Privacy-Protecting Techniques for Behavioral Biometric Data: A Survey
This survey addresses privacy protection for individuals whose behavioral data is processed, but it is incremental as it consolidates existing knowledge without introducing new methods.
The paper systematically reviews anonymization techniques for behavioral biometric data, such as voice and gait, to protect privacy against sensitive inferences, finding that some traits are well-studied while others are neglected and evaluation methods need improvement.
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.