Stipčević Mario
Photonics and Quantum Optics Research Unit, Center of Excellence for Advanced Materials and Sensing Devices, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia.
Entropy (Basel). 2023 Nov 6;25(11):1518. doi: 10.3390/e25111518.
True randomness is necessary for the security of any cryptographic protocol, including quantum key distribution (QKD). In QKD transceivers, randomness is supplied by one or more local, private entropy sources of quantum origin which can be either passive (e.g., a beam splitter) or active (e.g., an electronic quantum random number generator). In order to better understand the role of randomness in QKD, I revisit the well-known "detector blinding" attack on the BB84 QKD protocol, which utilizes strong light to achieve undetectable and complete recovery of the secret key. I present two findings. First, I show that the detector-blinding attack was in fact an attack on the receiver's local entropy source. Second, based on this insight, I propose a modified receiver station and a statistical criterion which together enable the robust detection of any bright-light attack and thus restore security.
真正的随机性对于任何加密协议的安全性都是必要的，包括量子密钥分发（QKD）。在QKD收发器中，随机性由一个或多个本地的、源自量子的私有熵源提供，这些熵源可以是被动的（例如，一个分束器）或主动的（例如，一个电子量子随机数发生器）。为了更好地理解随机性在QKD中的作用，我重新审视了对BB84 QKD协议的著名“探测器致盲”攻击，该攻击利用强光实现对密钥的不可检测且完全恢复。我给出了两个发现。第一，我表明探测器致盲攻击实际上是对接收方本地熵源的攻击。第二，基于这一见解，我提出了一个改进的接收站和一个统计标准，它们共同能够可靠地检测任何强光攻击，从而恢复安全性。
