logins

A login is the process by which a user proves an claimed identity to a computer system, allowing access to resources that require authentication. Typical credentials are a user identifier (such as a username or email address) and a secret password; alternative credentials may include biometric data, a hardware security key, or an access token. The login process may also involve selecting an account or user role.

Authentication is the act of confirming the user’s identity; authorization determines what the authenticated user is permitted to do. A login is the common user-facing method to initiate authentication, after which the system issues a session identifier or token to authorize subsequent requests.

Common methods include password-based logins, often supplemented by multi-factor authentication (MFA), which combines something the user knows with something the user has or something the user is. Other approaches include passwordless options (magic links, one-time codes), biometrics (fingerprint, facial recognition), and hardware security keys via standards such as FIDO2/WebAuthn. Single sign-on (SSO) and federated identities let users authenticate once for multiple services via an identity provider, using protocols like OAuth or OpenID Connect.

Security considerations: use TLS to protect credentials in transit, store passwords securely with salted hashing algorithms (e.g., bcrypt, Argon2); avoid reversible storage. Implement rate limiting, account lockouts, and monitoring to deter brute-force and credential-stuffing. Encourage MFA, educate against phishing, and use password managers. Consider session management and token security; use short-lived tokens and secure cookies, with proper invalidation on sign-out.

Usability and accessibility concerns include providing clear feedback on failed logins, supporting password recovery, offering accessible alternatives for clients with disabilities, and providing options for passwordless or SSO where appropriate.