Encrypting File System (EFS) generates a self-signed certificate when you try to encrypt an EFS file on a Windows XP-based computer (912761)


The information in this article applies to:

  • Microsoft Windows XP Professional
  • Microsoft Windows XP Home Edition
Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry

SYMPTOMS

Consider the following scenario:
  • You try to encrypt an Encrypting File System (EFS) file on a Microsoft Windows XP-based computer.
  • No EFS certificate is available in the local certificate store.
  • No certification authority (CA) is available to issue an EFS certificate.
In this scenario, EFS generates a self-signed certificate. Then, EFS uses this self-signed certificate to encrypt the file.

RESOLUTION

Hotfix information

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Only apply it to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next Windows XP service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

To apply this hotfix, you must have Windows XP Service Pack 2 (SP2) installed on the computer.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix Replacement Information

This hotfix does not replace any other hotfixes.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.
File nameFile versionFile sizeDateTimePlatformSP requirementService branch
Cipher.exe5.1.2600.281956,32030-Dec-200501:03x86SP2SP2QFE
Lsasrv.dll5.1.2600.2819726,01630-Dec-200504:39x86SP2SP2QFE
Shell32.dll6.0.2900.28198,453,12030-Dec-200504:39x86SP2SP2QFE
Xpsp3res.dll5.1.2600.281922,52830-Dec-200500:56x86SP2SP2QFE

STATUS

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

MORE INFORMATION

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

After you install the hotfix, you can prevent EFS from generating self-signed certificates. To do this, follow these steps:
  1. Click Start, click Run, type regedit, and then click OK.
  2. Locate and then click the following registry subkey:

    HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows NT\CurrentVersion\EFS

  3. On the Edit menu, point to New, and then click DWORD Value.
  4. Type EfsOptions, and then press ENTER.
  5. Double-click EfsOptions, type 0 in the Value data box, and then click OK.
  6. Exit Registry Editor.
After you add the EfsOptions registry value, you must create a custom Administrative Template to define a new policy. This new policy will centrally manage the registry change. To do this, follow these steps:
  1. Start Notepad.
  2. Type the following text:
    CLASS MACHINE 
CATEGORY "System" 
CATEGORY "Public Key Policies"
POLICY "Encrypted File System" 
KEYNAME "Software\Policies\Microsoft\Windows NT\CurrentVersion\EFS"
PART "Allow EFS to Generate Selfsigned Certificate when a Certificate Authority is not available" CHECKBOX 
VALUENAME "EfsOptions"
VALUEON NUMERIC 4
VALUEOFF NUMERIC 0
END PART 
END POLICY 
END CATEGORY 
END CATEGORY
  3. On the File menu, click Save As.
  4. In the Save as typelist, click All Files.
  5. Type %windir%\inf\efscustom.adm in the File name box, and then click Save.

    Note The %windir% placeholder represents the drive letter of the Windows system folder.
  6. Exit Notepad.
  7. Restart the computer.


Note With you install this hotfix, you can still experience the old behavior if EfsOptions registry value is missing or is set to a value of 4. For more information about how to create custom Administrative Templates, click the following article number to view the article in the Microsoft Knowledge Base:

323639 How to create custom Administrative Templates in Windows 2000

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

Modification Type:MinorLast Reviewed:7/26/2006
Keywords:kbQFE kbHotfixServer kbWinXPsp3fix kbWinXPpreSP3fix kbfix kbbug kbpubtypekc KB912761 kbAudITPRO
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