## 5 LPWAN Security Analysis
### Integrity  
Data integrity refers to the preservation of network data accuracy, completeness and reliability [63]. As explained by authors in [64], data integrity aims to prevent unintentional or intentional manipulation, alteration, deletion, or modification of network information and commands by unauthorized intruders. Typical integrity attacks include replay attack, sybil attack, and wormhole attack. A replay attack can be described as an attack whereby a valid packet transmission is maliciously manipulated [65]. The authors in [65] explained that replay attacks are perpetrated by intruders who capture network traffic and communicate with authorized users/nodes while acting as a legitimate node. With regards to wormhole attack, [66] described the attack as a situation whereby an intruder receives network packets at one location, forwards the retrieved packets to another node, and continues to replay the packets within the entire network. Furthermore, wormhole attack are closely tied to other attacks such as eavesdropping and replay attacks. In [15] the authors explained that a wormhole attack can be performed using two devices: Sniffer and jammer. The sniffers capture the network packets and decide on whether to jam the packets. Once a decision to jam has been made, a notification is sent to the jammer to jam the packet immediately. To prevent wormhole attack, the authors in [67] proposed that the two devices (sniffer and jammer) must be kept separate to prevent sniffer from recording the original message and to circumvent jamming of the messages. In sybil attack, a malicious device from intruders illegally creates numerous identities in the network and the identities are used to gain a disproportionately large influence within the network [68]. The analysis of LPWAN data integrity have been a major topic in the literature as major LPWAN standards are known to be highly vulnerable to integrity attacks. In an analysis of LPWAN integrity vulnerabilities, the authors in [15; 69] cautioned that Sigfox is highly vulnerable to replay attacks and they strongly advised against its deployment for critical applications. However, the authors in [69] advised that better replay protection must be integrated at a higher layer by end users, thus minimizing the already small payload size. Similarly, the authors in [17] explained that Weightless-P network are also prone to replay and wormhole attacks. Various works in the literature have discussed numerous security solutions for LPWAN integrity attacks' mitigations. While presenting a comprehensive analysis on LoRaWAN security issues, the authors in [70] proposed a dual option (default option and security enhanced option) security protocol for preventing replay attack. The security protocol was developed to support mutual authentication, secret key exchange, perfect forward secrecy, and end-to-end security between node devices. Similarly, to establish a secured end to end LPWAN communication, the authors in [20] proposed a replay attack mitigation scheme involving two different AES keys. The authors used a frame counter which involves two different 128-bit AES session keys for upstream and downstream messages exchange, respectively, for the blockage of repeated transmission of packets. For robustness, the authors further encrypted each message using the XOR operation with the corresponding key. Also, the authors in [71] presented a replay attack scenario that typically occur at the join request transfer process. In a detailed mitigation solution to the menace, the authors proposed the deployment of sniffed join request messages approach. In another security assessment study, the authors in [22] proposed an AES-128 based Secure Low Power Communication (SeLPC) method for enhancing the security level of LoRaWAN communication by periodically updating encryption key (AppSKey) and lookup table (D-Box) on both end-devices and application-server sides.