We present a novel scheme called Decentralized Attestation Scheme for Device Swarms (DADS) which is to the best of our knowledge the first to accomplish decentralized attestation in device swarms. Device swarms are smart, mobile, and interconnected devices which operate in large numbers, and are likely to be part of emerging applications in Cyber-Physical Systems (CPS) and Industrial Internet of Things (IIoTs). Swarm devices process and exchange safety, privacy and mission-critical information. Thus, it is important to have a good code verification technique that scales to device swarms and establishes trust among collaborating devices. DADS has several advantages over current state-of-the-art swarm attestation techniques: it is de- centralized, has no single point of failure, and can handle changing topologies after nodes are compromised. DADS assures system resilience to node compromise/failure while guaranteeing only devices that execute genuine code remain part of the group. We conduct performance measurements of communication, computation, memory, and energy using the TrustLite embedded systems architecture in OMNeT++ simulation environment. We show that the proposed approach can significantly reduce communication cost and is very efficient in terms of computation, memory and energy requirements. We also analyze security and show that DADS is very effective and robust against various attacks.
Location-based Services (LBSs) provide valuable services, with convenient features for mobile users. However, the location and other information disclosed through each query to the LBS erodes user privacy. This is a concern especially because LBS providers can be honest-but-curious, collecting queries and tracking users whereabouts and infer sensitive user data. This motivated both centralized and decentralized location privacy protection schemes for LBSs: anonymizing and obfuscating LBS queries to not disclose exact information, while still getting useful responses. Decentralized schemes overcome disadvantages of centralized schemes, eliminating anonymizers, and enhancing users control over sensitive information. However, an insecure decentralized system could create serious risks beyond private information leakage. More so, attacking an improperly designed decentralized LBS privacy protection scheme could be an effective and low-cost step to breach user privacy. We address exactly this problem, by proposing security enhancements for mobile data sharing systems. We protect user privacy while preserving accountability of user activities, leveraging pseudonymous authentication with mainstream cryptography. We show our scheme can be deployed with off-the-shelf devices with an experimental result on automotive testbed.