메모) cipher /w:[드라이브명] 해당 드라이브의 빈 공간을 덮어써 청소

알게 된 곳은 [ 링크 ] 입니다. 저렇게 동작하니까, 데이터 복구 프로그램이 손대지 못하게 하는 게 목적이겠죠.

WIPE 란 이름을 쓰는 유틸리티 종류와 비슷한데, 링크의 설명에서 보듯 cipher 는 파일과 폴더는 지우지 않는다고. 즉, 포맷이 아닙니다.

윈도 XP 이상에서 동작합니다. 윈도 내부 명령어란 점에서 알아둘 만 합니다.

아래는 이 명령어에 관한 MS 도움말을 전재한 것입니다.

출처:

http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/cipher.mspx?mfr=true

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Cipher

Displays or alters the encryption of folders and files on NTFS volumes. Used without parameters, cipher displays the encryption state of the current folder and any files it contains.

Syntax

cipher [{/e|/d}] [/s:dir] [/a] [/i] [/f] [/q] [/h] [/k] [/u[/n]] [PathName [...]] | [/r:PathNameWithoutExtension] | [/w:PathName]

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Parameters

/e : Encrypts the specified folders. Folders are marked so that files that are added to the folder later are encrypted too.

/d : Decrypts the specified folders. Folders are marked so that files that are added to the folder later are encrypted too.

/s: dir : Performs the selected operation in the specified folder and all subfolders.

/a : Performs the operation for files and directories.

/i : Continues performing the specified operation even after errors occur. By default, cipher stops when it encounters an error.

/f : Forces the encryption or decryption of all specified objects. By default, cipher skips files that have been encrypted or decrypted already.

/q : Reports only the most essential information.

/h : Displays files with hidden or system attributes. By default, these files are not encrypted or decrypted.

/k : Creates a new file encryption key for the user running cipher. If you use this option, cipher ignores all of the other options.

/u : Updates the user's file encryption key or recovery agent's key to the current ones in all of the encrypted files on local drives (that is, if the keys have been changed). This option only works with /n.

/n : Prevents keys from being updated. Use this option to find all of the encrypted files on the local drives. This option only works with /u.

PathName : Specifies a pattern, file, or folder.

/r:PathNameWithoutExtension : Generates a new recovery agent certificate and private key, and then writes them to files with the file name specified in PathNameWithoutExtension. If you use this option, cipher ignores all of the other options.

/w:PathName : Removes data on unused portions of a volume. PathName can indicate any directory on the desired volume. If you use this option, cipher ignores all of the other options.

/? : Displays help at the command prompt.

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Remarks

•	Using /w  /w removes data from portions of the volume it can access and have not been allocated to files or directories. It does not lock the drive, so other programs can obtain space on the drive, which cipher cannot erase. Because this option writes to a large portion of the hard volume, it might take a long time to complete and should only be used when necessary.
•	Encrypting or decrypting files To prevent an encrypted file from becoming decrypted when it is modified, it is recommended that you encrypt both the file and the folder in which it resides.
•	Using read-only files and folders Cipher cannot encrypt files that are marked as read-only.
•	Using multiple folder names You can use multiple folder names and wildcard characters.
•	Using multiple parameters You must separate multiple parameters by at least one space.

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Examples

To use cipher to encrypt a subfolder named May in a folder named MonthlyReports, type:

cipher /e monthlyreports\may

To encrypt the MonthlyReports folder, the January through December subfolders, and the Manufacturing subfolders within the month subfolders, type:

cipher /e /s:monthlyreports

To encrypt only the Marketing.xls file in the May subfolder, type:

cipher /e /a monthlyreports\may\marketing.xls

To encrypt the Marketing.xls file, the Maintenance.doc file, and the Manufacturing subfolder (located in the May folder), type:

cipher /e /a monthlyreports\may\ma*

To determine whether the May folder is encrypted, type:

cipher monthlyreports\may

To determine which files in the May folder are encrypted, type:

cipher monthlyreports\may\*