## 4 Security Threat Landscape in 5G Networks
### Security Solutions for mMTC  
As the risk landscape for mMTC in 5G networks is complex, securing these networks requires innovative solutions. Research and developments in this domain have centered on several key strategies, as shown in Table 7. One of the strategies involves using lightweight cryptographic methods suitable for resource-constrained devices. Such methods aim to secure data transmission without overly burdening the device's computational and power resources. For example, symmetric encryption algorithms, such as the advanced encryption standard (AES), can offer a balance between security and computational efficiency [66]. \begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline
**Security Solutions for mMTC** & **Description** & **Advantages** & **Challenges** & **Use Cases** \\ \hline \multirow{4}{*}{Lightweight cryptographic methods} & Utilizes lightweight cryptographic techniques suitable for resource-constrained mMTC devices. & Minimizes computational and power overhead. & - & May provide lower levels of security compared to the heavier encryption methods. & - & Secure data transfer in mMTC devices with limited resources. \\  & Aims to secure data transmission without imposing a significant computational or power burden. & - & Suitable for devices with limited resources. & - & May provide lower levels of security compared to the heavier encryption methods. \\ \hline \multirow{4}{*}{Distributed security mechanisms} & Implements distributed security mechanisms where the security workload is shared among multiple devices or network nodes. & Enhanced resilience against attacks. & - & Requires coordination among multiple devices or & - & Protection against DoS and DDoS attacks in mMTC networks. \\  & It prevents a single point of failure and is particularly effective against DoS attacks. & - & Presventive network congestion due to attacks. & - & Complex to implement and manage. \\ \hline \multirow{4}{*}{Intrusion detection systems (IDSs)} & Utilizes IDS to monitor network traffic and identify suspicious activities. & - & Provides real-time threat detection. & - & May generate false positives. & - & Early detection of security threats in mMTC applications. \\  & It plays a critical role in the timely detection and mitigation of potential threats in mMTC environments. & - & Alerts network administrators potential security breaches. & - & May generate false positives. & - & Early detection of security threats in mMTC applications. \\ \hline \end{tabular}
\end{table} 
Table 7: Security solutions for mMTC in 5G networks [65; 66; 67]. Distributed security mechanisms represent another approach, where the security workload is shared among multiple devices or network nodes. This approach can prevent a single point of failure and can be particularly effective against DoS and DDoS attacks [51]. Intrusion detection systems (IDSs) and IPS also have a role to play in securing mMTC. These systems can monitor network traffic and identify suspicious activities, allowing for the timely detection and mitigation of potential threats. AI algorithms have shown promise in improving security in mMTC. These techniques can analyze vast amounts of network data to identify patterns and anomalies, helping to detect and prevent cyberattacks. In addition, strict authentication and access control mechanisms are crucial for securing mMTC in 5G networks. They can prevent unauthorized devices from gaining access to the network or accessing sensitive data [67]. Table 7 offers an in-depth exploration of security solutions tailored for mMTC in 5G networks. It delineates various approaches from lightweight cryptographic methods designed for devices with limited computational resources to more sophisticated solutions like machine learning and artificial intelligence for anomaly detection. Each approach is scrutinized for its advantages and challenges, providing insights into their applicability under specific use cases.