I'm not talking about physical verification but the idea that having a public ledger of each countries gold would add transparency. Whenever gold is moved it would be reflected on the ledger for all other central banks to see.

The problem with the gold standard era was countries, particularly the USA, claiming it had a lot more gold than it did and you just had to take them at their word. It wasn't until Charles de Gaulle called them out and demanded the physical transfer.

It can't.