The infrastructure security has always been on the highest level for the US government. Still, the September 11, 2001 was the breaking point which is considered to be the start for heightened interest in critical infrastructure protection, both in public and in private sectors. To understand the main purpose of the research, it is crucial to check the main notions which are going to be considered, critical infrastructure in private sector. Critical infrastructure is the notion which identifies physical and computer-based systems, like telecommunications, banking, transportation, water and energy resources, etc. The private sector of the country’s economy is characterized by the organizations which are not controlled by the state, like private firms, companies, banks and other private non-government organizations (Radvanovsky and McDougall 5). Thus, the main purpose of the research is to consider the main security strategies the private sector uses in the relation to the protection of critical infrastructures. The USA has a Department of Homeland Security which helps the private sector to cope with the problems it may face. Critical Infrastructure Protection Challenges for Private Sector There are a number of different challenges a private sector should cope with the purpose to organize critical infrastructure protection properly. There are a number of different normative laws which are aimed at analyzing those challenges and offering some decisions to solve them. Considering the challenges in addressing cybersecurity, the following key ones may be identified: the organizational stability should be achieved, the roles and capacities of the cybersecurity should be considered and the awareness should be increased, the efficient partnership with stakeholders should be considered, the information exchange should be on the high level (Powner 12). Private sector also faces other challenges, like securing control systems. One the one hand, technological innovations are involved in the sphere and allow specialists to control the process by means of different facilities. On the other hand, the specialized security technologies for control systems are not invented yet due to a number of reasons. Moreover, there are some ideas that securing control systems are not justified economically that create some problems. Finally, the security control systems may become the issue for conflicts on the basis of the priority notion (Dacey 18). There are a number of challenges private sector faces in the informational sphere. National Infrastructure Protection Center is the organization that helps the private sector cope with those challenges as the establishment of the correct information-sharing relations with the state is the first step for dealing with the problem. These challenges should be faced both by the private sector and by the Department of Homeland Security, even though it is the state institution, the security is going to be on the highest level in the private sector only when the government supports it. Introduction to Threat and Risk Analysis Models To conduct the critical infrastructure protection properly and on the highest level, the risk assessment in the sphere should be provided. Risk management and critical infra