Matteo Varvello, Iñigo Querejeta Azurmendi, Antonio Nappa, Panagiotis N. Papadopoulos · 6 authors
Distributed Virtual Private Networks (dVPNs) are new solutions aiming to solve the trust-privacy concern of a VPN's central authority by leveraging a distributed architecture. In this paper, we discuss the requirements of a successful dVPN system and we present VPN-Zero: a dVPN system with strong privacy guarantees that provides traffic accounting and has minimal performance impact on its users. VPN-Zero guarantees that a dVPN node only carries traffic it has “allowlisted”, without revealing its allowlist or knowing the traffic it tunnels. This is achieved via three main innovations: (a) an attestation mechanism which leverages TLS to certify a user visit to a specific domain, (b) a zero-knowledge proof to certify that some incoming traffic is authorized (e.g., falls in a node's allowlist, without disclosing the target domain), and (c) a dynamic chain of VPN tunnels to both increase privacy and guarantee service continuation while traffic certification is in place. The paper demonstrates VPN-Zero functioning when integrated with two production systems: BitTorrent's Distributed Hash Table and ProtonVPN. Early evaluation results show that the median setup time of VPN-Zero is about 10 seconds.
Permissionless computation is one of the missing pieces in the web3 stack in order to have all the tools needed to “decentralise Internet services”. There are already proposals to embed computation in decentralised networks like smart contracts, or blockchain networks for computational offloading. Although technically sound, their computational model is too restrictive to be used for general purpose computation. In this paper, we propose a general architecture of a decentralised network for general-purpose and permissionless computation based on content-addressing. We present a proof-of-concept prototype and describe in detail its building blocks.
In recent years, China's charity exposed a variety of problems, which caused a trust crisis towards China's charity among public, and further led to China's charity once deadlocked. This paper designs a charity donation system by using blockchain distributed ledger and software engineering method, aiming to use blockchain to get through the related links of charity donation, so as to improve the transparency and credibility of donation behavior.
We previously proposed a cross-referencing method for enabling multiple peer-to-peer network domains to manage their own public blockchains and periodically exchanging the state of the latest fixed block in the blockchain with hysteresis signatures among all the domains via an upper network layer. In this study, we evaluated the effectiveness of our method from three theoretical viewpoints: decentralization, scalability, and tamper resistance. We show that the performance of the entire system can be improved because transactions and blocks are distributed only inside the domain. We argue that the transaction processing capacity will increase to 56,000 transactions per second, which is as much as that of a VISA credit card system. The capacity is also evaluated by multiplying the number of domains by the average reduction in transaction-processing time due to the increase in block size and reduction in the block-generation-time interval by domain partition. For tamper resistance, each domain has evidence of the hysteresis signatures of the other domains in the blockchain. We introduce two types of tamper-resistance-improvement ratios as evaluation measures of tamper resistance for a blockchain and theoretically explain how tamper resistance is improved using our cross-referencing method. With our method, tamper resistance improves as the number of domains increases. The proposed system of 1,000 domains are 3-10 times more tamper-resistant than that of 100 domains, and the capacity is 10 times higher. We conclude that our method enables a more scalable and tamper-resistant public blockchain balanced with decentralization.
This paper presents iBatch, a middleware system running on top of an operational Ethereum network to enable secure batching of smart-contract invocations against an untrusted relay server off-chain. iBatch does so at a low overhead by validating the server's batched invocations in smart contracts without additional states. The iBatch mechanism supports a variety of policies, ranging from conservative to aggressive batching, and can be configured adaptively to the current workloads. iBatch automatically rewrites smart contracts to integrate with legacy applications and support large-scale deployment. For cost evaluation, we develop a platform with fast and cost-accurate transaction replaying, build real transaction benchmarks on popular Ethereum applications, and build a functional prototype of iBatch on Ethereum. The evaluation results show that iBatch saves 14.6%-59.1% Gas cost per invocation with a moderate 2-minute delay and 19.06%-31.52% Ether cost per invocation with a delay of 0.26-1.66 blocks.
