Dynamic Group Key Exchange Protocol With Lattice Trapdoor and Re-Encryption Mechanisms
Narn-Yih Lee, Tsai Yuan-Ting · IEEE Access · 2025
Post-quantum group key exchange protocols have become an increasingly critical area of research due to the potential threat quantum computers pose to classical cryptographic schemes. Traditional group key exchange protocols, often based on Diffie-Hellman and other number-theoretic assumptions, are vulnerable to quantum attacks. To address this challenge, we propose a novel group key exchange protocol that leverages lattice-based cryptography. Specifically, our approach utilizes lattice trapdoors and a re-encryption mechanism based on the Ring Learning With Errors (RLWE) problem. This design not only achieves post-quantum security but also enhances efficiency and flexibility in dynamic group settings. A common challenge in most protocols is the computational cost of deriving new keys as group members join and leave. Our approach effectively reduces this cost, making key updates more efficient and practical. Our protocol is proven secure under standard lattice assumptions, providing a promising solution for quantum-resistant group key exchange.