Multi-Layered Continuous Authentication Protocol for Medical Wireless Body Area Networks

Abstract

The medical Wireless Body Area Networks (WBANs) are still susceptible to session hijacking attacks since most of the protocols are only authenticated once, during session establishment. We propose the Multi-Layered Continuous Authentication Protocol (MCAP) based on Elliptic Curve Cryptography, ECG biometrics and Physical-layer Security, which operates as a continuous authentication loop to reduce the mid-session attack window. This three-layer integration is, to our knowledge, not previously demonstrated for WBANs, and is supported by a closed-form trust-degradation bound. Phase I: Mutual authentication with forward secrecy using BAN logic and ProVerif. Under all mobility conditions, the biometric layer provides an 86.7% TPR/3.3% FAR, while MCAP provides 100% impostor blocking under the Clinical conditions. AND-gate fusion decreases the acceptance rate of impostors in degraded environments (46.2%→3.0% Outdoor, 76.4%→4.9% Exercise). The latency for Phase I is ~55ms and the trust score does not fall below the re-authentication threshold over a sustained adversarial session (Wilcoxon p<0.001). The results are simulation based; Hardware validation is left for future work