>Now back to the original question of whether this could be done with a central database instead of blockchain. The answer is "of course", but now even the who and the what is potentially suspect IN ADDITION to the virtual-physical mapping problem.
I don't really understand that. The "who" can be authenticated using digital signatures (say, a PGP signature for instance, or a certificate signed by the authority in change). This is exactly the way a blockchain would work, making a transaction means signing it with your private key. As long as your private key remains private nobody can impersonate you (but that's not revolutionary blockchain technology, that's goold old seventies asymmetric crypto technology).
As for the "what" I'm not sure what you mean by that. If somebody (the "who") digitally signs a message or transaction and its contents (the "what") gets modified somewhere along the way then the signature will fail to validate. On the other hand if I get a signed message by entity A saying something that turns out to be false then it's proof that A lied, was compromised or made a mistake.
I don't really understand that. The "who" can be authenticated using digital signatures (say, a PGP signature for instance, or a certificate signed by the authority in change). This is exactly the way a blockchain would work, making a transaction means signing it with your private key. As long as your private key remains private nobody can impersonate you (but that's not revolutionary blockchain technology, that's goold old seventies asymmetric crypto technology).
As for the "what" I'm not sure what you mean by that. If somebody (the "who") digitally signs a message or transaction and its contents (the "what") gets modified somewhere along the way then the signature will fail to validate. On the other hand if I get a signed message by entity A saying something that turns out to be false then it's proof that A lied, was compromised or made a mistake.