Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for a biometric authentication system. In one aspect, a method includes capturing pressure measurement data as a sequence of pressure maps as the user applies pressure to the pressure sensing device; determining a dynamic pressure signature for the user based on the pressure measurement data, the dynamic pressure signature including a temporal sequence of the pressure maps; and authenticating the user based on a comparison of the dynamic pressure signature to an initial dynamic pressure signature.