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Hash Function

A one-way function that turns any input into a fixed-size fingerprint, used to chain blocks and detect tampering.

FBFenwei BianAuthorVZVictor ZhouEditorJuly 2, 2026
  • glossary

A hash function (also called a cryptographic hash function) takes an input of any size and deterministically produces a fixed-size output, or digest, such that changing even one bit of the input scrambles the output completely and finding two inputs with the same digest is computationally infeasible. Bitcoin chains its blocks by embedding the double SHA-256 hash of each block header inside the next one, so altering any past block would change its hash and break every block after it. Ethereum uses a related function, Keccak-256, to derive account addresses from public keys and to build its Merkle trees. This tamper-evidence is also what underpins cryptographic security for a tokenized domain: the NFT representing ownership is committed into the same hash-secured chain state as every other on-chain asset.

Related keywords

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  • SHA-256
  • Keccak-256
  • hashing
  • collision resistance
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Contributors

Fenwei Bian

Software Developer & Writer • Namefi
Author

Fenwei Bian is a software developer in her thirties who spends her working hours in pull requests and her weekends with her hands in soil or sawdust. Years of open source on GitHub taught her that names are interfaces: a good one is clear, honest about what it does, and kind to whoever has to use it next.

She gardens because it rewards patience and punishes wishful thinking, and she does woodwork because a joint either fits or it doesn't. Both habits show up in how she writes about naming — measure twice, check the source, and don't sand over a rough spot and hope no one notices.

For Namefi she writes about how domain markets actually move, the practical trade-offs of tokenizing and flipping names, and picking a domain you'll still be glad you own in twenty years.

GitHub

Victor Zhou

Founder & Standards Editor • Namefi
Editor

Victor Zhou is a technology founder and standards editor focused on digital identity and trust. He founded Namefi, edits Ethereum Improvement Proposals, and previously led smart-contract architecture work at Google Labs.

His work sits at the intersection of naming, ownership, and the systems people use to establish identity online. That perspective makes him especially interested in the way names move between personal meaning, public recognition, and digital infrastructure.

For Namefi, Victor edits and writes about domains as durable digital identity: how names become ownable onchain assets, how tokenization changes custody and trust, and what naming can learn from the systems people use to establish identity online.

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