This paper presents an architecture, based on Distributed Ledger Technologies\n(DLTs) and Decentralized File Storage (DFS) systems, to support the use of\nPersonal Information Management Systems (PIMS). DLT and DFS are used to manage\ndata sensed by mobile users equipped with devices with sensing capability. DLTs\nguarantee the immutability, traceability and verifiability of references to\npersonal data, that are stored in DFS. In fact, the inclusion of data digests\nin the DLT makes it possible to obtain an unalterable reference and a\ntamper-proof log, while remaining compliant with the regulations on personal\ndata, i.e. GDPR. We provide an experimental evaluation on the feasibility of\nthe use of DFS. Three different scenarios have been studied: i) a proprietary\nIPFS approach with a dedicated node interfacing with the data producers, ii) a\npublic IPFS service and iii) Sia Skynet. Results show that through proper\nconfiguration of the system infrastructure, it is viable to build a\ndecentralized Personal Data Storage (PDS).\n
This paper presents an architecture, based on Distributed Ledger Technologies (DLTs) and Decentralized File Storage (DFS) systems, to support the use of Personal Information Management Systems (PIMS). DLT and DFS are used to manage data sensed by mobile users equipped with devices with sensing capability. DLTs guarantee the immutability, traceability and verifiability of references to personal data, that are stored in DFS. In fact, the inclusion of data digests in the DLT makes it possible to obtain an unalterable reference and a tamper-proof log, while remaining compliant with the regulations on personal data, i.e. GDPR. We provide an experimental evaluation on the feasibility of the use of DFS. Three different scenarios have been studied: i) a proprietary IPFS approach with a dedicated node interfacing with the data producers, ii) a public IPFS service and iii) Sia Skynet. Results show that through proper configuration of the system infrastructure, it is viable to build a decentralized Personal Data Storage (PDS).
Dimitris Chatzopoulos, Sujit Gujar, Boi Faltings, Pan Hui
Advances in mobile computing have paved the way for new types of distributed applications that can be executed solely by mobile devices on device-to-device (D2D) ecosystems (e.g., crowdsensing). More sophisticated applications, like cryptocurrencies, need distributed ledgers to function. Distributed ledgers, such as blockchains and directed acyclic graphs (DAGs), employ consensus protocols to add data in the form of blocks. However such protocols are designed for resourceful devices that are interconnected via the Internet. Moreover, existing distributed ledgers are not deployable to D2D ecosystems since their storage needs are continuously increasing. In this work, we introduce Mneme, a DAG-based distributed ledger that can be maintained solely by mobile devices and operates via two consensus protocols: Proof-of-Context (PoC) and Proof-of-Equivalence (PoE). PoC employs users' context to add data on Mneme. PoE is executed periodically to summarize data and produce equivalent blocks that require less storage. We analyze the security of Mneme and justify the ability of PoC and PoE to guarantee the characteristics of distributed ledgers: persistence and liveness. Furthermore, we analyze potential attacks from malicious users and prove that the probability of a successful attack is inversely proportional to the square of the number of mobile users who maintain Mneme.
Alexandros Bampoulidis, A. Bruni, Lukas Helminger, Daniel Kales · 6 authors
Recent work has shown that cell phone mobility data has the unique potential to create accurate models for human mobility and consequently the spread of infected diseases [74]. While prior studies have exclusively relied on a mobile network operator’s subscribers’ aggregated data in modelling disease dynamics, it may be preferable to contemplate aggregated mobility data of infected individuals only. Clearly, naively linking mobile phone data with health records would violate privacy by either allowing to track mobility patterns of infected individuals, leak information on who is infected, or both. This work aims to develop a solution that reports the aggregated mobile phone location data of infected individuals while still maintaining compliance with privacy expectations. To achieve privacy, we use homomorphic encryption, validation techniques derived from zero-knowledge proofs, and differential privacy. Our protocol’s open-source implementation can process eight million subscribers in 70 minutes.
