20 April 2012

120. Using truecrypt with dropbox

This is not some fancy, automatic solution. This is for people who may not be familiar with truecrypt and how to use it. To most people this will be obvious.

Basically, one way in which you can use truecrypt is to create a file which, when mounted, acts like a device/filesystem. This container is encrypted and the strength of encryption depends on your key or password.

As a solution it also suffers from slow initial syncing.

Setting it up is a piece of cake:
1. Install truecrypt.
Get the correct version e.g. "Standard x64" from http://www.truecrypt.org/downloads.

Install by extracting the file and executing it:
chmod +x truecrypt-7.1a-setup-x64
sudo ./truecrypt-7.1a-setup-x64

2. Start truecrypt and click on Create Volume

Select encrypted file container. The other option is more useful  if you have access to the hardware.

Using a Hidden truecrypt volume means you pay a space penalty, depending on how you distribute the space between the two volumes.

Select location and filename

Pick an algorithm. I don't know much about this, but using a cascade sounds reasonable. I guess there are performance penalties though.

Be aware that the container file will take up all this space -- whether it's empty or not.

 3. Use the container file.
Click on Select File, then mount. You typically need to supply both the container password and your admin password.

This is what the inside of the container file looks like.
And this is what the dropbox folder looks like


  1. Well, thank you for your post. I have only one question now. One simple question, hoping for one simple answer.

    May I create a container with TruCrypt, move my Dropbox folder into that container, and enjoy client side encryption without hindering the Dropbox features?

    Yes or no would be great, if possible.



    1. Short answer: no idea.
      Longer answer: I don't think so. A container is ultimately just a file. Can you mount a folder inside a file? Nothing prevents you from trying though, and I may well be wrong.

  2. Replies
    1. Ben,
      to me it looks like it mounts the dropbox folder inside a truecrypt container, which is exactly what Mike above asked about.

      From a personal point of view, whether or not this provides any advantage in terms of safety is debatable and depends on who you're protecting your files from. It should certainly protect your files from other users on the same local system, BUT as far as I can see it means that the files on the dropbox servers are not encrypted. Using 'my' (fairly obvious and not very elegant) method they are encrypted at all times.

      Again, I make no claims towards being an expert on this, and each approach has it's merits, depending on in what direction your paranoia is pointing ;-)