Journal:Informatica
Volume 34, Issue 3 (2023), pp. 603–616
Abstract
The article presents the tax declaration scheme using blockchain confidential transactions based on the modified ElGamal encryption providing additively-homomorphic property. Transactions are based on the unspent transactions output (UTxO) paradigm allowing to effectively represent digital asset of cryptocurrencies in e-wallets and to perform financial operations. The main actors around transaction are specified, include money senders, receivers, transaction creator, Audit Authority (AA) and Net of users. A general transaction model with M inputs and N outputs is created, providing transaction amount confidentiality and verifiability for all actors with different levels of available information.
The transaction model allows Net to verify the validity of a transaction, having access only to encrypted transaction data. Each money receiver is able to decrypt and verify the actual sum that is transferred by the sender. AA is provided with actual transaction values and is able to supervise the tax payments for business actors. Such information allows to verify the honesty of transaction data for each user role.
The security analysis of the scheme is presented, referencing to ElGamal security assumptions. The coalition attack is formulated and prevention of this attack is proposed. It is shown that transaction creation is effective and requires almost the same resources as multiple ElGamal encryption. In addition to ElGamal encryption of all income and expenses, an additional exponentiation operation with small exponents, representing transferred sums, is needed. AA computation resources are slightly larger, since they have to be adequate for search procedures in the small range from 1 to ${2^{32}}-1=4294967295$ for individual money transfers.
Journal:Informatica
Volume 34, Issue 3 (2023), pp. 577–602
Abstract
Healthcare has seen many advances in sensor technology, but with recent improvements in networks and the addition of the Internet of Things, it is even more promising. Current solutions to managing healthcare data with cloud computing may be unreliable at the most critical moments. High response latency, large volumes of data, and security are the main issues of this approach. The promising solution is fog computing, which offers an immediate response resistant to disconnections and ways to process big data using real-time analytics and artificial intelligence (AI). However, fog computing has not yet matured and there are still many challenges. This article presents for a computer scientist a systematic review of the literature on fog computing in healthcare. Articles published in six years are analysed from the service, software, hardware, information technologies and mobility with autonomy perspectives. The contribution of this study includes an analysis of recent trends, focus areas and benefits of the use of AI techniques in fog computing e-health applications.
Pub. online:8 Feb 2021Type:Research ArticleOpen Access
Journal:Informatica
Volume 32, Issue 2 (2021), pp. 321–355
Abstract
Voting systems are as useful as people are willing to use them. Although many electronic election schemes have been proposed through the years, and some real case scenarios have been tested, people still do not trust electronic voting. Voting is not only about technological challenges but also about credibility, therefore, we propose a voting system focused on trust. We introduce political parties as active partners in the elections as a mechanism to encourage more traditional electors to participate. The system we propose here preserves elector’s privacy, it operates publicly through a blockchain and it is auditable by third parties.
Pub. online:20 Nov 2020Type:Research ArticleOpen Access
Journal:Informatica
Volume 32, Issue 2 (2021), pp. 397–424
Abstract
Blockchain is a decentralized database, which can protect the safety of trade and avoid double payment. Due to the widespread attention of researchers, the studies of this field have increased sharply in recent years. It is meaningful to reveal the development level and trends based on this literature. This paper adopts bibliometric methods to study the collaboration characteristics from the levels of author, institution and country. Furthermore, several kinds of collaboration networks and their centrality analysis are also presented, which not only display the development level and collaboration degree but also the evolution of author collaboration modes in different phases.
Pub. online:1 Jan 2019Type:Research ArticleOpen Access
Journal:Informatica
Volume 30, Issue 4 (2019), pp. 729–748
Abstract
In this paper, we present the progress of blockchain technology from the advent of the original publication titled “Bitcoin: A Peer-to-Peer Electronic Cash System,” written by the mysterious Satoshi Nakamoto, until the current days. Historical background and a comprehensive overview of the blockchain technology are given. We provide an up-to-date comparison of the most popular blockchain platforms with particular emphasis given to consensus protocols. Additionally, we introduce a BlockLib, an extensively growing online library on blockchain platforms collected from the various sources and designed to enable contributions from the blockchain community. Main directions of the current blockchain research, facing challenges as well as the main fields of applications, are summarized. We also layout the possible future lines in the blockchain technology development.