I'm aware of the expiration date, but haven't been able to understand the embedding or how the pairs of codes may be "hash validated" in some way, which means t

I'm aware of the expiration date, but haven't been able to understand the embedding or how the pairs of codes may be "hash validated" in some way, which means that this is a one time use for me unless I can either generate them or access the nvram on the system. Any insights? How did you find the embedding?