WO2002019529A2 - Non-standard coding systems - Google Patents
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- WO2002019529A2 WO2002019529A2 PCT/IL2001/000801 IL0100801W WO0219529A2 WO 2002019529 A2 WO2002019529 A2 WO 2002019529A2 IL 0100801 W IL0100801 W IL 0100801W WO 0219529 A2 WO0219529 A2 WO 0219529A2
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Classifications
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- H—ELECTRICITY
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- H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
- H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
- H04N21/43—Processing of content or additional data, e.g. demultiplexing additional data from a digital video stream; Elementary client operations, e.g. monitoring of home network or synchronising decoder's clock; Client middleware
- H04N21/44—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs
- H04N21/4405—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs involving video stream decryption
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- H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
- H04N19/40—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
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- H04N21/2343—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements
- H04N21/234309—Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 or from Quicktime to Realvideo
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- H04N21/44—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs
- H04N21/4402—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs involving reformatting operations of video signals for household redistribution, storage or real-time display
- H04N21/440218—Processing of video elementary streams, e.g. splicing a video clip retrieved from local storage with an incoming video stream or rendering scenes according to encoded video stream scene graphs involving reformatting operations of video signals for household redistribution, storage or real-time display by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4
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- H—ELECTRICITY
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- H04N7/00—Television systems
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- 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 to coding and compression schemes in general, and in particular to multimedia content coding and compression schemes.
- DCT discrete cosine transform
- the lossy step might comprise simple quantization of the DCT transformed coefficients.
- the lossy step might comprise quantization of the outputs of the filter banks. In. general this lossy step is designed to be imperceptible to the viewer / listener and involves a transformation carried out in accordance with a model of the human visual and audio systems. For high compression ratios it is known in the art that this step will introduce noticeable artefacts to the content; the aim is to make the artefacts as unintrusive as possible.
- Syntactically code the resulting data This step utilizes information theory to efficiently represent the data, often using variable length coding techniques. The syntax will also include synchronization markers for error resilience, random access and so forth, as well as data indicating the actual choice of conversion parameters, resolution and so forth.
- compress and "encode”, in all of their grammatical forms, are used interchangeably throughout the present specification and claims to refer to encoding algorithms such as those described above.
- ISO/TEC 10918 Information technology Digital compression and coding of continuous-tone still images.
- ISO/TEC 11172-2 Information technology Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s. Video.
- ISO/IEC 11172-3 Information technology Coding of moving pictures and associated audio for digital storage media at up to about 1.5 Mbit/s. Audio.
- ISO/IEC 13818-2 Information technology Generic coding of moving pictures and associated audio information. Video.
- ISO/IEC 13818-3 Information technology Generic coding of moving pictures and associated audio information. Audio.
- Fig. 1 is a simplified block diagram illustration of a system for distributing valuable multimedia content in accordance with the prior art.
- a distribution headend 100 content, shown in Fig. 1 by way of example only as video content, is compressed (encoded) using a standard compression encoder 110.
- the standard compression encoder 110 may comprise an encoder conforming to any appropriate standard. Examples of appropriate standards include international standard such as MPEG- 1, MPEG-2, MPEG-4 and H.263. Other examples of appropriate standards include widely available proprietary standard such those as utilized by Windows Media or Real Networks.
- the content is then typically scrambled by a scrambler 120. It is intended in systems of this type that clients with the appropriate rights are able to descramble and view / render the content; those without such rights can not.
- DVB Digital Video Broadcasting
- CA Conditional Access
- Well known prior art rights management systems are generally proprietary.
- the client 130 comprises software running on an open platform, such as a personal computer (PC) or a similar device
- an unscrupulous user also known as a "hacker”
- a more sophisticated hacker may also be able to similarly attempt to steal the content even in a less open system.
- an obvious place to attempt to steal the content is at a point indicated by reference number 160, where the encoded content is passed, in non-scrambled form, between the descrambler 140 and the standard decoder 150. If the encoded content is captured at point 160 it can be easily distributed to every person that has a suitable standard decoder.
- the present invention seeks to provide improved apparatus and methods for protecting encoded content.
- the term “content”, in all of its grammatical forms, is used to refer to digital content of any appropriate kind, including, but not limited to, any one or combination of the following: audio content; video content; and content intended for interpretation or execution by a computer or similar device. It is appreciated that rich digital multimedia content, as described above, is a particular type of content; the term “content”, as used throughout the present specification and claims, is not limited to rich digital multimedia content. It is further appreciated that the present invention, in certain preferred embodiments thereof, may be particularly useful when used with rich digital multimedia content.
