Is there any way I can repurpose existing ActiveX controls or functionality to get IE to work with the KeyGen element?
Assistance getting Safari to work with this optional HTML5 spec would be appreciated as well.
The simple answer is 'No'. http://lists.w3.org/Archives/Public/public-html/2009Sep/0043.html has a Microsoft engineer basically explaining why ("The problem with is that it fails to address the requirements that people have for certificate enrolment today").
Of course, all of these are dated 2009, but I couldn't find any evidence Microsoft had changed their thinking.
Safari also appears to have native support (http://developer.apple.com/library/safari/documentation/AppleApplications/Reference/SafariHTMLRef/Articles/HTMLTags.html#//apple_ref/doc/uid/30001262-keygen).