http://support.microsoft.com/kb/929395/ko Certification authority Web site Entrust http://www.entrust.net/microsoft/ (http://www.entrust.net/microsoft/) Comodo http://www.comodo.com/msexchange (http://www.comodo.com/msexchange) DigiCert http://www.digicert.com/unified-communications-ssl-tls.htm (http://www.digicert.com/unified-communications-ssl-tls.htm) GlobalSign http://www.globalsign.com/ssl/..