  Since the demise of the password was predicted in 2004, different attempts in
industry and academia have been made to create an alternative for the use of
passwords in authentication, without compromising on security and user
experience. This review examines password-less authentication schemes that have
been proposed since after the death knell was placed on passwords in 2004. We
start with a brief discussion of the requirements of authentication systems and
then identify various password-less authentication proposals to date. We then
evaluate the truly password-less and practical schemes using a framework that
examines authentication credentials based on their impact on user experience,
overall security, and ease of deployment. The findings of this review observe a
difficulty in balancing security with a user experience compared to that of
passwords in new password-less schemes, providing the opportunity for new
applied research to leverage existing knowledge and combine technologies and
techniques in innovative ways that can address this imbalance.
