Blockchain is the underlying technology that is behind most major cryptocurrencies. A blockchain is essentially a decentralized ledger that records all transactions as well as other information and is shared among all users. E.g., the Bitcoin blockchain contains a record of every Bitcoin transaction that has ever been completed. Blockchain technology goes beyond payment applications and has lots of potential uses that have piqued the interest of many major corporations. For example, blockchain could theoretically be used to keep a record of real estate transactions, execute contracts with Ethereum, among many other things.