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Why does Windows care whether a device driver is signed or unsigned? What is the difference?

Sometimes you see what might not be safe: unsigned drivers


Windows warning for unsigned drivers


When you download and start to install a device driver in Windows, you might see a warning that the driver is not signed and should not be installed.

What is a device driver? 

A device driver (also referred to as a driver) is a computer program that operates or controls a particular type of device that is attached to a computer.  It provides a software interface to hardware devices (such as our Total Phase products), which enables the operating systems, and other computer programs to access hardware functions without needing to know precise details about the hardware.

What is the difference between signed and unsigned drivers? Why does it matter?  

When a signed driver is digitally signed, it indicates this digital signature is associated with a digital certificate that identifies the “publisher” of the driver as verified by a independent certification authority. A correct digital signature also shows that the driver software is in its normal condition – it is not damaged, corrupted, manipulated, or otherwise changed from its original, normal condition. It is safe to use.

If the driver has been tampered with or changed in any way, then the signature becomes invalid and the driver is then unsigned. Unsigned drivers are considered potentially malicious. For the security and safety of your entire system,  Microsoft recommends only using signed drivers.  Windows will notify you if a driver is unsigned. Unsigned drivers do not have publisher verification or treaceability to a certification authority, and may have been changed since it was signed and released to the public.

How do I know if a driver that is already installed is signed or unsigned?

Unsigned drivers can cause problems such as system crashes and odd behavior. Check your system for unsigned drivers by using a File Signature Verification tool (such as sigverif.exe). The tool will display a list of any unsigned drivers you have installed on your computer. This is a good first step in troubleshooting driver-related problems. (Warning – please use caution before removing any video drivers – which are often unsigned. Removing a video monitor drive that is in use may disable your display and render it blank.)

What does this have to do with Total Phase?

  1. All Total Phase drivers are signed. We have gone through the additional certification steps to ensure that our customers’ computer is safe and protected from malware.
  2. Your security is important to us. One of the most popular ways to spread malware is through drivers. If a driver is signed, it means that it has been proven not to have any malware code. Our own internal policy promotes the use of signed drivers and we encourage our customers to do the same.
  3. Installing a signed driver is easier than installing an unsigned driver. Signed drivers will go through the standard Windows installation process. While unsigned drivers will result in error window pop-ups and delay the installation process.

We hope you found this information useful. If you have any questions about our Total Phase products, feel free to email us at sales@totalphase.com, or if you already own one of our devices and have a technical question, please submit a request for technical support.