Cryptocurrencies, particularly Bitcoin, continue to be the most prevalent use case within the blockchain ecosystem. One of the inherent limitations of blockchain is that it can create a false sense of privacy. All transaction history and the amount of cryptocurrency held are publicly available, and this information can be easily associated with specific individuals. Many works have proposed fully-private solutions, which are ideal but not realistic in many scenarios. This paper proposes a technical solution that enables private Bitcoin payments by default, but with the option to conditionally disclose payment data. To do so, this solution relies on unlinkability by a decentralized mixer, which can be reversed by a conditional discloser using a trapdoor unlinkability function. The conditional discloser, which also provides accountability of requests, obeys the payer's policies regarding who can access payment data. To ensure compliance, we propose a mixer that does not learn anything about the payment link, but is guaranteed by Zero-Knowledge Proofs that the payment can be relinked by a specific conditional discloser. Furthermore, we provide a proof-of-concept implementation of the proofs, using Circom and SnarkJS. We also present a benchmark that demonstrates the feasibility of this solution. It incurs only one additional parameter per on-chain transaction, while the remainder of the verification data is managed off-chain.

• Adaptable cybersecurity capabilities driven by an adaptive digital twin • Adaptive digital twin for protection, deception, and testing • Characterization of an adaptive digital twin, capable of providing cybersecurity capabilities, such as protection, deception, and testing, in a safe and reliable manner. A Digital Twin (DT) is a cutting-edge technology that has gained relevance in recent years, demonstrating huge potential for the simulation of processes and the provision of valuable insights to improve and optimise systems. Leveraging a high degree of fidelity in replicating real-world processes, DTs are being explored for advanced applications such as deception and proactive protection of critical infrastructures. However, this same advantage also raises concerns with respect to a system’s exposure, as the detailed digital representation may introduce new cybersecurity risks. With the aim of assisting the growth of this technology, this paper presents an adaptive DT solution that facilitates the configuration of particular components of the digital system, tailoring different application scenarios specifically for protection, deception, and testing purposes. Finally, the proposed architecture is tested under a specific IoT-oriented use case to validate, experiment, and extract conclusions of the proposed solution.

The ever-increasing number of cyber-attacks poses a serious challenge to incident response teams. Recent cyber-attacks, such as the attack against energy distribution companies in Ukraine, highlight the disruption which can be caused and its consequences. More than 53 % of recorded incidents targeted essential entities, which heavily rely in Industrial Internet of Things (IIoT) devices, according to ENISA. Despite the amount of work in Cyber Threat Intelligence (CTI) and Intrusion Detection Systems (IDSs), automated response systems have been avoided in connected industrial environments mainly due to the criticality of the underlying assets, where a misstep has the potential to result in the disruption of critical processes. This paper therefore presents an Early and Adaptive Automated Intrusion Response Service for industrial environments, named EAIRS, which combines several techniques, including expert systems and reinforcement learning, to classify and mitigate anomalies detected by IDSs. The incidents EAIRS is designed to face range from network to host-based attacks. This paper provides the architecture for the described approach and the evaluation of a proof-of-concept implementation on an experimental testbed.

Outsourced computations are essential for IoT devices, but they can raise privacy issues. Privacy-preserving technologies, such as Secure Multiparty Computation, can be used to delegate computations on private data from multiple devices while disclosing nothing but the output, but they may come at a prohibitive cost. In particular, Secret Sharing-based Secure Multiparty Computation requires the device to establish n independent confidential channels for each shared message, one channel per holder. This work proposes a new approach for IoT devices to secretly share private data with a committee of holders by broadcasting a single ciphertext. A straightforward solution is Homomorphic Encryption with Decryption to Shares from Chillotti et al., 2022, but it requires Fully Homomorphic Encryption and is not dynamic. Additionally, we propose Oblivious Sharing Re-Encryption, which is a new family of protocols that achieve this lightweight private data sharing without requiring Fully Homomorphic Encryption, and which is also more dynamic. We provide a concrete implementation based on NTRU encryption, together with a security proof and performance analysis. The analysis shows that OSRE outperforms the standard setting with n confidential channels when the device sends more than one message.

In the last few years, malware analysis has become increasingly important due to the rise of sophisticated cyberattacks. One of the objectives of this cybersecurity branch is to find similarities between different files or functions used by malware programmers, thus allowing malware detection, classification and even attribution in a timely manner. In this article we survey the state of the art in this area, reviewing the different techniques that can be applied to the field, with the objective of studying similarity, and therefore detecting, classifying and attributing malware samples. We have developed a fuzzy hash capable of characterizing malware by generating an easily comparable and storable signature of its functions. Since our goal is to detect these similarities in huge amounts of data within a reasonable time-frame, the size of the hash must be limited while retaining as much information as possible.

