Article

Overview of Block Chain

February 2019

Authors:

Indhumathi Subramaniam

Cryptographyis used for merging the upcoming list of record in block chain..Every block contain a cryptographic hashof the previous block atimestamp,and transaction data (generally represented as amerkle tree root hash).In 2008, Blockchain was invented by a person using the nameSatoshi Nakamototo serve as public transaction ledgerof cryptocurrencybitcoin.The identity of Satoshi Nakamoto is unknown. The invention of the block chain for bitcoin made the first digital currency to solve the double-expenditure problem without the need of a trusted authority . The bitcoin design has inspired other applications, and blockchains which are readable by the public are widely used by cryptocurrency.

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Conference Paper

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Evaluation of Proof of Work (POW) Blockchains Security Network on Selfish Mining

February 2019

Bitcoin is one of the first implementations of cryptocurrency or digital currency. It uses has increased in recent years along with the increasing volume of online transactions that require digital currency A blockchain is a digital ledger that allows parties to transact without use of a central authority as a trusted intermediary. In blockchain, there are a number of consensus protocols proposed ... [Show full abstract] including Proof of Stake, Proof of Elapsed Time, but most of the existing blockchain utilizes the computed Proof of Work (PoW) mechanism. Transaction security is secured in Bitcoin by using blocks with a hash-based Proof of Work (PoW) mechanism. PoW is a functional protocol that validates every incoming data to overcome spam attacks and Distributed Denial of Service (DDoS) attacks. Blockchain technology can store historically decentralized transaction data where each connected computer will store exactly the same data. To be able to perform an optimal transaction process, it is necessary to evaluate performance of the POW blockchain and find out what influences the transaction process. In this study, we compare simulation result of different block size and block interval to Block Propagation Time, time setup, and Average upload/download with selfish mining attack using NS3. The experimental results show that the smaller the block interval and block size, the smaller the Block Propagation time. It means that faster transactions are confirmed to peers on the network, and this affects the upload/download speeds.

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Blockchain update - Post-Bitcoin Cryptocurrencies - Society has to shape technology

June 2018

Helmut Leopold

A blockchain is a general concept that comprises multiple technical functions. The basic principle behind it is that data is not stored centrally, but is distributed to all participants in a fully meshed peer-to-peer network. This creates a distributed ledger in which all data and all transactions can be viewed at all times by all participants in a blockchain in the same way. This enables each ... [Show full abstract] user to check the validity of his or her data and the transactions that have been completed. This method uses specific functions created to ensure that data and transactions cannot be modified. No one person using the blockchain can alter the data or transactions without the other users noticing. The technology thus inherently implements by technical means a level of "trust" between the users of a blockchain. Instead of storing the results of transactions, each individual transaction is preserved in its entirety; i.e. calculating the balance of an account for a virtual currency like Bitcoin, requires that the complete history of all Bitcoin transactions can be viewed in their entirety. Technical concepts underlying blockchains The block The most basic structure of a blockchain is the block. The block is a container for data values and transactions and these blocks are connected to one another by links forming a chain, i.e. one link to the previous block and one link to the next block. This creates what is known as a blockchain. (The very first block is called the "Genesis block"). A block usually contains multiple transactions; e.g. in Bitcoin, which is a blockchain application, a block is generated every 10 minutes. This process is also called "min-ing"-this mechanism will be discussed in more detail below.

Preprint

Managed Blockchain Based Cryptocurrencies with Consensus Enforced Rules and Transparency

June 2019

Peter Mell

Blockchain based cryptocurrencies are usually unmanaged, distributed, consensus-based systems in which no single entity has control. Managed cryptocurrencies can be implemented using private blockchains but are fundamentally different as the owners have complete control to do arbitrary activity without transparency (since they control the mining). In this work we explore a hybrid approach where a ... [Show full abstract] managed cryptocurrency is maintained through distributed consensus based methods. The currency administrator can perform ongoing management functions while the consensus methods enforce the rules of the cryptocurrency and provide transparency for all management actions. This enables the introduction of money management features common in fiat currencies but where the managing entity cannot perform arbitrary actions and transparency is enforced. We thus eliminate the need for users to trust the currency administrator but also to enable the administrator to manage the cryptocurrency. We demonstrate how to implement our approach through modest modifications to the implicit Bitcoin specification, however, our approach can be applied to most any blockchain based cryptocurrency using a variety of consensus methods.

