A method for validating the identity of a user using a computer system in cooperation with a pointing device, hereinafter referred to as PD, that is operated by the user, comprising the steps of: a) displaying a virtual pad via said computer system, wherein the virtual pad comprises a background image and at least one object positioned on the background image; b) operating the PD which corresponds to a cursor appearing on the virtual pad, wherein user operation comprises using the cursor to generate events selected from drawing lines, positioning the cursor relative to the at least one object, repositioning the at least one object, dragging the at least one object, clicking on the at least one object, and selecting the at least one object; c) sampling a plurality of the events in step (b) so as to obtain data corresponding to positions of the cursor relative to the background image; d) extracting features from the sampled PD signature, wherein the sampled PD signature comprises a sequence of position vectors, each position vector comprising sample coordinates, a sample time and a PD mode parameter value; e) comparing the features extracted from the sampled PD signature with a previously stored PD reference signature, the stored PD reference signature being known to represent the identity of the user, the comparison step comprising comparing the features extracted in step (d) with features relating to the stored PD reference signature; and f) validating said identity of said user in response to the comparison step of part (e) wherein the comparison step comprises comparing the sampled PD signature with the stored PD reference signature, via i) placing nodes at predetermined distances along a signature curve of the stored PD reference signature; ii) migrating the nodes from i) to minimum cost locations along or nearby the signature curve of the stored PD reference signature using a cost minimization technique; iii) positioning nodes from ii) with signature curve of the sampled PD signature and migrating the nodes from ii) towards the signature curve of the sampled PD signature using the cost minimization technique; iv) comparing the geometry of the migrated nodes in iii) with the geometry of nodes in ii). a) displaying a virtual pad via said computer system, wherein the virtual pad comprises a background image and at least one object positioned on the background image; b) operating the PD which corresponds to a cursor appearing on the virtual pad, wherein user operation comprises using the cursor to generate events selected from drawing lines, positioning the cursor relative to the at least one object, repositioning the at least one object, dragging the at least one object, clicking on the at least one object, and selecting the at least one object; c) sampling a plurality of the events in step (b) so as to obtain data corresponding to positions of the cursor relative to the background image; d) extracting features from the sampled PD signature, wherein the sampled PD signature comprises a sequence of position vectors, each position vector comprising sample coordinates, a sample time and a PD mode parameter value; e) comparing the features extracted from the sampled PD signature with a previously stored PD reference signature, the stored PD reference signature being known to represent the identity of the user, the comparison step comprising comparing the features extracted in step (d) with features relating to the stored PD reference signature; and f) validating said identity of said user in response to the comparison step of part (e) wherein the comparison step comprises comparing the sampled PD signature with the stored PD reference signature, via i) placing nodes at predetermined distances along a signature curve of the stored PD reference signature; ii) migrating the nodes from i) to minimum cost locations along or nearby the signature curve of the stored PD reference signature using a cost minimization technique; iii) positioning nodes from ii) with signature curve of the sampled PD signature and migrating the nodes from ii) towards the signature curve of the sampled PD signature using the cost minimization technique; iv) comparing the geometry of the migrated nodes in iii) with the geometry of nodes in ii). i) placing nodes at predetermined distances along a signature curve of the stored PD reference signature; ii) migrating the nodes from i) to minimum cost locations along or nearby the signature curve of the stored PD reference signature using a cost minimization technique; iii) positioning nodes from ii) with signature curve of the sampled PD signature and migrating the nodes from ii) towards the signature curve of the sampled PD signature using the cost minimization technique; iv) comparing the geometry of the migrated nodes in iii) with the geometry of nodes in ii).