> ## Documentation Index
> Fetch the complete documentation index at: https://docs.theblockchainlibrary.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Witness

> Private or auxiliary information known to a prover and used to demonstrate that a zero-knowledge statement is true.

# Witness

Private or auxiliary information known to a prover and used to demonstrate that a zero-knowledge statement is true.

## Definition

Private or auxiliary information known to a prover and used to demonstrate that a zero-knowledge statement is true.

## Why it matters

Zero-knowledge systems enable verification of claims or computation while minimizing disclosure of underlying information.

## Related knowledge

* [Cryptography](/categories/cryptography) — term
* [Prover](/generated/v2/glossary/prover) — term
* [Verifier](/generated/v2/glossary/verifier) — term
* [Zero-Knowledge Proof](/generated/v2/glossary/zero-knowledge-proof) — term

***

**Canonical knowledge ID:** `glossary:witness`