How do I control read access to stream data?

Question

I read your blog post about stream confidentiality (http://www.multichain.com/developers/stream-confidentiality/) and I was wondering how do I extend this so that access can be taken away in the future? From how I understand the tutorial, once a server has access to the item (via public key encryption), it cannot be taken away since the server can use its key anytime to decrypt. I want to be able to grant access to stream items and also to be able to deny access in the future.

Thanks!

Answer 1

I'm afraid this simply cannot be done in a decentralized immutable system such as a blockchain, because every node has a copy of all the data. So if a node saw the decryption key once, and has a copy of the encrypted data, it will always be able to decrypt it in future. You need a centralized database, not a blockchain, if you want to control access in this way.