Two Way TLS is a mandatory requirement for server based application to integrate with SEI APIs. To facilitate Two Way TLS an identity certificate with CN matching the service account username is needed. During the Application registration process if the client selects SEI Cert that would mean that SEI will provision the certificate using trusted parties such as Trustwave or Entrust and provide it to the client. The SEI cert download link and instructions i valid until one download. Once the Cert has been downloaded the download link will not work again. If the cert has not been downloaded and the link expires , please contact SEI and we can issue a new link. The SEI cert will expire after 2 years. The client will be notified ahead of the expiration time about requesting a new cert to avoid production issues.