Efficient detection of public key infrastructure-based revoked keys in mobile ad hoc networks

Key revocation involves secure and efficient managing of the information about compromised keys. Spreading the information of revoked keys to the receivers of the key is a challenging task in public key infrastructure (PKI). PKI is more suitable for wired Internet infrastructure and lacks any tailor-made protocols for extension over an ad hoc network. The paper presents a Mobile Ad hoc Key Revocation Server (MAKeRS) scheme which proposes to improve the performance and reliability of the system. Simulation shows that the concept presented in the paper is more reliable, faster, and scalable than the existing usage of PKI over ad hoc networks. It proposes auto-creation of zone of network availability (ZoNA) by each MAKeRS, which holds the revocation list and is the best service provider in its zone. A node automatically updates the identity of the key revocation server when it enters a new ZoNA. Each node maintains a list of identities of the key revocation servers sorted in order of their communication overhead. This list is regularly updated based on the broadcast from the servers and also gets modified based on the mobility of nodes and servers. The various scenarios of mobility of nodes and servers are considered and the scheme is designed to suit such scenarios in an optimum way. It reduces the time to gain information about the revocation list and ensures availability and, thus, improvement of the system as a whole. Hence, the proposed system results in scalable, reliable, and faster PKI infrastructure and will be attractive for the mobile ad hoc network (MANET) users who frequently connect to the Internet for secured transactions. We discuss the architecture as well as the performance of our scheme compared to the popular existing scheme. However, our scheme does not call for the entire change in PKI, but is compatible with the existing scheme. Our simulations show that the proposed scheme is better for key revocation. Copyright (C) 2009 John Wiley & Sons, Ltd.