Abstract Trust can be considered as a multidisciplinary concept, which is strongly related to the context and it falls in different fields such as Philosophy, Psychology or Computer Science. Trust is fundamental in every relationship, because without it, an entity will not interact with other entities. This aspect is very important especially in the Internet of Things (IoT), where many entities produced by different vendors and created for different purposes have to interact among them through the internet often under uncertainty. Trust can overcome this uncertainty, creating a strong basis to ease the process of interaction among these entities. We believe that considering trust in the IoT is fundamental, and in order to implement it in any IoT entity, it is fundamental to consider it through the whole System Development Life Cycle. In this paper, we propose an analysis of different works that consider trust for the IoT. We will focus especially on the analysis of frameworks that have been developed in order to include trust in the IoT. We will make a classification of them providing a set of parameters that we believe are fundamental in order to properly consider trust in the IoT. Thus, we will identify important aspects to be taken into consideration when developing frameworks that implement trust in the IoT, finding gaps and proposing possible solutions.

As the number of security and privacy attacks continue to grow around the world, there is an ever increasing need to protect our personal devices. As a matter of fact, more and more manufactures are relying on Trusted Execution Environments (TEEs) to shield their devices. In particular, ARM TrustZone (TZ) is being widely used in numerous embedded devices, especially smartphones, and this technology is the basis for secure solutions both in industry and academia. However, as shown in this paper, TEE is not bullet-proof and it has been successfully attacked numerous times and in very different ways. To raise awareness among potential stakeholders interested in this technology, this paper provides an extensive analysis and categorization of existing vulnerabilities in TEEs and highlights the design flaws that led to them. The presented vulnerabilities, which are not only extracted from existing literature but also from publicly available exploits and databases, are accompanied by some effective countermeasures to reduce the likelihood of new attacks. The paper ends with some appealing challenges and open issues.

Crowd Counting is a very interesting problem aiming at counting people typically based on density averages and/or aerial images. This is very useful to prevent crowd crushes, especially on urban environments with high crowd density, or to count people in public demonstrations. In addition, in the last years, it has become of paramount importance for pandemic management. For those reasons, giving users automatic mechanisms to anticipate high risk situations is essential. In this work, we analyze ID-based Crowd Counting, and propose a real-time Crowd Counting system based on the Ephemeral ID broadcast by contact tracing applications on wearable devices. We also performed some simulations that show the accuracy of our system in different situations.

This article presents an overview and analysis of the key cybersecurity problems, challenges and requirements to be addressed in the future, which we derived through 63 interviews with European stakeholders from security-critical sectors including Open Banking, Supply Chain, Privacy-preserving Identity Management, Security Incident Reporting, Maritime Transport, Medical Data Exchange, and Smart Cities. We show that common problems, challenges and requirements across these sectors exist in relation to building trust, implementing privacy and identity management including secure and useable authentication, building resilient systems, standardisation and certification, achieving security and privacy by design, secure and privacy-compliant data and information sharing, and government regulations. Our results also indicate cybersecurity trends and allow to derive directions for future research and innovation activities that will be of high importance for Europe.

Industry 4.0 technological expansion and the multiple accesses to the diverse Smart Grid domains (power networks, control systems, market, customer premises) entail the need to provide efficient interconnection mechanisms with connection from anywhere, at any time and in anyhow. However, this type of requirement should not only consist in imposing interoperability solutions between entities and domains, but also in searching the way to justify and trace connections (how, when, where, who) for future governance or auditing actions. This paper, therefore, presents a three layer-based interconnection architecture and several interconnection strategies, all of them adapting the traditional policy decision and enforcement approaches together with the blockchain technology to manage reliable and secure connections among entities, processes and critical resources. With this architecture in mind, the paper also analyzes the coupling level of the blockchain technology, and explores which interconnection strategy is more suitable for Smart Grid domains and their control systems.

In industrial Internet of Things (IIoT) scenarios, where a plethora of IoT technologies coexist with consolidated industrial infrastructures, the integration of security mechanisms that provide protection against cyber-security attacks becomes a critical challenge. Due to the stealthy and persistent nature of some of these attacks, such as Advanced Persistent Threats, it is crucial to go beyond traditional intrusion detection systems (IDSs) for the traceability of these attacks. In this sense, opinion dynamics poses a novel approach for the correlation of anomalies, which has been successfully applied to other network security domains. In this article, we aim to analyze its applicability in the IIoT from a technical point of view, by studying its deployment over different IIoT architectures and defining a common framework for the acquisition of data considering the computational constraints involved. The result is a beneficial insight that demonstrates the feasibility of this approach when applied to upcoming IIoT infrastructures.

