Ancient Greeks, Spartans, Romans ‘ they all practised message encryption. They would use hieroglyphics, combine several alphabets, write on pieces of leather, or build special machines for it. Nowadays, hi-tech computers handle data encryption, but in the past people had their own methods. Let us take a look at them!
Encryption helps to protect data stored on a computer or transmitted over the Internet or other networks. Sophisticated algorithms are vital to the security of IT and communication systems ‘ confidential information is incredibly valuable, so it is hardly surprising that everyone tries to protect them as well as possible. Certain companies are willing to spend huge amounts of money for data security measures. But how did it all work in the pre-computer times?
How did Julius Caesar cipher?
The word ‘encryption‘ comes from the Greek ‘kryptos‘, meaning something secret or hidden. Encrypted texts appeared as soon as 1900 BC, taking the form of hieroglyphics on Egyptian walls, intended to hide the writing‘s true meaning.
In 700 BC, the Spartans built probably the first device ever allowing to encrypt messages. How did it function? The text was written on a piece of leather wrapped around a specifically shaped piece of wood. Once unwrapped, the message was illegible, as the characters became misaligned, forming no legible sentences. Only after wrapping around a piece of wood identical to the original one, the message became understandable ‘ the leather would fold in specified places, arranging the characters in order.
Several hundred years later, the Romans used the Caesar‘s cipher, also known as the shift cipher. It is a standard alphabet, with every letter having its ciphered counterpart. It was named after Julius Caesar, who used it with a key of 3 to correspond with his associates. How does it work? Key of 3 means that every letter has its ciphered counterpart shifted by 3 consecutive letters. For instance, ‘Detective Store‘ encrypted with key of 3 would read ‘Ghwhfwlyh Vwruh‘. It might seem difficult to read at first, but it gets easier over time. Additionally, if you have the alphabet written in front of you, decrypting the message becomes trivial ‘ provided you know which key was used to encrypt it.
The Middle Ages were the era of polialphabetic ciphers, where specific characters were encrypted using different keys and alphabets. In a message encrypted this way, every letter or digit could be shifted differently! Compared to monoalphabetic encryption, polialphabetic ciphers were resistant to cryptologists‘ (specialists in message decryption) efforts for a long time. Another method worthy of mentioning is the Vigen‘re cipher, wrongly named after Blaise de Vigen‘re. It turned out that the exact same method was described earlier by Giovani Batista Belaso, and it is him that the cipher should be named after. This method is an excellent example of the polialphabetic cipher. It is also similar to the method used by Julius Caesar ‘ every letter has its ciphered counterpart. However, Caesar used two alphabets only ‘ the basic one, and another, shifted by a specified number. Belaso expanded the cipher by adding a few more alphabets. Additionally, reading the message required a key word, determining how the ciphered characters should be read. If the key word is shorter than the message itself, it is repeated required number of times.
For instance ‘ the message we want to encrypt is ‘Spy Shop‘, key word is ‘hack‘:
Spy Shop (message)
hac khac (hack ‘ repeated key word)
Encryption result is ZPA COOR
How does it happen?
First row of the table below corresponds with the letters of out message ‘ ‘ Spy Shop‘ ‘ while the first column corresponds with the letters of the key word ‘hack‘. Now, simply collate the letters of the message and key word with each other(e.g. S with H) and see what spot on the table they point to. The table displays encrypted word ‘Spy‘.
Also in the Middle Ages, first attempts were made to build machines simplifying the encryption process. They consisted of several cogs, dials and various other elements. Many of these attempts failed, but in the same period a working machine, consisting of two dials, was constructed by Leon Battista Alberti ‘ an Italian painter, poet and cartographer.
Possibly the most well-known device utilising polialphabetic encryption was the world-famous Enigma, used by the Germans during II World War, and ultimately deciphered with the help of Polish cryptologists. Apart from it, the Lorenz cipher is also an example worth mentioning. Both devices are considered milestones in the history of data encryption.
During the times when literacy was far from being common, there was little need for ciphering messages, but that situation changed quickly over time. In order to hide the message‘s true meaning, regular writing would be replaced with different signs, symbols, numbers or pictures, meaningful only to a person possessing the proper key. The methods of obscuring the messages have changed throughout the ages. Nowadays, due to computer technology, it looks completely different than in the past. How is data encrypted today? Find out in the next article!