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The Internet of Things (IoT) is an emerging technology that aims to extend connectivity to all everyday devices. One of the main challenges that are slowing down its development is how to secure the Device-to-Device communication. Among all the security issues, the Key Management (KM) is one of the most challenging. The difficulty lies in the fact that most of the IoT devices suffer from a lack of resources. Although different protocols were proposed, most of them do not consider the dynamic nature of the IoT. Other solutions rely on a centralized entity to distribute the new keys upon a change in the network. However, this entity becomes a single point of failure and the main target of attacks. We propose a novel blockchain-based decentralized KM protocol. In addition to being resilient, scalable and dynamic, our solution uses the blockchain technology to securely distribute the KM on several entities.

Recent advances in emerging technologies gave birth to new parading of networks calledInternet of Things (IoT). The emergence of such communicating objects has led practitioners to envision networking a large number of sensors for event monitoring, data collection and filtering. Due to the use of wireless technologies, a secure communication is strongly needed to protect valuable information. Secure group communication is one of the most significant requirements for IoT applications. This employs a group rekeying mechanism for a secure and efficient delivery of data. In this paper, we present a new efficient and scalable rekeying protocol for wireless communicating things. This protocol uses $O(log_2 \sqrt[3]n )$ memory complexity, improving significantly the literature works, where n is the network size. Simulation results show that our protocol has better performances than existing works in several criteria.

Recent advances in emerging technologies have given birth to a new type of networks called Internet of Things (IoT). The emergence of IoT has led practitioners to envision networking a large number of sensors for event monitoring, data collection and filtering. Due to the use of wireless technologies, a secure communication is strongly needed to protect valuable information. Secure group communication is one of the most significant requirements for IoT applications. This employs a group rekeying mechanism for a secure and efficient delivery of data. In this paper, we present a new efficient and scalable rekeying protocol for wireless communicating things. This protocol uses O ( log 2 n 3 ) memory complexity, improving significantly the literature works, where n is the network size. Simulation results show that our protocol has better performances than existing works in several criteria.

The Internet of Things (IoT) is a network made up of a large number of devices which are able to automatically communicate to computer systems, people and each other providing various services for the benefit of society. These devices have the particularity of being heterogeneous and so have different capabilities in terms of storage, computing, communication and energy. One of the main challenges facing the IoT is how to secure communication between these heterogeneous devices. Among all the issues, the Group Key Management is one of the most difficult. Although different approaches have been proposed to solve it, very few of them consider the heterogeneous nature of the IoT. We propose then a highly scalable Multi-Group Key Management protocol for IoT that ensures the forward and backward secrecy, efficiently recovers from collusion attacks, guarantees the secure coexistence of several services in a single network and balances the loads between its heterogeneous devices according to their capabilities. The evaluation of our solution shows that it is efficient for large-scale heterogeneous networks even if they contain highly resource-constrained devices.

This paper presents a hierarchical scheme for sensor networks clustering.The solution proposed combines clustering into cliques and clusters.It takes into account the sizes of cliques and clusters for scalability and energy saving purposes.It improves the end-to-end delay compared to existing works. Wireless sensor networks (WSNs) have a wide range of applications in our lifetime. Indeed, WSNs perform a various missions and tasks in odor localization, firefighting, medical service, surveillance and security. In order to accomplish these tasks, the sensors have to perform partitioning protocols to form an organization into clusters and cliques. The hierarchical clustering is the key solution for WSNs to deal with the scalability problems in a network composed of millions of nodes. In this paper, a new hierarchical partitioning scheme is presented, named MCCC. It is cliques and clusters based hierarchical scheme that takes into account the size of cliques and clusters, it also minimizes the number of hops between the cluster head and its nodes. The proposed scheme is motivated by the need to have minimum and maximum size for cliques and clusters. This hierarchical scheme is proposed to respond to the energy and memory constraints for WSNs.

