On privacy in decentralized systems with tokens

A three-level model of a decentralized system is proposed, the level with protocols for the creation and validation of private transactions is highlighted. The main feature of ensuring the transaction privacy in decentralized systems with tokens is the need to validate the various conditions for the transaction content without access to it. Therefore, classes of non-classical (and non-standardized in the Russian Federation) cryptographic mechanisms, which are often used in decentralized systems with private transactions, are highlighted. The non-universality of the existing formal definitions of such systems is shown. Therefore, formalizing the transaction privacy property in the general case is an open problem.