ZKP-based authentication for secure D2D salvage transmission in 5G/6G networks

Abstract

In 5G/6G networks, Device-to-Device (D2D) Salvage Transmission (ST) ensures communication continuity when Unreachable User Equipment (X) loses access to the base station. However, securing authentication between X and Salvage User Equipment (S) while maintaining privacy presents a challenge. Traditional authentication methods depend on key exchanges or centralised servers, heightening vulnerability to impersonation and replay attacks. This paper proposes a Zero-Knowledge Proof (ZKP)-based authentication protocol that enables lightweight, privacy-preserving authentication without disclosing private credentials. The approach utilises modular exponentiation and cryptographic hashing, allowing X to demonstrate its legitimacy without revealing its private key. Simulation results indicate that the proposed method achieves low authentication latency ( 1–10 ms), minimal communication overhead ( 80 bytes per session), and high scalability under heavy authentication loads. The scheme provides resistance against man-in-the-middle (MITM), impersonation, and replay attacks, making it highly secure for real-time applications.