authenticationRequired

AuthenticationRequired is a term used in software systems to indicate that access to a resource requires proof of identity. It often appears as a configuration flag, policy setting, or documentation cue that authentication must be performed before granting access. In practice, it signals that requests lacking valid credentials should be rejected.

In web and API contexts, enforcement typically manifests through HTTP status codes. When a request lacks valid credentials, servers commonly respond with 401 Unauthorized, often accompanied by a WWW-Authenticate header that describes the supported authentication schemes (such as Bearer or Basic). If a request includes valid credentials but the authenticated user lacks permission to the resource, a 403 Forbidden may be returned. These responses help clients distinguish between missing authentication and insufficient authorization.

Common authentication mechanisms include token-based schemes (for example, OAuth tokens or JSON Web Tokens), session cookies, and API keys. In stateless systems, credentials are presented with each request; in stateful systems, a server-side session may be used. Resources marked as authenticationRequired typically require clients to supply valid credentials to proceed.

Security and design considerations include clear documentation of access policies, consistent use of appropriate status codes, secure handling and storage of credentials, token lifetimes and revocation, and adherence to the principle of least privilege to minimize risk if credentials are compromised.