A blockchain is a decentralized, distributed digital ledger that is used to record transactions across many computers so that the record cannot be altered retroactively without the alteration of all subsequent blocks and the consensus of the network.
Blockchains are designed to be resistant to modification of the data. A blockchain is a continuously growing list of records, called blocks, which are linked and secured using cryptography. Each block typically contains a cryptographic hash of the previous block, a timestamp, and transaction data. By design, a blockchain is resistant to modification of the data.
Blockchains are used in a variety of applications, such as tracking ownership or the provenance of documents, digital assets, physical assets, or voting systems. Some popular examples of blockchain technology include <a href="/prices/bitcoin">Bitcoin</a>, <a href="/prices/ethereum">Ethereum</a>, and <a href="/prices/litecoin">Litecoin</a>.