An analysis of acceptance policies for blockchain transactions

The standard acceptance policy for a cryptocurrency transaction at most exchanges is to wait until the transaction is placed in the blockchain and followed by a certain number of blocks. However, as noted by Sompolinsky and Zohar [16], the amount of time for blocks to arrive should also be taken into account as it affects the probability of double spending. Specifically, they propose a dynamic policy for transaction acceptance that depends on both the number of confirmations and the amount of time since transaction broadcast. In this work we study the implications of using such a policy compared with the standard option that ignores block timing information. Using an exact expression for the probability of double spend, via numerical results, we analyze time to transaction acceptance (performance) as well as the time and cost to perform a double spend attack (security). We show that while expected time required for transaction acceptance is improved using a dynamic policy, the time and cost to perform a double spend attack for a particular transaction is reduced.First author draf

k-Root-n: An Efficient Algorithm for Avoiding Short Term Double-Spending Alongside Distributed Ledger Technologies such as Blockchain

Blockchains such as the bitcoin blockchain depend on reaching a global consensus on the distributed ledger; therefore, they suffer from well-known scalability problems. This paper proposes an algorithm that avoids double-spending in the short term with just O(√n) messages instead of O(n); each node receiving money off-chain performs the due diligence of consulting k√n random nodes to check if any of them is aware of double-spending. Two nodes receiving double-spent money will in this way consult at least one common node with very high probability, because of the ‘birthday paradox’, and any common honest node consulted will detect the fraud. Since the velocity of money in the real world has coins circulating through at most a few wallets per day, the size of the due diligence communication is small in the short term. This ‘k-root-n’ algorithm is suitable for an environment with synchronous or asynchronous (but with fairly low latency) communication and with Byzantine faults. The presented k-root-n algorithm should be practical to avoid double-spending with arbitrarily high probability, while feasibly coping with the throughput of all world commerce. It is resistant to Sybil attacks even beyond 50% of nodes. In the long term, the k-root-n algorithm is less efficient. Therefore, it should preferably be used as a complement, and not a replacement, to a global distributed ledger technology.</jats:p

An Efficient and Secure Energy Trading Approach with Machine Learning Technique and Consortium Blockchain

In this paper, a secure energy trading mechanism based on blockchain technology is proposed. The proposed model deals with energy trading problems such as insecure energy trading and inefficient charging mechanisms for electric vehicles (EVs) in a vehicular energy network (VEN). EVs face two major problems: finding an optimal charging station and calculating the exact amount of energy required to reach the selected charging station. Moreover, in traditional trading approaches, centralized parties are involved in energy trading, which leads to various issues such as increased computational cost, increased computational delay, data tempering and a single point of failure. Furthermore, EVs face various energy challenges, such as imbalanced load supply and fluctuations in voltage level. Therefore, a demand-response (DR) pricing strategy enables EV users to flatten load curves and efficiently adjust electricity usage. In this work, communication between EVs and aggregators is efficiently performed through blockchain. Moreover, a branching concept is involved in the proposed system, which divides EV data into two different branches: a Fraud Chain (F-chain) and an Integrity Chain (I-chain). The proposed branching mechanism helps solve the storage problem and reduces computational time. Moreover, an attacker model is designed to check the robustness of the proposed system against double-spending and replay attacks. Security analysis of the proposed smart contract is also given in this paper. Simulation results show that the proposed work efficiently reduces the charging cost and time in a VEN.publishedVersio

A utilização de tecnologias na contabilidade pela perspectiva da literatura nacional

The advancement of Information Technology (IT) has provided significant changes in the scope of work within organizations, also affecting the accountant's routine. In this aspect, this study aims to analyze the use of technology in accounting from the perspective of the national literature. For this, through the Spell platform, a research was made for articles related to accounting and technology, searching in accounting journals with Qualis strata from A2 to B3 from CAPES between 2012 and 2021. To achieve this objective, this paper used a descriptive character regarding the objective, with a quantitative approach and bibliographic research procedures. The main contribution of the study is to trace a profile of evolution and trends for the use of technologies in accounting, following the dynamics of business and the globalized world in constant transformation. In the social sphere, the study can contribute, both to accounting education and to the accountant's own professional performance, by offering an overview of what can/should be learned in relation to technology and its application in accounting. The research results demonstrate agreement among the authors, that the technologies studied by each one contributes in some way to the optimization of work within the companies. Among the subjects of interest, there was a constancy related to the publications of SPED and blockchain themes. Also, it’s observed a concern to understand the determining factors for the implementation or acceptance of cloud computing tools, ERPs and the use of big data.Pesquisa sem auxílio de agências de fomentoTrabalho de Conclusão de Curso (Graduação)O avanço da Tecnologia da Informação (TI) vem proporcionando modificações significativas no escopo de trabalho dentro das organizações, afetando, também, a rotina do contador. Nesse aspecto, o presente estudo tem o objetivo de analisar a utilização de tecnologias na contabilidade, pela perspectiva da literatura nacional. Para isso, através da plataforma Spell, buscou-se, nos periódicos contábeis com estratos Qualis de A2 a B3 da CAPES entre 2012 e 2021, artigos relacionados à contabilidade e tecnologia. Para alcançar tal objetivo, o trabalho utilizou de um caráter descritivo quanto ao objetivo, com abordagem quantitativa e procedimentos de pesquisa bibliográfica. A principal contribuição do estudo consiste em traçar um perfil de evolução e tendências para o uso de tecnologias na contabilidade, acompanhando a dinâmica dos negócios e o mundo globalizado em constante transformação. No âmbito social, o estudo pode contribuir, tanto para a educação contábil como para a própria atuação profissional do contador, ao oferecer um panorama daquilo que pode/deve ser aprendido em relação à tecnologia e sua aplicação na contabilidade. Os resultados da pesquisa demonstram concordância entre os autores de que as tecnologias estudadas por cada um contribuem, de alguma maneira, para a otimização do trabalho dentro das organizações. Dentre os assuntos de interesse, foi observada uma constância relacionada às publicações dos temas SPED e da blockchain. Observa-se uma preocupação em entender os fatores determinantes para a implementação ou aceitação das ferramentas de computação em nuvem, dos ERPs e do uso da big data

k-root-n: An efficient algorithm for avoiding short term double-spending alongside distributed ledger technologies such as blockchain

Blockchains such as the bitcoin blockchain depend on reaching a global consensus on the distributed ledger; therefore, they suffer from well know scalability problems. This paper proposes an algorithm that avoids double-spending in the short term with just O(&#8730;n) messages instead of O(n); each node receiving money off-chain performs the due diligence of consulting k&#8730;n random nodes to check if any of them is aware of double-spending. Two nodes receiving double-spent money will in this way consult at least one common node with very high probability, due to the ‘birthday paradox’, and any common honest node consulted will detect the fraud. Since the velocity of money in the real world has coins circulating through at most a few wallets per day, the size of the due diligence communication is small in the short term. This `k-root-n’ algorithm is suitable for an environment with synchronous or asynchronous (but with fairly low latency) communication and with Byzantine faults. The presented k-root-n algorithm should be practical to avoid double-spending with arbitrarily high probability, while feasibly coping with the throughput of all world commerce. It is resistant to Sybil attacks even beyond 50% of nodes. In the long term, the k-root-n algorithm is less efficient. Therefore, it should preferably be used as a complement, and not a replacement, to a global distributed ledger technology