JPS5639685A - Decoding system - Google Patents

Decoding system

Info

Publication number
JPS5639685A
JPS5639685A JP11424279A JP11424279A JPS5639685A JP S5639685 A JPS5639685 A JP S5639685A JP 11424279 A JP11424279 A JP 11424279A JP 11424279 A JP11424279 A JP 11424279A JP S5639685 A JPS5639685 A JP S5639685A
Authority
JP
Japan
Prior art keywords
code
enable
decoder
key
arithmetic
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
JP11424279A
Other languages
Japanese (ja)
Other versions
JPS622756B2 (en
Inventor
Tsutomu Kanai
Masataka Okada
Toshimi Shiun
Yoichi Iwasaki
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Faurecia Clarion Electronics Co Ltd
Original Assignee
Clarion Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Clarion Co Ltd filed Critical Clarion Co Ltd
Priority to JP11424279A priority Critical patent/JPS5639685A/en
Publication of JPS5639685A publication Critical patent/JPS5639685A/en
Publication of JPS622756B2 publication Critical patent/JPS622756B2/ja
Granted legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/16—Analogue secrecy systems; Analogue subscription systems
    • H04N7/167—Systems rendering the television signal unintelligible and subsequently intelligible
    • H04N7/1675—Providing digital key or authorisation information for generation or regeneration of the scrambling sequence

Landscapes

  • Engineering & Computer Science (AREA)
  • Computer Security & Cryptography (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)

Abstract

PURPOSE:To prevent the leakage of a secret by concealing an enable code by externally inputting a key code and then by obtaining the enable code by arithmetic with an ID code set in a decoder. CONSTITUTION:When a key code is inputted to the decoder, an enable code can be obtained by arithmetic with a characeteristic ID code set in the decoder. Multiplexer circuits IC1 and IC2 determine one of inputs by selecting an address. Key code K and the ID code are inputted to circuits IC1 and IC2, whose outputs are half-added by half-adding logic circuit G and enable code E is lead out of its output. In this case, the key code is so set that the obtained enable code E will be in common to all decoders. Thus, the enable code is concealed to prevent tapping and robbery.
JP11424279A 1979-09-07 1979-09-07 Decoding system Granted JPS5639685A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP11424279A JPS5639685A (en) 1979-09-07 1979-09-07 Decoding system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP11424279A JPS5639685A (en) 1979-09-07 1979-09-07 Decoding system

Publications (2)

Publication Number Publication Date
JPS5639685A true JPS5639685A (en) 1981-04-15
JPS622756B2 JPS622756B2 (en) 1987-01-21

Family

ID=14632828

Family Applications (1)

Application Number Title Priority Date Filing Date
JP11424279A Granted JPS5639685A (en) 1979-09-07 1979-09-07 Decoding system

Country Status (1)

Country Link
JP (1) JPS5639685A (en)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58501982A (en) * 1981-11-19 1983-11-17 コミユニケ−シヨンズ・サテライト・コ−ポレ−シヨン Protection device for subscriber satellite television encryption
US4494143A (en) * 1982-03-29 1985-01-15 Rca Corporation Television descrambler with security plug having folded flexible printed circuit board providing tier tag memory
JPS6195688A (en) * 1984-10-12 1986-05-14 ジヨン　デイヴイツド　ヴイードマー Pay television system having security function
US4802214A (en) * 1982-04-23 1989-01-31 Eagle Comtronics, Inc. Method and apparatus for identifying and rendering operative particular descramblers in a television signal scrambling system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS58501982A (en) * 1981-11-19 1983-11-17 コミユニケ−シヨンズ・サテライト・コ−ポレ−シヨン Protection device for subscriber satellite television encryption
EP0094423A1 (en) * 1981-11-19 1983-11-23 Communications Satellite Corp A security system for sstv encryption.
JPH06125554A (en) * 1981-11-19 1994-05-06 Communications Satellite Corp <Comsat> Protective method for encoding of sunscribed satellite television
US4494143A (en) * 1982-03-29 1985-01-15 Rca Corporation Television descrambler with security plug having folded flexible printed circuit board providing tier tag memory
US4802214A (en) * 1982-04-23 1989-01-31 Eagle Comtronics, Inc. Method and apparatus for identifying and rendering operative particular descramblers in a television signal scrambling system
JPS6195688A (en) * 1984-10-12 1986-05-14 ジヨン　デイヴイツド　ヴイードマー Pay television system having security function

Also Published As

Publication number Publication date
JPS622756B2 (en) 1987-01-21

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