Nonce

nouncandidate·updated May 12, 2026

No definition recorded.

Framework senses

NISTIR 7298: Glossary of Key Information Security Terms, Revision 22 sensesview framework →
§1
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.
§2 · sense_2_pending_review
A random or non-repeating value that is included in data exchanged by a protocol, usually for the purpose of guaranteeing the transmittal of live data rather than replayed data, thus detecting and protecting against replay attacks.
CNSSI-4009 (Glossary of Information Assurance Terms)1 senseview framework →
§1
A random or non-repeating value that is included in data exchanged by a protocol, usually for the purpose of guaranteeing the transmittal of live data rather than replayed data, thus detecting and protecting against replay attacks.
NIST SP 800-631 senseview framework →
§1
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.