The Windows method
Windows can help you protect your folders in so much that only selected users (such as you) can see its contents. You can place restrictions on who can do what with folders, by right-clicking the folder, selecting properties, clicking the security tab and mofifying the contents. (If you can’t see the Security tab, go into Tools -> Folder Options -> View, and un-check “Use simple file sharing”.) Here you can see the properties of a folder on my machine called “Dump”:
Here is where you control who has access to the folder. You may set it so that anyone has access, or perhaps restrict user access on an account-by-account basis, and also whether they can modify, read or even view the folder contents. But that’s all you can do. Since it’s based on user accounts, if you give your account full access to the file, as is usually the case, then anyone logging in on your machine can also access this folder and its contents. There is no real password protection here, other than just ensuring ensuring nobody else can log on to computer. For this reason, the Windows methods is not highly recommended.
The TrueCrypt Method
If you have something you really want to password protect and keep secure, there is a another approach, which I stumbled across recently, and that is the free open-source tool TrueCrypt. Its usage seems counter-intuitive at first, in that you don’t view folder contents in the Windows Explorer sense. Instead, you must first create a file representing your folder to be encrypted, so that if someone tries to look at this file, all they see is a garbled data with no way of knowing what it contains. This file gets “mounted” to a TrueCrypt ‘virtual’ drive, while supplying it with the password needed to access it. If successful, the contents of the file are viewable as another drive on your system.
For example, I might have a encrypted folder file called “C:\stuff.tc”. There is no way anyone else can view that folder unless they install TrueCrypt and enter the correct password. Given that only I know the password, I can mount the file using using TrueCrypt and the virtual drive letter chosen by me (say “L:”) appears, containing all my protected files. These files can be modified or deleted, or new ones added. Once the virtual drive is unmounted, they are hidden again. Nice and simple. And you know that someone won’t be able to access them by simply logging on to your machine, since it’s not tied to any Windows or Linux user account. Obviously you will need to pick a sufficiently strong password, though the encryption algorithms utilized by TrueCrypt are nigh on impossible to crack at this time of writing.
Using TrueCrypt: getting started
Download and install TrueCrypt.
Start TrueCrypt from the Start Menu and click the Create Volume button:
Then choose the first option, “Create an encrypted file container”:
Then choose the “Standard TrueCrypt volume” option. If you think there is possibility that you might be coerced into handing over the password (!) choose hidden:
Click select file for the next stage:
Choose a folder location where you want the encrypted file to reside and click save and then next. Use the default settings for encryption algorithm (AES) and click next:
Specify how big you want the folder to be. Enter the value you wish and click next:
And then choose a good password (>= 7 chars, contains at least one upper/lower/digit character) and click Next: They recommend at least 20 characters, but it depends how determined you need to be.
Nearly there. Now move your mouse as randomly as possible within the Volume Creation Wizard window at least for 30 seconds and click format:
Click exit, and this your encrypted folder created.
Viewing your password protected folder
Once you have successfully completed the steps described above, opening your encrypted folder is easy.
Launch TrueCrypt once again and double-click the volume (highlighted)
You will then be presented with the mapped folder location, as well as its file contents:
Hiding your folders
To hide your folders, just select the drive and click “Dismount” so that it disappears:
Re-mounting your folders
To re-mount, just select the “Select File” button to obtain the necessary “*.tc” file and then select Mount once again.