Restricted reception system

Abstract

Abstract PURPOSE:To simplify a transmitter and to improve the convenience and reliability of a restricted reception system by providing the system with a comparing means for comparing an additional key in a descrambled signal with a reproduced additional key and outputting a control signal corresponding to a compared result to control the output of the descrambled signal in accordance with the control signal outputted from the comparing means. CONSTITUTION:The transmission side 1 superposes an updatable additional key 12 to an unscrambled signal and the reception side 2 compares an additional key 24 reproduced by a distribution key 20 to be distriubted to a specific receiving subscriber and an individual key 23 inherent in a receiver with an additional key 25 extracted from a descrampled signal through a comparator 26 and controls the receiver based upon the compared result. Consequently, the transmitter or transmission data can be simplified while suppressing the illegal restoration of data by an illegal receiving person and flexible addressing can be attained.

Inventors

• 👤 Yoshikazu Kotaka
• 👤 小鷹　義和
• 👤 Ikuo Shimizu
• 👤 清水　郁生

Bibliographic Details