[Latty]

I think the parent post was asking where someone would securely store a hardware device like a yubikey that, for example, contains the only copy of a root key—as opposed to using such a hardware device as part of a security system.

[tialaramex]

In a safe? Buy a half-decent one.

You should align your storage choice to your contingency plan. For a lost root your contingency plan should involve distrusting and replacing the hierarchy underneath the root. To the extent that you wish to avoid executing the plan, buy a better safe so you are less likely to need the plan.

It is OK for your contingency plan to include "Go bankrupt and cease to exist" if you are any sort of corporate entity.

[Latty]

I'm a bit confused by why you responded to me with this.

"Installing safes onsite and self monitoring" was literally the example given by the person asking for other suggestions.

[tialaramex]

Sorry, probably the tangle of threads caused me to disconnect that from your response, as you say my response is useless in light of this.

[ghaff]

I would say nowhere. Even in a reliable safety deposit box that may not exist or be convenient, the hardware can fail. And actually the odds of that are almost certainly greater than your safety deposit box being breached.

[Latty]

I see your point that hardware keys can fail, but that is a completely separate issue—print it out and shove that paper in there as well, redundant copies in multiple locations, etc... it is just a standard backup problem. The hardware key is about ease and safety when you are using it, not as some perfect storage.

In any case, the issue of securing something that you only want to use in extremely rare cases is still an issue—"nowhere" isn't a solution to that problem, although I can see the argument that hardware keys aren't the best choice of storage medium (although as an efficiency measure it could be useful to have one in there as well so you can go quickly if it works).