So if you have recently moved from the original z-wave implementation in Home Assistant to Z-wave JS, or are setting up a fresh instances, you will need the Z-wave security key. This key is required to communicate with your Z-Wave secure devices (like locks) and without it, you will have to re-enroll your secure devices.
So I made the mistake of not retrieving my key before removing the integration in Home Assistant. I was content to just re-enroll the affected devices, but one of the commenters on the video asked the same question so it got me thinking. I dug around a bit and found the key in my backups.
THIS WILL ONLY WORK IF YOU HAVE A BACKUP
So the solution is to retrieve one of your backed up snapshots and pull the key from there.
I have mind backed up on the Pi itself and also in Google Drive. If pulling from home assistant, you will need to navigate to your instance with a file manager (SAMBA or FTP) and open the /backup folder. That is where the TAR files containing the backups are.
Pull down one of the backup files and extract it (or just open it using something like 7-zip.
Then navigate past the root directory (it is just a .)
Then open the homeassistant.tar.gz file, then the homeassistant.tar. You should then see your /config directory.
Then you will want to navigate to the .storage directory and find the file core.config_entries. This file contains all of the tokens and keys used by your Home Assistant integrations. You will want to Edit this file (or extract and edit it if needed).
Now search for “zwave” under that entry you will see another entry for “network_key”. There should be a series of hex numbers separated by commas.
Finally you will want to copy that entire key between the quotes. Paste that into notepad or similar. Now to convert the key to something that Home Assistant can use, just remove the 0x from in front of each pair, then remove the comma and space.
So in the example above you would take the string: 0xAF, 0xB5, 0xCB and change it to AFB5CB…
Do this for the entire string.
Now head over to your Home Assistant Supervisor Add-ons and open the Z-wave JS add-on.
Finally, click on the Configuration tab and replace the network key with your new one. Press Save and Reload the Add-on. Now you should be able to communicate with your secure devices.
Please note, you will have to wake up the devices before they will communicate with the corrected key.