Windows XP Hacks

Hiding Folders and Files with the Encrypting File System

Protect all the information on your PC from prying eyes, using XP Professional’s built-in encryption scheme.

If you have Windows XP Pro, you can use the Encrypting File System (EFS) to encrypt your files so that no one else can read them.

Tip

Home Edition users won’t be pleased to know that EFS isn’t available for Windows XP home users.

EFS lets you encrypt only the files and folders of your choice; you can encrypt a single file or folder, or all of your files and folders. Encrypted files and folders show up in Windows Explorer as green, so you can tell at a glance which have been encrypted. You can work with encrypted files and folders transparently. In other words, after you encrypt them, you open them and close them as you normally would any other file. They’re decrypted on the fly as you open them, and then decrypted as you close them. You’re the only person who can read or use the files. Encryption is tied to your account name, so even other accounts on the same computer won’t be able to read or use them, unless you specifically grant access to certain accounts.

Tip

Each time you encrypt a file, EFS generates a random number for that file called the file encryption key (FEK). EFS uses that FEK to encrypt the file’s contents with variant of the Data Encryption Standard (DES) algorithm, called DESX. (DESX features more powerful encryption than DES.) The FEK itself is encrypted as well, using RSA public key-based encryption. ...