WO2006040708A2 - Procede et dispositif de cryptage de flux de donnees - Google Patents

Procede et dispositif de cryptage de flux de donnees Download PDF

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Publication number
WO2006040708A2
WO2006040708A2 PCT/IB2005/053237 IB2005053237W WO2006040708A2 WO 2006040708 A2 WO2006040708 A2 WO 2006040708A2 IB 2005053237 W IB2005053237 W IB 2005053237W WO 2006040708 A2 WO2006040708 A2 WO 2006040708A2
Authority
WO
WIPO (PCT)
Prior art keywords
data
encrypted
control data
audio
stream
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.)
Ceased
Application number
PCT/IB2005/053237
Other languages
English (en)
Other versions
WO2006040708A3 (fr
Inventor
Robert A. Brondijk
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.)
Koninklijke Philips NV
Original Assignee
Koninklijke Philips Electronics NV
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 Koninklijke Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Publication of WO2006040708A2 publication Critical patent/WO2006040708A2/fr
Publication of WO2006040708A3 publication Critical patent/WO2006040708A3/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/23—Processing of content or additional data; Elementary server operations; Server middleware
    • H04N21/234—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
    • H04N21/2347—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving video stream encryption
    • H04N21/23476—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving video stream encryption by partially encrypting, e.g. encrypting the ending portion of a movie
    • 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

