Title:
VIDEO CONTROL SYSTEM
Document Type and Number:
Japanese Patent JPH04223787
Kind Code:
A
Abstract:
PURPOSE: To provide a video control system for decoding the recording copy of an enciphered broadcasting or video image to control viewing. CONSTITUTION: A video program including a 1st field including both a random digital code enciphered by a code cryptographic key and program identification data and a 2nd field including an unviewable video signal previously converted from a viewable video signal by that random digital code is provided to a terminal by a video program means. The terminal transmits the program identification data to a central mechanism. The central mechanism retrieves one code cryptographic key at least corresponding to the program identification data and transmits that key to the terminal. The terminal receives the code cryptographic key, decodes the digital code enciphered by the code cryptographic key in the 1st frame and converts the unviewable video signal in the 2nd frame into the viewable video signal while using the deciphered random digital code.
Inventors:
SUTEIIBUN ESU UOOKAA
KURARENSU EMU SHIDOROO
MERUBIN JIEI TEAA
KURARENSU EMU SHIDOROO
MERUBIN JIEI TEAA
Application Number:
JP8737191A
Publication Date:
August 13, 1992
Filing Date:
March 28, 1991
Export Citation:
Assignee:
GTE LABORATORIES INC
International Classes:
H04H20/00; H04L9/08; H04L9/16; H04N7/16; H04N7/167; (IPC1-7): H04H1/00; H04L9/28; H04N7/167
Attorney, Agent or Firm:
Motohiro Kurauchi (1 outside)