# zero-knowledge-proof

Source: https://startwithidentity.com/glossary/zero-knowledge-proof/
Last updated: 2026-08-29
License: content by Start with Identity. Cite the source URL.

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A cryptographic technique that proves a statement is true without revealing the underlying data, for example proving you are over 18 without disclosing your birth date. In decentralized identity it enables privacy-preserving credential presentation beyond simple selective disclosure.

ZKPs are the strongest available privacy tool in credentials, letting a holder prove a predicate (over 18, resident of this country, income above a threshold) without revealing the underlying value or being correlatable across presentations. Adoption is limited less by the cryptography than by tooling and verifier support, which is why simpler hash-based selective disclosure shipped first in national programs.

See also: [selective disclosure](https://startwithidentity.com/glossary/selective-disclosure/), [BBS signature](https://startwithidentity.com/glossary/bbs-signature/), [AnonCreds](https://startwithidentity.com/glossary/anoncreds/), [verifiable credentials](https://startwithidentity.com/standards/verifiable-credentials/)