noninterference

Noninterference is a term used in different fields to describe the absence of unwanted influence from one party or component on another. While its exact meaning varies by context, it generally denotes preserving autonomy, separation, or secrecy by limiting cross-influence.

In international relations, noninterference refers to a state’s policy of not meddling in the internal affairs of other states. It is closely tied to sovereignty and is often contrasted with interventionism or coercive actions. Proponents argue it supports peaceful coexistence and respect for territorial integrity, while critics may view it as enabling oppression or human rights abuses when applied to other regimes.

In information security and computer science, noninterference is a formal property that ensures high-security inputs do not affect observable low-security outputs. Introduced by Goguen and Meseguer in 1982, it provides a rigorous way to reason about information flow and confidentiality. Systems designed to satisfy noninterference aim to prevent leaks of sensitive data through observable behavior. Variants and extensions address issues such as declassification, intransitive information flow, and multi-level security policies, often employing formal models and automated verification.

In practice, achieving noninterference requires appropriate governance, architectural choices, and policy measures. In political contexts, this may involve diplomatic commitments, treaties, and mechanisms to monitor compliance. In technical contexts, it involves access control, isolation, secure programming practices, and explicit handling of information flows.

See also: nonintervention, information flow control, security policy.