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Table 1 Glossary of blockchain and distributed ledger technology terms [1, 3, 9]

From: Geospatial blockchain: promises, challenges, and scenarios in health and healthcare

Bitcoin Cryptocurrency created by the person(s) named Satoshi Nakamoto in 2009. Introduced proof of work consensus for addressing the potential issue of double-spending of digital currency without a centralised form of authentication
Blockchain A form of DLT where blocks of data are added sequentially and linked together with representative hash values
Ciphertext Information (text) that has been encrypted (made unreadable) using an algorithm known as a cipher. This information can only be used if the appropriate cipher key is possessed
Consensus Algorithms An algorithm or protocol used to find consensus, or agreement, among multiple distributed nodes. Consensus allows nodes to agree on updates to the blockchain itself. Examples include Proof of Work and Proof of Stake
DApps Decentralised Applications (DApps) are applications written on the Ethereum blockchain with similar properties to a blockchain. They run on a decentralised network and remove the need for trust in any one agency. Contributions in computation to keep a DApp running pay out in a similar manner to contributions to blockchain nodes
Distributed Ledger Technology (DLT) A database shared through consensus and spread among multiple sites, or nodes, and lacking centralised data storage
Ethereum A blockchain alternative to the Bitcoin blockchain that introduces Smart Contracts, or scripting, and decentralised applications (DApps) by building in a Turing-complete programming language on top of the Ethereum blockchain
Fork A split in the blockchain that could be caused by consensus protocol change (difference of opinion within community) or mining a different version of an existing block (attack) as examples. Forks can lead to small branches on the blockchain that are quickly abandoned or to new blockchains with their own supporters (Ethereum and Ethereum Classic)
Node A device participating in the blockchain network. A blockchain network is comprised of distributed nodes each with their own copy of the blockchain’s information
Nonce A random value used once to ensure the correct hash value is set during blockchain mining. This value is being mined to satisfy Proof of Work consensus
Smart Contracts Programs or scripts written on the Ethereum blockchain that execute if a given set of specific requirements are met and that require no governing body to ensure their “payouts” are met properly