In December of 2014, the following blog was written:
The post notes two security implementations that were planned. The first is being able to set a minimum shard entropy to ensure files on my server are sufficiently encrypted. The second was registering with a shard graylist to yank suspicious shards from my server.
I don’t recall seeing a setting for either of these two things. They are not mentioned in the FAQ, or in the documentation. I’m curious about their status. Do we have the ability to use this graylist or set an minimum entropy? Were these implemented as part of software upgrades automatically when the system went live? If not, when can we expect an update?
The article you linked is related to the old v2 network. The current v3 network is completely different, and works in a completely different way. That being said, there are no options for greylisting different types of content. The system has no way of knowing what users upload. Each node only holds a small piece of any given file, so to anyone other than the uploader, you are holding random bits of data that could never be decrypted into a usable file. The complete file is simply not on any single storage node.
I am unsure about the uplink settings for encryption. You should be able to find the default encryption scheme somewhere.