A Dynamic Timestamp Discrepancy against Replay Attacks in MANET

Mobile Ad hoc NETworks (MANETs), like traditional networks, are vulnerable to a wide range of Denial-of-Service (DoS) attacks. A Replay attack is one of them that degrade severely the MANET performance. A replay attacker performs this attack by interception and retransmission of the valid signed messages. The validation of signed messages is verified by a timestamp discrepancy fixed by sender and receiver nodes. In this paper, we propose an enhancement of the timestamp concept, to avoid replay attack, characterized by two properties. The first is dynamic because it depends on the communication duration between sender and receiver nodes. The second is rigid because it estimates approximately the maximum date when the signed message should arrive to receive node.