Secure a folder or file in Windows XP with permissions and encryption

There are often folders and files on your hard drive that should be secure from prying eyes. Microsoft Windows XP Professional has several basic built-in features that make securing data simple.

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Not all data is meant to be shared. Often you'll want to prevent information from being seen by just anyone. Microsoft Windows XP Professional provides several features for securing data. Although the methods are basic in nature, they'll be more than enough deterrent for all but the most determined hacker.

Protecting data from certain users is the situation OptionExplicit faced when he asked for help in TechRepublic's Discussion Center.

How do I secure a folder/directory from being accessed by unauthorized people (from Windows explorer), but at the same time, give access to some programs that need to access that same directory or the files in it? The programs that will routinely access the folders are written in VB.

Solution 1

Windows XP Professional allows you to set permissions for a file or folder from the properties dialog, which you can reach by right-clicking the file or folder and clicking the Properties entry on the ensuing menu. In the Properties dialog, click the Security tab to get to an interface similar to that shown in Figure A.

Figure A

Security tab

From this interface, you can add users to the Permissions list, set specific permissions for each user or group, and grant special permissions via the Advanced button. Setting permissions and policies can seem a little daunting, but the basic principles are easy to understand: User A can access this folder and User B cannot. The numerous possible permission combinations should give you the flexibility to meet your security needs.

Visual Basic

Because OptionExplicit is using Visual Basic for his project, he will most likely have to add some code from the FileIOPermission class to check permissions for each user as he or she accesses the folder in question.

Solution 2

Another method for securing a folder or file involves encryption, which is also part of Windows XP Professional. Similar to permissions, the encryption configuration is reached by right-clicking the folder or file and then clicking the Advanced button on the ensuing Properties interface. The Advanced button brings you to a dialog similar to the one shown in Figure B.

Figure B


You can encrypt the file or folder by clicking the encryption check box. Keep in mind that no encryption scheme is completely crack-proof. Physical security—preventing access altogether—is really the most secure security.

Next Steps: Build your skills with these hand-picked resources
>Create and control shared folders in Windows XP
>MSKB - 290403: How to Set Security in Windows XP Professional That Is Installed in a Workgroup
>Microsoft TechNet: How to Share and Set Permissions for Folders and Files Using Windows XP
>Windows XP Professional Features

About Mark Kaelin

Mark W. Kaelin has been writing and editing stories about the IT industry, gadgets, finance, accounting, and tech-life for more than 25 years. Most recently, he has been a regular contributor to,, and TechRepublic.

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