Cryptography has been used for thousands of years for storing hidden messages in writing (Davies, 1997). Cryptography itself is part of cryptology, which also includes cryptanalysis. Cryptanalysis involves the attempt to obtain the original message from an encrypted message, but without determining the algorithms or knowing the keys that created the original encrypted message. Cryptography, which is the topic of this paper, is the actual development of the encrypted messages, and using codes to create secure communication of information (Whitman & Mattord, 2011).
As mentioned, cryptography has been around for thousands of years in one form or another. Various forms of “secret writing” were performed and enhanced over time, but there was no remarkable improvement until the Renaissance. At that point, the science of cryptography became an area of study, with techniques being written down. It was brought on by a time of war, competition and political intrigue within the Italian, Venetian and British states (Davies, 1997).
The most dominant form of cryptography was nomenclator, which was developed from simply ciphers where each letter is replaced by a different letter. Substitute letters are part of a fixed table. This technique was very easy to decipher because of commonly used letters and words, but was refined over time to diminish this defect. One technique used to refine nomenclature was the use of polyalphabetic substitution, which uses many cipher alphabets and removes the issue of letter frequency (Davies, 1997).
In the early 1900’s is when many more complex machines were created and were used extensively for cryptography in World War II. The Enigma was one such machine, and was used by the Germans pervasively. Interestingly, an American developed a basis for the machine several years before the invention of the Enigma by the German’s, but was treated very badly by the United States military, leading to his financial collapse. Eventually, the United Kingdom devoted extensive resources to build a cryptanalysis capability at a factory scale, along with the United States, to intercept messages from the Enigma and decipher them. This did eventually pay off in the war. The moral of this, though, is that cryptanalysis must be ahead of cryptography, which will use the most advanced technology available at the time to develop the most complex cipher available (Davies, 1997).
Post World War II along with the rapid advancement of information technology has given rise to capabilities that have fundamentally altered cryptography. These are the Data Encryption Standard, published by the United States Government, and public key (asymmetric) cryptography. These have expanded the interest of cryptography around the world and brought cryptography to a whole new professional level (Davies, 1997).
Today, cryptography is used pervasively throughout electronic communication, which is the most common form of communication today. However, it has shifted to...