A Resilient Runtime-Verification Fabric for Security Monitoring of Critical Edge-IoT Infrastructure
Protecting critical infrastructure increasingly depends on continuously verifying large IoT fleets against formal security specifications at runtime. Yet the runtime-verification (RV) pipelines proposed for this task are typically single-host prototypes whose monitors read a shared log file, with no resilience to the failures such deployments incur: a crash or overload silently drops events, clock skew corrupts the ordering metric monitors require, a time-triggered "node has gone silent" property cannot fire when the network itself falls silent, and one slow consumer stalls the pipeline. Each failure is silent: the monitor keeps emitting verdicts over a corrupted view. We present RV-Fabric, a resilient delivery layer that carries the hierarchy over two brokers (MQTT for device ingest, a durable stream broker for backend delivery) and re-establishes five continuity guarantees: durable delivery under crashes, a trusted event order, progress under total silence, consumer isolation and flow control under bounded overload, each an invariant conditioned on broker durability. Above the transport, RV-Fabric makes evidence completeness part of runtime-verification semantics: every verdict carries a status (sound, degraded, incomplete or unavailable) derived from delivery gaps, retention pressure and liveness, so an incomplete stream cannot yield an unqualified all-clear. Under controlled fault injection on a containerised testbed, measured against a fault-free oracle using the real MonPoly engine, the shared-log baseline misses six of seven injected incidents, reporting each as an unqualified all-clear, whereas RV-Fabric preserves all seven; removing a delivery mechanism reintroduces silent loss, removing isolation costs only timeliness. Two published critical-infrastructure datasets, water-SCADA and IoT/IIoT, replay end-to-end.