With the ever-increasing number of smart home devices, the issues related to these environments are also growing. With an ever-growing attack surface, there is no standard way to protect homes and their inhabitants from new threats. The inhabitants are rarely aware of the increased security threats that they are exposed to and how to manage them. To tackle this problem, we propose a solution based on segmented architectures similar to the ones used in industrial systems. In this approach, the smart home is segmented into various levels, which can broadly be categorised into an inner level and external level. The external level is protected by a firewall that checks the communication from/to the Internet to/from the external devices. The internal level is protected by an additional firewall that filters the information and the communications between the external and the internal devices. This segmentation guarantees a trusted environment among the entities of the internal network. In this paper, we propose an adaptive trust model that checks the behaviour of the entities and in case the entities violate trust rules they can be put in quarantine or banned from the network.

Escrowed decryption schemes (EDSs) are public‐key encryption schemes with an escrowed decryption functionality that allows authorities to decrypt encrypted messages under investigation, following a protocol that involves a set of trusted entities called ‘custodians’; only if custodians collaborate, the requesting authority is capable of decrypting encrypted data. This type of cryptosystem represents an interesting trade‐off to privacy versus surveillance dichotomy. In this study, the authors propose two EDSs where they use proxy re‐encryption to build the escrowed decryption capability, so that custodians re‐encrypt ciphertexts, in a distributed way, upon request from an escrow authority, and the re‐encrypted ciphertexts can be opened only by the escrow authority. Their first scheme, called EDS, follows an all‐or‐nothing approach, which means that escrow decryption only works when all custodians collaborate. Their second scheme, called threshold EDS, supports a threshold number of custodians for the escrow decryption operation. They propose definitions of semantic security with respect to the authorities, custodians and external entities, and prove the security of their schemes, under standard pairing‐based hardness assumptions. Finally, they present a theoretical and experimental analysis of the performance of both schemes, which show that they are applicable to real‐world scenarios.

Edge computing paradigms are expected to solve some major problems affecting current application scenarios that rely on cloud computing resources to operate. These novel paradigms will bring computational resources closer to the users and by doing so they will not only reduce network latency and bandwidth utilization but will also introduce some attractive context-awareness features to these systems. In this paper we show how the enticing features introduced by edge computing paradigms can be exploited to improve security and privacy in the critical scenario of vehicular networks (VNs), especially existing authentication and revocation issues. In particular, we analyze the security challenges in VN and describe three deployment models for vehicular edge computing, which refrain from using vehicular-to-vehicular communications. The result is that the burden imposed to vehicles is considerably reduced without sacrificing the security or functional features expected in vehicular scenarios.

The Internet of Things (IoT) and edge computing are starting to go hand in hand. By providing cloud services close to end-users, edge paradigms enhance the functionality of IoT deployments, and facilitate the creation of novel services such as augmented systems. Furthermore, the very nature of these paradigms also enables the creation of a proactive defense architecture, an immune system, which allows authorized immune cells (e.g., virtual machines) to traverse edge nodes and analyze the security and consistency of the underlying IoT infrastructure. In this paper, we analyze the requirements for the development of an immune system for the IoT, and propose a security architecture that satisfies these requirements. We also describe how such a system can be instantiated in edge computing infrastructures using existing technologies. Finally, we explore the potential application of immune systems to other scenarios and purposes.

The smart grid offers many benefits due to the bidirectional communication between the users and the utility company, which makes it possible to perform a fine-grain consumption metering. This can be used for demand response purposes with the generation and delivery of electricity in real time. It is essential to rapidly anticipate high peaks of demand or potential attacks, so as to avoid power outages and denial of service, while effectively supplying consumption areas. In this paper, we propose a novel architecture where cloud computing resources are leveraged (and tested in practice) to enable, on the one hand, the consumption prediction through time-series forecasting, as well as load balancing to uniformly distribute the demand over a set of available generators. On the other hand, it also allows the detection of connectivity losses and intrusions within the control network by using controllability concepts.

