Abstract

Abstract—A Body Area Network (BAN) is a wireless network of health monitoring sensors designed to deliver personalized health-care. Securing inter-sensor communications within BANs is essential for preserving not only the privacy of health data but also for ensuring safety of healthcare-delivery. This paper presents Physiological Signal based Key Agreement (PSKA), a scheme for enabling secure inter-sensor communication within a BAN in a usable (plug-n-play, transparent) manner. PSKA allows neighboring nodes in a BAN to agree to a symmetric (shared) cryptographic key, in an authenticated manner, using physiological signals obtained from the subject. No initialization or pre-deployment is required; simply deploying sensors in BAN is enough to make them communicate securely. Contributions of the paper are as follows: 1) description of PSKA key agreement protocol, 2) analysis of its security characteristics, 3) validation of PSKA utilizing two of the most commonly collected physiological signals photoplethysmogram (PPG) and electrocardiogram (EKG), and 4) cost analysis of executing PSKA, based on a prototype VHDL implementation, and its comparison with Diffie-Hellman key agreement protocol. Our analysis and prototyping shows that PSKA is a viable inter-sensor key agreement protocol for BANs. Index Terms—Body Area Networks, secure communication, physiological signals based key agreement, usable security

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