scholarly journals Strangely mined bitcoins: Empirical analysis of anomalies in the bitcoin blockchain transaction network

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0258001
Author(s):  
María Óskarsdóttir ◽  
Jacky Mallett

The blockchain technology introduced by bitcoin, with its decentralised peer-to-peer network and cryptographic protocols, provides a public and accessible database of bitcoin transactions that have attracted interest from both economics and network science as an example of a complex evolving monetary network. Despite the known cryptographic guarantees present in the blockchain, there exists significant evidence of inconsistencies and suspicious behavior in the chain. In this paper, we examine the prevalence and evolution of two types of anomalies occurring in coinbase transactions in blockchain mining, which we reported on in earlier research. We further develop our techniques for investigating the impact of these anomalies on the blockchain transaction network, by building networks induced by anomalous coinbase transactions at regular intervals and calculating a range of network measures, including degree correlation and assortativity, as well as inequality in terms of wealth and anomaly ratio using the Gini coefficient. We obtain time series of network measures calculated over the full transaction network and three sub-networks. Inspecting trends in these time series allows us to identify a period in time with particularly strange transaction behavior. We then perform a frequency analysis of this time period to reveal several blocks of highly anomalous transactions. Our technique represents a novel way of using network science to detect and investigate cryptographic anomalies.

2018 ◽  
Vol 33 (2) ◽  
pp. 105-125 ◽  
Author(s):  
Darcy W.E. Allen ◽  
Chris Berg ◽  
Mikayla Novak

This paper incorporates blockchain activities into the broader remit of entangled political economy theory, emphasising economic and other social phenomena as the emergent by-product of human interactions. Blockchains are a digital technology combining peer-to-peer network computing and cryptography to create an immutable decentralised public ledger. The blockchain contrasts vintage ledger technologies, either paper-based or maintained by in-house databases, largely reliant upon hierarchical, third-party trust mechanisms for their maintenance and security. Recent contributions to the blockchain studies literature suggest that the blockchain itself poses as an institutional technology that could challenge existing forms of coordination and governance organised on the basis of vintage ledgers. This proposition has significant implications for the relevance of existing entangled relationships in the economic, social and political domains. Blockchain enables non-territorial 'crypto-secession', not only reducing the costs associated with maintaining ledgers, but radically revising and deconcentrating data-conditioned networks to fundamentally challenge the economic positions of legacy firms and governments. These insights are further illuminated with reference to finance, property and identity cases. Entangled political economy provides a compelling lens through which we can discern the impact of blockchain technology on some of our most important relationships.


2021 ◽  
Vol 54 (3) ◽  
pp. 1-28
Author(s):  
Jun Huang ◽  
Debiao He ◽  
Mohammad S. Obaidat ◽  
Pandi Vijayakumar ◽  
Min Luo ◽  
...  

Voting is a formal expression of opinion or choice, either positive or negative, made by an individual or a group of individuals. However, conventional voting systems tend to be centralized, which are known to suffer from security and efficiency limitations. Hence, there has been a trend of moving to decentralized voting systems, such as those based on blockchain. The latter is a decentralized digital ledger in a peer-to-peer network, where a copy of the append-only ledger of digitally signed and encrypted transactions is maintained by each participant. Therefore, in this article, we perform a comprehensive review of blockchain-based voting systems and classify them based on a number of features (e.g., the types of blockchain used, the consensus approaches used, and the scale of participants). By systematically analyzing and comparing the different blockchain-based voting systems, we also identify a number of limitations and research opportunities. Hopefully, this survey will provide an in-depth insight into the potential utility of blockchain in voting systems and device future research agenda.


2021 ◽  
Author(s):  
Burcu Sakız ◽  
Ayşen Hiç Gencer

Blockchain technology is a disruptive innovation with the potential to replace existing business models that rely on centralized systems and third parties for trust. Even if there are a lot of application areas, blockchain used primarily for cryptocurrencies. Satoshi Nakamoto implemented the first blockchain application and invented the world’s first digital currency which is named as Bitcoin in 2008. Fundementally Bitcoin relies on cryptographic “proof of work” mechanism, digital signatures, and peer to peer distributed networking layer in order to provide a distributed ledger holding transactions. In 2014, a second generation of blockchains allow to program and execute them over distributed networks such as Ethereum project. The code to program any asset stored in blockchain’s peer-to-peer network is called as "smart contract" and smart contracts gives a powerful tool to developers for decentralized applications. There are various types of tokens that anyone can built on top of Ethereum and by combining smart contracts and new tokens, this paved the way of possibility to build a wide range of decentralized projects. One of the disruptive blockchain based innovation impacting intellectual property is called non-fungible-tokens or NFTs firstly introcuced in late 2017 on Ethereum network. This research contends that blockchain and non-fungible tokens (NFTs) which are cryptographically unique, scarce, non-replicable digital assets created through smart contracts and provably digital collectible assets. Our objective is to give NFT taxonomy, review NFT platforms and discuss technical challenges as well as recent advances in tackling the challenges. Moreover, this paper also aims to point out the future directions for NFT technology.


