I found this post from a year ago, and it never got answered. I'd also like to know the answer.
The basic question is, When using our own private encryption key, are filenames still visible at the idrive server side?
The previous post with T&C's above seems to suggest that filenames are not encrypted at the point of storage and therefore allows for potential unauthorised access to see what files are being stored (even if they can't be opened).
bfn.
S.