auth-implementation-patterns

Build secure, scalable authentication and authorization systems using industry-standard patterns and modern best practices. Authentication (AuthN) : Who are you? Authorization (AuthZ) : What can you do? Session-Based: Token-Based (JWT): OAuth2/OpenID Connect: - Implementing user authentication systems - Securing REST or GraphQL APIs - Adding OAuth2/social login - Implementing role-based access control (RBAC) - Designing session management - Migrating authentication systems - Debugging auth issues - Implementing SSO or multi-tenancy - Verifying identity (username/password, OAuth, biometrics) - Issuing credentials (sessions, tokens) - Managing login/logout - Permission checking - Role-based access control (RBAC) - Resource ownership validation - Policy enforcement - Server stores session state - Session ID in cookie - Traditional, simple, stateful - Stateless, self-contained - Scales horizontally - Can store claims - Delegate authentication - Social login (Google, GitHub) - Enterprise SSO - Never Store Plain Passwords : Always hash with bcrypt/argon2 - Use HTTPS : Encrypt data in transit - Short-Lived Access Tokens : 15-30 minutes max - Secure Cookies : httpOnly, secure, sameSite flags - Validate All Input : Email format, password strength - Rate Limit Auth Endpoints : Prevent brute force attacks - Implement CSRF Protection : For session-based auth - Rotate Secrets Regularly :...