I believe you can test this when you use the recovery media ISO file and direct it to the backup files.  It should then prompt you for the encryption key for the backup files used in the job.

Hopefully this helps too - Data Encryption - Veeam Agent for Microsoft Windows Guide

Data Decryption doesn’t require you to enter a password if you use Encryption on the same device as where you Encrypted, which it appears you are doing, as noted in the Decryption section of the Guide here. Decryption happens “auto-magically” 

I don’t think I fully understand your question about the Backup Job. You are wanting to move or copy the job to another computer? From the User Guide , I didn’t see anything referencing being able to move or copy a VAW job from one computer to another, or how to “export” then “import” a job.

I found this Configurator Reference , which may allow you to do what you’re wanting. I believe you’d need to install VAW on another computer, then you can import the XML file to:
C:\ProgramData\Veeam\Endpoint\!Configuration\ . BUT...I recommend you test it out before doing so on your “main” (prod) computer first...if you have a test device to do so on.