Provably secure hybrid key agreement protocols in cluster-based wireless ad hoc networks

Wireless ad hoc networks support rapid on-demand and adaptive communication among the nodes due to their self-configurable and autonomous nature and lack of fixed infrastructure. Security is a crucial factor for such systems. Since ad hoc networks rely on the collaboration principle, the issue of key distribution and efficient group key management in such networks represents two of the most important problems. We describe hybrid solutions to the problem of key distribution and key management by reflecting ad hoc networks in a topology composed of a set of clusters. To date no security proofs exist for these types of protocols. We present two dynamically efficient schemes. We show that both our hybrid schemes are provably secure in the standard model under Decision Diffie–Hellman (DDH) assumption. The proposed protocols avoid the use of a trusted third party (TTP) or a central authority, eliminating a single point of attack. We analyse the complexity of the schemes and differentiate between the two approaches based on performance in a wireless setting. In comparison with the existing cluster-based hybrid key agreement protocols, our proposed approaches individually provide better performance in terms of both communication and computation, handle dynamic events efficiently, and are supported by sound security analysis in formal security models under standard cryptographic assumptions.