I built and open-sourced something like this a while ago: http://nopassword.alexsmolen.com http://nopassword.alexsmolen.com HN thread here: https://news.ycombi

I built and open-sourced something like this a while ago: http://nopassword.alexsmolen.com http://nopassword.alexsmolen.com HN thread here: https://news.ycombinator.com/item?id=4570600 https://news.ycombinator.com/item?id=4570600 It's a great concept, but like any new authentication mechanism there's a usability and security cost due to the lack of familiarity. Plenty of authentication mechanisms are "better" than passwords, but passwords are well-understood and flexible, which is a huge advantage for almost all sites.