Passwordless Authentication in Phoenix

I would like to remind you all that email is an unsafe medium. You’re not sending electronic letters, you’re sending electronic postcards.
When you send a ‘forgot password’ email, it can normally only be used to reset a password once. On top of that, the better services also time these links out after a few hours.

With magic links, people will get grumpy if you time their old link out, so all old links should continue working for a very long time.

But in both cases, I have the feeling that too much trust is put in the medium that is email. But solving this problem is a bit a chicken-and-egg problem, as techniques like PGP are somewhat of a hassle to set up and need a password themselves.

fyi I updated the article incorporating your idea and mentioning this thread – thanks again!

Nice post!

A feedback (or more like a question): from a security point of view, would it be better not to let the user know whether or not the email is found on the DB? Just notify the user as if the email were successfully sent, but silently swallow the error on the server-side (you don’t actually send the email). That way any potential attacker wouldn’t be able to guess who’s registered on your system.

UX-wise it would pose a problem if the user mistype their email, but that can be circumvented by just printing back the email to the client (“We have sent a magic login link to foo@bar.com. See you soon!”).

But of course implementing it this way doesn’t mean you can left out the maximum number of tries validation (and possibly captchas) for preventing brute-force attacks and using your system as spam mail generator