Proof of Existence Using Blockchain

It has been more than 10 years since Satoshi Nakamoto published his famous paper entitled ‘Bitcoin: a peer-to-peer electronic cash system’, which set the foundation of blockchain technology. Accompanied by the price volatility of bitcoins from 2017 to 2018, blockchain has been a hot word on the internet, and particularly hot in China. Blockchain offers a distributed and secure system for data storage and value transactions. Its applications are springing up in multiple fields.The Chinese government is considering these trends with great caution. Initial coin offering has been banned in China since September 2017. By contrast, an official white paper on China's blockchain technology, which was released in May 2018, said that blockchain technology will be widely applied in the real economy of China within 3 years. In a recent panel discussion held by National Science Review, experts talked about related topics. Their opinions may provide a quick view of the future development of blockchain in China and abroad. Jing Chen Assistant Professor of Computer Science Department, Stony Brook University and Chief Scientist at Algorand LLC, USA Xiaotie Deng Professor of School of Electronics Engineering and Computer Science, Peking University, China Guohua Gan Vice President of Beijing Tai Cloud Technology Corp., China Xiaoyun Wang Professor of Institute of Advanced Study, Tsinghua University, China Zhiming Zheng Professor of School of Mathematics and Systems Science, Beihang University, China Lei Guo (Chair) Professor of Academy of Mathematics and Systems Science, Chinese Academy of Sciences, China

Blockchain technology originated in 2008 when an author codenamed Satoshi Nakamoto published the paper titled “Bitcoin: A Peer-To-Peer Electronic Cash System.” The publication presented an innovative combination of computing-related concepts – peer-to-peer (P2P) networks, cryptography, digital signature, hash functions, and a new consensus algorithm for distributed networks. The Bitcoin network utilizes blockchain technology to process and record transactions securely, and performs online payments without needing a trusted third party. Transactions are validated and recorded in blocks stored in ledger format at network nodes. A “block” refers to the network state stored in sequential blocks containing transactions, hence the term blockchain. One of the limitations of Bitcoin is that its blockchain only allows the sending of monetary transactions. In 2013, Vitalik Buterin, a former member of the Bitcoin community, proposed a platform for developing decentralized applications called Ethereum. This blockchain can run the so-called “Smart Contracts”, or computational codes (programs) that run autonomously and reliably on the blockchain.

The current digital and technological changes make bitcoin trading more and more popular. Virtual money (cryptocurrency) is no longer just a fashion, but it is more and more often used in practice on the Internet, and there are no statutory provisions in Polish law, which can lead to many legal complications. Bitcoin first appeared in 2008 thanks to a user disguised as Satoshi Nakamoto who published an article titled Bitcoin: A Peer-to-Peer Electronic Cash System. The concept of bitcoin was published in a nine-page document, and the essence of the concept was the actual creation, launch and placement of a software based on a very complex algorithm for generating bitcoin, based on e.g. on blockchain technology. Satoshi proposed a solution to the problem that had existed since the inception of the Internet, ie how to create a universal electronic payment system. The basic idea of the creator of the bitcoin system was to maintain the anonymity of transactions and property and to exclude unnecessary intermediaries from circulation. From the point of view of computer science, the bitcoin network is a decentralized database of information about the flow of certain numerical values between accounts of system users, where the above numerical values constitute the bitcoin currency. The state and public institutions, in turn, decide on the issue of this currency, its size and creation.The issue of bitcoin forces lawyers to investigate primarily at the level of civil law. The article presents the issues of bitcoin at the level of Polish civil law, and above all de lege lata considerations in the field of both civil and family law regarding the issue of bitcoin division after the divorce of spouses. Discrepancies appearing in the Polish doctrine on the civil law assessment of the nature of bitcoin are presented.

