How do make sure only legitimate people an get into Conference using SX20

Question

  Customer Scenario-( I) :Customer has SX20 registered with CUCM9.x, there is no TP Server and no TMS for Scheduled conference.
 I understand the concept of secure conferencing but this would be between the Endpoint and the Server-UC Application:
Secure conferencing is a way to use regular conferencing to ensure that the media for the conference is secure and cannot be compromised. There are various security levels that a conference can have, such as authenticated or encrypted.
With secure conferencing, the devices and conferencing resources can be authenticated to be trusted devices, and the conference media can then be encrypted so that every authenticated participant sends and receives encrypted media for that conference.
However, like to understand if it possible at User Level as well by prompting the user to enter login credentials for getting into the conf call.
Please Note, its not a scheduled conf call scenario. Its a typical Rendezvous conf example:
  Query1: Is there some provision where in if some one dials into SX20 from internet (outside corporate network), to ensure only legitimate people can get into MultiSite conference (3+1), calling party (who dials into SX20) needs to enter credentials (UserName & Password) for Authentication?
 Query2: If Query 1 is not possible using Rendezvous conf, then is it possible using Schedule conference with TP server and TMS or just by using TP Server ?
Thanks & Regards
Sumit Bhargava

Answer 1

If someone is dialling in to your SX20, then you have the option to answer the call or not (assuming you don't have it set to auto-answer) - it's then up to your user to accept someone in to, or reject someone from, their conference.