Search

Building trust relationships between different decentralized entities in the IoT ecosystem is essential. Hereof, the combination of blockchain technology and trust evaluation techniques is recently considered as an efficient measure. However, both technologies within the IoT are still facing some limitations which are addressed in this research. First, this publication reviews various blockchain-based trust approaches and depicts their strengths and limitations regarding their usage in decentralized IoT communities. Then, an optimized trust model with a multi-layer adaptive and trust-based weighting system is proposed. Additionally, different trust metric parameters and their mathematical models used for trust evaluation are presented. Moreover, this publication presents a novel approach for incentivization processes in the IoT marketplace using control loops and smart contracts. Thereby, participants are motivated to continuously improve their behavior. Finally, the proposed trust model is proved to be reliable. The experimental results conducted from different scenarios show that the presented approach provides more resiliency against various attacks than existing ones.

The Wireless mesh network (WMN) is a popular network architecture used to support disaster recovery operations. However, few research works have addressed the capacity problem of such a network. This is due to the assumption that the communication network in disaster scenario is built to support services with a low rate requirement like delay tolerant messages. At the same time, the demand for higher data rates has increased in recent years due to the digitalisation of rescue operations and the use of new services (e.g. VoIP, drones and robots). Therefore, the capacity of the WMN is becoming a central issue in the design of future WMNs. This paper proposes a Layer 1 cluster-based network to solve the throughput bottleneck in the WMN. The proposed architecture is evaluated by several real world measurements. The obtained results are compared with the theory. The proposed solution shows a throughput improvement compared to a single-radio WMN and a multi-radio WMN using the CoMTaC channel allocation strategy.

A wireless mesh network (WMN)-based disaster network shall provide an emergency communication infrastructure in case of a catastrophe destroyed any existing communication infrastructure. Since the hardware of the disaster network is deployed in an environment affected by the outcome of a catastrophe, events such as aftershocks and/or outbreaking fires are likely to occur and may destroy the hardware of the disaster network. To maintain its provided functionality and thus its usability, the network requires to be resilient to these and other events which are affecting the network infrastructure. To achieve a resilient network, the normal state of the network as well as possible challenges affecting the normal state need to be defined in prior. This scientific work deals with the derivation and definition of the required normal state of the WMN-based disaster network, as well as the definition of possible challenges resulting from environmental-based events. Since each possible challenge is influencing the network infrastructure of the WMN-based disaster network, possible measures for preventing and/or reducing the impact of each challenge are defined. In addition, emergency corrections capable of resolving the influences of an occurring challenge are defined.

There is a high potential of creating new and market-ready services for the Internet of Things (IoT) community by enabling end-users to make their resources inside the end-user environment available to others. Thus, end-user friendly service platforms facilitate the process of designing and configuring new local and cooperative services. However, decentralized networks of end-users acting as service providers enable the risk of uncontrollable behavior and trustless activities. Blockchain technology coupled with smart contracts now gain popular attention by providing benefits of data immutability and process automation in open or closed communities. This research summarizes several blockchain-based IoT approaches, concluding with their benefits and limitations. Besides them it proposes an optimized and decentralized IoT marketplace consisting of end-user friendly IoT service platforms, forced by a synergy of trust, blockchain and smart contract elements. To highlight the benefits of this synergy, two smart contract use cases (based on Ethereum) in the IoT marketplace are presented.

To provide an emergency communication infrastructure for rescue helpers and victims in the event of a disaster, the research project VirtO4WMN proposes to utilise a Wireless Mesh Network (WMN)-based disaster network. The network is constructed from battery-supplied wireless outdoor routers. By integrating the concept of Network Function Virtualisation (NFV), the network and service availability as well as their reliability are improved. For eliminating the single-point-of-failure of a centralised NFV orchestration the functionality of the NFV orchestration shall be distributed among the nodes in the WMN. For providing the best possible solution for a distributed NFV orchestration in a WMN-based disaster network, various requirements the orchestration must meet are defined and presented in this paper. The requirements are directly derived from the requirements of a WMN-based disaster network, which are also defined in this paper.

