Authentication Security Pattern Authentication verifies that a subject (user, service, device) is who they claim to be before allowing system access. This pattern is a prerequisite for authorization and auditing. When to Use Use this pattern when: - Designing a new login or identity verification system - Reviewing existing authentication mechanisms for flaws - Integrating with external identity providers (OAuth, SAML) - Implementing API authentication (keys, tokens) - Establishing audit trails for user actions Core Components Roles | Role | Type | Responsibility | |------|------|-------------…