What is a zero-knowledge proof?
A zero-knowledge proof can show that a statement is true without exposing the private information used to prove it.
Version 1
GlossaryA zero-knowledge proof lets someone check a statement without seeing the private information behind it.
Imagine proving you are old enough for an age-restricted service without showing your full birthday. That illustrates the goal, not a claim that every identity app works this way.
A little more technical
Software defines a statement and its rules. A prover creates evidence from private inputs, and a verifier checks it. The proof can hide those inputs while still letting the verifier check the specified claim.
Common misunderstanding
A valid proof does not prove that an entire product is safe. It proves the statement encoded by its rules, subject to the system’s security assumptions. Bad rules, software bugs or information exposed elsewhere can still create problems.