Conference Paper

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On the optionality and fairness of Atomic Swaps

October 2019

Atomic Swap enables two parties to atomically exchange their own cryptocurrencies without trusted third parties. This paper provides the first quantitative analysis on the fairness of the Atomic Swap protocol, and proposes the first fair Atomic Swap protocol with implementations. In particular, we model the Atomic Swap as the American Call Option, and prove that an Atomic Swap is equivalent to an ... [Show full abstract] American Call Option without the premium. Thus, the Atomic Swap is unfair to the swap participant. Then, we quantify the fairness of the Atomic Swap and compare it with that of conventional financial assets (stocks and fiat currencies). The quantification results show that the the Atomic Swap is much more unfair on cryptocurrencies than on stocks and fiat currencies in the same setting. Moreover, we use the conventional Cox-Ross-Rubinstein option pricing model in Finance to estimate the premium, and show that the estimated premium for cryptocurrencies is 2% ~ 3% of the asset value, while the premium for stocks and fiat currencies is approximately 0.3%. Furthermore, we propose two fair Atomic Swap protocols, one is for currency exchange and the other is for American Call Options. Our protocols are based on the original Atomic Swap protocol, but implement the premium mechanism. Blockchains supporting smart contracts such as Ethereum support our protocols directly. Blockchains only supporting scripts such as Bitcoin can support our protocols by adding a simple opcode. Finally, we provide the reference implementation of our protocols in Solidity, and give detailed instructions on implementing our protocols with Bitcoin script.

Chapter

Blockchain Technology

January 2020

More than hundred countries have experienced WannaCry Ransomware cyber-attack in 2017. This attack demanded around $300 of Bitcoin cryptocurrency from users to retrieve their data. There onwards, Blockchain technology and cryptocurrency are catching the attention of everyone. Blockchain is a growing digital record keeping register in the distributed form which cannot be altered. In case of ... [Show full abstract] Blockchain, no central authority is needed. Modification of the data or assets stored on Blockchain is highly difficult or nearly impossible. All the data available on Blockchain can be publicly seen by everyone. It cuts down the excessive costs required in the conventional manual record keeping registers. Blockchain technology has lot of bonus points including integrity, write access, reduced cost, trust, etc. With Blockchain technology, various tokens are available such as currency tokens, asset tokens, utility tokens, and equity tokens.

Conference Paper

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Securities on Blockchain in Order to Engage with Blockchain Technologies to Build a Comprehensive, A...

May 2019

Associate Prof Dr Mahadi Hasan Miraz

Abstract – This paper analysis and describe the blockchain technology and its operation on various system and securities in business transactions. In addition, this article primarily offers a advanced explanation of this new innovation reachable to everyone form various field, and descriptive outlines of current blockchain which indicates the safeties delivered and actuality transacted. It ... [Show full abstract] also studies the constrictions of Uniform Commercial Code and blockchain securities as “uncertificated securities”. Furthermore, it describes the Uniform Commercial Code include blockchain safeties by way of “uncertificated securities” for better understanding of blockchain trades. Moreover, Blockchain technologies grip the key to construction a comprehensive international digital economy that is audit-able safe and evidently accountable to the world wide’s residents. Besides, the regime needs reestablish trust in modern financial cooperation; blockchains lead a significant part in establishment and advantages of both parties. This article objective is to identify the securities in blockchain, Distributed ledger and crypto currency for local and international trade. Keywords – international trade; trade securities, blockchain & its securities, distributed ledger; tangle; crypto currency; Bitcoin; tools; invention; global collaboration; trade; financial system

Conference Paper

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PlasticCoin: an ERC20 Implementation on Hyperledger Fabric for Circular Economy and Plastic Reuse

October 2019

Cryptocurrencies have gained popularity in the last few years, thanks to the democratization of Bitcoin. However, most of these currencies have a very general purpose, namely of allowing people to pay their products with an electronic, decentralised currency. Moreover, the lack of trust of these open-network blockchains comes at a significant economic cost. In this paper, we present PlasticCoin, ... [Show full abstract] a cryptocurrency empowering plastic reuse in a circular economical model, that anyone can join, and that respects the ERC20 specifications on a consortium blockchain. We also explore the economical ecosystem revolving around PlasticCoin, and also introduce a way to print tickets that can temporarily hold the role of physical banknotes. Finally, we show that our system is flexible, and it can be adapted to many other business purposes.