Paparelle Iris, Mousavi Faezeh, Scazza Francesco, Bassi Angelo, Paris Matteo, Zavatta Alessandro
Opt Express. 2025 Jul 14;33(14):28917-28934. doi: 10.1364/OE.538593.
Quantum secure direct communication (QSDC) is an evolving quantum communication framework based on transmitting secure information directly through a quantum channel, without relying on key-based encryption such as in quantum key distribution (QKD). Optical QSDC protocols, utilizing discrete and continuous variable encodings, show great promise for future technological applications. We present the first table-top continuous-variable QSDC proof of principle, analyzing its implementation and comparing the use of coherent against squeezed light sources. A simple beam-splitter attack is analyzed by using Wyner wiretap channel theory. Our study illustrates the advantage of squeezed states over coherent ones for enhanced security and reliable communication in lossy and noisy channels. Our practical implementation, utilizing mature telecom components, could foster secure quantum metropolitan networks compatible with advanced multiplexing systems.
量子安全直接通信（QSDC）是一种不断发展的量子通信框架，它基于通过量子信道直接传输安全信息，而不依赖于量子密钥分发（QKD）中基于密钥的加密方式。利用离散和连续变量编码的光学QSDC协议在未来技术应用中显示出巨大潜力。我们展示了首个桌面型连续变量QSDC原理验证，分析了其实现方式，并比较了相干光源与压缩光源的使用情况。通过使用维纳窃听信道理论分析了一种简单的分束器攻击。我们的研究表明，在有损和噪声信道中，压缩态在增强安全性和可靠通信方面优于相干态。我们利用成熟的电信组件进行的实际实现，可促进与先进复用系统兼容的安全量子城域网的发展。
