The absolute security of quantum communication protocols relies on a critical premise: all participating parties are legitimate users. Ensuring the legitimacy of participant identities is paramount in complex real-world communication environments. Quantum Identity Authentication (QIA), leveraging fundamental principles of quantum mechanics to achieve unilateral or mutual authentication between communicating parties, constitutes an indispensable core component for building a comprehensive quantum secure communication system. It holds significant research value within the field of quantum communication.This review employs a comparative classification approach to systematically outline the research trajectory of QIA protocols. By categorizing protocols based on the required quantum resources and the types of quantum protocols employed, it analyzes the advantages and disadvantages of various categories in terms of efficiency, security, and practicality. Single-photon protocols demand low resources, are easy to implement, and compatible with existing optical components, but require high-efficiency single-photon detectors and exhibit weak noise resistance. Entangled-state protocols offer high security and strong eavesdropping resistance, particularly suitable for long-distance or multi-party authentication. However, they heavily depend on the preparation and maintenance of high-precision, stable multi-particle entanglement sources, resulting in high experimental complexity. Continuous-variable (CV) protocols achieve high transmission efficiency in short-distance metropolitan area networks and are compatible with classical optical communication equipment, making experiments relatively straightforward. Yet, they require high-precision modulation technology and are sensitive to channel loss. Hybrid protocols aim to balance resource efficiency and security while reducing reliance on a single quantum source, but their design is complex and may introduce new attack vectors. Quantum Key Distribution (QKD) framework protocols embed identity authentication within the key distribution process, making them suitable for scenarios requiring long-term secure key distribution, though they often depend on pre-shared keys or trusted third parties. Quantum Secure Direct Communication (QSDC) framework protocols integrate authentication with secure direct information transmission, offering high efficiency for real-time communication, but demand high channel quality. Measurement-Device-Independent QSDC (MDI-QSDC) represents a crucial development direction, resisting attacks on measurement devices. Quantum Teleportation (QT) framework protocols enable cross-node authentication and unconditional security, applicable to quantum relay networks, albeit with high experimental complexity. Entanglement swapping framework protocols can resist conspiracy attacks and are suitable for multi-party joint scenarios, but consume significant resources and rely on trusted third parties. Ping-pong protocol framework supports dynamic key updates and exhibits strong eavesdropping resistance, fitting for temporary authentication on mobile terminals, though it typically supports only unilateral authentication and requires a bidirectional channel.Subsequently, this review details our research group's latest QIA protocols, including a multi-party synchronous identity authentication protocol based on Greenberger-Horne-Zeilinger (GHZ) states, and a tripartite QSDC protocol with identity authentication capabilities utilizing polarization-spatial super-coding. The GHZ-based multi-party synchronous authentication protocol leverages the strong correlations inherent in GHZ states to achieve simultaneous authentication among multiple parties. Through a carefully designed two-round decoy-state detection mechanism, it effectively resists both external eavesdropping and internal attacks originating from authenticated users, thereby enhancing the efficiency and security of identity management in large-scale quantum networks. The core innovation of the polarization-spatial super-coding tripartite QSDC protocol lies in its deep integration of the authentication process with information transmission utilizing the spatial degrees of freedom of single photons. This design accomplishes the identity verification of two senders and the transmission of secret information within a single protocol run, ensuring end-to-end security through a three-stage security check. This "authentication-as-communication" paradigm significantly improves the overall efficiency and practicality of the protocol. Its successful implementation also relies on advancements in quantum memory technology.Finally, the review provides an outlook on future research directions for quantum identity authentication and its application potential within quantum communication. QIA research needs to focus on reducing resource dependency, exploring more efficient protocol designs, further enhancing protocol integration and robustness, prioritizing the development of protocols adaptable to real-world environments, and actively investigating integration with novel scenarios. This comprehensive review aims to provide theoretical research foundations and technical support for the practical development of future quantum identity authentication.
Wang et al. (Wed,) studied this question.