There are several authentication methods, including: 1. Password-based authentication: Users enter a username and password to access a system or resource. 2. Multi-factor authentication (MFA): Requires additional verification steps beyond a password, such as a code sent to a phone or biometric data. 3. Biometric authentication: Uses unique physical characteristics, like fingerprints, facial recognition, or iris scans, to verify identity. 4. Public Key Authentication: Uses a pair of cryptographic