verifying Deluge's installer for Windows

[GoudaEater]

Greetings.

I hope that someone might address the following philosophical concern that I have about installing Deluge on Windows.

I have noticed that my web browser (Firefox) gives me the following security warning when I try to connect to https://deluge-torrent.org:

This certificate is valid only for the following domains:
*.osuosl.org , osuosl.org
The certificate expired on 2009-08-19 02:48. The current date is 2013-05-18 12:48.

Therefore is it not theoretically possible for me to be the object of some sort of data-interception and data-substitution attack that would render malicious the installer that I have downloaded from this website? How might I verify the authenticity of the installer?

I am aware that I have omitted certain technical details and consideration for the sake of brevity. I am also aware that the type of attack to which I refer requires much technical sophistication. I make my enquiry out of interest rather than fear.

[Cas]

File hashes are in the release notes http://dev.deluge-torrent.org/wiki/ReleaseNotes/1.3.6