Secret Files (And How to Make Them)

Maybe you want to start a journal, but you don’t want your brother to read it. Maybe you’re corresponding with spies in Luxembourg. We all have our reasons for wanting secrecy. But how do you hide a file on your computer so nobody else can find it?

You could change its properties to Hidden, but that’s not very secure – anyone can go into Folder Options and set Windows Explorer to show all hidden files all the time. Or you could bury it deep in a bunch of folders, but someone could still find it by searching. How do you keep a file really, really secret?

If you’re on a Windows computer, try this. Click Start, then Run. Type “cmd” in the box and click OK. Now you’re at a command line. It should look something like this:

In the beginning was the command line.

(If these screenshots are a little hard to see, you can click them for a slightly bigger view.)

In this command line, the part before the “>” tells you where on the computer you are right now. If you want to go to a different file path, just type “cd”, space, and then the new file path you want, and hit Enter. (“cd” stands for “change directory.”) Like this:

Wonder if they'll change this command to DVD anytime soon?

Once you’re in the place you want, you can use the command line to create a new text file in Notepad. Just type “notepad”, space, and then the name of the file you want to create. It’ll ask if you want to create it. Say yes. Bam, there’s your new text file, open in Notepad.

welcome to my pad

keepin it oldschool

Okay, close the Notepad window.

So far we haven’t done anything too exciting – we just created a regular text file. But now we’re going to hide another text file inside of this first one. How?

Simple. Go back to your command line, and type in “notepad newfile.txt:secret.txt”

Of course, if you called your original text file something besides newfile.txt, you’ll use that file name instead. And your secret file doesn’t have to be called secret.txt. You can call it anything you want. The main thing is to put the plain-view file’s name first, then a colon, then your secret file’s name.


Once again, it’ll ask if you want to create the new file. Say yes. Now you have a new Notepad window open, and it looks like this:

I feel like James Bond already

Notice the file name at the top: “newfile.txt:secret.txt”. We’ve got our secret text file open.

Type anything you want in here. Save it and close it. Now take a look in your folder. What do you see?

nothing up my sleeve...

Just newfile.txt – no sign of its secret sister. But you can always open it again with the same command you used to make it in the first place, “notepad newfile.txt:secret.txt”.

Now, if you do a search on this folder, none of the contents of secret.txt will show up in the results. In fact, if you look at the file size of newfile.txt, it only reflects the size of newfile’s contents. Secret.txt could be as huge as you want, but you’d never know it. (By the way, this technique is called “Alternate Data Streams” – google that if you want to learn more.)

Nothing is 100% secret, of course. If somebody knows what they’re doing, they can track down these secret files too. But you have to know what you’re doing, and you have to be specifically looking for them. I work in IT, and I mentioned this technique to several of my co-workers. None of them had heard of it, or knew how to find the hidden file.

One word of warning: if someone deletes newfile.txt, then secret.txt will be gone too. Just so you know.

Did this make sense? If you tried it, did it work? Anybody have any questions?

Do you think you’d ever use something like this?

5 responses to “Secret Files (And How to Make Them)

  1. I’m not sure I’d ever use something like this, and I haven’t tried it at the moment (Maybe later). However, it’s certainly interesting to learn about. And gathering data is almost never a bad thing, because there is the chance that I can use this data somehow.

  2. how to show secret files if you don’t know the name of files

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