Bitcoin Transaction Proof

A TypeScript library for generating Bitcoin transaction proofs, including witness data and merkle proofs. This package helps developers verify Bitcoin transactions and their inclusion in blocks, supporting both SegWit and non-SegWit transactions.

Features

• Generate transaction proofs with witness data
• Calculate merkle proofs for transaction verification
• Support for both SegWit and non-SegWit transactions
• Built-in caching and rate limiting for RPC calls
• Works with any Bitcoin node (local or remote)
• Full TypeScript support

Installation

npm install bitcoin-tx-proof

Quick Start

import { bitcoinTxProof } from "bitcoin-tx-proof";

// Get proof for a transaction
const proof = await bitcoinTxProof(
  "4a5e1e4baab89f3a32518a88c31bc87f618f76673e2cc77ab2127b7afdeda33b", // txid
  277316, // block height
  {
    url: "http://localhost:8332",
    username: "your_rpc_username", // optional
    password: "your_rpc_password", // optional
  }
);

API Reference

Main Function

bitcoinTxProof(txid, blockHeight, rpcConfig)

Generates a complete transaction proof including witness data.

Parameters:

• txid: string - The transaction ID to generate proof for
• blockHeight: number - The block height containing the transaction
• rpcConfig: BitcoinRPCConfig - Configuration for Bitcoin RPC connection

Returns: Promise

Types:

interface BitcoinRPCConfig {
  url: string;          // Bitcoin RPC endpoint URL
  username?: string;    // Optional RPC username
  password?: string;    // Optional RPC password
}

interface TxProofResult {
  blockHeight: number;          // Height of the block
  transaction: string;          // Raw transaction hex
  blockHeader: string;          // Block header hex
  txIndex: number;             // Index in block
  merkleProofDepth: number;    // Merkle tree depth
  witnessMerkleProof: string;  // Witness merkle proof
  witnessReservedValue: string;// Witness reserved value
  coinbaseTransaction: string; // Coinbase transaction
  coinbaseMerkleProof: string;// Coinbase merkle proof
}

Advanced Usage

Direct RPC Access

import { BitcoinRPC } from 'bitcoin-tx-proof';

const rpc = new BitcoinRPC({
  url: 'http://localhost:8332',
  username: 'rpcuser',
  password: 'rpcpassword'
});

// Make any Bitcoin RPC call
const blockHash = await rpc.call('getblockhash', [500000]);
const block = await rpc.call('getblock', [blockHash]);

Merkle Calculations

import { calculateWTXID, getMerkleProof } from 'bitcoin-tx-proof';

// Calculate witness txid
const wtxid = calculateWTXID(transactionHex);

// Generate merkle proof
const proof = getMerkleProof(txHashes, txIndex);

Error Handling

try {
  const proof = await bitcoinTxProof(txid, blockHeight, rpcConfig);
} catch (error) {
  if (error.message.includes('Invalid transaction ID')) {
    // Handle invalid txid
  } else if (error.message.includes('RPC Error')) {
    // Handle RPC connection issues
  } else if (error.message.includes('Transaction not found')) {
    // Handle missing transaction
  }
}

Performance Features

Caching

• Built-in caching for RPC calls (10-minute TTL)
• Automatic cache invalidation
• Memory-efficient caching strategy

Rate Limiting

• Automatic rate limiting (10 requests/second)
• Configurable limits
• Queue management for concurrent requests

Development

# Install dependencies
npm install

# Run tests
npm test

# Build
npm run build

# Lint
npm run lint

# Format code
npm run format

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

MIT