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Grading of Signature Strength against Forgeries for a Touch-Screen application

IP.com Disclosure Number: IPCOM000235003D
Publication Date: 2014-Feb-23
Document File: 2 page(s) / 46K

Publishing Venue

The IP.com Prior Art Database

Abstract

This disclosure discusses the domain of biometric authentication. More specifically, using a person's signature or handwriting on a touch screen device, in order to verify the identity of the person. The process involves having the person provide a few samples of the signature during enrollment, and later compare the signature to the enrollment set. In this article we suggest a method to grade the score of a sample, so that we can differentiate between the real signature, and a forgery.

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Grading of Signature Strength against Forgeries for a Touch-Screen application

Grading of Signature Strength against Forgeries for a Touch -

This disclosure discusses the domain of biometric authentication. More specifically, using a person's signature or handwriting on a touch screen device, in order to verify the identity of the person.

The process involves having the person provide a few samples of the signature during enrollment, and later compare the signature to the enrollment set.

In this article we suggest a method to grade the score of a sample, so that we can differentiate between the real signature, and a forgery.

    Password strength is very common nowadays. Many websites that require log-in passwords present to the users the strength of their passwords in order to help them choose a strong password. We wish to have a similar grading to the strength of signatures against forgery.

    A signature on a touch screen device is in fact a set of chronologically ordered sampling points. Each point has x,y coordinates, a time stamp, and the radius of the finger which is relative to the pressure applied in that point.

The signature strength depends on the following factors:


1. Signature length (number of sampling points).


2. Variability of the direction (the angle between sequential sampling points).


3. Variability of the velocity (the length between sequential sampling points).


4. Variability of the pressure (the radius of the finger).

A strong signature should have high values in all these factors.

The importance of the first factor is obvious, and similar to the case of regular password strength.

    An example for the importance of the second factor is a straight line, for which the value of this factor is zero, and indeed it is very easy for forgery. As the signature

has a more complex shape it is harder for forgery.

However a straight line (or almost straight) can still became harder for forgery if the velocity and pressure a...