UltraSonic Watch

Two-factor authentication (2FA) provides an extra layer of security as it requires two pieces of evidence to be provided to an authentication mechanism before granting access to a user. However, people do not prefer 2FA; a reason for this is that 2FA requires performing extra actions. In this late-breaking work, we present UltraSonic Watch which provides a seamless 2FA through ultrasound. We report a small-scale within-subjects study (N=30) which investigates the performance of UltraSonic Watch and the participants' experience (in terms of perception, preference, and willingness to adopt). The results are promising as they revealed that ultrasound can be used to provide an efficient 2FA mechanism, transparent to the users, who are positive in adopting such an approach to increase the security of the authentication process.