mpc/docs/XRPL_INTEGRATION.md

XRPL Integration Guide

This guide explains how to use the Lux MPC library for XRP Ledger (XRPL) transaction signing.

Overview

The Lux MPC library now includes explicit support for XRPL networks. XRPL uses secp256k1 signatures for transaction authorization, which is fully supported by our threshold signature implementation.

Supported Networks

• XRPL - XRP Ledger Mainnet
• XRPL-testnet - XRP Ledger Testnet
• XRPL-devnet - XRP Ledger Devnet

Key Type

XRPL uses secp256k1 (ECDSA) signatures. The library automatically selects the correct key type when you specify an XRPL network code.

Usage Example

import (
    "github.com/luxfi/mpc/pkg/types"
    "github.com/luxfi/mpc/pkg/client"
)

// Create signing request for XRPL
signingMsg := &types.SignTxMessage{
    WalletID:            "your-wallet-id",
    TxID:                "unique-tx-id",
    Tx:                  xrplTransactionBytes,
    KeyType:             types.KeyTypeSecp256k1,
    NetworkInternalCode: string(types.NetworkXRPL),
}

// Sign the transaction
err := mpcClient.SignTransaction(signingMsg)

Transaction Format

XRPL transactions should be provided as serialized bytes according to the XRPL binary codec specification. The typical flow is:

1. Create XRPL transaction JSON
2. Serialize using XRPL binary codec
3. Pass serialized bytes to MPC for signing
4. Apply signature to transaction
5. Submit to XRPL network

Integration with ripple-lib

When integrating with JavaScript XRPL libraries:

const RippleAPI = require('ripple-lib').RippleAPI;
const api = new RippleAPI();

// Create transaction
const txJSON = {
  TransactionType: 'Payment',
  Account: 'rN7n7otQDd6FczFgLdSqtcsAUxDkw6fzRH',
  Destination: 'rLNaPoKeeBjZe2qs6x52yVPZpZ8td4dc6w',
  Amount: '1000000', // 1 XRP in drops
  Fee: '12',
  Sequence: 1
};

// Serialize transaction (prepare for signing)
const serialized = api.encodeTransaction(txJSON);

// Send serialized bytes to MPC for signing
// ... MPC signing process ...

// Apply MPC signature to transaction
const signedTx = {
  ...txJSON,
  TxnSignature: mpcSignature
};

// Submit to XRPL
api.submit(signedTx);

Security Considerations

1. Key Derivation: XRPL uses specific key derivation paths. Ensure your wallet implementation follows XRPL standards.

2. Transaction Validation: Always validate transaction data before signing:

   • Check destination addresses
   • Verify amounts
   • Confirm fees are reasonable
   • Validate sequence numbers

3. Network Selection: Always specify the correct network code to prevent signing mainnet transactions with testnet keys or vice versa.

Testing

Run XRPL-specific tests:

go test ./e2e -run TestXRPL

Network Configuration

The supported networks are defined in pkg/types/networks.go:

const (
    NetworkXRPL        NetworkCode = "XRPL"
    NetworkXRPLTestnet NetworkCode = "XRPL-testnet"
    NetworkXRPLDevnet  NetworkCode = "XRPL-devnet"
)

Error Handling

Common XRPL-related errors:

• Invalid network code: Ensure you're using one of the supported XRPL network codes
• Wrong key type: XRPL only supports secp256k1 signatures
• Invalid transaction format: Ensure proper XRPL transaction serialization

References

• XRPL Documentation
• XRPL Binary Codec
• XRPL Transaction Types