Mengting Liu, F. Richard Yu, Yinglei Teng, Victor C. M. Leung · 5 authors
Blockchain technology has been applied in a variety of fields due to its capability of establishing trust in a decentralized fashion. However, the application of blockchain in wireless mobile networks is hindered by a major challenge brought by the proof-of-work puzzle during the mining process, which sets a high demand for the computational capability and storage availability in mobile devices. To address this problem, we propose a novel mobile edge computing (MEC) enabled wireless blockchain framework where the computation-intensive mining tasks can be offloaded to nearby edge computing nodes and the cryptographic hashes of blocks can be cached in the MEC server. Particularly, two offloading modes are considered, i.e., offloaded to the nearby access point or a group of nearby users. First, we conduct the performance analysis of each mode with stochastic geometry methods. Then, the joint offloading decision and caching strategy is formulated as an optimization problem. Furthermore, an alternating direction method of multipliers based algorithm is utilized to solve the problem in a distributed manner. Finally, simulation results demonstrate the effectiveness of our proposed scheme.
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
Existing permissioned blockchain systems designate a fixed and explicit group of committee nodes to run a consensus protocol that confirms the same sequence of blocks among all nodes. Unfortunately, when such a permissioned blockchain runs in a large scale on the Internet, these explicit committee nodes can be easily turned down by denial-of-service (DoS) or network partition attacks. Although work proposes scalable BFT protocols that run on a larger number of committee nodes, their efficiency drops dramatically when only a small number of nodes are attacked. In this paper, our EGES protocol leverages Intel SGX to develop a new abstraction called "stealth committee", which effectively hides the committee nodes into a large pool of fake committee nodes. EGES selects a distinct group of stealth committee for each block and confirms the same sequence of blocks among all nodes with overwhelming probability. Evaluation on typical geo-distributed settings shows that: (1)EGES is the first permissioned blockchain's consensus protocol that can tolerate tough DoS and network partition attacks; and (2) EGES achieves comparable throughput and latency as existing permissioned blockchains' protocols
An insurance system based on blockchain is proposed for web identity security, which provides two insurance service models for personal web identity security of end users and data security of commercial websites, respectively. Claim evidences are uploaded automatically to the blockchain to keep their authenticity. Smart contracts are automatically applied between insurers and policyholders to build trust between them.
Designing blockchain architecture is still an open question and encounters a lot of challenges such as scalability, security, high utilization and so on. In this paper, we propose Chameleon, a scalable and adaptive permissioned blockchain architecture. We adopt the principles of non-forking, high security, scalable and high utilization to design the Chameleon to be suitable for next generation blockchain architecture. In Chameleon, we introduce credit value which can only be acquired through honest behavior to enhance the security of the consensus algorithm. We also introduce the QoS of transactions to meet the various needs of different users. While previous work using sharding to improve the scalability, they either store all transactions in every area or just work independently, it either causes too much redundant data or low resource utilization. Combined with the cloud storage, Chameleon partition the nodes into different area according to different scenario, every area process their own transactions and can also cooperate with each other dynamically to improve transaction throughput and resource utilization.
Ziyan Wang, Xinghua Dong, Yi Li, Li Fang · 5 authors
It is a research hotspot that using blockchain technology to solve the security problems of the Internet of Things (IoT). Although many related ideas have been proposed, there are very few literatures with theoretical and data support. This paper focuses on the research of model construction and performance evaluation. First, an IoT security model is established based on blockchain and InterPlanetary File System (IPFS). In this model, many security risks of traditional IoT architectures can be avoided, and system performance is significantly improved in distributed large capacity storage, concurrency and query. Secondly, the performance of the proposed model is evaluated through the average latency and throughput, which are meaningful for further research and optimization of this direction. Analysis and test results demonstrate the effectiveness of the blockchain-based security model.
Named Data Networking is built with security which requires each named Data object to be digitally signed by its producer. Thus, the NDN project has proposed a key management model on NDN testbed for verification of the Data packet to be immune to distributing poisoned content. However, in practice, this model poses two challenges for verifying fake content: (1) the centralized architecture easily leads to a single point of failure, especially when the root key fails, its difficult to verify the keys across sites due to the lack of trust between them, and (2) excessive overhead of certificate chain traversal when verifying signature. This paper first proposes a blockchain-based key management scheme in NDN to address the problem of lack of mutual trust between sites without trust anchors. Specifically, all site nodes form a permissioned blockchain for storing public key hashes to ensure the authenticity, and the proxy gateway participates in verifying to reduce excessively frequent communication between the router and the blockchain. In addition, the NDN public key content object and the scheme of their storage, verification, and revocation are redesigned. The result of our analysis and evaluation shows that the proposed scheme is capable of supporting less verification numbers and higher verification efficiency.
