Which of the following is an authentication protocol that uses a ticket-based system for access control?

PKI (Public Key Infrastructure) uses digital certificates and public-key cryptography for secure communication and identity verification, not a ticket-based system for access control.

Ciphers are algorithms used for encryption and decryption, which are components of security but not an authentication protocol itself.

WPA2 (Wi-Fi Protected Access 2) is a security protocol used to secure wireless networks, providing encryption and authentication for Wi-Fi traffic, but it is not a ticket-based system for general access control.

Kerberos is an authentication protocol that relies on a trusted third party (Key Distribution Center) to issue tickets. These tickets grant users access to services without repeatedly sending their credentials over the network, making it a ticket-based system for access control.