storing private data in Filecoin (is it safe?)
Assuming you’re encrypting with a currently secure symmetric cipher (like AES-128), then I guess you’re making a bet that AES will remain unbroken forever, or for the time period that you need the data to remain confidential (which usually isn’t forever – presumably we all plan to be dead at some point in the future). But you are making the same bet every time you enter private data into an ssh or https session, right? I don’t see any difference there.
be sure of data durability and availability
I’m wondering about this one also. How can a storage client verify – independent of the PoRep mechanism in the protocol – that the data is still retrievable? The only way I can think of is to do periodic trial retrievals, each time making sure you get back your data unmodified. That will cost some FIL in the retrieval market, but I don’t see any other way.
Interested in others’ answers as well!