To detect runtime attacks against programs running on a remote computing platform, Control-Flow Attestation (CFA) lets a (trusted) verifier determine the legality of the program's execution path, as recorded and reported by the remote platform (prover). However, besides complicating scalability due to verifier complexity, this assumption regarding the verifier's trustworthiness renders existing CFA schemes prone to privacy breaches and implementation disclosure attacks under "honest-but-curious" adversaries. Thus, to suppress sensitive details from the verifier, we propose to have the prover outsource the verification of the attested execution path to an intermediate worker of which the verifier only learns the result. However, since a worker might be dishonest about the outcome of the verification, we propose a purely cryptographical solution of transforming the verification of the attested execution path into a verifiable computational task that can be reliably outsourced to a worker without relying on any trusted execution environment. Specifically, we propose to express a program-agnostic execution path verification task inside an arithmetic circuit whose correct execution can be verified by untrusted verifiers in zero knowledge.

Privacy-preserving smart meter data collection and analysis are critical for optimizing smart grid environments without compromising privacy. Using homomorphic encryption techniques, smart meters can encrypt collected data to ensure confidentiality, and other untrusted nodes can further compute over the encrypted data without having to recover the underlying plaintext. As an illustrative example, this approach can be useful to compute the monthly electricity consumption without violating consumer privacy by collecting fine-granular data through small increments of time. Toward that end, we propose an architecture for privacy-preserving smart meter data collection, aggregation and analysis based on lattice-based homomorphic encryption. Furthermore, we compare the proposed method with the Paillier and Boneh-Goh-Nissim (BGN) cryptosystems, which are popular alternatives for homomorphic encryption in smart grids. We consider different services with different requirements in terms of multiplicative depth, e.g. billing, variance and nonlinear support vector machine classification. Accordingly, we measure and show the practical overhead of using the proposed homomorphic encryption method in terms of communication traffic (ciphertext size) and latency. Our results show that lattice-based homomorphic encryption is more efficient than Paillier and BGN for both multiplication and addition operations while offering more flexibility in terms of the computation that can be evaluated homomorphically.

Peer-to-peer distributed storage systems can be instrumental to develop solutions able to store the massive amounts of data generated by the Internet of Things (IoT) users. Given the higher probability of node failures, losses in the communication channels, and limited resources of devices compared to centralized storage solutions, it is key to minimize data retrieval time, while also maintaining high resiliency in the system. We propose a method based on random linear network coding (RLNC) for data storage and retrieval and the use of Kademlia for our peer-to-peer design to address these challenges. We analyze the performance of the proposed RLNC-based method theoretically as well as the traditional Kademlia in terms of data retrieval time and resiliency to node failures and channel losses. We use PeerSim to simulate the proposed method. Our theoretical analysis and simulation results show that the proposed RLNC-based method significantly outperforms traditional Kademlia for our core performance metrics. These gains in resiliency and data retrieval time are achieved while also reducing the data storage time for a wide region of operation. Our simulations show that only if the redundancy of the RLNC-based scheme is significantly increased (> 100 % redundant RLNC packets), then a small degradation (< 10 %) in data storage time occurs.

Autonomous Unmanned Aerial Vehicles (UAVs) find increasing use in the civil airspace where multi-UAV systems are deployed to perform operations supervised by remote control facilities.Since these multi-UAV systems operate in public locations and connect using open communication standards, it raises significant security concerns.While most UAV designers befittingly deal with the complexity of autonomy, communication, and control, they often ignore to consider system security aspects in the early design phase.To support the security design process of multi-UAV systems, this paper provides an analysis of cybersecurity threats of multi-UAV systems based on the STRIDE model.The identified threats are subsequently linked with a risk assessment to be prioritized according to severity.We conclude by establishing a set of security design recommendations for connected inspection UAVs to contribute with guidance for the design of future multi-UAV systems.

This paper presents a complete framework for content discovery and retrieval in Information-Centric Networks. For content discovery, we implement a method similar to our previously developed pull-based BFR [1], which uses Bloom filter-based signaling to inform servers about the name prefixes of available requests. For content retrieval, we propose in this paper a feedback-based cooperative protocol implementing network coding-based forwarding. The proposed network coding-based protocol provides a distributed solution to control the multisession codeblock size, i.e., the number of variables that are combined into network coded packets, by setting a capacity constraint on each node and by piggybacking the available capacity as feedback on messages sent to neighbors. The network codes are decided using linear programming. We compare the proposed network coding-based protocol with push-based BFR [2] and pull-based BFR [1]. The results show that the proposed protocol outperforms both push-based BFR and pull-based BFR in terms of content discovery overhead and average content block retrieval delay.

A service-centric network requires a routing protocol to route service requests towards service providers. Routing operations can be divided into intra-domain and inter-domain routing. In the proposed approach, a so-called supernode is responsible for managing its own domain as well as for communicating with the supernodes of other domains to perform inter-domain routing. In order to appoint appropriate nodes as supernodes in the network topology, in this paper, we use Dominating Sets (DS) and Connected Dominating Sets (CDS). We propose fully distributed algorithms for constructing DS as well as CDS over the network topology. To prepare routing information, the nodes of each domain inform their supernodes about their available service names and resources (e.g., CPU, RAM). To this aim, the nodes use Bloom filters which reduce bandwidth and storage overhead. The performance evaluation shows that the required bandwidth overhead for DS and CDS construction algorithms increases with the topology size. The results also show that for large network topologies, CDS-based routing requires significantly less bandwidth overhead than both DS-based routing and Named Data Networking with multicast forwarding strategy. Finally, from the results we can observe that both DS-based and CDS-based routing have significantly lower service retrieval time than NDN multicast strategy.