Abstract In today's scenario, many news related to counterfeit land titles, fraud land registry, delay in ownership transfer, the involvement of government officers in fraudulent activities is frequently being heard. However, this depicts that the existing land registry system is not efficient to provide security and timely settlement of transactions between the seller and buyer. To solve this problem, we proposed a blockchain‐based land registry system in this article. The specialty and popularity of blockchain technology is its transparency and security. Blockchain is being inculcated with the trait of persistence, immutability, decentralization. Its ascent to new opportunity of efficiency and cost saving. It can provide right framing for digital asset, online payment, and transfer of remittance. Additional to this it can check upon black money laundering. Enterprise that can use blockchain technology can gain faith of consumer. In this article, we proposed a decentralized application. In particular, for creating and deploying the smart contract, we used Ethereum network. The deployed contracts are interacted through frontend web pages. React is used for the development of web page. For server and routing purposes, Next.js is used. Finally, the results and analysis show that our proposed model is efficient and viable.
Lorenzo Ghiro, Francesco Restuccia, Salvatore D’Oro, Stefano Basagni · 7 authors
The term blockchain is used for disparate projects, ranging from cryptocurrencies to applications for the Internet of Things (IoT). The concept of blockchain appears therefore blurred, as the same technology cannot empower applications with extremely different requirements, levels of security and performance. This position paper elaborates on the theory of distributed systems to advance a clear definition of blockchain allowing us to clarify its possible role in the IoT. The definition binds together three elements that, as a whole, delineate those unique features that distinguish the blockchain from other distributed ledger technologies: immutability, transparency and anonymity. We note that immutability-which is imperative for securing blockchains-imposes remarkable resource consumption. Moreover, while transparency demands no confidentiality, anonymity enhances privacy but prevents user identification. As such, we raise the concern that these blockchain features clash with the requirements of most IoT applications where devices are power-constrained, data needs to be kept confidential, and users to be clearly identifiable. We consequently downplay the role of the blockchain for the IoT: this can act as a ledger external to the IoT architecture, invoked as seldom as possible and only to record the aggregate results of myriads of local (IoT) transactions that are most of the time performed off-chain to meet performance and scalability requirements.
In this paper, we propose a decentralised double blockchain (DB) architecture for scalable, lightweight and secure Internet-of-Things (IoT) information and reputation management. We consider a heterogeneous cloud and fog IoT communication network where the information blockchain (IB) stores IoT data in the cloud layer due to limited storage resources in the fog layer and a lightweight reputation blockchain (RB) stores reputations in the fog layer to quickly identify the trust levels of IoT devices. Furthermore, we propose a fog layer DB node classification algorithm to improve the efficiency of IB and RB generation and RB storage in the fog layer. To improve security, we propose a mapping algorithm between the short RB and long IB to securely validate the reputation data based on corresponding IoT device data, and quickly identify malicious tampering of the DB. Experimental simulation results highlight the storage scalability, low latency propagation, and security of our DB architecture compared to conventional single blockchains.
The full-replication data storage mechanism, as commonly utilized in existing blockchains, suffers from poor scalability, since it requires every node to preserve a complete copy of the whole block data locally to tolerant potential Byzantine failures. In a hostile environment, the malicious node may discard or tamper data deliberately. Thus, existing distributed storage method, which partitions data into multiple parts and distributes them over all nodes, cannot suit for blockchains. This demonstration showcases BFT-Store, a novel distributed storage engine for blockchains to break full-replication by integrating erasure coding with Byzantine Fault Tolerance (BFT) consensus protocol. This demonstration will (\romannumeral1) allow audience members to see how BFT-Store partitions block data over all nodes to reduce the storage occupation of system, and (\romannumeral2) allow audience members to see how BFT-Store recovers blocks under distributed scenario even with Byzantine failure.
Blockchain technologies can enable secure computing environments among mistrusting parties. Permissioned blockchains are particularly enlightened by companies, enterprises, and government agencies due to their efficiency, customizability, and governance-friendly features. Obviously, seamlessly fusing blockchain and cloud computing can significantly benefit permissioned blockchains; nevertheless, most blockchains implemented on clouds are originally designed for loosely-coupled networks where nodes communicate asynchronously, failing to take advantages of the closely-coupled nature of cloud servers. In this paper, we propose an innovative cloud-oriented blockchain -- CloudChain, which is a modularized three-layer system composed of the network layer, consensus layer, and blockchain layer. CloudChain is based on a shared-memory model where nodes communicate synchronously by direct memory accesses. We realize the shared-memory model with the Remote Direct Memory Access technology, based on which we propose a shared-memory consensus algorithm to ensure presistence and liveness, the two crucial blockchain security properties countering Byzantine nodes. We also implement a CloudChain prototype based on a RoCEv2-based testbed to experimentally validate our design, and the results verify the feasibility and efficiency of CloudChain.