The widespread diffusion of the Internet of Things (IoT) is introducing a huge number of Internet-connected devices in our daily life. Mainly, wearable devices are going to have a large impact on our lifestyle, especially in a healthcare scenario. In this framework, it is fundamental to secure exchanged information between these devices. Among other factors, it is important to take into account the link between a wearable device and a smart unit (e.g., smartphone). This connection is generally obtained via specific wireless protocols such as Bluetooth Low Energy (BLE): the main topic of this work is to analyse the security of this communication link. In this paper we expose, via an experimental campaign, a methodology to perform a vulnerability assessment (VA) on wearable devices communicating with a smartphone. In this way, we identify several security issues in a set of commercial wearable devices.

Abstract Several generic methods exist for achieving chosen‐ciphertext attack (CCA)‐secure public‐key encryption schemes from weakly secure cryptosystems, such as the Fujisaki–Okamoto and REACT transformations. In the context of proxy re‐encryption (PRE), it would be desirable to count on analogous constructions that allow PRE schemes to achieve better security notions. In this paper, we study the adaptation of these transformations to proxy re‐encryption and find both negative and positive results. On the one hand, we show why it is not possible to directly integrate these transformations with weakly secure PRE schemes because of general obstacles coming from both the constructions themselves and the security models, and we identify 12 PRE schemes that exhibit these problems. On the other hand, we propose an extension of the Fujisaki–Okamoto transformation for PRE, which achieves a weak form of CCA security in the random oracle model, and we describe the sufficient conditions for applying it. Copyright © 2016 John Wiley & Sons, Ltd.

The use of alternative foundations for constructing more secure and efficient cryptographic schemes is a topic worth exploring. In the case of proxy re-encryption, the vast majority of schemes are based on number theoretic problems such as the discrete logarithm. In this paper we present NTRUReEncrypt, a new bidirectional and multihop proxy re-encryption scheme based on NTRU, a widely known lattice-based cryptosystem. We provide two versions of our scheme: the first one is based on the conventional NTRU encryption scheme and, although it lacks a security proof, remains as efficient as its predecessor; the second one is based on a variant of NTRU proposed by Stehlé and Steinfeld, which is proven CPA-secure under the hardness of the Ring-LWE problem. To the best of our knowledge, our proposals are the first proxy re-encryption schemes to be based on the NTRU primitive. In addition, we provide experimental results to show the efficiency of our proposal, as well as a comparison with previous proxy re-encryption schemes, which confirms that our first scheme outperforms the rest by an order of magnitude.

Proxy Re-Encryption (PRE) is a type of Public-Key Encryption (PKE) that provides an additional re-encryption functionality. Although PRE is inherently more complex than PKE, attack models for PRE have not been developed further than those inherited from PKE. In this paper we address this gap and define a parametric family of attack models for PRE, based on the availability of both the decryption and re-encryption oracles during the security game. This family enables the definition of a set of intermediate security notions for PRE that ranges from "plain" IND-CPA to "full" IND-CCA. We analyze some relations among these notions of security, and in particular, the separations that arise when the re-encryption oracle leaks re-encryption keys. In addition, we discuss which of these security notions represent meaningful adversarial models for PRE. Finally, we provide an example of a recent "CCA1-secure" scheme from PKC 2014 whose security model does not capture chosen-cipher text attacks through re-encryption and for which we describe an attack under a more realistic security notion. This attack emphasizes the fact that PRE schemes that leak re-encryption keys cannot achieve strong security notions.

Among Big Data technologies, Hadoop stands out for its capacity to store and process large-scale datasets. However, although Hadoop was not designed with security in mind, it is widely used by plenty of organizations, some of which have strong data protection requirements. Traditional access control solutions are not enough, and cryptographic solutions must be put in place to protect sensitive information. In this paper, we describe a cryptographically-enforced access control system for Hadoop, based on proxy re-encryption. Our proposed solution fits in well with the outsourcing of Big Data processing to the cloud, since information can be stored in encrypted form in external servers in the cloud and processed only if access has been delegated. Experimental results show that the overhead produced by our solution is manageable, which makes it suitable for some applications.

Heterogeneity of future networks requires the use of extensible models to understand the Security and QoS tradeoff. We believe that a good starting point is to analyze the Security and QoS tradeoff from a parametric point of view and, for this reason, in a previous paper, we defined the Parametric Relationship Model (PRM) to define relationships between Security and QoS parameters. In this paper, we extend that approach in order to change the behaviour of the model so that different contexts in the same system are considered; that is, to provide a Context-based Parametric Relationship Model (CPRM). The final aim is to provide useful tools for system administrators in order to help them deal with Security and QoS tradeoff issues in the configuration of the environment.

