Chainlink 2.0: Next Steps in the Evolution of Decentralized Oracle Networks
Authors: Lorenz Breidenbach, Christian Cachin, Alex Coventry, Steve Ellis, Ari Juels, Benedict Chan, Farinaz Koushanfar, Daniel Moroz, Florian Tramèr, Andrew Miller, Sergey Nazarov, Brendan Magauran, Alexandru Topliceanu, and Fan Zhang
In this whitepaper, we articulate a vision for the evolution of Chainlink beyond its initial conception in the original Chainlink whitepaper. We foresee an increasingly expansive role for oracle networks, one in which they complement and enhance existing and new blockchains by providing fast, reliable, and confidentiality-preserving universal connectivity and off-chain computation for smart contracts.
The foundation of our plan is what we call Decentralized Oracle Networks, or DONs for short. A DON is a network maintained by a committee of Chainlink nodes. It supports any of an unlimited range of oracle functions chosen for deployment by the committee. A DON thus acts as a powerful abstraction layer, offering interfaces for smart contracts to extensive off-chain resources and highly efficient yet decentralized off-chain computing resources within the DON itself.
With DONs as a springboard, Chainlink plans to focus on advances in seven key areas:
• Hybrid smart contracts: Offering a powerful, general framework for augmenting existing smart contract capabilities by securely composing on-chain and off-chain computing resources into what we call hybrid smart contracts.
• Abstracting away complexity: Presenting developers and users with simple functionality eliminates the need for familiarity with complex underlying protocols and system boundaries.
• Scaling: Ensuring that oracle services achieve the latencies and throughputs demanded by high-performance decentralized systems.
• Confidentiality: Enabling next-generation systems that combine blockchains’ innate transparency with strong new confidentiality protections for sensitive data.
• Order-fairness for transactions: Supporting transaction sequencing in ways that are fair for end-users and prevent front-running and other attacks by bots and exploitative miners.
• Trust-minimization: Creating a highly trustworthy layer of support for smart contracts and other oracle-dependent systems by means of decentralization, strong anchoring in high-security blockchains, cryptographic techniques, and cryptoeconomic guarantees.
• Incentive-based (cryptoeconomic) security: Rigorously designing and robustly deploying mechanisms that ensure nodes in DONs have strong economic incentives to behave reliably and correctly, even in the face of well-resourced adversaries.
We present preliminary and ongoing innovations by the Chainlink community in each of these areas, providing a picture of the broadening and increasingly powerful capabilities planned for the Chainlink network.
A Research Summary has already been posted on this paper: Research Summary: Chainlink 2.0: Next Steps in the Evolution of Decentralized Oracle Networks
d-BAME: Distributed Blockchain-based Anonymous Mobile Electronic Voting
Authors: Ehab Zaghloul, Tongtong Li, and Jian Ren
Electronic voting (e-voting) presents a convenient and cost-effective alternative to current paper ballot-based voting. It provides many benefits such as increased voter turnout and accuracy in the decision-making process. While presenting many improvements, e-voting still faces serious security challenges that hinder its adoption, especially when designed to be run over mobile devices. In this paper, we propose a novel remote e-voting model for large-scale elections by proposing the participation of two conflicting parties to ensure election integrity and accountability. Our scheme can be implemented in IoT devices such as smartphones, which we believe can significantly increase voter turnout of the election process. Our proposed work is secure and preserves voter privacy through secure multi-party computations performed by parties of differing allegiances. It also leverages a blockchain running smart contracts as a publicly accessible and tamper-resistant bulletin board to permanently store votes and prevent double voting. In our security and privacy analysis, we show that our proposed scheme is secure against potential security threats and provides voter anonymity. We show orthogonality between universal verifiability and coercion- resistance in our proposed scheme, allowing an election to favor one over the other. Our performance analysis and smartphone simulation results show that the proposed scheme is practical for large-scale elections.
