AUTHENTICATION METHOD OF RANDOM PARTIAL DIGITIZED PATH RECOGNITION WITH A CHALLENGE BUILT INTO THE PATH

An interactive method for authentication is based on two shared secrets, including a first shared secret in the form of an ordered path on the frame of reference, and a second shared secret in the form of locations on the frame of reference at which characters identifying a subset of the ordered path are to be displayed. An instance of the frame of reference comprises a set of characters which is arranged in a random or other irregular pattern. Authentication requires that a user enter the characters in the displayed instance of the frame of reference found in the locations in the random subset of the ordered path by indicating characters either in these locations, or any other locations having the same characters. Thus, a secret challenge identifying the random partial subset is embedded within the displayed instance of the graphical representation of the frame of reference.