Digital pen system

摘要

A digital pen system comprising a pen 8 adapted to mark a medium 2 and a sensor 12 arranged to determine the position on the medium 2 of a mark made by the pen 8 , the system being arranged to identify a plurality of different areas 500 on the medium 2 and being further arranged to authenticate a user in dependence upon authentication data input by the user, the authentication data having a value dependent upon the order in which a group of the plurality of different areas 500 of the medium 2 are marked by the pen 8.