User Revocation in Secure Adhoc Networks

We focus on the problem of user revocation in secure adhoc networks. The current approach to achieve security in adhoc networks is to use a secret instantiation protocol in which, each user is given a subset of secrets from a common secret pool. To communicate securely, a pair of users use the secrets that are common to both of them. However, when users are compromised, some of these secrets are also compromised. Hence, to revoke the compromised users, the secrets known to these users need to be updated. Many group key management solutions exist for revocation of users from a group. However, due to the limitations in adhoc networks, i.e., lack of efficient broadcast mechanisms and lossy links, revocation of users is a challenging problem. In this paper, we propose a revocation algorithm that combines the secret instantiation protocols with group key management protocols. Depending on the combination of protocols used, our revocation algorithm provides deterministic or probabilistic guarantees for revocation. We illustrate our revocation algorithm by combining the square grid protocol and the logical key hierarchy protocol. Keywords: Secure Adhoc Networks, User Revocation, Secret Instantiation Protocols, Group Key Management Protocols.