# Cardano · Integra

> On Cardano, a CIP-20 message holds the ATR hash, committed by the signed body.

URL: https://integraledger.com/rails/cardano

Payment rail

## Cardano

On Cardano, a CIP-20 message holds the ATR hash, committed by the signed body. [Source: lcp docs: rails⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/docs/guides/rails.md)

**Sources (1)**

[lcp docs: rails⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/docs/guides/rails.md)

### Where the ATR hash rides

On this rail, the ATR hash rides in a CIP-20 message.

#### The standard

- A CIP-20 message (metadata label 674) holding H’s LCP string as two strings, `lcp:sha256:0x` and the 64 lowercase hex digits, which the signed body commits to through `auxiliary_data_hash`. [Source: lcp docs: rails⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/docs/guides/rails.md)

  `x402/exact/cardano`

Entry points: `@integraledger/lcp/cardano`

#### The data

Read from the published packages when the site was built; nothing here is typed by hand.

The ATR hash of the site’s example ATR, as this rail carries it

H’s LCP string, as a CIP-20 message in two strings

lcp:sha256:0x8448dc1b716a5103287cb8f35e36b614ffd91e630ab8b7911833c54748ad5ca6

Computed from the site’s example ATR by this rail’s own helper in the package, when the site was built.

### What a payment on this rail proves

Of these 1 pairings, 1 have the buyer’s signature cover the ATR hash, 1 leave a public proof of it, and 1 let anyone read it back from the chain alone. [Source: lcp docs: pairings reference⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/docs/reference/pairings.md)

Switch to Technical to see each pairing, and the sentence its record states about what a payment through it proves.

#### The standard

- **`x402/exact/cardano` Native Field Buyer signs H: yes H on chain: yes Public proof: yes Recoverable from chain: yes**

  Pattern: [Native Field (LCP §8.3.1)⁠ (opens in a new tab)](https://github.com/legal-context-protocol/legal-context-protocol/blob/c8df26d/spec/legal-context-protocol-v1.md#831-native-field)

  Where the ATR hash rides: A CIP-20 message (metadata label 674) holding H’s LCP string as two strings, `lcp:sha256:0x` and the 64 lowercase hex digits, which the signed body commits to through `auxiliary_data_hash`.

  What a payment through it proves: The payer signed a Cardano transaction whose body commits, through its auxiliary_data_hash, to a CIP-20 message (label 674) carrying this ATR's hash. The ledger included the transaction as valid, at the stated depth; the rail allows a rollback of fewer than k blocks. The hash is in the transaction's metadata on chain. This does not show that amount, payee, asset or timing match the ATR's content.

  LCP profile: [x402/exact/cardano⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/lcp/profiles/x402-exact-cardano.md)

### Reading the settlement

The package reads a payment’s settlement through a reader you supply: the endpoint, the credentials, the timeouts and the retries are yours. A reader that fails never makes a payment read as failed. [Source: lcp docs: reading settlement⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/docs/guides/rails.md#reading-settlement)

**Sources (1)**

[lcp docs: reading settlement⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/docs/guides/rails.md#reading-settlement)

#### The standard

**Reader**

`CardanoReader`

**Its calls**

the chain tip, the transaction by id

**A settled read carries**

the confirmations [Source: lcp docs: reading settlement⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/docs/guides/rails.md#reading-settlement)

### The protocols that pay on it

- [x402](https://integraledger.com/protocols/x402)

[lcp docs: rails⁠ (opens in a new tab)](https://github.com/IntegraLedger/integra-protocol/blob/66274bf/docs/guides/rails.md)