The cipher.exe command is an external command that is available in Windows 200, XP, Vista, and 7, and displays or alters the encryption of directories [files] on NTFS partitions. The above lists are syntax switches that allow you encrypt decrypt, or even manage file/folder encryption.
/E Encrypts the specified directories. Directories will be marked so that files added afterward will be encrypted.
/D Decrypts the specified directories. Directories will be marked so that files added afterward will not be encrypted.
/S Performs the specified operation on directories in the given directory and all subdirectories.
/A Operation for files as well as directories. The encrypted file could become decrypted when it is modified if the parent directory is not encrypted. It is recommended that you encrypt the file and the parent directory.
/I Continues performing the specified operation even after errors have occurred. By default, CIPHER stops when an error is encountered.
/F Forces the encryption operation on all specified objects, even those that are already encrypted. Already-encrypted objects are skipped by default.
/Q Reports only the most essential information.
/H Displays files with the hidden or system attributes. These files are omitted by default.
/K Create new file encryption key for the user running CIPHER. If this option is chosen, all the other options will be ignored.
/W Removes data from available unused disk space on the entire volume. If this option is chosen, all other options are ignored.
/X Backup EFS certificate and keys into file filename. If efs file is provided, the current user’s certificate(s) used to encrypt the file will be backed up.