in XP system For those who have used Windows, almost no one does not know Ctrl+Alt+Del combination key, especially when using Windows9x which often crashes, it is used more frequently. The key combination is an emergency exit specifically for system security. In the 11th issue of VC Knowledge Library Online Magazine, ac952_z_cn wrote an article about this in his personal column: “How to block CTRL+ALT+DEL” under WINDOWS NT/2000. Therefore, this article focuses on how to implement the shield CTRL+ALT+DEL key combination in Windows XP, namely Task Manager, Task Switch Combination Key (Alt+Tab), Taskbar and “Start”Menu (Ctrl+Esc, VK_LWIN, VK_RWIN). This method can also be applied to Windows 2000 environments.
In the Windows 9x/Me system, the method of masking Ctrl+Alt+Del and various task opening keys is implemented by the following method:
BOOL bOldState;
SystemParametersInfo(SPI_SETSCREENSAVERRUNNING, TRUE, & bOldState, 0);
MS Dawei thinks this method is very amateur, so this has been modified in Windows NT/2000/XP. In these newer versions of Windows, users log in using Winlogon and GINA——Graphical Identification and Authentication, which means graphical identity authentication, which is quite scary! In fact, it is the case. Winlogon is part of the Windows system, which provides interactive login support, while GINA is a DLL&mdash used by Winlogon to implement authentication. This DLL is msgina.dll. WlxInitialize, WlxActivateUserShell is the output, of course, I do not know these two, there are others. The former performs its own initialization, which activates the user's shell. Windows uses this DLL to implement username + password authentication, but developers can use their own GINA instead of msgina.dll. For example, an authentication mechanism such as a smart card, a retina scanner, a DNA check, or the like is implemented instead of an identity check in the form of a username + password. All the functions related to GINA are listed in the table below. One of them is WlxLoggedOnSAS, which is called by Winlogon when the Ctrl+Alt+Del key is pressed.
(Table 1) GINA function list function description
WlxActivateUserShell activate user shell
WlxDisplayLockedNotice allows GINA DLL to display lock information
WlxDisplaySASNotice Winlogon calls this function when no user logs in
WlxDisplayStatusMessageWinlogon Status information is called to display this function
WlxGetConsoleSwitchCredentials Winlogon calls this function to read the trust information of the currently logged in users and transparently pass them to the target session
WlxGetStatusMessage Winlogon Call this function to get the current status information
WlxInitialize The specified window position for GINA DLL initialization
WlxIsLockOk Verify workstation normal lock
WlxIslogoffOk Verify logout normal
WlxLoggedOnSAS User has logged in and the workstation is not locked. If SAS event is received at this time, Winlogon calls this function
WlxLoggedOutSAS No user login, if SAS event is received at this time, Winlogon calls this function
WlxLogoff informs GINA DLL when requesting logout operation
WlxNegotiate Indicates whether the current Winlogon version can Using GINA DLL
WlxNetworkProviderLoad After loading the network service provider to collect identity and authentication information, Winlogon calls this function
WlxRemoveStatusMessage Winlogon Call this function to tell GINA DLL to stop displaying status information
WlxScreensaverNotify Allow GINA and screen saver operation Interaction
WlxShutdown This function is called by Winlogon before closing, allowing GINA to implement any shutdown tasks, such as exiting the smart card from the reader.
WlxStartApplication Call this function when the system needs to launch the application in the context of the user
WlxWkstaLockedSAS When the workstation is locked, if a SAS is received, Winlogon calls this function
By default, GINA displays the login dialog, and the user enters the username and password. So if you want to mask Ctrl+Alt+Del, you can write a new MyGina.dll, which provides the function WlxLoggedOnSAS that calls msgina.dll to implement Ctrl+Alt+Del masking. Or write a keyboard driver to implement.