question: data usage without online account

[scheunengeist]

(using 2.1.1 from the play store)
I've been playing around with encdroid a bit, creating a small encfs volume on my phone. By chance I noticed that within half a month the app used up 16 MB of mobile data volume and ranked second in data usage after my browser. I'm not using Dropbox or any other online account.
This is kind of disturbing for an app that I could potentialy trust sensitive data to, and I'd be thankful if someone could shed some light on what that data usage might be.
Thanks in advance.

[Kamul-PL]

It's too bad that there's no answer for such an important question. Security and privacy is especially important in applications like Encdroid. Maybe someone with knowledge necessary to check that could write some explanations here?