Encryption is the process of converting data into a format that cannot be read by others. You can use EFS in Windows XP to automatically encrypt your data when it is stored on the hard disk.
Note:- The EFS feature is not included in Microsoft Windows XP Home Edition.You can encrypt files and folders only on volumes that use the NTFS file system.
Procedure to follow
1. Open windows explorer from Click Start, point to All Programs, point to Accessories, and then click Windows Explorer.
2. Locate and right-click the folder that you want, and then click Properties.On the General tab, click Advanced.
3. Under Compress or Encrypt attributes, select the Encrypt contents to secure data check box, and then click OK twice.
4. In the Confirm Attribute Changes dialog box that appears, use one of the following steps:
• If you want to encrypt only the folder, click Apply changes to this folder only, and then click OK.