The Encrypted File System (EFS) is part of the Windows XP Professional OS, it allows users to easily encrypt/decrypt their data files. The way EFS works is Windows automatically creates the keys needed to encrypt and decrypt the files. Then when a file is requested by an application Windows uses the keys to decrypt the file, and when the file is saved it automatically re-encrypts it.
Use the steps below to enable file encryption:
- Open My Computer, and find the file or folder you want to encrypt.
- Right-click the file or folder, and select Properties.
- In General tab, press the Advanced button.
- Check the 'Encrypt contents to secure data' checkbox.
- Press OK buttons to dialog boxes.
Note: You can not use both NTFS compression and encryption on the same file. If compression is enabled, it will automatically disable the encryption feature.