A blockchain is a growing list of records, called blocks, that are linked together using cryptography. Each block contains a cryptographic hash of the previous block, a timestamp, and transaction data. The timestamp proves that the transaction data existed when the block was published in order to get into its hash. As blocks each contain information about the block previous to it, they form a chain, with each additional block reinforcing the ones before it. Therefore, blockchains are resistant to modification of their data because once recorded, the data in any given block cannot be altered retroactively without altering all subsequent blocks.
Blockchains are typically managed by a peer-to-peer network for use as a publicly distributed ledger, where nodes collectively adhere to a protocol to communicate and validate new blocks.
Ethereum is a decentralized, open-source blockchain with smart contract functionality. Ether (ETH or Ξ) is the native cryptocurrency of the platform. Amongst cryptocurrencies, Ether is second only to Bitcoin in market capitalization.
Ethereum was conceived in 2013 by programmer Vitalik Buterin.Web3, also known as Web 3.0, is a new iteration of the Internet that is based on public blockchains. The term was coined in 2014 by Ethereum co-founder Gavin Wood, and the idea gained interest in 2020 and 2021 from cryptocurrency enthusiasts, large technology companies, and venture capitalist firms.
A non-fungible token (NFT) is a unique and non-interchangeable unit of data stored on a digital ledger (blockchain). NFTs can be associated with reproducible digital files such as photos, videos, and audio. NFTs use a digital ledger to provide a public certificate of authenticity or proof of ownership, but it does not restrict the sharing or copying of the underlying digital file. The lack of interchangeability (fungibility) distinguishes NFTs from blockchain cryptocurrencies, such as Bitcoin.
NFTs have drawn criticism with respect to the energy cost and carbon footprint associated with validating blockchain transactions as well as their frequent use in art scams. Further criticisms challenge the usefulness of establishing proof of ownership in an often extralegal unregulated market.