Verifying user identity and credentials
Authentication is the process of verifying the identity of users or entities attempting to access a system. Operating systems employ various authentication mechanisms to ensure that only authorized users can access resources. Common authentication methods include: 1) Password-based authentication - Users provide a secret known only to them. 2) Token-based authentication - Users possess a physical or digital token (e.g., smart cards, RSA tokens). 3) Biometric authentication - Users provide biological characteristics (e.g., fingerprints, facial recognition). 4) Multi-factor authentication - Combining multiple methods for enhanced security. Operating systems store user credentials securely using techniques like hashing and salting passwords. Authentication systems also handle account lockout policies, password expiration, and session management. Modern systems often integrate with enterprise authentication services like LDAP, Active Directory, or Kerberos for centralized identity management. Understanding authentication mechanisms is crucial for system administrators to configure secure access controls and for developers to implement proper authentication in applications.