A method of operating an access control system , the method comprising: - recording fingerprint data corresponding to one or more fingers of a particular authorized person; - recording a sequence of finger positions for the particular authorized person ; - providing drive signals to a fingerprint sensor and a plurality of drive signal injection points at least partially surrounding the fingerprint sensor with each drive signal injection point corresponding to an angular position about the fingerprint sensor , each drive signal injection point is provided with a unique drive signal and the drive signal corresponding to each drive signal injection point is distinguishable from the drive signal corresponding to each other drive signal injection point ; - receiving (1102-1104) a series of fingerprint signals from the fingerprint sensor , wherein each fingerprint signal corresponds to at least one drive signal coupled to the fingerprint sensor by a finger when the fingerprint signal is received; - determining a sequence of angular positions corresponding to sequential fingerprint signals in the series, wherein the angular position of a fingerprint signal is determined by determining the at least one drive signal to which that fingerprint signal corresponds; - determining if each of the fingerprint signals corresponds to the recorded fingerprint data; - determining if the sequence of angular positions corresponds to the recorded sequence of finger positions; and - if the fingerprint signals correspond to the recorded fingerprint data and the sequence of angular positions corresponds to the recorded sequence of fingerprint positions, then providing an authorization signal. - recording fingerprint data corresponding to one or more fingers of a particular authorized person; - recording a sequence of finger positions for the particular authorized person ; - providing drive signals to a fingerprint sensor and a plurality of drive signal injection points at least partially surrounding the fingerprint sensor with each drive signal injection point corresponding to an angular position about the fingerprint sensor , each drive signal injection point is provided with a unique drive signal and the drive signal corresponding to each drive signal injection point is distinguishable from the drive signal corresponding to each other drive signal injection point ; - receiving (1102-1104) a series of fingerprint signals from the fingerprint sensor , wherein each fingerprint signal corresponds to at least one drive signal coupled to the fingerprint sensor by a finger when the fingerprint signal is received; - determining a sequence of angular positions corresponding to sequential fingerprint signals in the series, wherein the angular position of a fingerprint signal is determined by determining the at least one drive signal to which that fingerprint signal corresponds; - determining if each of the fingerprint signals corresponds to the recorded fingerprint data; - determining if the sequence of angular positions corresponds to the recorded sequence of finger positions; and - if the fingerprint signals correspond to the recorded fingerprint data and the sequence of angular positions corresponds to the recorded sequence of fingerprint positions, then providing an authorization signal. <EOS>