Methods and Techniques for Enhancing Physical Security of Critical Infrastructures

In the last years, research on Critical Infrastructure Protection (CIP) has become one of the primary matters for the development of modern societies. Water, power, banking, transportation and communication systems are only a few examples of essential infrastructures to daily human activities and their protection is a concept relating to the preparedness and response to serious incidents that could threaten them. The term protection is a broader concept in which three main aspects can be individuated: safety, security, and emergency. The safety aspects are out of the scope of this thesis, indeed, the focus is on security. In particular, this investigation will address the concerns of security tied to physical and human factors without considering those related to the cyber ones. This is because the present work is born in the railway context, where the attention is usually oriented to the physical aspects of security since, until now, a common practice has been to realize dedicated connections and isolated networks. With respect to the emergency aspects, only the advantages that a security solution can induce will considered. Physical security is one of the most fundamental aspect of the protection. It concerns the use of physical controls for protecting premises, sites, facilities, buildings or other physical assets belonging to the critical sectors. The application of physical security is the process of using layers of physical protective measures to prevent unauthorized access or harm. This harm can involve terrorism, theft, destruction, sabotage, vandalism, espionage, and similar. A crucial element which contributes to improve the protection of critical infrastructures seamlessly is the technology. Thanks to fast technological progress, it is possible to build complex surveillance systems able to integrate heterogeneous sources which can monitor environments potentially at risk. In this way, resilience may be accomplished, for example, through hardening the system by adding redundancy and robustness. However, for enhancing significantly the protection level, integration of different technologies is not enough, but a collaborative approach is essential. A strong protection calls for interoperability not only among ICT systems, but also among different operators, organizations, companies, and any other entity belonging to the public security sector. Nevertheless, the security designer must determine how best to combine elements like fences, barriers, sensors, procedures, security systems, and security personnel into a Physical Security System (PPS) that can achieve the protection objectives. For this reason, another important element is to conduct a systematic evaluation in which quantitative and/or qualitative techniques are used to predict overall system effectiveness, by identifying exploitable weaknesses in asset protection for a given threat. The original contribution of this thesis is to provide methods for enhancing effectiveness and reliability of integrated security systems in order to guarantee an adequate protection level. To achieve the desired level of protection, a two phase approach is proposed combining proactive and reactive strategies. The first one involves the vulnerability assessment based on quantitative methods and the second one introduces an interoperability framework. Specifically, this thesis is the result of research funded by Ansaldo STS, a leader company in railway industry, and carried out also thanks to involvement in research projects about security theme (such as SECUR-ED and METRIP)