Add ability to import private keys

[ritave]

MyEtherWallet would like to import private keys to Metamask and let them show up as an another account in MetaMask.

Key management snaps should be able to import private keys in a secure way.

This is dependent on Keyrings and Blockkit like UI.

[yashovardhan]

@chaitanyapotti

[rekmarks]

At present, this would probably be implemented by means of a wallet_invokeSnap called within MetaMask itself. Here are some quick thoughts about how this could be implemented:

• We'll need a simple form somewhere in MetaMask where the user can input secrets, perhaps just a single text field for now. For now, this page can probably live in the "snaps view" page in settings.
  • In the future we could support file uploads and all sorts of shenanigans, but a single-line text field is fine for now.
• In order for the snap to receive the secret, we will have to invoke it with a message containing the secret. Therefore, the snap will need to implement an RPC method specified by MetaMask. When the form is submitted, MetaMask will invoke the snap with a request for the RPC method.
  • It needs to be an RPC method as opposed to a notification because we need to be able to tell the user whether the secret import succeeded or not.
• Not every snap will be interested in importing secrets, so every snap will not have use of the form or the RPC method. Therefore, snaps will need to communicate their desire to use the secret import feature. We should probably add a field to the snap manifest for this purpose. It could be something like implementedServices, or requestedServices. If the service secretImports is specified in the manifest, the snap will be expected to implement the RPC method and we will display the requisite UI in MetaMask.
  • Could the secretImports service be a permission? Conceptually, the ability to import secrets is not necessarily a permission because the snap is not being granted a new authority. The snap can already receive information from the outside world, and it is already receiving information from the host.
  • This is just to say I'm on the fence about whether this should be a permission or not, and I'm leaning towards the latter.

[rekmarks]

Hey team! Please add your planning poker estimate with ZenHub @FrederikBolding @Mrtenz @GuillaumeRx @hmalik88 @eriknson

[FrederikBolding]

I may lack some context here, how is this useful as an API to expose to snaps? What's the use case? 🤔

[ritave]

This will be possible with the Snap Keyring Accounts API

[ritave]

@yashovardhan @chaitanyapotti We've been designing a new API that allows snaps to manage accounts in MetaMask. It's possible to import private keys using that APIs. If you would like to shape how the APIs looks so that it can be useful for your case. Now's a good time get involved in discussions