ABSTRACT

Contents 6.1 Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 6.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 6.3 Issues of Key Management in WSNs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 6.4 Key Management Schemes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 6.5 Key Predistribution Schemes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

6.5.1 Basic Random KPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 6.5.2 Shared-Key Threshold R-KPS: The q-Composite R-KPS . . . . 121 6.5.3 Location-Aware R-KPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

6.5.3.1 Location-Aware R-KPS: Liu and Ning’s Scheme . . . 122 6.5.3.2 Location-Aware R-KPS: Group-Based Scheme . . . . 124 6.5.3.3 Location-Aware R-KPS: Grid Group-Based

Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 6.5.4 Pair-Wise Key Predistribution Schemes

with Structured Key Pool . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 6.5.4.1 Deterministic versus Nondeterministic

Pair-Wise KPS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127 6.5.4.2 Deterministic Pair-Wise KPS: Blom’s Scheme . . . . . 127 6.5.4.3 Deterministic Pair-Wise KPS: Blundo’s Scheme . . . 128

6.5.4.4 Nondeterministic Pair-Wise KPS: Du et al.’s Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129

6.5.4.5 Nondeterministic Pair-Wise KPS: Liu and Ning’s Scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

6.5.4.6 Combinatorial-Based R-KPS . . . . . . . . . . . . . . . . . . . . . . . . 133 6.5.5 Path-Key Establishment Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 6.5.6 Improved Shared-Key Discovery Schemes . . . . . . . . . . . . . . . . . 136

6.6 Some Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138 6.7 Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140

6.1 Abstract Key management plays a very important role in establishing secure communications in wireless sensor networks (WSNs). This chapter presents a comphrehensive overview of the current state-of-the-art of key management for sensor networks: key distribution schemes, key agreement schemes, and key predistribution schemes (KPS). Our focus is on KPS, which may be the only feasible key management method for WSNs. The following aspects of KPS schemes are discussed: (1) shared key threshold KPS; (2) location-aware KPS; (3) pairwise key predistribution scheme with structured keypool; (4) path-key establishment KPS; (5) improved shared-key discovery KPSs, and their performance is evaluated. The chapter also discusses some open research issues in this area.