https://brave.com/themis/ https://brave.com/themis/ should be a good pointer about how to get an advertisement network that can avoid fraud and report views acc

https://brave.com/themis/ https://brave.com/themis/ should be a good pointer about how to get an advertisement network that can avoid fraud and report views accurately while preserving privacy. The same principles could be applied to a permissioned blockchain that could be used by physicians and healthcare providers.