Book excerpt: Online transaction has become an important part of the new economy and finance. At the same time, transaction payment fraud also presents an explosive trend.This unique compendium introduces risk control theories technologies of online transaction processes, and applies the traditional security technologies and advanced behavior authentication methods to the trustworthy guarantee of online transaction systems. The comprehensive volume also promotes the development of trustworthy online transaction theory and technologies.This useful reference text will benefit researchers in the field of computer science and technologies, as well as a research reference in the field of online transaction risk prevention and control.