> ## 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 Data

> Auxiliary proof data supplied to help a verifier confirm a transaction or state transition without holding all underlying state.

# Witness Data

Auxiliary proof data supplied to help a verifier confirm a transaction or state transition without holding all underlying state.

## Definition

Auxiliary proof data supplied to help a verifier confirm a transaction or state transition without holding all underlying state.

## Why it matters

Data concepts explain how blockchain state and proofs are represented and verified.

## Related knowledge

* [Blockchain](/categories/blockchain) — term
* [Cryptography](/categories/cryptography) — term
* [Web3](/categories/web3) — term

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