Tracking Traitors in Web Services via Blind Signatures

Abstract

This paper presents a method and its implementation, built on the blind signatures protocol, to trace users sharing their licenses illegally when accessing services provided through Internet (Web services, Streaming, etc). The method devised is able to identify the legitimate user from those users who are illegally accessing services with a shared key. This method is robust when detecting licenses built with no authorization. An enhancement of the protocol to identify the last usage of a certain license is also provided, allowing to detect a traitor when an unauthorized copy of a license is used.