Creating a private public key with 64 characters that are already known using bitcoinjs

Question

So I'm trying to create a private/public key from 64 characters that I already know using bitcoinjs with the code below:

key = Bitcoin.ECKey.makeRandom();

// Print your private key (in WIF format)
document.write(key.toWIF());
// => Kxr9tQED9H44gCmp6HAdmemAzU3n84H3dGkuWTKvE23JgHMW8gct

// Print your public key (toString defaults to a Bitcoin address)
document.write(key.pub.getAddress().toString());
// => 14bZ7YWde4KdRb5YN7GYkToz3EHVCvRxkF

If I try to set "key" to my 64 characters instead of "Bitcoin.ECKey.makeRandom();" it fails. Is there a method or library that I overlooked that would allow me to use the known 64 characters in order to generate the private key in wif format and the public address?

Answer 1

You should use fromWIF method to pass your own data.

from source code of eckey.js

// Static constructors
ECKey.fromWIF = function(string) {
  var payload = base58check.decode(string)
  var compressed = false

  // Ignore the version byte
  payload = payload.slice(1)

  if (payload.length === 33) {
    assert.strictEqual(payload[32], 0x01, 'Invalid compression flag')

    // Truncate the compression flag
    payload = payload.slice(0, -1)
    compressed = true
  }

To create WIF from your key please follow https://en.bitcoin.it/wiki/Wallet_import_format Here is interactive tool http://gobittest.appspot.com/PrivateKey

Answer 2

//public-key
var address = eckey.getBitcoinAddress().toString();

var privateKeyBytesCompressed = privateKeyBytes.slice(0); 
privateKeyBytesCompressed.push(0x01);
var privateKeyWIFCompressed = new Bitcoin.Address(privateKeyBytesCompressed);
privateKeyWIFCompressed.version = 0x80;


//private-key
privateKeyWIFCompressed = privateKeyWIFCompressed.toString();