Confirming the validity of a certificate and displaying content information

摘要

A method and a device for confirming a validity period of a certificate and a method and a device for displaying content information are provided. A certification error and displaying of wrong time information caused by wrong system time information can be prevented, and certification time can be reduced, by setting a system time for processing content on the basis of time information received from a content provider, confirming a validity period of a certificate for approval to access the content, and displaying content information.