The signature score ranks a driver according to how the driver is signed, as follows:
Windows assigns the best signature score (lowest signature score value) to drivers that have a signature from a Windows signing authority. This includes the following:
Windows assigns the second best signature score to a driver that was signed by a third-party using Authenticode technology or a driver that has a WHQL signature for a Windows version that is earlier than the version that is specified by the LowerLogoVersion value that is set for the device setup class of the driver.
Valid third-party signature types include the following:
- Drivers signed by using a code signing certificate from an Enterprise Certificate Authority (CA).
- Drivers signed by using a code signing certificate issued by a Class 3 CA.
- Drivers signed by using a code signing certificate created by the MakeCert Tool.
For more information about the .nt extension, see Creating INF Files for Multiple Platforms and Operating Systems.
Windows assigns the fourth best signature score to driver packages that do not have a valid signature, and the driver is not installed by an INF DDInstall section that has an .nt platform extension.
Windows assigns the fifth and worst signature score (highest signature score value) to drivers that are not signed or whose signing state is unknown.
For more information about driver ranking, see How Windows Ranks Drivers.