Signature

Introduction

handwriting_compare.gif

Dynamic Signature Verification refers to the process of analyzing one’s signature according to the speed, pressure, and timing that the user takes to complete the signature.[1] The process is ideal for security purposes because it allows a frequently used writing (the signature) that is unique to each user based upon the amount of time and effort that they specifically put into their writing.

History

Signatures date back to the early beginnings of written language, which began in the Sumerian civilization.[2] It wasn’t until the Romans, under Valentitian III, began using the subscripto(a short phrase used to verify wills), that the signature had its birth. It quickly spread to other legal documents as a unique verification tool to ascertain several key elements: message authentication, message/data integrity, and non-repudiation (legal aspect of events).[3] From this base, the signature has become a staple of western civilization, to the point that today, the signature is a legally binding entity.

Advantages

The key advantage to this particular system of behavioral biometrics is that it is based on an already accepted form of identification. Incorporation of a security system based on Dynamic Signature Verification would require a certain amount of investment in equipment and software to analyze the inputs, but no real cost to train people on how to input signals. At the same time, it is reliant upon unique characteristics that are not easily duplicable, with even the same users having slight (neglible) differences between their own signatures. Many companies, such as IBM, are already offering software that provides this service, easily comparing the input signature to six given templates by the authenticated user. Not only does it boast a low total error rate (1.5%) but it also requires little time (1 sec/signature), cheap equipment cost, and low storage space.[4]

Applications

signaturepad

Signature Verification itself is used and has been successfully incorporated into the public domain. Each time a user signs on a digital notepad to approve a credit card transaction, they are using a form of signature verification. The difference though is that this form does not take into account the pressure, timing, and speed with which the user inputs the signal, it only compares the input signature to the one on file. This is due to the simplicity of the system, which often uses only a simple scanner. Thus a forger who can reasonably reproduce the signature of a copy submitted electronically can easily be mistaken for the authentic. Dynamic Signature Verification would require the use of a scanner, a camera to observe how the signature is being made(speed and timing), and a pen with sensors or that uses ultrasonic sensing to observe the pressure. By incorparating these elements into the observed cateogory, the percentage of successful forging attempts is significantly reduced.

Bibliography
1. Understanding Signature Verification. 2007. http://www.findbiometrics.com/Pages/signature%20articles/signature_1.html Retrieved 4/4/08
2. A Comparison of Digital and Handwritten Signatures. Fillingham, David. 1997. http://www-swiss.ai.mit.edu/6805/student-papers/fall97-papers/fillingham-sig.html . Retrieved 4/408
3. Legally Resilient Signatures: A Middle-Age Approach to a Digital Age Problem. Rice, Matthew E. 2005. http://www.cs.fsu.edu/research/reports/TR-050417.pdf Retrieved 4/4/08
4. Online Signature Verification. IBM. http://www.haifa.il.ibm.com/projects/image/sv/ Retrieved 4/4/08
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