Privacy-Protecting Techniques for Behavioral Biometric Data: A Survey

TL;DR

This survey reviews privacy-preserving techniques for behavioral biometric data, highlighting existing solutions, their strengths and weaknesses, and identifying gaps in research and evaluation methods.

Contribution

It systematically categorizes and compares anonymization methods for various behavioral traits, providing a comprehensive overview and identifying research gaps.

Findings

Voice biometrics receive most research attention.

Eye-gaze and brain activity are underexplored.

Evaluation methods for anonymization techniques need improvement.

Abstract

Our behavior (the way we talk, walk, act or think) is unique and can be used as a biometric trait. It also correlates with sensitive attributes like emotions and health conditions. Hence, techniques to protect individuals privacy against unwanted inferences are required, if such data is planned to be processed. To consolidate knowledge in this area, we systematically review applicable anonymization techniques. We taxonomize and compare existing solutions regarding privacy goals, conceptual operation, advantages, and limitations. We review anonymization techniques for the behavioral biometric traits of voice, gait, hand motions, eye-gaze, heartbeat (ECG), and brain activity (EEG). Our analysis shows that some behavioral traits (e.g., voice) have received much attention, while others (e.g., eye-gaze, brain activity) are mostly neglected. We also find that the evaluation methodology of behavioral anonymization techniques can be further improved.