HybridTrust: PUF-Rooted Hierarchical Blockchain with Layered Zero-Knowledge Proofs for Scalable IoT Device Authentication​

Abstract

Blockchain-based IoT authentication must reconcile security, scalability, and device-level resource efficiency—a trilemma that single-layer architectures cannot resolve simultaneously. We present HybridTrust, a hierarchical authentication system aligned with the device–fog–cloud topology, and evaluate it on a 50-node heterogeneous testbed with container-based scale-out. HybridTrust sustains 160–220 ms end-to-end authentication latency, 8,500 auth/s throughput, and ~90% device-side energy reduction over PKI- and ZK-based baselines, while remaining robust under ~1/3 Byzantine fog nodes and matched-rate DoS traffic. These results follow from a cross-layer cryptographic binding protocol that chains PUF-rooted device identities through fog-level Bulletproof batch commitments to cloud-level SNARK-attested aggregation: devices use PUFs and fuzzy extractors for hardware-rooted secrets with constant-time overhead, fog nodes aggregate commitments into batch Bulletproofs and sign attestation summaries, and the cloud generates a single Groth16 proof per window over fog signatures—avoiding the prohibitive cost of embedding Bulletproof verification inside a SNARK and yielding O(1) on-chain verification independent of device count. Analytical modeling projects sub-second latency at 10^6-device scale.​