Access Control in a Blockchain

[Spacebar96]

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?

[1715252976]

1715252976

[Charles-Tim]

I do not know how different blockchain would be, but as for bitcoin, it is a public ledger that anyone can just make use of blockchain explorer to see transaction records, nothing hidden about it, but just that what is already existing on the blockchain as valid would be highly difficult to alter which can only occured during 51% attack.

How other blockchain is designed would be different.

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?

Like bitcoin blockchain that requires 400 gigabyte, there are 2 terabyte of SSD or HDD that are existing and higher ones are coming in the future. Medical record would even need lesser memory space.

[LoyceV]

Imagine I had a Blockchain with all of a nation's citizens' medical records recorded in it.

First: This is a TERRIBLE idea!

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?

The basics of access restrictions includes not giving access to people who shouldn't have access. That means don't share all data with everyone.
Other than that, you could use PGP to encrypt all the data, but it's still a terrible idea.

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?

How is my car meant to have enough power to fly to the moon?

[decodx]

I agree, in my opinion this wouldn't be a good use case for blockchain technology. Medical records contain sensitive and personal information that, if made public, could be used to harm individuals. For example, an individual's medical records could be used to blackmail them or discriminate against them. A blockchain is a publicly accessible, distributed database. This means that anyone with access to the internet would be able to view all the data on the blockchain. This would compromise the privacy of the individuals whose records are in such a database. While the blockchain is designed to be secure, it is not completely private. As such, I don't think that a blockchain would be appropriate for storing  sensitive data like medical records. I think that it would be much safer to store those records in a centralized database, where only certain individuals have access to them.