EP0793880A1 - Manipulation de paquets de donnees - Google Patents

Manipulation de paquets de donnees

Info

Publication number
EP0793880A1
EP0793880A1 EP96917632A EP96917632A EP0793880A1 EP 0793880 A1 EP0793880 A1 EP 0793880A1 EP 96917632 A EP96917632 A EP 96917632A EP 96917632 A EP96917632 A EP 96917632A EP 0793880 A1 EP0793880 A1 EP 0793880A1
Authority
EP
European Patent Office
Prior art keywords
messages
shared
signal
sub
emm
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.)
Withdrawn
Application number
EP96917632A
Other languages
German (de)
English (en)
Inventor
Ian Kenneth Stuchburry
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
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, Philips Electronics NV filed Critical Koninklijke Philips Electronics NV
Publication of EP0793880A1 publication Critical patent/EP0793880A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/04—Network architectures or network communication protocols for network security for providing a confidential data exchange among entities communicating through data packet networks
    • H04L63/0428—Network architectures or network communication protocols for network security for providing a confidential data exchange among entities communicating through data packet networks wherein the data content is protected, e.g. by encrypting or encapsulating the payload
    • H04L63/0457—Network architectures or network communication protocols for network security for providing a confidential data exchange among entities communicating through data packet networks wherein the data content is protected, e.g. by encrypting or encapsulating the payload wherein the sending and receiving network entities apply dynamic encryption, e.g. stream encryption
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/10—Network architectures or network communication protocols for network security for controlling access to devices or network resources
    • 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]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/41—Structure of client; Structure of client peripherals
    • H04N21/418—External card to be used in combination with the client device, e.g. for conditional access
    • H04N21/4181—External card to be used in combination with the client device, e.g. for conditional access for conditional access
    • 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]
    • H04N21/40—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
    • 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]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/45—Management operations performed by the client for facilitating the reception of or the interaction with the content or administrating data related to the end-user or to the client device itself, e.g. learning user preferences for recommending movies, resolving scheduling conflicts
    • H04N21/462—Content or additional data management, e.g. creating a master electronic program guide from data received from the Internet and a Head-end, controlling the complexity of a video stream by scaling the resolution or bit-rate based on the client capabilities
    • H04N21/4623—Processing of entitlement messages, e.g. ECM [Entitlement Control Message] or EMM [Entitlement Management Message]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N7/00—Television systems
    • H04N7/16—Analogue secrecy systems; Analogue subscription systems
    • H04N7/162—Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing
    • H04N7/163—Authorising the user terminal, e.g. by paying; Registering the use of a subscription channel, e.g. billing by receiver means only
    • 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
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L2463/00—Additional details relating to network architectures or network communication protocols for network security covered by H04L63/00
    • H04L2463/101—Additional details relating to network architectures or network communication protocols for network security covered by H04L63/00 applying security measures for digital rights management

