More and more attention is being directed towards the Non-Orthogonal Multiple Access (NOMA) technology due to its many advantages such as high data rate, enhanced spectral and energy efficiency, massive connectivity, and low latency. On the other hand, secure data transmission remains a critical challenge in wireless communication systems since wireless channels are, in general, exposed. To increase the robustness of NOMA systems and overcome the issues related to wireless transmission, several Physical Layer Security (PLS) schemes have been recently presented. Unlike conventional security algorithms, this type of solutions exploits the dynamicity of the physical layer to secure data using a single iteration and minimum operations. In this paper, we survey the various NOMA-based PLS schemes in the literature, which target all kinds of security properties. From this study, we have noticed that the majority of the research work in this area is mainly focused on data confidentiality and privacy and not on other security properties such as device and source authentication, key generation, and message integrity. Therefore, we discuss the PLS data confidentiality schemes for NOMA and their limitations, challenges, and countermeasures, and we propose different methods to address the remaining security properties.

由于非正交多路访问（NOMA）技术具有许多优势，例如高数据速率，增强的频谱和能效，大规模连接性和低延迟，因此越来越受到人们的关注。另一方面，由于通常暴露无线信道，因此安全数据传输在无线通信系统中仍然是关键的挑战。为了增加NOMA系统的健壮性并克服与无线传输有关的问题，最近提出了几种物理层安全性（PLS）方案。与传统的安全算法不同，这种类型的解决方案利用物理层的动态性来通过一次迭代和最少的操作来保护数据。在本文中，我们调查了文献中各种基于NOMA的PLS方案，针对各种安全属性。从这项研究中，我们注意到，该领域的大部分研究工作主要集中在数据机密性和隐私性上，而不是在其他安全属性（例如设备和源身份验证，密钥生成和消息完整性）上。因此，我们讨论了NOMA的PLS数据机密性方案及其局限性，挑战和对策，并提出了解决剩余安全属性的不同方法。