On a Windows XP machine digital certificates have been imported into the certificate store using the Certificate Import Wizard. And verified using IE7 to login into an internal site. In FireFox, when I choose "Digital Certificate" as a login option I get the following message: The page requires a client certificate The page you are attempting to access requires your browser to have a Secure Sockets Layer (SSL) client certificate that the Web server will recognize. The client certificate is used for identifying you as a valid user of the resource.