- the aim of security mechanisms protecting content should be to make the task of stealing the content at any stage as difficult as possible. It is further believed that protecting non-scrambled encoded content, said content being described above with reference to prior art Fig. 1, is an important part of the task of making stealing content as difficult as possible. It is a goal of the present invention, in some preferred embodiments thereof, to improve security mechanisms protecting content.
- a solution to counter the specific problem identified above with reference to Fig. 1, of stealing non-scrambled encoded content within the client 130 of Fig. 1, is for content to never appear in a standard compressed form within a client; this solution is achieved, in preferred embodiments of the present invention, by delivering the content in a non-standard bit stream to a non-standard decoder.
- reverse engineering may be thwarted by varying the non-standard decoder every so often.
- the non-standard decoder may be varied for each content item and / or for each user. In other words, if there are c content items and u users, there may potentially be up to c times u different non-standard decoders.
- a method for producing a non-standard coding scheme including providing a standard coding scheme including at least one syntax element, and modifying the at least one syntax element, thereby producing a non-standard coding scheme.
- a method for producing a non-standard coding scheme including providing a syntax-based standard coding scheme for receiving non-coded input and producing coded output, and modifying the coded output in accordance with a non-standard syntax modification scheme.
- a method for producing a plurality of related non-standard coding schemes including providing a syntax-based standard coding scheme for receiving non-coded input and producing coded output, and performing the following a plurality of times: modifying the coded output in accordance with a non-standard syntax modification scheme, thereby producing a plurality of related non-standard coding schemes.
- the first non-standard coding scheme is different from the second non-standard coding scheme.
- the first selected non-standard coding scheme is different from the second selected non-standard coding scheme.
- the modifying the coded output includes choosing a coded output modification.
- the choosing includes one of the following: pseudo-randomly choosing a coded output modification, and randomly choosing a coded output modification.
- a method for transforming content from a standard form coded in accordance with a standard coding scheme to content in a non-standard form coded in accordance with a non-standard coding scheme including providing content coded in a standard form in accordance with a standard coding scheme, the standard coding scheme including at least one syntax element, modifying the at least one . syntax element, thereby producing a non- standard coding scheme, and altering the content coded in the standard form in accordance with the non-standard coding scheme, thereby producing content encoded in a non-standard form in accordance with the non-standard coding scheme.
- a method for transforming content from a standard form coded in accordance with a standard coding scheme to content in a non-standard form coded in accordance with a non-standard coding scheme including providing content coded in a standard form in accordance with a standard coding scheme, the standard coding scheme including at least one syntax element, and altering the content coded in the standard form in accordance with a non-standard syntax modification scheme, thereby producing content encoded in a non-standard form in accordance with a non-standard coding scheme.
- the altering is performed a plurality of times, thereby producing a plurality of versions of content encoded in related non-standard forms in accordance with a plurality of non-standard coding schemes. Still further in accordance with a preferred embodiment of the present invention the altering includes choosing a coded content alteration.
- the choosing includes one of the following: pseudo-randomly choosing a coded content alteration, and randomly choosing a coded output alteration.
- a method for encoding content in a non-standard form in accordance with a non-standard coding scheme including providing content in non-encoded form, providing a standard coding scheme including at least one syntax element, modifying the at least one syntax element, thereby producing a non-standard coding scheme, and encoding the content in accordance with the non-standard coding scheme, thereby producing content encoded in a non-standard form in accordance with the non-standard coding scheme.
- the modifying and the encoding are each performed a plurality of times, thereby producing a plurality of versions of content encoded in related non- standard forms in accordance with a plurality of non-standard coding schemes.
- the modifying includes choosing a syntax modification.
- the choosing includes one of the following: pseudo-randomly choosing a syntax modification, and randomly choosing a syntax modification.
- the method also includes providing a decoder for decoding the content encoded in the non-standard form.
- the method also includes decoding the content encoded in the non-standard form.
- the method also includes scrambling the content coded in the non-standard form. Additionally in accordance with a preferred embodiment of the present invention the method also includes providing a descrambler for descrambling the content coded in the non-standard form.
- the method also includes descrambling the content coded in the non-standard form.
- the standard coding scheme includes one of the following: MPEG-1, MPEG-2, MPEG-4, and H.263.
- the standard coding scheme includes one of the following: the Windows Media coding scheme, and the Real Networks coding scheme.