2021 ◽  
Author(s):  
HongLing Liu ◽  
Yuqiang Chen

Abstract Blockchain technology has become more important in recent years in Internet of Things (IoT) manufacturing. Many IoT manufacturing factories have successively invested in the blockchain architecture in the system to manage the data of the IoT manufacturing system for intelligence prediction. The blockchain-based system architecture can ensure the process of data transmission and preservation. However, the use of storage space in industrial IoT systems using blockchain architecture will become a major challenge. Since the blockchain itself is based on the concept of a peer-to-peer network, any node must hold complete blockchain information. When there are thousands of nodes, the cost of hard disk space for storing these data will increase drastically as the number of nodes increases. In addition, newly added working nodes must also copy the original complete blockchain information, and will increase in expansion costs. In order to solve the above problems, this paper proposed a blockchain structure to reduce the space and network transmission costs. The architecture divides the traditional blockchain into two parts, which are divided into private blockchain and public blockchain according to the edge and the cloud. Each workshop will manage its own private blockchain, and the cloud will manage itself public blockchain. Under the proposed structure, each working node only needs to maintain the blockchain at its edge node, and does not need to communicate with other edge node. The experimental results, it can effectively intelligence predict the space cost of node expansion, and it can also avoid the unnecessary network communication overhead caused by the traditional architecture. It can improve the space used of blockchain and reduce the network transfer time.


2019 ◽  
Vol 8 (4) ◽  
pp. 5795-5802

Blockchain Technology is one of the most popular technologies of present days. This technology has the capability to eliminate the requirement of third party to validate the transactions over the Peer-to-Peer network. Due to various features of Blockchain like smart contract, consensus mechanism, network transactions are completed securely, efficiently and timely. This technology is very useful in many areas including medical, IoT, e-Governance services, smart cities, taxation, supply chain, banking etc. In this paper, we discuss the Blockchain Technology in detail, its data structure, open source platform like Ethereum and Hyperledger, technical aspects of this technology, possible applications of this technology, challenges and limitations in adaptation of this technology.


Author(s):  
Peter Anderson ◽  
Eva Jané Llopis ◽  
Amy O’Donnell ◽  
Eileen Kaner

Abstract Aims To investigate if COVID-19 confinement led to excess alcohol purchases by British households. Methods We undertake controlled interrupted time series analysis of the impact of COVID-19 confinement introduced on 26 March 2020, using purchase data from Kantar Worldpanel’s of 23,833 British households during January to early July 2020, compared with 53,428 British households for the same time period during 2015–2018. Results Excess purchases due to confinement during 2020 were 178 g of alcohol per 100 households per day (adjusted for numbers of adults in each household) above an expected base of 438 g based on averaged 2015–2018 data, representing a 40.6% increase. However, when adjusting for expected normal purchases from on-licenced premises (i.e. bars, restaurants, etc.), there was evidence for no excess purchases of grams of alcohol (a 0.7% increase). With these adjustments, beer purchases dropped by 40%, wine purchases increased by 15% and spirits purchases by 22%. Excess purchases increased the richer the household and the lower the age of the main shopper. Confinement was associated with a shift in purchases from lower to higher strength beers. Conclusion During the COVID-19 confinement, the evidence suggests that households did not buy more alcohol for the expected time of the year, when adjusting for what they normally would have purchased from on-licenced premises.


Author(s):  
Burcu Sakız ◽  
E. Ayşen Hiç Gencer

Satoshi Nakamoto is the name used by the presumed pseudonymous person or persons believed to be the inventor of cryptocurrency Bitcoin, came up with the concept of blockchain as a core component of it when published a white paper on “BitCoin: A peer to peer electronic cash system” in 2008, blockchain technology made its public debut. Bitcoin is generally considered the first decentralized cryptocurrency and since the release of it, over 6,000 altcoins have been created. Cryptocurrencies use decentralized control as opposed to well-known, traditional centralized digital currency and also central banking systems. The decentralized control of each cryptocurrency works through distributed ledger technology, typically a blockchain. Blockchain is a system that in which a record of transactions made in cryptocurrencies are maintained across several computers/servers that are linked in a peer-to-peer network. Blockchain based applications provides many opportunities to create a more sustainable world. This paper contribute to the discussion on future avenues for sustainability especially in terms of cryptocurrencies and blockchain based platforms and services.


