This paper describes a framework for a Multi-UAV surveillance system based on a blockchain allowing to coordinate the UAVs and to manage financial exchanges between the different users. The objective of the system is to allow a set of Points-Of-Interest (POI) to be surveyed by a set of autonomous UAVs which cooperate to minimize the time between successive visits while having an unpredictable behavior to prevent external agents from learning their movements. The system can be seen as a marketplace where the UAVs are the service providers and the POIs are the service seekers. It is based on a blockchain embedded on the UAVs and on some nodes on the ground which has two main functionalities. The first one is to organize the routes of each UAV through an efficient Game Theoretical decision algorithm implemented in a smart contract. The second one is to allow financial transactions between the system and its users: the POIs subscribe to surveillance services by buying tokens and the UAVs are paid in tokens for the provided services. The first implementation tests show that the IOTA blockchain could be a good blockchain candidate to be integrated in the multi-UAV surveillance system already developed in our lab
