TL;DR
Export the wallet descriptor and put a copy with every seed backup. It holds no private keys, but without it two seeds aren’t enough to find your coins.
What you need
- The wallet from step 6
- One USB stick per backup location
- A printer, preferably a laser printer
Why this matters
Your addresses are calculated from all three xpubs together. Lose one seed and you can no longer work out that device’s xpub, so you can’t calculate your addresses either, even with the other two seeds in your hands. The descriptor contains all three xpubs. So if you lose a seed, which is exactly what 2-of-3 is for, you also need the descriptor.
The good news: the descriptor is safe to copy. Someone who has it can’t spend anything. They can see your addresses and balance. That’s bad for privacy, but it can’t cost you coins. So make plenty of copies of this one.
Steps
- In Sparrow, open the wallet’s Settings tab, click the QR-code icon next to Descriptor, then Save PDF. The PDF has the descriptor as text and as a QR code.
- Also click Export, choose Output Descriptor and save it as a text file on each USB stick. Give it a clear name, like
vault-2of3-descriptor.txt. - Print the PDF once per location. Paper lasts longer than flash memory, and the QR code saves you from retyping it later.
- On each printed sheet, write which device letter belongs to which master fingerprint.
- Put one USB stick and one printout in each box, next to the seed plate, in a zip bag.
- Extra digital copies are welcome: your password manager, an encrypted cloud folder. This goes for the descriptor only.
Descriptor yes, seed never
The USB stick and the cloud are fine for the descriptor because it holds only public keys. Seed words never go on a USB stick, in a password manager or anywhere digital.
Common mistakes
- Keeping the descriptor only in the wallet file on the signing laptop.
- Treating it like a secret and hiding one single copy very well.
- Forgetting to update the backups after building a second vault.