Editing Zero-knowledge proof (section)

=== Authentication systems ===
Research in zero-knowledge proofs has been motivated by [[authentication]] systems where one party wants to prove its identity to a second party via some secret information (such as a password) but does not want the second party to learn anything about this secret. This is called a "zero-knowledge [[proof of knowledge]]". However, a password is typically too small or insufficiently random to be used in many schemes for zero-knowledge proofs of knowledge. A [[zero-knowledge password proof]] is a special kind of zero-knowledge proof of knowledge that addresses the limited size of passwords.{{citation needed|date=June 2021}}

In April 2015, the one-out-of-many proofs protocol (a [[Proof of knowledge#Sigma protocols|Sigma protocol]]) was introduced.<ref name=":1" /> In August 2021, [[Cloudflare]], an American web infrastructure and security company, decided to use the one-out-of-many proofs mechanism for private web verification using vendor hardware.<ref>{{Cite web|date=2021-08-12|title=Introducing Zero-Knowledge Proofs for Private Web attestation with Cross/Multi-Vendor Hardware|url=https://blog.cloudflare.com/introducing-zero-knowledge-proofs-for-private-web-attestation-with-cross-multi-vendor-hardware/|access-date=2021-08-18|website=The Cloudflare Blog|language=en}}</ref>