Multi-sig on Bitcoin with AirGap via Nunchuk
Multi-sig is one of the best ways to enhance the security of your assets. With the addition of the Nunchuk wallet, AirGap users can now create Multi-sig on Bitcoin. Let’s see how -
AirGap is an open-source, free-to-use solution where users can turn their spare device into a cold wallet. This setup involves two devices — one with the AirGap Vault (which is kept offline) and your everyday phone with your favourite hot wallet (MetaMask, Specter, imToken, AirGap Wallet, etc). Users can initiate transactions via their hot wallets and sign in with their AirGap Vault. Communication happens via QR codes.
AirGap users can create Multi-sig wallets through third-party providers. In the past, AirGap supported Multi-sig creation on Tezos and Ethereum (and other EVM-compatible blockchains) only; however, with Nunchuk, AirGap. Now supports Multi-sig on Bitcoin.
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Important: Changing the Derivation Path for Multi-Sig with Nunchuk
When setting up your AirGap Vault for multi-signature transactions using Nunchuk, it’s essential to adjust the derivation path from the default setting to ensure compatibility and functionality.
Why Change the Derivation Path?
The original derivation path m/84'/0'/0'/0' is designed for single-signature wallets utilizing native SegWit addresses (Bech32). While this format offers lower fees and improved transaction efficiency, it does not support the multi-signature capabilities required for using Nunchuk effectively.
For multi-signature wallets, you need to change the derivation path to m/48'/0'/0'/2'. Here’s why this adjustment is necessary:
- Compatibility with Multisig: The path m/48'/0'/0'/2' aligns with BIP48, which is specifically structured for multi-signature wallets. This change allows your wallet to generate the appropriate keys and addresses needed for multisig transactions.
- Address Type: The new path directs the wallet to create native SegWit multisig addresses (P2WSH). These addresses, starting with bc1, are optimized for transaction efficiency and security, making them ideal for use with Nunchuk.
- Future-Proofing: As Bitcoin evolves, using a derivation path that supports multisig and newer address formats prepares your setup for future upgrades and features, ensuring you can take full advantage of the Bitcoin ecosystem.
How to Change the Derivation Path?
- Turn on Advanced mode in Vault Settings.
2. Open your desired Secret and tap on the 3 dots in the top right corner. Then, Tap “Add Account”.
3. Choose Bitcoin SegWit and scroll down to the bottom of the page. Toggle the “Advanced Mode” on and change the derivation path to m/48'/0'/0'/2'. Hit Create.
4. That’s it. Now, you have successfully created a BIP-48 compatible account for Bitcoin. Now you can make a multi-sig with it.
Step-by-step guide to creating a Multi-sig wallet with AirGap via Nunchuk
This guide is for those who have already set up AirGap. If you are new to AirGap, follow this guide to get onboarded to AirGap. Make sure you also download Nunchuk app. It’s available for iOS, Android and Desktop.
- Open Nunchuk app and go the Home Screen. First, we need to add a signer Key. Tap on the + button.
2. Select Add an AirGapped Key. Read the instructions carefully and tap Continue.
3. Now, you need to get the Key QR code from AirGap. Open AirGap Vault app and select the secret that you would like to use. Then select your desired Bitcoin account. Make sure you only use the BIP48 account (as explained above) for creating a Multi-sig on Nunckuk.
4. Now, you’ll get a QR code, Scan that QR code with Nunchuk app by tapping on Scan QR button. Then, enter the desired name for the key.
5. Now that you have added one key, add all other keys that you require. Note that these keys will be the member keys in your multi-sig wallet. Here, we will import three keys to set up a multi-sig wallet.
6. Now that all the keys have been paired, we need to create a multi-sig wallet configuration. To do that, click on + icon against “Create Wallet’ Section on the home screen. Then select “Create New Wallet” and then again select it in the popup. Choose a name for your wallet configuration.
7. Now, choose the member keys. Set the number of required keys to sign a transaction. This refers to the minimum number of signatures needed to authorize a transaction or make changes to the wallet. After that, review your wallet and hit Continue. If you want you can also save your wallet configuration in case you would like to import it in the future.
8. That’s it. You have successfully created a multi-sig wallet. Now, you can start making transactions with it.
Make a transaction with your Multi-sig Wallet
Make sure you have deposited some BTC in your new Multi-sig wallet. If you want to purchase it, you can do it on Mt. Pelerin.
- From the home screen, open your wallet. Tap on the Send button.
2. Enter the amount that you want to send. Then, enter the recipient's address. You can also scan the recipient’s address’ QR.
3. Now, you need to sign the transaction. As we have used the 2 of 3 Multi-sig setup, we just need 2 signatures for the transaction. Tap on sign button against your desired member key. Then select Export transaction> Export via QR.
4. You’ll get a QR code to scan. Open AirGap Vault and tap the Scanner button below on the home screen. Scan the QR with Vault. Select the account which is linked to Nunchuk.
5. Sign the transaction after verifying the details. You will get a QR code.
6. On Nunchuk app, tap the “Import signature” button below the QR code. Scan the QR code provided by Vault with it. Again, verify the details and tap Broadcast Transaction.
7. Now, you have successfully signed the transaction from one key. Time to do it with the other one. Follow the same steps and sign the transaction from the other key. After it’s ready to broadcast, tap “Broadcast Transaction.”
8. That’s it. You have successfully signed your first transaction on your new Multi-sig wallet.
Level up your security with AirGap Knox
To celebrate the partnership, we are announcing a flat 40% discount on AirGap Knox. Knox allows you to go one step further, enhancing AirGap Vault’s security. Knox completely disables all sorts of communication from your device on a deep system level. If you have an Android device that’s Android Enterprise recommended, you can opt-in for Knox.
Use code — Nunchuk on AirGap Shop to get flat 40% off on Knox. Offer valid till 2nd October 2024.
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