> For the complete documentation index, see [llms.txt](https://protocol.hang.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://protocol.hang.com/the-protocol/sentinel-nodes.md).

# Sentinel Nodes

## Sentinels

**Sentinel Nodes** can register with the Hang Foundation by staking a minimum of 1.0 ETH. This allows Sentinel Nodes to post claims to the **Referee Contract** in the event of a disagreement. In the case where the referee verifiies a sentinel claim, the sentinel is paid a reward.

## Referee Contract

The referee smart contract operates in the following manner:

1. Sentinels post an assertion
2. Assertion is accepted or denied
3. If assertion is accepted
   1. Corrected sucessor state is appended to chain
   2. Reporting sentinel collects reward