  Over the past two decades, biometric recognition has exploded into a plethora
of different applications around the globe. This proliferation can be
attributed to the high levels of authentication accuracy and user convenience
that biometric recognition systems afford end-users. However, in-spite of the
success of biometric recognition systems, there are a number of outstanding
problems and concerns pertaining to the various sub-modules of biometric
recognition systems that create an element of mistrust in their use - both by
the scientific community and also the public at large. Some of these problems
include: i) questions related to system recognition performance, ii) security
(spoof attacks, adversarial attacks, template reconstruction attacks and
demographic information leakage), iii) uncertainty over the bias and fairness
of the systems to all users, iv) explainability of the seemingly black-box
decisions made by most recognition systems, and v) concerns over data
centralization and user privacy. In this paper, we provide an overview of each
of the aforementioned open-ended challenges. We survey work that has been
conducted to address each of these concerns and highlight the issues requiring
further attention. Finally, we provide insights into how the biometric
community can address core biometric recognition systems design issues to
better instill trust, fairness, and security for all.