Alexandros Bampoulidis, A. Bruni, Lukas Helminger, Daniel Kales · 6 authors
Recent work has shown that cell phone mobility data has the unique potential\nto create accurate models for human mobility and consequently the spread of\ninfected diseases. While prior studies have exclusively relied on a mobile\nnetwork operator's subscribers' aggregated data in modelling disease dynamics,\nit may be preferable to contemplate aggregated mobility data of infected\nindividuals only. Clearly, naively linking mobile phone data with health\nrecords would violate privacy by either allowing to track mobility patterns of\ninfected individuals, leak information on who is infected, or both. This work\naims to develop a solution that reports the aggregated mobile phone location\ndata of infected individuals while still maintaining compliance with privacy\nexpectations. To achieve privacy, we use homomorphic encryption, validation\ntechniques derived from zero-knowledge proofs, and differential privacy. Our\nprotocol's open-source implementation can process eight million subscribers in\n70 minutes.\n
Flying Ad Hoc networks, (FANETs) in recent years, have actively been used in monitoring landscape, military and mapping terrains. However, with the advent of the emerging concept of smart cities and new business applications, these flying devices and drones have found a new use case in the medical and governance sector. But these networks suffer from the major problem of centralization. Although centralization does provide reliability and efficiency but also poses the threat of a single point of failure. Meanwhile, blockchain widely known for its decentralization is heavily researched and can be utilized in this case to offer a solution to the problem of centralization of FANETs. Therefore, in this paper, we propose a decentralized architecture of flying ad hoc nodes based on blockchain and using Practical byzantine fault tolerance (PBFT) for consensus among nodes. By employing PBFT, the architecture is not only computationally efficient and fast. In addition, we have used a gossip protocol for passing messages among nodes. Lastly, we have simulated the working of our model and the experimental results show that the proposed method works with nearly constant throughput and latency while increasing the network size and approximately constant message overhead with increase transaction for given network size.
Tingting Song, Bo Cui, Ru Li, Jing Liu · 5 authors
Named Data Networking (NDN) is a new clean-slate architecture for the future Internet. Efficient content retrieval is the original intention of NDN design. The content retrieval process driven by content consumers in NDN includes the following challenges, consumers do not know whether the content exists and whether the content producer is reliable. Invalid interest packets could cause the occupation of limited network resources and DoS attack problem. To ensure the authenticity and integrity of the data packets, consumers need to pre-configure the trust schema, which is centralized and prone to the single point of failure problem. Blockchain has widespread attention to build trust in a distributed way, and Ethereum is a programmable blockchain, a decentralized smart contract platform. To lighten the burden of consumers, we proposed a Smart Contract-based Trusted Content Retrieval Mechanism (SCTCRM) for NDN in this paper. The mechanism contains a trustworthy information base for content and producers based on smart contracts, and provides content retrieval and name resolution services for content consumers. The purpose of this mechanism is to improve the efficiency and security of content retrieval process. We described the framework and the workflow of SCTCRM, and used Colored Petri Nets to create a formal mathematical model and analyze the security of the mechanism. Finally, the cost of storage and Gas in smart contracts are evaluated through the prototype deployment. From the results, we can see that the proposed mechanism is security and practicality.
With the rise in popularity of cryptocurrencies, distributed ledger technology is a term that has gained traction. The aim of this study is to review and comparethe distributed ledger technologies blockchain and directed acyclic graph, examining their internal structures as well as some platforms and existing areas of application. An implementation, the goal of which is to illustrate the components of a possible distributed ledger solution and how they might interact, has been made in the form of a smart contract deployed on a simulated distributed ledger network. To give some explanation to the foundations of distributed ledger technology, a brief overview is given on the topics of cryptography, underlying data structures, and the frameworks used in this study. The literature study has been conducted by collecting and reviewing primarily scientific articles on the topic of distributed ledger technologies and consensus algorithms, as well as white papers on selected distributed ledger platforms. The construction has been done using the framework Hyperledger Fabric. The result chapter reviews how the implemented smart contract fulfills the concrete goals. The study is concluded with a discussion regarding how distributed ledgers might possibly be used in thef uture, what might be done to further develop the implemented smart contract and some of the ethical concerns surrounding distributed ledger technology.
Vehicular ad hoc networks (VANET) are also known as intelligent transportation systems. VANET ensures timely and accurate communications between vehicle to vehicle (V2V) and vehicle to infrastructure (V2I) to improve road safety and enhance the efficiency of traffic flow. Due to its open wireless boundary and high mobility, VANET is vulnerable to malicious nodes that could gain access into the network and carry out serious medium access control (MAC) layer threats, such as denial of service (DoS) attacks, data modification attacks, impersonation attacks, Sybil attacks, and replay attacks. This could affect the network security and privacy, causing harm to the information exchange within the network by genuine nodes and increase fatal impacts on the road. Therefore, a novel secure trust-based architecture that utilizes blockchain technology has been proposed to increase security and privacy to mitigate the aforementioned MAC layer attacks. A series of experiment has been conducted using the Veins simulation tool to assess the performance of the proposed solution in the terms of packet delivery ratio (PDR), end-to-end delay, packet loss, transmission overhead, and computational cost.