With the development of internet of things (IoT) network in recent years, while the centralization data management brings longer delay while has more safety troubles. Moreover, once a single device is attacked, the system crashes. So, blockchain technique which could realize safety distributed data management is introduced. However, the consensus mechanism of blockchain consumes huge computation resources. And the storage of entire ledger also consumes huge storage resources of the blockchain nodes. Due to the limited capacity of IoT devices, the nodes cannot afford the computation resources to reach consensus and caching resources. This paper introduces an architecture of edge computing based blockchain network which makes use of the computation and caching capacity of edge server to help the IoT devices in reaching consensus and storing data.
Ee Hong Aw, Ralucca Gera, Kenneth S. Hicks, Nicholas Koeppen · 5 authors
Due to the anonymous and remote nature of Electronic Commerce (E-commerce), reviews of products and vendors left by previous customers have emerged as an integral part of most online transactions. The reviews may influence the decision of customers buying the product since E-commerce websites/services do not allow customers to validate and inspect products in-store. In this paper, we analyze data from two BITCOIN marketplaces which include transactions between marketplace users and the ratings of those transactions given by those users. In this analysis we create a synthetic network model with similar topological properties as the networks of the interactions of both marketplaces. The results of our analysis show an interesting phenomenon in which user ratings, which range from -10 to 10, converge to a value of approximately two as the number of a user's transactions increase. Finally, we suggest future work on our synthetic model to improve its agreement with the transaction networks in order to better understand how reviews influence user decisions on transactions.
James Clay, Alexander Hargrave, Ramalingam Sridhar
We investigate the impact of how a cryptocurrency mining system can affect the power consumption of mobile devices. Specifically we look at CoinHive, a cryptocurrency miner and associated mining pool targeting the Monero (XMR) cryptocurrency. CoinHive distributes a JavaScript-based miner to webpages where visitors run the script and provide computing power to the web host's CoinHive account. Ideally, hosting JavaScript-based cryptocurrency miners provides alternatives to using ad-networks as a source of website revenue. While some users may not oppose an energy for advertisement trade-off, it may be less palatable to mobile users concerned with battery life. Our initial studies have revealed that, at a minimum, running the normally distributed JavaScript-based miner increases the power draw of a Samsung Galaxy S4 by about 5 fold. Under certain circumstances, the power draw can increase to eleven-fold. We illustrate these findings by comparing them with various normal use benchmarks and with a variety of different ad-enabled webpages.
Aug 1, 2018·2018 17th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/ 12th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE)
Blockchain is the shared distributed ledger to record the history of transactions. In blockchain network, nodes validate the transactions and reach the consensus on the ordered transactions. The more transactions are happened, the more processing powers of nodes are needed. Shard is introduced to blockchain for processing the multiple transactions in parallel. In this paper, we propose the blockchain for a domain based static sharding. We split a blockchain into multiple shards based on the domain. In each shard, nodes validate the multiple transactions concurrently and keep the shard's ledger separately. With this, it can be processing of low-latency transaction. Also, by changing the composition of committee members that validate blocks dynamically, we can enable the blockchain to be more trust.
Aug 1, 2018·2018 17th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/ 12th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE)
In this paper, we focus on the efficiency improvement of the content distribution network while endow this framework with controllability, where CHs(Content Helpers) have restricted distribution scope and thus the economic benefits of CP(Content Provider) are protected. We propose a novel controllable content distribution framework by using the blockchain technology as well as the iterative self organizing data analysis techniques algorithm (ISODATA), which is an improved k-means clustering method. To implement an incentive and consensus mechanism utilizing proof-of-stake, we employ smart contract to enforce content distribution in an autonomous way. We conduct some experiments to verify the validity and feasibility of the proposed framework. The experimental results demonstrated show that our framework has the advantages of high efficiency, low latency, and good scalability.
Aug 1, 2018·2018 17th IEEE International Conference On Trust, Security And Privacy In Computing And Communications/ 12th IEEE International Conference On Big Data Science And Engineering (TrustCom/BigDataSE)
Saqib Ali, Guojun Wang, Bebo White, Roger Leslie Cottrell
The blockchain is an innovative technology which opened doors to new applications for solving numerous problems in distributed environments. In this work, we design a blockchain-based data storage and access framework for PingER (worldwide end-to-end Internet performance measurement project) to remove its total dependence on a centralized repository. We use the permissioned blockchain and Distributed Hash Tables (DHT) for this purpose. In the proposed framework, metadata of the files are stored on the blockchain whereas the actual files are stored off-chain through DHT at multiple locations using a peer-to-peer network of PingER Monitoring Agents. This will provide decentralized storage, distributed processing, and efficient lookup capabilities to the PingER framework.
