Cryptography

Written by Aimee Matthews

Cryptography has existed for millennia and you yourself probably tried your hand at it before you even knew what it was. I remember as a kid watching films from my grandfather’s James Bond collection and fancying myself as a spy. I would send encrypted messages to my friends, written in lemon juice to make them doubly secret so the messages would only reveal themselves when exposed to heat. Our system normally consisted of using numbers 1 to 26 to represent the letter’s place in the alphabet. Not a very sophisticated system, I know, but what can you expect from ten-year-olds? 

The word cryptography comes from the Greek ‘kryptos graphien’ or ‘hidden writing’ and is the science of using code to encrypt messages. Until recent history, it has taken the form of classic cryptography, methods that rely on pen and paper. It can be traced back as early as Egypt around 1900 BC, where it is believed cryptography originated. Disordered hieroglyphs were found in the main chamber of the tomb of Khnumhotep II, encrypted using a substitution cypher, where each letter of the plaintext is substituted for another letter of the alphabet. Substitution cyphers are still used today, although they don’t always have to use letters. They can use numbers or even symbols, such as the lines and dots we see in morse code. Some forms of classic cryptography also used primitive devices. An early example is the scytale, used by the Spartans in Circa 600 BC, consisting of a message written on a leather strap which would only make sense when wrapped around a wooden pole of a specific size. If it was too large or too small, the message would not make sense to the reader, nor would it make sense if the strap was unravelled. 

While they might be confusing at first glance, classic ciphers are usually fairly easy to decode and simply wouldn’t cut the mustard protecting peoples’ information in today’s society. With the advance of technology and the invention of more sophisticated machinery (such as Arthur Scherbius’ Enigma rotor machine) what we now call strong cryptography came into being, a system where mathematical algorithms are key in encrypting and decrypting information. Today, encryption keeps your data safe while you are online, scrambling things such as your contact details and credit card information so cyber criminals can’t steal it. It also plays a part in cryptocurrency. Since it is a virtual currency, it is secured by cryptography, meaning that it is nearly impossible for it to be counterfeited. In fact, Blockchain is a revolution in cryptography that uses the power of decentralisation, which guarantees autonomy from a central authority. While the World Bank and the Pentagon are successfully hacked every day, the original Bitcoin blockchain has never once been successfully hacked since it was first established in 2009, undeniably lending it credibility as an alternative to conventional currencies.