In principle, quantum key distribution (QKD) offers information-theoretic security based on the laws of physics. In practice, however, the imperfections of realistic devices might introduce deviations from the idealized models used in security analyses. Can quantum code-breakers successfully hack real systems by exploiting the side channels? Can quantum code-makers design innovative counter-measures to foil quantum code-breakers? This article reviews theoretical and experimental progress in the practical security aspects of quantum code-making and quantum code-breaking. After numerous attempts, researchers now thoroughly understand and are able to manage the practical imperfections. Recent advances, such as the measurement-device-independent protocol, have closed the critical side channels in the physical implementations, paving the way for secure QKD with realistic devices.
VI. DetectionSecurity 36 A. Countermeasures against detection attacks 36 B. Measurement-device-independent scheme 36 1. Time-reversed EPR QKD 36 2. MDI-QKD protocol 37 3. Theoretical developments 38 4. Experimental developments 39 C. Twin-field QKD 41 VII. Continuous-Variable QKD 42 A. Protocol and security 43 1. Gaussian-modulated protocol 43 2. Discrete modulated protocol 44 3. Security analysis 44 B. Experimental developments 45 C. Quantum hacking and countermeasures 46 VIII. Other Quantum Cryptographic Protocols 47 A. Device-independent QKD 47 B. Some New QKD implementations 48 1. Round-robin DPS QKD 48 2. High-dimensional QKD 50 3. QKD with wavelength-division multiplexing 51 4. Chip-based QKD 51 C. Other quantum cryptographic protocols 53 1. Quantum bit commitment 53 2. Quantum digital signature 53 3. Other protocols 54 IX. Concluding Remarks 55 Acknowledgement 57 A. General questions to QKD 57 References 58 1 Google Q: research.google/teams/applied-science/quantum 2 IBM Q: www.research.ibm.com/ibm-q 3 Rigetti: www.rigetti.com 4 CAS-Alibaba: quantumcomputer.ac.cn/index.html 1. Concern 1. Since RSA is secure under current computational power, we do not need QKD now.
Due to its ability to tolerate high channel loss, decoy-state quantum key distribution (QKD) has been one of the main focuses within the QKD community. Notably, several experimental groups have demonstrated that it is secure and feasible under real-world conditions. Crucially, however, the security and feasibility claims made by most of these experiments were obtained under the assumption that the eavesdropper is restricted to particular types of attacks or that the finite-key effects are neglected. Unfortunately, such assumptions are not possible to guarantee in practice. In this work, we provide concise and tight finite-key security bounds for practical decoy-state QKD that are valid against general attacks.
Quantum key distribution promises unconditionally secure communications. However, as practical devices tend to deviate from their specifications, the security of some practical systems is no longer valid. In particular, an adversary can exploit imperfect detectors to learn a large part of the secret key, even though the security proof claims otherwise. Recently, a practical approach-measurement-device-independent quantum key distribution-has been proposed to solve this problem. However, so far its security has only been fully proven under the assumption that the legitimate users of the system have unlimited resources. Here we fill this gap and provide a rigorous security proof against general attacks in the finite-key regime. This is obtained by applying large deviation theory, specifically the Chernoff bound, to perform parameter estimation. For the first time we demonstrate the feasibility of long-distance implementations of measurement-device-independent quantum key distribution within a reasonable time frame of signal transmission.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.