About 1Bn people around the globe are born and live without identity documents. In addition, displaced people, projected at 1Bn within a generation, often find themselves without worthy identity documentation even if they had any in their country of origin.
Given that centralized, top-down identity-granting solutions are failing a large portion of the world population, a bottom-up, grassroots, decentralized solution that allows every human being to create and own a trustworthy \emph{genuine global identity} is an urgent necessity. Such a bottom-up solution is worthy only if it is resilient to malicious antagonists that create fake and duplicate identities (so called \emph{sybils}). Furthermore, for a solution to be truly grassroots, the people that rely on it for their global identity should also be its sovereign. Hence its governance has to be sybil-resilient as well.
Here, we present a foundation for a decentralized, grassroots, bottom-up, self-sovereign process in which every human being may easily create and own a genuine global identity, realized as a public key. The solution relies on the formation of a Web of Trust among global identities, but does not rely on biometrics, nor does it require to store any personal information on public or even third-party storage, except for the public key itself. The approach is designed for natural realization using distributed ledger/blockchain technology. For the solution to be complete, additional components are needed, including a mechanism that encourages honest behavior and an egalitarian cryptocurrency to fuel the mechanism. These are a subject for future research.
Social networking sites have given users unprecedented opportunities for the generation and dissemination of content. A variety of social networking sites exist for different purposes, to afford users a range of anonymous and non-anonymous options for self-expression, and the ability to be a part of a virtual community. These “affordances” enable users to create and share content; however, the ability to partially or wholly detach user identity from the content has resulted in unique challenges for content access and content attribution. This paper proposes a framework for secure, trustworthy social networking that also creates value for user-generated content by using a blockchain-enhanced framework for social networking. This work explains the application of such a framework for collocated spaces of robots and IoT devices and identifies key challenges that result as a consequence of merging social networking sites and blockchain technology.
Sara Falcone, Yingsheng Zhang, Agnes Cameron, Amira Abdel-Rahman
This paper proposes a blockchain-based mapping protocol for distributed robotic systems running on embedded hardware. This protocol was developed for a robotic system designed to locomote on lattice structures for space applications. A consensus mechanism, Proof of Validity, is introduced to allow the effort of mining blocks to correlate with the desired tasks the robotic system was designed for. These robots communicate using peer-to-peer LoRa radio. Options, trade-offs and considerations for implementing blockchain technology on an embedded system with wireless radio communication are explored and discussed.
Alex Khawalid, Dan Acristinii, Hans van Toor, Eduardo Castelló Ferrer
Swarm Robotics (SR) faces a series of challenges impeding widespread adoption for real-world applications. Distributed Ledger Technology (DLT) has shown it can solve a number of these challenges. An experiment was conducted to showcase the resolution of these challenges. A search and rescue mission was simulated using drones coupled with single board computers and several simulated agents. Inter-agent communications were facilitated through DLT in a completely decentralized network. A frontend interface was built to demonstrate the ease with which information can be extracted from the system. This paper shows the feasibility of the application of DLT to SR-related challenges in a practical experiment. For future work, it is proposed to focus on more complex tasks through federated learning or inter-swarm communications, possibly through Cosmos.
While direct allocation of spectrum and evolved medium access protocols provide a base for ubiquitous wireless connectivity, the existing TCP/IP and OSI models were designed for wired networks and do not address open interconnection of air interfaces. Without an interconnection model for the air interface, existing network designs continue to tie wireless medium access to that of the backhaul provider for ownership of access and identity trust, resulting in limitations on functionality and coverage. In this paper, we propose a novel solution to access ownership and identity trust by extending the TCP network standard, under a new model we propose, named TCP-Air which integrates distributed ledger technologies directly at the air interface. Further, we present two use cases of the TCP-Air model, demonstrating applications not feasible under existing permissioned-access network designs.
Ajayi Oluwashina Joseph, Joseph Raffety, Philip Morrow, Lin Zhiwei · 7 authors
The proliferation of the Internet of Things has seen it adopted to practically all aspects of life. There has been an increase in demand for more IoT devices which are manufactured by several companies. This has however left need to address vulnerabilities within and threats to these devices. In many cases, these vulnerabilities arise from manufacturer focus on functionality rather than security. Secure by design IoT devices are rare in the market today. Efforts to address this are being made by the IoT research community, however, more effort is required. Deficiencies of current efforts include accountability of devices and privacy of data generated across the IoT landscape. The aim of this Ph.D. research is to improve the security, privacy, veracity, and trust. The approach developed in this study will be based on non-repudiation of actions among self-organized IoT devices in an IoT Ecosystem by leveraging Distributed Ledger Technology (DLT). A proposed system architecture which relies on the Distributed Ledger Technology and its related features will enable services to be applied to the IoT landscape to achieve aspects of end to end IoT security. The initial progress to date is presented within this manuscript.
