Blockchain, the technology behind cryptocurrencies, is "one of the most overhyped technologies ever," according to noted economist Nouriel Roubini.
Bitcoin was one of the first applications of the blockchain. It's a public ledger of bitcoin transactions that is tamperproof. Transactions on the bitcoin blockchain require verification from a number of different parties. The transactions are verified by so-called "miners" solving complex mathematical puzzles with high-powered computers.
There is no central authority on the bitcoin network which is why the blockchain is often called distributed ledger technology. Large financial institutions are exploring how it could be used.
Advocates have said that it could speed up processes such as legal contracts, cross-border money movement, and back-end processes in large firms.