As blockchain technology becomes trendy in different industries, its application in banking industry is of utmost importance too. Banks in different countries attempt to utilize this technology in wide variety of banking functions. By considering that there are millions of migrants living in far distance than their own countries. The regularly send money to their families. However, current banking and money transfer services are costly and timely, which particularly affects those who send low amount of money in weekly or monthly basis. Blockchain technology with a particular emphasis on the development of cryptocurrencies related to remittance transactions become a solution for both banks and people. This research uses MCDM with an inclusion of AHP and TOPSIS methods to select the most ideal cryptocurrency to solve the remittance transaction problem. Based on the three criteria, namely underlying technology, recognition, and external impact (cost), it is found that Ripple (XRP) is considered the most optimal cryptocurrency by experts who are knowledgeable in both conventional banking process and blockchain technology. Sensitivity analysis is also performed to ensure the validity of the finding, and Ripple (XRP) remains the optimal cryptocurrency in remittance transaction.
This study applies reinforcement learning (RL) from the AI machine learning field to derive an optimal Bitcoin-like blockchain mining strategy. A salient feature of the RL learning framework is that an optimal (or near-optimal) strategy can be obtained without knowing the details of the blockchain network model. Previously, the most profitable mining strategy was believed to be honest mining encoded in the default blockchain protocol. It was shown later that it is possible to gain more mining rewards by deviating from honest mining. In particular, the mining problem can be formulated as a Markov Decision Process (MDP) which can be solved to give the optimal mining strategy. However, solving the mining MDP requires knowing the values of various parameters that characterize the blockchain network model. In real blockchain networks, these parameter values are not easy to obtain and may change over time. This hinders the use of the MDP model-based solution. In this study, we employ RL to dynamically learn a mining strategy with performance approaching that of the optimal mining strategy. Since the mining MDP problem has a nonlinear objective function (rather than linear functions of standard MDP problems), we design a new multidimensional RL algorithm to solve the problem. Experimental results indicate that, without knowing the parameter values of the mining MDP model, our multidimensional RL mining algorithm can still achieve optimal performance over time-varying blockchain networks.
Yongjie Ye, Jingjing Zhang, Weigang Wu, Xiapu Luo · 5 authors
The payment channel, which allows two parties to perform micropayments without involving the blockchain, has become a promising proposal to improve the scalability of decentralized ledgers such as Bitcoin and Ethereum. Payment channels have been extended to the payment network, through which users can utilize existing channels as intermediary links to route coins to others. However, routing payments through multiple channels bears nontrivial overheads. It requires every intermediary channel to lock a portion of its available capacity until the payment is settled. This may lead to deadlock in a concurrent situation. The intermediary nodes in a payment path may also charge fees for routing a payment. The longer the routing path, the more serious the above problems. In this paper, we design and develop a novel off-chain system to shorten the routing path for the payment network. In particular, we propose the channel hub, which is an extension of the payment hub, to allows transferring coins directly from one payment channel to another within the same hub. That is, the channel hub can be viewed as a shortcut device for the underlying payment network. We design a new protocol named Boros to perform secure off-chain cross-channel transfers through the channel hub. We not only present the security definition of the Boros protocol formally but also prove its security using the UC-framework. To demonstrate the feasibility of the Boros protocol, we develop a proof-of-concept prototype running on the Ethereum. Our evaluation shows that our system can effectively shorten the off-chain routing path.
Spain is a country where the nationalist cleavage has a fundamental importance to understand the party systems and the dynamics of electoral competition in some Autonomous Communities. This article analyzes the electoral bases of the main regionalist parties in Spain and, specifically, it focuses on the electoral bases of Canary Coalition (CC). Despite its importance at the regional level, this party has received little attention by the academic literature. This article confirms the idea that CC is a party able to mobilize an electorate whose preferences are for a more decentralized territorial organization than the current one. However, the key finding is that, unlike what happens with the main regionalist parties in Spain, the identity associated with the Autonomous Community is not an explanatory factor of the vote for CC, what shows that the Canarian identity is not politically activated.
Purpose The purpose of this paper is to examine the operational and regulatory positions of the employment of Blockchain in the insurance industry. Blockchain technology has attracted wide interest from various stakeholders. Many theorists are predicting that this technology will disrupt financial services, including insurance. As stated that the development of blockchain is dependent on regulatory acceptance of this technology, it is essential to establish the current state of play with regard to the application and use of blockchain from a commercial and regulatory standpoints. Design/methodology/approach This review encompasses a number of approaches to view the current status of Blockchain applications. From a commercial approach, this research lists the current applications of blockchain within the insurance industry. From a regulatory point of view, the current positions of the EU and national regulatory bodies are enquired upon to establish how they are examining FinTech and Blockchain technologies within their regulatory processes. Findings This review illustrates a number of Blockchain applications in situ from a commercial point of view. From a regulatory setting and following a call from international and EU levels, it appears that various regulatory bodies have begun the process of formulating testing processes for FinTech applications. There are two predominant types in operation, while others are forming points of contact for advice for FinTechs and a small amount who have not begun the process at all. Research limitations/implications This review illustrates the current state of play of blockchain in insurance from a commercial and regulatory point of view. While this has been observational, this review pulls together information from various sources to encapsulate the regulatory positioning of evaluating FinTech and Blockchain technologies for academia, regulatory and industry audiences. Originality/value This review offers a central resource of information with regard to the current state of blockchain technologies in operation and regulatory approaches to this and other FinTech developments.