Blockchain technology is ushering in another break-out year, the challenge of blockchain still remains to be solved. This paper analyzes the features of Bitcoin and Bitcoin-NG system based on blockchain, proposes an improved method of implementing blockchain systems by replacing the structure of the original chain with the graph data structure. It was named GraphChain. Each block represents a transaction and contains the balance status of the traders. Additionally, as everyone knows all the transactions in Bitcoin system will be baled by only one miner that will result in a lot of wasted effort, so another way to improve resource utilization is to change the original way to compete for miner to election and parallel mining. Researchers simulated blockchain with graph structure and parallel mining through python, and suggested the conceptual new graph model which can improve both capacity and performance.
Peer-to-Peer (P2P) networking is a decentralized network topology that enables parties to communicate directly without central servers. The main obstacle preventing the heavy deployment of the P2P topology is the Network Address Translation (NAT) which serves as a solution for the exhaustion of IPv4 addresses. Methods proposed by the Internet Engineering Task Force (IETF) to solve the NAT traversal issues include Simple Traversal of UDP through NATs (STUN) and Traversal Using Relay NAT (TURN). STUN is limited by the type of deployed NAT, and TURN is limited by the peers' discovery mechanism which is application dependent. In this paper we propose a Blockchain-based platform that enables TURN servers to act as relays for Internet of Things (IoT) devices behind NAT. It also provides End-to-End (e2e) security for Constrained and Non-Constrained IoT devices. Results showed that the system has minimal impact on the existing network and can be a potential solution for advancing IoT deployment.
In blockchain systems, especially cryptographic currencies such as Bitcoin, the double-spending and Byzantine-general-like problem are solved by reaching consensus protocols among all nodes. The state-of-the-art protocols include Proof-of-Work, Proof-of-Stake and Delegated-Proof-of-Stake. Proof-of-Work urges nodes to prove their computing power measured in hash rate in a crypto-puzzle solving competition. The other two take into account the amount of stake of each nodes and even design a vote in Delegated-Proof-of-Stake. However, these frameworks have several drawbacks, such as consuming a large number of electricity, leading the whole blockchain to a centralized system and so on. In this paper, we propose the conceptual framework, fundamental theory and research methodology, based on artificial intelligence technology that exploits nearly complementary information of each nodes. And we designed a particular convolutional neural network and a dynamic threshold, which obtained the super nodes and the random nodes, to reach the consensus. Experimental results demonstrate that our framework combines the advantages of Proof-of-Work, Proof-of-Stake and Delegated-Proof-of-Stake by avoiding complicated hash operation and monopoly. Furthermore, it compares favorably to the three state-of-the-art consensus frameworks, in terms of security and the speed of transaction confirmation.
The decentralized nature of existing and future wireless network topologies has opened some unique opportunities for DLT to play a role in communications. In this column, we have reviewed the basic operation of a consensus mechanism, as well as the current trend of a DLT-based security model that is particularly important for loT. We further point out that, beyond application layer and security, DLT also has potential in other aspects of wireless networking such as computing and radio connectivity. Specifically, we see DLT as a perfect tool that should be leveraged to realize fog -RAN, as the consensus mechanism of DLT may be used to maintain tight synchronization among computing and networking resources in different locations. On the other hand, DLT could also be employed to avoid potential collision that may occur in grant -free uplink access. In summary, we believe that DLT will gradually become a key tool to reshape communication systems in a wide range of aspects, covering not just applications and security, but also connectivity and computing.
With their innovative and fundamentally liberalising approach to data storage, distributive ledger technologies (DLTs) like blockchain—and other associated technologies offer immense benefits to both the public and private sectors, not least in terms of upping efficiency. Lovers of freedom should also note, however, that they offer an important chance to empower individuals in their necessary engagements with the state, and to rebuild societal trust for the common good. In this paper, we propose the establishment of a UK-based international blockchain competition, and a public-facing **‘Chief Blockchain Officer.’** We also propose a UK **‘blockchain departmental target’**: a long-term aim for government departments to make a 1% efficiency saving by embracing blockchain and other associated innovative technologies. A renewed UK focus on efficiency and the opportunities of new technology would be inspirational, and we look forward to discussing these proposals, and carrying out further research into Distributed Ledger Technologies.
