You’re on point except for one big difference: a block chain is distributed. I don’t think it is foolproof, as no tech really is. But the concept seems to sign

You’re on point except for one big difference: a block chain is distributed. I don’t think it is foolproof, as no tech really is. But the concept seems to significantly raise the cost and complexity of an attack to compromise it. The simplest way I can imagine doing it is - spoofing network requests from the party trying to verify something, or routing that request to a compromised node. I will make a guess that networking equipment in a govt. setting can protect against a low level attack. Disclaimer: I take a passive interest in this space but have never studied or implemented a block-chain application.