Full Definition
What is Authentication?
Authentication is the process of verifying that someone or something is who or what they claim to be. It's a fundamental security control that precedes authorization and is essential for access control.
Authentication Factors
Knowledge Factors Something you know:
- Passwords
- PINs
- Security questions
Possession Factors Something you have:
- Hardware tokens
- Mobile devices
- Smart cards
Inherence Factors Something you are:
- Fingerprints
- Facial recognition
- Voice patterns
- Iris scans
Behavioral Factors Something you do:
- Typing patterns
- Gait analysis
- Usage patterns
Authentication Methods
Password-Based
- Traditional passwords
- Passphrases
- Password managers
Token-Based
- TOTP/HOTP
- Hardware tokens
- Software tokens
Certificate-Based
- PKI certificates
- Smart cards
- mTLS
Biometric
- Fingerprint
- Face ID
- Voice recognition
Modern Approaches
- Passwordless authentication
- Passkeys (FIDO2/WebAuthn)
- Risk-based authentication
- Continuous authentication