According to the Nutanix Prism Element Guide, Prism Element uses a single SSL certificate on a Nutanix cluster. The certificate is used to secure the communication between the web browser and the Prism web console. The certificate is also used to authenticate the cluster to external services, such as Active Directory, SMTP, and SNMP. The certificate can be either self-signed or signed by a trusted certificate authority (CA). The certificate can be replaced or renewed through the Prism web console or the ncli command-line interface.