## 5 A Case Study on Reliable Pipeline Monitoring Using Cyber Physical Sensor Networks
### Remote Infrastructure Security Concerns  
In the earlier wireless sensor network deployments, most networks were deployed without any security measures including the early implementation of the famous ZigBee protocol for sensing plane. The scenario changed and security measures were introduced at different layers when a multi-platform interoperability demonstration failed drastically since they interpreted the basic command code from a completely different network that was actually meant for the coordinator node in order to change channels, hence completely initiating a blackout in the system. At earlier stages, there were no measures for the sensor network to determine whether the message belonged to their own network or some other network. The basis for the failure was the requirement of an authentication mechanism, which led the system to interpret any type of message that was intrinsically relevant to the sensor domain [71]. When deploying wireless sensor networks in industry, particularly related to industrial automation applications, the consequence of architectural failures will be more than a mere loss of sensing information. With faulty, inaccurate or altered information being delivered to the control station, the system is potentially vulnerable to physical damage. For example, a sensor transmitting data to the valve controller or a direct motor informing it about the system speed requirements or component processing levels being too high could cause reversible damage to the whole industrial setup. Even in practical terms, a failed security aspect in the developed system or a revelation of weakness in the deployed sensor network could result in a loss of engineering power. For a standalone secure network, security requirements need to be fulfilled at the protocol as well as system implementation and deployment level. Some examples of well-developed security protocols for sensor planes include the WirelessHART and ISA100.11a protocols related to industrial automation. The ZigBee Smart Energy related protocols have also undergone extensive review by security experts and numerous implantation tests. In particular, the WirelessHART protocol is the key enabling technology for most of the sensor network deployments around the world that are potential candidates for security concerns. The end users of the securely deployed networks put trust in the application in terms of provisioning processing control information reliably and in confidence between two authenticated sensor nodes [72]. In CPSN industrial applications, as new protocols emerge, particularly related to Internet of Things, the security measures need to be compatible with the IP communication procedures [73]. Once CPSN is set up, the realm of security concerns changes drastically. All such concerns need to be addressed with thorough understanding, assessment and a defense mechanism (Table 6). The major challenges and security related problems arise due to the decentralized nature and heterogeneity of protocol and hardware used to interconnect devices. The physical interactions between devices over an un-trusted environment open up potential vulnerabilities. Such issues are a major concern for CPS based on sensor networks with strict privacy and resource constraints. To assess the level of security implementation for a CPSn oriented system, diverse security goals need to be defined with major attacker models developed in relation to system complexity. The security metrics could be used to provide a scale of implementation with a holistic view of the complete system taking into account external vulnerabilities. Finally, defensive mechanisms for cyber systems normally must ensure continuous interaction between physical devices to highlight a clear gap between the role of attacker and defender [74]. These interactions could be complex enough depending upon the system distribution and environmental reliability.