The Internet of Things (IoT) is a network made up of a large number of devices that collaborate to provide various service for the benefit of society. Two communication modes are required to enable a smooth collaboration. A device can send the same message to several other ones participating in the same service. It may also address a specific device in a Peer-to-Peer manner. The first mode of communication is called Group Communication, while we refer to the second as Device-to-Device Communication. One of the main challenges facing the IoT is how to secure these two modes of communication. Among all the security issues, the Key Management is one of the most challenging. This is mainly due to the fact that most of the IoT devices have limited resources in terms of storage, calculation, communication and energy. Although different approaches have been proposed to deal with this problem, each of them presents its own limitations and weaknesses. Moreover, they usually consider either the Group or the Device-to-Device Communication. In this paper, we propose a novel versatile Key Management protocol for the Internet of Things. To the best of our knowledge, this is the first protocol that secures both modes of communication at the same time. We then analyze the security and performance of our solution and compare it to the existing schemes. For Group Communication, we show that our solution ensures the forward and backward secrecy and, unlike most of the existing Group Key Management protocols, guarantees the secure coexistence of several services in the network. With regard to Device-to-Device Communication, we prove that our solution is flexible and provides a good level of resilience and network connectivity compared to the existing Peer-to-Peer Key Management schemes. We finally demonstrate that, by balancing the loads between the heterogeneous devices according to their capabilities, our solution is both efficient and scalable.

The Internet of Things (IoT) is a network that integrates a variety of heterogeneous nodes, such as connected devices (sensors, robots, smart phones…), connected cars, smart homes, etc. These smart objects communicate and collaborate between each other in distributed and dynamic environments that face several security challenges. Trust management is one of the most important challenges in such environments. Existing trust management solutions do not meet the new requirements of IoT such as heterogeneity, mobility and scalability. In this paper, we propose a hierarchical and scalable based blockchain trust management protocol with mobility support in massively distributed IoT systems. In our protocol, mobile smart objects disseminate trust information about service providers to the blockchain. Thus, all the objects will have a global view about each service provider in the architecture which speeds up the trust decision making. In addition, our protocol is resilient against known malicious attacks such as \textit{bad-mouthing}, \textit{ballot-stuffing} and \textit{cooperative attacks}. We confirm the efficiency of our proposal through theoretical analysis and extensive simulations. Finally, we show that it outperforms existing solutions especially in terms of scalability, mobility support, communication and computation.

International audience; Internet of Things (IoT) is a network made up of a large number of devices which are able to automatically communicate to computer systems, people and each other providing various services for the benefit of society. One of the main challenges facing the IoT is how to secure communication between these devices. Among all the issues, the Group Key Management is one of the most difficult. Although different approaches have been proposed to solve it, most of them use the same security parameters to secure all communications. Thus, if several services are provided by the network, communications within a service will be accessible to all network members even those which did not subscribe to it. Moreover, the compromise of a member will jeopardize all services. In this paper, we propose a highly scalable Multi-Group Key Management protocol for IoT which ensures the forward and backward secrecy, efficiently recovers from collusion attacks and guarantees the secure coexistence of several services in a single network. To achieve this, our protocol manages several groups with independent security parameters.

Internet of Every things (IoE) is a network that integrates a variety of heterogeneous nodes, such as connected portable devices, connected cars, smart home appliances, humans, etc. to Internet. The constituents of IoE are heterogeneous, distributed by nature and also autonomous in most of cases, which meet the criteria of what we call Systems of Systems (SoS). These smart objects communicate and collaborate between each other in dynamic environments which are subject to several security attacks. In this paper, we propose a hierarchical based blockchain trust management architecture with mobility support in highly distributed IoE based Systems of Systems. This architecture deals efficiently with scalability issues. It allows smart objects to disseminate the trustworthiness of the service providers they interact with them to the blockchain. This later makes the access to this information possible from anywhere and ensures a global view of trustworthiness information. Thanks to the blockchain technology, our architecture outperforms the existing trust management solutions especially in terms of scalability and mobility support.