- non-standard coding scheme encoding apparatus including a syntax-based standard coding scheme encoder for receiving non-coded input and producing coded output, and a syntax modifier for modifying the coded output in accordance with a non-standard syntax modification scheme.
- the syntax modifier is operative to modify the coded output in accordance with a plurality of related non-standard syntax modification schemes to produce a plurality of non-standard coded outputs.
- apparatus for producing a plurality of related non-standard coding schemes, the apparatus including a syntax-based standard encoder for receiving non-coded input and producing coded output, and an output modifier for performing the following a plurality of times: modifying the coded output in accordance with a non-standard syntax modification scheme, thereby producing a plurality of related non-standard coding schemes.
- apparatus for transforming content from a standard form coded in accordance with a standard coding scheme including at least one syntax element to content in a non-standard form coded in accordance with a non-standard coding scheme, the apparatus including a syntax modifier for modifying the at least one syntax element, thereby producing a non-standard coding scheme, and a content alteration device for altering the content coded in the standard form in accordance with the non-standard coding scheme, thereby producing content encoded in a non-standard form in accordance with the non- standard coding scheme.
- apparatus for transforming content from a standard form coded in accordance with a standard coding scheme including at least one syntax element to content in a non-standard form coded in accordance with a non-standard coding scheme, the apparatus including content alteration device for altering the content coded in the standard form in accordance with a non-standard syntax modification scheme, thereby producing content encoded in a non-standard form in accordance with a non-standard coding scheme.
- Fig. 1 is a simplified block diagram illustration of a system for distributing valuable multimedia content in accordance with the prior art
- Fig. 2 is a simplified block diagram illustration of a system for distributing valuable multimedia content, constructed and operative in accordance with a preferred embodiment of the present invention
- Fig. 3 is a simplified block diagram illustration of a system for distributing valuable multimedia content, constructed and operative in accordance with an alternative preferred embodiment of the present invention.
- FIGs. 4 - 9 are simplified flowchart illustrations of alternative preferred methods of operation of the present invention, in accordance with preferred embodiments thereof.
- FIG. 2 is a simplified block diagram illustration of a system for distributing valuable multimedia content, constructed and operative in accordance with a preferred embodiment of the present invention.
- the elements of the system of Fig. 2 may be implemented in any appropriate combination of hardware and software, as is well known in the art.
- the system of Fig. 2 is shown as operating on video content, it being appreciated that any appropriate type of content may be used.
- the system of Fig. 2 preferably comprises a distribution headend 200.
- the distribution headend 200 comprises a non-standard encoder 210.
- the non-standard encoder 210 is operative to perform functions similar to those of a standard encoder, such as the standard encoder 110 of Fig. 1, except that the encoding performed by the non-standard encoder 210 is non- standard.
- the non-standard encoder 210 may use basic encoder / decoder algorithms which are different from those used by any standard decoder. Examples of basic encoder / decoder algorithms, well known in the art, include algorithms for handling of DCT, intensity / color information, and so forth. It is appreciated that the "non-standardness" of the encoding performed by the non- standard encoder 210 may take any of a variety of forms; other examples are discussed in more detail below with reference to Fig. 3.
- the distribution headend 200 also preferably comprises a scrambler 220, which may comprise any appropriate scrambler well-known in the art, and which may be similar to the scrambler 120 of Fig. 1, described above.
- a scrambler 220 may comprise any appropriate scrambler well-known in the art, and which may be similar to the scrambler 120 of Fig. 1, described above.
- the system of Fig. 2 also preferably comprises a plurality or large multiplicity of clients; for the sake of simplicity of description and without limiting the generality of the foregoing, a single client 230 is shown in Fig. 2.
- the client 230 preferably comprises a descrambler 240, which may comprise any appropriate descrambler well-known in the art and compatible with the scrambler 220, in that the descrambler 240 is capable of descrambling scrambled encoded content produced by the scrambler 220. It is appreciated that any appropriate scrambling and descrambling mechanism may be used, and that the descrambler 240 may be similar to the descrambler 140 of Fig. 1.
- the client 230 also preferably comprises a non-standard decoder 250, operative to received non-standard encoded content produced by the descrambler 240 and to decode the non-standard encoded content, thereby producing content suitable for rendering or similar use.