In this publication a Network Function Virtualization (NFV) resource advertisement and discovery protocol for a distributed NFV orchestration in a Wireless Mesh Network (WMN)-based disaster network is proposed. The protocol enables the management of a dynamic NFV infrastructure by automatically assigning the currently required management entity to the nodes in the WMN-based disaster network and thus provides the basis for a distributed orchestration. The protocol is defined using a set of methods and a state machine. By using different scenarios, the state machine and the message flow of the protocol is described in detail.

Trust evaluation in decentralized M2M communities, where several end-users provide or consume independently M2M application services, enable the identification of trustless nodes and increase the security level of the community. Several trust management systems using different trust evaluation techniques are presented in the application field of M2M. However, most of them do not provide a secure way to store the computed trust values in the community. Moreover, the trust agents participating in the trust evaluation process are not securely identified and could lead to misbehavior among the trust agents resulting in non-reliable trust values. This research identifies several problems regarding decentralized M2M application services and the trust evaluation process. In order to overcome these issues this research proposes a novel approach by integrating blockchain technology in trust evaluation processes. Moreover, this publication presents a concept for using blockchain within the system for decentralized M2M application service provision. Finally, the combination of P2P overlay and blockchain network is introduced in order to verify the integrity of data.

This publication proposes a novel testing framework for the functional verification of decentralised services and applications in Peer-to-Peer (P2P)-connected Machine-to-Machine (M2M) networks. Besides presented challenges and requirements for testing within distributed environments, a concept for deriving and generating test cases based on a Test Description Language (TDL)-based approach is described and mapped to M2M applications.

P2P-based M2M application frameworks have several advantages, such as increased flexibility, efficiency and a lack of single point of failure as compared to centralised approaches. However, there are several security drawbacks which need to be addressed in order to provide the user a secure environment for the provision and usage of M2M applications. This publication presents different security issues inside P2P-based M2M application frameworks and evaluates P2P protocols based on security. In order to avoid different security attacks, the concept of trust and its importance are emphasized. Furthermore, a trust management system with special trust metric parameters is presented which considers the architecture of P2P-based M2M applications. Finally, blockchain principles are integrated for optimising the overall security in the system by improving data storage between peers, avoiding volatility of peers and ensuring correct working M2M applications.

This publication presents a novel concept for securing P2P-based M2M applications using the integration of a trust management system. In addition, this publication presents different security problems inside the P2P-based M2M application (P2P4M2M) framework and evaluates P2P protocols based on security. Furthermore, this paper emphasises the importance of trust for ensuring security. This is done through a novel concept which uses special trust metric parameters for the P2P4M2M framework.

This publication presents a novel concept for autonomous and decentralised M2M application service provision. The functional architecture of the approach is introduced as well as a detailed description of the system structure and process for application creation. Furthermore, this publication describes details about the proposed process for decentralised M2M application service management and formal description of M2M application services.

The increasing number of intelligent Machine-to-Machine Communication (M2M) devices in the end-user domain provide good resources for creating and sharing M2M application services. Therefore, transferring the role of a traditional centralized service provider to decentralized peers (end-users) acting as service providers is very promising. However, the future of decentralized M2M application services which are independently provided or consumed by several end-users in the M2M community depends on trust. Untrustworthy peers trying to deploy malfunctioning services for others mitigate the benefits of decentralized systems. Nowadays, the concept of distributed ledger and blockchain has an increased popularity regarding trustless computing among communities operating without centralized authorities. This research publication provides a comprehensive analysis and approach merging the concepts of M2M application services, trust and distributed ledger technologies. Moreover, this publication presents an optimized Trust Evaluation System which is used to ensure trustworthiness among peers in a M2M community. To improve the Trust Evaluation System the integration of blockchain for data storage is introduced. Additionally, blockchain technology is used to extend the existing trust model of the Trust Evaluation System to enable tamper-proof data and detection of untrustworthy peers. This publication reviews several existing approaches in the academic and industry sector to highlight the limitations of the blockchain regarding the consensus and proposes a novel Trust Consensus Protocol. This research publication also provides a practical evaluation of the proposed protocol.