> ## 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.

# Byzantine Fault Tolerance

> The ability of a distributed system to reach agreement even when some participants fail or behave maliciously.

# Byzantine Fault Tolerance

The ability of a distributed system to reach agreement even when some participants fail or behave maliciously.

## Definition

The ability of a distributed system to reach agreement even when some participants fail or behave maliciously.

## Why it matters

Consensus concepts explain how independent nodes agree on one shared history without a central coordinator.

## How it works

The system uses multi-round voting mechanisms to reach agreement. Nodes exchange cryptographically signed messages about the validity of data. A block is only added if a predefined supermajority of nodes confirm they have seen and validated the same data, effectively ignoring the dishonest minority.

## Real-world example

The Cosmos SDK and Tendermint Core are prominent modern examples of BFT-based consensus frameworks in production.

## Advantages

* Resilience against arbitrary node behavior
* Cryptographic verification of state
* High level of trustlessness

## Limitations

* Communication costs scale poorly
* Network latency sensitivity
* Risk of stalls in high-churn environments

## Common misconceptions

* It is a myth that BFT applies only to leader-based protocols. Many people falsely believe that BFT automatically provides censorship resistance.

## Related knowledge

* [Block Producer](/generated/v2/glossary/block-producer) — term
* [Finality](/generated/v2/glossary/finality) — term
* [Proof of Stake](/generated/v2/books/proof-of-stake) — term
* [Validator](/generated/v2/glossary/validator) — term

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**Canonical knowledge ID:** `glossary:byzantine-fault-tolerance`