CA1264848C - Key signal encryption and distribution system for controlling scrambling and selective, remote descrambling of television signals - Google Patents

Key signal encryption and distribution system for controlling scrambling and selective, remote descrambling of television signals

Info

Publication number
CA1264848C
CA1264848C CA 567574 CA567574A CA1264848C CA 1264848 C CA1264848 C CA 1264848C CA 567574 CA567574 CA 567574 CA 567574 A CA567574 A CA 567574A CA 1264848 C CA1264848 C CA 1264848C
Authority
CA
Canada
Prior art keywords
signal
key signal
key
unique
algorithm
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.)
Expired - Lifetime
Application number
CA 567574
Other languages
French (fr)
Other versions
CA1264848A (en
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
Priority claimed from US06/498,800 external-priority patent/US4613901A/en
Application filed filed Critical
Priority to CA 567574 priority Critical patent/CA1264848C/en
Application granted granted Critical
Publication of CA1264848A publication Critical patent/CA1264848A/en
Publication of CA1264848C publication Critical patent/CA1264848C/en
Anticipated expiration legal-status Critical
Expired - Lifetime 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

Abstract

KEY SIGNAL ENCRYPTION AND DISTRIBUTION SYSTEM FOR CONTROLLING SCRAMBLING AND SELECTIVE, REMOTE DESCRAMBLING OF TELEVISION SIGNALS ABSTRACT OF THE DISCLOSURE A system and method for scrambling and selectively descrambling television signals that are transmitted to subscribers' descramblers in a subscription television system. A working key signal is generated by processing an "initialization vector" signal in accordance with the DES algorithm upon the algorithm being keyed by either a common category key signal or some other key signal. A unique encryption keystream is generated by processing the initialization vector signal in accordance with the DES algorithm upon the algorithm being keyed by the working key signal. A television signal is scrambled in accordance with the unique encryption keystream to provide a scrambled television signal. A plurality of unique encrypted category key signals individually addressed to different selected subscribers' descramblers are generated by processing the initial common category key signal in accordance with the DES algorithm upon the algorithm being keyed by a plurality of different "unit key" signals unique to different selected descramblers. The scrambled television signal, the initialization vector signal, and the plurality of encrypted category key signals are broadcast to the descramblers. A corresponding tier of DES algorithms are employed at the descrambler to reproduce the encryption keystream; and the TV signal is descrambled in accordance therewith. Each descrambler has its unique unit key signal stored in a secure memory for use in reproducing the common catagory key signal when the descrambler is addressed by its unique encrypted cateaory key signal.
CA 567574 1983-05-27 1988-05-24 Key signal encryption and distribution system for controlling scrambling and selective, remote descrambling of television signals Expired - Lifetime CA1264848C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CA 567574 CA1264848C (en) 1983-05-27 1988-05-24 Key signal encryption and distribution system for controlling scrambling and selective, remote descrambling of television signals

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US06/498,800 US4613901A (en) 1983-05-27 1983-05-27 Signal encryption and distribution system for controlling scrambling and selective remote descrambling of television signals
CA000454444A CA1242793A (en) 1983-05-27 1984-05-16 Key signal encryption and distribution system for controlling scrambling and selective, remote descrambling of television signals
CA 567574 CA1264848C (en) 1983-05-27 1988-05-24 Key signal encryption and distribution system for controlling scrambling and selective, remote descrambling of television signals
US498,800 1990-03-26

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
CA000453865A Division CA1236103A (en) 1983-05-09 1984-05-08 1-sulfonyl-3-pyridinyl or pyrimidinyl ureas

Publications (2)

Publication Number Publication Date
CA1264848A CA1264848A (en) 1990-01-23
CA1264848C true CA1264848C (en) 1990-01-23

Family

ID=25670388

Family Applications (1)

Application Number Title Priority Date Filing Date
CA 567574 Expired - Lifetime CA1264848C (en) 1983-05-27 1988-05-24 Key signal encryption and distribution system for controlling scrambling and selective, remote descrambling of television signals

Country Status (1)

Country Link
CA (1) CA1264848C (en)

Also Published As

Publication number Publication date
CA1264848A (en) 1990-01-23

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Legal Events

Date Code Title Description
MKEX Expiry
MKEX Expiry
MKEX Expiry

Effective date: 20051004

Effective date: 20070123