Authentication: passwords, verification codes, biometrics and 2FA/MFA compared

What this note covers

1. Authentication versus authorisation, and the three factors
2. Passwords: strength, storage and policy
3. Verification codes: SMS, email and authenticator apps
4. Biometrics: convenience with permanent consequences
5. Comparing verification codes with biometrics
6. Writing authentication into algorithms and recommendations

6 sections · 11 key terms & formulas · 6 common mistakes