Blockstream has released version 3.5.0 of its desktop wallet application, with new air-gapped transaction signing for its Jade hardware wallet as the update’s primary feature.

The software now allows users to connect to and unlock a compatible Jade device by exchanging QR codes between the computer display and the wallet’s camera. 

The process, called Jade QR Connect, provides an alternative to connecting the hardware wallet through USB or Bluetooth.

Air-gapped signing is available for descriptor-based watch-only wallets. 

Users can monitor balances, generate receiving addresses and prepare transactions in the desktop application while keeping Jade disconnected. 

Transaction information is transferred to the device by QR code, signed on Jade and returned to the app through another QR exchange.

Blockstream describes the process as a fully air-gapped workflow because the hardware wallet does not require a direct connection to the computer. 

This is intended to reduce the device’s exposure to threats originating from an internet-connected machine. 

Users must still verify transaction information on the hardware wallet and follow appropriate security practices.

The update also supplies Jade with 32 bytes of random data generated by the host computer during setup or unlocking. 

According to Blockstream, this supplements the entropy already produced by the device from sources including its hardware random-number generator, sensors, and camera.

Version 3.5.0 separately introduces beta support for sending and receiving Bitcoin over the Lightning Network from within the desktop app. 

The Greenlight-powered feature is limited to Bitcoin mainnet software wallets and does not support BIP39 wallets.

New swaps between Bitcoin and Liquid, including Liquid Bitcoin transactions using Lightning, were temporarily disabled because of a service interruption. Blockstream reported that existing funds were not affected.

Other changes include a simplified receive-address process, revised transaction result screens, code-signed Windows wallet libraries, and smaller architecture-specific installation files for macOS.

Legacy multisignature nLockTime and recovery-email functions have also been restored.

The Blockstream App is available for macOS, Windows and Linux. The company followed version 3.5.0 with a 3.5.1 patch containing stability fixes.