ethereum-identity-provider.js

'use strict'
const IdentityProvider = require('./identity-provider-interface')
const { Wallet, utils } = require('ethers')
const type = 'ethereum'

class EthIdentityProvider extends IdentityProvider {
  constructor (options = {}) {
    super()
    this.wallet = options.wallet
  }

  // Returns the type of the identity provider
  static get type () { return type }

  // Returns the signer's id
  async getId (options = {}) {
    if (!this.wallet) {
      this.wallet = await this._createWallet(options)
    }
    return this.wallet.address
  }

  // Returns a signature of pubkeysignature
  async signIdentity (data, options = {}) {
    const wallet = this.wallet
    if (!wallet) { throw new Error(`wallet is required`) }

    return wallet.signMessage(data)
  }

  static async verifyIdentity (identity) {
    // Verify that identity was signed by the id
    const signerAddress = utils.verifyMessage(identity.publicKey + identity.signatures.id, identity.signatures.publicKey)
    return (signerAddress === identity.id)
  }

  async _createWallet (options = {}) {
    if (options.mnemonicOpts) {
      if (!options.mnemonicOpts.mnemonic) {
        throw new Error(`mnemonic is required`)
      }
      return Wallet.fromMnemonic(options.mnemonicOpts.mnemonic, options.mnemonicOpts.path, options.mnemonicOpts.wordlist)
    }
    if (options.encryptedJsonOpts) {
      if (!options.encryptedJsonOpts.json) {
        throw new Error(`encrypted json is required`)
      }
      if (!options.encryptedJsonOpts.password) {
        throw new Error(`password for encrypted json is required`)
      }
      return Wallet.fromEncryptedJson(options.encryptedJsonOpts.json, options.encryptedJsonOpts.password, options.encryptedJsonOpts.progressCallback)
    }
    return Wallet.createRandom()
  }
}

module.exports = EthIdentityProvider