what are digitally signed drivers

after the difficulty experience with the windows 2000 Microsoft has realized the importance of driver compatibility with windows.the hardware manufactured and then come up with there driver compatible with Microsoft operating systems.and they were tested at Microsoft labs.once a driver found compatible with Microsoft it was added with the CAB file as a digital signature.now when drivers installing into windows its looks for this CAB file.the drivers are proceeded if it founds digital signed,but otherwise there are 3 option of actions as below.

• ignore
• warn
• block