Chainlink (blockchain oracle)
{{Short description|Cryptocurrency and Ethereum token}}
{{Infobox cryptocurrency
| currency_name = Chainlink
| image_1 = Chainlink Logo Blue.svg
| image_2 =
| image_title_1 =
| plural = Chainlink
| symbol =
| ticker_symbol = LINK
| previous_names =
| precision =
| white_paper = {{URL|https://chain.link/whitepaper}}
| implementations =
| initial_release_version =
| initial_release_date =
| code_repository = {{URL|https://github.com/smartcontractkit/chainlink}}
| status =
| latest_release_version =
| latest_release_date =
| project_fork_of =
| programming_languages = Solidity, Go
| operating_system = Blockchain-agnostic
| author = Sergey Nazarov, Steve Ellis, Ari Juels{{cite web |url=https://link.smartcontract.com/whitepaper |last1=Ellis |first1=Steven |last2=Juels|first2=Ari|last3=Nazarov|first3=Sergey |date=4 September 2017 |website=chain.link |language=English |title=ChainLink A Decentralized Oracle Network|format=paper|access-date=8 October 2022 |url-status=dead |archive-url=https://web.archive.org/web/20171006080308/https://link.smartcontract.com/whitepaper |archive-date=6 October 2017 }}{{Cite journal|last=Caldarelli|first=Giulio|date=November 2020|title=Understanding the Blockchain Oracle Problem: A Call for Action|journal=Information|publisher=MDPI|language=en|location=Verona, Italy|volume=11|issue=11|pages=509|doi=10.3390/info11110509|doi-access=free}}
| developer =
| source_model = Open source
| license = MIT License
| block_explorer =
| ledger_start =
| split_date =
| split_from =
| hash_function =
| issuance_schedule =
| timestamping =
| merged_mining_parent =
| block_time =
| block_reward =
| circulating_supply =
| supply_limit = 1,000,000,000
| exchange_rate =
| market_cap =
| website = {{URL|https://chainlinklabs.com}}
}}
Chainlink is a decentralized blockchain oracle network. Chainlink's token was originally deployed on Ethereum and has since been deployed to other blockchains that offer Chainlink services.{{cite web |url=https://research.chain.link/whitepaper-v2.pdf |title=Chainlink 2.0. The Next Steps in the Evolution of Decentralized Oracle Networks 9 Economics and Cryptoeconomics Staking |last1=Breidenbach |first1=Lorenz |last2=Chacin |first2=Christian |last3=Chan |first3=Benedict|last4=Coventry |first4=Alex|last5=Ellis |first5=Steven |last6=Juels |first6=Ari |last7=Koushanfar |first7=Farinaz|author-link7=Farinaz Koushanfar |last8=Miller |first8=Andrew |last9=Magauran |first9=Brendan |last10=Moroz |first10=Daniel |last11=Nazarov |first11=Sergey |last12=Topliceanu|first12=Alexandru |last13=Tramèr |first13=Florian |last14=Zhang |first14=Fan |date=15 April 2021 |orig-year=2017|website=chain.link |series= |publisher= |agency=research.chain.link |location=University of Bern, Cornell Tech, University of California, University of Illinois Urbana-Champaign, Duke University |pages=2, 78 |language=English|format=paper |access-date=4 July 2021 |url-status=live |archive-url=https://web.archive.org/web/20210415141430/https://research.chain.link/whitepaper-v2.pdf |archive-date=2021-04-15}}{{Cite web|last=Anadiotis|first=George|title=Chainlink launches Mainnet to get data in and out of Ethereum smart contracts|url=https://www.zdnet.com/finance/blockchain/chainlink-launches-mainnet-to-get-data-in-and-out-of-ethereum-smart-contracts/|access-date=2021-08-29|website=ZDNet|language=en}}{{Cite web|title=LINK Token Contracts|url=https://docs.chain.link/resources/link-token-contracts}} The network is intended to be used to facilitate the transfer of tamper-proof data from off-chain sources to on-chain smart contracts.{{cite book |last1=Nikbakht |first1=Ehsan |last2=Baker |first2=H Kent |last3=Smith |first3=Sean Stein |title=The Emerald Handbook of Blockchain for Business |date=9 March 2021 |publisher=Emerald Publishing Limited |isbn=9781839821981 |url=https://books.google.com/books?id=jKYgEAAAQBAJ&dq=chainlink+blockchain&pg=PA182 |access-date=8 March 2022}} As of November 2021, Chainlink oracles had secured $75 billion in total value across decentralized finance applications.{{Cite news |last=Akhtar |first=Tanzeel |date=March 29, 2022 |title=Chainlink Labs Taps Former Diem CTO Dahlia Malkhi in Web3 Push |url=https://www.bloomberg.com/news/articles/2022-03-29/chainlink-labs-taps-former-diem-cto-dahlia-malkhi-in-web3-push |access-date=2025-07-01 |work=Bloomberg}}
History
Chainlink was created in 2017 by Sergey Nazarov and Steve Ellis,{{cite web |last1=Anadiotis |first1=George |title=Chainlink launches Mainnet to get data in and out of Ethereum smart contracts |url=https://www.zdnet.com/finance/blockchain/chainlink-launches-mainnet-to-get-data-in-and-out-of-ethereum-smart-contracts/ |website=ZDNet |access-date=August 3, 2021 |language=en |date=May 30, 2019}} who co-authored a white paper introducing the Chainlink protocol and network with Cornell University professor Ari Juels the same year. Chainlink acts as a "bridge" between a blockchain and off-chain environments.{{cite news |last1=Arrowsmith |first1=Ranica |title=Tech, accelerated; 2020 was a hothouse for technology, speeding up the already rapid pace of development and adoption |work=Accounting Today |issue=34 |date=December 1, 2020 |page=30}} The network, which services smart contracts, was formally launched in 2019.
