Unbalancing Pairing-Free Identity-Based Authenticated Key Exchange Protocols for Disaster Scenarios

In disaster scenarios, such as an area after a terrorist attack, security is a significant problem since communications involve information for the rescue officers, such as polices, militaries, emergency medical technicians, and the survivors. Such information is critically important for the rescue organizations; and protecting the privacy of the survivors is required. Normally, authenticated key exchange (AKE) is an underlying approach for security. However, available AKE protocols are either inconvenient or infeasible in disaster areas due to the very nature of disasters. To address the security problem in disaster scenarios, we propose two pairing-free identity-based AKE (ID-AKE) protocols that have unbalanced computational requirements on the two parties. Compared with existing AKE protocols, the proposed protocols have a number of advantages in disaster scenarios: 1) they are more convenient than symmetric cryptography-based AKE protocols since they do not require any preshared secret between the parties; 2) they are more feasible than asymmetric cryptography-based AKE protocols since they do not require any online server; and 3) they are more friendly to battery-powered and computationally limited devices than pairing-based and pairing-free ID-AKE protocols since they do not involve any bilinear pairing (a time-consuming operation), and have lower computational requirement on the limited party. Security of the proposed protocols are analyzed in detail; and prototypes of them are implemented to evaluate the performance. We also illustrate the application of the protocols through a vivid use case in a terrorist attack scenario.