Import an existing vault
Bring a vault you built elsewhere, in Fountain, Sparrow or at a key ceremony, into SignBit. You prove one key now, your other keyholders prove theirs later, and the vault keeps working exactly as before.
1. What you need
- A SignBit account with a confirmed email address.
- The vault's two descriptors, one for receiving and one for change. They are public and cannot spend anything.
- Fountain holding one of the vault's keys, so you can prove it is yours.
- About 10 minutes.
Know what changes before you start. SignBit holds no key in an imported vault, so it never co-signs and your keyholders spend on their own. Spending rules you set are kept as a record, but nothing enforces them. A vault's keys are fixed for good, so a SignBit key cannot be added later. If you want SignBit to co-sign, create a new vault instead and move your Bitcoin into it.
2. Get the vault's descriptors
If the vault is saved in Fountain, open Vaults, open the vault and choose Show raw descriptor. If you built it in Fountain with Build one offline, both descriptors appear as soon as you choose Build and save vault. Copy the one under Receive addresses and the one under Change addresses. Other wallets show the same text as the wallet's output descriptor.
3. Start the import
In SignBit, open Vaults and choose Import existing. The page starts with three things to know, the same ones listed above. Read them, because none of them can be undone later.
4. Paste both descriptors
Paste the receive descriptor and the change descriptor into their boxes. If you have a vault backup file (.txt), Import a vault backup file fills both for you. SignBit reads them straight away and lists the vault's keys by fingerprint. Check that the count and the keys are the ones you expect, then choose Continue.
5. Name it and say which key you hold
Give the vault a name and type the fingerprint of the key you hold. Fountain shows it under each key on the Keys screen. You only prove one key now. Then choose Continue.
6. Sign the proof in Fountain
SignBit shows a short text to sign. Choose Copy text to sign, or Show QR if Fountain is on another device. In Fountain, open Sign, choose Message, pick the key you named and paste the text. Fountain labels it Vault import and says it moves no funds. Choose Sign message, then copy the signature.
7. Paste the signature and import
Back in SignBit, paste the signature into Signature from Fountain. You can also use Scan signature or Import file. Choose Import vault. SignBit checks the signature first, and only then creates the vault.
8. Ask the other keyholders to prove their keys
The vault page lists every key. Yours shows Key verified and the others show Not yet proved, because so far only the descriptor names them. Each keyholder proves their own key with Prove this key, or you can Invite them to do it from their own account.
9. Check an address before you deposit
SignBit now shows the vault's addresses, balance and history. Before you send anything to it, compare the first receive address with the one Fountain works out on its own under Derive an address. The check a receive address guide walks through it.