Getting Started

Krux is open-source Bitcoin signing firmware for devices with the K210 chipset; also known as a hardware signer.

Signing operations in Krux are done offline via QR code or via SD card using the PSBT functionality. You can create/load your BIP-39 mnemonic, or import a wallet descriptor, and sign transactions all without having to plug the device into your computer (except to initially install the firmware). It reads QR codes with its camera and outputs QR codes to its screen, or to paper via an optional thermal printer attachment.

Krux runs offline, and therefore never handles the broadcasting part of the PSBT transaction. Instead, you can use Krux with third-party wallet coordinators to broadcast transactions from your online computer or mobile device while keeping your keys offline. Krux was built to be vendor agnostic and works with many popular wallet coordinators, including: