HySecure: FPGA-Based Hybrid Post-Quantum and Classical Cryptography Platform for End-to-End IoT Security

As the Internet of Things (IoT) continues to expand into mission-critical and long-lived applications, securing low-power wide-area networks (LPWANs) such as Narrowband IoT (NB-IoT) against both classical and quantum threats becomes imperative. Existing NB-IoT security mechanisms terminate at the core network, leaving transmission payloads exposed. This paper proposes HySecure, an FPGA-based hybrid cryptographic platform that integrates both classical elliptic curve and post-quantum schemes to achieve end-to-end (E2E) security for NB-IoT communication. Our architecture, built upon the lightweight RISC-V PULPino platform, incorporates hardware accelerators for X25519, Kyber, Ed25519, and Dilithium. We design a hybrid key establishment protocol combining ECDH and Kyber through HKDF, and a dual-signature scheme using EdDSA and Dilithium to ensure authenticity and integrity during handshake. Cryptographic functions are evaluated on FPGA, achieving a 32.2× to 145.4× speedup. NS-3 simulations under realistic NB-IoT configurations demonstrate acceptable latency and throughput for the proposed hybrid schemes, validating their practicality for secure constrained IoT deployments and communications.