In 2018, Chainlink integrated Town Crier, a trusted execution environment-based blockchain oracle that Juels also worked on. Town Crier connects the Ethereum blockchain with web sources that use HTTPS.{{cite web |last1=Orcutt |first1=Mike |title=Blockchain smart contracts are finally good for something in the real world |url=https://www.technologyreview.com/2018/11/19/139032/blockchain-smart-contracts-can-finally-have-a-real-world-impact/ |website=MIT Technology Review |access-date=August 3, 2021 |language=en |date=November 19, 2018}}
In 2020, Chainlink integrated DECO, a Cornell project co-created by Juels. DECO is described by its authors as a protocol that uses zero-knowledge proofs to allow users to prove information is true to a blockchain oracle without revealing sensitive information, such as birth dates.{{cite web |last1=Brett |first1=Charles |title=Chainlink acquires DECO from Cornell |url=https://www.enterprisetimes.co.uk/2020/09/04/chainlink-acquires-deco-from-cornell/ |website=Enterprise Times |access-date=August 3, 2021 |date=September 4, 2020}}
Chainlink published a second white paper in April 2021. That paper, Chainlink 2.0: Next Steps in the Evolution of Decentralized Oracle Networks, detailed a vision for expanding the role and capabilities of decentralized oracle networks to include hybrid smart contracts, which utilize on-chain code and off-chain services provided by oracle networks.{{cite web |last1=Anadiotis |first1=George |title=Chainlink 2.0 brings off-chain compute to blockchain oracles, promotes adoption of hybrid smart contracts |url=https://www.zdnet.com/finance/blockchain/chainlink-2-0-brings-off-chain-compute-to-blockchain-oracles-promotes-adoption-of-hybrid-smart-contracts/ |website=ZDNet |access-date=July 27, 2021 |language=en |date=April 15, 2021}}
Technology
File:SIBOS17 – Chainlink - cleaned.png
Chainlink's decentralized oracle network is an open-source technology infrastructure that allows any blockchain to securely connect to off-chain data and computation resources. The network nodes fetch, validate, and deliver data from multiple sources onto blockchains to execute smart contracts.{{cite web|last1=Anadiotis|first1=George|date=May 30, 2019|title=Chainlink launches Mainnet to get data in and out of Ethereum smart contracts|url=https://www.zdnet.com/finance/blockchain/chainlink-launches-mainnet-to-get-data-in-and-out-of-ethereum-smart-contracts/|access-date=July 27, 2021|website=ZDNet|language=en}}
In addition to the transfer of external information to a blockchain, Chainlink can also be used for several different off-chain computation functions, including a verifiable random function (VRF) and data feeds. The data feeds have been used to bring election data on-chain.{{cite web|last1=Castillo|first1=Michael del|date=November 3, 2020|title=How To Track Official Election Results On Ethereum And EOS|url=https://www.forbes.com/sites/michaeldelcastillo/2020/11/03/how-to-track-official-election-results-on-ethereum-and-eos/?sh=631ebb013269|access-date=July 26, 2021|website=Forbes|language=en}}
Chainlink's VRF can be used for random number generation which can be used in decentralized gaming. ZDNet reported the verifiability of the random number generation ensures the in-game results are tamper-proof.{{cite web|last1=Brown|first1=Eileen|date=November 10, 2020|title=Chainlink VRF makes blockchain games more trustworthy by using verifiable on-chain source of randomness|url=https://www.zdnet.com/finance/blockchain/chainlink-vrf-makes-blockchain-games-more-trustworthy-by-using-verifiable-on-chain-source-of-randomness/|access-date=August 3, 2021|website=ZDNet|language=en}}
Link token
Node operators are compensated with the network's native cryptocurrency, LINK. Chainlink's LINK token is an ERC677 token, an extension of ERC-20. All LINK tokens have been premined and largely withheld by the central issuer. A fraction of the pre-mined token supply was offered for sale to retail buyers in an initial coin offering (ICO){{fact|date=November 2024}}.
Tokens act as data payloads, feeding the required data from off-chain sources to smart contracts, which then act accordingly in response to the data provided by the token.{{cite web |last1=Prathap |first1=Madana |title=Looking beyond Bitcoin and Ethereum — Here's a list of top 15 altcoins you should keep an eye on |url=https://www.businessinsider.in/investment/news/top-15-best-altcoins-to-buy-in-2021/slidelist/87717381.cms#slideid=87718438 |website=Business Insider India}} According to Chainlink, the trade value derived from these tokens is used to pay node operators for retrieving data from smart contracts, and also for deposits placed by node operators as required by contract creators. Tokens can be stored in any ERC-20 wallet, as the ERC677 token retains all the functionality of an ERC-20 token.{{Cite web|title=FAQ {{!}} Chainlink Documentation|url=https://docs.chain.link/docs/faq/#:~:text=The%20LINK%20token%20is%20an,as%20required%20by%20contract%20creators.|access-date=2021-07-24|website=docs.chain.link}}{{cite book |title=Financial Cryptography and Data Security. FC 2021 International Workshops |date=16 September 2021 |publisher=Springer Berlin Heidelberg |isbn=9783662639580 |url=https://books.google.com/books?id=nI5DEAAAQBAJ&dq=chainlink+token+ERC677&pg=PA116}}
References
{{reflist}}
{{Cryptocurrencies}}