Emergent Response (ER): An Efficient and Scalable Real-time Broadcast Authentication Scheme for Command and Control Messages

Broadcast (multicast) authentication is crucial for large and distributed systems such as cyber-physical infrastructures (e.g., power-grid/smart-grid) and wireless networks (e.g., inter-vehicle networks, military ad-hoc networks). These timecritical systems require real-time authentication of command and control messages in a highly efficient, secure and scalable manner. However, existing solutions are either computationally costly (e.g., asymmetric cryptography) or unscalable/impractical (e.g., symmetric cryptography, one-time signatures, delayed key disclosure methods). In this paper, we develop a new broadcast authentication scheme that we call Emergent Response (ER), which is suitable for time-critical authentication of command and control messages in large and distributed systems. We exploit the semi-structured nature of command and control messages to construct special digital signatures, which are computationally efficient both at the signer and verifier sides. We show that ER achieves several desirable properties that are not available in the existing alternatives simultaneously: (i) Fast signature generation and verification; (ii) immediate verification; (iii) constant size public key; (iv) compact authenticating tag; (v) packet loss tolerance; (vi) being free from time synchronization requirement; (vii) provable security.