@vidister I think if I were putting something that important on a long term storage medium, I might try a Millenniata MDisc Bluray. Their only real disadvantage is the 25 gig limit, and that those have never dropped in price as much as cdr/dvdr's, but they're much more resistant to bitrot. But a paper copy to go along with it is also a good idea for smaller things like keys and two factor backup codes.