BlueWallet 2/3 PSBT Multi-sig: Keystone + ColdCard + SeedPicker

Keystone firmware versions V1.1.1 (BTC-Only) or newer support PSBT Muti-signature functions. Detailed instructions below will explain how to create a 2-of-3 PSBT Multi-signature wallet with Keystone, ColdCard and a SeedPicker as 3 participant co-signers. Bluewallet V6.2.0 (or newer) will be used as a watch-only wallet.

I. Preparation

1. Firmware version V1.1.1 (BTC-Only) or newer running on Keystone Essential or Pro models.

(Please read How to upgrade firmware for more details.)

2. ColdCard upgraded to firmware version V2.1.0 or later.

3. http://seedpicker.net/ run on an offline PC/Mac.

4. Smartphone with the BlueWallet V6.2.0 or later downloaded.

5. Log in to your iCloud Drive on an online PC/Mac.

Note：If you are using an Android based system, you can choose alternative cloud storage applications such as Google Drive. We still recommend saving your data to a local folder on your device, then copying it over with a data cable. This way, the online drive provider won’t see your file or transaction.

6. MicroSD card (≤512GB; Default FAT32 format).

Tips: Keystone can format microSD cards to FAT32. (Tutorial)

II. Creating a 2/3 multisig wallet with Keystone, ColdCard and seed picker (http://seedpicker.net/)

- Export the required XPUB to a microSD card

1. Export ColdCard’s XPUB to a microSD card

1) Insert the microSD card into your ColdCard.

2) [Settings] > [Multisig Wallets] > [Export XPUB].

3) Confirm(√) > save the XPUB of the recovery phrase as a .json file to the microSD card.

4) Take out the microSD card from ColdCard.

2. Export http://seedpicker.net/’s XPUB to a microSD card

1) Insert the microSD card into your PC/Mac.

2) Click [Download] to save the XPUB of the recovery phrase created by SeedPicker as a .json file to the microSD card.

3) After the previous steps, you will receive 2 files in your microSD card.

Let’s check what’s in the microSD card:

- Creating a 2/3 multisig wallet on Keystone

1. Insert the microSD card containing the XPUB of the ColdCard and the SeedPicker into your Keystone, then turn the device on.

2. Navigate the Keystone directory from [Menu] > [Multisig Wallet] > [Create Multisig Wallet] > then Set the “Co-Signers”, “Signers” and “Address Type”, then Press [Confirm] to enter the page for importing the XPUB of the co-signers. You can see the first XPUB has been filled No.1.

3. Select the [microSD card] icon in the bottom right corner of NO.2, then select and open the XPUB file of the ColdCard (e.g. shown as “ccxp-5271C071.json”).

4. Select the [microSD card] icon in the bottom right corner of NO.3, then select and open the XPUB file of SeedPicker (e.g. shown as ‘’seedpickerxp-c5cac506.json”).

5. Select the [Create] button to reveal the QR code (The QR code is used for importing the multisig wallet to BlueWallet).

6. Select the [touch here to export the file with microSD] option > then press [Export]. Save the multisig wallet file to the microSD card to import the multisig wallet to the ColdCard.

- Importing the multisig wallet to BlueWallet and creating the watch-only coordinator

1. Run the BlueWallet app on your smartphone and go to the wallet's interface and select [Add now], then select [Vault], and press the [Import wallet] button.

2. Select [Scan or import a file], then use your smartphone's camera to scan the QR code displayed on Keystone.

3. BlueWallet can now be used as the watch-only coordinator for the multisig wallet.

- Importing the multisig wallet to ColdCard as a co-signer

1. Pull out the microSD card from Keystone and insert it into ColdCard.

2. ColdCard: [Settings] > [Multisig Wallets] > [Import from SD] > Pick the multisig wallet file (.txt) > Confirm(√) and complete the import.

III. Receiving bitcoin to the 2/3 multisig address

You can use receiving addresses displayed by either the Keystone hardware wallet or BlueWallet to receive bitcoin.

1. Keystone: Enter the [Multisig Wallet] on Keystone and touch [Addresses] to display the receiving addresses.

2. BlueWallet: Go to the corresponding wallet and touch [Receive] to display the receiving address.

IV. Sending bitcoin from the 2/3 multisig wallet

Generate the multisig transaction on the watch-only coordinator wallet (Bluewallet) by scanning the unsigned multisig transaction data or exporting the unsigned multisig transaction file to a microSD card (for the Keystone) and iCloud Drive (for the Coldcard).

1. Create a 2/3 multisig transaction on BlueWallet

1) Open the BlueWallet app on your smartphone, then find and select the multisig wallet.

2) Select [Send] to open the remittance interface.

3) Input the receiving address, amount, transaction fees, and notes, and select [Next].

2. Partial signing of multisig transactions with the Keystone

1)BlueWallet: under [Vault Key 1], select [Provide signature] to display the unsigned transaction information in a dynamic QR code format.

2) Keystone: Enter the concerning [Multisig Wallet], then select the [scan] icon and scan the QR code displayed by BlueWallet.

3) Select [Sign], then Enter your password, and then select [Confirm] to show the signed transaction data in QR code format.

4) BlueWallet: Select [Scan or import file] on BlueWallet, then scan the QR code displayed on Keystone to transmit the signed transaction data.

3. Partially sign multisig transactions with ColdCard

1) Log into your iCloud Drive on an online PC/Mac and insert the microSD card into your PC/Mac.

Note: If you are using an Android-based system, you can choose alternative cloud storage applications such as Google Drive. We still recommend saving it to the local folder on your device then copying it over with a data cable. This way, the online drive provider won’t see your file or transaction.

2) BlueWallet: Under [Vault Key 2], select [Provide signature] > [Share] > [Save to Files] > [iCloud Drive] and finally the [Save] save button on the top right corner.

3) Open the iCloud Drive on the PC/Mac and download the unsigned transaction file and save it to the root directory of a microSD card.

4) Take out the microSD card from the PC/Mac and insert it into the ColdCard.

5) ColdCard: [Ready To Sign] > [Select transaction file] > Confirm(√).

6) Take out the microSD card from the ColdCard and insert it into your PC/Mac.

7) Save the partially signed multisig transaction file to the microSD card.

8) Open the iCloud Drive on the PC/Mac, and upload the partially signed multisig transaction file to your iCloud Drive.

9) BlueWallet: Select [Scan or import file] on Bluewallet > select the [+Files] icon on the bottom left and find the partially signed multisig transaction file in iCloud Drive, select it to successfully sign.