To comply with the kernel-mode code signing policy of 64-bit versions of Windows Vista and later versions of Windows, you must obtain a WHQL release signature or use a Software Publisher Certificate (SPC) to sign the catalog file of kernel-mode driver packages.
If the driver is a boot-start driver for 64-bit systems, you must also embed an SPC signature in the driver file. This applies to any type of Plug and Play (PnP) or non-PnP kernel-mode driver.
The Hardware Certification Kit (HCK) has test categories for a variety of device types. To comply with the PnP device installation requirements of 32-bit versions of Windows Vista and later versions of Windows, you should obtain a WHQL release signature if the HCK has a test category for the device type. If you cannot obtain a WHQL release signature, you must use either an SPC or a commercial release certificate to sign a PnP kernel-mode driver.