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Problem

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

Encryption

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.

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<a target=Create and control shared folders in Windows XP
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<a target=MSKB – 290403: How to Set Security in Windows XP Professional That Is Installed in a Workgroup
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<a target=Microsoft TechNet: How to Share and Set Permissions for Folders and Files Using Windows XP
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<a target=Windows XP Professional Features