Cryptography Tools for the Systems Administrator

Bruce Alan Wynn and Michael Carpenter

Recently, cryptography and crypto tools have received considerable publicity in technical forums. Much glamor is associated with this previously little-known topic, but once you peel back the flash and glitter, how important is cryptography to the casual systems administrator? What tools are available, and what can they do for you? What is the cost of implementing these tools, and how valuable are the benefits? In the following article, we will explore these and other questions.

The History of Ciphers and Cryptography

Cryptography has been around since the invention of writing and arose from a desire to keep secrets. A cipher is an algorithm that translates one word or letter into another. Most ciphers can be reversed, giving the original message. While ciphering a message will make it unreadable to the casual observer, some information about the encoded message will still be available: the number of words, the number of letters in each word, and possibly even the frequency of each letter. This makes ciphers easy to use, but also easy to break.

Around 400 B.C., the Spartans developed the scytale, which consisted of a rod around which a piece of "paper" was wrapped. Text was written on the paper, and when the paper was removed from the rod, all that appeared on the paper was a string of meaningless letters. To decode the message, you had to use a rod of the exact diameter as the rod on which the message was written.

Julius Caesar developed what has become known as the Caesar Cipher. He wrote out all letters of the alphabet, and beneath them he wrote the alphabet again, but shifted it three letters.