Flexible Multicast Authentication for Time-Triggered Embedded Control Network Applications

Security for wired embedded networks is becoming a greater concern as connectivity to the outside world increases. Protocols used in these networks omit support for authenticating messages to prevent masquerade and replay attacks. The unique constraints of embedded control systems make incorporating existing multicast authentication schemes impractical. Our approach provides multicast authentication for time-triggered applications by validating truncated message authentication codes (MACs) across multiple packets. We extend this approach to tolerate occasional invalid MACs, analyze our approach through simulated attacks, and give an upper bound on the probability of successful attack. This approach allows a tradeoff among per-packet authentication cost, application level latency, tolerance to invalid MACs, and probability of induced failure, while satisfying typical embedded system constraints.