I am looking for a way to make a set of files only able to be read when a USB key is plugged into the system. For example, if I have FILE A on my C drive and I try to open it, it will say something like "Please insert key" (The "key" being a USB drive) Once I plug the USB drive into the computer and try to open that file, it functions normally.

It's a bit like Predator, but instead of locking the whole computer when you remove the USB drive, it only locks the files. Further, I would like this "locked" attribute to exist across systems, so that if anyone copies the files, they will not run on any other system unless they have the "key".

I worked at a company before that had such a system in place, so I know it's possible, I just have no idea how they did it.

Basically, I think what I'm trying to do is encrypt the files and put the key-file to decrypt them on the USB drive.

Any help would be much appreciated!


2 Answers 2


TrueCrypt seems to offer the ability to use a key file with its encryption.

***As a major disclaimer TrueCrypt technically is no longer supported and may be insecure.

Here is a guide that you can use to add a keyfile to that encryption. You could store a key file on a USB and use that in addition to a password. There might be a more automated way to do this via detection of a USB and search for a filename but this is pretty close to what you want I think.

  • 1
    The audit of TrueCrypt discovered (six months after your reply here) that it was not maliciously compromised. At worst, there were some honest developer mistakes which are now out in the open. As you point out, it's no longer maintained, and VeraCrypt is its sucessor.
    – Omniwombat
    Commented Mar 15, 2016 at 20:51

Look into GoldKey or Yubikey. I know for fact that GoldKey has something similar to what you want, they call it a goldkey vault. Yubikey probably has something similar, but I'm just not as familiar with their products.

Hope that helps.

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