How do you handle user authentication and security?

User authentication is implemented using industry-standard security practices. Features include: secure password hashing (passwords never stored in plain text, use bcrypt), password requirements (minimum length, complexity rules), password reset (secure email-based reset), session management (automatic logout after inactivity), two-factor authentication (SMS or authenticator app codes for sensitive apps), role-based access (admin, manager, user permissions), single sign-on (SSO with Google, Microsoft, or custom), account lockout (prevent brute-force attacks), and audit logging (track who accessed what). We implement OAuth 2.0 for third-party authentication ensuring users never share passwords with your app. Sessions use secure, HTTP-only cookies preventing XSS attacks. All authentication happens over HTTPS encrypting credentials in transit. For high-security applications, we can implement: biometric authentication, device verification, IP restrictions, or multi-factor authentication. Authentication systems comply with OWASP security guidelines and Australian Privacy Principles for data protection.