Securing NRDP communication.
It’s very important to secure NRDP based communication in Nagios for this SSL/TLS based encryption certificate that can be used.
The same certificate can be used for the Nagios server as NRDP runs on the same Nagios server.
For documentation of how to configure SSL/TLS certificate
https://support.nagios.com/kb/article/nagios-core-configuring-ssl-tls.html
Also, enable https based params inside /usr/local/nrdp/server/config.inc.php
$cfg[“require_https”] = true;
This will ensure that only https URL is used/browsed instead of non-secure HTTP.