a key (either a deterministically derived child, or just the master depending on the privacy required)
a process for receiving something to sign from Service
a process for transmitting the signature to Service
Seems like (2) and (3) should probably just use a relay that the Service suggests when giving you something to sign, perhaps reusing encrypted messaging/DMs.
You need:
Seems like (2) and (3) should probably just use a relay that the Service suggests when giving you something to sign, perhaps reusing encrypted messaging/DMs.