Book excerpt: The authors explore various aspects of information processing for the design of service systems, efficient management, secure storage, and transmission. In addition, the subline provides knowledge and practice in decentralized ICT technologies, including those based on blockchain. The aim of this book is to analyze and develop methods of building decentralized private databases without the presence of a trusted party, methods of data processing in encrypted form to ensure the confidentiality of information, and accessibility of the corresponding fragment of the original or transformed data. In this book it is also relevant to research methods and protocols routing in infocommunication networks, which provides load balancing in the network, and analysis of intrusion detection methods based on analysis of signatures and anomalies in network behavior (state changes) based on machine learning and fractal analysis methods.