Feature Request: Add and clear passphrases after entering in seed words in temporary signer mode

[mikeyb233]

When using Jade in temporary signer mode I'd like to be able to add a passphrase and re-compute the private keys and then be able to clear (and maybe enter a different passphrase) without having to renter the seed words.

[JamieDriver]

As it stands you enter the seed words (or, if using a PIN wallet, they are recovered from encrypted flash once the correct PIN is entered) and a passphrase. The words and passphrase are then combined to make a seed, and the wallet root/master keys are then derived from the seed.
At this point the seed, the passphrase used, and the original seed words are discarded.

There are security concerns about keeping the seed words present in memory, and although I do see how what you suggest would be a UX improvement, it is not something we can do without greater investigation/discussion around the potential security issues.

Let's leave this item open for now as a discussion point.