Attempts to automate the authentication of this credential go back for a couple of decades. Development has been centered around signature dynamics, which is considerably more difficult to copy. The Inforite Corp in San Mateo, Calif., produces a signature-dynamics verification system. The finger is placed on a contoured glass pad and scanned optically. The process only takes a few seconds and requires no hand scrubbing afterward.
Hand geometry is another biometric credential.
The relative lengths of the fingers and the translucency of the webs between the fingers are measured in Stellar's Identimat System. Although large and bulky, this system has the most field experience. It has been used for many years by the military and other high-level security users. The pattern of blood vessels on the retina of the eye is so complex and random that no two are alike. EyeDentify Inc., offers a retinal eye scan terminal designed to overcome the natural reluctance of people to the concept of using their eyeballs as credentials.