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

# Blockchain Integration

> DNA as the final permanence layer for blockchain histories  cryptographically anchored, verifiable, and recoverable across centuries.

Blockchains generate massive volumes of data. Every transaction, contract state, and block must remain verifiable indefinitely. While pruning and snapshots reduce active storage, full histories must be preserved for security and trust. DNA provides a final layer of permanence for this data.

## Archival of Full Histories

Complete blockchain histories can be encoded into DNA as immutable archives. Instead of relying on centralized providers to keep terabytes of data online, nodes and researchers can access molecular archives that preserve the full ledger across centuries.

## On-Chain Proofs

<CardGroup cols={2}>
  <Card title="Proof of Write" icon="pen">
    When data is written to DNA, a cryptographic commitment of the identifiers
    is anchored on-chain. This binds the molecular archive to its digital
    representation and proves the archive was produced correctly.
  </Card>

  <Card title="Proof of Query" icon="magnifying-glass">
    In-DNA compute allows biochemical search before sequencing. Query results
    can be sequenced and hashed on-chain verifiable proof that a query was
    executed on the physical archive without resequencing the entire dataset.
  </Card>
</CardGroup>

## Use Cases

<CardGroup cols={2}>
  <Card title="Light Client Recovery" icon="rotate">
    Nodes joining a network in the future can retrieve DNA-archived checkpoints
    to reconstruct blockchain state without downloading years of peer data
    making blockchains more resilient across decades of operation.
  </Card>

  <Card title="Trust Vault for DeFi & DeSci" icon="vault">
    Smart contracts, financial ledgers, and scientific datasets committed to DNA
    as a permanent trust layer. On-chain anchoring means disputes or audits can
    always be resolved by retrieving the original molecular data.
  </Card>

  <Card title="Multi-Chain Archival" icon="diagram-project">
    Multiple chains or networks can be archived in the same molecular library.
    Keys are allocated per chain or per dataset, allowing multi-chain archival
    in a single DNA batch.
  </Card>

  <Card title="Historical Audits" icon="clock-rotate-left">
    Forensic and compliance audits can query DNA archives biochemically and
    surface relevant transactions without a full scan orders of magnitude faster
    than tape-based alternatives.
  </Card>
</CardGroup>

<Note>
  Because identifiers are assembled in combinatorial address spaces, multiple
  chains can be archived in the same molecular library keys allocated per chain
  allow multi-chain archival in a single DNA batch.
</Note>