Worth reading in this area:
<a href="https://medium.com/@ninjudd/passwords-are-obsolete-9ed56d483eb" rel="nofollow">https://medium.com/@ninjudd/passwords-are-obsolete-9ed56d483...</a>
<a href="https://dzone.com/articles/how-passwordless-authentication-works" rel="nofollow">https://dzone.com/articles/how-passwordless-authentication-w...</a>