ABSTRACT Motivated by the growing convergence of diverse types of networks and the rise of concepts such as future internet (FI), in this paper, we analyze the coexistence of security mechanisms and quality of service (QoS) mechanisms in resource‐constrained networks, that are relevant types of networks within the FI environment. More precisely, we analyze the current state of the research on security and QoS in the integration of wireless sensor networks, mobile ad hoc networks and cellular networks. Furthermore, we propose a taxonomy to identify similarities among these technologies, as well as the requirements for network interconnection. As a result, we define a dependency‐based model for the analysis of security and QoS tradeoff, and also define a high‐level integration architecture for networks in the FI setting. The final goal is to provide a critical point of view that allows to assess whether such an integration of networks can be both secure and efficient. Copyright © 2013 John Wiley & Sons, Ltd.

ABSTRACT A personal network (PN) should enable the collaboration of user's devices and services in a flexible, self‐organizing, and friendly manner. For such purpose, the PN must securely accommodate heterogeneous technologies with uneven computational and communication resources. In particular, personal radio frequency identification (RFID) tags can enable seamless recognition of user's context, provide user authentication, and enable novel services enhancing the quality and quantity of data handled by the PN. However, the highly constrained features of common RFID tags and their passive role in the network highlights the need of an adequate secure communication model with personal tags, which enables their participation as a member of the PN. In this paper, we present our concept of PN, with special emphasis on the role of RFID and sensor networks, and define a secure architecture for PNs including methods for the secure access to context‐aware technologies from both local PN members and the Internet of Things. The PN architecture is designed to support differentiated security mechanisms to maximize the level of security for each type of personal device. Furthermore, we analyze which security solutions available in the literature can be adapted for our architecture, as well as the challenges and security mechanisms still necessary in the secure integration of personal tags. Copyright © 2013 John Wiley & Sons, Ltd.

The inclusion of identity management in the cloud computing landscape represents a new business opportunity for providing what has been called Identity Management as a Service (IDaaS). Nevertheless, IDaaS introduces the same kind of problems regarding privacy and data confidentiality as other cloud services; on top of that, the nature of the outsourced information (users' identity) is critical. Traditionally, cloud services (including IDaaS) rely only on SLAs and security policies to protect the data, but these measures have proven insufficient in some cases; recent research has employed advanced cryptographic mechanisms as an additional safeguard. Apart from this, there are several identity management schemes that could be used for realizing IDaaS systems in the cloud; among them, OpenID has gained crescent popularity because of its open and decentralized nature, which makes it a prime candidate for this task. In this paper we demonstrate how a privacy-preserving IDaaS system can be implemented using OpenID Attribute Exchange and a proxy re-encryption scheme. Our prototype enables an identity provider to serve attributes to other parties without being able to read their values. This proposal constitutes a novel contribution to both privacy and identity management fields. Finally, we discuss the performance and economical viability of our proposal.

Cloud and IT service providers should act as responsible stewards for the data of their customers and users. However, the current absence of accountability frameworks for distributed IT services makes it difficult for users to understand, influence and determine how their service providers honour their obligations. The A4Cloud project will create solutions to support users in deciding and tracking how their data is used by cloud service providers. By combining methods of risk analysis, policy enforcement, monitoring and compliance auditing with tailored IT mechanisms for security, assurance and redress, A4Cloud aims to extend accountability across entire cloud service value chains, covering personal and business sensitive information in the cloud.

This series of Workshops is organized by ERCIM (European Research Consortium in Informatics and Mathematics) Working Group on Security and Trust Management, that was established in 2005 to foster collaborative work on all theoretical and practical aspects of security, trust and privacy in ICT within the European research community and to increase co-operation of the research community with the European industry.The four articles in this Special Issue were selected from the 17 papers that were accepted for presentation at the Workshop, out of 40 submissions.The articles cover representative topics of STM, such as access control, privacy, security and trust policies, or formal methods.The paper "Scalable automated symbolic analysis of administrative role-based access control policies by SMT solving" by Armando and Ranise considers the problem of automatically analysing administrative role based access control (ARBAC) policies.Such analyses are extremely useful to understand the subtle implications of complex combinations of authorizations, and more generally to ensure that ARBAC systems are scalable and can evolve gracefully.Authors isolate a new class of properties (user-role reachability) for ARBAC policies and leverage state-of-the-art SMT solvers to check automatically their validity.Finally, the strength of their approach is demonstrated through extensive experimental evaluation.In their paper "Stateful authorization logic -proof theory and a case study", Garg and Pfenning embark on the proof-theoretical study of logics for stateful authorization policies; that is, policies that depend on externally controlled conditions.They introduce an expressive logic, called BL, for reasoning about stateful authorization policies.The expressiveness of the logic is achieved through the adoption of a modal connective that allows delegation, and through an explicit modeling of time.Thanks to a careful design that crisply separates between the validity of state predicates and BL judgments, the authors provide an elegant treatment of the meta-theory of BL, and prove that it enjoys admissibility of cut, an essential property that entails consistency.The BL logic is empirically validated through a detailed case study of the US authorization policies for accessing to sensitive intelligence information.The paper "Modeling and preventing inferences from sensitive value distributions in data release" by Bezzi, De Capitani di Vimercati, Foresti, Livraga, Samarati and Sassi considers the following setting: assume a database contains many entries, each of which in its own is considered non-sensitive and can be declassified, but some

