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Security and privacy of information transmitted among the devices involved in an Internet of Things (IoT) network represent relevant issues in IoT contexts. Guaranteeing effective control and supervising access permissions to IoT applications is a complex task, mainly due to resources' heterogeneity and scalability requirements. The design and development of highly customizable access control policies, along with an efficient mechanism for ensuring that the rules applied by the IoT platform are not tampered with or violated, will undoubtedly have a significant impact on the diffusion of IoT‐based solutions. In such a direction, the article proposes the integration of a permissioned blockchain within an honest‐but‐curious (i.e., not trusted) IoT distributed middleware layer, which aims to guarantee the correct management of access to resources by the interested parties. The result is a robust and lightweight system, able to manage the data produced by IoT devices, support relevant security features, such as integrity and confidentiality, and resist different kinds of attacks. The use of blockchain will ensure the tamper‐resistance and synchronization of the distributed system, where various stakeholders own applications and IoT platforms. The methodology and the proposed architecture are validated employing a test‐bed. [ABSTRACT FROM AUTHOR]

In the digital age, where the Internet connects things across the globe and individuals are constantly online, data security and privacy are becoming key drivers (and barriers) of change for adoption of innovative solutions. Traditional approaches, whereby communication links are secured by means of encryption, and access control is run in a static way by a centralized authority, are showing their limits when applied to massive-scale, interconnected and distributed systems. Regulations, while still fragmented, are moving to adapt to changes in technology and society, with the aim to protect confidential information by governments, businesses, and individual citizens. In this landscape, proper mechanisms should be defined to allow a strict control over the data life-cycle and to guarantee the privacy and the application of specific regulations on personal information's disclosure, usage and access. Sticky policies represent one approach to improve owners’ control over their data. In such an approach, machine-readable policies are attached to data. They are called 'sticky’ in that they travel together with data, as data travels across multiple administrative domains. In this article we survey the state-of-the-art in sticky policies, discussing limitations, open issues, applications and research challenges, with a specific focus on their applicability to Internet of Things, cloud computing, and Content Centric Networking. [ABSTRACT FROM AUTHOR]

Summary: Fog computing is an emerging paradigm in the Internet of Things (IoT) space, consisting of a middle computation layer, sitting between IoT devices and Cloud servers. Fog computing provides additional computing, storage, and networking resources in close proximity to where data is being generated and/or consumed. As the Fog layer has direct access to data streams generated by IoT devices and responses/commands sent from the Cloud, it is in a critical position in terms of security of the entire IoT system. Currently, there is no specific tool or methodology for analysing the security of Fog computing systems in a comprehensive way. Generic security evaluation procedures applicable to most information technology products are time consuming, costly, and badly suited to the Fog context. In this article, we introduce a methodology for evaluating the security of Fog computing systems in a systematic way. We also apply our methodology to a generic Fog computing system, showcasing how it can be purposefully used by security analysts and system designers. [ABSTRACT FROM AUTHOR]

Optimal stochastic control of delay tolerant networks is studied in this paper. First, the structure of optimal two-hop forwarding policies is derived. In order to be implemented, such policies require knowledge of certain global system parameters such as the number of mobiles or the rate of contacts between mobiles. But, such parameters could be unknown at system design time or may even change over time. In order to address this problem, adaptive policies are designed that combine estimation and control: based on stochastic approximation techniques, such policies are proved to achieve optimal performance in spite of lack of global information. Furthermore, the paper studies interactions that may occur in the presence of several DTNs which compete for the access to a gateway node. The latter problem is formulated as a cost-coupled stochastic game and a unique Nash equilibrium is found. Such equilibrium corresponds to the system configuration in which each DTN adopts the optimal forwarding policy determined for the single network problem. [ABSTRACT FROM AUTHOR]

Internet of Things (IoT) is characterized, at the system level, by high diversity with respect to enabling technologies and supported services. IoT also assumes to deal with a huge amount of heterogeneous data generated by devices, transmitted by the underpinning infrastructure and processed to support value-added services. In order to provide users with valuable output, the IoT architecture should guarantee the suitability and trustworthiness of the processed data. This is a major requirement of such systems in order to guarantee robustness and reliability at the service level. In this paper, we introduce a novel IoT architecture able to support security, privacy and data quality guarantees, thereby effectively boosting the diffusion of IoT services. [ABSTRACT FROM AUTHOR]

Worldwide, societies are seeing rapid change in modes of social interaction and organization. These new interaction modes are predicated on emerging forms of information infrastructure together with rapidly evolving devices, systems, and applications that are ever more deeply interwoven with our social fabric [1]. [ABSTRACT FROM PUBLISHER]

Several novel metrics have been proposed in recent literature in order to study the relative importance of nodes in complex networks. Among those, k-coreness has found a number of applications in areas as diverse as sociology, proteinomics, graph visualization, and distributed system analysis and design. This paper proposes new distributed algorithms for the computation of the k-coreness of a network, a process also known as k-core decomposition. This technique 1) allows the decomposition, over a set of connected machines, of very large graphs, when size does not allow storing and processing them on a single host, and 2) enables the runtime computation of k-cores in “live” distributed systems. Lower bounds on the algorithms complexity are given, and an exhaustive experimental analysis on real-world data sets is provided. [ABSTRACT FROM AUTHOR]

