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TrueCrypt describes itself as “free open-source disk encryption software for Windows Vista/XP, Mac OS X, and Linux”. One of it’s (many) abilities is to create virtual encrypted disks within normal files and access them as if it were real disks. This can be useful when you want mix encrypted and unencrypted files on the same disk; for example on a USB pen drive where you keep private documents but also use to copy files between computers.

The TrueCrypt virtual encrypted disk file (known as a “container”) exists as a regular file on the drive and, when opened using the TrueCrypt program, provides access to the private files held within it.

Earlier versions of TrueCrypt don’t provide an easy way to open these containers; you must first start the TrueCrypt GUI, then browse to the container file and finally enter the password. Later versions have rectified this situation somewhat by offering an “Associate .tc file extension with TrueCrypt” option on installation. However, this tutorial describes a method (for Windows XP) with a couple of further advantages over the TrueCrypt installer’s method.

• Obviously, it works when TrueCrypt has just been extracted from the download archive and not actually installed into the system.
• It automates a few more steps than the standard option to allow the password dialog to automatically and immediately appear when you double click a TrueCrypt container file.
• It works with file extensions other than the default “.tc”.

But first a word of caution: following this tutorial will leave traces on your system that the TrueCrypt software is installed and has been used, thus breaking TrueCrypt’s Plausible Deniability. For most people this won’t be an issue, but please consider this fact in the context of your situation and use of the software before proceeding.

Happy to proceed? Good!

Tutorial

What we will do is set up a Windows file type for the TrueCrypt container extension and have it open automatically with the TrueCrypt program, skipping straight to the password prompt.

Assumptions

1. You are generally familiar with the use and operation of TrueCrypt and have the software installed and working. This is not a TrueCrypt tutorial!
2. You have already have a TrueCrypt container (or containers) that you want to automatically open by double clicking.
3. By default, TrueCrypt containers have a “.tc” file extension and the rest of this tutorial assumes that you have not changed this.

Tutorial steps

1. Open Windows Explorer and select the Tools->Folder Options… menu option:
2. Select the File Types tab and click New:
3. Enter the “TC” extension (or whatever you have changed it to) and click OK:
4. Back in the file type list, select the new TC file type and click Advanced:
   
5. In the Edit file type dialog, do the following:
   • Enter a description of “TrueCrypt Volume”
   • Check Confirm open after download
   • Check Always show extension

   

6. Click Change icon then click Browse and select your TrueCrypt.exe file, wherever you have installed it (C:\Program Files\TrueCrypt\TrueCrypt.exe by default). Choose whichever icon you prefer and click OK:
7. Back in the Edit File Type dialog, click New and another dialog will open.
   In this dialog, enter an action name of “open”, then click Browse and select your TrueCrypt.exe file again (same as in step 6). The path to TrueCrypt.exe will be displayed in the lower text box – append the following parameters exactly as shown to the end of the path with spaces in between.

   /v "%1" /a /q

   What these mean is:

   • /v “%1″ tells TrueCrypt the path of the file you’ve double clicked on
   • /a : automatically mount the volume specified by /v
   • /q : perform the specified action and quit

   Referring to the TrueCrypt command line usage guide, further parameters may be added. Some useful suggestions may be:

   • /e : automatically open a Windows Explorer window for the mounted volume
   • /l x : use specific drive letter “X” for the mounted volume
   • /m rm : mount the volume as removable media (if you’re using a USB key, for example)

   For reference, the complete parameter string I’m using is as follows:

   "C:\Programs\TrueCrypt\TrueCrypt.exe" /v "%1" /l x /m rm /a /e /q

   When you have finished entering your parameters, click OK.

8. Back in the Edit File Type dialog, check everything looks correct and click OK:
9. The file type list should now be showing your new “TC TrueCrypt Volume” type with the icon you selected and opening with the TrueCrypt application. Click Close:
10. Using Windows Explorer, browse to your TrueCrypt container file and double click on it. If everything has gone well, the TrueCrypt password dialog should appear.

If the password dialog does not appear, go back to the Edit file type dialog and check the parameters on the open action. This dialog may be reached at any time by selecting Tools->Folder Options…->File Types and double clicking on the TC file type we have created. You should now be able to open all your TrueCrypt volumes by simply double clicking them.

I find this to be a very convenient shortcut for working with TrueCrypt containers and I hope it’s useful to you too.

John Girvin is an experienced a software engineer and web developer based in Belfast, Northern Ireland. He draws on over 14 years of hard won, real world experience of different projects, clients and working environments.

John is currently working with the Art Technology Group (ATG), developing J2EE based, market leading e-commerce technology.

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