User-Authenticated Device-Independent Quantum Secure Direct Communication Protocol

Device-Independent Quantum Secure Direct Communication (DI-QSDC) enhances quantum cryptography by enabling secure message transmission without relying on the trustworthiness of the devices involved. This approach mitigates risks associated with compromised or untrusted devices, common in traditional quantum communication. In this paper, we propose the first of its kind DI-QSDC protocol with user identity authentication. This ensures the authenticity of both the sender and receiver prior to message exchange. We then discuss the security of the proposed protocol against common attacks, demonstrating that no eavesdropper gains any information from either the quantum or the classical channel. Next, we implement the protocol on IBM's quantum hardware and evaluate its performance in a realistic noisy environment. Additionally, by simulating common attack models, we showcase that the protocol is secure against any eavesdropper in the channel. These findings highlight the protocol's robust security and practical feasibility for real-world secure quantum communication.