But that's still detached from the actual physical object. I'm thinking you'd want a physical certificate with a verifiable signature, which would be easy if we

But that's still detached from the actual physical object. I'm thinking you'd want a physical certificate with a verifiable signature, which would be easy if we have the relevant public keys. Or equivalent, something like a tiny QR code on the actual physical thing that can be scanned to verify the details + their authenticity. Digital stuff is blurrier but actual physical possession of an item is the only absolute way to determine its owner at a specific point in time, all contracts be damned.