This step-by-step article describes how to encrypt offline files to secure data in Windows XP.
You can mark any shared folder that is available on the network or any Web page to be made available offline. The contents of these shared folders or pages are copied to a folder on the hard disk on your local computer. For added security, you can specify that the offline files that are stored locally be encrypted.
Offline files are stored on the local computer in an Offline Files database that is known as the client-side cache. In Windows XP Professional, you can specify that the client-side cache is encrypted to safeguard offline files against theft. When encryption of offline files is enabled or disabled, the entire database is affected; you cannot encrypt only some offline files.
To encrypt the Offline Files database on a local computer:
Click Start, and then click Control Panel.
If Control Panel is in Classic view, double-click Folder Options. If Control Panel is in Category view, click the Appearance and Themes link, and then click Folder Options.
Click the Offline Files tab.
If Offline Files are not already enabled, click the Enable Offline Files option.
NOTE: If you are using the Fast User Switching feature in Windows XP, you will not be able to use offline files, and none of the options on the Offline Files tab will be available. To disable Fast User Switching, use the User Accounts utility in Control Panel.For more information about fast user switching in Windows XP, click the following article number to view the article in the Microsoft Knowledge Base:
279765 HOW TO: Use the Fast User Switching Feature
Click the Encrypt offline files to secure data option.
Windows XP will now automatically encrypt offline files as they are stored in the local Offline Files database.
WARNING: Some programs, such as Microsoft Word, create temporary copies of open files in other folders, such as the TEMP folder. For this reason, you might want to encrypt any other folders that are used by your programs.