How Stream Read Restrictions work?

Question

Enterprise nodes can use read-restricted streams, in order to publish and retrieve data that is only visible to nodes with the appropriate permissions.

The on-chain streams full data is stored inside the blockchain which every node has a copy of. So the "hacker" without Read  permission can read streams from local disk.

Can you explain the principle of "Stream Read Restrictions"?

Thanks.

Answer 1

Read-restricted streams do not use on-chain data, they use off-chain data. On the chain there is only a salted hash, which can be used to confirm the underlying data is valid but not to reproduce that data. The data itself is delivered separately over the peer-to-peer network, encrypted end-to-end in transit, and only delivered to nodes that can prove they have stream read permissions by signing their request.

For more information about off-chain stream data and its implementation on MultiChain, please see this blog post:

https://www.multichain.com/blog/2018/06/scaling-blockchains-off-chain-data/

The first three parts of the 'So what’s next?' section near the end talks about some MultiChain Enterprise features.