This is for all who have encountered the Blank Encryption Key dilemma. First off, I have to say I don’t know how this works, but it worked for me.
Go to File Editor
Click on “the Gear”/Settings
A drop down menu will appear
Scroll down to the last item “Generate UUID”
A large Hexadecimal number will appear in the Editor Box
Highlight that number and copy it
Go back to Settings, Devices and Services
Click on the ADD button of the Home Assistant Voice preview edition entity
One of two things will happen
The HAVpe will not request an encryption key
Proceed with the process of adding the device
Or it will again request an encryption key
Paste the UUID into the encyption key box
Proceed with the process of adding the device
I hope this works for you and others in this and similar situations.
Peter