Method and apparatus for scrambling and unscrambling data streams using encryption and decryption

• US 4,535,355 A
• Filed: 09/07/1982
• Issued: 08/13/1985
• Est. Priority Date: 06/23/1982
• Status: Expired due to Fees

• Current Assignee: Micro Design Limited
• Original Assignee: Micro Design Limited
• Inventors: Csanky, Peter H., Arn, Robert M., Waszek, Glen F.
• Primary Examiner(s): BUCZINSKI, STEPHEN C
• Application Number:
  US06/415,317
• Time in Patent Office: 1,071 Days
• Field of Search: 358/117, 358/122, 358/123, 178/22.17, 455/27, 375/2.1, 375/2.2, 179/1.5 FS
• US Class Current: 380/212
• 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

Methods and apparatus for scrambling and unscrambling a plurality of data streams having differing data, on a plurality of signal channels, are taught. The data streams may be television programs or other signal information, transmitted in a frame-by-frame manner with discrete synchronizing information, and where some of the data streams may be high priority such as pay-TV program material. All of the data streams are synchronized, an encryption key code is imposed on them, and a data package containing an identifier code for each data stream and a routing code is generated, so that each data stream is assigned at any instant of time to a specific one of the plurality of signal channels. The data package is encrypted in each data stream by being inserted at a specific place therein relative to the synchronizing information. At any authorized receiver the encryption key code is captured and used to decrypt the encrypted data package so as to decode the identifier and routing codes thereof, whereby a given data stream may be tracked no matter on which transmitted channel it appears at any instant of time. Several embodiments for controlling a local oscillator so as to track a given data stream, are taught.

Claims

1. A method of scrambling and unscrambling a plurality of data streams having differing data on a plurality of signal channels, where each data stream has discrete and recognizable synchronizing information contained therein, which is periodically or aperiodically transmitted, and where there are at least as many signal channels, each having a fixed carrier frequency, as there are differing data streams to be scrambled and unscramble;

comprising the steps of;

(a) synchronizing all of said plurality of data streams;

(b) generating an encryption key code and imposing said encryption key code onto said plurality of data streams;

(c) generating a data package which contains an identifier code for each data stream and a routing code by which said plurality of data streams are routed at any instant of time, so that each said data stream is assigned at that instant of time to a specific one of said plurality of signal channels;

(d) encrypting said data package in each of said data streams by inserting the same in said data stream at a specific place therein relative to said synchronizing information;

(e) transmitting said assigned routed data streams on their respective assigned signal channels;

(f) receiving said assigned routed data streams at any receiver equipped to receive and de-modulate the same;

(g) at any authorized receiver, capturing said encryption key code and utilizing said encryption key code to decrypt said encrypted data package so as to decode said identifier codes and said routing code; and

(h) utilizing said identifier codes and said routing codes so as to track a given data stream, no matter on which transmitted channel it appears at any instant of time.

2. The method of claim 1, where each of said data streams has a plurality of identifiable data stream categories which may or may not be mutually exclusive in any combination;

where access is permissible to any designated data stream category or combination of catagories by an access data key; and

where said encrypted data package includes, periodically or aperiodically, coded data stream category access data relevant to the category of the respective data stream being transmitted.

3. The method of claim 2, where at least one of said data streams has one video signal and other data.

4. The method of claim 3, where said other data may comprise mono or stereo audio signal data, conferencing data by which at least two remote locations are joined together for a multi-path exchange of data, or proprietary data to which limited access is desirable.

5. The method of claim 2, where all authorized receivers have a microprocessor having memory, and where a common encryption algorithm is written into all of said microprocessors'"'"' memories.

6. The method of claim 5, where each authorized receiver has a unique address.

7. The method of claim 5 or 6, where at least one of said data streams has one video signal to which a data stream category is assigned and where said data package for said data stream includes a data category code;

and where each receiver which is authorized to receive the category-identified data stream and has a preset access data key which recognizes and decodes the data stream category code for said category-identified data stream.

8. The method of claim 5 or 6, where at least one of said data streams has one video signal to which a data stream category is assigned and where said data package for said data stream includes a data category code;

and where each receiver which is authorized to receive the category-identified data stream has a preset access data key which recognizes and decodes the data stream category code for said category-identified data stream; and

where the category of a data stream being transmitted may, from time to time, be altered.

9. The method of claim 1, where said transmission of said assigned routed data streams on said signal channels is by way of direct broadcast satellite.

10. The method of claim 1, where said transmission of said assigned routed data streams on said signal channels is by way of terrestrial transmission or distribution techniques chosen from the group comprising co-axial cable distribution, fibre optics distribution, microwave distribution or transmission, VHF/UHF antenna transmission, or any combination thereof.

11. The method of claim 1, where said encrypted data packages are transmitted together with the synchronizing information for all of said synchronized data streams.

12. The method of claim 3, where said encrypted data package is transmitted on at least one vertical interval line of a single frame of said video signal.

13. The method of claim 1, where said encrypted data packages are transmitted within said synchronized data streams.

14. The method of claim 3, where said encrypted data package is inserted within at least some of the horizontal sync intervals of a frame of said video signal.

15. The method of claim 3, where said encrypted data package is carried on a sub-carrier transmitted together with said at least one data stream.

16. The method of claim 6, where said data packages are passed to said microprocessor at each unique receiver address.

17. The method of claim 16, where said receiver is, at any moment, set to track a given data stream;

and said data packages are fed to a signal processor which is adapted to strip said identifier and routing codes therefrom, and said identifier and routing codes are then passed, together with a synchronizing signal, to said microprocessor; and

said microprocessor controls the tracking of said given data stream by acting upon said identifier and routing codes so as to set said receiver to receive and de-modulate said given data stream at any one of said signal channels as said data stream signal is switched among said signal channels under control of said routing code.

18. Apparatus for scrambling a plurality of data streams having differing data on a plurality of signal channels, where each data stream has discrete and recognizable synchronizing information contained therein which is periodically or aperiodically transmitted, and where there are at least as many signal channels, each having a fixed carrier frequency , as there are differing data streams to be scrambled comprising:

means for generating data stream identifier codes, one for each data stream;

means for generating a signal for synchronizing all of said data streams;

means for selecting any of said data streams for transmission on any one of said signal channels;

means for generating a routing code;

means for generation an encryption key code and inserting the same in said data streams;

means for generating data packages by combining said synchronizing signal, said data stream identifier codes, said routing code, and any other data intended for encryption in each of said data streams;

means for encrypting said data packages in said data streams;

and means for transmitting said data streams with said encrypted data packages;

whereby said data streams are transmitted, at any instant of time, on their respective assigned signal channels according to said routing code and in a specific place relative to said synchronizing signal.

19. The apparatus of claim 18, where said encryption key code is included in said data packages.

20. The apparatus of claim 18, further including means for generating data stream category identifier codes, and for selectively imposing any specific data stream category code on any of said data streams;

and where said data stream category identifier codes are included in said data packages.

21. Apparatus for unscrambling a plurality of data streams having differing data, from a plurality of signal channels, where each data stream has discrete and recognizable synchronizing information which is periodically or aperidocially contained therein;

where said data streams contain an encryption key code, and each data stream has a data package encrypted therein at a specific place relative to said synchronizing information; and

where each data package includes data stream identifier codes and a routing code therefor;

comprising;

means for receiving said plurality of signal channels, and for selecting one of said data streams to be tracked;

tuning means for tuning to any one of said signal channels;

demodulating means for demodulating said any one of said signal channels;

means for capturing said encryption key code;

means for utilizing said encryption key code to decrypt said encrypted data package from said data stream on said signal channel being tuned and demodulated;

means for capturing said identifier codes and said routing code; and

means for controlling said tuner so that said tuner tracks said selected data stream from one signal channel to another as it is moved under control of said routing code.

22. The apparatus of claim 21, further including a microprocessor for controlling said tuner by decrypting said data stream according to an encryption algorithm contained in said microprocessor and resolved by said encryption key code.

23. The apparatus of claim 22, where said apparatus has a unique address which is written in a non-volatile random access memory of said microprocessor, and where said data packages periodically or aperiodically include an address code indicative of said address;

and including address code recognition means for recognizing the address code indicative of said unique address and upon such recognition enabling said microprocessor to store said data packages and to act upon them.

24. The apparatus of claim 23, where access to a selected data stream may be determined by the presence or absence in the data package for that selected data stream of an access data key code indicative of permitted access to that data stream;

and including an access data key enabler which permits said apparatus to track said selected data stream when enabled.

25. The apparatus of claim 24, where said access data key enabler may be preset by an access data key code included in a data package which may be received from time to time, and where said access data key code may set said access data key enabler to enable or disable the tracking of a selected data stream.

26. The apparatus of claim 22, 23 or 24, where any of said data streams may include a data stream category identifier code, and where said access data key enabler may be preset so as to enable or disable said microprocessor to control said tuner with respect to any selected data stream having a specific category identifier code as determined by said access data key code.

27. The apparatus of claim 22, 23 or 24, where said means for utilizing said encryption key code uses the presently transmitted encryption key code so as to permit decryption of the data streams being transmitted at that instant of time.

28. The apparatus of claim 22, 23 or 24, further comprising means for storing the presently transmitted encryption key code, and means for recognizing when said encryption key code is changed;

so that said means for utilizing said encryption key code is set for decrypting said data streams at the time that a change of encryption key code occurs, whereby decryption of said data streams is in accordance with the previously transmitted encryption key code.