Definitions

  • the present invention relates to systems for receiving and handling packetised data and particularly, but not exclusively, to conditional access reception systems for handling encrypted broadcast data.
  • conditional access systems data reception (for example of television pictures) is restricted to a specific subset of receivers, such as subscribers to a satellite movie channel.
  • the data is transmitted in scrambled form and requires particular codes or 'keys' to enable it to be descrambled. These codes may be held by a subscriber or they may be transmitted in encrypted form along with the scrambled data and require the user to present a particular form of entitlement to allow decryption of the codes and hence descrambling of the data.
  • An example of an encrypted broadcast system is described in European patent application EP-A-0 641 103, which describes the application of probabilistic determination to the generation of secure codes for subscriber and supplier.
  • a problem with encrypted broadcast and other data handling systems occurs where the transmitted data is in the form of a header followed by a succession of data packets and the receiver is required to analyse the header to determine which of the following packets is actually required.
  • This can be a particular problem with domestic satellite broadcast systems where the user will typically have a satellite receiver with integral descrambler coupled to a separate smartcard reader with decryptor: the descrambler passes the header to the decryptor for analysis and the decryptor responds with an identification code for the packets required. If the first packet following the header is one of those required, then there is a chance that it will be missed due to the decryptor not having responded in time.
  • a system for receiving a signal transmitted together with management messages comprising means for receiving the transmitted signal, signal processing means for processing the received signal, and a sub-system for controlling the signal processing means and acting in response to the management messages
  • the management messages include general messages and shared messages, a general message preceding and indicating that a plurality of shared messages are to be transmitted, and said sub-system requiring an appropriate shared message to enable processing of the signal and being arranged to monitor shared messages to detect a shared message which is addressed thereto, characterised in that the system includes means for recognising a general message, memory means are provided for storing a plurality of shared messages, means are provided for causing shared messages to be stored in said memory when a general message has been recognised and means are provided for enabling the sub-system to access the shared messages in the memory.
  • Such a system may be used as a conditional access system enabling a subscriber to obtain access to a signal when transmitted in scrambled form together with the said management messages.
  • the said signal processing means would be operable to process the scrambled signal under the control of a descrambler to enable the original signal to be recovered, and the sub-system would control the descrambler in response to the management messages.
  • the management messages may comprise general and shared entitlement management messages and the sub-system may require an appropriate shared entitlement management message to enable descrambling of the signal.
  • the sub-system may be operable to detect shared messages addressed thereto by reading a code carried by the general message, using that code to access one of a plurality of shared address (SA) values stored in a look-up table of the sub-system, and comparing the accessed SA value with respective shared address values carried by respective shared messages.
  • SA shared address
  • Such a look-up table may be held in a removable data storage device (such as a smartcard) with the sub-system including connection means operable to receive the data storage device and access information held therein.
  • FIG. 2 is a flow chart representing conventional handling of global and shared entitlement management messages (EMMs);
  • FIG 3 schematically illustrates a descrambler stage, as in Figure 1 , embodying the invention
  • Figure 4 schematically illustrates a decryptor stage for use with the descrambler of Figure 3.
  • Figure 5 is a flow chart illustrating the handling of EMMs in the descrambler and decryptor stages of Figures 3 and 4.
  • FIG. 1 A suitable reception system for such schemes is illustrated in Figure 1 and comprises a receiving dish 10 with associated satellite outdoor unit (SOU) 12, a receiver stage 14, a conditional access sub-system (CASS) 16, and a video monitor 18.
  • SOU satellite outdoor unit
  • SCS conditional access sub-system
  • the SOU 12 controls the dish in terms of, for example, satellite position, polarisation, band width selection of the down converter and so forth, in dependence on control signals received from a control stage 20 of the receiver 14.
  • the output from the SOU is an RF signal which is fed to a tuner stage 22 of the receiver 14.
  • the detailed construction of the SOU 12 will be familiar to those skilled in the art, plays no part in the operation of the present invention, and will not be further described.
  • the tuner 22 In response to user selection (via user I/O 24) of a particular encrypted 5 satellite broadcast channel, the tuner 22 outputs the scrambled AV signal to a data processing/descrambler stage 26.
  • Encrypted control words and entitlement management messages (EMMs) from the signal are passed to a decryptor stage 28 in the CASS 16.
  • a so-called "secure" part of the decryptor comprises a user-inserted smart card 30 accessed under control of a local 0 control unit 32 by a suitable card reader 34.
