Encryption Dropbox – Individual File Encryption on Dropbox


I'd like to set a single directory inside Dropbox in which files are encrypted on a file-by-file basis.

At the moment, I use a 2Mb Truecrypt container inside my Dropbox which I then have to mount manually, access/change the files within, then unmount manually. At that point, the entire 2Mb uploads to Dropbox. This is a pain for a number of reasons :

  1. Dropbox sync will only occur when the Truecrypt container is unmounted, because Dropbox only syncs files that aren't locked and mounting a container locks it.
  2. A single byte change to one file inside that container results in the whole 2Mb being uploaded again.
  3. It doesn't scale – I was originally using a 10Mb container, but obviously the bigger the container, the longer it takes to sync when it's unmounted.

I was wondering if I can somehow use LUKS to implement file-by-file encryption to get round the "container" issues.

Best Answer

I have two methods in place with my Dropbox.

The first is using CryptKeeper Install CryptKeeper. This creates and mounts enc_fs encrypted directories, independent of the Ubuntu implementation of Private.

Instructions by Scaine on using Cryptkeeper are here: How can I do individual file encryption on Dropbox?

CryptKeeper screenshot

The second is symlinking selected directories from ~/.Private into the Dropbox directory. This automatically uploads (and syncs) the encrypted versions of files normally situated in ~/Private. This assumes you have set up the encrypted Private directory! It can also be initially tricky to find the correct one to link.

Ecryptfs screenshot

While neither of these is strictly encryption of a single file, as both use a container of sorts, both methods scale easily as only changed files are uploaded.