In this thesis, we present a private distributed ledger system, DLedger, designed for wireless meshed Named Data Networking (NDN) protocol network. DLedger utilizes lightweight Proof-Of-Authentication as gating control mechanism combining data openness among the system peers with verifiable identity within the system. The lightweight nature of Proof-Of-Authentication makes it friendly for the ledger systems consisting of even the constrained Internet of Things (IoT) devices unlike "muscle show" approaches like Proof-Of-Work, Proof-Of-Space, etc. which are storage or computation intensive and combines data openness with anonymity (or pseudonymity). Moreover, different from the popular blockchain-based ledger systems, DLedger utilizes a Directed Acyclic Graph as a fundamental data structure so that its operations can tolerate network partitions. Built over NDN, DLedger truly leverages from its data-centric nature to facilitate data dissemination in peer-to-peer heterogenous IoT networks. We conclude the thesis by reasoning our design through simulation results and discussing a real-world use case.
Summary Decentralization, in the form of mesh networking and blockchain, two promising technologies, is coming to the telecommunications industry. Mesh networking allows wider low‐cost Internet access with infrastructures built from routers contributed by diverse owners, whereas blockchain enables transparency and accountability for investments, revenue, or other forms of economic compensations from sharing of network traffic, content, and services. Crowdsourcing network coverage, combined with crowdfunding costs, can create economically sustainable yet decentralized Internet access. This means that every participant can invest in resources and pay or be paid for usage to recover the costs of network devices and maintenance. While mesh networks and mesh routing protocols enable self‐organized networks that expand organically, cryptocurrencies and smart contracts enable the economic coordination among network providers and consumers. We explore and evaluate two existing blockchain software stacks, Hyperledger Fabric (HLF) and Ethereum geth with Proof of Authority (PoA) intended as a local lightweight distributed ledger, deployed in a real city‐wide production mesh network and in laboratory network. We quantify the performance and bottlenecks and identify the current limitations and opportunities for improvement to serve locally the needs of wireless mesh networks, without the privacy and economic cost of relying on public blockchains.
This thesis focuses on aspects related to the functioning of the gossip\nnetworks underlying three relatively popular cryptocurrencies: Ethereum, Nano\nand IOTA.\n We look at topics such as automatic discovery of peers when a new node joins\nthe network, bandwidth usage of a node, message passing protocols and storage\nschemas and optimizations for the shared ledger. We believe this is a topic\nthat is often overlooked in works about blockchains and cryptocurrencies.\nVulnerabilities and inefficiencies attain a higher significance than ones in a\nregular open source project because of the rather direct financial implications\nof these projects. Barring Bitcoin, a network that has been around for nearly\n10 years, no other project has substantial documentation for its operational\ndetails other than scattered and sparse pages in the source code repositories.\nAlmost all of the content described here has been extracted by studying the\nsource code of the reference implementations of these projects.\n We evaluate the use of Invertible Bloom Lookup Tables and the Graphene\nprotocol to decrease block propagation times and bandwidth usage of certain\nmessages. We perform realistic simulations that show significant improvements.\nWe provide a complete implementation of Graphene in Geth, Ethereum's main node\nsoftware and test this implementation against the main Ethereum blockchain.\n We also crawled the chosen cryptocurrency networks for publicly visible nodes\nand provide an Autonomous System-level breakdown of these nodes with the end\ngoal of estimating the ease of performing attacks such as BGP hijacks and their\nimpact.\n Code written for implementing Graphene in Geth, performing various\nsimulations and for other miscellaneous tasks has been uploaded to Github at\nhttps://github.com/sunfinite/masters-thesis.\n
The public key infrastructure (PKI) based authentication protocol provides the basic security services for vehicular ad-hoc networks (VANETs). However, trust and privacy are still open issues due to the unique characteristics of vehicles. It is crucial for VANETs to prevent internal vehicles from broadcasting forged messages while simultaneously protecting the privacy of each vehicle against tracking attacks. In this paper, we propose a blockchain-based anonymous reputation system (BARS) to break the linkability between real identities and public keys to preserve privacy. The certificate and revocation transparency is implemented efficiently using two blockchains. We design a trust model to improve the trustworthiness of messages relying on the reputation of the sender based on both direct historical interactions and indirect opinions about the sender. Experiments are conducted to evaluate BARS in terms of security and performance and the results show that BARS is able to establish distributed trust management, while protecting the privacy of vehicles.
