Namadillo: Discuss UX for additional shielded accounts

[jurevans]

We should further discuss the UX implications of allowing the user to generate additional payment addresses from a spending key, and what this could mean for the existing flows as we have them.

• Should we (and how could we) support having a shielded account that doesn't have a transparent counterpart?
• Could we instead have multiple shielded keys associated with a single (parent) transparent account seed? (Use-case is generating additional shielded keys - This functionality would simply increase the derivation path index for the account)
  • How would this affect shielding and unshielding flows?

Basically, what are the consequences of having only shielded or transparent keys as a single account? We group these currently by:

1. Generating a Transparent account (contains the mnemonic seed)
2. Deriving Shielded Keys from this Transparent Account, reference it by a parent ID (this is how they are linked together to display View Keys in the extension)

Currently, the Extension accounts flow looks like this:

• User Generates/Imports a Mnemonic -> Transparent + Shielded Keys (default paths)
• User Imports a Mnemonic with Custom Path -> As of 1155, Transparent + Shielded Keys (unless they specify change, which is not a component of Zip32, so shielded accounts get ignored here)
• User Imports a Private Key -> Transparent (However, it's now possible to also generate shielded keys from this private key, so we can probably ignore this as it will be added soon - so assume this is the same as in first scenario)
• User generates additional payment address from shielded account (Not currently implemented) - How will this be represented on Namadillo? Should users also have ability to select from other accounts in the extension that are not associated with the shielded/transparent key that is selected in Extension?