Patent ID: 8601552

Claim:
A method by which a computer system authenticates a user, the method comprising: displaying a plurality of unique elements to a user on a touch-sensitive display device at an authentication time, including, for each unique element, displaying a unique color of that unique element on a distinct portion of the display device; receiving, at the authentication time, a first set of points corresponding to a first sweeping motion performed by the user with respect to the display device, including: receiving, at the authentication time, a first point defined by an initial location touched by a first touching implement of the user on the touch-sensitive display screen; and receiving all subsequent points defined by all subsequent locations touched by the first touching implement of the user on the touch-sensitive display screen until the first touching implement of the user loses contact with the touch-sensitive display screen, the first point and the subsequent points defining the first sweeping motion; determining a first pair of unique elements of the plurality of unique elements defined by endpoints of the first sweeping motion; receiving a second set of points corresponding to a second simultaneous sweeping motion performed by the user with respect to the touch-sensitive display screen using a second touching implement distinct from the first touching implement; determining a second pair of unique elements of the plurality of unique elements defined by endpoints of the second sweeping motion, the second pair of unique elements being distinct from the first pair of unique elements; and authenticating the user only if both the first pair of unique elements and the second pair of unique elements are associated for authentication purposes with the user; wherein the first touching implement is selected from a group consisting of a finger and a stylus and the second touching implement is selected from another group consisting of a finger and a stylus.