How to Back Up a Multi-Party Key Setup

This guide covers how to back up a distributed-key, multi-party setup properly. It's written for anyone already using or planning to use split-key signing across more than one device or person.

Backup Steps

1. Identify how many key shares exist in total and exactly where each one is currently held, including any shares held by other people.
2. Confirm the minimum number of shares required to sign, so you know your real margin for loss before something actually goes missing.
3. Store each share independently, in separate physical locations and ideally with separate custodians, rather than grouping them together for convenience.
4. Test a full recovery or signing scenario using the backups before you depend on the setup for regular, day-to-day use.
5. Plan explicitly for one device or share becoming unavailable, and confirm the remaining shares still meet the signing threshold on their own.

What to Watch For

Storing shares in the same place defeats the purpose of splitting them in the first place — it just recreates a single point of failure under a different name. Keep them apart, and revisit the plan whenever a device, location, or custodian changes.

For the underlying architecture, see Key Security, and for general recovery steps once a device is lost, see How to Recover a Wallet After Losing a Device. A backup plan you've actually tested is worth far more than one that only looks complete on paper.