Encrypting drives is a big step in the right direction for protecting our digital lives, but there are times when we need an extra twist. That’s where VeraCrypt comes in with its support for hidden volumes, which basically work as secret disk units inside an already encrypted environment. Want to know more…?

So, You Want a Secret Disk Unit…

The idea isn’t exactly new. When we were kids, many of us felt like hackers for using the hidden attribute with pure ‘attrib +h’ in MS-DOS, and there were always those who ruined installations that way (raises hand), but now we have a better idea of how to hide data, and most importantly, we have better tools.

One of them is VeraCrypt. Heir to the classic TrueCrypt that disappeared in 2014, VeraCrypt has reached a notable level of maturity, but what interests us most is its hidden volume feature. Long story short, this allows creating an encrypted volume inside another. Thus, the user can provide access to the first under extreme situations, while hiding/denying the existence of the second.

How to Create a “Secret Disk Unit” with VeraCrypt
The VeraCrypt interface

Obviously, this strategy is not perfect, and the official VeraCrypt documentation acknowledges it. Its section “Security Requirements and Precautions Pertaining to Hidden Volumes” is fascinating and deserves careful study, but if you’re just looking for the basic information to create the equivalent of a secret disk unit with VeraCrypt, you can start here.

Creating a Hidden Volume in VeraCrypt

How to Create a “Secret Disk Unit” with VeraCrypt
The process is long, but simple
  • With VeraCrypt already installed on your system, click on “Create Volume”, and then select “Create an encrypted file container”.
  • In the second section, choose “Hidden VeraCrypt volume”, followed by “Normal mode”. This will create a conventional encrypted volume, and then give shape to the hidden volume inside it.
How to Create a “Secret Disk Unit” with VeraCrypt
You must choose Hidden, but first you’ll create the outer volume
How to Create a “Secret Disk Unit” with VeraCrypt
Since no previous volume exists, Normal mode is best
  • This is where VeraCrypt asks for the location and name of the file to create the new volume. A positive aspect is that VeraCrypt allows using fake extensions (for example, .dat), or ignoring them entirely. Don’t save the history.
  • In the next step, VeraCrypt will ask you to define the encryption type (AES/SHA-512 is a good combo), the size of the conventional volume, and its password. The size is up to you, but you should use a strong password for all cases. VeraCrypt recommends a minimum of 20 characters.
How to Create a “Secret Disk Unit” with VeraCrypt
The volume needs a location. I recommend changing the extension to something more generic; VeraCrypt will have no problem reading it.
How to Create a “Secret Disk Unit” with VeraCrypt
The minimum volume is 340 kilobytes, but we used 128 megabytes in our test
How to Create a “Secret Disk Unit” with VeraCrypt
Even if it’s the initial volume, the password must be strong
  • VeraCrypt will need to format the new volume and obtain some “noise” from the movements you make with the mouse. Once the bar reaches its full width in green, the program is ready to continue. Leave the other options on FAT, Default, and Full Format.
  • After formatting, VeraCrypt will recommend opening the conventional volume (you can use the Open Outer Volume button) and copying some files into it that look private. After completing that task, a click on Next will take you to the creation of the hidden volume.
How to Create a “Secret Disk Unit” with VeraCrypt
A bit of entropy for a better result
How to Create a “Secret Disk Unit” with VeraCrypt
Open the initial volume and load some files into it. You know, something “confidential”.
How to Create a “Secret Disk Unit” with VeraCrypt
The hidden volume uses its own encryption
  • Creating the hidden volume requires a process similar to the previous one. You must specify the encryption type, its size (which will be smaller than that of the conventional volume), a new password that must be different from the previous one, no matter what, and format.
  • Now, if you plan to save more files in the conventional volume, you cannot mount the hidden volume directly. First, you’ll need to go to the Mount Options menu, select the “Protect hidden volume against damage caused by writing to outer volume” function, and enter the hidden volume’s password. If you don’t do this, you could damage the hidden volume when placing new files in the conventional volume (a classic accidental overwrite problem).
How to Create a “Secret Disk Unit” with VeraCrypt
If you want to save additional files in the initial volume, you must change something during mounting
How to Create a “Secret Disk Unit” with VeraCrypt
If you don’t protect the hidden volume section, you could lose its data
How to Create a “Secret Disk Unit” with VeraCrypt
VeraCrypt presents a very important warning about this
  • The steps to mount the hidden volume are the same as for a standard volume: find the file, select a drive letter, and click on Mount, BUT, enter the hidden volume’s password. The rest is a matter of using the file explorer to save data inside it.
How to Create a “Secret Disk Unit” with VeraCrypt
With the hidden volume mounted, we are ready to save information…

How Well Does This Work?

Inevitably, the final answer is “it depends”. Every security system is only as strong as its weakest link, and the “secret disk units” of VeraCrypt are no exception. If the user makes mistakes or doesn’t follow the developer’s recommendations, they can be exposed despite the hidden profile of these volumes.

However, it’s still an interesting practice, and protecting our data is never a burden. On the contrary, the idea is to incorporate more security solutions, and VeraCrypt offers an excellent opportunity here, with open source software (though not everyone agrees), and free.

Official site and download: Click here