That's of concern but solutions to these problems have been discussed in the original post. This includes: - Have a custom difficulty for every single passport

That's of concern but solutions to these problems have been discussed in the original post. This includes: - Have a custom difficulty for every single passport so that it wont be profitable to extract the private key. Let's say a passport has already mined a block, then it will be twice as difficult for that same passport to mine a second one. - Make it so that 51% of the countries have to collude in order to run a double spend. Now think about the advantages: - No Botnets mining it. - Potentially many more "small" miners (individuals). Not huge mining farms somewhere in China or Island.