) the improvement is 95%, 90% and 85% respectively when 1000 nodes are compromised. Furthermore, in terms of data authenticity an enhancement of 49%, 24%, 12.5% is gained using our approach with z = 1; 2; 3 respectively when half of all nodes are compromised. Finally, the optimum number of cell reporters is extensively investigated related to the security requirements, it is proven to be z = n 2 . The second contribution is the design of a novel Location-Dependent Key Man- agement Protocol for Multiple Base Stations (LKMP-MBS). In this scheme, di erent strategies of handling the WSN by multiple BSs is investigated. Ac- cordingly, the optimality of the scheme is analysed in terms of the number of cell reporters. Both data con dentiality and authenticity have been proven to be / e / 1 N . The optimum number of cell reporters had been calculated as zopt = n 2M , PM `=1 jz(`) optj = n 2M . Moreover, the security robustness of this scheme is analysed and proved to outperform relevant schemes in terms of data con- dentiality and authenticity. Furthermore, in comparison with LKMP-SBS, the adoption of multiple base stations is shown to be signi cantly important in improving the overall system security. The third contribution is the design of the novel Mobility- Enabled, Location- dependant Key Managment Protocol for Multiple BSs (MELKMP-MBS). This scheme presents a key management scheme, which is capable of serving a WSN with mobile nodes. Several types of handover are presented in order to main- tain the mobile node service availability during its movement between two zones in the network. Accordingly, the communication overhead of MELKMP- MBS is analysed, simulated and compared with the overhead of other schemes. Results show a signi cant improvement over other schemes in terms of han- dover e ciency and communication over head. Furthermore, the optimality of WSN design such as the value of N; n is investigated in terms of communi- cation overhead in all protocols and it is shown that the optimum number of nodes in each cell, which cause the minimum communication overhead in the network , is n = 3 p 2N.