Rob MacFadyen writes:

Ok.. so to automate signcode such that is does not prompt for a password the steps are as follows:

1. Get the keyimprt.exe tool
   http://msdn.microsoft.com/vba/technical/pvk.asp
   Note: This is a self extracting exe that expands into another self extracting exe (named the same), that then extracts to an installer. The installer then installs 2 files (again the .exe name is the same)
2. Import your .SPC and .PVK using the tool and instructions from #1. This will ask for your password. Pick the store explicitly, and pick the "Personal" store.
3. Use the "certmgr.exe" tool to view your new key and determine what it's common name (cn) is. You can start certmgr.exe from IE by Tools->Internet Options, then on the "Content" tab click the "Certificates..." button
4. Use signcode.exe as follows (line breaks add for clarity):
   signcode.exe
  -s my
  -cn "Your Cert CN"
  -t http://timestamp.verisign.com/scripts/timstamp.dll
  "YourFileToSign"
   
   Note: If you specify the "YourFileToSign" incorrectly you get a cryptic message: "One or more input parameters are invalid." instead of a more useful "file not found" message (there's 2 hours I'll never get back).

That's it... you may also want to include the "-info" switch to add a url that is displayed to the user as "more info".