Authentication and authorization are two fundamental concepts in security, often used together but serving different purposes: Authentication: This is the process of verifying a user's identity. It ensures that the person or system trying to access a resource is who they claim to be. Common authentication methods include passwords, biometrics, OTPs, and multi-factor authentication (MFA). Authorization: This determines what an authenticated user is allowed to do. Once a user is authenticated, authorization defines their access levels and permissions for specific resources, such as viewing, editing, or deleting data. Authorization is typically enforced through role-based access control (RBAC) or permission policies.