Definitions

  • the present invention relates in general to the field of encryption of a data stream.
  • the present invention will be explained for the context of an MPEG data stream, but it is to be noted that this example is not intended to restrict the scope of the invention as the invention is applicable to many types of data stream.
  • an MPEG data stream contains different types of data in a multiplexed way.
  • the data are organized in data blocks having a body and a header, the payload data being contained in the body and the control data in the header.
  • the payload data are also jointly denoted the transport stream; the control data together are also denoted the program stream. It is further possible to distinguish between audio data and video data.
  • the control data relate, for example, to the timing of the data.
  • the data stream is typically compressed, and the control data contain data necessary for decompression.
  • the control data necessary for decompression is denoted "essential" control data; the remaining control data is denoted "non-essential" control data.
  • the entire data stream contains: - video payload data;
  • the data stream is typically encrypted in such a case, and the data stream needs to be decrypted before access is possible.
  • An apparatus receiving the data stream such as a television apparatus or a PC running a television application, typically comprises separate audio and video decoders (hardware), so the multiplexed data stream must be de-multiplexed to obtain the elementary audio and video data streams which can be provided to the separate audio and video decoders. Before de-multiplexing is possible, the data stream needs to be decrypted.
  • a first problem in this respect relates to the fact that this decryption process requires many computations. Especially in the case where it is desired to run an audio/video application (television application) on a PC, the processor needs to be very powerful and hence expensive if it is to be able to perform the decryption process.
  • a second problem in this respect relates to the fact that the PC needs to be aware of the decryption keys in order to perform decryption,. Transferring the decryption keys to the PC over public buses involves the risk that the decryption keys are intercepted.
  • a further problem in this respect relates to the fact that encryption tends to increase the number of bits to be transferred. It is a general objective of the present invention to overcome the above- mentioned problems.
  • the present invention is based on the understanding that a powerful encryption does not necessarily require that the entire data stream is encrypted.
  • only the control data is encrypted, while the payload data is left non-encrypted.
  • the receiving apparatus only needs to decrypt the control data. Since the amount of control data is much less than the amount of payload data, the calculation burden for the processor is substantially reduced.
  • only the essential control data is encrypted. This further reduces the calculation burden for the processor. Nevertheless, the encryption is still effective in that decompression is only possible after decryption. Without decryption no decompression is possible, and without decompression no rendering is possible.
  • figure IA is a block diagram schematically illustrating a prior art process for generating and transmitting an audio/video data stream
  • figure IB is a block diagram schematically illustrating a prior art process for receiving and decoding an encrypted audio/video stream
  • figure 2 is a block diagram schematically illustrating a process for generating an audio/video data stream in accordance with the present invention
  • figure 3 is a block diagram schematically illustrating a process for receiving a multiplexed encrypted audio/video stream in accordance with the present invention.
  • FIG. IA is a block diagram schematically illustrating a prior art process for generating an audio/video data stream.
  • Audio payload data APD and audio control data ACD are generated by an audio data source 1.
  • Video payload data VPD and video control data VCD are generated by a video data source 2.
  • An audio compression circuit 3 receives the audio payload data APD and performs a compression so as to provide compressed audio payload data CAD.
  • An audio multiplexing circuit 5 receives the compressed audio payload data CAPD and audio control data ACD and performs a multiplexing operation so as to provide a multiplexed audio stream MAS.
  • a video compression circuit 4 receives the video . payload data VPD and performs a compression so as to provide compressed video payload data CVPD.
  • a video multiplexing circuit 6 receives the compressed video payload data
  • CVPD and video control data VCD performs a multiplexing operation so as to provide a multiplexed video stream MVS.
  • An overall multiplexing circuit 7 receives the multiplexed audio stream MAS and the multiplexed video stream MVS and performs a multiplexing operation so as to provide a multiplexed audio/video stream MAVS.
  • An encryption circuit 8 receives the multiplexed audio/video stream MAVS and performs an encryption operation so as to provide an encrypted audio/video stream EAVS.
  • Figure IB is a block diagram schematically illustrating a prior art process for receiving this encrypted audio/video stream EAVS and deriving the original audio and video data therefrom.
  • a decryption circuit 11 receives the encrypted audio/video stream EAVS and performs a decryption operation so as to provide the decrypted yet multiplexed audio/video stream MAVS.
  • a demultiplexing circuit 12 receives the multiplexed audio/video stream MAVS and performs a demultiplexing operation so as to separately provide the multiplexed audio stream MAS and the multiplexed video stream MVS.
  • An audio processing circuit 13 receives the multiplexed audio stream MAS, separates the compressed audio payload data CAPD from the audio control data ACD, and performs a decompression process on the compressed audio payload data CAPD, based on the audio control data ACD, in order to provide the original audio payload data APD for further processing.
  • a video processing circuit 14 receives the multiplexed video stream MVS, separates the compressed video payload data CVPD from the video control data VCD, and performs a decompression process on the compressed video payload data CVPD, based on the video control data VCD, in order to provide the original video payload data VPD for further processing.
  • FIG. 1 is a block diagram schematically illustrating a process in accordance with the present invention for generating an audio/video data stream.
  • Audio payload data APD and audio control data ACD are generated by an audio data source 101.
  • An audio compression circuit 103 receives the audio payload data APD and performs a compression operation so as to provide compressed audio payload data CAPD.
  • the audio compression circuit 103 also provides audio decompression control data ADCD, i.e. control data essential for being able to decompress the compressed audio payload data CAPD.
  • An audio encryption circuit 105 receives the audio decompression control data ADCD and audio control data ACD and performs an encryption operation in order to provide encrypted audio control data EACD.
  • An audio multiplexing circuit 107 receives the compressed audio payload data CAPD and the encrypted audio control data
  • EACD and performs a multiplexing operation so as to provide a multiplexed encrypted audio stream MEAS.
  • Video payload data VPD and video control data VCD (relating, for example, to timing, video bit rate, frame rate, picture size, etc) are generated by a video data source 102.
  • a video compression circuit 104 receives the video payload data VPD and performs a compression operation in order to provide compressed video payload data CVPD.
  • the video compression circuit 104 also provides video decompression control data VDCD, i.e. control data essential for being able to decompress the compressed video payload data CVPD.
  • a video encryption circuit 106 receives the video decompression control data VDCD and video control data VCD and performs an encryption operation so as to provide encrypted video control data EVCD.
  • a video multiplexing circuit 108 receives the compressed video payload data CVPD and the encrypted video control data EVCD and performs a multiplexing operation in order to provide a multiplexed encrypted video stream MEVS.
  • An overall multiplexing circuit 109 receives the multiplexed encrypted audio stream MEAS and the multiplexed encrypted video stream MEVS and performs a multiplexing operation in order to provide a multiplexed encrypted audio/video stream MEAVS.
  • the audio encryption circuit 105 may be designed to encrypt all control data, i.e. the audio decompression control data ADCD as well as the audio control data ACD. It is sufficient, however, if the audio encryption circuit 105 encrypts only part of the control data. In a preferred embodiment, the audio encryption circuit 105 is designed to encrypt only the audio decompression control data ADCD and to leave the audio control data ACD un ⁇ encrypted. In this preferred embodiment, the audio control data ACD may by-pass the audio encryption circuit 105. The same applies, mutatis mutandis, to the video encryption circuit 106.
  • FIG. 3 is a block diagram schematically illustrating a process in accordance with the present invention for receiving the multiplexed encrypted audio/video stream MEAVS and deriving the original audio and video data therefrom.
  • a demultiplexing circuit 111 receives the multiplexed encrypted audio/video stream MEAVS and performs a demultiplexing operation in order to provide the compressed audio payload data CAPD, the encrypted audio control data EACD, the compressed video payload data CVPD, and the encrypted video control data EVCD separately of one another.
  • a first decryption circuit 113 receives the encrypted audio control data EADCD and performs a decryption operation in order to provide the audio control data ACD and the audio decompression control data ADCD.
  • An audio processing circuit 115 receives the compressed audio payload data CAPD and performs a decompression process, based on the audio decompression control data ADCD, in order to provide the original audio payload data APD and the original audio control data ACD for further processing.
  • a second decryption circuit 114 receives the encrypted video control data
  • a video processing circuit 116 receives the compressed video payload data CVPD and performs a decompression process, based on the video decompression control data VDCD, so as to provide the original video payload data VPD and the original video control data VCD for further processing.
  • the demultiplexing circuit 111 may be part of the central processing unit 117 of a PC, whereas the first decryption circuit 113 and the audio processing circuit 115, or the software implementing these functions, are part of an audio card 118, and the second decryption circuit 114 and the video processing circuit 116, or the software implementing these functions, are part of a video card 119.
  • the transfer of the compressed audio payload data CAPD from the CPU 117 to the audio card 118 and of the compressed video payload data CVPD from the CPU 117 to the video card 119 takes place over a public data bus 120.
  • the transfer of the control data necessary for decompression also takes place over this public data bus 120. However, this control data is still encrypted, so it is not possible to decompress the audio and video information on the basis of the information intercepted from the public bus.
  • the CPU 117 only needs to demultiplex the multiplexed data stream; and the demultiplexed data streams can be sent to the audio decoder and the video decoder, respectively, which are specialized pieces of hardware containing the decryption keys.
  • the advantages offered by the present invention are also obtained if part of the non-essential control data is encrypted. Compared with the prior art, furthermore, an improvement is already achieved if less than 100% of the payload data is encrypted. Furthermore, it is assumed in the above description that the control data are not compressed. However, the present invention is also applicable in cases where the control data is compressed.
  • the audio multiplexing circuit 107, the video multiplexing circuit 108, and the overall multiplexing circuit 109 are implemented as one combined circuit.
  • the data stream to be transferred may comprise audio and/or video data, this is not essential.
  • the present invention offers advantages in all cases where a data stream comprises compressed payload data and control data including control data necessary for decompression.
  • the present invention was explained above with reference to block diagrams, which illustrate functional blocks of the device according to the present invention. It is to be understood that one or more of these functional blocks may be implemented in hardware, where the function of such a functional block is performed by individual hardware components, but it is equally possible that one or more of these functional blocks are implemented in software, so that the function of such a functional block is performed by one or more program lines of a computer program or a programmable device such as a microprocessor, microcontroller, digital signal processor, etc.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)

