Cryptography

Alright then, so cryptography. Cryptography is essentially the concept of secret codes, but developed to a certain point. Modern cryptography is heavily based on mathematical theory and computer science, and cryptographic algorithms are designed to be difficult to break by any opponent. Cryptography allows people to protect their information and keep it safe from potential hackers, and is invaluable for the big-tech companies of today.

Cryptography includes techniques such as microdots, merging words with images, and other ways to hide information. Today, cryptography is mainly associated with scrambling “plaintext” (just regular text) into “ciphertext”. This process is known as “encryption”, where in the text is made into secret code that can be then “decrypted” back into plain text after the data is transported to where it needs to be.

Think of cryptography as essentially a cipher, like the coded messages sent by Julius Caesar to his allies. Only a select few people with the right key to decode the cipher will be able to read the text.

The most common and well-known method of cryptography is “public and private key” encryption done in the RSA (Rivest-Shamir-Adleman) method. This is very common over the internet, where encryption is very much necessary. Public key cryptography uses two different but mathematically similar keys, being the private key and the public key. The public key is, well, public. Anyone can see it and use it, but the private key is to remain just with you.

This public-private encryption can be simplified to a simple exchange. Say your friend wants to send you some old, embarrassing pictures. Now you have a safe that you keep empty and you realize that you can use it to keep the pictures in, so that no nosy family member can take your precious memories. But what if someone takes them while you are bringing the pictures over? You decide you can send the safe to your friend so that they can put in the pictures, and thus bring them over safely. However, you can’t trust your friend with a key to the safes’ padlock, as their siblings are very annoying and could steal it. So, what can you do?

A simple way to do it is for you to send the open, empty safe that anyone can access (the metaphorical public key) to your friend. As the safe is empty, no one will want to take it. Your friend can then put in the pictures and close down the padlock. This way, no one at their house can open it as they only have a safe and not the key. Your friend then sends the safe back, and you can use the key that you have (your metaphorical private key) to open it and secure the pictures.

Either way, the data that you transferred is now secure (in one way), and your embarrassing moments are long forgotten.

If you want to learn more about cryptography, check out this video by MIT OpenCourseWare detailing the RSA method. And if you want to learn about how quantum computers can break the public key encryption method, check out this video here by Frame of Essence. Next week we will look at everyone’s favorite, bitcoin and blockchain. Until then, good luck.