Confidential information in blockchain

Question

How can we possibly stored sensitive information in chains, like company name, address, etc.?

Answer 1

You have two main options for how to do this in transaction metadata:

• Store only a hash of the information in the blockchain, e.g. using sha256(). This notarizes/locks down that information without revealing it immediately to all blockchain participants. (It's the same idea behind services like http://proofofexistence.com/)
• Use some kind of encryption to embed the data in the chain, so that it's all in there, but is only visible to select participants. Any encryption method can be used because its output can simply be embedded in transaction metadata (see the 'Getting Started' page for an example of how).