A Hybrid Post-Quantum Cryptographic Framework for Secure 5G/6G and Massive IoT Networks

Abstract

The imminent maturity of large-scale quantum computing threatens the confidentiality and authenticity guarantees of the public-key primitives-RSA and elliptic-curve cryptography that currently secure next-generation communication networks, including 5G/6G core and radio-access segments, software-defined edge infrastructures, and massive Internet-of-Things (IoT) deployments. “Harvest-now, decrypt-later” adversaries put long-lived network traffic at risk much before cryptographically relevant quantum machines come into existence. This paper presents QR-SecNet, a Quantum-Resistant Security Framework that combines a lattice-based key-encapsulation mechanism (ML-KEM), a stateless hash-based signature scheme (SLH-DSA) and a classical elliptic-curve exchange within a single hybrid handshake so that the security of a session depends on the hardness of at least one of two mathematically unrelated problems. The framework also includes a crypto-agility controller, which is able to negotiate cipher suites based on device capabilities and network conditions, mitigates downgrade attacks, and supports incremental migration, maintaining interoperability with legacy endpoints. QR-SecNet was evaluated on an emulated 5G/6G network testbed against five representative baselines-RSA-3072, ECDHE-P256, a standalone ML-KEM exchange, a standalone ML-DSA signature scheme, and Classic McEliece using latency, throughput, computational cost, and estimated post-quantum security margin as metrics. Results show that QR-SecNet completes a hybrid handshake in 11.8 ms on average, sustains a throughput of 1,740 connections per second, and preserves at least 128 bits of classical and 192 bits of post-quantum security margin, outperforming standalone post-quantum baselines in latency by 17-46% while remaining within 2.1 ms of the fastest single-primitive scheme.