1. A non-transitory computer-readable storage medium comprising computer-executable instructions that, when executed by a computing device, cause the computing device to perform operations comprising: establishing a data session with an authentication server; receiving a sample phrase over the data session, the sample phrase comprising a challenge phrase comprising a rewording of a challenge question as a statement comprising a blank portion for an answer to the challenge question; presenting a voiceprint matching interface on a display of the computing device, the voiceprint matching interface comprising: text corresponding to the statement, a request for the user to speak the statement and to speak the answer to the challenge question in the blank portion of the statement, a first option that, when selected by the user, plays audio corresponding to the statement, and a second option that, when selected by the user, initiates a recording via a microphone of the computing device to record the statement spoken by the user; receiving a speech input in response to the request; inserting a device-specific audio artifact in the speech input of the statement spoken by the user, the device-specific audio artifact being inserted in the speech input of the statement spoken by the user in accordance with an artifacting scheme that is known by the authentication server and that is changed periodically, wherein the device-specific audio artifact comprises a distinct characteristic comprising a type and a specification of the microphone used to record the statement by the user, and wherein the user is never made aware of the artifacting scheme; and transmitting the speech input to the authentication server via the data session.