Windows XP in a Nutshell, Second Edition

Name

NTFS Encryption Utility — \windows\system32\cipher.exe

Synopsis

View or configure the automatic file encryption on NTFS drives. (NTFS Encryption Utility is included with Windows XP Professional only.)

To Open

Command Prompt → cipher

Usage

cipher [/e|/d] [/s] [/a] [/i] [/f] [/q] [/h] [filename]

cipher /k

cipher /r:efs_file

cipher /w:dir

cipher /u [/n]

Description

Encryption is used to prevent unauthorized access to your data, and one of the features of the NTFS filesystem (see “FAT to NTFS Conversion Utility”, earlier in this chapter) is its built-in support for automatic encryption of files and folders using “public key cryptography.” NTFS encryption is invisible and encrypted files are opened as easily as decrypted files. The difference is that other users, either those who access your computer remotely (via My Network Places, Telnet, or FTP) or those who also log into your computer under a different user account, will not be able to open or read encrypted files on your system.

Right-click on any file or folder, select Properties, and then click the Advanced button. The “Encrypt contents to secure data” option is used to instruct Windows to encrypt the selected item. If a folder is selected, all of its contents will be encrypted (you’ll be prompted about any subfolders); furthermore, any files added to that folder will be automatically encrypted as well.

The NTFS Encryption Utility is the command-line equivalent of this setting, but it adds several powerful features not normally ...