Is codesigning supposed to work from non-windows?

When I try to build the app from a non-windows machine (Ubuntu 15.10 in this case), I get the following error:

```
Error: Failed with exit code: 255
Output:
System.AggregateException: One or more errors occurred. ---> System.Exception: Failed to sign, command invoked was: '[path censored]/node_modules/electron-winstaller/vendor/signtool.exe sign /a /f "/[path censored]/build/codesigningcertificate.pfx" /p "[password censored]" [path truncated]/.local/share/SquirrelTemp/tempa/lib/net45/[filename censored].exe'
```

There's also a long stacktrace not included for the sake of brevity.