Security Schemes for the OLSR Protocol for Ad Hoc Networks. (Schémas de sécurité pour le protocole OLSR pour les réseaux ad hoc)

Within the domain of wireless computer networks, this thesis examines the security issues related to protection of packet routing in ad hoc networks (MANETs). This thesis classifies the different possible attacks and examines in detail the case of OLSR (Optimized Link State Routing protocol). We propose a security architecture based on adding a digital signature, as well as more advanced techniques such as: reuse of previous topology information to validate the actual link state, cross-check of advertised routing control data with the node's geographical position, and intra-network misbehavior detection and elimination via flow coherence control or passive listening. Countermeasures in case of compromised routers are also presented. This thesis also assesses the practical problems concerning the choice of a suitable symmetric or asymmetric cipher, the alternatives for the algorithm of cryptographic keys distribution, and the selection of a method for signature timestamping.