com.apple.WebKit.Networking.xpc wants to sign using key "privateKey" in your keychain.

I've seen this error in a few other areas of the forums; however, I'm trying to understand what does "key 'privateKey'" means. I'm trying to authenticate to a VPN portal and this is the error that pops up when I browse to the site. I was provided a .pfx file, imported it into my "login" keychain, and now I'm trying to use it when browsing to this site.

Perhaps my understanding of all of this is horrible, but I thought I'd at least post about it and see if anyone could provide any valuable feedback.

Thanks,