A Brief Overview of Cryptography
Because most individuals could not read, the earliest form of encryption was simply writing a message (New World, 2007). The term cryptography is derived from the Greek terms kryptos and graphein, which mean hidden and writing, respectively (Pawlan, 1998).
Early cryptography was exclusively concerned with turning messages into unreadable groupings of figures in order to secure the message’s substance while it was being transported from one location to another. In the present period (New World, 2007), cryptography has evolved from fundamental message confidentiality to encompass some phases of message integrity checking, sender/receiver identity authentication, and digital signatures, among other things (New World, 2007).
The necessity to conceal signals has existed since mankind emerged from caves, began living in groups, and decided to take this civilisation seriously. The idea that we had to work against each other appeared and spread as soon as there were separate groups or tribes, coupled with rank brutality, secrecy, and crowd manipulation. The first types of cryptography were discovered in the cradle of civilisation, which includes the modern territories of Egypt, Greece, and Rome.
As early as 1900 B.C., Egyptian scribes utilised hieroglyphs in an unconventional manner, perhaps to conceal the meaning from those who could not understand it (Whitman, 2005).
The Greeks devised the method of wrapping a tape around a stick and then writing the message on the wound tape. The words would be meaningless after the tape was unravelled. The message’s receiver, of course, would have a stick of the same diameter and would use it to understand the message. The Caesar Shift Cipher was the Roman system of cryptography. It employed the concept of shifting letters by a predetermined number (three was a popular historical option), and therefore, creating the message using the letter-shift. The message would then be deciphered by shifting the letters back by the same number (Taylor, 2002).
A Monoalphabetic Cipher is something like the Caesar Shift Cipher. It’s easy to see why this encryption scheme is so easy to crack. All one has to do is go down the alphabet, juxtaposing the first letter with each consecutive letter. The message is decrypted at each iteration to see if it makes sense. The code has been broken when it appears as a readable message. Another method for breaking monoalphabetic cyphers is to employ frequency analysis, which is credited to the Arabs around 1000 C.E. (New World, 2007). This approach is based on the assumption that certain letters, such as the letter “e” in English, are repeated more frequently than others. Armed with this knowledge, a person may go through a message and check for the repeated use, or frequency of use, of a specific letter, and attempt to substitute known commonly used letters (Taylor, 2002).
Once the Greek way of using a stick was discovered, it was simply a matter of experimenting with different diameter sticks until the message became readable.
Until the Middle Ages, there were no significant improvements or advancements in the art or science of cryptography. By that time, all Western European countries had adopted cryptography in some form or another. The primary application of cryptography was to communicate with diplomats. Due to his invention of polyalphabetic substitution, Leon Battista Alberti was dubbed “The Father of Western Cryptology.” His method involved fitting two copper discs together. Each one was imprinted with the alphabet. The discs were rotated every few words to vary the encryption mechanism, restricting the use of frequency analysis to crack the cypher (Cohen, 1990). Polyalphabetic substitution underwent several alterations and is most often attributed to Vigenere, while Rubin contends that he had nothing to do with its invention. Rubin goes on to say that the usage of cypher discs continued during the Civil War, with the South utilising brass cypher discs while the North consistently decrypted them for communication (2008).
Gilbert Vernam attempted to improve on the broken cypher by developing the Vernam-Vigenere cypher in 1918, but was unable to build one with much more strength. His efforts resulted in the one-time pad, which employs a keyword only once and proves to be nearly impenetrable (Rubin, 2008). Whitman claims that during prohibition, criminals communicated via cryptography.
It’s also worth mentioning the recently trendy “wind talkers.” Using their own language (2005), the Navajos developed cryptography. The code was never broken and was critical to WWII’s success in the Pacific Theater. One could argue that verbal communication language was not technically cryptography. However, it should be noted that the message was always written down as a matter of practice.
The public key cryptography approach has achieved widespread usage in modern times. Today, the use of a common public key and a private key held only by the sender is used as a form of asymmetric encryption; one use of this technique is for the sender to use the private key to encrypt the message and then anyone who gets the message to use the public key to decipher it. In this method, the receiver knows who sent the message.
This method is the foundation of the digital signature. Problems emerge when communications between several organisations necessitate the usage of multiple public keys and the knowledge of which one to use when. Whatever method is chosen, a mix of procedures performed sequentially will yield the greatest results (Whitman, 2005).
Finally, it is somewhat surprising how brief the history of this vital topic is. Without a doubt, cryptography, and more broadly, cryptology, has played a significant part in the shaping and development of many nations and cultures. While history may offer a different perspective, it is worth recalling that the winners frequently write history.
If an army had a powerful weapon that was essential in supplying information that led to victory, how likely were they to reveal it in battle records? Instead, it may appear that idolising heroes is preferable to revealing the cloak and dagger means that led to success. Cryptography, by definition, implies secrecy and deception; thus, it is not surprising that the history of this topic is brief and relatively inaccessible. Perhaps it is already coded in what has been written.