A blockchain is a ledger of blocks of information (e.g., transactions and agreements) stored sequentially across a network of computers. Rather than a simple algorithm, blockchain is a technology construct and an enabling protocol that facilitates a decentralized brokering of data among participants: that is, its revolutionary properties do not derive from what blockchains do (i.e., store data securely) but from how they are used and implemented (i.e., trustless and decentralized). Just as the Transmission Control Protocol and Internet Protocol (TCP/IP), invented in the 1970s at DARPA (Held The ABCs of TCP/IP, Auerbach, 2003), enabled the decentralized exchange of information (i.e., the Internet), blockchains enable the decentralized control of the transfer of assets. Indeed, the innovation with blockchain does not derive from a fundamentally new technology approach, but from the application of well-established information technology methods (e.g., cryptographic hashing, asymmetric encryption, and peer-to-peer network architecture) to the problem of information transfer.