Abstract Wireless sensors are battery‐powered devices which are highly constrained in terms of computational capabilities, memory and communication bandwidth. While battery life is their main limitation, they require considerable energy to communicate data. Due to this, it turns out that the energy saving of computationally inexpensive primitives (like symmetric key cryptography (SKC)) can be nullified by the bigger amount of data they require to be sent. In this work, we study the energy cost of key agreement protocols between peers in a network using asymmetric key cryptography. Our main concern is to reduce the amount of data to be exchanged, which can be done by using special cryptographic paradigms like identity‐based and self‐certified cryptography. The main news is that an intensive computational primitive for resource‐constrained devices, such as non‐interactive identity‐based authenticated key exchange, performs comparably or even better than traditional authenticated key exchange (AKE) in a variety of scenarios. Moreover, protocols based in this primitive can provide better security properties in real deployments than other simple protocols based on symmetric cryptography. Our findings illustrate to what extent the latest implementation advancements push the efficiency boundaries of public key cryptography (PKC) in wireless sensor networks (WSNs). Copyright © 2010 John Wiley & Sons, Ltd.

Over the last decade, the Cloud Computing paradigm has emerged as a panacea for many problems in traditional IT infrastructures. Much has been said about the potential of Cloud Computing in the context of the Smart Grid, but unfortunately it is still relegated to a second layer when it comes to critical systems. Although the advantages of outsourcing these kinds of applications to the cloud is clear, data confidentiality and operational privacy stand as mayor drawbacks. In this paper, we describe some security mechanisms, and specifically, some cryptographic schemes, that will help in a better integration of Smart Grids and Clouds. We propose the use of Virtual SCADA in the Cloud (VS-Cloud) as a means to improve reliability and efficiency whilst maintaining the same protection level as in traditional SCADA architectures.

The source-location privacy problem in Wireless Sensor Networks has been traditionally tackled by the creation of random routes for every packet transmitted from the source nodes to the base station. These schemes provide a considerable protection level at a high cost in terms of message delivery time and energy consumption. This overhead is due to the fact that the data routing process is done in a blind way, without knowledge about the location of the attacker. In this work, we propose the Context-Aware Location Privacy (CALP) approach, which takes advantage of the ability of sensor nodes to perceive the presence of a mobile adversary in their vicinity in order to transmit data packets in a more energy-efficient and privacy-preserving manner. In particular, we apply the concepts of CALP to the development of a shortest-path CALP routing algorithm. A permissive and a strict version of the protocol are studied for different adversarial models and the proposed schemes are evaluated through simulation experiments in terms of privacy protection and energy consumption. Finally, we present the conclusions of the paper as well as possible extensions of this work.

Abstract Energy distribution systems are becoming increasingly widespread in today's society. One of the elements that are used to monitor and control these systems are SCADA (Supervisory Control and Data Acquisition) systems. In particular, these control systems and their complexities, together with the emerging use of the Internet and wireless technologies, bring new challenges that must be carefully considered. Examples of such challenges are the particular benefits of the integration of those new technologies, and also the effects they may have on the overall SCADA security. The main task of this paper is to provide a framework that shows how the integration of different state‐of‐the‐art technologies in an energy control system, such as wireless sensor networks, mobilead hocnetworks, and the Internet, can bring some interesting benefits, such as status management and anomaly prevention, while maintaining the security of the whole system. Copyright © 2010 John Wiley & Sons, Ltd.

