Not only the Internet has made global information and data exchange possible, but also put file synchronization and storage in the spotlight. A typical user has at least a few devices connected to the Internet and utilizes the most convenient one. Therefore, providing the ability to quickly access the updated data from any device is of an utmost importance. Shared access services grow in popularity, as they allow many people to work on the same data at one time. Shared access is provided by the majority of traditional centralized cloud data storage and file synchronization systems, but all they have security and availability issues. A centralized system is not able to ensure the appropriate level of security, reliability, and the possibility of a continuous operation. On the other hand, all of these criteria could be met by well-thought and structured decentralized blockchain-based data cloud storage granting confidentiality, decentralization, security, and other components necessary for an uninterrupted and safe operation.