Blockchain Protocol Research Articles

Transparent and Tamper-Proof Event Ordering in the Internet of Things Platforms

Today, the audit and diagnosis of the causal relationships between the events in a trigger-action-based event chain (e.g., why is a light turned on in a smart home?) in the Internet of Things (IoT) platforms are untrustworthy and unreliable. The current IoT platforms lack techniques for transparent and tamper-proof ordering of events due to their device-centric logging mechanism. In this article, we develop a framework that facilitates tamper-proof transparency and event order in an IoT platform by proposing a Blockchain protocol and adopting the vector clock system, both tailored for the resource-constrained heterogeneous IoT devices, respectively. To cope with the unsuited storage (e.g., ledger) and computing power (e.g., proof-of-work puzzle) requirements of the Blockchain in the commercial off-the-shelf IoT devices, we propose a partial consistent cut protocol and engineer a modular arithmetic-based lightweight proof of work puzzle, respectively. To the best of our knowledge, this is the first Blockchain designed for resource-constrained heterogeneous IoT platforms. Our event ordering protocol based on the vector clock system is also novel for the IoT platforms. We implement our framework using an IoT gateway and 30 IoT devices. We experiment with ten concurrent trigger-action-based event chains while each chain involves 20 devices, and each device participates in five different chains. The results show that our framework may order these events in 2.5 s while consuming approximately 140 mJ of energy per device. The results, hence, demonstrate the proposed platform as a practical choice for many IoT applications, such as smart home, traffic monitoring, and crime investigation.

How Should We Regulate Cryptocurrencies via Consensus?: A Strategic Framework for Optimal Legal Transaction Throughput

Permissionless blockchain consensus protocols have been leveraged for defining decentralized economies for the (commercial or private) trade of virtual and physical assets, using cryptocurrencies. In most instances, the assets being traded are regulated , which mandates that the legal right to their trade and their trade value are determined by the governmental regulator of the jurisdiction in which the trade occurs. Unfortunately, existing blockchains do not formalize proposal of legal cryptocurrency transactions, as part of the execution of their respective consensus protocols, resulting in illegal activities in the associated crypto-economies. In this contribution, unlike existing non-consensus solutions, which are prone to be more compute-time and audit-time intensive, we present a novel regulatory framework for blockchain protocols, for ensuring legal transaction confirmation as part of the blockchain consensus. As per our regulatory framework, we derive, through a stochastic game analysis, block proposal strategies under which legal transaction throughput supersedes throughput of traditional transactions, which are, in the worst case, an indifferentiable mix of legal and illegal transactions. Finally, we show that when a majority of the consensus protocol participants are licensed by the regulator to propose legal transactions, there exists a fair consensus execution policy to maximize the legal transaction throughput in the blockchain network.

Resilience of Hybrid Casper Under Varying Values of Parameters

Hybrid Casper is the new Ethereum blockchain protocol that uses both Proof of Work and Proof of Stake to reach a consensus between nodes. Here, we analyze the protocol using PRISM+ , an extension of the probabilistic model checker PRISM with primitives for expressing blockchain data types. First, we extend PRISM+ to include data types and operations for modeling and analyzing Proof of Stake based consensus protocols. Then, we model Hybrid Casper in PRISM+ as a parallel composition of stochastic processes, thus precisely describing the behavior of the protocol and highlighting its corner cases. PRISM+ is therefore used to rapidly and automatically analyze the resilience of Hybrid Casper when tuning, up or down, several basic parameters of the protocol, such as the rates of creating blocks, and the strategies for determining penalties. Finally, we study the robustness of Hybrid Casper to two well-known attacks: the Eclipse attack and the majority attack.

Quantum Multi-Solution Bernoulli Search with Applications to Bitcoin's Post-Quantum Security

A proof of work (PoW) is an important cryptographic construct enabling a party to convince others that they invested some effort in solving a computational task. Arguably, its main impact has been in the setting of cryptocurrencies such as Bitcoin and its underlying blockchain protocol, which received significant attention in recent years due to its potential for various applications as well as for solving fundamental distributed computing questions in novel threat models. PoWs enable the linking of blocks in the blockchain data structure and thus the problem of interest is the feasibility of obtaining a sequence (chain) of such proofs. In this work, we examine the hardness of finding such chain of PoWs against quantum strategies. We prove that the chain of PoWs problem reduces to a problem we call multi-solution Bernoulli search, for which we establish its quantum query complexity. Effectively, this is an extension of a threshold direct product theorem to an average-case unstructured search problem. Our proof, adding to active recent efforts, simplifies and generalizes the recording technique of Zhandry (Crypto'19). As an application, we revisit the formal treatment of security of the core of the Bitcoin consensus protocol, the Bitcoin backbone (Eurocrypt'15), against quantum adversaries, while honest parties are classical and show that protocol's security holds under a quantum analogue of the classical “honest majority'' assumption. Our analysis indicates that the security of Bitcoin backbone is guaranteed provided the number of adversarial quantum queries is bounded so that each quantum query is worth O(p−1/2) classical ones, where p is the success probability of a single classical query to the protocol's underlying hash function. Somewhat surprisingly, the wait time for safe settlement in the case of quantum adversaries matches the safe settlement time in the classical case.