\n\t\t\t\t\tWith decades of progress toward ubiquitous networks and systems, distributed computing systems have played an increasingly important role in the industry and society. However, not many distributed networks and systems are secure and reliable in the sense of defending against different attacks and tolerating failures automatically, thus guaranteeing properties such as performance, and offering security against intentional threats. This special issue focuses on securing distributed networks and systems.\n\t\t\t\t

Extensive work has been done on the protection of wireless sensor networks (WSNs) from the hardware to the application layer. However, only recently, the privacy preservation problem has drawn the attention of the research community because of its challenging nature. This problem is exacerbated in the domain of WSNs owing to the extreme resource limitation of sensor nodes. In this study the authors focus on the location privacy problem in WSNs, which allows an adversary to determine the location of nodes of interest to him. The authors provide a taxonomy of solutions based on the power of the adversary and the main techniques proposed by the various solutions. In addition, the authors describe and analyse the advantages and disadvantages of different approaches. Finally, they discuss some open challenges and future directions of research.

Abstract The wireless sensor networks (WSN) paradigm is especially vulnerable against external and internal attacks. Therefore, it is necessary to develop security mechanisms and protocols to protect them. These mechanisms must become an integral part of the software architecture and network stack of a sensor node. A question that remains is how to achieve this integration. In this paper we check how both academic and industrial solutions tackle this issue, and we present the concept of a transversal layer, where all the different security mechanisms could be contained. This way, all the elements of the architecture can interact with the security mechanisms, and the security mechanisms can have a holistic point of view of the whole architecture. We discuss the advantages of this approach, and also present how the transversal layer concept was applied to a real middleware architecture. Copyright © 2010 John Wiley & Sons, Ltd.

Security and trust are core research issues for the further development of the Information Society and for 10 years have played, and continue to play, an integral part in the European Union’s Framework Programmes (FPs) for R&D. EU-supported collaborative research projects in trust and security bring together multi-partner stakeholders from industry (technology and service providers, system integrators and end-users), academic and research laboratories working in several interdisciplinary research fields. Sometimes, projects include actors from the legal, social and economic sectors. Together their joint efforts permit a better understanding of the conflicts and synergies between security, privacy and free market economics, as well as of the psychology and sociology of trust and security when building and deploying new technologies. The long term goal for funding this research effort is to convert the know-how of the EU in security, privacy and trust into economic advantages. In the period 1998–2002, under FP5, original and ground-breaking scientific & technological (S&T) work took place in ICT Trust and Security. Key S&T developments achieved at that period included significant advances in cryptology, smart cards and biometrics. EU-supported research also permitted the identification of new concepts in fields of work such as privacy, dependability and risk analysis. In the period 2002–2006, under FP6, research efforts in ICT security and trust have been further intensified. As part of the FP6-IST Programme, 37 R&D projects

No abstract available.

Nowadays, critical control systems are a fundamental component contributing to the overall performance of critical infrastructures in our society, most of which belong to the industrial sector. These complex systems include in their design different types of information and communication technology systems, such as wireless (mesh) sensor networks, to carry out control processes in real time. This fact has meant that several communication standards, such as Zigbee PRO, WirelessHART, and ISA100.11a, have been specified to ensure coexistence, reliability, and security in their communications. The main purpose of this paper has been to review these three standards and analyze their security. We have identified a set of threats and potential attacks in their routing protocols, and we consequently provide recommendations and countermeasures to help Industry protect its infrastructures.

Abstract Concurrent access control is an old problem in many fields in Computer Science. It has been solved in many languages and systems, using mechanisms like monitors or priority queues. Nowadays computers implement multi‐core capabilities. This means that they are virtually capable of execution of processes in parallel. This requires new techniques and open new issues in the field of concurrent access control. Moreover, most operating systems are multi‐user; thus, we have to focus on a multi‐processor multi‐user scenario. Trust becomes a paramount aspect when building distributed applications; the same applies on a lower scale in modern computers. We propose the use of a trust graph that keeps record of the trust relationships of the system and helps in deciding on concurrent access requests. The information encoded in the graph will be used both in order to decide on the access requests and to order granted requests in terms of their associated trust level. Copyright © 2009 John Wiley & Sons, Ltd.

