You can use quickStartSecurity element or any supported user registries for the administrator role mapping on the Liberty profile.
All the JMX methods and MBeans accessed through the REST connector are currently protected by a single role named "administrator". To get started quickly, use quickStartSecurity element to configure a single user with administrator role and configure the default SSL configuration.
You can also use any supported user registry. You cannot use quickStartSecurity element if you have already configured another user registry. In this case, you have to map users or roles from the registry to the administrator role.