I have used QSslServer and passed the

QSslCongifuration::defaultSslConfiguration()

value to use it as the configuration data. Seems pretty easy in that respect.

The default SSL configuration consists of: no local certificate and no private key protocol SecureProtocols the system's default CA certificate list the cipher list equal to the list of the SSL libraries' supported SSL ciphers that are 128 bits or more

Another option is

QSslConfiguration::defaultDtlsConfiguration()

You have full control over certs, keys, etc. in the QSslConfiguration object. Just depends on how detailed you need to get with it. Usually in my case it's a "same host" sort of deal so I just use the default config.