Cryptography has been around for thousands of years and is at the heart of digital communications today. Most people rely on cryptography on a daily basis without even knowing it; most popular messaging apps use encryption to ensure the security of messaging between two people. Blockchain technology, in a similar way, relies on cryptography to protect the identity of those sending and receiving messages and ensures that all information and transactions are secure and legitimate. Thus, to really understand blockchain technology, you have to understand the core principles of cryptography.

This course will walk you through the basics of cryptography: how information has historically been disguised (encrypted) and revealed (decrypted) using mathematics. You will see how a message can be turned into a number, and how that number can be encrypted and decrypted by two complete strangers. You will practice encrypting your own message to understand the basics of what makes a good encryption scheme. Then, you will delve deeper into the specific type of cryptography used in blockchain technology -- public key cryptography - and the promises and limitations it has in carrying out the core functions of a blockchain. You will create your own theoretical gold exchange in order to more fully understand how you can send anything to anyone around the world without a middleman. Ultimately you will know exactly how information on the blockchain is secured, legitimized, and authenticated without needing a third party to verify it.