If you want point-to-point with fan-out non-broadcast messaging, email exists already. Using a world-readable publishing protocol and complaining that someone you don't like can read your messages does not warrant sympathy.
I propose buying an island from Canada for winter games and an island from Indonesia for summer games. Islands for crowd and security control. Pay a South Korean corporation to manage the venue and security. Pay the Octopus consortium to manage the access and payment cards.