SCEW: Programmable BFT-Consensus with Smart Contracts for Client-Centric P2P Web Applications
Authors: Martijn Sauwens, Kristof Jannes, Bert Lagaisse, and Wouter Joosen
Collaborative web applications are becoming increasingly client-centric, with technologies such as WebRTC, WebWorkers and IndexedDB enabling a shift towards a decentralized peer-to-peer (P2P) model. Contemporary systems such as Automerge, Legion, OWebSync and Yjs provide fault tolerance and consistency by using Conflict-free Replicated Data Types for synchronization. These systems tolerate crash-faults, but lack resilience against arbitrary faults and malicious users, also known as Byzantine faults. Providing Byzantine fault tolerance (BFT) in web apps is non-trivial. Web apps are executed in web browsers on end user devices. The scarce compute resources and the interactive nature of collaborative web apps do require both a lightweight and low-latency solution, while still providing the Byzantine fault tolerance required by P2P systems to protect shared assets. Our work aims to fill this gap by introducing SCEW, a programming framework for client-centric P2P web apps that require BFT and interactive collaboration. SCEW achieves this by combining state-based Convergent Replicated Data Types (CvRDTs) and smart contracts. SCEW represents assets shared by peers as CvRDTs with atomic register semantics, that provide BFT through the use of BFT-consensus algorithms. SCEW employs smart contracts to define the life-cycle of these shared assets, shielding the application and its developers from the complexity of the CvRDT’s consensus protocol. Experimental results indicate that applications using SCEW can support P2P networks with 100 peers, even when Byzantine faults are present.
S-PoDL: A two-stage computational-efficient consensus mechanism for blockchain-enabled multi-access edge computing
Authors: Xiong Luo, Pan Yang, Weiping Wang, Yang Gao, and Manman Yuan
More recently, there has been a growing interest in the blockchain technique for emerging multi-access edge computing (MEC) applications in relation to security and privacy, considering the benefits of using it in edge computing. In some blockchain-enabled MEC using the best-known consensus algorithm proof-of-work (PoW), the computational efforts increase dramatically with the number of transactions, since a large amount of computational tasks should be conducted by miners with the limited computing resources in edge devices. Hence, improving the computational performance as an important but challenging issue in the design of blockchain system for MEC applications, has attracted intensive attention within last years. To further improve the performance of PoW algorithm, we present a novel implementation mechanism in this paper. Here, motivated by proof-of-deep-learning (PoDL) method in which the deep learning algorithm is used to maintain blockchain, through the design of a two-stage model to achieving computational tasks in PoDL-based blockchain systems, a novel computational-efficient consensus mechanism, named separate-proof-of-deep-learning (S-PoDL), is accordingly proposed. Thus, an energy-efficient blockchain-enabled MEC could be developed with our proposed S-PoDL, which arranges miners to carry out a two-stage-based computation on the basis of accounting_queue technique, while presenting the achieved models as proofs in MEC network. The comparative experiments are conducted between S-PoDL and PoDL, and the experimental results verify the feasibility and efficiency of our consensus mechanism S-PoDL for some blockchain-enabled MEC applications in relation to PoW-based cryptocurrencies, while effectively reducing computing burden of edge devices.
Trends in blockchain-based electronic voting systems
Authors: Michał Pawlak and AnetaPoniszewska-Marańda
Electronic voting systems face many challenges, including authentication, privacy, data integrity, transparency and verifiability. However, the developed over 10 years ago blockchain technology provides an out-of-the-box solution for many of those challenges. Despite that, some issues are still to be solved, like remote authentication, anonymity and end-to-end verifiability. For this reason, research on new and better blockchain-based systems is still ongoing. The main goal of this study is to highlight the current trends in this research and its eventual shortcomings. This was accomplished by conducting a Systematic Literature Review (SLR) (Kitchenham and Charters, 2007), which resulted in selecting 35 publications. The performed SLR allowed to define trends in utilized blockchain technologies, intended scenarios, testing methods, main benefits and challenges faced by various systems and the most used cryptographic solutions.
Security Issues with In-Vehicle Networks, and Enhanced Countermeasures Based on Blockchain
Authors: Narayan Khatri, Rakesh Shrestha, and Seung Yeob Nam
Modern vehicles are no longer simply mechanical devices. Connectivity between the vehicular network and the outside world has widened the security holes that hackers can use to exploit a vehicular network. Controller Area Network (CAN), FlexRay, and automotive Ethernet are popular protocols for in-vehicle networks (IVNs) and will stay in the industry for many more years. However, these protocols were not designed with security in mind. They have several vulnerabilities, such as lack of message authentication, lack of message encryption, and an ID-based arbitration mechanism for contention resolution. Adversaries can use these vulnerabilities to launch sophisticated attacks that may lead to loss of life and damage to property. Thus, the security of the vehicles should be handled carefully. In this paper, we investigate the security vulnerabilities with in-vehicle network protocols such as CAN, automotive Ethernet, and FlexRay. A comprehensive survey on security attacks launched against in-vehicle networks is presented along with countermeasures adopted by various researchers. Various algorithms have been proposed in the past for intrusion detection in IVNs. However, those approaches have several limitations that need special attention from the research community. Blockchain is a good approach to solving the existing security issues in IVNs, and we suggest a way to improve IVN security based on a hybrid blockchain.
