This work presents ContractChecker, a Blockchain-based security protocol for verifying the storage consistency between the mutually distrusting cloud provider and clients. Unlike existing protocols, the ContractChecker uniquely delegates log auditing to the Blockchain, and has the advantages in reducing client cost and lowering requirements on client availability, lending itself to modern scenarios with mobile and web clients. The ContractChecker collects the logs from both clients and the cloud server, and verifies the consistency by cross-checking the logs. By this means, it does not only detects the attacks from malicious clients and server forging their logs, but also is able to mitigate those attacks and recover the system from them. In addition, we design new attacks against ContractChecker exploiting various limits in real Blockchain systems (e.g., write unavailability, Blockchain forks, contract race conditions). We analyze and harden the security of ContractChecker protocols against the proposed new attacks. For evaluating the cost, we build a functional prototype of the ContractChecker on Ethereum/Solidity. By experiments on private and public Ethereum testnets, we extensively evaluate the cost of the ContractChecker in comparison with that of existing client-based log auditing works. The result shows the ContractChecker can scale to hundreds of clients and save client costs by more than one order of magnitude.
Jordi Paillissé, Jan Manrique, Guillem Bonet, Alberto Rodríguez-Natal · 6 authors
Inter-domain routing security is of critical importance to the Internet since it prevents unwanted traffic redirections. The current system is based on a Public Key Infrastructure (PKI), a centralized repository of digital certificates. However, the inherent centralization of such design creates tensions between its participants and hinders its deployment. In addition, some technical drawbacks of PKIs delay widespread adoption. In this paper we present IPchain, a blockchain to store the allocations and delegations of IP addresses. IPchain leverages blockchains' properties to decentralize trust among its participants, with the final goal of providing flexible trust models that adapt better to the ever-changing geopolitical landscape. Moreover, we argue that Proof of Stake is a suitable consensus algorithm for IPchain due to the unique incentive structure of this use-case, and that blockchains offer relevant technical advantages when compared to existing systems, such as simplified management. In order to show its feasibility and suitability, we have implemented and evaluated IPchain's performance and scalability storing around 350k IP prefixes in a 2.5 GB chain.
Georgia Avarikioti, Lukas Käppeli, Yuyi Wang, Roger Wattenhofer
We prove Bitcoin is secure under temporary dishonest majority. We assume the adversary can corrupt a specific fraction of parties and also introduce crash failures, i.e., some honest participants are offline during the execution of the protocol. We demand a majority of honest online participants on expectation. We explore three different models and present the requirements for proving Bitcoin's security in all of them: we first examine a synchronous model, then extend to a bounded delay model and last we consider a synchronous model that allows message losses.
Wenli Yang, Erfan Aghasian, Saurabh Garg, David Herbert · 6 authors
The emergence of Internet protocol suites and packet-switching technologies tends to the considerations of security, privacy, scalability, and reliability in layered Internet service architectures. The existing service systems allow us to access big data, but few studies focus on the fundamental security and stability in these systems, especially when they involve large-scale networks with overloaded private information. In this paper, we explored the blockchain-based mechanism that aims to improve the critical features of traditional Internet services, including autonomous and decentralized processing, smart contractual enforcement of goals, and traceable trustworthiness in tamper-proof transactions. Furthermore, we provide a comprehensive review to conceptualize the blockchain-based framework to develop the decentralized protocols for the extensive number of Internet services. This comprehensive survey aims to address blockchain integration to secure Internet services and identify the critical requirements of developing a decentralized trustworthy Internet service. Additionally, we present a case study of the blockchain-based Internet of Things (IoT) for neuro-informatics to illustrate the potential applications of blockchain architectures. Finally, we summarize the trends and challenges of blockchain architectures that benefit a multitude of disciplines across all the Internet service fields of interest.
Jan 1, 2019·Proceedings of the ... Annual Hawaii International Conference on System Sciences/Proceedings of the Annual Hawaii International Conference on System Sciences
A.K.M. Najmul Islam, Matti Mäntymäki, Marja Turunen
This paper investigates the focal actors and their heterogeneity in blockchain splits. Disagreements in blockchain communities often lead to splits in the blockchain and the community. For example, disagreements within the Bitcoin community on increasing the block size led to the blockchain split and creation of Bitcoin Cash. We build on actor-network theory to investigate blockchain split as a translation process, and employ case study methodology to examine Bitcoin splits. We identify several human actors, such as miners, developers, merchants, and investors, as well as non-human actors including ideologies, exchanges and computer programs involved in Bitcoin splits. Our results show that actor heterogeneity, that is, the complex constellation of diverse actors, plays a key role in blockchain splits. We further describe how the human and non-human actors’ fluid moves into micro and macro positions in the network affect the development of the split. We also discuss the role of these actors and their engagement in forming micro and macro agencies in blockchain splits. Our study adds to the understanding of actor behavior and network dynamics in decentralized information systems such as blockchain and open source software.
