Skip main navigation

An Introduction to Kerberos

In this step, you will learn about Kerberos, a common authentication protocol often used in the IdAM context.
Businesspeople using tablet computer in server room.

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?
This article is from the free online

Cyber Security Foundations: Reinforcing Identity and Access Management

Created by
FutureLearn - Learning For Life

Our purpose is to transform access to education.

We offer a diverse selection of courses from leading universities and cultural institutions from around the world. These are delivered one step at a time, and are accessible on mobile, tablet and desktop, so you can fit learning around your life.

We believe learning should be an enjoyable, social experience, so our courses offer the opportunity to discuss what you’re learning with others as you go, helping you make fresh discoveries and form new ideas.
You can unlock new opportunities with unlimited access to hundreds of online short courses for a year by subscribing to our Unlimited package. Build your knowledge with top universities and organisations.

Learn more about how FutureLearn is transforming access to education