The user can organize a social network together with other peoples, in the manner of the consortium blockchain, so that expected contents can be accessed via collecting pieces of data (sub-flows) from members. This promising mechanism heavily relies on the multipath data transmission to transfer sub-flows to the user over the social network. However, the performance differentiation and link overlapping of transmission paths between the user and members could result in severe traffic congestion and packet scrambling. To solve these problems, we design a novel SDN (Software-Defined Networking)-based framework because the global traffic engineering can perform more flexible flow transferring. Our SDN controller has three modules of topology discovery, sub-flow association and path selection. We quickly capture the social network from the most appropriate consortium blockchain where a set of paths with minimal link overlapping and performance differentiation can be found to transfer correlated sub-flows the user wants. The simulation results show that our solution achieves a higher network throughput compared with traditional methods while guaranteeing a low data retransmission rate.
Existing service ecosystems typically rely on some centralized service registries (e.g., ProgrammableWeb.com) as "middle people" to record service behaviors thus to provide service ranking and recommendation. Excessive centralization increasingly becomes the bottleneck and hinders the further growth of the service ecosystems. As the first attempt to apply the fundamental technique underneath the emerging Bitcoin network into the field of service oriented computing, this paper proposes to build a service ecosystem as a decentralized blockchain-oriented service network, called Decentralized Service Eco-System (DSES). Whenever any activity occurs in the system (e.g., APIs are used together in a published mashup), all involved parties will individually store and maintain a copy of the detailed record (provenance) at their local databases. Such a distributed database-oriented solution will enable services who do not fully trust each other to maintain a set of global states. In this way, service discovery and recommendation can be realized in a distributed manner that promises higher scalability and maintainability. As a proof of concept, a prototyping system of DSES is constructed using the real-world data from ProgrammableWeb.com, based on the INKchain, a newly open-source consortium blockchain mechanism extending the Hyperledger Fabric.
Jul 1, 2018·2018 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData)
Secure naming systems, or more narrowly public key infrastructures (PKIs), form the basis of secure communications over insecure networks. All security guarantees against active attackers come from a trustworthy binding between user-facing names, such as domain names, to cryptographic identities, such as public keys. By offering a secure, distributed ledger with highly decentralized trust, blockchains such as Bitcoin show promise as the root of trust for naming systems with no central trusted parties. PKIs based upon blockchains, such as Namecoin and Blockstack, have greatly improved security and resilience compared to traditional centralized PKIs. Yet blockchain PKIs tend to significantly sacrifice scalability and flexibility in pursuit of decentralization, hindering large-scale deployability on the Internet. We propose Conifer, a novel PKI with an architecture based upon CONIKS, a centralized transparency-based PKI, and Catena, a blockchain-agnostic way of embedding a permissioned log, but with a different lookup strategy. In doing so, Conifer achieves decentralized trust with security at least as strong as existing blockchain-based naming systems, yet without sacrificing the flexibility and performance typically found in centralized PKIs. We also present our reference implementation of Conifer, demonstrating how it can easily be integrated into applications. Finally, we use experiments to evaluate the performance of Conifer compared with other naming systems, both centralized and blockchain-based, demonstrating that it incurs only a modest overhead compared to traditional centralized-trust systems while being far more scalable and performant than purely blockchain-based solutions.
Frank Yeong‐Sung Lin, Chiu‐Han Hsiao, Yean‐Fu Wen, Yang-Che Su
Transactions and blocks must be synchronized among the blockchain miners on the Internet. Software-defined networking and network function virtualization techniques support dynamically assigning computing resources into servers of the core and edge clouds. In this paper, an adaptive broadcast algorithm is proposed for blockchain authentication, authorization, and accounting (AAA) services. The cryptography is propagated throughout the Internet by using a broadcast mechanism. The broadcast message may incur a propagation delay and duplicate transmissions. The total propagation delay is assumed to be a combination of transmission time and computational time for data verification. A mathematical programming model is formulated to address the secure broadcast problem as a minimum spanning tree problem. The objective is to minimize the processing and transmission delay through reduced duplicate transmissions. Computational experiments demonstrate proof of concept to adopt blockchain techniques. The dynamic AAA architecture and path selection enable the blockchain operator to efficiently make decisions and achieve more secure services.
Jul 1, 2018·2018 IEEE International Conference on Internet of Things (iThings) and IEEE Green Computing and Communications (GreenCom) and IEEE Cyber, Physical and Social Computing (CPSCom) and IEEE Smart Data (SmartData)
With the development of Internet of Things (IoT) and blockchain technologies, people find more and more blockchain applications in the IoT domain. While it is reasonable that IoT systems use hierarchical network structures, their sheer large scales may lead to hundreds or even thousands of non-leaf nodes, which may serve as full nodes when participating in IoT blockchains. From IoT blockchain design perspective, it is important to understand the scalability of the energy consumption feature of IoT blockchains. In our research we have collected real-world data that reflect the energy consumption features of several consensus algorithms of blockchain. In this work-in-progress paper, we report our results based on linear regression models. These models provide reference estimations of the energy consumption impact in designing blockchains for IoT systems.