1. A method comprising: receiving a request from a speaker to confirm a user identity; retrieving a user profile associated with the user identity; generating, based on the user profile and a level of security desired, a text challenge, wherein generating the text challenge is based on eliciting distinctive behavior of the speaker when compared to behavior of other users, the behavior of other users and the highly distinctive behavior of the speaker being stored in a database of dynamic image features; prompting the speaker to utter the text challenge; recording an audio recording and a video recording of the speaker as the speaker utters the text challenge; and performing speaker verification using the audio recording, the video recording, and the user profile.