## 4 Security Challenges and Solutions in 5G Network and LPWAN-IoT
### Security Challenges and Solutions in LPWAN-IoT and 5G  
#### 4.2.1 Security Challenges and Solutions in LPWAN-IoT  
Confidentiality, integrity, authenticity, and availability (CIA2) are the essential part of security requirements in information assets and LPWAN-IoT. Confidentiality ensures that only authorized users can have access to data/classified information which cannot be smooped on by unauthorized users. Integrity ensures the ability to safeguard the data/classified information from any intrusion throughout the communication process. Authentication ensures that the device transferring data and the data being transferred is legitimate. Availability ensures that information and network resources are continuously available for legitimate users when needed. CIAA can be implemented in PHY, MAC, and the network layer. Various security mechanisms including the physical layer security (PLS) mechanism are used to avoid data/security breaches by an eavesdrop-attacker. Incorporating cryptographic algorithms used in the MAC offers an advanced level of security. Security mechanisms at the network layer also of some level of security [23]. Security threats occur due to the exposure of the devices connected to the internet through the LPWAN wireless air interface [5]. Security breaches and vulnerabilities in LPWAN-IoT for smart cities and remote areas applications are high because of the massive MTC connectivity. Encryption of the application interface and network request access is essential to avoid possible intrusions. Over-the-air (OTA) security is a key facility that ensures devices are not exposed to security risks over a lengthy duration [65]. OTA can be implemented as an alternative to the authentication method. It is costly to deploy OTA security in non-cellular LPWAN technologies because of the heterogeneity with other user equipment (UE)/devices. Strong encryption and authentication mechanisms such as advanced encryption standards AES) are used in many networks for secure data transmission. However, AES is difficult to implement in some LPWAN solutions dueto the low complexity of LPWAN technology. Other security mechanisms which are based on cryptographic standard protocols include Diffie-Hellman (DH) which uses key exchange/management, and Rivest-Shamir-Adleman (RSA) which is used to authenticate digital signatures/key transport. Also, cellular LPWAN uses the subscription identity module (SIM)-based authentication schemes to provide security protection  
Some of the major security challenges common to LPWAN-IoT are enumerated below:  
* Flash network traffic: It is expected that the number of end-user devices which will be supported by LPWAN will grow exponentially in 5G due to massive MTC. This will cause substantial changes in the network traffic patterns, thus giving room to security loopholes and malicious activities [13];
* Jamming attack: This is one of the main problems for LPWAN-IoT. Malicious entities can send a powerful radio signal in the same transmit power as the legitimate application devices and interrupt the radio transmissions [5]. Such jamming signals can adversely affect LPWAN transmission. For instance, concurrent LoRa or Sigfox transmissions at the same frequency and spreading factor can interfere with each other;
* DoS attacks: DoS and DDoS (distributed denial of service) attacks can exhaust computing and network resources such as energy, storage, and connectivity [66]. This will prevent legitimate users from gaining access. Intermittent requests or explicitly crafted requests generated toward the legitimate network in enormous numbers by illegal LPWAN users can mar the normal operation of the network or bring the network to a halt;
* Security of radio interface keys: In previous wireless network generations, including 4G, the radio interface encryption keys are generated in the home network and transmitted to the visited network over insecure links that exposes the keys [66];
* Compromising devices and Network keys: Devices including the microcontroller unit (MCU) can be compromised.