The continuous evolution and widespread application of communication technology, network technology and computing technology have promoted the intelligent interconnection of all things and ubiquitous sharing of information. The cross-border, cross-system, and cross-ecosystem exchange of user data has become commonplace. At the same time, difficulties in the prevention of private information abuse and lack of protection methods have become global problems. As such, there is an urgent need to intensify basic theoretical research in this field to support the protection of personal information in a ubiquitously interconnected environment. The authors of this book proposed the concept, definition and research scope of privacy computing for the first time in 2015. This book represents their original and innovative scientific research achievement dedicated to privacy computing research, and systematically explains the basic theory and technology involved. It introduces readers to the connection between personal information and privacy protection, defines privacy protection and privacy desensitization, clarifies and summarizes the limitations of existing privacy-preserving technologies in practical information system applications, analyzes the necessity of conducting privacy computing research, and proposes the concept, definition and research scope of privacy computing. It comprehensively expounds the theoretical system of privacy computing and some privacy-preserving algorithms based on the idea of privacy computing. In closing, it outlines future research directions.