A router is an information technology device included in a given communication network, such as a packet based network, whose function it is, in particular, to provide a junction between the given network and at least one other network, to direct data packets through the given network, and to transmit data packets from the given network to another network.
An attack against a router can bring about a malfunction of the router and various detrimental consequences, such as breakdown of the network, an interruption of service, a disruption to the activities of the users of the network, and substantial cost and negative advertising.
Such attacks often target routers because of their critical role in a network, and they can be of different types, such as a “man in the middle” attack to monitor data traffic within the network, a denial of service attack, or a subversion attack.
In subversion attacks, the attacker can be connected to the router with current user rights or possibly with administrator rights. Such rights authorize the attacker to modify the router's configuration and to control all processes executed in the router.
There are various routing protocols, such as the OSPF (“Open Shortest Path First”), the BGP (“Border Gateway Protocol”), or the RIP (Routing Information Protocol”) protocols to direct data traffic through networks. During a subversion attack, the attacker can modify the process that generates messages of the routing protocol in order to use fake addresses and to direct data packets over bad routing. For example, data packets can be directed towards equipment belonging to the attacker so that the latter can access such data packets in order potentially to be able to modify them. Such bad routing information can be propagated to all routers in the network.
To ensure secure data exchanges between two routers of a network, certain mechanisms authenticate all messages generated by the routing protocol used by the network. This authentication is carried out by means of secret keys that are deployed and memorized in all routers of the network and which can be changed by each router's administrator. Such authentication mechanisms have the following disadvantages:                when an attacker is in possession of a router's administrator rights, he/she can modify the secret keys required for the router's security functions,        an attacker can potentially change the implementation of the routing protocol to modify the content of messages sent or received, and        secret key management is very onerous, to the extent that secret keys are generally never changed.        
There is therefore a need for a packet based network operator to prevent or limit the consequences of an attack against a network router, in which an attacker could direct all or part of data traffic to a corrupted network address.