First of all, excuse me if this is not the section to ask.
I'm trying to find out what information can be encrypted inside the blockchain, i.e. should all the information written in the blocks be (compulsorily) unencrypted? I've read some research articles about frameworks that allow to encrypt information, so I deduce that certain information can be encrypted. Is there anyone who can help me on this topic or do you know where I could look for more reliable information?
In short: can information be encrypted? If so, which part can be encrypted?