1. By Frank Minichini IS 373 Kerberos

2. Introduction Kerberos is a network authentication protocol used to securely send and receive nodes in communication over an unsecured network. Without using a from of authentication, users are vulnerable to attacks, so authentication is necessary. This is why Kerberos was made.

3. Introduction continued…. Kerberos relies on symmetric key cryptography, it also provides mutual authentication. Most modern operating systems such as Windows, Linux, and Macintosh recently have the Kerberos protocol implemented so that way it has become a common standard.

4. Governing Standards Body The MIT Kerberos Consortium was founded so that way it would be known that Kerberos would be established as the universal application platform for the world’s computer networks, as Massachusetts Institute of Technology states.

5. The MIT Kerberos Consortium was made so that way the developers can continue to grow and expand on the original Kerberos protocol that was made originally as an MIT project. The consortium was founded in September of 2007 to let Kerberos continue to expand and extend as a universally stable "single sign-on" mechanism for users of modern computer networks. The consortium provides a tool to allow larger industry participation in the development and funding of Kerberos and it will eventually become the universal single sign-on mechanism that isn’t available just yet.

6. The project is open source and the Consortium encourages active participation with the project to expand it and make it a better one. The website of the MIT Kerberos Consortium can be reached at http://www.kerberos.org.http://www.kerberos.org The IETF (Internet Engineering Task Force) is also working on updating the specifications that will allow encryption and checksum specifications. (MIT Kerberos Consortium)

7. History of Kerberos As stated earlier, Kerberos was originally developed by the Massachusetts Institute of Technology as project known as Athena back in the 1980’s. Kerberos aka Cerebrus is named after a dog from ancient Greek mythology which is described as a three headed guard dog.

8. The original designers of version 4 of the protocol were Steve Miller and Clifford Neuman in which they started as having this version to work with project Athena. V5 became RFC 1510 in 1993 in which this version were to eliminate any security issues that were found in version 4. RFC 1510 eventually became useless and was updated to RFC 4120 in 2005, which is the version now widely used as Kerberos Version 5.

9. The MIT makes sure that implementation of Kerberos is freely available In 2007 of MIT had created and founded the Kerberos Consortium which is now sponsored by many companies such as Microsoft, Apple, Google, and many academic institutions. Windows 2000 was the first windows-based operating system to have Kerberos implemented to work as its authentication protocol. Many UNIX-based operating systems such as Mac OS X, Red Hat Linux, Solaris, and Free BSD have software that use Kerberos authentication services.

10. Standard Specifications How does this work? In order to establish authentication from the client to the server, the client authenticates itself to a special server known as the authentication server and gets a ‘ticket’.

11. The ticket granting server is contacted then by using the client’s ticket it uses it to identify them and perform a service. If the ticket is eligible, the ticket granting server issues another ticket stating it is approved to achieve the service.

12. The client is then forwarded to the service server and uses the new ticket to initiate the service. If everything checks out, then the user is logged in.

13. Advantages The standard is 100% free to use. Kerberos is open source. The availability of Kerberos is used on many recent operating systems such as: - Windows 2000 and up - Mac OS X - Red Hat Linux - Solaris

14. Drawbacks Kerberos requires the usage of the availability of a central server, if a server happens to go down then no one can login. :- ( Another drawback is that, in order to issue proper time stamped tickets, hosts’ clocks must synchronize properly in order for the protocol to work with the timed stamped tickets used in the authentication process.

15. Application of the Standard As mentioned before, Kerberos is used as a software application that can be accessed through a terminal program for Linux operating systems. For Windows, command prompt is used to access the program. The developers of the standard mention on their website that it isn’t intended for individual home use, but enterprise/professional use.

16. Conclusion To conclude, Kerberos is a network authentication protocol that allows proper authentication between a server and a client. It’s a free and open source. It is an essential tool to provide optimum security while communicating between a server and a client.

17. References. Learn-Networking.com. 28 January 2008.. MIT Kerberos Consortium.. RFC4120 Specifications.. How-to Images taken from Learn-Networking.com (http://learn- networking.com/network-security/how-kerberos-authentication- works)