Abstract

Quantum key distribution (QKD) exploits the laws of quantum physics to generate shared secret cryptographic keys and can detect eavesdroppers during the key generation process. However, previous QKD research has focused more on theory than practice. QKD is the most mature application of the quantum information field, offering the means for two parties to generate secure cryptographic keying material. Employing the laws of quantum physics, QKD can detect eavesdroppers during the key generation process, in which unauthorized observation of quantum communication induces discernible errors. However, QKD is a nascent technology where real-world systems are constructed from nonideal components and deployed in uncertain operational environments, which can adversely impact system security and performance. In this article, we study the performance impact of QKD implementation nonidealities and practical engineering limitations, evaluating three system examples using a modularized simulation framework. We also explore the QKD security–performance trade space to gain additional understanding of critical design tradeoffs associated with interactions between physical components and system-level considerations such as hardware, software, and protocols. Such evaluations provide insight and inform designers, researchers, and users when selecting among competing solutions; decision makers can also use them to guide future investments and developmental efforts. Our research team focuses on bridging the gap between QKD theory and practice. Theoretical and experimental physicists are working to advance QKD technology, but few are strongly focused on evaluating and improving the implementation of realized systems. For a general introduction to QKD, see Chip Elliot’s “Quantum Cryptography.”