Kerberos Authentication Working in detail(Part-1)
In this post we are going to see that how Kerberos Authentication works in detail, I think this is the best in depth explanation of how Kerberos Authentication work. We are publishing it into parts, this one is the part - 1. This post have two scenes, next two scenes will be posted in next post. This was originally written by Bill Bryant, February 1988.
This dialogue provides a fictitious account of the design of an open-network authentication system called "Charon." As the dialogue progresses, the characters Athena and Euripides discover the problems of security inherent in an open network environment. Each problem must be addressed in the design of Charon, and the design evolves accordingly. Athena and Euripides don't complete their work until the dialogue's close.
When they finish designing the system, Athena changes the system's name to " Kerberos ," the name, coincidentally enough, of the authentication system that was designed and implemented at MIT's Project Athena. The dialogue's "Kerberos" system bears a striking resemblence to the system described in Kerberos: An Authentication Service for Open Network Systems presented at the Winter USENIX 1988, at Dallas, Texas.
What is Kerberos?
Kerberos is a network authentication protocol. It is designed to provide strong authentication for client/server applications by using secret-key cryptography. A free implementation of this protocol is available from the Massachusetts Institute of Technology. Kerberos is available in many commercial products as well.
The Internet is an insecure place. Many of the protocols used in the Internet do not provide any security. Tools to "sniff" passwords off of the network are in common use by malicious hackers. Thus, applications which send an unencrypted password over the network are extremely vulnerable. Worse yet, other client/server applications rely on the client program to be "honest" about the identity of the user who is using it. Other applications rely on the client to restrict its activities to those which it is allowed to do, with no other enforcement by the server. Some sites attempt to use firewalls to solve their network security problems. Unfortunately, firewalls assume that "the bad guys" are on the outside, which is often a very bad assumption. Most of the really damaging incidents of computer crime are carried out by insiders. Firewalls also have a significant disadvantage in that they restrict how your users can use the Internet. (After all, firewalls are simply a less extreme example of the dictum that there is nothing more secure than a computer which is not connected to the network --- and powered off!) In many places, these restrictions are simply unrealistic and unacceptable.
Kerberos was created by MIT as a solution to these network security problems . The Kerberos protocol uses strong cryptography so that a client can prove its identity to a server (and vice versa) across an insecure network connection. After a client and server has used Kerberos to prove their identity, they can also encrypt all of their communications to assure privacy and data integrity as they go about their business. Kerberos is freely available from MIT, under copyright permissions very similar those used for the BSD operating system and the X Window System. MIT provides Kerberos in source form so that anyone who wishes to use it may look over the code for themselves and assure themselves that the code is trustworthy. In addition, for those who prefer to rely on a professionally supported product, Kerberos is available as a product from many different vendors. In summary, Kerberos is a solution to your network security problems. It provides the tools of authentication and strong cryptography over the network to help you secure your information systems across your entire enterprise. We hope you find Kerberos as useful as it has been to us. At MIT, Kerberos has been invaluable to our Information/Technology architecture.
Athena an up and coming system developer.
Euripides a seasoned developer and resident crank.
Two scenes will be published in next post, so stay tuned for that. We hope you really like it, please share it with your fellow learners, so that they can also learn about the Working of Kerberos Authentication Protocol.