## 1 Introduction  
This work is an extension for a previous paper that has been presented in 2020 International Conference on Communications, Signal Processing, and their Applications (ICCSPA) [1]. Security is one of the fundamental challenges that must be addressed in all types of networks, particularly with the tremendous number of connections and services planned in 5G and beyond. In this context, physical-layer security (PLS) has emerged as a critical and reliable approach to effectively addressing the security concern [2, 3]. PLS does not depend on the exchange of security keys between authorized endpoints since there is no necessity for decryption and encryption operations, as in higher-layer security techniques [4, 5]. As a result, PLS is more suitable for use in 5G networks and beyond. That is, there is no additional complexity introduced to the current complicated networks. [PERSON] was the first to propose the notion of PLS [6], which was then expanded upon by [PERSON] [7]. The PLS notion claimed that the confidentiality of private information is assured when the main channel (the link between the transmitter and the legitimate receiver) is more reliable than the wiretap channel (the one between the transmitter and the eavesdropper) [8]. \(\kappa\)-\(\mu\) fading model is one of the general fading distributions, which have been confirmed by field measurement campaigns to better suit the experimental data compared to other known distributions, such as Rayleigh, Rician, and Nakagami-\(m\) fading [9]. \(\kappa\)-\(\mu\) distribution suits the line-of-sight (LOS) applications with the two physical parameters; \(\kappa\) and \(\mu\). \(\kappa>0\) is recognized as the ratio between the total power of the dominant components and the power of the scattered waves, while \(\mu>0\) demonstrates the number of the multipath clusters. \(\kappa\)-\(\mu\) fading channel includes some of the well-known channels as special cases, which is a reason for its flexibility property, such as Rician (\(\mu=1\) and \(\kappa=\) LOS component in the Rician channel), Rayleigh (\(\kappa=0,\mu=1\)), Nakagami-\(m\) ( \(\kappa=0,\mu=m\)), and the one-sided Gaussian (\(\kappa=0,\mu=0.5\)) distributions [9]. Recently, various forms of networks have been investigated under the premise of cascaded channels rather than single regular channels. These channels presume that the entities in the networks are moving or that they reside in dense scattering regions [10]. The principle of cascaded channels suggests that the signal that leaves the transmitter does not travel directly to the receiver without encountering objects and obstacles along the way. In addition, the received signal is composed of the multiplication of multiple rays reflected from the objects obstructing the path [11]. Cascaded channels have a variety of applications, which has made them intriguing for recent research in signal propagation modeling. These applications include mobile-to-mobile/vehicle-to-vehicle communications (M2M/V2V) [12], the multi-hop relaying systems, and the keyhole channels in multiple-input-multiple-output (MIMO) system models [13; 14]. Physical-layer security performance over cascaded fading channels has recently been thoroughly investigated. PLS was studied for a system model consisting of a transmitter, a receiver, and one eavesdropper in terms of the secrecy outage probability (SOP) and the strictly positive secrecy capacity (SPSC) over double Rayleigh fading channel in [15] and over double Nakagami-\(m\) fading channel in [16]. Similar analyses were performed in [17] over cascaded \(\alpha-\mu\) fading channel and in [12; 18] over cascaded Nakagami-\(m\) fading channel. In [18], the secrecy performance was explored for two scenarios of one eavesdropper and two eavesdroppers. Secrecy was investigated over cascaded Fisher-Snedecor \(\mathcal{F}\) fading channels using stochastic geometry in [19] in the presence of randomly distributed eavesdroppers.