What Is National Security?

National security is the condition by which a nation-state and its population are protected from threats to their sovereignty, territorial integrity, critical infrastructure, and public welfare. Historically centered on military defense, the concept has broadened considerably over the past several decades to encompass cyber threats, supply chain vulnerabilities, energy security, pandemic preparedness, and the security of the digital systems that underpin modern economies. Engineering and technology play a central role in national security, both as a source of threats that must be defended against and as the primary means by which defensive capabilities are designed, deployed, and maintained.

National security intersects with numerous engineering disciplines, including electrical engineering, communications, computer science, control systems, and aerospace engineering. Federal agencies and research bodies in the United States, including the Department of Defense, the Department of Homeland Security, and the intelligence community, sponsor a large share of the country's engineering research precisely because of this intersection.

Cyber Warfare

Cyber warfare refers to offensive and defensive operations conducted in and through cyberspace to damage, disrupt, or destroy an adversary's information systems, communications networks, or control infrastructure. Nation-state actors conduct these operations to gather intelligence, degrade military readiness, or coerce civilian behavior through attacks on financial systems, energy grids, and communications networks. The discipline draws on cryptography, network security, vulnerability research, and adversarial machine learning. The CISA resource on securing critical infrastructure against cyber threats describes the U.S. government's framework for identifying and managing risks to the 16 sectors that CISA considers critical to national security, economic stability, and public health.

Control System Security

Control system security addresses the protection of industrial control systems (ICS), including supervisory control and data acquisition (SCADA) systems and distributed control systems (DCS), which manage physical processes in electric grids, water treatment facilities, pipelines, and manufacturing plants. These systems were originally designed for reliability and real-time performance in isolated networks; as operational technology (OT) environments became connected to corporate IT networks and the internet, they inherited cybersecurity exposures that their architectures were not built to handle. The NIST Special Publication 800-82 Guide to Industrial Control Systems Security provides the canonical framework for assessing and improving the security posture of ICS environments within a national security context.

Critical Infrastructure Protection

Critical infrastructure protection (CIP) is the discipline concerned with identifying, assessing, and reducing risks to the systems and assets that, if incapacitated or destroyed, would have a debilitating effect on national security, national economic security, or public health and safety. In the United States, 16 critical infrastructure sectors have been identified, spanning energy, water, transportation, financial services, communications, and healthcare, among others. Effective CIP requires coordination among government agencies, private sector operators who own most of the relevant infrastructure, and international partners, since disruptions to interconnected systems routinely cross jurisdictional and national borders. The PNNL explainer on critical infrastructure protection outlines the analytical methods that national laboratories use to model and mitigate cascading failures across interconnected infrastructure systems.

Applications

National security considerations have applications in a wide range of engineering and policy disciplines, including:

• Defense electronics, including radar, electronic warfare, and secure communications systems
• Cybersecurity of military and civilian communications networks
• Energy grid resilience and protection against physical and cyber attacks
• Satellite and space systems used for surveillance, navigation, and command and control
• Supply chain security for semiconductor and critical materials sourcing in defense-relevant industries