One remarkable feature of vehicular ad hoc networks is characterized by an opportunistic communications by means of store-carry-forward message relaying which requires the cooperation of vehicles on the networks. However, we cannot be sure that all vehicles willingly contribute their computing resources to the networks for message forwarding with no rewards for their efforts in real-world scenarios. In addition, unfortunately, there may exist some selfish and greedy node which may not help others but tend to take their own gain. To cope with this challenge, incentive mechanisms are generally considered as the promising solution. In this paper, we design a Bitcoin-based secure and reliable incentive scheme for cooperative vehicular delay tolerant networking services. Bitcoin is the well-known worldwide cryptocurrency and digital payment system whose implementation relies on cryptographic techniques, which makes it possible to develop a practical credit-based incentive scheme on the vehicular networks at a low cost. We also implement Bitcoin transaction scripts to handle our proposed incentive scheme.
Cash-less payment via a variety of credit, debit or prepaid cards is pervasive in our interconnected society, but not so ubiquitous in remote rural regions where network connectivity is intermittent. We proposed a cash-less payment scheme for remote villages based on blockchains that allow maintaining a record of verifiable transactions in a distributed manner. We overcome the limitations of intermittent network connectivity by solely relying on blockchain mining nodes in the village for transaction processing and verification. The bank joins as a peer and monitors node behaviors, rewards miners and processes currency exchanges whenever the connectivity is available. We take advantage of the Ethereum network to develop our solution and demonstrate the feasibility of the proposed system on off-the-shelf computing devices. We emulate a remote village scenario with intermittent network connectivity and show the robustness and reliability of the proposed system.
Bluetooth Low Energy (BLE) has emerged as one of the most promising technologies to enable the Internet-of-Things (IoT) paradigm. In BLE-based IoT applications, e.g., wearables-oriented service applications, the Bluetooth MAC addresses of devices will be swapped for device pairings. The random address technique is adopted to prevent malicious users from tracking the victim's devices with stationary Bluetooth MAC addresses and accordingly the device privacy can be preserved. However, there exists a tradeoff between privacy and security in the random address technique. That is, when device pairing is launched and one device cannot actually identify another one with addresses, it provides an opportunity for malicious users to break the system security via impersonation attacks. Hence, using random addresses may lead to higher security risks. In this study, we point out the potential risk of using random address technique and then present critical security requirements for BLE-based IoT applications. To fulfill the claimed requirements, we present a privacy-aware mechanism, which is based on elliptic curve cryptography, for secure communication and access-control among BLE-based IoT objects. Moreover, to ensure the security of smartphone application associated with BLE-based IoT objects, we construct a Smart Contract-based Investigation Report Management framework (SCIRM) which enables smartphone application users to obtain security inspection reports of BLE-based applications of interest with smart contracts.
Dimitris Chatzopoulos, Sujit Gujar, Boi Faltings, Pan Hui
The popularity of digital currencies, especially cryptocurrencies, has been continuously growing since the appearance of Bitcoin. Bitcoin is a peer-to-peer (P2P) cryptocurrency protocol enabling transactions between individuals without the need of a trusted authority. Its network is formed from resources contributed by individuals known as miners. Users of Bitcoin currency create transactions that are stored in a specialised data structure called a block chain. Bitcoin's security lies in a proof-of-work scheme, which requires high computational resources at the miners. These miners have to be synchronised with any update in the network, which produces high data traffic rates. Despite advances in mobile technology, no cryptocurrencies have been proposed for mobile devices. This is largely due to the lower processing capabilities of mobile devices when compared with conventional computers and the poorer Internet connectivity to that of the wired networking. In this work, we propose LocalCoin, an alternative cryptocurrency that requires minimal computational resources, produces low data traffic and works with off-the-shelf mobile devices. LocalCoin replaces the computational hardness that is at the root of Bitcoin's security with the social hardness of ensuring that all witnesses to a transaction are colluders. It is based on opportunistic networking rather than relying on infrastructure and incorporates characteristics of mobile networks such as users' locations and their coverage radius in order to employ an alternative proof-of-work scheme. Localcoin features (i) a lightweight proof-of-work scheme and (ii) a distributed block chain.