At the same time as the 2008 financial crisis, the world faced the idea of decentralizing "money," and the first decentralized currency based on pure computer credit was introduced in 2009. This idea, which was also raised by Hayek in the 1970s, created various forms of "private money" in the economy. Meanwhile, the Islamic State's approach to these types of currencies has been a topic of discussion. In this study, we used the thematic analysis method to examine the Islamic State's confrontation with proof-of-work cryptocurrency in accordance with its duties. We identified the proportion of cryptocurrencies with attention to the decentralized characteristic of the right to create it, using six tasks of justice: preserving the value of national currency, independence, and economic security, market stability, employment, and taxation. As a result of this study, we concluded that the government should address this phenomenon proactively and in a decentralized manner while considering the risks and opportunities it presents. Initially, cryptocurrencies posed a potential threat to the government's monetary governance, but they also have opportunities. The government's approach to mining should be informed by considerations of energy security and other sectors, from consumer education to targeted restrictions. This suggests that the government's flexible approaches can adapt to future market developments, and that extensive bans on technological attractions are ineffective. Targeted restrictions can be implemented to address necessary challenges.

The prominent characteristic of the third millennium and the age of information and communication of technology (ICT) can be looked speed and diversity in advances and innovations. It is a matter that the cognition of the technological phenomena and activism to make them legal is consistently lagging some steps behind the evolutions. One of the most important examples of such phenomena is cryptocurrencies. After more than one decade after issuance and introduction of cryptocurrencies, they include more strategical vacuums in respect to the regulation and adjustment. Undoubtedly in the formation of such sphere the unfamiliarity of the features, applications and the emerging of this technology background of this technology means blockchain have had a prominent role. With applying an active and dynamic approach some states have tried to adopt policy in this field; an approach which is a sign of a dynamic activism in dealing with cryptocurrencies. In this regard one of the most important and controversial aspect of these interventions in the field of cryptocurrencies is the criminal intervention via criminalization around some dangers of this technology, a problem needs to be justified because of the limitation of freedom through it, the necessities of criminalization in the field of cryptocurrencies should be cognized. According to this, the following research with analytic-descriptive method examines the necessities of criminalization and forms of offences in the area of cryptocurrencies.

Although it takes the equality of states as an international principle, the international system is an unequal system in which power is essential. Unilateral sanctions, such as those of the United States government that violates international law, are examples of this inequality. Governments are always looking for ways to bypass these unjust sanctions. The formation of cryptocurrencies as a means of facilitating financial transfers beyond the control of regulators raises the question of whether the specific features of this means could also serve as a means of bypassing sanctions. And will cryptocurrencies be able to end the United States dollar’s dominance of international trade? In response, while such a capability exists in theory, and blockchain technology and cryptocurrency, as one of its essential products, can transact financially away from the dominance of the global economic system, this does not imply that the technology has the full potential to bypass the global financial system. Because the application of this technology in bilateral state interactions necessitates political will, and only a few countries worldwide have embraced this.

Since 2007, with the introduction of Bitcoin based on blockchain technology, a new generation of electronic money has emerged that can circulate among different people and be used in the cycle of economic exchanges. Decentralization, cross-border nature, anonymity of users, anonymity and complexity of processes of interception and identification of participants, encryption and irreversibility of transactions are the features that draw the attention of criminals to the use of cryptocurrencies in criminal activities. The purpose of this research is to describe and explain the crimes related to the field of cryptocurrencies and to identify the legal challenges of these crimes. This research is applied in terms of type and purpose, and descriptive-analytical in terms of method, and it was conducted in an exploratory manner. To collect information, library resources (for the theoretical part), and questionnaires and semi-structured interviews (for the practical part) have been used. The statistical population of this study consists of experts and senior managers who are active in this field, 100 people who were selected by combined snowball and targeted sampling, and after interviewing 9 managers, the data was analyzed by Thematic have been analyzed. By examining the points of view obtained from senior managers, professors and experts active in the field of cryptocurrencies in FATA police, who were selected in a purposeful way, and also by examining library resources, the challenges of cryptocurrency crime proceedings were enumerated, extracted and analyzed. . The result of this research shows that ambiguity in the nature of cryptocurrencies, how to apply laws and regulations on cryptocurrencies, how to identify and detect crimes, seize and confiscate and store cryptocurrencies, use of electronic evidence and determination of jurisdiction are among the main challenges in the proceedings of related crimes. With cryptocurrencies, judicial authorities and police should pay attention to it and provide basic solutions in this regard. According to the findings of the research and the hypothesis test, the information related to the legal challenges of cryptocurrency crimes is suitable and because the values (t value) of all the components of the legal challenges area based on the path coefficients model are more than 1. 96, so all the variables is approved.

