Libraries and Implementations:
Your browser transfers an encrypted verifier based your password. But it does not send the password itself.
<% if @user %>You enter your password - your browser exchanges encrypted data with the site to check if it was the right one.
<% if @user && @user.active %>You can see from the logs that your password was not send. The login process is different each time so it can't be replayed.
<%= button_link(:verify, :primary => @user && @user.active) %>