04-04-2013 03:09 PM
The current encryption option for the SD card encrypts ONLY the data contents, and NOT the full structure of the filesystem.
As it stands right now pulling an encrypted SD card from the Z-10 and inserting it into a Windows machine divulges the entire filesystem structure with names and modification dates intact. The data itself is encrypted and the file size padded out to the next 4k size, which appears to be the block size of the encrpytion system.
While this prevents Windows from considering the card "unformatted" and thus randomly offering to destroy it with a single click (which it would otherwise do) the file names, mod times and sizes confer quite a bit of information to a hostile party who comes into possession of the device and its memory card.
Having the choice of that not being the case (as is true for full-disk encryption on FreeBSD and other systems such as TrueCrypt) would be nice, even though it does some with a greater risk of accidental destruction should you insert the card into some other device by accident.