bip86/src/index.js

BIP86 - Derives taproot addresses from seed, xprv/xpub and tprv/tpub in javascript

const { networks } = require('bitcoinjs-lib')
const bip39 = require('bip39')
const bitcoinNetworks = { mainnet: networks.bitcoin, testnet: networks.testnet }
const { BIP32Factory } = require('bip32')
const ecurve = require('ecurve')
const secp256k1 = ecurve.getCurveByName('secp256k1')
const schnorr = require('bip-schnorr')
const { bech32, bech32m } = require('bech32')
const ecc = require('@bitcoinerlab/secp256k1');
const bip32 = BIP32Factory(ecc);

/**
 * Constructor
 * Derive accounts from a mnemonic.
 * @param {string} mnemonic
 * @param {string} password
 * @param {boolean} isTestnet
 * @param {number} coinType - slip44
 * @param {object} network
 * @return 
 */
class fromMnemonic {
  constructor(mnemonic, password = '', isTestnet, coinType, network) {
    this.seed = bip39.mnemonicToSeedSync(mnemonic, password)
    this.isTestnet = isTestnet === true
    this.coinType = this.isTestnet ? 1 : coinType ? coinType : 0 // 0 is for Bitcoin and 1 is testnet for all coins
    this.network = network || this.isTestnet ? bitcoinNetworks.testnet : bitcoinNetworks.mainnet
  }

  /**
   * Get root master private key
   * @return {string}
   */
  getRootPrivateKey() {
    let xprv = bip32.fromSeed(this.seed, this.network).toBase58()

    return xprv
  }

  /**
   * Get root master public key
   * @return {string}
   */
  getRootPublicKey() {
    let xpub = bip32.fromSeed(this.seed, this.network).neutered().toBase58()

    return xpub
  }

  /**
   * Derive a new master private key
   * @param {number} number
   * @param {number} changePurpose
   * @return {string}
   */
  deriveAccount(number, changePurpose) {
    let purpose = changePurpose || 86
      , keypath = "m/" + purpose + "'/" + this.coinType + "'/" + number + "'"
      , account = bip32.fromSeed(this.seed, this.network).derivePath(keypath).toBase58()

    return account
  }
}

/**
 * Constructor
 * Create key pairs from a private master key of mainnet and testnet.
 * @param {string} xprv/tprv
 * @param {object} networks
 */
class fromXPrv {
  constructor(xprv, networks) {
    this.networks = networks || bitcoinNetworks
    this.xprv = xprv
    this.getNetwork(xprv)
  }

  /**
   * Test supported prefixes and configure the network
   * @return {string}
   */
  getNetwork(xprv) {
    let key = xprv.slice(0, 4)

    if (key !== 'xprv' && key !== 'tprv') {
      throw new Error('prefix is not supported')
    }

    if (key === 'xprv') {
      this.network = this.networks.mainnet
      this.isTestnet = false
    }

    if (key === 'tprv') {
      this.network = this.networks.testnet
      this.isTestnet = true
    }
  }

  /**
   * Get account master private key
   * @return {string}
   */
  getAccountPrivateKey() {
    let xprv = bip32.fromBase58(this.xprv, this.network).toBase58()

    return xprv
  }

  /**
   * Get account master public key
   * @return {string}
   */
  getAccountPublicKey() {
    let xpub = bip32.fromBase58(this.xprv, this.network).neutered().toBase58()

    return xpub
  }

  /**
   * Get private key
   * @param {number} index
   * @param {boolean} isChange
   * @return {string}
   */
  getPrivateKey(index, isChange) {
    let change = isChange === true ? 1 : 0
      , prvkey = bip32.fromBase58(this.xprv, this.network).derive(change).derive(index)

    return prvkey.toWIF()
  }

  /**
   * Get public key
   * @param {number} index
   * @param {boolean} isChange
   * @return {string}
   */
  getPublicKey(index, isChange) {
    let change = isChange === true ? 1 : 0
      , pubKey = bip32.fromBase58(this.xprv, this.network).derive(change).derive(index).publicKey

    return pubKey.toString('hex')
  }

  /**
   * Get address
   * @param {number} index
   * @param {boolean} isChange
   * @return {string}
   */
  getAddress(index, isChange) {
    let change = isChange === true ? 1 : 0
      , pubkey = bip32.fromBase58(this.xprv, this.network).derive(change).derive(index).publicKey

    return getP2TRAddress(pubkey, this.isTestnet)
  }
}

/**
 * Constructor
 * Create public keys and addresses from a public master key of mainnet and testnet.
 * @param {string} xpub/tpub
 * @param {object} networks
 */
class fromXPub {
  constructor(xpub, networks) {
    this.networks = networks || bitcoinNetworks
    this.xpub = xpub
    this.getNetwork(xpub)
  }

  /**
   * Test supported prefixes and configure the network
   * @return {string}
   */
  getNetwork(xpub) {
    let key = xpub.slice(0, 4)

    if (key !== 'xpub' && key !== 'tpub') {
      throw new Error('prefix is not supported')
    }

    if (key === 'xpub') {
      this.network = this.networks.mainnet
      this.isTestnet = false
    }

    if (key === 'tpub') {
      this.network = this.networks.testnet
      this.isTestnet = true
    }
  }

  /**
   * Get account master public key
   * @return {string}
   */
  getAccountPublicKey() {
    let xpub = bip32.fromBase58(this.xpub, this.network).neutered().toBase58()

    return xpub
  }

  /**
   * Get public key
   * @param {number} index
   * @param {boolean} isChange
   * @return {string}
   */
  getPublicKey(index, isChange) {
    let change = isChange === true ? 1 : 0
      , xpub = bip32.fromBase58(this.xpub, this.network).derive(change).derive(index)

    return xpub.publicKey.toString('hex')
  }

  /**
   * Get address
   * @param {number} index
   * @param {boolean} isChange
   * @return {string}
   */
  getAddress(index, isChange) {
    let change = isChange === true ? 1 : 0
      , pubkey = bip32.fromBase58(this.xpub, this.network).derive(change).derive(index).publicKey

    return getP2TRAddress(pubkey, this.isTestnet)
  }
}

const getP2TRAddress = (pubkey, testnet = false) => {
  const pubKey = ecurve.Point.decodeFrom(secp256k1, pubkey)
  const taprootPubkey = schnorr.taproot.taprootConstruct(pubKey)
  const words = bech32.toWords(taprootPubkey)
  words.unshift(1)
  return bech32m.encode(testnet ? 'tb' : 'bc', words)
}

module.exports = {
  generateMnemonic: bip39.generateMnemonic,
  entropyToMnemonic: bip39.entropyToMnemonic,
  fromMnemonic,
  fromXPrv,
  fromXPub
}