With blockchain technology, information is recorded in a permanent distributed ledger that is maintained by multiple computers in a peer-to-peer network. There is no central authority that can alter records or change network consensus rules. Such technology could be utilized for voting, title transfers, issuance of company shares, document notarization, but currently, the most popular use-case are virtual currencies. An interesting feature that some virtual currencies have is a multisignature (multisig) protocol that requires the electronic signatures from more than one private key to initiate a transfer of funds. Raw data of a multisig transaction may be recognized as an arbitral award under the New York Convention, where the law of England is the lex arbitri and parties have opted-out of a reasoned award.
Randpay is a technology developed in Emercoin for blockchain micropayments that can be more effective in some scenarios than the Lightning Network as we show in the paper. The protocol is based on the concept of Ronald L. Rivest and published in the paper "Electronic Lottery Tickets as Micropayments" (1997). The "lottery ticket" was designed for centralized systems where a trusted third party is required to provide payments, and in some scenarios is also a lottery facilitator. The existing blockchain protocol cannot accommodate peer-to-peer "lottery" micropayments at least without the need to create payment channels, which is analysed in the paper. Therefore, the implementation required the development of an update to the blockchain core. In the result, RandpayUTXO was introduced - infinitely spendable zero output that requires the payee's signature to be published in the blockchain. Randpay is considered to be the first blockchain protocol to require the payee to sign the transaction by their private key. This is a significant feature to improve not only microtransactions but also extend the use of the blockchain for legal deeds that require a payee's consent to be recognised in legal applications. The second important innovation of this research is the implementation of Blum's "coin flipping by telephone" problem to design a "lottery ticket" that does not require any third party to facilitate the lottery. The paper offers an API description, an analysis of the mathematical model, and proof of how "lottery" can be beneficial. There is also an attack analysis and overview of existing solutions.
Hyperledger Fabric is a distributed operating system for permissioned blockchains hosted by the Linux Foundation. It is the first truly extensible blockchain system for running distributed applications at enterprise grade scale. To achieve this, Hyperledger Fabric introduces a novel execute-order-validate blockchain architecture, allowing parallelization of transaction execution and validation. However, this raises the need for transaction isolation. Today transaction isolation is attained by locking the entire state database during simulation of transactions and database updates. This lock is one of the major performance bottlenecks as observed by previous work. This work presents a new lock-free approach for providing transaction isolation. It harnesses the already existing versioning of key-value pairs in the database, used primarily for a read-write conflict detection during the validation phase, to create a version-based snapshot isolation. We further implement and evaluate our new approach. We show that our solution outperforms the current implementation by 8.1x and that it is comparable to the optimal solution where no isolation mechanism is applied.
We present Solythesis, a source to source Solidity compiler which takes a smart contract code and a user specified invariant as the input and produces an instrumented contract that rejects all transactions that violate the invariant. The design of Solythesis is driven by our observation that the consensus protocol and the storage layer are the primary and the secondary performance bottlenecks of Ethereum, respectively. Solythesis operates with our novel delta update and delta check techniques to minimize the overhead caused by the instrumented storage access statements. Our experimental results validate our hypothesis that the overhead of runtime validation, which is often too expensive for other domains, is in fact negligible for smart contracts. The CPU overhead of Solythesis is only 0.12% on average for our 23 benchmark contracts.
Proof of Stake (PoS) is a burgeoning Sybil resistance mechanism that aims to have a digital asset ("token") serve as security collateral in crypto networks. However, PoS has so far eluded a comprehensive threat model that encompasses both Byzantine attacks from distributed systems and financial attacks that arise from the dual usage of the token as a means of payment and a Sybil resistance mechanism. In particular, the existence of derivatives markets makes malicious coordination among validators easier to execute than in Proof of Work systems. We demonstrate that it is also possible for on-chain lending smart contracts to cannibalize network security in PoS systems. When the yield provided by these contracts is more attractive than the inflation rate provided from staking, stakers will tend to remove their staked tokens and lend them out, thus reducing network security. In this paper, we provide a simple stochastic model that describes how rational validators with varying risk preferences react to changes in staking and lending returns. For a particular configuration of this model, we provide a formal proof of a phase transition between equilibria in which tokens are predominantly staked and those in which they are predominantly lent. We further validate this emergent adversarial behavior (e.g. reduced staked token supply) with agent-based simulations that sample transitions under more realistic conditions. Our results illustrate that rational, non-adversarial actors can dramatically reduce PoS network security if block rewards are not calibrated appropriately above the expected yields of on-chain lending.
Muhammad Anwar Hussain, Muhammad Shafie Abd Latiff, Syed Hamid Hussain Madni, Raja Zuraidah Raja Mohd Rasi · 5 authors
Blockchain, Bitcoin's core technology, and spinal cord have received enthusiastic attention since the last couple of decades. The Blockchain serves as a paradigm for distributed and unchangeable computations for bitcoins and cryptocurrencies. The key features behind this technology are to create a reliable, secure, transparent, decentralized, and reliable autonomous ecosystem. It is useful for a variety of applications, especially for legacy devices, resources, and infrastructure. In this article, we presented a technical overview, its application, and the challenges associated with blockchain technology and cryptocurrencies. This study aims to provide a ground-breaking overview and future research direction and promising importance of Blockchain.
Open access
Blockchain Technology Applications and Security
IoT and Edge/Fog Computing
Advanced Steganography and Watermarking Techniques
With the arrival of the Internet of Things (IoT) era and the rise of Big Data, cloud computing, and similar technologies, data resources are becoming increasingly valuable. Organizations and users can perform all kinds of processing and analysis on the basis of massive IoT data, thus adding to their value. However, this is based on data-sharing transactions, and most existing work focuses on one aspect of data transactions, such as convenience, privacy protection, and auditing. In this paper, a data-sharing-transaction application based on blockchain technology is proposed, which comprehensively considers various types of performance, provides an efficient consistency mechanism, improves transaction verification, realizes high-performance concurrency, and has tamperproof functions. Experiments were designed to analyze the functions and storage of the proposed system.
Teknologi Blockchain atau yang dikenal sebagai distributed ledger merupakan sistem pencatatan yang tersebar luas di jaringan. Blockchain menjadi salah satu teknologi yang memiliki sistem keamanan yang sulit diretas karena setiap jaringan memiliki enkripsi yang berlapis. Selain faktor keamanan, teknologi Blockchain juga memberikan manfaat lain seperti membuat proses transasksi menjadi lebih efisien dengan cara menghapus peran penghubung (middleman). Selain itu, Blockhain juga mampu diimplementasikan di berbagai industri, termasuk Usaha Mikro, Kecil dan Menengah (UMKM). Eksistensi UMKM di Indonesia sangat penting guna membantu penyerapan tenaga kerja, sarana distribusi perekonomian bagi masyarakat dan membantu penerimaan devisa negara. Mengingat pentingnya peran UMKM bagi Indonesia, maka Edukasi Blockchain bagi pelaku UMKM perlu dilakukan sehingga keberlangsungan dan perkembangan bisnis UMKM di Indonesia dapat terus ditingkatkan.Kata kunci : Blockchain, UMKM
The continually rising demand for wireless services and applications in the era of Internet of things (IoT) and artificial intelligence (AI) presents a significant number of unprecedented challenges to existing network structures. To meet the rapid growth need of mobile data services, blockchain radio access network (B-RAN) has emerged as a decentralized, trustworthy radio access paradigm spurred by blockchain technologies. However, many characteristics of B-RAN remain unclear and hard to characterize. In this study, we develop an analytical framework to model B-RAN and provide some basic fundamental analysis. Starting from block generation, we establish a queuing model based on a time-homogeneous Markov chain. From the queuing model, we evaluate the performance of B-RAN with respect to latency and security considerations. By connecting latency and security, we uncover a more comprehensive picture of the achievable performance of B-RAN. Further, we present experimental results via an innovative prototype and validate the proposed model.
The purpose of this article is to analyze the effect that halving has on the fair market value of bitcoins. The main hypothesis of the study is that the decline in the cost of miners’ remuneration for mining is a significant factor that affects the price of cryptocurrencies. The article examines the factors that regulate the issuing process. The significance of a limited supply of bitcoin is detailed in the article, as well as the mechanism for the implementation of the issue of new bitcoins. The study compares the historical inflation data of the US dollar and the projected data on the inflation of bitcoin. The article analyzes the main technical element of cryptocurrency – halving – when the miner’s reward is halved. This analysis includes the mathematical methods of statistical data processing. Research results show that reducing remuneration by half every four years leads to an increased market value of the cryptocurrency. This relationship is clearly illustrated by the Kendall rank correlation method. The results of the study can have a significant impact on the fundamental assessment of bitcoin and can also enable investors to assess any of the existing and operating cryptocurrencies according to this method.
Blockchain is currently one of the most important topics in both the academia and industry world, mainly due to the effects that the continuing development of this new technology embraces. The adoption of this technology by FinTech companies constitutes the next step towards the expansion of blockchain and its sustainability. Search results in smart contracts by FinTech companies have shown a deep focus in challenges such as security, scalability, legal and regulatory, privacy or latency, with proposed solutions still to be far from being effective.
Plasma is a framework for scalable off-chain computation. We describe and evaluate Plasma Cash, an improved Plasma construction which leverages non-fungible tokens and Sparse Merkle Trees to reduce the data storage and bandwidth requirements for users. We analyze the cryptoeconomic exit and challenge mechanisms used to keep user funds secured, even when the Plasma Cash chain's consensus algorithm is compromised. A reference implementation is provided for evaluation. Finally, we briefly discuss further improvements that can be made to the Plasma Cash protocol such as arbitrary denomination payments, less user data checking, fast and optimistic exits.
Digital ledger teknologi kan enkelt automatisera Sverige som en jurisdiktion, inklusive automatisering av beskattning, och möjliggöra digitala regeringsval, säkra digitala nationella IDn, och en Svensk e-krona. Exakt vad som behövs för en Svensk digital ledger är en konsensus algoritm som ordnar ledgern under Svenska folkets kontroll, proof-of-vote, digitala motsvarigheten av representativ demokrati. Under proof-of-vote röstar Svenska medborgare fram validatorer, som sen följer motsvarande protokoll som i Bitcoin och Ethereum, e.g., konkurrerar om auktoritet utifrån konsensus algoritmen, Nakamoto konsensus, i proof-of-vote med dom folk-röster dom fått, motsvarande stake i proof-of-stake.
Alessio Meneghetti, Massimiliano Sala, Daniele Taufer
We lay the foundations for a blockchain scheme, whose consensus is reached via a proof of work algorithm based on the solution of consecutive discrete logarithm problems over the point group of elliptic curves. In the considered architecture, the curves are pseudorandomly determined by block creators, chosen to be cryptographically secure and changed every epoch. Given the current state of the chain and a prescribed set of transactions, the curve selection is fully rigid, therefore trust is needed neither in miners nor in the scheme proposers.
Com o aparecimento do Bitcoin surge pela primeira vez na história uma moeda totalmente digital, que é ao mesmo tempo, um sistema de pagamento descentralizado. Não existindo uma entidade central, o sistema funciona com base na verificação e consenso da comunidade, com o protocolo a ter os incentivos certos, de modo a manter-se em funcionamento sem paragens nem falhas desde a sua criação, há mais de 10 anos. O presente estudo tem como objetivo analisar a origem do Bitcoin e Blockchain, bem como o seu contexto tecnológico, económico e legal. Identificar as características que fazem do bitcoin uma boa moeda e quais as suas limitações, analisando a sua natureza e funcionalidade. Também é analisado a evolução de medidas estáticas e risco dos retornos do bitcoin, assim como essas medidas se comparam e qual a correlação do bitcoin com outros ativos financeiros.
The article deals with the investigation of acquisition cryptocurrency in time retrospective and aspects of its usage taking point to the change of the value and number of transactions by the most popular cryptocurrency Bitcoin, its usage, comparing with the most popular payment platforms and resources consumed per transaction. The methods of analysis of scientific resources and statistical data, systematisation and critical evaluation were used during the research process. Evaluation of the acquisition and usage of cryptocurrency, according to analysed aspects reveals various sides of the processes.
Bert-Jan Butijn, Damian A. Tamburri, Willem‐Jan van den Heuvel
Blockchain technology has gained tremendous popularity both in practice and academia. The goal of this article is to develop a coherent overview of the state of the art in blockchain technology, using a systematic(i.e.,protocol-based, replicable), multivocal (i.e., featuring both white and grey literature alike) literature review, to (1) define blockchain technology (2) elaborate on its architecture options and (3) trade-offs, as well as understanding (4) the current applications and challenges, as evident from the state of the art. We derive a systematic definition of blockchain technology, based on a formal concept analysis. Further on, we flesh out an overview of blockchain technology elaborated by means of Grounded-Theory.
This paper examines the relationship between Inverse Perpetual Swap contracts, a Bitcoin derivative akin to futures and the margin funding interest rates levied on BitMEX. This paper proves the Heteroskedastic nature of funding rates and goes onto establish a causal relationship between the funding rates and the Bitcoin inverse Perpetual swap contracts based on Granger causality. The paper further dwells into developing a predictive model for funding rates using best-fitted GARCH models. Implications of the results are presented, and funding rates as a predictive tool for gauging the market trend is discussed.