This is the third post that concerns "keyboard filter". In the
previous post, after introducing the topic, we discussed how to
insert the "Keyboard Filter" package into the Windows Embedded
Standard 7 build, how to manage its service and how to configure it
in general. In this post we will go into more details on how to
"Configure and test predefined key combination" and "Configuring
custom filters"
Configure and test predefined key combination
Start the Local Group Policy Editor (gpedit.msc) with
administrator privileges and select the Keyboard Filter. Select the
shortcuts you want to block. In this example, we want to block the
following combinations: Ctrl+Alt+Del, Windows+R, and the Shift
key.
1. Verify that the key combinations mentioned above are working
properly.
a. Press Windows+R.
You should see the Run ... dialog box.
b. In the Run dialog box, press the key combination
Shift+A.
You should see a capital letter.
c. Finally, press Ctrl+Alt+Del.
You should see the screen with options to lock the computer,
change users, etc.
d. Press the Esc key to return to your desktop and close the
Run dialog box.
2. The predefined key combinations are grouped into categories.
Inside the Security Keys folder, you will find the
Block Secure Desktop (Ctrl+Alt+Del) setting.
a. To enable this lock combination, double-click on
settings.
b. Select the Enabled option in the top left of
the dialog box, and press OK.
Note: The Enabled option blocks the key
combination. This enables the filter, not allowing the keys
combination.
c. In the left pane, select Keyboard Filter.
d. Select Desktop and Shell Keys.
e. Select Block Run Dialog (Windows + R).
f. Double-click, select Enabled and press OK.
g. In the left pane, select Keyboard Filter
again.
h. Select Modifier Keys.
i. Double-click on Block Shift Keys.
j. Select Enabled and press
OK.
k. Wait at least five seconds from the moment you press the
Apply button or OK.
The Local Group Policy Editor (gpedit.msc) may require more time
to save the settings, especially on slower hardware or on systems
in domains.
Note: An event is logged in Windows Event
Viewer when the filter keyboard loads the new settings and becomes
active.
l. Check the key combinations that you just configured.
If everything worked, should be disabled: Ctrl+Alt+Del would not
bring up the screen with options to lock the computer, change
users, and so on ...; Windows+R should not bring up the Run dialog
box .... Any keys combination with the Shift key would not work,
and the capital letter is a good example to prove that this does
not work.
Nota: Keyboard filtering is disabled on the
secure desktop. Try logging off the system. You can then enter
Shift+A for an uppercase A in the password field. Disabling
keyboard filtering guarantees that that users and administrators
can successfully log on to the computer.
Configure custom key combinations
The part of custom key combination filters allows you to create
shortcuts NOT included in the predefined group.
To encode the filters must be adhered to a number of rules and
limitations, but let's start with a couple of definitions that will
serve us later:
- By "modifier keys", we mean those that are used in combination
with other keys: Ctrl, Alt, Shift and Windows. you can also specify
if they are left or right: LCtrl, RCtrl, LAlt, RAlt, LShift,
RShift, LWindows and RWindows.
- Filters should be expressed with a combination that contains
zero or more modifier keys and a character, number, function or
cursor key, delimited by a plus symbol.
Here are some notes which follow:
· The modifier keys cannot be given alone (for this you can use
the predefined filters);
· To create filters for a capital letter, select
Shift+<letter>. For example, if you filter the Z key, you
lock only lowercase z. To filter the capital Zyou
need to filter forShift+Z.
· To filter a number, you must also filter the same key in the
numeric-pad. For example, if you want to block the 8 key, you must
also filter the Up key. This way you cannot filter the number 5 of
the numeric pad.
· If you filter the numeric keypad keys (Up, Down, Left, Right,
Home, End, Page Up, Page Down), the keys will be locked for the
corresponding numbers. The line numbers above the letters will
continue to operate normally.
· You can filter the function keys F1 through F24 keys and
CapsLock, PrintScrn, ScrollLock, Break, Tab, Space, Backspace and
Esc. Remember to do not put spaces in the names, but they can be
written both uppercase and lowercase.
· You can filter the keys: Up, Down, Left and Right (arrows
moving); PageUp, PageDown, Insert, Delete, Home and End. Do not put
spaces in the names that can be written in both uppercase and
lowercase.
· When you create a filter for the navigation arrows: Up, Down,
Left, Right, and so on is also good to remember to filter the
combinations with the Shift key to ensuring that a combination
Shift+Up (for example) obstruct the filter on Up .
Here are examples of custom filters:
· Windows+L
· LWindows+L
· Ctrl+Break
· Shift+Ctrl+Esc
· Ctrl+C
· Ctrl+Enter
_______________________________
In the next post of this article, we will deal with how
"Configure Keyboard Filters for Non English Keyboards" and "Filters
keyboard and screen keyboard".
These articles, divided into post, were written, revised and
translated into English as well as by me by other two colleagues of
mine (both Microsoft Certified Trainer for Windows Embedded
Standard 7): Gianni Rosa Gallina and Dorangela Daniele.