Sharding-Based Proof-of-Stake Blockchain Protocols: Key Components & Probabilistic Security Analysis

Blockchain technology has been gaining great interest from a variety of sectors including healthcare, supply chain, and cryptocurrencies. However, Blockchain suffers from a limited ability to scale (i.e., low throughput and high latency). Several solutions have been proposed to tackle this. In particular, sharding has proved to be one of the most promising solutions to Blockchain's scalability issue. Sharding can be divided into two major categories: (1) Sharding-based Proof-of-Work (PoW) Blockchain protocols, and (2) Sharding-based Proof-of-Stake (PoS) Blockchain protocols. The two categories achieve good performances (i.e., good throughput with a reasonable latency), but raise security issues. This article focuses on the second category. In this paper, we start by introducing the key components of sharding-based PoS Blockchain protocols. We then briefly introduce two consensus mechanisms, namely PoS and practical Byzantine Fault Tolerance (pBFT), and discuss their use and limitations in the context of sharding-based Blockchain protocols. Next, we provide a probabilistic model to analyze the security of these protocols. More specifically, we compute the probability of committing a faulty block and measure the security by computing the number of years to fail. We achieve a number of years to fail of approximately 4000 in a network of 4000 nodes, 10 shards, and a shard resiliency of 33%.

Benzene: Scaling Blockchain With Cooperation-Based Sharding

Sharding has been considered as a prominent approach to enhance the limited performance of blockchain. However, most sharding systems leverage a non-cooperative design, which lowers the fault tolerance resilience due to the decreased mining power as the consensus execution is limited to each separated shard. To this end, we present Benzene, a novel sharding system that enhances the performance by cooperation-based sharding while defending the per-shard security. First, we establish a double-chain architecture for function decoupling. This architecture separates transaction-recording functions from consensus-execution functions, thereby enabling the cross-shard cooperation during consensus execution while preserving the concurrency nature of sharding. Second, we design a cross-shard block verification mechanism leveraging Trusted Execution Environment (TEE), via which miners can verify blocks from other shards during the cooperation process with the minimized overheads. Finally, we design a voting-based consensus protocol for cross-shard cooperation. Transactions in each shard are confirmed by all shards that simultaneously cast votes, consequently achieving an enhanced fault tolerance and lowering the confirmation latency. We implement Benzene and conduct both prototype experiments and large-scale simulations to evaluate the performance of Benzene. Results show that Benzene achieves superior performance than existing sharding/non-sharding blockchain protocols. In particular, Benzene achieves a linearly-improved throughput with the increased number of shards (e.g., 32,370 transactions per second with 50 shards) and maintains a lower confirmation latency than Bitcoin (with more than 50 shards). Meanwhile, Benzene maintains a fixed fault tolerance at 1/3 even with the increased number of shards.

A Flexible Sharding Blockchain Protocol Based on Cross-Shard Byzantine Fault Tolerance

Sharding technology is crucial to achieve decentralization, scalability, and security simultaneously. However, existing sharding blockchain schemes suffer from high cross-shard transaction processing latency, low parallelism, incomplete cross-shard views of shard members, centralized reconfiguration, high overhead of randomness generation, and lack of formalized protocol design and security proofs. This paper proposes a flexible sharding (FS) blockchain protocol. First, a cross-shard Byzantine fault tolerance (CSBFT) protocol is designed to cut down confirmation delays when processing cross-shard transactions. Second, we utilize multiple parallel CSBFT where each node acts not only as a leader but also as multiple ordinary members to break through the performance bottleneck caused by a leader’s bandwidth and computing power, improving the system parallelism. Third, a cross-shard transaction censorship attack is proposed, and a cross-shard view-change mechanism is designed to defend against it. Fourth, a secure and truly decentralized shard reconfiguration method combining proof-of-work, proof-of-possession, and intra-shard BFT is designed. Fifth, we utilize a formal protocol design method and give strict security proof for each protocol. Finally, we evaluate FS from both theoretical and practical perspectives. FS is proven to have lower communication and computation complexity and achieve considerable performance.

