There is a mistake in the previous message. Of course I meant: "I'm NOW convinced that there is NO solution for this problem." SPEED KILLS :eek:

Ok guys I did some research on hooks and I'm know convinced that there is know solution for this problem. The only thing to do, in my opinion, is to warn the user and give him the responsibility to keep his computer free of viruses and stuff like that. Thanks anyway. X|

The text is already secured through a hash value, so it can't be corrupted. But this other program is able to write into my window and the user sees something different than he signs! This other thing, with the virus looking like my ActiveX is a problem too. I thought I can do something in correspondence with the server programm to which the signed file is sended. Do you have any ideas? Martin

I'm writing a high security digital signature ActiveX control. And I thought it would be bad if another program writes into my window and then the signer thinks he signs something different then he really signs. I try know with Win32 Hooks. I hope this helps.

Hi As far as I know it is possible for other applications to get a handle of the window from my application (e.g.: FindWindow), and then it is possible for this application to write into my window. Does anyone know a method to prevent this? Thanks in advance :confused: