An Ad Hoc network is a wireless network with no fixed infrastructure in which all nodes participate in the routing. Ad Hoc networks are considered particularly important in situations where the installation of a fixed infrastructure is costly, difficult, impossible or simply unnecessary. Security routing protocol is the subject of much research in the specific field of security in ad hoc networks. In this book, we presented a first in a list of possible attacks the protocol operations and unaltered messages (such as non-replay or retransmission control messages), then a list of attacks by construction or alteration of the control messages. We gave a definition of the wormhole attack on an ad hoc network, and at the end, we examine the various existing proposals in the literature to overcome this attack.