INSIST ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 191
Author(s):  
Jiangdong Cao ◽  
Wei Cao

Bitcoin is a crypto currency introduced by Satoshi Nakamoto in 2008. It has the features of decentralization cross-border and fixed total amount and has become one of the most widely used crypto-currencies. Bitcoin, as a new digital currency system, innovatively makes the use of cryptographic elements and consensus mechanisms and builds up a secure decentralized system. The Blockchain, as the core of Bitcoin, uses peer-to-peer network communications and backs up transaction data in every node of the system, thus creating a huge distributed public book.  It is essentially a decentralized distributed ledger database, and the decentralization means that the transaction is broadcast to the entire network, where everyone is involved in book keeping. In order to make every participant in the Blockchain willing to participate in the bookkeeping, the reward mechanism of the Bitcoin system is mining. This article first introduces the concept of Blockchain technology, then expounds the principle and the operation mechanism of the Bitcoin and the Bitcoin mining principle, introduces an example of Bitcoin mining in-depth study and analysis, finally, summarize and prospect the development of the Bitcoin mining.


The idea of the cryptocurrency was to decentralize the currency system by establishing transactions over distributed peer to peer network [1]. The technology of Blockchain was adopted to achieve this motive. The term blockchain comes from the idea of list of blocks, growing continuously over time wherein every block carries the data relating to the transactions and data regarding the cryptographical linkage using secure hash algorithms and the protocols [2]. Through this paper, we have shown the implementation of the blockchain technology so as to build the cryptocurrency. While building up the cryptocurrency, called the ‘SantCoin’, the idea about how this technology can revolutionize the traditional existing ledger systems can be upgraded so as to implement secure means of transactions over a distributed network. This implementation work suggests the use of technology in almost every governing body so that they can secure themselves and limit the dependency on human resource to do their central authoritative work [3].


2020 ◽  
Author(s):  
Debjyoti Talukdar ◽  
Dr. Vrijesh Tripathi

BACKGROUND Rapid spread of SARS nCoV-2 virus in Caribbean region has prompted heightened surveillance with more than 350,000 COVID-19 confirmed cases in 13 Caribbean countries namely Antigua and Barbados, Bahamas, Barbados, Cuba, Dominica, Dominican Republic, Grenada, Haiti, Jamaica, Saint Kitts and Nevis, Saint Lucia, Saint Vincent and the Grenadines, Trinidad and Tobago. OBJECTIVE The aim of our study is to analyze the impact of coronavirus (SARS nCoV-2) in 13 Caribbean countries in terms of confirmed cases, number of deaths and recovered cases. Current and projected forecasts using advanced autoregressive integrated moving average (ARIMA) models will enable local health organisations to plan future courses of action in terms of lockdown and managing essential public services. METHODS The study uses the auto regressive integrated moving average (ARIMA) model based upon time series pattern as per data retrieved from John Hopkins University, freely accessible on public domain and used for research and academic purposes. The data was analyzed using STATA 14 SE software between the time period - Jan 22, 2020 till May 27, 2020 using ARIMA time series analysis. It involves generalizing an autoregressive moving average model to better understand the data and predict future points in the time series until June 15, 2020. RESULTS The results show the predicted trend in terms of COVID-19 confirmed, mortality and recovered cases for 13 Caribbean countries. The projected ARIMA model forecast for the time period - May 25, 2020 to May 31, 2020 show 20278 (95% CI 19433.21 - 21123.08) confirmed cases, 631 (95% CI 615.90 - 646.51) deaths and 11501 (95% CI 10912.45 - 12089) recovered cases related to SARS nCoV-2 virus. The final ARIMA model chosen for confirmed COVID-19 cases, number of deaths and recovered cases are ARIMA (4,2,2), ARIMA (2,1,2) and ARIMA (4,1,2) respectively. All chosen models were compared with other models in terms of various factors like AIC/BIC (Akaike Information Criterion/Bayesian Information Criterion), log likelihood, p-value significance, coefficient < 1 and 5% significance. The autocorrelation function (ACF) and partial autocorrelation function (PACF) graphs were plotted to reduce bias and select the best fitting model. CONCLUSIONS As per the results of the forecasted COVID-19 models, there is a steady rise in terms of confirmed, recovered and mortality cases during the time period March 1, 2020 until May 27, 2020. It shows an increasing trend for confirmed and recovered COVID-19 cases and slowing of the number of mortality cases over a period of time. The predicted model will help the local health administration to devise public policies in terms of awareness measures, lockdown and essential health services accordingly.


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