Biometric authentication systems have the potential to take the place of passwords. But there are a lot of considerations before taking these systems into use. When should they be used, and how? What are the risks, and when should biometrics be approached with skepticism? Vic Harkness and Tom Van de Wiele discuss the advantages and disadvantages of biometric authentication systems, some of the wackiest ways our bodies can be measured, and why layered security still works best.