You can get security settings of a content item with the getContentItemPermissions method.
|credentials (required)||credentials||Read the description of the Credentials object.|
|contentItemId (required)||string||ID of a content item, which security settings you want to get.|
After the request has been completed, the system returns an object with the following properties:
|privacy||string||Content item type (public or private)|
|isViewedOnce||bool||True, if a given content item can be viewed only once.|
|users||string||An array of user IDs, who have permissions to view a given private content item.|
|groups||string||An array of group IDs, which members have permissions to view a given private content item.|