Digital currencies as a tool for developing the tax administration process: a comparison of the architecture of the digital ruble and foreign digital currencies[Цифровые Валюты Как Инструмент Развития Процесса Налогового Администрирования: Сравнение Архитектуры Цифрового Рубля И Иностранных Цифровых Валют]

Introduction. Digital currencies have quickly become one of the principles of digitalization of the finan-cial system. Following the emergence of a large number of scientific projects on digital currencies, the issues of creating reliable digital currencies have been implemented at the state level. Since digital currencies can influence not only monetary conversion, but also national sovereignty and strengthen settlements, the issue of their quality is becoming increasingly relevant, especially in the context of sanctions pressure and technological transformations. Research into various approaches to the archi-tecture of digital currencies can reveal them as a reliable tool for implementing financial and tax policies. Purpose. The authors aim to analyze how differences in blockchain architecture and the degree of centralization affect the efficiency, programmability and international compatibility of national digital currencies. As a specific research task, we compare the digital ruble with similar projects in other countries – China, Brazil, Sweden, Iran and the EU. The analysis focuses on architectural solutions as key factors determining not only technical characteristics, but also economic and political consequences. Materials and methods. The methodological basis of the study was a comparative institutional analysis, a case study of six national digital currency projects, and the interpretation of official technical documents and regulatory acts. Elements of parametric modeling were used to assess the impact of architectural solutions on transaction costs, settlement speed, and automation capabilities. Results. The authors established a relationship between the architectural solutions of the digital currency and the substantive characteristics of its application. It was found that centralized models, similar to the one used in the digital ruble, provide a high level of control, but limit cross-border scalability. Hybrid architectures, like those in China and Brazil, allow achieving a balance between control and flexibility. It is shown that architectural parameters directly affect economic efficiency, especially in the context of cross-border payments and programmable budget transfers. Conclusions. The article substantiates the thesis that the architecture of the digital currency blockchain is not a technical, but an economic and strategic variable. The choice of design determines not only the functionality, but also the integra-tion potential of national digital currencies. The CBDC architecture becomes a platform for the implementation of "invisible technologies" that ensure automatic compliance with the rules without the need for direct intervention. In this context, the digital ruble, while maintaining the current configuration, requires additional steps towards interoperability and expansion of functional interfaces for integration with both the national tax system and future international settlement circuits.