Kerberos is a network-based authentication protocol that provides mutual authentication between clients and services, using a ticket system and a central trusted instance, the Key Distribution Center (KDC), which issues the tickets and thereby enables single sign-on. * The Kerberos ticket exchange between client, KDC and service. * Its authentication assertion is the Ticket Granting Ticket. Defined in RFC 4120; the basis of Windows domain logins. Go deeper: Kerberos (Wikipedia) — the full protocol walk-through with KDC, AS, TGS and tickets. RFC 4120 Kerberos V5 — the specification itself.

Quiz Entry - updated: 2026.09.17

What is Kerberos?

Kerberos is a network-based authentication protocol that provides mutual authentication between clients and services, using a ticket system and a central trusted instance, the Key Distribution Center (KDC), which issues the tickets and thereby enables single sign-on.

Client authenticates at the AS and gets a TGT, exchanges it at the TGS for a service ticket, presents it to the service, which authenticates back

* The Kerberos ticket exchange between client, KDC and service. *

Its authentication assertion is the Ticket Granting Ticket. Defined in RFC 4120; the basis of Windows domain logins.

Go deeper:

Kerberos (Wikipedia) — the full protocol walk-through with KDC, AS, TGS and tickets.
RFC 4120 Kerberos V5 — the specification itself.

From Quiz: IAM / IAM Glossary (eCH-0219) | Updated: Sep 17, 2026