$1.88 lock wallet with pin / password / biometrics

[DanGould]

e.g Authenticate with password post wallet creation to solve the same problem as #56 where people lose money after creation by funding a wallet they don't have the password for.

This could also be solved by using the operating system / device encryption as in Green

affected 5
importance 3
difficulty 8

[MaxHillebrand]

I'd probably not use Wasabi's screen lock feature, as this is no real security, it can easily be circumvented.

[DanGould]

The idea would be to lock the wallet and ask users to unlock by encrypting the wallet.json until users enter a pin (optionally a legacy password) or using biometrics to decrypt one.

This would not only provide security but also allow time for the basic wallet services and tor to start.

We would also be able to comfortably remove the password requirement to generate a payment request given this improvement. Along with this change it makes sense to provide a cover screen for the app drawer to not reveal information when scrolling through. Signal does this with a splash screen that gets set. By adding this type of encryption we could enable biometrics for send & coinjoin approval as well.