Encryption is a technique used in cryptography to encode data, essentially transforming data that can be read into unintelligible data. And although modern encryption techniques are heavily based on mathematical theory, computer science and even physics, early encryption was far less sophisticated.

The Caeser Cipher

In fact, one of the oldest and well-documented forms of encryption, the Caesar Cipher, is believed to have been used by the Roman Army, as well as by Julius Caesar, for the encryption of military, official and private communications. But how does it work?

The Caesar Cipher works by shifting each letter of a message forward a specific number of places in the alphabet. To read the message you need to know how many places each letter was moved (this is called the key) For example with a shift of 1, A would be replaced by B, B would become C, and so on.

So, if we were to apply the same Caeser Cipher shift of 1 to this paragraph...

"Julius Caser born 12 July 100 BCE (though some cite 102 as his birth year). His father, also Gaius Julius Caeser, was a Praetor who governed the province of Asia and his mother, Aurelia Cotta, was of noble birth"

...the resulting ciphertext would look as follows...

"Kvmjvt Dbtfs cpso 12 Kvmz 100 CDF (uipvhi tpnf djuf 102 bt ijt cjsui zfbs). Ijt gbuifs, bmtp Hbjvt Kvmjvt Dbftfs, xbt b Qsbfups xip hpwfsofe uif qspwjodf pg Btjb boe ijt npuifs, Bvsfmjb Dpuub, xbt pg opcmf cjsui"

Simplistic in nature the effectiveness of the Caeser Cipher could, in part, be attributed to the fact that much of the world, including Rome’s enemies, were illiterate at the time.

Modern Encryption

However just as civilisations have evolved over the centuries, so to has encryption. In today's modern world, there are two forms of encryption that are widely used in cryptography, symmetric and asymmetric, each of which we’ll explore in upcoming articles.

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