I?ve got a driver that has a SHA1 signature using my cert, and a SHA256 signature using (a separate) EV cert, which was then cross-signed by the Microsoft Hardware labs using the attestation procedure. All signatures are timestamped within the past month or so.
This driver works well in testing so far. I?ve found it loads fine on Windows 8.1 64-bit, but won?t load on 8.0 64-bit with the dreaded ?Windows cannot verify the digital signature for this file.?
From everything I?ve read, 8 and 8.1 ought to be the same as far as driver signing goes, so I don?t understand this.
Interestingly, when I view the driver file properties, Digital Signature tab, in Windows Explorer, both show the correct signer name for the SHA1 signature. 8.1 shows the names for the SHA256, but 8.0 shows “Not available” for signer. But if you click into the certificate, Windows 8 shows the correct signer name. So something is different.
Also, 8.1 installed OK and the driver can be loaded. However, the compatibility (wizard?) popped up saying the driver installation was blocked (it wasn’t) because the driver isn’t signed (it is). I verified the driver is there and loads just fine with fltmc.exe
What a mess 
Does anyone have any ideas about why this might be failing for Windows 8?
Thanks for any input.
Doug