HD Keyring

A simple JS class wrapped around ethereumjs-wallet designed to expose an interface common to many different signing strategies, to be used in a KeyringController, like is being used in MetaMask

Installation

yarn add @metamask/eth-hd-keyring

or

npm install @metamask/eth-hd-keyring

The Keyring Class Protocol

One of the goals of this class is to allow developers to easily add new signing strategies to MetaMask. We call these signing strategies Keyrings, because they can manage multiple keys.

Keyring.type

A class property that returns a unique string describing the Keyring. This is the only class property or method, the remaining methods are instance methods.

constructor( options )

As a Javascript class, your Keyring object will be used to instantiate new Keyring instances using the new keyword. For example:

const keyring = new YourKeyringClass(options);

The constructor currently receives an options object that will be defined by your keyring-building UI, once the user has gone through the steps required for you to fully instantiate a new keyring. For example, choosing a pattern for a vanity account, or entering a seed phrase.

We haven't defined the protocol for this account-generating UI yet, so for now please ensure your Keyring behaves nicely when not passed any options object.

Keyring Instance Methods

All below instance methods must return Promises to allow asynchronous resolution.

serialize()

In this method, you must return any JSON-serializable JavaScript object that you like. It will be encoded to a string, encrypted with the user's password, and stored to disk. This is the same object you will receive in the deserialize() method, so it should capture all the information you need to restore the Keyring's state.

deserialize( object )

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

addAccounts( n = 1 )

The addAccounts(n) method is used to inform your keyring that the user wishes to create a new account. You should perform whatever internal steps are needed so that a call to serialize() will persist the new account, and then return an array of the new account addresses.

The method may be called with or without an argument, specifying the number of accounts to create. You should generally default to 1 per call.

getAccounts()

When this method is called, you must return an array of hex-string addresses for the accounts that your Keyring is able to sign for.

signTransaction(address, transaction)

This method will receive a hex-prefixed, all-lowercase address string for the account you should sign the incoming transaction with.

For your convenience, the transaction is an instance of ethereumjs-tx, (https://github.com/ethereumjs/ethereumjs-tx) so signing can be as simple as:

transaction.sign(privateKey)

You must return a valid signed ethereumjs-tx (https://github.com/ethereumjs/ethereumjs-tx) object when complete, it can be the same transaction you received.

signMessage(address, data)

The eth_sign method will receive the incoming data, alread hashed, and must sign that hash, and then return the raw signed hash.

exportAccount(address)

Exports the specified account as a private key hex string.

Contributing

Setup

• Install Node.js version 12
  • If you are using nvm (recommended) running nvm use will automatically choose the right node version for you.
• Install Yarn v1
• Run yarn setup to install dependencies and run any requried post-install scripts
  • Warning: Do not use the yarn / yarn install command directly. Use yarn setup instead. The normal install command will skip required post-install scripts, leaving your development environment in an invalid state.

Testing and Linting

Run yarn test to run the tests once. To run tests on file changes, run yarn test:watch.

Run yarn lint to run the linter, or run yarn lint:fix to run the linter and fix any automatically fixable issues.

Release & Publishing

The project follows the same release process as the other libraries in the MetaMask organization. The GitHub Actions action-create-release-pr and action-publish-release are used to automate the release process; see those repositories for more information about how they work.

1. Choose a release version.

   • The release version should be chosen according to SemVer. Analyze the changes to see whether they include any breaking changes, new features, or deprecations, then choose the appropriate SemVer version. See the SemVer specification for more information.

2. If this release is backporting changes onto a previous release, then ensure there is a major version branch for that version (e.g. 1.x for a v1 backport release).

   • The major version branch should be set to the most recent release with that major version. For example, when backporting a v1.0.2 release, you'd want to ensure there was a 1.x branch that was set to the v1.0.1 tag.

3. Trigger the workflow_dispatch event manually for the Create Release Pull Request action to create the release PR.

   • For a backport release, the base branch should be the major version branch that you ensured existed in step 2. For a normal release, the base branch should be the main branch for that repository (which should be the default value).
   • This should trigger the action-create-release-pr workflow to create the release PR.

4. Update the changelog to move each change entry into the appropriate change category (See here for the full list of change categories, and the correct ordering), and edit them to be more easily understood by users of the package.

   • Generally any changes that don't affect consumers of the package (e.g. lockfile changes or development environment changes) are omitted. Exceptions may be made for changes that might be of interest despite not having an effect upon the published package (e.g. major test improvements, security improvements, improved documentation, etc.).
   • Try to explain each change in terms that users of the package would understand (e.g. avoid referencing internal variables/concepts).
   • Consolidate related changes into one change entry if it makes it easier to explain.
   • Run yarn auto-changelog validate --rc to check that the changelog is correctly formatted.

5. Review and QA the release.

   • If changes are made to the base branch, the release branch will need to be updated with these changes and review/QA will need to restart again. As such, it's probably best to avoid merging other PRs into the base branch while review is underway.

6. Squash & Merge the release.

   • This should trigger the action-publish-release workflow to tag the final release commit and publish the release on GitHub.

7. Publish the release on npm.

   • Be very careful to use a clean local environment to publish the release, and follow exactly the same steps used during CI.
   • Use npm publish --dry-run to examine the release contents to ensure the correct files are included. Compare to previous releases if necessary (e.g. using https://unpkg.com/browse/[package name]@[package version]/).
   • Once you are confident the release contents are correct, publish the release using npm publish.