  This paper proposes three measures to quantify the characteristics of online
signature templates in terms of distinctiveness, complexity and repeatability.
A distinctiveness measure of a signature template is computed from a set of
enrolled signature samples and a statistical assumption about random
signatures. Secondly, a complexity measure of the template is derived from a
set of enrolled signature samples. Finally, given a signature template, a
measure to quantify the repeatability of the online signature is derived from a
validation set of samples. These three measures can then be used as an
indicator for the performance of the system in rejecting random forgery samples
and skilled forgery samples and the performance of users in providing accepted
genuine samples, respectively. The effectiveness of these three measures and
their applications are demonstrated through experiments performed on three
online signature datasets and one keystroke dynamics dataset using different
verification algorithms.