The next generation networks are considered one of the most interesting research and application fields in days to come.The current advances in wireless and mobile networking architectures, services, and applications have spurred an unprecedented emergence of various techniques that may be adopted in next generation wireless communications and mobile network environments.It is, therefore, the right time for an issue in our journal which presents a compilation of the recent advances in this field.The Wireless Communications and Mobile Computing (WCMC) Journal continues to grow swiftly, not only in the number of papers being submitted but also in terms of the diverse technical areas it covers.The papers bring much needed expertise from a wide spectrum of areas in which wireless communications, mobile computing, and emerging technologies converge at.We appreciate the contributions of our authors for bringing together different but relevant areas of wireless innovations, and also appreciate the tremendous support from our readers to make our effort a success.This issue called for papers in various aspects of next generation wireless communications and mobile computing/networking.As a result, nine papers have been selected.The papers cover both topical and innovative areas, each of which is highlighted as follows:

Mobile Grid, in relevance to both Grid and Mobile Computing, is a full inheritor of Grid with the additional feature of supporting mobile users and resources in a seamless, transparent, secure and efficient way. Security of these systems, due to their distributed and open nature, receives great interest. A formal approach to security in the software life cycle is essential to protect corporate resources. However, little thought has been given to this aspect of software development. Due to its criticality, security should be integrated as a formal approach in the software life cycle. A methodology of development for secure mobile Grid computing based systems is defined, that is to say, an engineering process that defines the steps to follow so that starting from the necessities to solve, we can design and construct a secure Grid system with support for mobile devices that is able to solve and cover these necessities.

An ldquoout-of-bandrdquo (OoB) channel can be defined as an extra channel, different from the main wireless channel, that has additional security properties. They are specially suitable for protecting spontaneous interactions and exchanging sensitive data between previously unknown devices. Due to the vulnerable nature of wireless sensor networks (WSN), these kind of channels might be useful for protecting certain sensor network operations. In this paper we analyze the applicability of ldquoout-of-bandrdquo channels to wireless sensor networks, and specify why an optical channel should be a good candidate for implementing an extra channel in sensor nodes. Also, we analyze how the existing security threats may affect this type of channel. Finally, the suitability and usability of optical channels for sensor networks is demonstrated by means of a prototype.

is a mature area in wired networks, and has also attracted many attentions in wireless ad hoc networks recently. Nevertheless, there is no previous work reported in the literature about IDS architectures in wireless sensor networks. In this paper, we discuss the general guidelines for applying IDS to static sensor networks, and introduce a novel technique to optimally watch over the communications of the sensors ’ neighborhood on certain scenarios.

Contract signing is a fundamental service in doing business. The Internet has facilitated the electronic commerce, and it is necessary to find appropriate mechanisms for contract signing in the digital world. A number of two-party contract signing protocols have been proposed with various features. Nevertheless, in some applications, a contract may need to be signed by multiple parties. Less research has been done on multi-party contract signing. In this paper, we propose a new synchronous multi-party contract signing protocol that, with n parties, it reaches a lower bound of 3( n − 1) steps in the all-honest case and 4 n − 2 steps in the worst case (i.e., all parties contact the trusted third party). This is so far the most efficient synchronous multi-party contract signing protocol in terms of the number of messages required. We further consider the additional features like timeliness and abuse-freeness in the improved version. These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Purpose As a value‐added service to deliver important data over the internet with guaranteed receipt for each successful delivery, certified email has been discussed for years and a number of research papers appeared in the literature. This paper aims to present two optimized multi‐party certified email protocols. Design/methodology/approach Reviews two existing email protocols and provides a modified version to overcome their security flaws and weaknesses. Extends the two‐party protocol to a multi‐party scenario. Findings Both of the protocols have three major features. A sender could notify multiple recipients of the same information while only those recipients who acknowledged are able to get the information. Both the sender and the recipients can end a protocol run at any time without breach of fairness. The exchange protocols are optimized, each of which has only three steps, and the trusted third party will not be involved unless an exception (e.g. a network failure or a party's misbehavior) occurs. Originality/value Provides a focus on a value‐added service – certified email.

We describe a novel approach to algorithms concretization that extends the current mode of software visualization from computer screens to the real world. The method combines hands-on robotics and traditional algorithm visualization techniques to help diverse learners comprehend the basic idea of the given algorithm. From this point of view the robots interpret an algorithm while their internal program and external appearance determine the role they have in it. This gives us the possibility to bring algorithms into the real physical world where students can even touch the data structures during the execution. In the first version, we have concentrated on a few sorting algorithms as a proof-of-concept. Moreover, we have carried out an evaluation with 13-to-15-year-old students who used the concretization for gaining insight into one sorting algorithm. The preliminary results indicate that the tool can enhance learning. Now, our aim is to build an environment that supports both visualizations and robotics based concretizations of algorithms at the same time.

In order to study the security systems, we have developed a methodology for the application to the analysis of cryptographic protocols of the formal analysis techniques commonly used in communication protocols. In particular, we have extended the design and analysis phases with security properties. Our proposal uses a specification notation based on HMSC/MSC, which can be automatically translated into a generic SDL specification.