Biometrics

Under 21 CFR 11, an electronic signature can be based on biometrics, and then it must be designed so that only the real owner can use it.

(3) Biometrics means a method of verifying an individual's identity based on measurement of the individual's physical feature(s) or repeatable action(s) where those features and/or actions are both unique to that individual and measurable.

21 CFR, 11.3