Auth & Authorization Patterns

Authentication (who are you?):

• Use a battle-tested library — do not roll your own crypto.

• Hash passwords with bcrypt/argon2; never MD5/SHA1 for passwords.

• Use short-lived JWTs (15–60 min) with refresh tokens; store refresh tokens securely.

• Implement MFA for sensitive operations.

Authorization (what can you do?):

• Check authorization on every request, not just at login.

• Enforce RBAC or ABAC at the service layer, not the UI.

• Apply principle of least privilege: grant minimal permissions needed.

OAuth2 / OIDC:

• Use the Authorization Code flow with PKCE for user-facing apps.

• Validate iss , aud , exp , and nonce claims on every token.

Session management:

• Regenerate session ID after login (session fixation prevention).

• Set HttpOnly and Secure flags on session cookies.