The GUIDEC I was published in November 1997 by the International Chamber of Commerce (ICC) and then the GUIDEC was published in October 2000 in the name of GUIDEC II. The GUIDEC II is the next version of GUIDEC I. This paper examines the electronic authentication and certification practices under GUIDEC II in detail. Therefore, this paper can help parties concerned to understand electronic authentication and certification practices of electronic commerce. GUIDEC II maintains the content of GUIDEC I, but GUIDEC II adds some new definitions such as authenticating a message and explains the rights and responsibility of subscribers, certifiers, and relying parties in detail. The aim of the GUIDEC II is to enhance the ability of international business community to execute trustworthy digital transactions utilizing legal principles that promote reliable digital authentication and certification practice.