At its core, a blockchain is simply a database for storing digital information where each of time-stamped, published data is together with all preceding and subsequent blocks. What makes blockchain unique from traditional data storage is that data is not stored or controlled within a centralized database, but rather database management is shared by a decentralized network of trustless nodes that each maintain an identical copy of the blockchain. Before data can be published to the blockchain, it must first be validated by a majority of network nodes—typically referred to as or, depending on the consensus methodology used. This concept of “distributed consensus” makes the blockchain inherently tamper resistant and ensures that only verified transactions will be published to the blockchain.1 The two primary consensus methodologies used in blockchain technology today are , first popularized in 2008 by the founder(s) of the Bitcoin2 blockchain, and , which has been used extensively in the development of derivative blockchain projects to help solve the issues of scalabil- 1 Samantha Ravich, “Leveraging Blockchain Technology to Protect the National Security Industrial Base,” July 10, 2017, https://www.fdd.org/analysis/memos/2017/07/10/leveraging-block chain-technology-to-protect-the-national-security-industrial-base/ 2 Satoshi Nakamoto, “Bitcoin: A Peer-to-Peer Electronic Cash System,” 2008, https://bicoin.org/ bitcoin.pdf ity and energy consumption associated with proof-of-workbased blockchains.

Cryptocurrency is a relatively young research field. Since its development, when Bitcoin was lanced (2008) (Satoshi, N.: Bitcoin: A Peer-to-Peer Electronic Cash System (2008)), until today it become a highly volatile market with more than 9 thousand types of cryptocurrencies (CoinMarketCap: preţurile criptomonedelor de ast˘azî in funcţie de capitalizare de piaţă (2021)). In latest years several algorithms and techniques have been developed in order to predict the cryptocurrency price evolution. However, a general classification of the available methods has not been proposed yet. For these reasons, in this paper the main ideas underlying cryptocurrency price forecasting are presented and compared. In the first part of the paper is presented the general framework of cryptocurrency development, namely Blockchain Technology and e-Business social environment. In the second part several techniques for cryptocurrency price prediction are presented and their main characteristics are discussed. The last section concludes.KeywordsBitcoinPrice forecastingBlockchainCryptocurrency

The days of storing data manually are behind us. We are opting for the online form of data storage and transfer. The new era of data digitization comes with its own perks and detriments. Cybersecurity is still a crucial concern today. As more data transfer occurs through an online medium, the risks of a breach and cyberattacks are inevitable. The whole foundation of e-commerce is based on the online transfer of goods and transactions without the need to travel. Transferring transactional data and transactions in e-commerce are prone to cyber threats. Our research’s major objective is to develop a system that protects against such mishaps, especially during the transfer of transactional data, and also implement an automated system that ensures these transactions occur without any errors. To implement this, we are taking advantage of new emerging technologies called blockchain and smart contract. Blockchain allows a decentralized, immutable digital ledger to safely store and transfer data across the network. Blockchain technology is used in e-commerce to transfer transactions in a safe, secure, and faster way. Blockchain enables a peer-to-peer transaction system and data encryption that enables the safe transfer of transactional data. Blockchain is used to transfer transactional data. A smart contract is a special program that enables, verifies, and enforces the terms of a contract digitally. It provides transactional security as the contact is in place. The blockchain, coupled with smart contracts, will revolutionize the future of e-commerce. We have combined blockchain technology to ensure data security and user privacy with smart contracts to ensure that the protocol for the transaction is maintained. The results are presented by building and implementing the proposed system that provides the solution for transactional data privacy.

One important requirement of electronic cash systems is the anonymity of customers. Unconditional anonymity is also very well suited to support criminals in blackmailing. Maitland and Boyd proposed at ICICS 2001 an offline electronic cash system based on a group signature scheme. Their scheme cannot be used to solve blackmailing and other anonymity problems such as money laundering and illegal purchases. Chen, Zhang and Wang suggested an offline electronic cash scheme to prevent blackmailing by using the group blind signature. In their payment system, they used a group signature scheme of Camenisch and Stadler for large groups which is not secure. In this paper we improve these electronic cash systems to prevent blackmailing, money laundering and illegal purchases by using a secure coalition-resistant group blind signature scheme.

