17. The apparatus of claim 14 , wherein the at least one processor is further programmed to perform: comparing the voice print of the text-dependent audio sample and the characteristics of the text-independent audio sample.
14. An apparatus comprising: at least one machine-readable medium storing a plurality of voice-prints corresponding to voice characteristics of respective enrolled users; and at least one processor programmed to perform: providing a first prompt to obtain a text-dependent audio sample from a user at an evaluation stage; providing a second prompt to obtain a text-independent audio sample from the user at the evaluation stage; and making an authentication decision about the user based, at least in part, on results of a comparison between characteristics of the text-dependent audio sample and a voice print of an enrollment audio sample received at an enrollment stage and a comparison between a voice print of the text-dependent audio sample and characteristics of the text-independent audio sample.