Distributed Authorization and Reliability-Aware Hardware Security for Photovoltaic Monitoring

Unattended photovoltaic monitoring nodes must maintain authenticated operation under physical access, intermittent connectivity, and environmentally induced key-reconstruction errors. We present a distributed adaptive hardware security framework (DAHSF) combining trusted-gateway threshold authorization, adaptive static random-access memory (SRAM) physical unclonable function (PUF) reconstruction, and incident-driven inspection. Independent epoch secrets separate current authorization from retained historical shares. A nested Bose–Chaudhuri–Hocquenghem (BCH) error-correction scheme reconstructs a fixed 2016-bit SRAM-PUF response, from which universal hashing extracts a 256-bit seed; federated estimation guides decoding effort. The cost and defense trade-offs are assessed under the tested workload, gateway trust, prediction-calibration, and availability conditions. On a 30-node ESP32 platform, DAHSF reduces median startup and mean node power by 4.8% and 4.4% relative to a matched lightweight baseline, with 14.3% more incremental RAM. Predicted-bound decoding reduces mean decoding time from 96 to 59 microseconds. A separate confirmatory cohort records three failures in 120,000 stressed reconstructions; its board-clustered 95% upper bound is 8.6×10−5. In the moderate attack scenario, the full inspection profile reduces compromised-node exposure by 30.0% relative to a risk-threshold policy and by 18.0% relative to frozen propagation-rate estimates. The recorded control workload has no observed 1 ms MPPT deadline misses, while fault injection still bypasses authorization in 168 of 4000 attempts.