MEMS microrobots are miniaturized electro-mechanical elements, made using the techniques of micro-fabrication. They have limited energy capacity and low memory space. Self-reconfiguration is required for MEMS microrobots to complete their mission and/or to optimize their communication. In this paper, we present a self-reconfiguration protocol from a straight chain to square organization, which deals with MEMS microrobots characteristics. In the proposed protocol, nodes do not have the map of their target positions which makes the protocol portable, standalone, and the memory complexity is bounded by a constant. This paper improves a former solution by using parallelism in the movements of microrobots to optimize the time and the number of movements and by making the algorithm energy-aware. So each node is aware of the amount of energy that it will spend, which will improve the energy consumption. Our algorithm is implemented in Meld, a declarative language, and executed in a real environment simulator called DPRSim. We present a parallel and energy-ware protocol for self-reconfiguration of microrobots.From chains configurations to squares configurations.This protocol is efficient and scalable because it is map-less.This protocol needs a constant complexity of memory usage.Evaluation is made with the Dynamic Physical Rendering Simulator.

This paper considers the broadcast/receive communication model in which message collisions and message conflicts can occur because processes share frequency bands. (A collision occurs when, during the same round, messages are sent to the same process by too many neighbors. A conflict occurs when a process and one of its neighbors broadcast during the same round.) More precisely, the paper considers the case where, during a round, a process may either broadcast a message to its neighbors or receive a message from at most m of them. This captures communication-related constraints or a local memory constraint stating that, whatever the number of neighbors of a process, its local memory allows it to receive and store at most m messages during each round. The paper defines first the corresponding generic vertex multi-coloring problem (a vertex can have several colors). It focuses then on tree networks, for which it presents a lower bound on the number of colors K that are necessary (namely, \(K=\lceil \frac{\varDelta }{m}\rceil +1\), where \(\varDelta \) is the maximal degree of the communication graph), and an associated coloring algorithm, which is optimal with respect to K.

The vertex coloring problem has received a lot of attention in the context of synchronous round-based systems where, at each round, a process can send a message to all its neighbors, and receive a message from each of them. Hence, this communication model is particularly suited to point-to-point communication channels. Several vertex coloring algorithms suited to these systems have been proposed. They differ mainly in the number of rounds they require and the number of colors they use. This paper considers a broadcast/receive communication model in which message collisions and message conflicts can occur (a collision occurs when, during the same round, messages are sent to the same process by too many neighbors; a conflict occurs when a process and one of its neighbors broadcast during the same round). This communication model is suited to systems where processes share communication bandwidths. More precisely,the paper considers the case where, during a round, a process may either broadcast a message to its neighbors or receive a message from at most $m$ of them. This captures communication-related constraints or a local memory constraint stating that, whatever the number of neighbors of a process, its local memory allows it to receive and store at most $m$ messages during each round. The paper defines first the corresponding generic vertex multi-coloring problem (a vertex can have several colors). It focuses then on tree networks, for which it presents a lower bound on the number of colors $K$ that are necessary (namely, $K=\lceil\frac{\Delta}{m}\rceil+1$, where $\Delta$ is the maximal degree of the communication graph), and an ssociated coloring algorithm, which is optimal with respect to $K$.

International audience; Modular robots represent a major technological challenges in the last decades because of expectations on their massive use in our lifetime, particularly in order to improve the well-being of people. Indeed, modular robots are gaining increasing attention due to their use in various missions and tasks in a wide range of applications, including location, the fight against fires, medical services, surveillance and security, and search and rescue. They can perform tasks in unstructured environments, complex, dynamic and unknown. To carry out these missions robots must apply reconfiguration protocols to adapt to working conditions. These reconfiguration protocols must deal with the limitations of nodes including those relating to memory and energy resources. Also, these algorithms should be effective, scalable, secure and robust, using only local information. In this paper, we provide a review on the recent protocols that achieve the self-reconfigurations without predefined positions of the target shape.}, keywords={microrobots;MEMS microrobots;energy resources;fire fighting;mapless reconfiguration;medical services;memory resources;modular robots;reconfiguration protocols;search and rescue;security;self-reconfigurations;surveillance;unstructured environments;Heuristic algorithms;Prediction algorithms;Protocols;Robot kinematics;Robustness;Shape;MEMS;Mapless;Modular robots;reconfiguration

