The implementation of a standard PKI in a mobile ad hoc network (MANET) is not practical for several reasons: (1) lack of a fixed infrastructure; (2) a centralized certification authority (CA) represents a single point of failure in the network; (3) the relative locations and logical assignments of nodes vary in time; (4) nodes often have limited transmission and computational power, storage, and battery life. We propose a practical distributed CA-based PKI scheme for MANETs based on Elliptic Curve Cryptography (ECC) that overcomes these challenges. In this scheme, a relatively small number of mobile CA servers provide distributed service for the mobile nodes. The key elements of our approach include the use of threshold cryptography, clusterbased key management with mobile CA servers, and ECC. We show that the proposed scheme is resistant to a wide range of security attacks and can scale easily to networks of large size.
Charikleia Zouridaki, Brian L. Mark, Kris Gaj, Ros