A method of gaining access to goods or services includes the steps of: writing a signature within a verification zone of an encoded base using an optically imaging pen having a marking nib; optically reading a sequence of absolute locations corresponding to the signature from the encoded base; and checking if the locations are within a region registered as belonging to an authorized user. Access to the goods or services is granted if the location is within the region belonging to the authorized user and the sequence of locations corresponds to a previously registered signature of the authorized user, otherwise access is denied.