Key Management in Mobile Ad Hoc Networks

Mobile ad hoc networks (MANETs) eliminate the need for pre-existing infrastructure by relying on the nodes to perform all network services. The connectivity between the nodes is sporadic due to the shared, error-prone wireless medium and frequent route failures caused by node mobility. Fully self-organized MANETs are created solely by the end-users for a common purpose in an ad hoc fashion. Forming peer-to-peer security associations in MANETs is more challenging than in conventional networks due to the lack of central authority. This thesis is mainly concerned with peer-to-peer key management in fully self-organized MANETs. A key management protocol’s primary function is to bootstrap and maintain the security associations in the network, hence to create, distribute and revocate (symmetric or asymmetric) keying material as needed by the network security services. The fully self-organized feature means that the key management protocol cannot rely on any form of off-line or on-line trusted third party (TTP). The first part of the thesis gives an introduction to MANETs and highlights MANETs’ main characteristics and applications. The thesis follows with an overall perspective on the security issues in MANETs and motivates the importance of solving the key management problem in MANETs. The second part gives a comprehensive survey on the existing key management protocols in MANETs. The protocols are subdivided into groups based on their main characteristic or design strategy. Discussion and comments are provided on the strategy of each group. The discussions give insight into the state of the art and show researchers the way forward.