Method for synchronizing program between multi-device using digital watermark and system for implementing the same

PURPOSE: A program synchronization method and a system for implementing the same between multiple devices using a digital watermark are provided to offer additional information related to a current watching time point or an additional service by matching an audio watermark with digital contents. CONSTITUTION: At least more than one device (320) receives an audio signal from digital contents played in a first device (320) and extracts a digital watermark from the audio signal. A watermark management server (400) inquires program name or additional information matched with the digital watermark from pre-stored data according to reception of the digital watermark extracted from more than one device and provides the inquired information to more than one device. [Reference numerals] (310) First device; (320) Second device; (400) Watermark maintenance server; (AA) N-screen; (BB) Digital content; (CC) Screen; (DD) Audio signal receiving part; (EE) Watermark extraction part; (FF) Transfer extracted data; (GG) Provide additional information about the name of a program