Abstract: Techniques for simplifying an authentication process from the viewpoint of a user while providing improved security to the many users currently employing no or weak security techniques. In logging into a web site hosted by a web server, a session begins by a user connecting and logging in with a device, such as a personal computer. Rather than a user name and password approach which is presently typical, the personal computer communicates with another user device, such as a smart phone. In one approach, an encoded acoustic signal is employed for this communication. The smart phone securely communicates with an authentication server which informs the web server whether the user has been authenticated or not.