Quantum key distribution without authentication and information leakage

Quantum key distribution (QKD) is the most extensively researched quantum cryptographic protocol, leveraging quantum phenomena to enable information-theoretically secure key establishment. Conventional QKD systems rely on authenticated classical post-processing channels to prevent impersonation attacks. However, QKD inherently lacks authentication capabilities, necessitating an external authentication mechanism. Furthermore, the classical post-processing steps introduce information leakage, exposing QKD to additional attack strategies and diminishing the final key rate. In this study, we introduce a novel QKD protocol that eliminates the need for separate authentication, prevents information leakage, and significantly improves the achievable key rate. By removing public classical channels entirely, our design attains perfect secrecy with the use of two reusable pre-shared keys.