Liveness Assurance in Voice Authentication

The process of verifying whether the voice sample presented to an authentication system is real (i.e., alive), or whether it is replayed or synthetic, and thus fraudulent. When authentication through a voice authentication system is requested, it is important to be sure that the person seeking the authentication actually provides the required voice sample at the time and place of the authentication request. The voice is presented live like that of a radio presenter during a live broadcast as distinct from a recorded audio tape. In contrast, an impostor who seeks authentication fraudulently could try to play an audio recording of a legitimate client or synthesized speech that is manufactured to resemble the speech of a legitimate client. Such threats to the system are known as replay attack and synthesis attack, respectively. Liveness assurance uses a range of measures to reduce the vulnerability of a voice authentication system to the threats of replay and synthesis attack.