Coding a touchscreen password program can ctrl-alt-del be disabled?

**alti** · 06-26-2005, 05:07 AM

Question for all the coding monkeys and non monkeys.

I am trying to code a touch screen password program in VB.net that is basically a rip off of StevieG's audio recording password software, accept I did not really need the recording feature, and I wanted to code so it gave me a reason to.

I have the program working great with one problem, I have been searching for a way to stop the users ability to get around the applications having focus by killing it in task manager. With just a touch screen interface this is not a problem I have the window set to no border, maximized and topmost. but as soon as a smart or curious person finds my computer in the trunk and plugs in a keyboard they will eventually try alt-crtl-del and end the task/process.

From my googleing attempts the only info I have garnered is that is not possible to with code in XP, is this true? The only way to do it is by replacing the GINA.dll file with a modified version disabling the task manager or modifying the users permissions to not allow the user to do it. Neither of these solutions work for me as after my app closing I still want it to be business as usual.

Any ideas?

here is a screen shot of the app. (the picture of my stock radio where the radio is supposed to be is ment to deter would-be thieves

)

**god_of_cpu** · 06-26-2005, 10:51 AM

No, you can't do it easily with code. The typical way to block keys is with a global keyboard hook, however, these are processed after ctrl+alt+del. The only reliable way I found is to hack the registry and remap the keys.

http://www.northcode.com/resources/kiosk/kiosk.html

**CdRsKuLL** · 06-26-2005, 11:37 AM

the way I would look at it.. if you got a touch screen, then chances are your keyboard would be hidden anyway.. and how many people would think about pressing these keys anyway ?

CdR

**Gobby** · 06-26-2005, 11:44 AM

Good point Cdr .... I disconnect my USB Keyboard when not in use and put in the back under my seat.

**tj!2k4** · 06-26-2005, 12:07 PM

Originally Posted by god_of_cpu

No, you can't do it easily with code. The typical way to block keys is with a global keyboard hook, however, these are processed after ctrl+alt+del. The only reliable way I found is to hack the registry and remap the keys.

http://www.northcode.com/resources/kiosk/kiosk.html

keep in mind that i know nothing about programming, but here is my $0.02:

this similar to what I was thinking, except you might just want to intercept ctrl and alt keys.. then alt-tab, ctrl-alt-del, and ctrl-shift-esc won't work.

**justintime** · 06-26-2005, 12:19 PM

I think that is a good idea too.. can't you look out for crt-alt key combo, and as soon as they are pressed you display a msgbox("no you don't!") ?

Originally Posted by tj!2k4

keep in mind that i know nothing about programming, but here is my $0.02:

this similar to what I was thinking, except you might just want to intercept ctrl and alt keys.. then alt-tab, ctrl-alt-del, and ctrl-shift-esc won't work.

**alti** · 06-26-2005, 02:13 PM

Thanks for all of the replies guys!

The way I understand it the crtrl and alt keys are processed olny when another key (such as del) is pressed. The computer looks to see if the ctrl or alt where down @ at the time the keypress of del happend. So like God_of_Cpu and CDrSkull said the above wont work

I did find way to do it in 9x windows appearently it was quite easy to there.

I had hoped there was a "known loophole", but had a feeling there wasnt.

Thanks again guys.

**Peoples** · 06-26-2005, 02:17 PM

um, i havent done it in a while, but i recall there is a way to register your app with windows as a screen saver, then when the task manager does pop up, your program is not listed...cant remember the code though.....this might not work in XP.....that mighta been in the days of 98

**alti** · 06-26-2005, 02:22 PM

Originally Posted by Peoples

um, i havent done it in a while, but i recall there is a way to register your app with windows as a screen saver, then when the task manager does pop up, your program is not listed...cant remember the code though.....this might not work in XP.....that mighta been in the days of 98

that is exactly the way to do it for win 9x, unfortunitaly they ended it for win 2000/xp