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Application Security & Secure Code Review1 / 3

2 min lesson

Authentication & authorization

Walk through each part of "Authentication & authorization", then explain what each one does.

Step 1 of 3

Authentication asks "who are you?" Authorization asks "are you allowed to do this?" Most real-world breaches you'll review aren't login bypasses - they're authorization that someone forgot to write.

The two words, kept straight
Authentication (authn)
Proving identity: passwords, OAuth, SSOSingle Sign-On. One company login (usually via SAML or OIDC) instead of a separate password per tool. Press Enter for the full definition., MFA, session establishment. A failure here = impersonation.
Authorization (authz)
Enforcing permission on every request, per object: can THIS user do THIS to THIS resource? A failure here = privilege escalation or data leak.

Authn happens once at the door; authz must happen on every action behind it.