Security engineering is the process of incorporating security controls into an information system so that the controls become an integral part of the system’s operational capabilities. It is similar to other systems engineering activities in that its primary motivation is to support the delivery of engineering solutions that satisfy pre-defined functional and user requirements, but it has the added dimension of preventing misuse and malicious behavior. Those constraints and restrictions are often asserted as a security policy.

In one form or another, security engineering has existed as an informal field of study for several centuries. For example, the fields of locksmithing and security printing have been around for many years. The concerns for modern security engineering and computer systems were first solidified in a RAND paper from 1967, "Security and Privacy in Computer Systems" by Willis H. Ware. This paper, later expanded in 1979, provided many of the fundamental information security concepts, labelled today as Cybersecurity, that impact modern computer systems, from cloud implementations to embedded IoT.

Recent catastrophic events, most notably 9/11, have made security engineering quickly become a rapidly-growing field. In fact, in a report completed in 2006, it was estimated that the global security industry was valued at US $150 billion.

Security engineering involves aspects of social science, psychology (such as designing a system to "fail well", instead of trying to eliminate all sources of error), and economics as well as physics, chemistry, mathematics, criminology architecture, and landscaping. Some of the techniques used, such as fault tree analysis, are derived from safety engineering.

Other techniques such as cryptography were previously restricted to military applications. One of the pioneers of establishing security engineering as a formal field of study is Ross Anderson.