- render is used, in all its grammatical forms, throughout the present specification and claims to refer to any appropriate mechanism or method of making content palpable to one or more of the senses. In particular and without limiting the generality of the foregoing, “render” refers not only to display of video content but also to playback of audio content. The operation of the system of Fig. 2 is now briefly described.
- Non-standard encoded content is encoded in accordance with a non-standard coding scheme by the non-standard encoder 210.
- Non-standard encoded content produced by the non-standard encoder 210 is received as input by the scrambler 220, which produces scrambled non-standard encoded content.
- the scrambled non-standard encoded content is sent, via any appropriate transmission apparatus (not shown) to the client 230.
- the received scrambled non-standard encoded content is input to and descrambled by the descrambler 240, producing non-standard encoded content.
- the client 230 preferably includes an appropriate rights management subsystem (not shown), such as a rights management subsystem as is well known in the art, for determining whether the client 230 has rights to render the content, and that the client 230 will preferably be prevented from rendering the content if the client 230 has no rights therefor.
- the non-standard encoded content produced by the descrambler 240 is input to the non-standard decoder 250, which produces non-encoded content, such as video, for rendering.
- a potential hacker of the system of Fig. 2 who attempts to steal content at a point indicated by reference number 260 will receive content which comprises non-standard encoded content.
- the hacker will need to be able to reverse engineer a non-standard decoder functioning similarly to the non-standard decoder 250 in order to make use of the stolen content.
- non-standard encoders 210 for such a scenario is believed to be complex and likely to be prohibitively difficult and / or expensive; this is especially believed to be so if the basic encoder / decoder algorithms, such as DCT, intensity / color information handling, motion handling and so forth, as described above, are modified from one non-standard encoder 210 to another non- standard encoder 210.
- basic encoder / decoder algorithms such as DCT, intensity / color information handling, motion handling and so forth, as described above, are modified from one non-standard encoder 210 to another non- standard encoder 210.
- the standard coding schemes were designed with hardware implementations in mind. Such an implementation assumes that the complete coding scheme - including syntax - is determined by the standard- defining documents.
- at least the syntax interpretation carried out by a non-standard decoder is preferably carried out by one or more changeable elements, typically implemented in software or firmware, that may be delivered in conjunction with the coded content.
- Fixed length codes are generally the simplest representation of a given syntactic field. In digital compression schemes a field could represent a simple number value, or something more complicated. For example, in MPEG-2 video, an eight bit fixed length field is used for the start code value. This value profoundly affects the interpretation of the subsequent bit stream.
- the start code value of hexadecimal 00 corresponds to a picture_start_code with the subsequent bits interpreted as a Picture Header.
- the start code value of hexadecimal B3 corresponds to the sequence_header_code with the subsequent bits interpreted as a Sequence Header.
- bit stream could be altered by assigning different, non-standard values to different start codes.
- the hexadecimal value 00 could be assigned to sequence_header_code
- the hexadecimal value B3 could be assigned to picture_start_code.
- the effect of such an approach would be to render viewing and/or other rendering of the bit stream on a standard MPEG-2 decoder impossible.
- syntactic translation for fixed length codes could be performed using static look up tables.
- algorithmic state machines might use algorithmic state machines to create non-static syntactic translations, allowing optimization for reverse-engineering resistant implementations in addition to the more standard criteria of code efficiency.
- variable length codes are often used to efficiently represent data.
- VLCs variable length codes
- the probabilities of occurrence for different symbols in an alphabet, or of different values in a data set are different.
- the letter "e” is much more common than the letter "q”.
- shorter code words are preferably used to represent the letter 'e' than the letter 'q'.
- Morse code is a well known example of the application of this technique and of the use of VLCs in general.
- a general term used in the art for the efficient coding of a data set based on its statistics is "entropy coding".
- Huffman encoding For efficient binary coding of data sets Huffman encoding, which is well known in the art, is often used.
- static Huffman codes or similar codes
- VLCs are often specified as fixed lookup tables for a given data set.
- the standard VLCs are generic to all content and the statistics used for them will be those gathered from a representative set of content; such standard VLCs implement static Huffman codes or similar codes.
- Changing the syntax of a VLC code is a more complex process than changing a fixed length code. Since the VLC table is generally optimized for representing the given data set efficiently, randomly changing the table is likely to result in an increased quantity of data to be sent.
- the suggested implementation would not alter the amount of binary data required to represent the content.
- An alternative preferred implementation could actually improve compression efficiency by reducing the amount of data to represent the content.
