1. A computer-readable storage medium comprising computer-executable instructions that, when executed by a computing device, cause the computing device at least to: establish a data session with an authentication server for authenticating a user to utilize a service; send a device ID over the data session to the authentication server; receive a sample phrase over the data session; present a voiceprint matching prompt on a display of the computing device, the voiceprint matching prompt comprising a request for the user to speak the sample phrase; receive a speech input of the sample phrase; and transmit the speech input to the authentication server via the data session.