Patent ID: 7106888

Claim:
A method of enabling user interaction with computer software running in a computer system via: an interface surface displaying information relating to the computer software including a visible signature region corresponding to a signature field relating to the computer software, the interface surface having coded data disposed thereon both inside and outside the signature region, wherein all of the coded data is indicative of its own position relative to the interface surface and wherein the coded data located inside the signature region is further indicative of the signature field; and a sensing device which, when placed in an operative position relative to the interface surface, senses at least some of the coded data and generates indicating data indicative of the signature field using at least some of the sensed coded data, and generates movement data indicative of the sensing device's movement, and wherein the sensing device is linked, during a registration process, to an authorized user using a secret key-exchange key and first digital ink consisting of the authorized user's handwritten signature; the method including the steps of, in the computer system: (a) receiving the indicating data from the sensing device; (b) receiving the movement data from the sensing device, the movement data representing second digital ink consisting of a user's handwritten signature; (c) identifying the signature field on the basis of the indicating data; (d) verifying the user's handwritten signature by comparing the second digital ink with the first digital ink; (e) generating, in the computer system and using a signature key of the user that is a private key, a digital signature of digital content related to the computer software; and (f) operating the computer software at least partly in reliance on the movement data, and in accordance with instructions associated with the signature field.