Oh please, just like 1024 bit PGP keys were "unbreakable in the foreseeable future", back in 2001. Or how 640 kB ought to be enough for everybody. Yes, and at that point I would lose mobile access and I could also store the data on other untrusted servers like Dropbox and the many other options. Don’t get me wrong, I’m not planning to save any highly sensitive data via Bittorrent Sync, but I still don’t want random people to go through my family pictures and random documents with almost no effort sometime in the future. An encrypted peer under my control with a long, self-generated secret seemed like the perfect tradeoff between security and convenience for me, but on a second thought, maybe I am stupid for trusting such a tight-lipped closed-source program with security/privacy sensitive features in the first place.