Post-Quantum Cryptography for Secure 5g and Iot: Lattice-Based Encryption Schemes

The impending advent of cryptographically relevant quantum computers threatens classical public-key primitives that underpin 5G and IoT security, including key exchange, authentication, and device onboarding. Ultra-dense networks, constrained endpoints, and long device lifetimes heighten exposure to “harvest-now, decrypt-later” risks. Mobile operators and IoT platform providers need migration ready cryptography that fits radio-access latency budgets, scales to billions of low-power nodes, and integrates cleanly with 3GPP and IETF protocols without degrading quality of service. Many post quantum options impose prohibitive bandwidth and compute costs or lack deployment guidance tuned to network slices and massive machine-type communications. We propose a lattice-based encryption and key-encapsulation framework grounded in Module-LWE/LWR assumptions. The design pairs an IND-CCA-secure KEM for control plane bootstrapping with lightweight AEAD for user-plane data, delivered through a hybrid handshake combining classical ECDH with a post-quantum KEM to ensure continuity during transition. Parameter tiers align with eMBB, URLLC, and mMTC device classes. Implementation emphasizes constant-time polynomial arithmetic, NTT-accelerated convolution, centered-binomial noise sampling, public-key compression, and stateless hash-based signatures for attestation. A gNB-assisted enrollment workflow and session-key rotation via 5G NAS/RRC are specified. Analytical modeling and prototype measurements indicate sub-millisecond encapsulation on ARM Cortex-M33 microcontrollers and ~1.5 ms on RAN baseband paths, while handshake message growth remains within existing NAS and RRC budgets. In ns-3 simulations of dense mMTC topologies, the hybrid handshake achieves >99.99% success under 1% packet loss, and energy profiling shows <5% battery impact for weekly rekeying. Security analysis demonstrates resistance to known lattice attacks at NIST Levels 3–5, forward secrecy via ephemeral KEMs, downgrade resistance through authenticated algorithm negotiation, and post compromise security with frequent rekeying.