Bitcoin key locker

Continuing to mock up rough ideas for bitcoin applications I'd like to see and use, this one focuses solely on securely storing keys and signing transactions. If this was available across platforms, then every device could be used to sign transactions, making it much easier to use multi signature wallets and therefore improving security for users.

Lots of details not accurate here, it was mostly an exercise to communicate the general idea of such an application. Would be cool to have.

Like the previous concept, this is baed on a free resource: https://www.sketchappsources.com/free-source/4488-macos-big-sur-control-center-sketch-freebie-resource.html