(1)
A common
authentication technique whereby an individual is prompted (the
challenge) to provide some private information (the
response). Most security systems that rely on
smart cards are based on challenge-response. A user is given a code (the challenge) which he or she enters into the smart card. The smart card then displays a new code (the response) that the user can present to log in.
(2) In biometrics, challenge response is the
term used to describe the method by which the
identification of a person is detected based on voluntary or involuntary
responses. Challenge response is a type of biometric system security.