The inclusion of resource sharing schemes within Network Function Virtualization (NFV) ecosystems allows for optimized usage of 5G infrastructure and extended capabilities of network slicing services. In such environments, marketplaces are formed to facilitate the exchange of NFV services across administrative domains, which may, however, belong to untrusted and unreliable entities. In this work, we propose a novel zero-touch approach for cross-domain network slicing service assurance, using enterprise blockchain technologies and employing an AI-driven closed-loop automation architecture. Our approach is based on the lifecycle management of Service Level Agreements (SLAs) using smart contracts-from service negotiation to service binding, monitoring, reconfiguration and decommissioning. Our closed-loop architecture is materialized using Cloud-Native operational Data Lakes and allows to continuously monitor the status and health of exchanged services and to detect or predict SLA violations so that immediate mitigation actions are taken to ensure service continuity. The proposed approach is applied in real Content Distribution Networks scenarios within the European project 5GZORRO and our experimental results demonstrate the ability of our system to accurately predict changes in service demand and to timely respond with preventive scaling actions.
Adriana Fernández–Fernández, Michael De Angelis, Pietro G. Giardina, James C. Taylor · 10 authors
To fully cope with the requirements of innovative 5G use cases, evolving business models and flexible networking scenarios spanning multiple administrative domains are envisioned. In this context, transparent and trusted frameworks that enable network service providers and infrastructure providers to advertise, negotiate and acquire, in real time, 5G resources and services, distributed over various geographical areas, are extremely valuable. To address this goal, emerging Distributed Ledger Technologies (DLTs) arise as well-suited solutions to ensure distributed security and trust, as well as effective and agile transaction management across the various parties involved in the 5G service chain implementation. Following this vision, this paper presents the design of a DLT-enabled Marketplace aimed to foster the secure trading of heterogeneous resources in dynamic 5G ecosystems. The performance of an initial implementation as proof-of-concept is also analyzed. The results of this proof-of-concept validate the feasibility of a decentralized marketplace implementation in the context of 5G resource trading.
Blockchain technology has become increasingly popular as the internet of things (IoT) has grown in popularity. Over NDN(Named Data Networking), blockchain provides an innovative technique to preserve reliable records without relying on a community blockchain machine. A decentralized network and data management has been established throughout the community by utilizing blockchain is proposed in this paper. Moreover, this research work has developed a trust model to enhance the trustworthiness of messages by relying on the popularity of the sender based on parallel mining. Blockchain has been determined as growing generation for establishing decentralized and transactional information sharing throughout a big community of untrusted people. It permits the advent of decentralized surroundings, in which transaction and data below the manipulation of any one third of the party organization. Some transactions are always completed in a public account in a checkable, visible, and permanent manner, accompanied by a stamp and other data. The work gives the comparative analysis on serial mining and parallel mining of data by using blockchain. Also in the study, it is proven that, parallel mining outperforms well when compared to the serial mining of data.
Blockchain technology is gaining popularity in industries and governments for information monitoring, distribution, and tracking. Thanks to the built-in security properties, blockchain provides security integrity to various decentralized applications (dApps) involving distributed operations including supply chain, healthcare, banking, internet of things (IoT), and networking. In this paper, we propose a generic blockchain framework (GBF) for applying two blockchains to the dApp systems, one to establish trust and the other to use the trust for securing applications. GBF provides a generally applicable framework and addresses the foundational questions of the blockchain objectives, participants, and the underlying distributed consensus protocol in use. We apply GBF to various case studies from the recent blockchain research to show its effectiveness and generality. We also prototype GBF using smart contract and experiment on CloudLab for preliminary evaluations focusing on the application-general metrics. We propose GBF to facilitate blockchain/dApp research and development by providing the initial framework and enable the preliminary analyses so that the decentralized applications with specific aims can build on GBF.