- the standard VLC tables are generic to all possible content; therefore, it may be possible to optimize the standard VLC tables further for specific instances of coded content. For example, it is possible that, in some cases, not all possible values of a given set of VLC tables will be used in the compression of given piece of content. Furthermore, the usage statistics of the values in the data set are likely to be different to the generic statistics used to define the standard VLC. Hence it is possible to utilize statistics gathered for a specific piece of content to generate a new VLC table that is optimized for that specific piece of content. For large pieces of content, such as video, it is possible that this approach could be applied to the compressed content as a whole, or to smaller batches such as, for example, batches each comprising a few seconds of video.
- entropy coding techniques in addition to VLC tables, are known in the art.
- a further example of an entropy technique is arithmetic coding, which is described, for example, in the following reference:
- a part of a macroblock may be sent in altered form, such as one or more of the following: complemented; negated; XOR with a fixed constant; XOR with a changeable constant.
- complemented negated
- negated XOR with a fixed constant
- XOR with a changeable constant XOR with a changeable constant.
- content transformations of the type described are comprised in the more general concept of syntax modification. It is appreciated that flexible approaches, such as that described above for improving the compression efficiency using VLCs, may be preferred for stored content where processing can be performed off line.
- Fig. 3 is a simplified block diagram illustration of a system for distributing valuable multimedia content, constructed and operative in accordance with an alternative preferred embodiment of the present invention.
- the system of Fig. 3 is similar to the system of Fig. 2.
- a headend 300 comprises, instead of the non-standard encoder 210 of Fig. 2, a standard encoder 305 and a syntax modifier 315.
- the syntax modifier 315 may be implemented in any appropriate combination of hardware and software.
- a client 330 comprising a descrambler 340 and a non-standard decoder 350, may be similar to the client 230, descrambler 240, and non-standard decoder 250 of Fig. 2, respectively.
- Standard encoded content produced by the standard encoder 305 is then post- processed by the syntax modifier 315 to change at least one syntax element of the syntax of the standard encoded content, thus producing non-standard encoded content, encoded in a non-standard form.
- the non-standard decoder 330 is required to view and/or render the content.
- the content is never available in a form that is easily distributed for viewing on standard decoders; for example, a hacker attempting to steal the content at a point indicated by reference number 360 will be faced with the same difficulties described above with reference to Fig. 2 and reference number 260.
- the preferred embodiment of Fig. 3 is believed to have several significant advantages over the preferred embodiment of Fig. 2:
- the changed syntax is different at least for every piece of content, such that a new non-standard decoder 350 is required for each content item; optionally, the changed syntax may also be different for each user, also as described above.
- Fig. 3 The preferred embodiment of Fig. 3 is believed to be preferred because a full unique encoding engine does not need to be developed for each variation in the syntax.
- third party encoding engines such as real time motion estimation for video, can be leveraged.
- the approach used in the preferred embodiment of Fig. 3 can be applied to existing compressed content, or to content compressed in real-time by specialized high-speed hardware
- FIGs. 4 - 9 are simplified flowchart illustrations of alternative preferred methods of operation of the present invention, in accordance with preferred embodiments thereof. The methods of
- Figs. 4 - 9 are believed to be self-explanatory with reference to the above discussion of Figs. 2 and 3.
