A source device and a method are provided for certifying and controlling A/V signals output from an A/V device through an output terminal of a digital visual interface (DVI) or a high definition multimedia interface (HDMI), using Digital Rights Management (DRM). The source device includes: a DRM module which decrypts encrypted multimedia contents included in DRM contents through certification of a source device, and generates a control message for controlling digital A/V channels connected between the source device and a sink device based on a DRM rule; an input controller which certifies A/V data input from a media decrypter, and outputs A/V data filtered according to a certifying result; an input interface which converts the filtered A/V data into pixel data and audio data; and a signal transmitter which encrypts and converts the pixel and audio data into high-speed serial digital A/V signals to be transmitted to the sink device.