Biometrics refers to the measuring and analyzing of distinctive physiological and behavioral human features, for identification and verification purposes. One of the behavioral human features is the Electroencephalogram (EEG) brain signals; EEG are the electrical activity measurements of the brain recorded from the scalp surface after being picked up by electrodes. They cannot be captured remotely or obtained later, as it happen with traditional biometrics such as fingerprints, so they are "secret" due to their nature and robust to spoof attacks.