With the popularity of Bitcoin, there is a greater demand for the scalability of the Bitcoin blockchain, which is susceptible to the efficiency of block propagation. In the Bitcoin blockchain, efficient block propagation approach can reduce the computing power and the risk of forks. Meanwhile, larger blocks help to improve the throughput of transactions. Thus, the block propagation is a major issue of the scalability of the Bitcoin network. This paper introduces a method to reduce the required bandwidth of block propagation with erasure coding. To begin with, the network nodes are classified into several clusters. When a node wants to propagate a block, the node does not need to propagate the whole information of the block. Instead, the node can only transmit the transaction IDs and the coded information to each cluster. The simulation shows that the proposed method can significantly ease the network traffic among these clusters.
Open access
Blockchain Technology Applications and Security
Caching and Content Delivery
Advanced Steganography and Watermarking Techniques
Xintong Ling, Jiaheng Wang, Taha Bouchoucha, Bernard C. Levy · 5 authors
The relentless growth of wireless applications and data traffic continues to accentuate the long felt need for decentralized, self-managed, and cooperative network architectures. Enlightened by the power of blockchain technology, we propose a blockchain radio access network (B-RAN) architecture and develop decentralized, secure, and efficient mechanisms to manage network access and authentication among inherently trustless network entities. We further identify promising advanced functions made possible by adopting blockchain for open radio access networks. Our test results demonstrate the benefits of the B-RAN architecture. We also present a number of challenges and future research directions.
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.
David Derler, Kai Samelin, Daniel Slamanig, Christoph Striecks
Blockchain technologies recently received a considerable amount of attention. While the initial focus was mainly on the use of blockchains in the context of cryptocurrencies such as Bitcoin, application scenarios now go far beyond this. Most blockchains have the property that once some object, e.g., a block or a transaction, has been registered to be included into the blockchain, it is persisted and there are no means to modify it again. While this is an essential feature of most blockchain scenarios, it is still often desirable-at times it may be even legally required-to allow for breaking this immutability in a controlled way.
Edge computing is an important tool for smart computing, which brings convenience to data processing as well as security problems. In particular, the security of data storage under edge computing has become an obstacle to its widespread use. To solve the problem, the mechanism combing blockchain with regeneration coding is proposed to improve the security and reliability of stored data under edge computing. Our contribution is as follows. 1) According to the three-tier edge computing architecture and data security storage requirements, we proposed hybrid storage architecture and model specifically adapted to edge computing. 2) Making full use of the data storage advantages of edge network devices and cloud storage servers, we build a global blockchain in the cloud service layer and local blockchain is built on the terminals of the Internet of things. Moreover, the regeneration coding is utilized to further improve the reliability of data storage in blockchains. 3) Our scheme provides a mechanism for periodically validating hash values of data to ensure the integrity of data stored in global blockchain.
Mazin Debe, Khaled Salah, Muhammad Habib ur Rehman, Davor Svetinović
Public fog nodes extend cloud services for the Internet of Things (IoT) clients and smart devices to provide additional computation capabilities, storage space, and reduce latency and response time. The openness and pervasiveness of public fog nodes leads to the requirement of using trust models to ensure reliability, security, privacy, and meet the service-level agreements (SLAs). Conventional trust models for public fog nodes are centrally configured, deployed, and maintained considering security, privacy, and SLA requirements. However, these trust models enforce centralized governance policies across the system which leads towards the single-point-of-failure and single-point-of-compromise over IoT devices' and users' personal data. This paper proposes a decentralized trust model in order to maintain the reputation of publicly available fog nodes. The reputation is maintained considering users' opinions about their past interactions with the public fog nodes. The proposed trust model is designed using public Ethereum blockchain and smart contract technologies in order to enable decentralized trustworthy service provisioning between IoT devices and public fog nodes. The proposed approach is tested and evaluated in terms of security, performance, and cost. The results show that using blockchain for decentralized reputation management could become more advantageous when compared to the existing centralized trust models.
