An X.509 certificate used for StandaloneClientCertificateRequestedEventArgs.
StandaloneX509CertificatePrincipal Subject The subject of the X.509 certificate. For HTTPS server certificates this represents the web server. The common name of the subject should match the host name of the web server.
DateTime ValidExpiry The DateTime after which the X.509 certificate is invalid, or DateTime.MinValue if no date was specified.
DateTime ValidStart The DateTime before which the X.509 certificate is invalid, or DateTime.MinValue if no date was specified.