Blockchain and anonymous data inside the chain [duplicate]

Question

A Blockchain is often said to be a log of all transactions that were ever verified on a network.

I understand that therefore a purpose could be to make sure that the records are not altered. If they would, the chain would fail by its construction.

However, what do you do when you have sensitive data that you want to store in these transactions? The reason I am asking is because the Blockchain being a Distributed Ledger, everyone has access to view all the transactions/chain.

Use case example: bank transactions

A bank could launch a Blockchain to make sure that the transactions of their clients are irreversible recorded. However, these transactions might contain sensitive information (like the details of their client). When a new block is created, the entire Blockchain is validated, meaning that the person who is creating the transaction has access to the whole chain and thus the details of the client in the previous transactions.

What is then the use case and how do people look at it this type of problem from their perspective?

Answer 1

However, these transactions might contain sensitive information (like the details of their client).

Bitcoin transactions simply do not contain sensitive information, they need no other information other than the amount and the receiver, meaning that the publicity of it is of lesser concern. There was still implicit privacy issues in Bitcoin, but you avoid any issues with personal information being stored in the chain by just simply not doing anything that would cause this information to be included.

Answer 2

Bitcoin blocks do not store any sensitive information. They store transactions where each transaction is composed of one-or-many inputs and one-or-two outputs. Inputs and outputs are simply public addresses.

If you can identity addresses, then you might be able to discern some sensitive information. But the blockchain does not store any personal information.