In recent years a new type of tradable assets appeared, generically known as cryptocurrencies. Some of them are widespread and global. This paper examines the volatility of cryptocurrencies, with particular attention to their potential long memory properties. Three different long-memory methods (R/S analysis, fractional integration and fractional GARCH extensions) are used to analyze it in the case of the four main cryptocurrencies (BitCoin, Ethereum, LiteCoin and Ripple) over the sample period January 2013–,November 2019. Our results are twofold. First, R/S method is prone to detect long memory whereas the findings of ARFIMA and GARCH type models indicate that in the case of two examined cryptocurrencies (BitCoin and Ethereum), long memory exist (there is a positive correlation between its past and future values). Such predictability represents evidence of market inefficiency in their markets: trend trading strategies can be used to generate abnormal profits in these markets. Although our findings show that returns of Litecoin and Ripple don’, t have a significant long memory.

One of the legal challenges of cryptocurrencies- called “revolutionary money circle”- is its use in money laundering which in spite of trade prevalence, is a hurdle against cryptocurrencies acceptance by Legislature. In this study, we’ve tried to answer the questions about "cryptocurrency role in money laundering " and "methods of cryptocurrency money laundering " through a comprehensive analysis. They have been included in the money laundering process based on their inherent features such as “facilitation” and “diversification”. In this way, “coin mixers; illegal currency exchange; cryptocurrency ATMs; pre-payment cards; gambling websites” work as tools for cryptocurrency money laundering. Thus, along with criminal codes, governments and different organizations have played active roles and have established rules that require financial service providers to identify customers. Also, FATF has emphasized, in its updated guidelines, that cryptocurrency service providers must be regulated by money laundering and terrorism financing fighting policies. It's obvious that the implementation of such regulations by legal regimes’ support and development of solutions such as “customer identification” can contribute to solve the problem of anonymity of trading parties. Therefore, in money laundering fighting process, the problem is more about tracking technologies rather than legal gaps. In conclusion, the government should be equipped with the required technology.

Recently, many investors have become interested in investing in cryptocurrency market. Investing in an asset carries a lot of risk and may bankrupt the investor. The main way to control this risk is portfolio diversification. In this paper, we will investigate the effect of portfolio diversification by adding cryptocurrencies to the portfolio. We evaluate the performance of seven risk-based portfolio optimization strategies. these strategies are the minimum variance, inverse volatility, L2-norm constrained minimum variance, L2-norm constrained maximum decorrelation, risk parity portfolio and maximum diversification. Our portfolios consist of three markets stocks including, Tehran Stock Exchange, Commodities and Cryptocurrencies. Also, due to the fact that the cryptocurrency market has gained a significant attraction among investors, we will examine the positive and negative effects of adding the five selected currencies, simultaneously and separately to the base portfolio, which is Tehran Stock Exchange-Commodities portfolio. We investigate that whether adding cryptocurrencies to a stock portfolio can be considered as a tool to improve a risk-based portfolio. After analyzing portfolios, the best portfolio in each strategy and the best strategy in each portfolio are introduced from the aspects of risk, return and Sharpe ratio, and finally we have concluded that entering the cryptocurrency market in most of the strategies lead to an overall increase in the return, while the approach is to minimize the risk of the portfolio. So, it can be concluded that if the main goal is to build a more diversified portfolio, better outcome can be obtained for the investor considering the return gained.

The clustering of cryptocurrencies as an emerging field in investment management is the main topic of this research. Applying the information-based distance matrices, we clustered the 30 most valuable cryptocurrencies. Then, we identified the most influential clustering by the concept of Minimum Spanning Tree (MST) and the centrality measures of graph theory. A second-order clustering, which is defined as the clustering of hierarchical clusterings, was applied to cluster 56 dendrograms. Using the most influential clustering, we identified the main clusters of cryptocurrencies and sub-clusters. The results showed that the clustering composition of cryptocurrencies changed at the period I (before COVID-19) and II (pandemic time).

Background and Aim: Dark web and digital currencies were introduced for providing better services to communities. But the pseudo-anonymous nature of digital currencies, along with the anonymity and concealment of transactions on the Dark Web, has led to the interest of cybercriminals in both of these topics and the abuse for criminal purposes. The study and analysis of the combination of these two tools together can be used for informing, managing, and developing preventive actions to reduce the growth of cybercrimes. Therefore, the purpose of this study is to investigate and analyze the role of cryptocurrencies in facilitating the commission of cybercrimes in the dark web. Method: This is a descriptive-analytical study for applied purposes and the data were derived through the library research method.Findings: The Dark Web provides a haven for criminal activities, and due to unresolved challenges in the field of cryptocurrencies, including implementation of laws and regulations, detection of crimes, security of assets, and similar issues, the growth and spread of criminal activities in the Dark Web is provided.Conclusion: While officers improve their cyber technical capabilities and expertise; Criminals also use the slightest vulnerability of digital currencies to expand their activities. Therefore, it seems that formal laws, improvement of information sharing between law enforcement authorities and financial institutions, as well as the expansion of international cooperation, are the necessities for managing the prevention of cybercrime growth.