Post-Quantum Cryptography and Alternating Optimization for Securing Resource-Constrained Devices in 6G Networks

Abstract

The emergence of Post-Quantum Cryptography (PQC) Standards necessitates the adoption of quantum-resistant protocols by resource-constrained devices (RCDs). However, the intensive computational overhead and substantial key sizes of PQC render direct localized execution inefficient. This research proposes an edge computing-enabled PQC framework where RCDs delegate demanding cryptographic tasks to a Post-Quantum Edge Server (PQES) or execute them locally. To preserve data confidentiality against adversarial eavesdropping, a dual physical layer security (PLS) mechanism is integrated: offloading nodes employ wiretap coding, while non-offloading nodes generate artificial noise to actively jam the eavesdropper. We jointly optimize transmit power, PQES resource allocation, and offloading decisions using alternative optimization (AO) to minimize total latency under given resource constraints. Numerical results show that Proposed-AO reduces total latency by up to 41% versus power/capacity-based baselines and 62% versus fully-local computing, with 95% confidence intervals of a few percent over 5,000 Monte Carlo trials.