Bonus points if it has any of the following features:
* certain nodes can store encrypted blobs without being able to decrypt them
* certain nodes can have read but not write access
* certain nodes can have access only to specific subdirectories
* you could set a policy for retaining old versions of files, to use it as a backup system
Is there anything like this out there?
I wonder if IPFS (and eventually Filecoin) would be a good foundation for such a system.