Replay Attack

cryptography

Definition

Replay Attack

A replay attack is a protocol attack in which the same message is duplicated and sent several times to the intended recipient.

Avoidance

Challenge-Response Nonce Handshake

A solution is to exploit a challenge-response nonce handshake. A nonce is a randomly generated number used in a single protocol session and then discarded. An authentication request is accepted only if no authentication request with the same nonce has previously been accepted.