eth-zymbit-keyring

An implementation of MetaMask's Keyring interface for Zymbit devices with built-in hardware wallets (HSM6 and SCM).

Table of Contents

• Overview
• Installation
• Usage
  • ZymbitKeyring.type
  • constructor(options)
• Zymbit Keyring Instance Methods
  • serialize()
  • deserialize(object)
  • addAccounts(n = 1)
  • getAccounts()
  • signTransaction(address, transaction)
  • signMessage(address, data)
  • removeAccount(address)
• Testing

Overview

For the most part, it works the same way as eth-hd-keyring, but uses a Zymbit HSM6 or SCM to store the keys and perform any signing operations. However, there are some differences:

• It requires that you have an HSM6 or SCM attached to a supported embedded device (Raspberry Pi or Jetson Nano)
• All cryptographic operations involving keys are performed on the module itself
• Zymbit devices don't support exporting private keys, so it does not support the exportAccount() method

Installation

Run the following command:

yarn add eth-zymbit-keyring

or

npm install eth-zymbit-keyring

Usage

const ZymbitKeyring = require('eth-zymbit-keyring')
const options = {
    wallet_name: "MyExampleWallet",
    master_slot: 16
}
const keyring = new ZymbitKeyring(options);

ZymbitKeyring.type

A class property that returns Zymbit Hardware Wallet

constructor(options)

The constructor receives an options object that requires either a valid wallet_name or master_slot property. In order to use this, you must have created or recovered a BIP39 wallet through Zymbit's API.

Zymbit Keyring Instance Methods

All below instance methods return Promises to allow asynchronous resolution.

serialize()

Returns a JSON-serializable object with the wallet_name or master_slot properties of the keyring. This object can be passed into deserialize() to recover the state of the keyring.

deserialize(object)

As discussed above, the deserialize() method will be passed the JSON object that was returned when the serialize() method was called.

addAccounts( n = 1 )

Used to add new accounts to the keyring starting from m/44'/60'/0'/0 and incrementing the last index each time. Takes the number of accounts you want to add to the keyring n as a parameter (defaults to n = 1), and returns an array of size n including the Ethereum addresses of the accounts added.

getAccounts()

Returns an array of hex-string addresses for the Ethereum accounts that the keyring is able to sign for.

signTransaction(address, transaction)

Takes a hex-prefixed address string for the account you want to use to sign the incoming transaction with. The transaction is an instance of ethereumjs-tx. Returns a signed ethereumjs-tx object when complete.

signMessage(address, data)

Takes a pre-hashed message (data) and signs it using the account of the hex-prefixed address passed in. Returns the complete hex-prefixed ECDSA signature.

removeAccount(address)

Removes the account corresponding to the hex-prefixed address passed in from the keyring and the Zymbit device.

Testing

Run the following command:

npm test