From the Summary: "Blockchain, generally, is a database technology that records and stores information in blocks of data that are linked, or 'chained,' together. Data stored on a blockchain are continually shared, replicated, and synchronized across the nodes in a network--individual computer systems or specialized hardware that communicate with each other and store and process information. This system enables tamper-resistant recordkeeping without a centralized authority or intermediary. There are multiple types of blockchains, and, depending on the type, recorded data may be accessible to all users or only a designated subset. All blockchains share common characteristics, including decentralization (i.e., no centralized authority), immutability (i.e., the blockchain records are unalterable), and pseudonymity (i.e., how users' real-world identities are handled). Certain blockchain types may offer greater levels of decentralization and pseudonymity than others. New blockchain applications, such as smart contracts, non-fungible tokens, and decentralization autonomous organizations, may automate processes or replace intermediaries in a variety of fields. Recent developments in blockchain governance protocols and consensus mechanisms have raised concerns about the environmental impact, oversight, and accountability of blockchain networks."
CRS Report for Congress, R47064
Congressional Research Service: https://crsreports.congress.gov/