An Introduction to Kerberos

Introducing Kerberos

On the local area network, one of the longstanding forms of authentication protocols is Kerberos. Kerberos uses the concept of a ticket system to allow computers to establish a secure channel of communication with each other. This is typically between a client and a server.

Kerberos was named after the three-headed dog, the character from Greek mythology. “Cer-beros”, or “Ker-beros”, guarded the gates to Hades, and was therefore a form of access management.

Kerberos requires a trusted third party that both the server and the client already trust. This can limit the utility of Kerberos as we already need an existing trust framework to be in place.

How is it limited?

Well, Kerberos helps to prevent replay attacks and eavesdropping attacks. So if somebody captures some of these tickets, it prevents the utility of them by limiting the life of those tickets in terms of time. For this reason, we need time synchronization. We need our clients and servers all to be using the same time. If the time is slightly different, then the authentication processes can fail for that reason.

Investigate and share: Research Kerberos further and report back what you have found by taking the following into consideration:

• how does Kerberos work?
• how many roles does Kerberos allow?
• how does Kerberos get implemented?
• can you find some examples of where Kerberos was used?