Over 2000 years ago, Aristotle noticed the connection between handwriting and personality, but the first manuscript, describing the correlation between character and handwriting, was not published until 1622 at the University of Bologna. How we make loops in letters; align upper, middle, and lower sections of text; space letters, and other characteristics of writing are inherent to each individual. Accordingly, a signature, or the way people write their names, is unique and cannot be repeated by others. This phenomenon originated a centuries-old tradition for important documents to be signed as proof of their authenticity. Simultaneously, for centuries, visual signature verification served as a reliable and efficient means to detect fraud.
Today the signature is still acknowledged as a principal means of authenticating financial, and other, business transactions. People use signatures every day to sign checks, to authorize documents and contracts, to validate credit card transactions, etc. The number of signed paper documents has increased tremendously; simultaneously the growth of fraud through forgery has become one of the biggest security problems challenging almost any large modern organization, including insurance companies, banks and other financial and government institutions.
Comprehensive signature verification systems analyze two different areas of an individual’s signature: the specific features of a static image of one’s signature and the specific characteristics during the process of signing. This article will cover the second type, which embraces applications that allow for tracking the motion of signing one’s name at the point of presentation. This kind of biometric system that treats the signature as a series of movements is often called online or dynamic.
The key to the online verification of the Get Digital signature authenticity of questionable signatures lies in the reconstruction of the writing motion and its elements. Signing is a reflex action based on prior repeated experience (training) and not influenced by deliberate muscular control. In particular, when signing, the hand often moves faster than an individual could volitionally control it to move through hand-muscle coordination. The practiced and natural motion of the original signer would be required to repeat the signature pattern. A copy machine or an expert forger may be able to duplicate what a signature looks like, but it is virtually impossible to mimic such unique behavioral patterns and characteristics of the original signer as succession of touches to the writing surface, speed, acceleration, and pressure.
Thus, for dynamic signature verification a handwritten signature is recorded/captured using a variety of pen-enabled devices such as digitizing tablets, membrane touchpads, capacitive touchpads, LCD touchscreens, computer displays or other contact-sensitive technologies. During the act of signing, a signature is captured and elements and behavioral characteristics that make it unique and identifiable are derived. Signature verification checks biometric characteristics of a questionable signature against biometric characteristics of reference signature (s). The analysis can be executed either in real-time or after signing. Behavioral characteristics of the signing process unambiguously distinguish an individual and make it feasible to create robust signature verification systems. Based on this approach, a number of dynamic signature verification products demonstrate similar efficiency, often a direct function of the quality of the writing tablet utilized.