Bitcoin: How to sign a message with a private key in Bitcoin using TS/JS?

Here’s an article on how to sign a message with a private key using Bitcoin in TypeScript.

Signing Messages with Private Keys in Bitcoin

In this article, we’ll show you how to use the bitcoinjs-lib library to create a private key from your seed phrase and then use it to sign messages. We’ll also demonstrate how to bind the private key to the btcAddress and nftAddress endpoints of our application.

Step 1: Create a Private Key

First, you need to create a private key from your seed phrase. You can do this by running the following command in your terminal:

bc -l < ​​seed_phrase_file_path > private_key.pem

Replace with the path to your seed phrase file.

Step 2: Import Libraries and Load Private Key

Next, we need to import the bitcoinjs-lib library and load our private key:

import * as bitcoin from 'bitcoinjs-lib';

import * as ecc from 'tiny-secp256k1';


const privateKey = await require('./private_key.pem');

Step 3: Create a Message to Sign

Create a message that you want to sign. For example, let’s say we have an NFT contract address and a recipient address:

const contractAddress = '0x...'; // Replace with the contract address

const recipientAddress = '0x...'; // Replace with the recipient address

Step 4: Sign the Message

Now, we can create a BitcoinMessage instance from our message and private key:

const BitcoinMessage = require('bitcoinjs-lib').BitcoinMessage;

const bitcoinMessage = new BitcoinMessage({

  contractAddress,

  recipientAddress,

  data: 'Hello, world!',

});


const signature = await bitcoin.signMessage(privateKey, {

  address: BitcoinMessage.Address.BTC,

  network: BitcoinNetwork.MINECONomy,

});

Step 5: Bind the Private Key to Endpoints

Finally, we need to bind our private key to the btcAddress and nftAddress endpoints of our application:

“`typescript

const bitcoin = require(‘bitcoinjs-lib’);

const ecc = require(‘tiny-secp256k1’);

// Define the endpoints

const contractEndpoint = ‘

const recipientEndpoint = ‘

// Create a private key from the seed phrase file

const privateKey = await require(‘./private_key.pem’);

// Load our private key

const bitcoinPrivateKey = await ecc.keyFromPrivate(privateKey);

// Bind the private key to the endpoints

async function getEndpoint(privateKey) {

const contract = new BitcoinMessage({

contractAddress,

dates: ‘Hello, world!’,

});

const signature = await bitcoin.signMessage(privateKey, {

address: BitcoinMessage.Address.BTC,

network: BitcoinNetwork.MINECONomy,

});

return { contract, signature };

}

async function getContractEndpoint(privateKey) {

// Create a private key from the seed phrase file

const privateKey = await require(‘./private_key.pem’);

const bitcoinPrivateKey = await ecc.keyFromPrivate(privateKey);

// Load our private key

const bitcoin = require(‘bitcoinjs-lib’);

// Bind the private key to the contract endpoint

return new Promise((resolve, reject) => {

getEndpoint(privateKey).then((data) => {

resolve(data);

}).catch((error) => {

reject(error);

});

});

}

async function getRecipientEndpoint(privateKey) {

// Create a private key from the seed phrase file

const privateKey = await require(‘./private_key.pem’);

const bitcoinPrivateKey = await ecc.keyFromPrivate(privateKey);

// Load our private key

const bitcoin = require(‘bitcoinjs-lib’);

// Bind the private key to the recipient endpoint

return new Promise((resolve, reject) => {

getEndpoint(privateKey).then((data) => {

resolve({ contract: data.contract, signature: data.signature });

}).