Thanks for the suggestion grey! I just uploaded a new version (1.20 of BlitzKey). The new version of BlitzKey does a CRC check on the DLL before a DLL function is called (it will halt the application with a runtime error if invalid). Also, secret key codes are encrypted like Grey Alien suggested.
The new version is availible at the same location as the original file (HERE)
The new version is availible at the same location as the original file (HERE)