How do I upload a key using my Coldcard?

Sign into your account, then click 'Keys' on the left to get started.

Keys are required to create vaults and loans. You will use a Coldcard hardware wallet to upload a key to your account in air-gapped mode.

What you'll need

  • Your Coldcard hardware wallet with its power cord and SD card
  • A PC or Mac with an SD card reader
  • An approved Unchained account

Note on the Coldcard MK4

You can share Coldcard files via a USB connection to your computer, although we don't recommend it. Your computer will recognize the Coldcard as a storage device, like a USB flash drive. We do not support the Coldcard MK4's NFC function at this time.

How to upload a Coldcard key to your account

  1. Follow the guide from the manufacturer to set up the hardware wallet as new and insert the micro SD card into the Coldcard.
    • Coldcard MK4 USB mode: Plug the Coldcard into a USB port on your computer.
  2. Sign in to your Unchained Capital account, click Keys on the left side menu and Upload new key.
  3. Type a name for your key.
  4. Choose Coldcard as your hardware wallet.
  5. Export your XPUB.
    • Coldcard MK3: Go to Advanced > Micro SD > Export Wallet > Unchained.
    • Coldcard MK4: Go to Advanced > Export Wallet > Unchained.
    • Alternative method: Choose Settings > Multisig Wallets > Export XPUB. If you are asked for an account number, enter 0.
  6. Remove the SD card from the Coldcard and insert it into your computer’s SD card reader.
    • Coldcard MK4 USB mode: Find the .json file on your Coldcard's drive on your computer.
  7. Upload the XPUB to the Unchained platform and click Next.

That’s it! You can now use your key to create vaults and loans.

Tip: Practice good key management by reviewing our operational security article.