[syslinux] Verify contents before boot?

[Bret Schuhmacher]

I see there's a memtest on the Linux discs I've created... would it be
possible to put another program in place (a module, perhaps?) that can
calculate a hash using a certain algorithm (i.e. SHA512 or similar) to
validate and print out the hash of the boot ISO before booting it?  The
integrity of the ISO is absolutely critical.

Thanks,

Bret