Apologies if this has been answered elsewhere but I have a question about lockboxes. I understand how to set them up but I'm curious about backup strategies for them.
Your answer is
here. Basically, all you truly need are for the private keys to be backed up (e.g., paper backups), although you can back up the lockbox definition and save yourself some setup time. As long as there are enough signing parties, you're good. If there's corruption, the keys will have to be restored.