Abstract

La présente invention concerne un procédé de transfert d'un flux de données crypté fait de données utiles comprimées et de données de commande. Les données de commande comprennent les données de commande de décompression nécessaires à al décompression des données utiles. En l'occurrence, les données utiles sont transférées comme données non cryptées, les données de commande de décompression l'étant comme données cryptées. Ce flux de données peut être de type audio ou vidéo, notamment MPEG.
PCT/IB2005/053237 2004-10-14 2005-10-03 Procede et dispositif de cryptage de flux de donnees Ceased WO2006040708A2 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
EP04105040.2 2004-10-14
EP04105040 2004-10-14

Publications (2)

Publication Number Publication Date
WO2006040708A2 true WO2006040708A2 (fr) 2006-04-20
WO2006040708A3 WO2006040708A3 (fr) 2006-07-13

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/IB2005/053237 Ceased WO2006040708A2 (fr) 2004-10-14 2005-10-03 Procede et dispositif de cryptage de flux de donnees

Country Status (2)

Country Link
TW (1) TW200627955A (fr)
WO (1) WO2006040708A2 (fr)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5805700A (en) * 1996-10-15 1998-09-08 Intel Corporation Policy based selective encryption of compressed video data
CA2405901C (fr) * 2001-10-26 2010-03-30 Sony Electronics Inc. Systeme de chiffrement partiel visant les paquets critiques
US7167560B2 (en) * 2002-08-08 2007-01-23 Matsushita Electric Industrial Co., Ltd. Partial encryption of stream-formatted media

Also Published As

Publication number Publication date
TW200627955A (en) 2006-08-01
WO2006040708A3 (fr) 2006-07-13

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