Automatic verbal information verification for user authentication

Traditional speaker authentication focuses on speaker verification (SV) and speaker identification, which is accomplished by matching the speaker’s voice with his or her registered speech patterns. In this paper, we propose a new technique, verbal information verification (VIV), in which spoken utterances of a claimed speaker are verified against the key (usually confidential) information in the speaker’s registered profile automatically to decide whether the claimed identity should be accepted or rejected. Using the proposed sequential procedure involving three question-response turns, we achieved an error-free result in a telephone speaker authentication experiment with 100 speakers. We further propose a speaker authentication system by combining VIV with SV. In the system, a user is verified by VIV in the first four to five accesses, usually from different acoustic environments. During these uses, one of the key questions pertains to a pass-phrase for SV. The VIV system collects and verifies the pass-phrase utterance for use as training data for speaker model construction. After a speaker-dependent model is constructed, the system then migrates to SV. This approach avoids the inconvenience of a formal enrollment procedure, ensures the quality of the training data for SV, and mitigates the mismatch caused by different acoustic environments between training and testing. Experiments showed that the proposed system improved the SV performance by over 40% in equal-error rate compared to a conventional SV system.