Nonce

That will do for the nonce, but we'll need a better answer for the long term.

[...] Dunce, / Dotard, a-dozing at the very nonce, / After a life spent training for the sight!

'Idiot!' exclaimed the doctor, who for the nonce was not capable of more than such spasmodic attempts at utterance.

I had thought that the term was a nonce, but it seems as if it's been picked up by other authors.

The information gained by the eavesdropper would permit a replay attack, but only with a request for the same document, and even that may be limited by the server's choice of nonce.

The protocol opens with A communicating in clear to AS his own claimed identity and the identity of the desired correspondent, B, together with A's nonce identifier for this transaction, I_(A1). ("Nonce" means "used only once.")

Both CCM and GCM require a unique nonce (N used once) value to maintain their privacy and authenticity goals.

The main idea with the challenge-response type of authentication protocol is that the challenge sent by the server is used only once (referred to as a cryptographic nonce, which means “number used once”).