[Cryptography] unique system ID

[John Denker]

On 11/28/2016 02:30 AM, John Gilmore asked for:

>  an appropriate way to pass a system-unique seed (that
> doesn't change from reboot to reboot, but which makes this system
> unique from every other system or VM that was installed with identical
> OS software)?

The standard approach is:

On the machine of interest (virtual or non-virtual)
  :; dmidecode -s system-uuid

On the host, when hosting a virtual machine:
  : host;  if ! test -r guest.uuid ; then uuidgen -r > guest.uuid ; fi
  : host;  qemu-system-x86_64 -uuid $(cat guest.uuid)

If that's not good enough, please clarify the question.