Lawrence Berkeley National Laboratory

The IEEE 802 standards ease the deployment of networking infrastructures and enable employers to access corporate networks while traveling. These standards provide two modes of communication called infrastructure and ad-hoc modes. A security solution for the IEEE 802.11's infrastructure mode took several years to reach maturity and firmware are still been upgraded, yet a solution for the ad-hoc mode needs to be specified. The present paper is a first attempt in this direction. It leverages the latest developments in the area of password-based authentication and (group) Diffie-Hellman key exchange to develop a provably-secure key-exchange protocol for IEEE 802.11's ad-hoc mode. The protocol allows users to securely join and leave the wireless group at time, accommodates either a single-shared password or pairwise-shared passwords among the group members, or at least with a central server; achieves security against dictionary attacks in the ideal-hash model (i.e. random-oracles). This is, to the best of our knowledge, the first such protocol to appear in the cryptographic literature.