L-SCN is a two-layered Service-Centric Networking (SCN) architecture. The L-SCN design splits the network into domains and specifies communication protocols for service provider information propagation. Nodes in a domain receive substantial knowledge about the available resources (e.g., CPU, RAM) and available services within the domain, while the communication between different domains is realized through supernodes. We extend L-SCN with new communication mechanisms, which improve the processing time and provide lower protocol overhead for service request processing. The two proposed mechanisms are named event-driven and provider-driven. The event-driven mechanism propagates service provider information based on an event (e.g., high overload). The provider-driven mechanism propagates service provider information periodically.

In Named Data Networking (NDN), there is a need for routing protocols to populate Forwarding Information Base (FIB) tables so that the Interest messages can be forwarded. To populate FIBs, clients and routers require some routing information. One method to obtain this information is that network nodes exchange routing information by each node advertising the available content objects. Bloom Filter-based Routing approaches like BFR [1], use Bloom Filters (BFs) to advertise all provided content objects, which consumes valuable bandwidth and storage resources. This strategy is inefficient as clients request only a small number of the provided content objects and they do not need the content advertisement information for all provided content objects. In this paper, we propose a novel routing algorithm for NDN called pull-based BFR in which servers only advertise the demanded file names. We compare the performance of pull-based BFR with original BFR and with a flooding-assisted routing protocol. Our experimental evaluations show that pull-based BFR outperforms original BFR in terms of communication overhead needed for content advertisements, average roundtrip delay, memory resources needed for storing content advertisements at clients and routers, and the impact of false positive reports on routing. The comparisons also show that pull-based BFR outperforms flooding-assisted routing in terms of average round-trip delay.

Service-Centric Networking (SCN) is a Future Internet architecture extending ICN with support for services, in which addressing and routing centers around services. SCN provides session support, however, recovery mechanisms do not exist in SCN session management. Therefore, SCN sessions suffer from link and node failures. In this paper, we present the design, implementation, and evaluation of three link failure recovery techniques for sessions in SCN. The first mechanism is based upon propagating session identifiers within the network using Bloom filters, the second design is based upon the propagation of service provider identifiers, and the third design uses piggy-backing for the propagation of service provider identifiers.

Bloom filter-based routing protocols for Named Data Networking (NDN) aim at facilitating content discovery in NDN. In this paper, we compare the performance of two Bloom filter-based routing protocols, namely BFR and COBRA. BFR is a push-based routing protocol that works based on Bloom filter-based content advertisements, while COBRA is a pull-based routing protocol that operates based on route traces left from previously retrieved content objects, which are stored in Stable Bloom Filters. In this paper, we show that BFR outperforms COBRA in terms of average memory needed for storing routing updates, average round-trip delay, normalized communication overhead, total Interest communication overhead, and mean hit distance.

Epidemic forwarding has been proposed as a forwarding technique to achieve opportunistic communication in delay tolerant networks (DTNs). Even if this technique is well known and widely referred, one has to address several practical problems before using it. Unfortunately, while the literature on DTNs is full of new techniques, very little has been done in comparing them. In particular, while Bloom filters have been proposed to exchange information about the buffer content prior to sending information in order to avoid redundant retransmissions, up to our knowledge no real evaluation has been provided to study the tradeoffs that exist for using Bloom filters in practice. A second practical issue in DTNs is buffer management (resulting from finite buffers) and congestion control (resulting from greedy sources). This has also been the topic of several papers that had already uncovered the difficulty to acquire accurate information mandatory to regulate the data transmission rates and buffer space. In this paper, we fill this gap. We have been implementing a simulation of different proposed congestion control schemes for epidemic forwarding in ns-3 environment. We use this simulation to compare different proposed schemes and to uncover issues that remain in each one of them. Based on this analysis, we proposed some strategies for Bloom filter management based on windowing and describe implementation tradeoffs. Afterwards, we propose a back-pressure rate control as a well as an aging based buffer managing solution to deal with congestion control. By simulating our proposed mechanisms in ns-3 both with random-waypoint mobility and realistic mobility traces coming from San-Francisco taxicabs, we show that the proposed mechanisms alleviate the challenges of using epidemic forwarding in DTNs.

Epidemic forwarding has been proposed as a forwarding technique to achieve opportunistic communication in Delay Tolerant Networks. Even if this technique is well known and widely referred, one has to first deal with several practical problems before using it. In particular, in order to manage the redundancy and to avoid useless transmissions, it has been proposed to ask nodes to exchange information about the buffer content prior to sending information. While Bloom filter has been proposed to transport the buffer content information, up to our knowledge no real evaluation has been provided to study the tradeoff that exists in practice. In this paper we describe an implementation of an epidemic forwarding scheme using Bloom filters. Then we propose some strategies for Bloom filter management based on windowing and describe implementation tradeoffs. By simulating our proposed strategies in ns-3 both with random waypoint mobility and realistic mobility traces coming from San Francisco taxicabs, we show that our proposed strategies alleviate the challenge of using epidemic forwarding in DTNs.