Ari Juels
American Cryptographer
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Ari Juels is an American Cryptographer. As of 2025[update], he is currently the Weill Family Foundation and Joan and Sanford I. Weill Professor at Cornell Tech and the co-director at the Initiative for CryptoCurrencies and Contracts.[1]
Client puzzles
Blockchain oracles (Town Crier, DECO)
Maximal extractable value
Proofs of retrievability
Fuzzy cryptography
Chainlink Labs
IC3
Ari Juels | |
|---|---|
| Alma mater | University of California, Berkeley (PhD, 1996) |
| Known for | Proof of work Client puzzles Blockchain oracles (Town Crier, DECO) Maximal extractable value Proofs of retrievability Fuzzy cryptography |
| Scientific career | |
| Fields | Cryptography Blockchain Information security |
| Institutions | Cornell Tech Chainlink Labs IC3 |
| Website | arijuels |
He is also the chief scientist at Chainlink Labs.[2] He co-authored the first Chainlink white paper in 2017 with Sergey Nazarov and Steve Ellis.[3] The smallest denomination of the LINK token, the Juel, is named in his honor.[4]
Juels was an employee of RSA Security from 1996 until 2013, with the title Chief Scientist starting in 2007.[5]
On January 20, 2022, he testified before the United States House Energy Subcommittee on Oversight and Investigations regarding the Environmental impact of the cryptocurrency industry.[1]
His best known co-authored results in cryptography and information security include:
- Proof of work (1999): Coined and formalized the term in work that predated and influenced its later use by Satoshi Nakamoto in the Bitcoin whitepaper.[6]
- Client puzzles (1999): Developed proof-of-work-based countermeasures against denial-of-service attacks that are widely used today.[7][8]
- Fuzzy cryptography (1999, 2006): Co-developed error-tolerant cryptographic primitives—fuzzy commitment schemes and fuzzy vaults—for securing noisy data such as biometric templates.[9][10]
- Privacy-preserving targeted advertising (2001): Proposed the first protocols for targeted advertising that preserve user privacy.[11]
- Coercion-resistant voting (2005): Introduced the concept of coercion-resistance, which has become a standard security property for electronic voting systems designed to resist bribery and voter coercion.[12]
- Social recovery (2006): Introduced social recovery mechanisms for credential restoration using trusted social connections, sometimes called "fourth-factor authentication."[13]
- RFID and NFC security (2003–2009): Developed security technologies for RFID and NFC tags, including the "blocker tag" privacy-protection mechanism[14] and soft blocking techniques,[15] as well as an influential survey paper on RFID security and privacy.[16]
- Proofs of retrievability (PoRs) (2007): Introduced the first efficient cryptographic technique for verifying the complete availability and integrity of remotely stored files in cloud storage systems.[17]
- Blockchain oracles (2016, 2020): Developed Town Crier, the first blockchain oracle system using trusted execution environments,[18] and DECO, a cryptographic oracle protocol.[19] Both privacy-preserving systems have been deployed by Chainlink.[20][21]
- Model-extraction attacks (2016): Introduced the concept of adversarial attacks that steal machine learning models through strategic queries.[22]
- Maximal extractable value (2020): Coined the term "miner extractable value" (MEV, later generalized to "maximal extractable value") and initiated its systematic study, contributing to the foundation of what has become a significant market in blockchain systems.[23]
Juels has published two thriller novels: Tetraktys (2009), a cryptography thriller,[24] and The Oracle (2024), a cryptocurrency and blockchain thriller.[25][26][27][28]