Sehyun Park, Seongwon Im, Youhwan Seol, Jeongyeup Paek
Bitcoin is a decentralized digital currency that has gained significant attention and growth in recent years. Unlike traditional currencies, Bitcoin does not rely on a centralized authority to control the supply, distribution, and verification of the validity of transactions. Instead, Bitcoin relies on a peer-to-peer (P2P) network of volunteers to distribute pending transactions and confirmed blocks, to verify transactions, and to collectively implement a replicated ledger that everyone agrees on. This P2P network is at the heart of Bitcoin and many other blockchain technologies. In this paper, we present a comparative measurement study of nodes in the Bitcoin network. We measure and analyze how many the so-called “volunteers” are in the Bitcoin P2P network by scanning the live Bitcoin network for 37 days in 2018 and compare them with the data reported by prior work in 2013~2016. This paper is motivated by the fact that Bitcoin has experienced explosive growth in terms of a number of users, transactions, value, and interest over a recent couple of years. Our investigation includes the IP addresses of Bitcoin nodes, size of the network, power law in the geographic distribution, protocol, and client versions, and network latencies and shows how today's network is different from early days. In addition, based on the observations made from the measurement study, we propose a simple distance-based peer selection rule for improved connectivity and faster data propagation. The evaluation results show that our proposed lightweight and backward-compatible peer selection rule has the potential to reduce data dissemination latency.
Open access
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Zhiyi Zhang, Vishrant Vasavada, Randy King, Lixia Zhang
Over the last few years, blockchain-based technologies have flourished in many application areas. One of them is the creation of distributed ledgers where records of immutable objects are widely replicated for both transparency and availability. However, the Proof-of-Work (PoW) approach, a popular gating control that determines who can add new records into a ledger, is deemed infeasible for IoT devices with resource constraints.
Cong T. Nguyen, Dinh Thai Hoang, Diep N. Nguyen, Dusit Niyato · 6 authors
The rapid development of blockchain technology and their numerous emerging applications has received huge attention in recent years. The distributed consensus mechanism is the backbone of a blockchain network. It plays a key role in ensuring the network's security, integrity, and performance. Most current blockchain networks have been deploying the proof-of-work consensus mechanisms, in which the consensus is reached through intensive mining processes. However, this mechanism has several limitations, e.g., energy inefficiency, delay, and vulnerable to security threats. To overcome these problems, a new consensus mechanism has been developed recently, namely proof of stake, which enables to achieve the consensus via proving the stake ownership. This mechanism is expected to become a cutting-edge technology for future blockchain networks. This paper is dedicated to investigating proof-of-stake mechanisms, from fundamental knowledge to advanced proof-of-stake-based protocols along with performance analysis, e.g., energy consumption, delay, and security, as well as their promising applications, particularly in the field of Internet of Vehicles. The formation of stake pools and their effects on the network stake distribution are also analyzed and simulated. The results show that the ratio between the block reward and the total network stake has a significant impact on the decentralization of the network. Technical challenges and potential solutions are also discussed.
The challenge that journalism is facing these days in the Internet mobile environment is greater than ever before. Journalism is losing its revenue structure to platform operators favoring a certain markets, and also the trust of its readers in light of fake news and infected news. To alleviate this situation, we propose a blockchain technology that is applicable to journalism in order to achieve decentralization as a reasonable alternative. The journalism model based on hybrid blockchain aims to achieve the following: the delivery of articles with sharing value, what we call proof of sharing; the distribution of roles of personalized agenda settings; and finally, the use of agora to collect public opinions. With all these, we attempt to resolve the issues with current journalism with our proposed model based on blockchain.
Resource-constrained devices are unable to maintain a full copy of the Bitcoin Blockchain in memory. This paper proposes a bidirectional payment channel framework for IoT devices. This framework utilizes Bitcoin Lightning-Network-like payment channels with low processing and storage requirements. This protocol enables IoT devices to open and maintain payment channels with traditional Bitcoin nodes without a view of the blockchain. Unlike existing solutions, it does not require a trusted third party to interact with the blockchain nor does it burden the peer-to-peer network in the way SPV clients do. The contribution of this paper includes a secure and crypto-economically fair protocol for bidirectional Bitcoin payment channels. In addition, we demonstrate the security and fairness of the protocol by formulating it as a game in which the equilibrium is reached when all players follow the protocol.
