When analysing Quantum Key Distribution (QKD) protocols several metrics can be determined, but one of the most important is the Secret Key Rate. The Secret Key Rate is the number of bits per transmission that result in being part of a Secret Key between two parties. There are equations that give the Secret Key Rate, for example, for the BB84 protocol, equation 52 from [1, p.1032] gives the Secret Key Rate for a given Quantum Bit Error Rate (QBER). However, the analysis leading to equations such as these often rely on an Asymptotic approach, where it is assumed that an infinite number of transmissions are sent between the two communicating parties (henceforth denoted as Alice and Bob). In a practical implementation this is obviously impossible. Moreover, some QKD protocols belong to a category called Asymmetric protocols, for which it is significantly more difficult to perform such an analysis. As such, there is currently a lot of investigation into a different approach called the Finite-key regime. Work by Bunandar et al. [2] has produced code that used Semi-Definite Programming to produce lower bounds on the Secret Key Rate of even Asymmetric protocols. Our work looks at devising a novel QKD protocol taking inspiration from both the 3-state version of BB84 [3], and the Twin-Field protocol [4], and then using this code to perform analysis of the new protocol.

翻译：在分析量子密钥分发（QKD）协议时，可以确定多个指标，但其中最重要的指标之一是秘密密钥率。秘密密钥率是指每次传输中能够成为双方之间秘密密钥一部分的比特数。存在一些公式可以计算秘密密钥率，例如，对于BB84协议，文献[1, p.1032]中的方程52给出了给定量子比特误码率（QBER）下的秘密密钥率。然而，得出此类方程的分析往往依赖于渐近方法，即假设通信双方（以下简称Alice和Bob）之间发送了无限次传输。在实际实现中，这显然是不可能的。此外，某些QKD协议属于非对称协议类别，对此类协议进行上述分析更加困难。因此，目前有许多研究转向了一种称为有限密钥方案的不同方法。Bunandar等人[2]的工作生成了代码，利用半定规划为即使是非对称协议的秘密密钥率提供下界。我们的工作旨在设计一种新颖的QKD协议，该协议同时借鉴了3态版本BB84 [3]和双场协议[4]的思路，并利用上述代码对新协议进行分析。