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Showing 5 results for Blockchain
Engineer Jamileh Bahri, Doctor Hamidreza Shayeghbrojeni,
Volume 8, Issue 1 (9-2019)
Abstract
Blockchain technology is a decentralized data structure based on a chain to the ledger of interconnected data blocks. Blockchain stores new blocks in the ledger without having to rely on intermediaries in a competitive or voting mechanism. Due to the chain structure or graph between each block and its previous block, it is impossible to modify blockchain data. Blockchain architecture provides trust in a peer-to-peer network through nodes on the network according to different consensus algorithms. In this article, we intend to describe the mechanism of each consensus-based, voting-based, and distant-oriented graph consensus algorithm.
Marjan Bahrololum, Zahra Ferdosi,
Volume 9, Issue 1 (8-2020)
Abstract
Today, cryptocurrencies in global payment systems have been proposed as a way to become independent of traditional banking and to get out of the control of banks and monetary policies of governments and reduce fraud in banking transactions and counterfeit them. In this paper, we create a comprehensive picture which includes the challenges of this field, and we analyze the results with a case study in both a quantitative and qualitative approach.
According on the characteristics the challenges in this picture are divided to three levels: technological, environmental, and governmental characteristics. Also, according to the results obtained from the use of cryptocurrencies in different countries, we able to identify most of the national cryptocurrency challenges for Iran.
Mahsa Rezaei, Sadegh Dorri Nogoorani ,
Volume 11, Issue 1 (9-2022)
Abstract
The development and use of electronic health records (EHR) have had remarkable impacts on human life, such as improvements in the quality of medical care, better research results, and enhancements in treatment methods. Despite these improvements, availability, security and privacy concerns have remained to be very important in this field. In this article, we propose a decentralized and distributed system for electronic health records management with the help of the blockchain technology and its potential benefits. In this system, patient information is stored in the cloud. Also, the real owner of the electronic records is the patient, and with the help of smart contracts and encryption, he/she controls how to access his/her health information. In the proposed solution, the problem of sharing and storing the patients’ keys has been solved with the help of smart contracts. In addition, we proposed solutions to special cases which are raised by transferring the control of the records to the patients such as permissions for underage patients, in emergency situations, and after the death of the patient. Comparison of the related works shows that the proposed system has solved the problems of competing systems while maintaining a high level of privacy.
Hadi Norouzi Cholcheh, Salman Niksefat,
Volume 12, Issue 2 (2-2024)
Abstract
Financial transactions in Bitcoin are stored in a distributed database called the block chain. All transactions are publicly available for all network nodes with the aim of transparency and the possibility of verifying the correctness. But this blockchain transparency feature, exploited by transaction analysis techniques, can lead to the violation of users’ privacy and the disclosure of their identities. Researchers have proposed various techniques such as transaction mixing or fair exchange with the aim of improving privacy in Bitcoin transactions. In this paper, we present a new mixing scheme that overcomes some of the weaknesses of previous schemes. Obviously, in the proposed scheme, users can mix different amounts of Bitcoin in each round of the protocol implementation, which leads to achieving the result in a shorter time and at a lower cost. Also, this scheme is more resistant to denial of service attacks by malicious users.
Dr Saeed Banaeian Far, Dr Maryam Rajabzadeh Asaar,
Volume 13, Issue 1 (8-2024)
Abstract
Data outsourcing to reliable centers for data maintenance, protection and accessibility is simple and low-cost and does not require physical infrastructure, hardware, software and human resources. However, real-world events and recent researches have shown that even reliable centers can abuse users' trust. For example, 1) make changes in the data they have, 2) delete them, or 3) make them temporarily/permanently unavailable. Data audit methods assure the data owners that the data recorded in the database is the same as the data sent by the user and reveals the changes made in it. But they only solve the first problem. In 2008, the introduction of a technology called blockchain, which had several attractive features such as transparency, immutability, and autonomy, caused the problems of many systems that needed the mentioned features to be solved. In this article, after reviewing and addressing several blockchain-based data auditing architectures and protocols, we review and analyze their general framework. Finally, we compare the reviewed works and specify some future horizons of this field.
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