Quantum key distribution without authentication and information leakage

Quantum key distribution (QKD) is the most widely studied quantum cryptographic model that exploits quantum effects to achieve information-theoretically secure key establishment. Conventional QKD contains public classical post-processing steps that require authentication to prevent impersonation and maintain security. However, a major limitation of QKD is it cannot perform authentication by itself, and thus requires a separate authentication mechanism. In addition, these public classical steps also have information leakage which subjects QKD to additional attack strategies and reduces the final key rate. In this work, we propose a new QKD variant that removes the need for a separate authentication mechanism, eliminates information leakage, and achieves a substantially higher key rate. By having two more protocol keys than conventional QKD and no public classical steps, our design achieves (almost) perfect information-theoretic security with the protocol keys reusable.