Steps to register a 2 of 3 multi-sig with Cold Card being the first signing device using a cordinator app
To register a 2-of-3 multi-sig with a Cold Card being the first signing device using a coordinator app, you can follow these steps:
Create a new wallet on your Cold Card device and note down the seed words. This wallet will be one of the 3 keys for the multi-sig.
Install a coordinator app such as Specter or Electrum on your computer or mobile device.
Connect your Cold Card to your computer or mobile device and open the coordinator app.
In the coordinator app, create a new multi-sig wallet and select “2 of 3” as the threshold and “Cold Card” as the first device.
Follow the prompts in the coordinator app to generate the other two keys. These keys can be generated using other hardware wallets or software wallets.
Verify the details of the multi-sig wallet in the coordinator app, such as the receiving address and the transaction fees.
Fund the multi-sig wallet with the desired amount of Bitcoin.
When you want to spend funds from the multi-sig wallet, connect the Cold Card to your computer or mobile device and sign the transaction using the coordinator app. The other two key holders will also need to sign the transaction before it can be broadcasted to the Bitcoin network.
It’s important to note that the coordinator app and the other keys should be kept in a secure location and backed up properly to avoid any potential loss of funds. Additionally, it’s recommended to practice using a small amount of Bitcoin before transferring larger amounts to the multi-sig wallet.