The paper is organized as follows. In Section II a characterization
of a generic EEG signal acquisition system is
given along with a characterization of the brain rhythms.
In Section III the EEG signal acquisition protocols used in
biometric oriented applications are described. In Section IV
the different characteristics of EEG biometrics are deeply analyzed.
State-of-the-art approaches are described in Section V where an analysis on the employed protocols, the feature
extraction algorithms, the classification algorithms, and the
database structure is conducted. In Section VI open issues on
the design of EEG based biometric systems are detailed and
conclusions are finally drawn in Section VII.