Blockchain is a distributed ledger technology based on the underlying peer-to-peer network. In this paper, we focus on improving the chances of a transaction being packaged into a valid block so as to be recorded on the main chain. Blockchain nodes typically broadcast transactions they receive to the whole network. Hence, for recording transactions on the blockchain more efficiently, it becomes essential to determine influential nodes to publish transactions, where influential nodes are more actively involved in mining, recording, or broadcasting transactions in the network. To that aim, we propose an Influential Node Determination Framework (INDF) using a series of significant factors, such as hash rate, latency, active time, and degree of a node. Specifically, INDF consists of two parallel schemes: the first scheme figures out influential pools according to their hash rates where a truth-telling mechanism design is employed to encourage the pool nodes to report their true hash rate values; the second one determines influential individual nodes based on an improved L-H index algorithm. Remarkably, the proposed truth-telling mechanism is proved to be incentive-compatible. Our improved L-H index algorithm is comparatively studied to reflect the impacts of different node parameters on the node’s ranking. Extensive experiments are conducted to demonstrate the effectiveness of our proposed framework.
Financial institutions have made lives easier for a lot of individuals and organizations that would earlier use to face capital shortage now and then. Therefore, it becomes necessary to make the financial systems more reliable, secure, time-conserving, and cost-effective. Although several approaches have already been proposed, all of these tend to fail on at least one of the key features, i.e., trust. Motivated by this, in this paper, we propose DeLend, an Ethereum blockchain-based peer-to-peer (P2P) lending system. In DeLend, the problems of security, trust, and reliability have been solved with the help of Ethereum-based smart contracts (SCs). To make the system middlemen-free and much more cost-effective, we use the interplanetary file system (IPFS) protocol as a data storage. Through extensive simulation, we show that DeLend requires less bandwidth, which makes it a suitable enabling technology for the next generation of cellular networks, i.e. 6G. Finally, DeLend’s performance evaluation demonstrates its efficacy compared to traditional lending schemes.
Abstract Miners in various blockchain-backed cryptocurrency networks compete to maintain the validity of the underlying distributed ledgers to earn the bootstrapped cryptocurrencies. With limited hashing power, each miner needs to decide how to allocate their resource to different cryptocurrencies so as to achieve the best overall payoff. Together all the miners form a hashing power allocation game. We consider two settings of the game, depending on whether each miner can allocate their fund to a risk-free asset or not. We show that this game admits unique pure Nash equilibrium in closed-form for both settings.
Smart contract (SC) is a user-defined program code over blockchain, which holds the characteristics of immutability and auditability without requiring trust third party and is crucial to provide in-network computation for green applications. Herein we investigate the interactions among the SCs, where the functions defined in one SC are called by another one. The existing work, Ethereum name service (ENS), provides a method to map human-readable names to machine-readable addresses. However, it still suffers the problems induced from the ossification of SC, such as no mechanism to call functions in a non-existing SC, to update SC, to acquire the SC information (e.g. contract application binary interface and address), and to achieve access control. To solve these problems, we propose a flexible smart contract interaction framework with access control (FSCC), where SC name and information are separately stored at blockchain and the distributed off-chain storage to reduce on-chain storage overhead. With the FSCC, interactions with non-existing SC, update of SC, and access control of SC can be achieved. Furthermore, performance evaluations show that on-chain storage overhead can be greatly reduced with keeping the communication delay at a low level.
Saeideh G. Motlagh, Jelena Mišić, Vojislav B. Mišić
Selfish mining is a recognized misbehaving attack in Bitcoin. Selfish miners intentionally delay the release of newly mined blocks with the goal of gaining more revenue. While several studies have been devoted to analyzing the selfish miner behavior, the impact of selfish behavior on Bitcoin network performance has received little to no attention at all. In this work, we focus on that impact using a Markov chain that models selfish behavior both from the aspect of mining and form the aspect of block distribution time. We find that blocks mined by honest miners undergo longer distribution time compared to blocks mined by selfish miners. This delay results in intentional forking and the resulting network inconsistency provides more opportunity for selfish miners to gain unfair revenue.
I. R. Fedorov, Aleksandr Pimenov, G. A. Panin, Sergey Bezzateev
Usage of blockchain in fifth generation mobile networks give opportunities to improve security, privacy and service quality. In spite of all these advantages blockchain technology has a set of disadvantages as low bandwidth and transactions' high latency. Private blockchain has a set of differences which can solve these challenges. In this paper experiment within which compare two popular blockchain (private and public) is described. The goal of experiment to show that private blockchain is able for usage in mobile networks.