Techniques are provided that validate a participant in a video conference. As a video conferencing system is remote from a video conference participant, and user devices are not trusted, traditional methods such as client side facial recognition are ineffective at validating a participant from a video conferencing system. Thus, the embodiments encode modulated data for projection onto a face of the participant. A video of the participant is then captured. The conferencing system then confirms that the modulated data is present in the captured video.