Security policy

Security policy is a definition of what it means to be secure for a system, organization or other entity. For an organization, it addresses the constraints on behavior of its members as well as constraints imposed on adversaries by mechanisms such as doors, locks, keys, and walls. For systems, the security policy addresses constraints on functions and flow among them, constraints on access by external systems and adversaries including programs and access to data by people.

If it is important to be secure, then it is important to be sure all of the security policy is enforced by mechanisms that are strong. There are organized methodologies and risk assessment strategies to assure completeness of security policies and assure that they are completely enforced. In complex systems, such as information systems, policies can be decomposed into sub-policies to facilitate the allocation of security mechanisms to enforce sub-policies. However, this practice has pitfalls. It is too easy to simply go directly to the sub-policies, which are essentially the rules of operation and dispense with the top level policy. That gives the false sense that the rules of operation address some overall definition of security when they do not. Because it is so difficult to think clearly with completeness about security, rules of operation stated as "sub-policies" with no "super-policy" usually turn out to be rambling rules that fail to enforce anything with completeness. Consequently, a top-level security policy is essential to any serious security scheme and sub-policies and rules of operation are meaningless without it.^[1]

Multiple regulatory and compliance frameworks mandate formal security policies as a foundational element of organizational information security programs.

The Health Insurance Portability and Accountability Act (HIPAA) Security Rule requires covered entities and business associates to implement reasonable and appropriate policies and procedures to comply with each of the rule's standards and implementation specifications for the protection of electronic protected health information (45 CFR 164.316).^[2] These policies must be maintained in written form, reviewed periodically, and updated in response to environmental or operational changes. The December 2024 Notice of proposed rulemaking (NPRM) to overhaul the HIPAA Security Rule would require written security policies to be reviewed and updated at least annually, with specific documentation requirements for technology asset inventories, risk assessments, incident response plans, and business associate security certifications.^[3]

The ISO/IEC 27001 standard requires organizations to establish an information security policy appropriate to the purpose of the organization as a prerequisite for certification.^[4] The National Institute of Standards and Technology (NIST) Cybersecurity Framework identifies security policy development as a core function of the "Govern" category, while SP 800-53 includes the PL (Planning) control family requiring organizations to develop and disseminate security and privacy plans and policies.^[5]