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Abstract
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Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
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IL15446101A IL154461A0 (en) | 2000-08-31 | 2001-08-28 | Non-standard coding systems |
GB0304691A GB2382739B (en) | 2000-08-31 | 2001-08-28 | Non-standard coding systems |
AU2001282484A AU2001282484A1 (en) | 2000-08-31 | 2001-08-28 | Non-standard coding systems |
US10/344,656 US20040022389A1 (en) | 2001-08-22 | 2001-08-28 | Non-standard coding systems |
IL154461A IL154461A (en) | 2000-08-31 | 2003-02-13 | Non-standard coding systems |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
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US22950800P | 2000-08-31 | 2000-08-31 | |
US60/229,508 | 2000-08-31 | ||
GB0120442.9 | 2001-08-22 | ||
GBGB0120442.9A GB0120442D0 (en) | 2001-08-22 | 2001-08-22 | Non-standard coding systems |
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WO2002019529A2 true WO2002019529A2 (en) | 2002-03-07 |
WO2002019529A3 WO2002019529A3 (en) | 2002-08-08 |
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PCT/IL2001/000801 WO2002019529A2 (en) | 2000-08-31 | 2001-08-28 | Non-standard coding systems |
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AU (1) | AU2001282484A1 (en) |
GB (1) | GB2382739B (en) |
IL (1) | IL154461A0 (en) |
WO (1) | WO2002019529A2 (en) |
Citations (5)
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EP0778705A2 (en) * | 1992-07-21 | 1997-06-11 | Matsushita Electric Industrial Co., Ltd. | Scramble apparatus and descramble apparatus |
US5671278A (en) * | 1995-05-19 | 1997-09-23 | Pires; H. George | Video scrambling with variable function generator |
GB2316278A (en) * | 1996-08-09 | 1998-02-18 | Richard Steven Faria | Data Encryption |
US20010012365A1 (en) * | 2000-02-09 | 2001-08-09 | Klaus Gaedke | Method, encoding apparatus and decoding apparatus for protecting a data stream using encryption or for decoding a protected data stream using decryption |
EP1124376A1 (en) * | 2000-02-09 | 2001-08-16 | Deutsche Thomson-Brandt Gmbh | Method and apparatus for generating a data stream protected by encryption |
-
2001
- 2001-08-28 WO PCT/IL2001/000801 patent/WO2002019529A2/en active Application Filing
- 2001-08-28 IL IL15446101A patent/IL154461A0/en active IP Right Grant
- 2001-08-28 GB GB0304691A patent/GB2382739B/en not_active Expired - Fee Related
- 2001-08-28 AU AU2001282484A patent/AU2001282484A1/en not_active Abandoned
Patent Citations (5)
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EP0778705A2 (en) * | 1992-07-21 | 1997-06-11 | Matsushita Electric Industrial Co., Ltd. | Scramble apparatus and descramble apparatus |
US5671278A (en) * | 1995-05-19 | 1997-09-23 | Pires; H. George | Video scrambling with variable function generator |
GB2316278A (en) * | 1996-08-09 | 1998-02-18 | Richard Steven Faria | Data Encryption |
US20010012365A1 (en) * | 2000-02-09 | 2001-08-09 | Klaus Gaedke | Method, encoding apparatus and decoding apparatus for protecting a data stream using encryption or for decoding a protected data stream using decryption |
EP1124376A1 (en) * | 2000-02-09 | 2001-08-16 | Deutsche Thomson-Brandt Gmbh | Method and apparatus for generating a data stream protected by encryption |
Non-Patent Citations (3)
Title |
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ALATTAR A M ET AL: "Improved selective encryption techniques for secure transmission of MPEG video bit-streams" PROCEEDINGS 1999 INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (CAT. 99CH36348), PROCEEDINGS OF 6TH INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (ICIP'99), KOBE, JAPAN, 24-28 OCT. 1999, pages 256-260 vol.4, XP002197137 1999, Piscataway, NJ, USA, IEEE, USA ISBN: 0-7803-5467-2 * |
HERRE J ET AL: "Compatible scrambling of compressed audio" PROCEEDINGS OF THE 1999 IEEE WORKSHOP ON APPLICATIONS OF SIGNAL PROCESSING TO AUDIO AND ACOUSTICS. WASPAA'99 (CAT. NO.99TH8452), PROCEEDINGS OF 1999 WORKSHOP ON APPLICATIONS OF SIGNAL PROCESSING TO AUDIO AND ACOUSTICS, NEW PALTZ, NY, USA, 17-20 OCT. , pages 27-30, XP002197138 1999, Piscataway, NJ, USA, IEEE, USA ISBN: 0-7803-5612-8 * |
SPANOS G A ET AL: "Security for real-time MPEG compressed video in distributed multimedia applications" CONFERENCE PROCEEDINGS OF THE 1996 IEEE FIFTEENTH ANNUAL INTERNATIONAL PHOENIX CONFERENCE ON COMPUTERS AND COMMUNICATIONS (CAT. NO.96CH35917), CONFERENCE PROCEEDINGS OF THE 1996 IEEE FIFTEENTH ANNUAL INTERNATIONAL PHOENIX CONFERENCE ON COMPUTERS AND , pages 72-78, XP002197136 1996, New York, NY, USA, IEEE, USA ISBN: 0-7803-3255-5 * |
Also Published As
Publication number | Publication date |
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GB2382739A (en) | 2003-06-04 |
GB0304691D0 (en) | 2003-04-02 |
IL154461A0 (en) | 2003-09-17 |
AU2001282484A1 (en) | 2002-03-13 |
WO2002019529A3 (en) | 2002-08-08 |
GB2382739B (en) | 2004-10-20 |
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