I would like to make it possible for university workers to sign their infopath forms digitally outside of IE. Is there a way to do this or should I just look at including an install of the InfoPath filler with every staff machine?
According to this link, http://technet.microsoft.com/en-us/library/cc263526.aspx, InfoPath Form Signing uses an ActiveX control.
I don't believe any browser supports ActiveX other than IE: http://support.mozilla.org/en-US/kb/ActiveX https://tools.google.com/chrome/intl/en/webmasters-faq.html#activex
Needless to say, there are other pieces of functionality in SharePoint that rely on ActiveX that will not work for you either. This is why FireFox is listed with "limited support". I think Chrome obtained the "Supported with limited support" status, officially, with SharePoint 2010 SP1.
Yes, you can use The CoSign Connector for SharePoint. It integrates with SharePoint and enables server-side digital signing of InfoPath forms and standard doc types such as .doc, .docx, .xls, etc from the SharePoint web user interface (using any browser).
Disclosure: I work for CoSign.