Why Authentication Fails

Authentication fails when systems rely on fragile secrets, predictable user behavior, and weak recovery paths. This lesson introduces the practical reasons password-based sign-in breaks down: reuse, phishing, credential stuffing, poor storage, excessive friction, and recovery processes that bypass otherwise strong controls.

Students will learn to view authentication as a complete system rather than a login box. The focus is on failure patterns and design tradeoffs that set up the rest of the course: stronger password practices, MFA, passkeys, and risk-aware authentication.