Understanding the Benefit of Being Patient in Payment Channel Networks
Authors: Qianlan Bai, Yuedong Xu, and Xin Wang
Scaling blockchain efficiency is crucial to its widespread usage in which the payment channel is one of the most prominent approaches. With payment channels and the network they construct, two users can move some transactions off-chain in a predetermined duration to avoid expensive and time-consuming on-chain settlements. Existing work is devoted to designing high-throughput payment channel networks (PCNs) or efficient PCN routing policies to reduce the fee charged by intermediate nodes. In this paper, we investigate the PCN routing from a different perspective by answering whether the routing fee of transactions can be saved through being a bit more patient. The key idea is to reorder the processing sequence of atomic transactions, other than to handle each of them separately and immediately. We present two mechanisms, one is periodic transaction processing assisted by a PCN broker and the other is purely strategic waiting. In the former, all the incoming transactions in a short time interval are processed collectively. We formulate an optimization model to minimize their total routing fee and derive the optimal permutation of processing transactions as well as the routing policy for each of them. A Shapley value based scheme is presented to redistribute the benefit of reordering among the transactions efficiently and fairly. In the latter, we model the waiting time of a strategic transaction on a single payment channel as the first passage time problem in queueing theory when the transaction value is higher than the edge capacity upon its arrival. By capturing the capacity dynamics, we are able to calculate the recursive expression of waiting time distribution that is useful to gauge a user’s cost of patience. Experimental results manifest that our cost redistribution mechanism can effectively save routing fees for all the transactions, and the waiting time distribution coincides with the model well.
Digitization of Land Record Through Blockchain-based Consensus Algorithm
Authors: Amrendra Singh Yadav and Dharmender Singh Kushwaha
At present, real estate markets hold and contribute a fair share of the Gross Domestic Product (GDP) of any country. The real estate transactions generate revenue in stamp duties, which goes directly into the government kitty. However, this suffers from land document forgery and fraudulent activities due to a lack of an efficient, distributed, and completely digital system. This paper proposes a blockchain-based framework for digitizing property transactions that mitigate the risk of document forgery and other fraudulent activities. Over time, the amount of these transactions can become overwhelming, thus increasing the number of blocks. The proposed framework is based on blockchain technology to decentralize the complete ecosystem. The framework encompasses all major activities for property transactions. The framework uses the InterPlanetary File System (IPFS) that is a Peer-to-Peer (P2P) swarm network, to integrate different region registry offices in the state/country seamlessly. In order to make it secure, a consensus algorithm is proposed that reduces overhead transmissions for multicasting nodes by about 50%. The message exchange communication overhead also reduces by 54.86%. The time taken for the consensus algorithm is around 53.7% lesser than the Proof-of-Work mechanism in which all nodes participate in consensus and 10% lesser than the existing load-based approach.
A Big Data Analysis of the Ethereum Network: from Blockchain to Google Trends
Authors: Dorsa Mohammadi Arezooji
First, a big data analysis of the transactions and smart contracts made on the Ethereum blockchain is performed, revealing interesting trends in motion. Next, these trends are compared with the public’s interest in Ether and Bitcoin, measured by the volume of online searches. An analysis of the crypto prices and search trends suggests the existence of big players (and not the regular users), manipulating the market after a drop in prices. Lastly, a cross-correlation study of crypto prices and search trends reveals the pairs providing more accurate and timely predictions of Ether prices.
Blockchain and smart contract for IoT enabled smart agriculture
Authors: Tahmid Hasan Pranto, Abdulla All Noman, Atik Mahmud, and AKM Bahalul Haque
The agricultural sector is still lagging behind from all other sectors in terms of using the newest technologies. For production, the latest machines are being introduced and adopted. However, pre-harvest and post-harvest processing are still done by following traditional methodologies while tracing, storing, and publishing agricultural data. As a result, farmers are not getting deserved payment, consumers are not getting enough information before buying their product, and intermediate person/processors are increasing retail prices. Using blockchain, smart contracts, and IoT devices, we can fully automate the process while establishing absolute trust among all these parties. In this research, we explored the different aspects of using blockchain and smart contracts with the integration of IoT devices in pre-harvesting and post-harvesting segments of agriculture. We proposed a system that uses blockchain as the backbone while IoT devices collect data from the field level, and smart contracts regulate the interaction among all these contributing parties. The system implementation has been shown in diagrams and with proper explanations. Gas costs of every operation have also been attached for a better understanding of the costs. We also analyzed the system in terms of challenges and advantages. The overall impact of this research was to show the immutable, available, transparent, and robustly secure characteristics of blockchain in the field of agriculture while also emphasizing the vigorous mechanism that the collaboration of blockchain, smart contract, and IoT presents.