Post-quantum Entropy as a Service for Embedded Systems
摘要
Robust entropy management in embedded systems is fundamental for cryptographic security. This work presents a complete framework for distributing quantum-generated entropy from Quantum Random Number Generators (QRNGs) to resource-constrained devices using post-quantum cryptography (PQC). The server-side contribution implements a Quantum Entropy as a Service (QEaaS) architecture featuring dual entropy access methods: direct quantum entropy via custom OpenSSL providers and mixed quantum-enhanced entropy through Linux system pools. The HTTP API serves HTTPS clients through an Nginx reverse proxy with OpenSSL, and embedded CoAP clients via CoAP-HTTP proxies using wolfSSL for DTLS and PQC algorithms. The client-side contribution extends libcoap’s Zephyr support and implements a client that builds libcoap and wolfSSL into Zephyr RTOS. We create a custom BLAKE2s-based entropy pool as replacement for the standard ESP32 entropy drivers while maintaining the Zephyr entropy API, combining local hardware entropy with received quantum entropy.