Efficient and Self-Healing Key Distribution with Revocation for Tactical Wireless Networks

This paper presents group key distribution techniques for highly mobile, volatile and hostile wireless networks in tactical situations (e.g., anti-terrorist operations, battle fields). The techniques proposed here are based on the self-healing key distribution methods (with revocation capability) recently developed by Staddon et al. By introducing a novel personal key distribution technique, this paper reduces (1) the communication overhead of personal key share distribution from $O(t^2\log q)$ to $O(t\log q)$, (2) the communication overhead of self-healing key distribution with $t$-revocation capability from $O((mt^2+tm)\log q)$ to $O(mt\log q)$, and (3) the storage overhead of the self-healing key distribution with $t$-revocation capability at each group member from $O(m^2\log q)$ to $O(m\log q)$, where $t$ is the maximum number of colluding group members, $m$ is the number of sessions, and $q$ is a prime number that is large enough to accommodate a cryptographic key. All these results are achieved without sacrificing the unconditional security of key distribution. In addition, this paper presents two techniques that allow to trade off the broadcast size with the recoverability of lost session keys. These two methods further reduce the broadcast message size in situations where there are frequent but short-term disruptions of communication and where there are long-term but infrequent disruptions of communication, respectively.