Multifactor Authentication

2.1.6. Hand Geometry

Some systems employ the analysis of the physical shape of a hand to authenticate the user. Initially, pegs were utilized to validate the subject, but the usability of such methods was low. Further on, the flatbed scanner was used to obtain the image without the need to fix the user’s hand in one specific position. Today, some systems utilize conventional cameras not requiring close contact with the capture surface. This approach is, however, not very robust to the environment. Some vendors apply so-called photoplethysmography (PPG) to determine whether a wearable device (e.g., a smartwatch) is currently on its user’s wrist or not. The process is similar to the one followed when measuring heart rate.