Review of 'Technological, legal, and sociological summary of biometric technology usage'

The manuscript represents an overview article suitable for readers who want to get acquainted with the issue of biometric authentication in a broader context - not only from the technology but also from the position of biometrics in the context of the law and user awareness and acceptance.

The first part is devoted to the basic introduction of biometric authentication. It explains the basic concepts and introduces the most commonly used technologies. The next part focuses on relevant European legislation that applies to biometric authentication - it primarily focuses on data protection (GDPR, etc.) and covers other standards. The last part is dedicated to the user perspective. The authors present how users perceive biometric authentication regarding its security and usability. New data from the Czech Republic is also included.

Although the paper does not present any major new findings, it is a comprehensive work that adequately presents the whole issue. I welcome the inclusion of other aspects, as the legal framework and applicable security must also be considered for effective and correct technology deployment.

Minor comments/questions:

1. You discuss the need for active consent in the context of GDPR. However, this can not be obtained (and usually is not obtained) for video monitoring services in public places, which usually adopt face recognition. What is the legal basis for this use case?
2. While I appreciate the size of the demographic group for the sociological survey from 2018, I am completely missing the demography description for the latest preliminary research from 2020. Without this information, there is no possibility of assessing the significance of the conclusions.