A value used in security protocols that is never repeated with the same key. For example, nonces used as challenges in challenge- response authentication protocols generally must not be repeated until authentication keys are changed.
Otherwise, there is a possibility of a replay attack. Using a nonce as a challenge is a different requirement than a random challenge, because a nonce is not necessarily unpredictable.
A value used in security protocols that is never repeated with the same key. For example, nonces used as challenges in challenge- response authentication protocols generally must not be repeated until authentication keys are changed.
Otherwise, there is a possibility of a replay attack. Using a nonce as a challenge is a different requirement than a random challenge, because a nonce is not necessarily unpredictable.
