@miniwahib1

I found a very good article about how to implement I/O trapping using pentium debug registers.
hxxp://bugtraq.ru/library/programming/haspprotection.html
Maybe it should be useful if you want to write a VXD replacement for WKPE.

There are already other progs who can use the same i/o trap method, like the Virtual DOG emulator (still Win9x only), or the Safekey's "delaynt" driver (NT/2000/XP).

In case you aren't too much familiar with pentium control & debug registers, maybe this slide should helps:
hxxp://www.cs.usfca.edu/~cruse/cs635/lesson10.ppt