Blockchain is defined as a distributed ledger technology that can implement financial models. An improved blockchain provides a democratic virtual economic system (DVES) that can verify payments, reach consensus, and store encrypted data in virtual economic systems. In this paper, we review the latest progress and possibilities in improved blockchain with respect to openness, data security, and scalability. This paper outlines the challenges of value, existence, and status (VES) and the state-of-the-art solutions for improved blockchain. Then, this paper discusses the VES in terms of distributed energy, ownership certification, infrastructure, and other fields. More importantly, it analyzed the importance of scale out, which can be a key enabler to solve the main practical problems in constructing DVES.
Muhammad Salek Ali, Massimo Vecchio, Miguel Pincheira, Koustabh Dolui · 6 authors
The blockchain technology has revolutionized the digital currency space with the pioneering cryptocurrency platform named Bitcoin. From an abstract perspective, a blockchain is a distributed ledger capable of maintaining an immutable log of transactions happening in a network. In recent years, this technology has attracted significant scientific interest in research areas beyond the financial sector, one of them being the Internet of Things (IoT). In this context, the blockchain is seen as the missing link toward building a truly decentralized, trustless, and secure environment for the IoT and, in this survey, we aim to shape a coherent and comprehensive picture of the current state-of-the-art efforts in this direction. We start with fundamental working principles of blockchains and how blockchain-based systems achieve the characteristics of decentralization, security, and auditability. From there, we build our narrative on the challenges posed by the current centralized IoT models, followed by recent advances made both in industry and research to solve these challenges and effectively use blockchains to provide a decentralized, secure medium for the IoT.
Yongjune Kim, Ravi Kiran Raman, Young-Sik Kim, Lav R. Varshney · 5 authors
Blockchain systems store transaction data in the form of a distributed ledger where each peer is to maintain an identical copy. Blockchain systems resemble repetition codes, incurring high storage cost. Recently, distributed storage blockchain (DSB) systems have been proposed to improve storage efficiency by incorporating secret sharing, private key encryption, and information dispersal algorithms. However, the DSB results in significant communication cost when peer failures occur due to denial of service attacks. In this letter, we propose a new DSB approach based on a local secret sharing (LSS) scheme with a hierarchical secret structure of one global secret and several local secrets. The proposed DSB approach with LSS improves the storage and recovery communication costs.
With the recent increase in the number of IoT devices and the development of centralized management systems, risks in cyber space, including personal information phishing, malicious code infection, hacking, and DDos attack, are becoming major issues in the real world. The recently developed distributed data management technology, blockchain, provides reliability in transactions without the intervention of a third party. This new technology, blockchain, promotes integrity and reliability of transaction records by allowing for all network participants to jointly own and verify data, which was previously done by a central server. Due to distributed data management, the technology can reduce brokerage fees and construction costs, and guarantees high levels of integrity and security of data. This paper examines the effective identifier management using blockchain technology under the named data networking environment. The proposed system does not expose a specific user's identifier by creating a transaction using the content name of the identifier. The identifier can be safely stored and managed through such an identifier split management technique.
Open access
Caching and Content Delivery
Blockchain Technology Applications and Security
Advanced Steganography and Watermarking Techniques
Many blockchain consensus protocols have been proposed recently to scale the throughput of a blockchain with available bandwidth. However, these protocols are becoming increasingly complex, making it more and more difficult to produce proofs of their security guarantees. We propose a novel permissionless blockchain protocol OHIE which explicitly aims for simplicity. OHIE composes as many parallel instances of Bitcoin's original (and simple) backbone protocol as needed to achieve excellent throughput. We formally prove the safety and liveness properties of OHIE. We demonstrate its performance with a prototype implementation and large-scale experiments with up to 50,000 nodes. In our experiments, OHIE achieves linear scaling with available bandwidth, providing about 4-10 Mbps transaction throughput (under 8-20 Mbps per-node available bandwidth configurations) and at least about 20x better decentralization over prior works.
Blockchain is a decentralized transaction and data management solution, the technological weapon-of-choice behind the success of Bitcoin and other cryptocurrencies. As the number and variety of existing blockchain implementations continues to increase, adopters should focus on selecting the best one to support their decentralized applications (dApps), rather than developing new ones from scratch. In this paper we present a framework to aid software architects, developers, tool selectors and decision makers to adopt the right blockchain technology for their problem at hand. The framework exposes the correlation between technological decisions and architectural features, capturing the knowledge from existing industrial products, technical forums/blogs, experts' feedback and academic literature; plus our own experience using and developing blockchain-based applications. We validate our framework by applying it to dissect the most outstanding blockchain platforms, i.e., the ones behind the top 10 cryptocurrencies apart from Bitcoin. Then, we show how we applied it to a real-world case study in the insurtech domain.