Dictionary Attacks on Speaker Verification

In this paper, we propose dictionary attacks against speaker verification - a novel attack vector that aims to match a large fraction of speaker population by chance. We introduce a generic formulation of the attack that can be used with various speech representations and threat models. The attacker uses adversarial optimization to maximize raw similarity of speaker embeddings between a seed speech sample and a proxy population. The resulting master voice successfully matches a non-trivial fraction of people in an unknown population. Adversarial waveforms obtained with our approach can match on average 69% of females and 38% of males enrolled in the target system at a strict decision threshold calibrated to yield false alarm rate of 1%. By using the attack with a black-box voice cloning system, we obtain master voices that are effective in the most challenging conditions and transferable between speaker encoders. We also show that, combined with multiple attempts, this attack opens even more to serious issues on the security of these systems

SLIM : Scalable Linkage of Mobility Data

We present a scalable solution to link entities across mobility datasets using their spatio-temporal information. This is a fundamental problem in many applications such as linking user identities for security, understanding privacy limitations of location based services, or producing a unified dataset from multiple sources for urban planning. Such integrated datasets are also essential for service providers to optimise their services and improve business intelligence. In this paper, we first propose a mobility based representation and similarity computation for entities. An efficient matching process is then developed to identify the final linked pairs, with an automated mechanism to decide when to stop the linkage. We scale the process with a locality-sensitive hashing (LSH) based approach that significantly reduces candidate pairs for matching. To realize the effectiveness and efficiency of our techniques in practice, we introduce an algorithm called SLIM. In the experimental evaluation, SLIM outperforms the two existing state-of-the-art approaches in terms of precision and recall. Moreover, the LSH-based approach brings two to four orders of magnitude speedup

Evaluating soft biometrics in the context of face recognition

2013 Summer.Includes bibliographical references.Soft biometrics typically refer to attributes of people such as their gender, the shape of their head, the color of their hair, etc. There is growing interest in soft biometrics as a means of improving automated face recognition since they hold the promise of significantly reducing recognition errors, in part by ruling out illogical choices. Here four experiments quantify performance gains on a difficult face recognition task when standard face recognition algorithms are augmented using information associated with soft biometrics. These experiments include a best-case analysis using perfect knowledge of gender and race, support vector machine-based soft biometric classifiers, face shape expressed through an active shape model, and finally appearance information from the image region directly surrounding the face. All four experiments indicate small improvements may be made when soft biometrics augment an existing algorithm. However, in all cases, the gains were modest. In the context of face recognition, empirical evidence suggests that significant gains using soft biometrics are hard to come by

Advanced Biometrics with Deep Learning

Biometrics, such as fingerprint, iris, face, hand print, hand vein, speech and gait recognition, etc., as a means of identity management have become commonplace nowadays for various applications. Biometric systems follow a typical pipeline, that is composed of separate preprocessing, feature extraction and classification. Deep learning as a data-driven representation learning approach has been shown to be a promising alternative to conventional data-agnostic and handcrafted pre-processing and feature extraction for biometric systems. Furthermore, deep learning offers an end-to-end learning paradigm to unify preprocessing, feature extraction, and recognition, based solely on biometric data. This Special Issue has collected 12 high-quality, state-of-the-art research papers that deal with challenging issues in advanced biometric systems based on deep learning. The 12 papers can be divided into 4 categories according to biometric modality; namely, face biometrics, medical electronic signals (EEG and ECG), voice print, and others

Decision fusion for multi-modal person authentication.

