Article ID: 2026CIP0030
We investigate the design of scalable revocable identity-based authenticated key exchange (RIB-AKE) protocols secure against adaptive adversaries. Our work yields two main positive results. First, we present a generic construction that combines a revocable identity-based key encapsulation mechanism (RIB-KEM) with a standard KEM, improving scalability compared with prior hierarchical approaches. Second, we introduce a direct construction based on the Fiore-Gennaro pairing-free IB-AKE protocol, achieving more than a fifty-fold performance improvement over existing RIB-AKE schemes and enabling straightforward deployment using standard elliptic-curve libraries. The generic construction incurs certain degradation in provable security, whereas the direct construction achieves a tight security bound with respect to the number of identities. In other words, while the first result provides a theoretical guarantee that a generic construction is feasible, the second demonstrates that a concrete scheme can simultaneously improve security and efficiency relative to the generic approach.