Block chain is a technology that is used to save the record of all information related to crypto currency transactions in a public ledger. Digital currency transactions can be done without any third party. When a coin is transferred by a computer, its information reaches all the computers connected to the network, and the transaction is verified. After this, the transaction data is secured by encoding it in blocks using cryptography technology. Similarly, many types of blocks together form the Public Ledger, which is called Block chain. During this hackathon, the winners will also be awarded up to three lakh rupees. Block chain has been the topic of discussion all over the world in recent times. Ever since the crypto currency era began, block chain has come into the limelight more and more, because crypto currency works on block chain technology itself.

Recently, the first ID-based restrictive partially blind signature scheme from bilinear pairing is proposed by Chen et al., which extends the concept of blind signature and possesses the excellent features of partially blind signature, restrictive blind signature and ID-based cryptosystem simultaneously. However, its computational cost is rather high. In order to improve its efficiency, Hu et al. presented another efficient scheme which requires less computing cost. Unfortunately, we find that an adversary can change the predetermined common information, which may include the expiry date and the face value of the e-cash in electronic cash system, without being discovered by the signer. So Hu et al.psilas scheme has security flaw when it is used in electronic cash system. In this paper, we present an improved ID-based restrictive partially blind signature scheme from bilinear pairing which overcomes the security weakness of Hu et al.psilas scheme. We analyze the security of our scheme in the random oracle model and compared the efficiency of our scheme with previous schemes.

The aim of this paper is to contextualize briefly the emergence and development of Bitcoin as well as to offer an anthropological analysis of one such "algorithmic utopia" known as Bitcoin. Bitcoin was officially "born" in 2009. Its foundation was laid by the so-called white paper titled "Bitcoin: A Peer-to-Peer Electronic Cash System" (2008), authored by Satoshi Nakamoto, a pseudonym for an individual or a group of individuals. In essence, the intention of its creator (or creators) was to solve the technical problem of so-called double-spending of money, aiming to avoid reliance on a third party or institution (such as a bank) and the consequent loss of privacy for its users, with the help of an algorithm called blockchain. Although Bitcoin can be viewed in continuity with movements such as crypto-anarchism and cypherpunk, whose roots trace back to the 1980s of the twentieth century, and although it is not the first cryptocurrency nor the first alternative to fiat money, Bitcoin is indeed the first cryptocurrency to have attracted broader attention in both public and academic discourse. This paper will shed light on the context in which Bitcoin was born and popularized, and will endeavor to defend the assumption that the popular imagination behind the Bitcoin currency is technoutopian. Finally, this paper will seek to demonstrate that the algorithm at the very core of Bitcoin is perceived not only as the fulfillment of an Enlightenment dream of a method itself as a non-cultural and supra-historical guarantor of objectivity (as the one) removed from politics, economy and ideology but also as a democratization method applicable to them all. Apart from the mentioned above, the paper concludes that Bitcoin is seen as the fulfillment of a modernist dream of efficient, formal, predictable, depersonalized bureaucracies in the context of the diminished legitimacy of centralized, hierarchically structured, sluggish, fallible, and abuse-prone economic and state institutions. The focus of trust shifts to technology: to an algorithm seen as self-regulating, efficient, free from ideology, subjective interests, and potential abuse, almost divinely infallible, decentralized, and democratic system that provides a group of individuals not only with the necessary tools to achieve their freedom and privacy, deprived from control and regulations, but also as a tool for reforming the political and economic system.

With the advancement of electronic and cardless payment technologies and the growth in identity thefts and frauds, it is important for merchants and vendors to be able to perform a retrospective verification on a previous transaction at any later time. However, some of the user’s identity credentials used as the basis of trust on these payment technologies may be changing over time, which could largely complicate or confuse the retrospective verifications. In this paper, we propose a self-sovereign dynamic digital identity scheme to address the above problem. We introduce the management and use of dynamic digital identity, which is created using the blockchain technology. The proposed scheme makes use of a combination of biometric traits and other identity attributes that could vary or evolve over time. Since the proposed dynamic identity allows tracing back to a previous version of the identity of the same individual via the blockchain, it can be used to retrospectively verify a previous transaction associated with a previous version of the identity.