Chemical reaction-diffusion is a basic component of morphogenesis, and can be used to obtain interesting and unconventional self-organizing algorithms for swarms of autonomous agents, using natural or artificial chemistries. However, the performance of these algorithms in the face of disruptions has not been sufficiently studied. In this paper we evaluate the use of reaction-diffusion for the morphogenetic engineering of distributed coordination algorithms, in particular, cluster head election in a distributed computer system. We consider variants of reaction-diffusion systems around the activator-inhibitor model, able to produce spot patterns. We evaluate the robustness of these models against the deletion of activator peaks that signal the location of cluster heads, and the destruction of large patches of chemicals. Three models are selected for evaluation: the Gierer-Meinhardt Activator-Inhibitor model, the Activator-Substrate Depleted model, and the Gray-Scott model. Our results reveal a trade-off between these models. The Gierer-Meinhardt model is more stable, with rare failures, but is slower to recover from disruptions. The Gray-Scott model is able to recover more quickly, at the expense of more frequent failures. The Activator-Substrate model lies somewhere in the middle. [ABSTRACT FROM AUTHOR]

The technology world is experiencing the emergence of a generation of massive-scale networked digital systems, performing complex operations that are partially out of the control of the systems' designers. This is the case, e.g., of pervasive computing environments, characterized by the proliferation of embedded electronic devices with communication and computing capabilities, able to network themselves forming a "digital halo" surrounding the user in its daily activities. In this paper, we advocate the use of bottom-up design patterns, able to build on results in complex systems science and systems biology, for devising new solutions for designing and managing such environments. We also present a possible application to a novel cyberphysical ecosystem, that we call the Energy Web, arising from the combination of innovative information and communication technologies with distributed renewable energy sources. [ABSTRACT FROM AUTHOR]

Delay-tolerant networks, consisting of a number of intermittently connected wireless devices, are emerging as a promising application field, able to complement in some situations infrastructure-based service delivery. In this work, we propose a marked point process model for characterizing the pattern of contacts among nodes in such systems. The model can be used for deriving analytical results on various performance indexes. Validation of the model is performed through comparison with experimental traces obtained from real-world DTN deployments. [ABSTRACT FROM AUTHOR]

Wireless Mesh Networks represent an interesting instance of light-infrastructure wireless networks. Due to their flexibility and resiliency to network failures, wireless mesh networks are particularly suitable for incremental and rapid deployments of wireless access networks in both metropolitan and rural areas. This paper illustrates the design and development of an open toolkit aimed at supporting the design of different solutions for wireless mesh networking by enabling real evaluation, validation, and demonstration. The resulting testbed is based on off-the-shelf hardware components and open-source software and is focused on IEEE 802.11 commodity devices. The software toolkit is based on an "open" philosophy and aims at providing the scientific community with a tool for effective and reproducible performance analysis of WMNs. The paper describes the architecture of the toolkit, and its core functionalities, as well as its potential evolutions. [ABSTRACT FROM AUTHOR]

The quest for the autonomic management of communication systems dates back to more than two decades ago. In practice, it became a compelling need when such systems started growing in size and complexity. The risk, in fact, was that the support/management of the infrastructure became so expensive to be the major design constraint. In telecommunication networks, in particular, autonomicity is perceived practically as an alias of Autonomic Network Management (ANM) [I]: proper handling of network complexity, in fact, is perceived as a cornerstone for achieving robustness and performance. But, despite the expectations, while ANM is emerging as one of the hottest research topics, little concrete results have been achieved so far. This can be ascribed, on one hand, to the complexity of the issue itself, whose theoretical foundations have not been completed so far, and on the other one to the lack of a research platform on which novel solutions can be tested in a controlled and replicable fashion. In such a scenario, due to their reconfigurability and ease of deployment, wireless mesh networks provide us the opportunity to design from scratch an autonomic control plane on top of a network of practical interest. In this paper we propose a novel Knowledge Plane, tailored specifically for the WMNs scenario and capable of enabling consistent sharing of services ontology among the entities participating the WMNs. As a case study, we present JANUS, a novel and freely available monitoring framework exploiting the proposed Knowledge Plane. [ABSTRACT FROM AUTHOR]

Wireless mesh networks are currently emerging as a promising technology for broadband ubiquitous networking. Typical applications range from home broadband Internet access and community networking to wireless metropolitan area networks. Many companies are currently active in this field with proprietary solutions mostly based on the IEEE 802.11 family of standards. At the same time, there are considerable efforts in academia aiming to provide real-world prototypes and testbeds based on open source software and off-the-shelf technologies. This article provides a survey on the most relevant hardware and software platforms that can be used to build a WMN testbed. [ABSTRACT FROM AUTHOR]

We study a fixed-point formalization of the well-known analysis of Bianchi. We provide a significant simplification and generalization of the analysis. In this more general framework, the fixed-point solution and performance measures resulting from it are studied. Uniqueness of the fixed point is established. Simple and general throughput formulas are provided. It is shown that the throughput of any flow will be hounded by the one with the smallest transmission rate. The aggregate throughput is bounded by the reciprocal of the harmonic mean of the transmission rates. In an asymptotic regime with a large number of nodes, explicit formulas for the collision probability, the aggregate attempt rate, and the aggregate throughput are provided. The results from the analysis are compared with ns2 simulations and also with an exact Markov model of the backoff process. It is shown how the saturated network analysis can be used to obtain TCP transfer throughputs in some cases. [ABSTRACT FROM AUTHOR]