INTERACTIVE BROADCAST SYSTEM AND METHOD FOR DETECTING ILLEGAL USER

摘要

PROBLEM TO BE SOLVED: To detect that a local clock of a user interface is illegally adjusted. SOLUTION: The interactive broadcast system has a central control system 2 that controls supply of an interactive application and a plurality of user interfaces 17-19. Each of the user interfaces 17-19 is respectively provided with an STB(Set Top Box) lock generating section 41 that is a means to generate a local clock signal and serves the interactive application to each user on the basis of a time denoted by each local clock signal. The central control system 2 distributes data of the interactive application to the user interfaces 17-19. Furthermore, the central control system 2 compares times when each user interface returns prescribed data and detects a shift of the local clock signals base on that to identify an illegal user.