A form of authentication whereby the smart card is loaded with a DES key used in response to a random number generated by the system and sent to the card when the card is inserted in the card reader.
A method that authenticates that a human responded to an email challenge message and upon completion of the challenge, the original email that triggered the challenge is delivered to the recipient.
A form of authentication in which the system seeking authentication sends out a random "challenge". The object (e.g. the card or terminal) being authenticated performs a calculation on the challenge and responds with a result, from which the challenger can ascertain the authenticity or otherwise of the object. This method of authentication is much more secure than a simple password or other unvarying response.
A spam prevention technique which requires unknown or untrusted senders to perform a manual step in order to send messages to a given recipient. The manual "response" step is designed to be impossible to automatically perform, with the idea is that it is impractical for senders of bulk email to manually gain access to individual mailboxes.
An authentication method that requires a human to respond to an email challenge message before the original email that triggered the challenge is delivered to the recipient. This method is sometimes used to cut down on spam since it requires an action by a human sender.
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.
A common authentication technique for smart cards whereby an individual is prompted (the challenge) to provide some private information (the response). The in-built security system presents a code (the challenge) to the user, which he or she enters into the smart card. This generates a new code (the response) that the user can present to log in.