International audience; In this paper, we propose an improvement of the logical topology by using a self-reconfiguration protocol in MEMS microrobot networks. Recently, solutions have been given for this problem for a chain of microrobots as a starting physical topology; the advantage of these solutions is that they are distributed protocols without a map of the target shape which makes them efficient and scalable. This paper shows how to generalize the solution for any starting physical topology. We propose an efficient map-less self-reconfiguration protocol where nodes can perform the algorithm regardless of the place where they are deployed, because the algorithm is independent of the map of the target shape. Furthermore, our solution tries to reach the target shape with a minimum amount of movement. The protocol consists of two main algorithms, initiator election and shape shifting. The initiator election aims to choose the best initiator that initializes the algorithm shape shifting, and the criterion of choice is the effect on the amount of movement on the other nodes. The shape shifting algorithm aims to convert the initial physical topology with an incremental process using collaboration, coordination and help between nodes. This protocol is implemented in DPRSim, the Dynamic Physical Rendering Simulator.

International audience; Self-reconfiguration for mobile microrobots currently needs a positioning system and a map of the target shape. Traditional positioning solutions, such as GPS or multilateration are not applicable in the micro-world, and maps sharing does not scale. In the literature, if we want a self-reconfiguration of microrobots to a target shape that consists of millions of positions, each microrobot should have a memory capacity of at least million positions. Therefore, this is not scalable. In this paper, nodes do not record any position. We present self-reconfiguration methods where nodes are unaware of their positions and where they do not have the final coordinates of each microrobot. In other words, nodes do not store the coordinates that build the target shape. Therefore, memory usage for each node is hugely reduced to O(1) and communications are limited to neighboring nodes. These algorithms aim to improve the logical topology of a set of microrobots by restructuring their physical topology. To that end, we consider here the case of restructuring a set of microrobots from a chain to a square and we study two algorithms: the first algorithm ensures the connectivity of the network at the end of the algorithm, where the second guarantees the connectivity of the network through the execution time. The paper presents both analytical and experimental assessments of the algorithms performances using the declarative language Meld and executed under the Dynamic Physical Rendering Simulator (DPRSim).

International audience; MEMS micro robots are low-power and low memory capacity devices that can sense and act. One of the most challenges in MEMS micro robot applications is the self-reconfiguration, especially when the efficiency and the scalability of the algorithm are required. In the literature, if we want a self-reconfiguration of micro robots to a target shape consisting of P positions, each micro robot should have a memory capacity of P positions. Therefore, if P equals to millions, each node should have a memory capacity of millions of positions. Therefore, this is not scalable. In this paper, nodes do not record any position, we present a self-reconfiguration method where a set of micro robots are unaware of their current position and do not have the map of the target shape. In other words, nodes do not store the positions that build the target shape. Consequently, memory usage for each node is reduced to O(1). An algorithm of self-reconfiguration to optimize the communication is deeply studied showing how to manage the dynamicity (wake up and sleep of micro robots) of the network to save energy. Our algorithm is implemented in Meld, a declarative language, and executed in a real environment simulator called DPRSim.

International audience; MEMS microrobots are low-power and low-memory capacity devices that can sense and act. One of the most difficult challenges in MEMS microrobot applications is the selfreconfiguration, especially when the efficiency, parallelism and the scalability of the algorithm are required. Self-reconfiguration with shared map does not scale. Because the map (predefined position of the target shape) consists of P positions, and each node must have a memory capacity, at least, of P positions. Therefore, if P is very high, the self-reconfiguration will be not feasible. In this paper, we present an efficient reconfiguration algorithm, without predefined positions of the target shape, which reduces memory usage to O(1). This algorithm ensures the networks connectivity throughout all its execution time. This solution improves the execution time and the number of movements by using movement of different microrobots at the same time that we call parallelism of movement. Our algorithm is implemented in Meld, a declarative language, and executed in a real environment simulator called DPRSim.

International audience; In this paper we present a dynamic self reconfiguration protocol for MEMS micro robots. The protocol presented in this paper is without map of the target shape which makes it efficient and scalable. In other words, nodes do not store the positions that build the target shape. Consequently, memory usage for each node is reduced to a constant complexity. An algorithm of self-reconfiguration is deeply studied showing how to manage the dynamicity (wake up and sleep of micro robots)of the network to save energy. Our algorithm is implemented in Meld, a declarative language, and executed in a real environment simulator called DPRSim.