Eric Butler
The developer behind Firesheep, the add-on that shamed the web into no longer sending login cookies in cleartext.
In October 2010 Butler demonstrated Firesheep at ToorCon in San Diego. It was a Firefox add-on that listened on open Wi-Fi, picked up session cookies for Facebook, Twitter and a dozen other services, and let the user log in as the victim with a double-click. The technique — session hijacking — was old and well understood; what was new was that it now required zero skill.
That was precisely the intent. Butler wanted to force HTTPS for the whole session, not just the login page, and over the following years Facebook, Twitter and other big services moved to encrypted sessions. Few security tools have achieved so much per line of code.