One disclosed example method includes obtaining a meeting cryptographic key, transmitting, from a client device to a video conference provider, a request to initiate an encrypted video conference, the encrypted video conference including a plurality of participants, and distributing the meeting cryptographic key to each participant of the plurality of participants. The disclosed example method further includes receiving an indication that the encrypted video conference is to be locked, subsequent to receiving the indication that the encrypted conference is to be locked, receiving a request to admit an additional participant to the encrypted video conference, determining whether the additional participant is one of the plurality of participants, and responsive to determining that the additional participant is not one of the plurality of participants, rejecting the request to admit the additional participant to the encrypted video conference.