Dynamic Signature Verification forgery level

This project aims at understanding the levels of forgery that exist for dynamic signature verification. Here is what we propose:

levels 0-2 are "blind" forgeries (forger does not have access to copy of signature)
levels 3&4 are static forgeries (forger only has access to signature after it is signed, does not observe signature creation)
levels 5&6 are observation based forgeries (forger actually observes signature creation)
levels 7&8 are assited forgeries (either victim or technology assisted forgeries)

Possible new definitions of forgery levels

0 = zero effort, forger signs a random name
1 = forger has heard name but not seen it in print (does not know spelling Steven vs. Stephen or Jon vs. John)
2 = forger has seen name in print such as a phone directory or business card but has not seen signature
3 = single sample, forger has access to a single sample of victim's signature (receipt or check)
4 = multiple sample, forger has access to multiple samples of victim's signature (possibly additional sample of writing such as a hand written note)
5 = single observation, forger has observed the victim signing his or her name once
6 = multiple observation, forger has observed the victim signing his or her name multiple times (possibly video tape of signing replayed over and over)
7 = "victim assisted" forgery, victim intentionally coaches forger to dynamically immitate signature
8 = "technology assisted" fogery, forger has access to digitizer output of victim's signature and is allowed multiple practice attempts to immitate speed, pressure and curves

The Relation of the Human Biometric Sensor Interaction to Dynamic Signature Verification

Abstract: Many different types of point of sale digitizers are available on the market, each having their own particular characteristics such as size of the signing area, sampling speeds, and ergonomic design. Some digitizers provide real-time feedback in the form of electronic ink, while others provide none. The purpose of this paper is to establish whether there are any differences in the signing behaviors of an individual when the signing space for the signature is changed, and whether the features are significantly different depending on the presence or lack of real-time electronic ink feedback. This research was undertaken to provide information to the biometric community, specifically the ISO biometrics testing committee regarding modality testing of dynamic signature verification (DSV).

Methodology: Two different studies were undertaken to understand the issues related to the act of signing in different sizes of signing areas, as well as signing with or without ink feedback. For the first study, the subjects signed their names once in each of three different size signing areas on a Wacom Intuos™ digitizer. The three signing areas were 150mm x 200mm, 55mm x 55mm, and 55mm x 37mm. The features were extracted from the digitizer, and were subsequently analyzed. The second study involved a different set of individuals who signed their name on a digitizer that offered visible ink feedback (see Fig. 2, left) and on a digitizer that offered no visible ink feedback (see Fig. 2, right). Features were extracted from the digitizers and subsequently analyzed using a two-sample t-test. Table I outlines the feature variables used in the second study with the ink/no ink feedback digitizers.

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