> For the complete documentation index, see [llms.txt](https://docs.lumia.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lumia.org/ecosystem/lumia/chain-security.md).

# Chain security

**Who this is for:** developers and node operators who want to know what "security" means on Lumia beyond "it's a blockchain": what enforces correct transaction ordering, what enforces correct execution, what backs claims made about off-chain assets, and what has been independently reviewed.

Chain security on Lumia spans four distinct concerns. They fail independently: a valid proof doesn't make an oracle feed honest, and an audit engagement doesn't retroactively cover architecture built after it ran.

```mermaid
flowchart TD
  CS["Chain security on Lumia"] --> S["Sequencer<br/>ordering correctness and liveness"]
  CS --> Z["zkProvers<br/>execution correctness"]
  CS --> O["Oracles and attestation<br/>how external truth reaches the chain"]
  CS --> A["Audits<br/>independent review, scope-limited"]
```

These four fail independently. A valid proof does not make an oracle feed honest, and an audit does not cover architecture built after it ran.

<table data-view="cards"><thead><tr><th></th><th></th><th data-hidden data-card-target data-type="content-ref"></th></tr></thead><tbody><tr><td><strong>Sequencer</strong></td><td>Orders and batches transactions before they are proven and settled. Ordering correctness and liveness live here.</td><td><a href="https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/chain-security/sequencer">https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/chain-security/sequencer</a></td></tr><tr><td><strong>zkProvers</strong></td><td>Generates the proofs that make a sequencer's batches verifiable, so a state transition can't be accepted without a valid proof behind it.</td><td><a href="https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/chain-security/zkprovers">https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/chain-security/zkprovers</a></td></tr><tr><td><strong>Oracles &#x26; Attestation</strong></td><td>How external price data and off-chain claims (reserves, custody) get represented on-chain, and why those are two different trust problems with different failure modes.</td><td><a href="https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/chain-security/oracles-and-attestation">https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/chain-security/oracles-and-attestation</a></td></tr><tr><td><strong>Audits</strong></td><td>The independent security engagements around Lumia, and the scope each one covered.</td><td><a href="https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/chain-security/audits">https://app.gitbook.com/s/chmhPiVNAafGw48c4oU2/ecosystem/lumia/chain-security/audits</a></td></tr></tbody></table>