Method and apparatus for recording of encrypted digital data

• US 20020048367A1
• Filed: 08/13/2001
• Published: 04/25/2002
• Est. Priority Date: 09/25/1997
• Status: Active Grant

• Current Assignee: Thomson Licensing SA (Vantiva SA)
• Original Assignee: Thomson Licensing SA (Vantiva SA)
• Inventors: Maillard, Michel
• Granted Patent: US 6,987,854 B2
• Time in Patent Office: Days
• US Class Current: 380/239
• CPC Class Codes: H04N 2005/91364 the video signal being scrambled
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 21/4405 involving video stream decryption
• CPC Class Codes: H04N 21/4408 involving video stream encryption, e.g. re-encrypting a decrypted video stream for redistribution in a home network
• CPC Class Codes: H04N 5/913 for scrambling ; for copy protection
• CPC Class Codes: H04N 7/163 by receiver means only
• 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 method of transmitting and recording digital data scrambled using a control word. The scrambled data is transmitted together with the control word, and the method includes encrypting the control word with a first key. The encrypted control word is transmitted and received, and then decrypted with a decoder that includes an equivalent of the first key. The control word is re-encrypted with a second key stored in a portable support device that is received by the decoder, and the portable support device may be used with any suitable decoder. The re-encrypted control word and the scrambled digital data are recorded on a digital recording medium.

An apparatus for transmitting and recording digital data scrambled using a control word. The scrambled data is transmitted together with the control word, and the apparatus includes a transmitter that encrypts the control word with a first key and transmits the encrypted control word. A decoder receives the encrypted control word and decrypts the control word. A portable support device including a second key is received by the decoder, and the decoder uses the second key to re-encrypt the decrypted control word and record the re-encrypted control word and the scrambled digital data on a digital recording medium. The portable support device may be used with any suitable decoder or digital recorder.

Claims

1_56. } A method of transmitting and recording digital data scrambled using a control word, the scrambled data being transmitted together with the control word, the method comprising:

encrypting the control word with a first key;

transmitting the encrypted control word;

receiving the encrypted control word and decrypting the control word with a decoder comprising an equivalent of the first key;

re-encrypting the decrypted control word with a second key stored in a portable support device adapted to be releasably received by the decoder, the portable support device adapted for use with a plurality of decoders; and

recording the re-encrypted control word and the scrambled digital data on a digital recording medium.

2_56. } The method of claim 1, wherein the portable support device comprises a smart card adapted to be releasably received by a smart card reader operatively coupled to the decoder.

3_56. } The method of claim 2, wherein the smart card comprises the equivalent of the first key.

4_56. } The method of claim 2, wherein the first key is separate from the second key that is stored on the smart card.

5_56. } The method of claim 2, wherein a single smart card is used to generate the re-encrypted control word for a plurality of recordings.

6_56. } The method of claim 2, wherein the smart card comprises credit units used to determine how many times the recorded digital data may be replayed.

7_56. } The method of claim 6, wherein the credit units are decremented after each playing of the recorded digital data.

8_56. } The method of claim 6, wherein the credit units are associated with a particular segment of the recording so that playing a selected segment of the recording decrements a selected number of credit units associated with that selected segment.

9_56. } The method of claim 6, wherein the credit units are decremented after the playing of any segment of the recording.

10_56. } The method of claim 1, wherein the portable support device comprises the digital recording medium, the second key being stored in a circuit disposed proximate the digital recording medium.

11_56. } The method of claim 10, wherein the circuit is embedded in a housing that encloses the digital recording medium.

12_56. } A method of transmitting and recording digital data scrambled using a control word, the scrambled data being transmitted together with the control word, the method comprising:

encrypting the control word with a first key;

transmitting the encrypted control word;

receiving the encrypted control word and decrypting the control word with a digital recorder comprising an equivalent of the first key;

re-encrypting the decrypted control word with a second key stored in a portable support device adapted to be releasably received by the digital recorder, the portable support device adapted for use with a plurality of digital recorders; and

recording the re-encrypted control word and the scrambled digital data on a digital recording medium operatively coupled to the digital recorder.

13_56. } The method of claim 12, wherein the portable support device comprises a smart card adapted to be releasably received by a smart card reader operatively coupled to the digital recorder.

14_56. } The method of claim 13, wherein the smart card comprises the equivalent of the first key used to decrypt the control word decrypting the control word and the digital data.

15_56. } The method of claim 13, wherein the first key is separate from the second key that is stored on the smart card.

16_56. } The method of claim 13, wherein a single smart card is used to generate the re-encrypted control word for a plurality of recordings.

17_56. } The method of claim 13, wherein the smart card comprises credit units used to determine how many times the recorded digital data may be replayed.

18_56. } The method of claim 17, wherein the credit units are decremented after each playing of the recorded digital data.

19_56. } The method of claim 17, wherein the credit units are associated with a particular segment of the recording so that playing a selected segment of the recording decrements a selected number of credit units associated with that selected segment.

20_56. } The method of claim 17, wherein the credit units are decremented after the playing of any section of the recording.

21_56. } The method of claim 12, wherein the portable support device comprises the digital recording medium, the second key being stored in a circuit disposed proximate the digital recording medium.

22_56. } The method of claim 21, wherein the circuit is embedded in a housing that encloses the digital recording medium.

23_56. } An apparatus for transmitting and recording digital data scrambled using a control word, the scrambled data being transmitted together with the control word, the apparatus comprising:

a transmitter that encrypts the control word with a first key and transmits the encrypted control word;

a decoder that receives the encrypted control word and decrypts the control word; and

a portable support device comprising a second key and adapted to be releasably received by the decoder, the decoder adapted to re-encrypt the decrypted control word using the second key and to record the re-encrypted control word and the scrambled digital data on a digital recording medium, the portable support device adapted for use with a plurality of decoders or digital recorders.

24_56. } The apparatus of claim 23, wherein the decoder comprises a digital recording device adapted to record the encrypted control word and digital data.