A Tractable Probabilistic Approach to Analyze Sybil Attacks in Sharding-Based Blockchain Protocols

Blockchain like Bitcoin and Ethereum suffer from scalability issues. Sharding is one of the most promising and leading solutions to scale blockchain. The basic idea behind sharding is to divide the blockchain network into multiple committees, where each processing a separate set of transactions, rather than the entire network processes all transactions. In this paper, we propose a probabilistic approach to analyze the security of sharding-based blockchain protocols. Based on this approach, we investigate the threat of Sybil attacks in these protocols. The key contribution of our paper is a tractable probabilistic approach to accurately compute the failure probability that at least one committee fails and ultimately compute the probability of a successful attack. To show the effectiveness of our approach, we conduct a numerical and comparative analysis of the proposed approach with existing approaches.

Hedged Mutual Fund Blockchain Protocol: High Water Marks During Low Market Prices

Hedged Mutual Fund Blockchain Protocol: High Water Marks During Low Market Prices

Metaverse: Essence and Military Application Value

Global trends in digitalization and the consequences of the pandemic stirred up public interest in the metaverse space, which completely lacked the restrictions imposed by the governments of national states. Projects such as Second Life, Decentraland, The Sandbox, and others promote a new form of human existence and communication as an alternative to meeting basic human needs for live, contact, and freedom of movement. Leading technology companies are included in the development of metaverse of various purposes. It is assumed that the development of immersive technologies will make the presence in the metaverse approximate in feeling to real life and most of the social activity associated primarily with work and entertainment will flow into its virtual space. It is likely that the developers of the metaverse will agree on the use of a single blockchain protocol (a set of rules and actions in the network) that ensures uninterrupted data transfer, their complete safety and transparency. This, in turn, will lead to the emergence of unified digital property and its distribution in the Internet space Web 3.0 and 4.0. The basic principles of metaverse construction are used by the military departments of leading countries to organize a network in which the interaction of types and types of troops is tested through appropriate simulators, taking into account the implementation of the skills of military specialists connected to it. At the same time, the steady interest of the military in game simulations has been preserved since the mid-1980s. The potential of such a metaverse of virtual worlds has already been realized in military activities in the preparation of calculations of weapons, military and special equipment. The capabilities of this technology for military affairs go beyond the exclusively educational resource and are able to change the content of future military conflicts. Extended reality (XR) interfaces, which will be improved during the creation of metaverse, will subsequently become an integral part of armed struggle.

ARCHITECTURE OF DECENTRALIZED APPLICATIONS AS PART OF THE DEFI ECOSYSTEM

The functional features of cryptographic technologies in combination with decentralized data registries gave impetus to the development of the segment of decentralized financial assets. Evolutionarily, special decentralized applications were created that ensure the correct operation of the entire DeFi ecosystem. This work is devoted to the study of decentralized applications, since this is the main link of the market of decentralized finance, which provides an interface for the interaction of market subjects. In our work, we study the architecture of decentralized applications in particular detail. In the course of the work, we analyzed the dynamics of the creation of new decentralized applications on the main networks of the ecosystem. We found that most modern applications were created between 2017 and 2019, but new and newer use cases for decentralized applications are constantly emerging. We also identified and outlined the main categories of decentralized application architecture components. We added to the external parts of the architectural components: application developer, blockchain developer, application user, contract user, token user, consensus provider; and internal architectural components: client, smart contract, token, blockchain platform, other platforms. Several examples of the operation of blockchain protocols and the principles of transaction confirmation are in work. We created a detailed diagram of the interaction of all parts of the architecture, as well as subjects participating in the work of applications. We also explained the difference between tokens and coins, as well as accompanying conclusions regarding the practical side of the difference of decentralized assets. We also highlighted several features of the functioning of parts of the architecture of decentralized applications, in particular, management methods and the organization of interactions between different protocols in the middle of the DeFi ecosystem. We have also made appropriate conclusions on the work.

Optimal mining in proof-of-work blockchain protocols

This paper examines the economic mechanism of cryptocurrency mining. By presenting a profit function, a maximization equilibrium is obtained. The model provides a formal approach to the demand for hashing power as a function of revenues, mining costs and the number of miners. We consider how the equilibrium is affected by passive miners. We use these results to introduce a formulation of the price elasticity of the demand for hashing power with respect to the cost of energy. The model is simulated using Reinforcement Learning algorithms that arrive to similar equilibrium results. The article concludes with implications of the model for policymaking.

