While i research the Blockchain network online. I have some concerns about a certain topic related to blockchain technology. The data storage on each node. Imagine I had a Blockchain with all of a nation's citizens' medical records recorded in it.Each piece of data is broadcast to every user connected to the network. Is there not a method to restrict access to each user's records to those who have permission to access them and their own records only?
How is a person's computer meant to have enough memory to store all of a country's citizens' medical records if the data is saved on each node in a blockchain?