We consider the problem of detecting clones in wireless mobile ad-hoc networks. We assume that one of the devices of the network has been cloned. Everything, including saved passwords, certificates and secret keys. We propose a solution in networks of mobile devices carried by individuals - composed by nodes that can communicate by short-range technology like bluetooth or Wi-Fi, and links appear and disappear according to social relationships between users. Our idea is to use social physical contacts, securely collected by wireless personal smart phones, as a biometric way to authenticate the owner of the device and detect the clone attack. We introduce two mechanisms: Personal Marks and Community Certificates. Personal Marks is a simple cryptographic protocol that works well when the adversary is an insider, a malicious node in the network that tries to use the stolen credentials in the social community of the original device that has been cloned. Community Certificates works well when the adversary is an outsider, a node that has the goal of using the stolen credentials when interacting with other nodes that are far in the social network from the original device. When combined, these mechanisms provide an excellent protection against this very strong attack. We prove our ideas and solutions with extensive simulations in both simulated and real world scenarios - with mobility traces collected in a real life experiment.
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