Part 8/10:
Perhaps the most compelling feature demonstrated is fully air-gapped transaction signing:
- Initiate Sending Funds:
- Using Nunchuk, Bart drafts a transaction to send all available BTC to a recipient address.
- Sign with QR Codes:
The Cold Card Q, in passphrase mode, displays a QR code representing the unsigned transaction.
Bart scans this QR code on his phone using the device’s built-in reader, transferring the transaction data securely without USB.
- Review and Confirm on Cold Card:
The Cold Card then displays the transaction details on its screen.
After verifying the accuracy, he signs the transaction on the device.
- Broadcast the Signed Transaction:
- The signed QR code is scanned back into Nunchuk, which imports the signature.