Hui Pak Sum Henry.Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.Includes bibliographical references (leaves [147]-152).Abstracts in English and Chinese.Chapter 1. --- Introduction --- p.1Chapter 1.1. --- Objectives --- p.4Chapter 1.2. --- Thesis Outline --- p.5Chapter 2. --- Background --- p.6Chapter 2.1. --- User Authentication Systems --- p.6Chapter 2.2. --- Biometric Authentication --- p.9Chapter 2.2.1. --- Speaker Verification System --- p.9Chapter 2.2.2. --- Face Verification System --- p.10Chapter 2.2.3. --- Fingerprint Verification System --- p.11Chapter 2.3. --- Verbal Information Verification (VIV) --- p.12Chapter 2.4. --- Combining SV and VIV --- p.15Chapter 2.5. --- Biometric Decision Fusion Techniques --- p.17Chapter 2.6. --- Fuzzy Logic --- p.20Chapter 2.6.1. --- Fuzzy Membership Function and Fuzzy Set --- p.21Chapter 2.6.2. --- Fuzzy Operators --- p.22Chapter 2.6.3. --- Fuzzy Rules --- p.22Chapter 2.6.4. --- Defuzzification --- p.23Chapter 2.6.5. --- Advantage of Using Fuzzy Logic in Biometric Fusion --- p.23Chapter 2.7. --- Chapter Summary --- p.25Chapter 3. --- Experimental Data --- p.26Chapter 3.1. --- Data for Multi-biometric Fusion --- p.26Chapter 3.1.1. --- Speech Utterances --- p.30Chapter 3.1.2. --- Face Movement Video Frames --- p.31Chapter 3.1.3. --- Fingerprint Images --- p.32Chapter 3.2. --- Data for Speech Authentication Fusion --- p.33Chapter 3.2.1. --- SV Training Data for Speaker Model --- p.34Chapter 3.2.2. --- VIV Training Data for Speaker Independent Model --- p.34Chapter 3.2.3. --- Validation Data --- p.34Chapter 3.3. --- Chapter Summary --- p.36Chapter 4. --- Authentication Modules --- p.37Chapter 4.1. --- Biometric Authentication --- p.38Chapter 4.1.1. --- Speaker Verification --- p.38Chapter 4.1.2. --- Face Verification --- p.38Chapter 4.1.3. --- Fingerprint Verification --- p.39Chapter 4.1.4. --- Individual Biometric Performance --- p.39Chapter 4.2. --- Verbal Information Verification (VIV) --- p.42Chapter 4.3. --- Chapter Summary --- p.44Chapter 5. --- Weighted Average Fusion for Multi-Modal Biometrics --- p.46Chapter 5.1. --- Experimental Setup and Results --- p.46Chapter 5.2. --- Analysis of Weighted Average Fusion Results --- p.48Chapter 5.3. --- Chapter Summary --- p.59Chapter 6. --- Fully Adaptive Fuzzy Logic Decision Fusion Framework --- p.61Chapter 6.1. --- Factors Considered in the Estimation of Biometric Sample Quality --- p.62Chapter 6.1.1. --- Factors for Speech --- p.63Chapter 6.1.2. --- Factors for Face --- p.65Chapter 6.1.3. --- Factors for Fingerprint --- p.70Chapter 6.2. --- Fuzzy Logic Decision Fusion Framework --- p.76Chapter 6.2.1. --- Speech Fuzzy Sets --- p.77Chapter 6.2.2. --- Face Fuzzy Sets --- p.79Chapter 6.2.3. --- Fingerprint Fuzzy Sets --- p.80Chapter 6.2.4. --- Output Fuzzy Sets --- p.81Chapter 6.2.5. --- Fuzzy Rules and Other Information --- p.83Chapter 6.3. --- Experimental Setup and Results --- p.84Chapter 6.4. --- Comparison Between Weighted Average and Fuzzy Logic Decision Fusion --- p.86Chapter 6.5. --- Chapter Summary --- p.95Chapter 7. --- Factors Affecting VIV Performance --- p.97Chapter 7.1. --- Factors from Verbal Messages --- p.99Chapter 7.1.1. --- Number of Distinct-Unique Responses --- p.99Chapter 7.1.2. --- Distribution of Distinct-Unique Responses --- p.101Chapter 7.1.3. --- Inter-person Lexical Choice Variations --- p.103Chapter 7.1.4. --- Intra-person Lexical Choice Variations --- p.106Chapter 7.2. --- Factors from Utterance Verification --- p.108Chapter 7.2.1. --- Thresholding --- p.109Chapter 7.2.2. --- Background Noise --- p.113Chapter 7.3. --- VIV Weight Estimation Using PDP --- p.115Chapter 7.4. --- Chapter Summary --- p.119Chapter 8. --- Adaptive Fusion for SV and VIV --- p.121Chapter 8.1. --- Weighted Average fusion of SV and VIV --- p.122Chapter 8.1.1. --- Scores Normalization --- p.123Chapter 8.1.2. --- Experimental Setup --- p.123Chapter 8.2. --- Adaptive Fusion for SV and VIV --- p.124Chapter 8.2.1. --- Components of Adaptive Fusion --- p.126Chapter 8.2.2. --- Three Categories Design --- p.129Chapter 8.2.3. --- Fusion Strategy for Each Category --- p.132Chapter 8.2.4. --- SV Driven Approach --- p.133Chapter 8.3. --- SV and Fixed-Pass Phrase VIV Fusion Results --- p.133Chapter 8.4. --- SV and Key-Pass Phrase VIV Fusion Results --- p.136Chapter 8.5. --- Chapter Summary --- p.141Chapter 9. --- Conclusions and Future Work --- p.143Chapter 9.1. --- Conclusions --- p.143Chapter 9.2. --- Future Work --- p.145Bibliography --- p.147Appendix A Detail of BSC Speech --- p.153Appendix B Fuzzy Rules for Multimodal Biometric Fusion --- p.155Appendix C Full Example for Multimodal Biometrics Fusion --- p.157Appendix DReason for Having a Flat Error Surface --- p.161Appendix E Reason for Having a Relative Peak Point in the Middle of the Error Surface --- p.164Appendix F Illustration on Fuzzy Logic Weight Estimation --- p.166Appendix GExamples for SV and Key-Pass Phrase VIV Fusion --- p.17