Did you just find a file that has a digital signature from GRISOFT LTD? If that's the case, please read on.
You'll probably notice GRISOFT LTD when clicking to run the file. The publisher name shows up as the "Verified publisher" in the UAC dialog as the screenshot shows:

You can also view the GRISOFT LTD certificate with the following steps:
Here's a screenshot of a file that has been digitally signed by GRISOFT LTD:

As you can see in the screenshot above, Windows reports that "This digital signature is OK". This implies that the file has been published by GRISOFT LTD and that no one has tampered with the file.
If you click the View Certificate button shown in the screenshot above, you can view all the details of the certificate, such as when it was issued, who issued the certificate, how long it is valid, and so on. You can also view the address for GRISOFT LTD, such as the street name, city and country.
VeriSign Class 3 Code Signing 2004 CA has issued the GRISOFT LTD certificates. You can also view the details of the issuer by clicking the View Certificate button shown in the screenshot above.
These are the GRISOFT LTD files I've collected, thanks to the FreeFixer users.
| Detection Ratio | File Name |
|---|---|
| 0/43 | avgascln.sys |
| 0/47 | avgarkt-setup-1.1.0.42.exe |
| 0/68 | avgasc64.sys |
The detection percentage is based on that I've gathered 158 scan reports for the GRISOFT LTD files. 0 of these scan results came up with some sort of detection. If you like, you can review the full details of the scan results by examining the files listed above.
The analysis has been done on certificates with the following serial numbers: