Scrambled broadcast system

• US 6,067,121 A
• Filed: 06/06/1996
• Issued: 05/23/2000
• Est. Priority Date: 06/07/1995
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Shigihara, Hideo
• Primary Examiner(s): Flynn, Nathan
• Assistant Examiner(s): Srivastava, Vivek
• Application Number:
  US08/659,530
• Time in Patent Office: 1,447 Days
• Field of Search: 348/730, 348/5.5, 348/460, 348/461, 348/474, 348/552, 348/10, 348/473
• US Class Current: 348/473
• CPC Class Codes: H04N 7/1675 Providing digital key or authorisation information for generation or regeneration of the scrambling sequence pseudo-random number generators in general G06F7/58

Abstract

A scrambled broadcast system including a scrambler having a first generator for generating a first redundancy added data by adding a first redundancy data which changes over time to a message data, a second generator for generating a second redundancy added data by adding a second redundancy data which is obtained by executing a predetermined operation to the first redundancy added data generated in tho first generator, and an encryptor for executing a predetermined encrypting processing to the second redundancy added data generated in the second generator, a descrambler having a restoring unit for restoring the second redundancy added data by decrypting the encrypted data output from the decryptor, a discriminator for discriminating whether the operation operated in the second generator is realized to the second redundancy added data restored in the restoring unit or not and discriminating the rightness of the message data which is made by removing the first and the second redundancy data from the second redundancy added data.

Claims

1. A television signal receiving apparatus for receiving a television signal to which control information for controlling a receiver terminal is multiplexed, comprising:

channel selecting means for selecting a channel on which the control information is multiplexed to the television signal in the state that a power switch of the apparatus is turned OFF; and

control means for cutting off power to said channel selecting means, said control means operating based on at least the control information multiplexed to the television signal.

2. A television signal receiving apparatus claimed in claim 1, wherein the control means controls the channel selecting means to select another channel when the control information is not obtained from a channel selected by the channel selecting means during a predetermined time.

3. A television signal receiving apparatus claimed in claim 1, wherein the control means controls the channel selecting means to select a following channel based on a preset order when the control information is not obtained from a channel selected in the channel selecting means during a predetermined lime.

4. A television signal receiving apparatus claimed in claim 1, wherein the control means starts to supply the power to the channel selecting means so as to execute a channel selecting operation using the channel selecting means in the state that a predetermined time has passed after cutting off the power to the channel selecting means.

5. A television signal receiving apparatus claimed in claim 1, wherein the control information contains data showing a transmission schedule of subsequent control information to be transmitted thereafter, and the control means records the transmission schedule contained in the control information and controls whether power is supplied to the channel selecting means based on the transmission schedule in the state that the control information is obtained from the channel selected in the channel selecting means.

6. A television signal receiving apparatus for receiving a television signal to which control information for controlling a receiver terminal is multiplexed, comprising:

channel selecting means for selecting a channel on which the control information is multiplexed to the television signal in the state that power starts being supplied from the exterior and in the state that a power switch of the apparatus is turned OFF; and

control means for cutting off power to said channel selecting means, said control means operating based on at least the control information multiplexed to the television signal,

wherein the receiver terminal receives external operating information in the state that the control information is obtained from a channel selected by said channel selecting means.

7. A television signal receiving apparatus for receiving a television signal to which control information for controlling a receiver terminal is multiplexed, comprising:

channel selecting means for selecting a channel on which the control information is multiplexed to the television signal in the state that operating information requesting a function which makes use of the data contained in the control information is inputted and in the state that a power switch of the apparatus is turned OFF; and

control means for cutting off power to said channel selecting means, said control means operating based on at least the control information multiplexed to the television signal,

wherein the receiver terminal executes the function in the state that the control information is obtained from the channel selected by said channel selecting means.