Bitcoin is a network that runs on a protocol known as the blockchain. A 2008 paper by a person or people calling themselves Satoshi Nakamoto first described both the blockchain and Bitcoin and for a while the two terms were all but synonymous.

The blockchain​ has since evolved into a separate concept, and thousands of blockchains have been created using similar cryptographic techniques. This history can make the nomenclature confusing. Blockchain sometimes refers to the original, Bitcoin blockchain. At other times it refers to blockchain technology in general, or to any other specific blockchain, such as the one that powers Ethereum​.

The basics of blockchain technology are mercifully straightforward. Any given blockchain consists of a single chain of discrete blocks of information, arranged chronologically. In principle this information can be any string of 1s and 0s, meaning it could include emails, contracts, land titles, marriage certificates, or bond trades. In theory, any type of contract between two parties can be established on a blockchain as long as both parties agree on the contract. This takes away any need for a third party to be involved in any contract. This opens a world of possibilities including peer-to-peer financial products, like loans or decentralized savings and checking accounts, where banks or any intermediary is irrelevant.