Abstract: Currently,aeronautical communications system is facing the challenge of spectrum saturation and lack relevant security standards and defense measures,which makes aeronautical communications data vulnerable to illegal interception and tampering.To enhance the security of aeronautical communications system and optimize the efficiency of ground-to-air communications,a lightweight aeronautical broadband communications system security authentication protocol based on symmetric encryption has been proposed.This protocol aims to ensure that aircraft and ground gateway can mutually authenticate identities and securely transmit data.By relying on pre-shared root keys and message authentication code verification operations,the protocol has an average message overhead of 59 bytes,effectively circumventing the certificate management issues faced by existing aeronautical communications system with public key authentication schemes while maintaining its lightweight nature,and providing a robust network security barrier for the identity authentication process.Through formal modeling verification with the Scyther tool and system packet analysis testing,the protocol’s high efficiency and reliability in bandwidth-limited aeronautical communications environments have been confirmed.

Key words: Security authentication protocol, Aeronautical broadband communications system, Symmetric encryption, Key agreement, Cybersecurity