QR Code Signing

QR code signing is a method of transferring transaction data between an air-gapped device and an online interface using visual data encoding. The online interface generates a QR code representing the transaction details, which is then scanned by the offline device.

The offline device signs the transaction and displays a new QR code containing the signature, which the online interface then scans to broadcast. This method is highly secure because it creates a unidirectional data flow that does not require physical connections like USB or Bluetooth, which could potentially leak data.

It is a preferred method for hardware wallets that prioritize air-gapping. By using optical data transfer, users can visually verify the data being signed, adding a layer of transparency to the process.

This protocol minimizes the attack surface by avoiding standard communication protocols that could be exploited.