## 4 Security Challenges and Solutions in 5G Network and LPWAN-IoT
### Endogenous Security Challenges and Solution in 5G and LPWAN-IoT  
Wireless signals use electromagnetic waves as the carrier to transmit information openly in space. However, the propagation of wireless signals also exposes the endogenous\" gene\" defects of electromagnetic waves, such that anyone within the signal coverage area can eavesdrop or attack the physical layer [82]. OTA of the physical layer in 5G and LPWAN for IoT solutions are also exposed to endogenous security problems. Traditionally, the existing security mechanisms primarily follow the encryption mechanism in communication, which cannot withstand security issues caused by the openness in wireless channels. Various encryption mechanisms for wireless networks have earlier been cracked. For example, the KASUMI encryption algorithm in 3G was cracked due to loopholes [83]. The existing security mechanisms are being improved to address the past security issues. For example, 4G uses Snow3G/AES/Zuc-based hierarchical keys to mitigate security attacks such as SS7 signaling hijacking in 3G. But it was difficult to deal with the unknown risks and security breaches in the present system. Therefore, it is paramount to address endogenous security problems. This can be achieved by the study of new security mechanisms based on the essential attributes of wireless communication security to deal with known and unknown security threats in wireless systems [82]. Consequently, endogenous security theory can be used to resist both known and unknown security threats. Recently, this theory has made a significant breakthrough as an upcoming security research area in technical advancement and system development [84]. Hence, the research on wireless endogenous security is in the gradual stage. Wireless \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Cryptographic Mechanisms** & **Type of Algorithm** & **Concerned Security** & **Applicable LPWAN/5G** \\ \hline Symmetric Encryption & Advance encryption (AES) & Confidentiality & 5G and Most LPWAN devices \\ \hline Asymmetric Encryption & RSA/Elliptic Curve Crypto & Key management & 5G and most 3 GPP LPWANs \\ \hline Key Agreement & Diffie-Hellman (DH) & Key agreement & 5G, NB-IoT, LTE-M, Cat1, EC-GSM-IoT \\ \hline Hashing Functions & SHA-1, SHA-2, and SHA-3 & Integrity & 5G, LTE-M, Cat1, NB-IoT, LoRaWAN \\ \hline Digital Signature & Digital Signature Algorithm (DSA) & Digital signature & 5G, LTE-M, and Cat1 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Cryptographic mechanisms and their encryption algorithms in 5G and LPWAN-IoT. Figure 7: Proposed 5G Security by China IMT-2020 (5G) Promotion Group. channel naturally has endogenous security attributes that are dynamic, heterogeneous, and redundant. Based on this, a distinctive endogenous security structure of wireless communication systems can be designed to safeguard the security and reliability of data transmission from the transmitter to receiver. Wireless endogenous security technology has been advocated for the protection of the confidentiality, reliability, and integrity of information in a few recent research. For instance, a wireless channel was used as an executor to realize a secured transmission technology [81] based on random signal scrambling [85; 86; 87]. Physical layer key generation technology based on a \"one-time pad\" [88; 89; 90] is also realized. The realization of the secured communication was brought about by the endogenous security strategy at the physical layer transmission, which enables only users on the legal channel to correctly demodulate the signal, while the signals on the channels in other locations are scrambled and unrecoverable. This endogenous security mechanism can be implemented on LPWAN-IoT for secured smart city applications. Endogenous security deployment framework in 5G security architecture is a current research focus of the industry. The current development trend in 5G network architecture involves features like clouds, SDN, and virtualization.