Distributed Authentication Using Blockchain for Protected Communication in Cloud Based IoT Platform

Purpose: The technology has improvised to control the devices from the remote location using the IoT framework. To improvise the storage efficiency of the technology the IoT is integrated with the cloud network. When the huge size of the data is generated this cloud server hosts the space for the big data. But the secure exchange of the data between the IoT data is not efficient to protect the confidentiality of the data. The existing security systems are either concentrating on the authentication or secure validation. Hence there is a demand for the lightweight, less complex, and strong secure framework. Design/ Methodology/Approach: The authentication phase of the proposed framework is designed using distributed block chain protocol to authenticate multiple users in the cloud environment. The SALSA20 encryption algorithm which augments the strength of the data security. The protected key exchange is done using the ReDH algorithm. Indexing is done using the hash algorithm to obtain the accuracy in the search results and to minimize the encrypting and decrypting time. Findings/ Results: The proposed distributed block chain authentication framework is proved to be efficient with less encrypting and decrypting periods of about 0.25ms and 0.2ms respectively. 97.5% of the storage efficiency proves this model to be suitable for the cloud application. Originality/Value: The proposed model has a dedicated database for the registration for the users and IoT devices which is used to validate the authentication of the system. The encryption is done using the SALSA20 algorithm and sensitivity level prediction process to measure the sensitivity score. Paper Type: Experimental Research

Accounting and auditing with blockchain technology and artificial Intelligence: A literature review

This paper surveys the published work on how blockchain technology will impact accounting in general, but AI-enabled auditing specifically. The purpose is to investigate how blockchain technology can improve transparency and trust in accounting practice and how professionals can use blockchain data to improve decision-making, based on the qualities of immutability, append-only, shared, verified, and agreed-upon (i.e., consensus-driven) blockchain data. The multi-party validation of blockchain protocols adds real-time trusted data for the AI systems used by auditors to improve assurance and efficiency. This review summarizes four themes emerging from the literature focusing on how blockchain technology has changed record-keeping in accounting: event approach to accounting; real-time accounting; triple entry-accounting and continuous auditing. The research interprets the findings using agency theory and stakeholder theory to advance how using blockchain to mitigate information asymmetry and improve stakeholder collaborations is understood. The investigation also summarizes the challenges and clarifies organizations’ reasons to be cautious about adopting blockchain. Lastly, the study suggests that future researchers use this study in two ways that enrich blockchain literature: first, to apply the themes and answer the questions identified within this review to improve the business methods of practitioners and policymakers; and second, to encourage stakeholders such as practitioners, system designers/developers, and policymakers to collaborate in designing blockchain ecosystems that suit accounting and auditing as they transform digitally.

Evolutionary dynamics of sustainable blockchains

The energy sustainability of blockchains, whose consensus protocol rests on the Proof-of-Work, nourishes a heated debate. The underlying issue lies in a highly energy-consuming process, defined as mining, required to validate crypto-asset transactions. Mining is the process of solving a cryptographic puzzle, incentivized by the possibility of gaining a reward. The higher the number of users performing mining, i.e. miners, the higher the overall electricity consumption of a blockchain. For that reason, mining constitutes a negative environmental externality. Here, we study whether miners’ interests can meet the collective need to curb energy consumption. To this end, we introduce the Crypto-Asset Game, namely a model based on the framework of Evolutionary Game Theory devised for studying the dynamics of a population whose agents can play as crypto-asset users or as miners. The proposed model, studied via numerical simulations, reveals a rich spectrum of possible steady states. Interestingly, by setting the miners’ reward in the function of the population size, agents reach a strategy profile that optimizes global energy consumption. To conclude, can a Proof-of-Work-based blockchain become energetically sustainable? Our results suggest that blockchain protocol parameters could have a relevant role in the global energy consumption of this technology.

A probabilistic temporal epistemic logic: Strong completeness

Abstract The paper offers a formalization of reasoning about distributed multi-agent systems. The presented propositional probabilistic temporal epistemic logic $\textbf {PTEL}$ is developed in full detail: syntax, semantics, soundness and strong completeness theorems. As an example, we prove consistency of the blockchain protocol with respect to the given set of axioms expressed in the formal language of the logic. We explain how to extend $\textbf {PTEL}$ to axiomatize the corresponding first-order logic.

