Signing documents is something that most every adult is familiar with.  In our personal lives we sign everything from personal checks to birthday cards.  In the business world we sign things such as expense accounts and other official documents.  This lends itself well for signature recognition to be used as a means of biometric verification in electronic commerce.  This type of signature identification is different however from the normal two-dimensional signature that one would find on a form or document.  Biometric signature recognition operates in a three-dimensional environment where, not only is the height and width of pen strokes measured, but also the amount of pressure applied in the pen stroke to measure the depth that would occur as if the stroke was made in the air.  This helps to reduce the risk of forgery that can occur in two-dimensional signatures.

    One drawback to this form of encryption is that people do not always sign documents in exactly the same manner.  The angle at which they sign may be different due to seating position or due to hand placement on the writing surface.  Therefore, even though it is three dimensional which adds to its ability to discern impostors, it is not as accurate as other forms of biometric verification.

    These types of systems are not as expensive as some of the higher end systems such as iris scanners, and they are priced more in the range of voice and fingerprint scanners which makes them quite affordable for network use.