By default, you sign your
2-of-3 transactions on your
2 hardware wallets (Keystone (formerly Cobo Vault) and Coldcard) that you previously configured.
If either device is damaged/destroyed, you should replace it with a new one and load the replacement device with the same seed phrase that you previously backed up.
This means that if seed phrase A was on your Keystone and your Keystone was destroyed in a fire, you would do the following:
- Buy a new Keystone.
- Find the backup of seed phrase A that you previously made.
- Load seed phrase A onto your new (replacement) Keystone.
- Follow the previous hardware wallet setup steps to add the new device into your multisig.
However, if for any reason that doesn’t work (perhaps devices are sold out or the company has gone out of business), you can load that BIP39 seed onto another device.
For this, we have two recommendations: Trezor (hardware wallet) and Electrum (software wallet). Both have tradeoffs, and we hope that there will be better options in the future. BIP39 is the gold standard supported by all major hardware wallets, so we expect it will continue to be compatible with new hardware wallets as they are developed in the future.
As there are “gotchas” in both of the below setups, we recommend you read the advanced section for tips to improve your setup.
Option A - Trezor
You should be aware that this is a little more complicated than hardware wallets you setup previously, and there are some pitfalls to avoid (see known issues).
TODO: add explanation/screenshots.
Option B - Electrum
Electrum is an open-source software wallet that is free and readily available, but difficult to use with multisig. As it will be touching private key material, we strongly recommend you run this on an airgapped machine (see advanced section).
TODO: add screenshots.
- Download and install Electrum from electrum.org.
- Create a new multisignature wallet using the wizard, and select “2 of 3” as your quorum.
- Using your Specter-Desktop wallet backup file, identify your
Zpubs from the JSON file.
- For the first two keys (Coldcard and Keystone), import the
Zpubmaster public keys into the Electrum multisignature wizard as keys in the multisignature quorum, ensuring the pathway matches the one Specter-Desktop wallet used e.g.
m/48'/0'/0'/2'. Electrum will display these as
- For the seedpicker paper wallet, select private keys, and Electrum will present a box to type in your seedpicker seed. Ensure you use the drop-down menu to select that this is a BIP39 seed or otherwise Electrum will not correctly recognise and recover this seed. Notice from this point, you should now consider this private key as ‘hot’ assuming your Electrum machine is online.
- You can generate a PSBT (Partially Signed Bitcoin Transaction) from Specter-Desktop, sign it with one of your keys (e.g. the Coldcard or Keystone), and then load that PSBT into Electrum via
Load from file. If correctly imported, Electrum will then detect that this transaction has been signed by 1 of 2 required signatures, and present you the opportunity to sign it with the seedpicker paper wallet key.
- You can then save this PSBT file and broadcast it via Specter-Desktop.
Comfortable with the concepts in this step?
Read the advanced considerations that can potentially improve your security here.