“Blockchain” as the name suggests is the chain of blocks. It is the chunk of digital information (blocks) that are connected through the public databases (Chain). It is nothing but the newer version of file organisation. Blocks store digital information like actual record of any transaction, details of involve entities in the transaction, time stamps, and other metadata of the transactions. Blocks also have unique ids, which are known as hash. Blockchain technology is built using peer-to-peer networking. Anyone who is on network can access the blocks. There is no centralised community to control the blockchain. It is operated by miners, the peoples who lend their computing power to the network to solve the complex computation algorithm problems. These blocks are stored in multiple computers. Due to its distribution and decentralisation, the validation process is broadcast in nature, which provides it “the trusted approach”. Blockchain enables security and tamperproof capabilities for storing data and smart contracts. Any tampering of data attempted by a node or user in a block changes the hash of the block. The blockchain technology has the capability to face and provides the solution to fight with the problem of risk and security concern online. In 2008, a mysterious white paper titled “Bitcoin: A Peer to Peer Electronic Cash System”, by visionary Satoshi Nakamoto gave birth to the concept of blockchain. The chapter explains the structure of blockchain technology in detail and enlighten the aspects that make blockchain technology the secure concept of today's world.

Ongoing concerns with the security of health information, both from the perspective of the individual patient as well as health systems has led to increased attention being given to the potential role of blockchain technology in the secure storage of health information through encryption, the integration of diverse health record systems and the vesting of property and access rights to health data in the patient. While the security offered by blockchain technology has long been recognized in the finance sector with the emergence of a range of cryptocurrencies as a medium of exchange and store of value, demonstrating the value of blockchain technology in health management and health technology assessment has yet to be achieved. In this commentary, a number of questions are raised as to the potential value offered by blockchain technology as a complement to existing electronic medical record systems. Chief among these are: (i) the allocation of property rights as a necessary precondition for blockchain uptake; (ii) access and incentives for active as opposed to passive blockchain membership; (iii) monetization of blockchain access; (iv) capturing data from within the blockchain and the possibility of value added data; (v) the potential for blockchain platforms in formulary evaluations; (vi) the blockchain as a managed market for health data; and (vii) the role of intermediation in blockchain management.

Partially blind signature is an important technique in secure electronic cash system. Recently, Zhang et al. presented the first certificateless partially blind signature scheme and constructed an electronic cash system based on this scheme. They claimed that their certificateless partially blind signature scheme is secure in the random oracle model. However, in this paper, we demonstrate the scheme is not secure. Our attack indicates that a malicious KGC in the electronic cash system based on Zhang et al.'s certificateless partially blind signature can forge valid electronic coins without being detected by the bank. It will result in loss of the bank.

The urgency of this research is to increase efficiency, transparency and sustainability in increasingly complex and challenging agribusiness supply chains. The aim of this research is to develop an integrated system that combines IoT capabilities in collecting agricultural data in real-time, AI to analyze data and provide recommendations for action, as well as security and transparency guaranteed by blockchain technology. The method used is a mixed methods approach , this approach combines qualitative and quantitative elements to obtain a deeper understanding. A qualitative approach is used to gain a contextual perspective, while a quantitative approach is used to measure performance empirically. This research uses a case study design on a sensor-based agricultural monitoring system because of its ability to provide in-depth and holistic insights. The research population consists of users and stakeholders in sensor-based agricultural monitoring systems. The sample was selected purposively to cover various aspects of the supply chain. Data was collected through in-depth interviews, direct observation, surveys of system users and collection of sensor and transaction data from agricultural monitoring systems. The research results show that the integration of IoT, AI, and blockchain significantly improves operational efficiency in agribusiness supply chains. Implementation of this integrated system resulted in an increase in productivity of up to 22%, a reduction in pesticide use by 35%, an increase in water use efficiency by 30%, and a reduction in operational costs by 18%. Statistical analysis confirmed a strong positive correlation between the use of integrated technology and increased operational efficiency (R=0.85, p<0.01).