CREST Practitioner Security Analyst (CPSA) 2026 – 400 Free Practice Questions to Pass the Exam

Kerberos operates on the principle of tickets, which is central to its authentication process. In a typical Kerberos setup, when a user wants to access a service, they first authenticate themselves to the Kerberos Key Distribution Center (KDC). Upon successful authentication, they receive a ticket-granting ticket (TGT). This TGT is then used to request service tickets for specific applications or services from the KDC.

The use of tickets allows Kerberos to provide a secure means of authentication without sending passwords over the network. When a user presents a service ticket to access a resource, the ticket proves to the service that the user has already been authenticated by the KDC, which enhances security and helps prevent replay attacks.

In contrast, while public key encryption, session tokens, and hash functions may play roles in different aspects of security protocols, they are not the fundamental mechanism by which Kerberos operates. The ticket-based approach allows for single sign-on functionality and ensures that users authenticate only once while still being able to access multiple services securely.