SECURING FIBRE CHANNEL FABRICS - Brocade

Elementary Cryptography5This chapter is an introduction to some of the general concepts ofcryptography for an audience that has limited familiarity with cryptography.Many examples are simplified in order to present often highlycomplex concepts in a more palatable format for those unfamiliar withthis field.Cryptography can be used in a SAN environment to solve several problems.Here are some examples of where cryptography can be used in aSAN:• Exchanging data between the management interfaces on theswitch and the management server• Exchanging sensitive data between two data centers over publicnetworks• Protecting data-at-rest on a tape or disk media• Authenticating devices joining a fabric using DH-CHAPThe word “cryptography” is derived from the Greek words “kryptos,”which means hidden, and “graphia,” which means writing, so it is theart of hidden writing. Stated more completely, it is the art, science,skill, or process of communicating in or deciphering messages writtenin code. Scholars certainly have speculated about the first use of cryptography,but one fact is indisputable. The need to exchange or storesensitive information in a manner that only the parties involved couldunderstand has been around for a very long time-certainly several centuries.One of the earliest known ciphers was used by Julius Caesarand is appropriately known as the Caesar cipher or the shift cipher. Itis based on the concept of shifting the alphabet by a pre-determinednumber of letters.Securing Fibre Channel Fabrics 73