hybrid cellular ad-hoc networks, security, routing protocols While wireless networking seems to be the way of the future, no definite architecture for large scale deployment of such networks has emerged. This can be attributed to financial reasons (a specialized infrastructure is too expensive to build) as well as to the lack of solutions that could work with an existing infrastructure or, in an ad hoc manner, without one. A viable alternative seems to be hybrid wireless networks. Such networks use the existing cellular telephony infrastructure as basis and enhance it by building ad hoc networks of traffic relayers around each cell, improving the overall throughtput and reliability of the network. These relayers are users of the network that are willing to operate as such. In this setting, both efficiency and security are vital properties. We propose SCP as an integrated solution for secure routing and crediting in hybrid networks. We describe how a secure environment can be established efficiently by financially motivating users to avoid attacks. Finally, we show that SCP imposes minimal load both in communication and computation, so that even regular cellular phones can function as relayers, without demanding infrastructure upgrades.