Blockchain-Enabled Approach for Big Data Processing in Edge Computing

The integration of blockchain with edge computing technology has emerged as a popular topic in recent years. Edge computing offers many advantages to IoT data computing by reducing the bandwidth in the cloud, whereas blockchain offers a promising solution to the data integrity issues of dynamic edge nodes. There is considerable technological mismatch, however, when employing a blockchain protocol for edge computing. Standard edge nodes usually deal with big data and require constant data exchange over time, whereas traditional blockchains prevent the storage of big data in a distributed network. This study presents a novel blockchain architecture called Recordchain, which is fully adapted to the edge computing environment. The innovative feature of Recordchain is its ability to locate actual data separately while providing security, scalability, and performance, thus addressing the storage utilization issues related to big data. The efficiency and performance of the proposed architecture is further demonstrated experimentally.

A Reputation-Based Mechanism for Transaction Processing in Blockchain Systems

Blockchain protocols require nodes to verify all received transactions before forwarding them. However, massive spam transactions cause the participants in blockchain systems to consume many resources in verifying and propagating transactions. This paper proposes a reputation-based mechanism to increase the efficiency of processing transactions by considering the reputations of the sending nodes. Reputations are in turn adjusted based on the quality of transaction processing. Our proposed reputation-based mechanism offers three main contributions. First, we modify the verification strategy so that nodes set a probability of verifying a received transaction considering the likelihood of it being spam: transactions from a node with a low reputation have a high probability of being verified. Second, we optimize the transaction forwarding protocol to reduce propagation delay by prioritizing forwarding transactions to reputable receivers. Third, we design a data request protocol that provides alternative data exchange methods for nodes with different reputations. A series of simulations demonstrate the performance of our reputation-based mechanism.

A Blockchain Protocol for Authenticating Space Communications between Satellites Constellations

Blockchain has found many applications, apart from Bitcoin, in different fields and it has the potential to be very useful in the satellite communications and space industries. Decentralized and secure protocols for processing and manipulating space transactions of satellite swarms in the form of Space Digital Tokens (SDT) can be built using blockchain technology. Tokenizing space transactions using SDTs will open the door to different new blockchain-based solutions for the advancement of constellation-based satellite communications in the space industry. Developing blockchain solutions using smart contracts could be used in securely authenticating various P2P satellite communications and transactions within/between satellite swarms. To manage and secure these transactions, using the proposed SDT concept, this paper suggested a blockchain-based protocol called Proof of Space Transactions (PoST). This protocol was adopted to manage and authenticate the transactions of satellite constellations in a P2P connection. The PoST protocol was prototyped using the Ethereum blockchain and experimented with to evaluate its performance using four metrics: read latency, read throughput, transaction latency, and transaction throughput. The simulation results clarified the efficiency of the proposed PoST protocol in processing and verifying satellite transactions in a short time according to read and transaction latency results. Moreover, the security results showed that the proposed PoST protocol is secure and efficient in verifying satellite transactions according to true positive rate (TPR), true negative rate (TNR), and accuracy metrics. These findings may shape a real attempt to develop a new generation of Blockchain-based satellite constellation systems.

Scheduling and Securing Drone Charging System Using Particle Swarm Optimization and Blockchain Technology

Unmanned aerial vehicles (UAVs) have emerged as a powerful technology for introducing untraditional solutions to many challenges in non-military fields and industrial applications in the next few years. However, the limitations of a drone’s battery and the available optimal charging techniques represent a significant challenge in using UAVs on a large scale. This problem means UAVs are unable to fly for a long time; hence, drones’ services fail dramatically. Due to this challenge, optimizing the scheduling of drone charging may be an unusual solution to drones’ battery problems. Moreover, authenticating drones and verifying their charging transactions with charging stations is an essential associated problem. This paper proposes a scheduling and secure drone charging system in response to these challenges. The proposed system was simulated on a generated dataset consisting of 300 drones and 50 charging station points to evaluate its performance. The optimization of the proposed scheduling methodology was based on the particle swarm optimization (PSO) algorithm and game theory-based auction model. In addition, authenticating and verifying drone charging transactions were executed using a proposed blockchain protocol. The optimization and scheduling results showed the PSO algorithm’s efficiency in optimizing drone routes and preventing drone collisions during charging flights with low error rates with an MAE = 0.0017 and an MSE = 0.0159. Moreover, the investigation to authenticate and verify the drone charging transactions showed the efficiency of the proposed blockchain protocol while simulating the proposed system on the Ethereum platform. The obtained results clarified the efficiency of the proposed blockchain protocol in executing drone charging transactions within a short time and low latency within an average of 0.34 s based on blockchain performance metrics. Moreover, the proposed scheduling methodology achieved a 96.8% success rate of drone charging cases, while only 3.2% of drones failed to charge after three scheduling rounds.