I'm thinking of a blockchain where the ledger is public read (for verifications) and write-constrained. How can you verify the.legitimacy of the introduced data

I'm thinking of a blockchain where the ledger is public read (for verifications) and write-constrained. How can you verify the.legitimacy of the introduced data? Probably some other tool. But it being federated across countries would have the nice property of non-gatekeeping. There are politics in play, but if the UN is possible, só is such a system. This is all just my theoretical assessment, anyway. And I agree that other standards and toolchain is necessary to add value. Blockchains don't do KYC nor identity verification and a lot of other things.