Meaning – The term nonce, refers to a binary value that is not repeatable by a generating program over a long period of time. It can be a counter or a random value.

In cryptography, a nonce is an arbitrary number that can be used just once in a cryptographic communication. It is similar in spirit to a nonce word, hence the name. It is often a random or pseudo-random number issued in an authentication protocol to ensure that old communications cannot be reused in replay attacks. They can also be useful as initialization vectors and in cryptographic hash functions.

A nonce is an arbitrary number used only once in a cryptographic communication, in the spirit of a nonce word.

Example of usage“To ensure that a nonce is used only once, it should be time-variant (including a suitably fine-grained timestamp in its value) or generated with enough random bits to ensure a probabilistically insignificant chance of repeating a previously generated value. Some authors define pseudo-randomness as a requirement for a nonce.”