Wireless ad hoc networks are networks composed solely of wireless, arbitrary moving nodes. There are no centralized entities like servers or routers, thus all the network functionality must be provided by the nodes themselves. These properties creates problems for several existing protocols, among them routing protocols. There have been developed several routing protocols for use in ad hoc networks, among them are the Optimized Link State Routing (OLSR) protocol. For a network to be secure and reliable a secure routing protocol must be used. In its native form the OLSR protocol does not provide any security at all. To create a more secure OLSR protocol I propose to add a digital signature to the header of the routing packets. This signature, which can be verified by the receiving node, should bring some security into the OLSR protocol. In this master thesis I will discuss and analyze the proposal for a more secure OLSR protocol. I will present an implemented, working prototype for this mechanism, and I will present some initial testing with this prototype. This thesis also provide background information on topics related to the security mechanism proposed.