Kerberos: The Definitive Guide

Encryption

The modern word cryptography is derived from two ancient Greek words, cryptos, which means hidden or secret, and graphein, or writing. Kerberos uses cryptography to provide encryption and decryption of its messages over the network. Therefore, encryption refers to the process of converting a message, or plaintext, into gibberish, which if intercepted, does not reveal the contents of the original message. Governments and corporations have long employed encryption to keep their information secure from prying eyes. The emergence of the Internet, where any network administrator can monitor and read traffic on her network and any traffic passing through her network, has forced software makers to build encryption into every day software programs. Kerberos uses encryption not only to protect the authentication exchanges it sends and receives from snoopers, but also to prevent hackers from creating fake messages.

There are many different ways of encrypting data. These methods are referred to as encryption algorithms, or in Kerberos-speak, encryption types. There are several different encryption types that are supported in Kerberos 5 implementations. The most widely supported encryption type is DES, but work is underway to replace it with Triple DES and the new Advanced Encryption Standard (AES). Another widely used encryption type is the RC4 algorithm, which is used primarily in Microsoft’s implementation of Kerberos.

The advantage of moving to stronger encryption algorithms is ...