  • the decryptor 28 is able to decrypt the control words (as will be described), which decrypted codes are passed back to the descrambler 26 in the receiver.
  • These code words define how the scrambled AV signal is to be treated by the descrambler which then applies that treatment and outputs the descrambled 5 signal to the video monitor 18 for display.
  • the Eurocrypt system defines four types of EMMs, depending on whether the broadcast is for general reception or is to be limited to certain groups of subscribers. These are:
  • EMM-G Global
  • EMM-U Unique
  • EMM-S Shared Entitlement for a small group of users 4.
  • EMM-C Cold-C Entitlement for a large number of users All EMM packets have the same packet address; they differ only in terms of their packet type. However, EMM-U, EMM-C and EMM-S packets have an additional address field at the start of the packet, which is used to limit the applicability of the packet. For example, an EMM-U has a 36-bit Unique Address (UA) field which identifies the packet as belonging to one particular customer. The decryptor sends this UA information to the descrambler as part of an acquisition specification for the EMM-U packets.
  • UA Unique Address
  • the descrambler can then filter out all the EMM-U packets which do not contain the same UA value.
  • SA Shared Address
  • EMM-C packets which have a 12-bit Collective Address.
  • EMM-G and EMM-S messages which are used in conjunction to enable shared entitlements to be distributed.
  • a single EMM-G packet acts as a header for a series of EMM-S packets (each EMM-S for a different group of customers).
  • the SA given by the decryptor acquisition specification is determined by a Program Provider Identification (PPID) field given in the EMM- G.
  • PPID Program Provider Identification
  • a smartcard can contain details for up to 50 Program Providers, so the decryptor of the CASS 16 must analyse the EMM-G before requesting the EMM-S: it must identify the PPID in the packet in order to look up the correct SA for the descrambler 26 to use.
  • EMM-G processing begins at step 101 with receipt of an EMM-G.
  • the descrambler sends the EMM-G to the decryptor, where it is then analysed (step 103) to find out which EMM-S needs to be acquired.
  • the decryptor sends the acquisition specification to the descrambler (step 104) on receipt of which the descrambler starts acquisition of the desired EMM-S packets, at step 105.
  • the descrambler receives a first EMM-S and, at step 107, it passes this to the decryptor.
  • the application of the EMM-S by the decryptor will be described hereinafter.
  • the descrambler is set also to call for an EMM-S but without specifying any particular SA. As a result, it will receive all the EMM-S packets in the broadcast. However, it does not send them to the decryptor, but stores them in the hardware buffers of the acquisition system. Some little time later (having analysed the EMM-G), the decryptor will call for an EMM-S with a particular SA value. The descrambler then starts to sequentially read each successive EMM-S out of the buffer. It filters them based on the SA and passes those which match to the decryptor: the rest are thrown away.
  • FIGS 3 and 4 respectively show the descrambler and decryptor of Figure 1 in greater detail.
  • the incoming AV signal 40 includes a number of independent service components: in the example shown, the AV signal consists of a video signal V, two audio signals A 1 ⁇ A 2 - for example a soundtrack in two different languages, and two data signals D ⁇ D;, such as teletext.
  • a demultiplexer 42 receiving the incoming AV signal assigns the various components of the signal to respective ones of eight acquisition channels, each with buffering for eight packets of data.
  • the video, audio and data signal components V, A A 2 , D ⁇ D 2 are read out of respective buffers 44 to respective descrambling stages 52, 54, 56, 58, 60.
  • the encrypted code words (ECW) and entitlement management messages (EMM-G and EMM-S) from the incoming signal are assigned to further ones of the acquisition channels by the demultiplexer 42 and, after buffering in respective random access memories (RAMs 46,48,50), are passed via control logic/filter stage 38 to the decryptor 28, shown in Figure 4. Note that the card reader 34 and CASS local control 32 have been omitted from the figure for reasons of clarity.
  • the encrypted code words ECW may be buffered 62 in successive buffers and sequentially read out by multiplexer 64 for decrypting.
  • the EMM packets are read into a register 66: if the packet is an EMM-G, the PPID is read out to provide an address to the Provider memory 68 of the smartcard.
  • the Provider memory 68 in turn outputs a shared address acquisition specification (SAq) to the decoder.
  • SAq shared address acquisition specification
  • the packet is an EMM-S supplied in response to the SAq, this is supplied from the register 66 to a decryption stage 70 which also receives the encrypted code words ECW from the multiplexer 64, sequentially decrypts them on the basis of the EMM-S, and outputs the stream of decrypted code words DCW to the descrambler.
  • a decryption stage 70 which also receives the encrypted code words ECW from the multiplexer 64, sequentially decrypts them on the basis of the EMM-S, and outputs the stream of decrypted code words DCW to the descrambler.
  • different decrypted control words may be required for different ones of the AV signal components.
  • three control words CW.1-3 are shown, with CW.1 required for descrambling of both the video V and first audio A, components, CW.2 required for both the second audio A 2 and second data D 2 components, and CW.3 required for the first data component D v
  • CW.1 required for descrambling of both the video V and first audio A
  • CW.2 required for both the second audio A 2 and second data D 2 components
  • CW.3 required for the first data component D v
  • the process begins (at step 201) with the receipt of an EMM-G.
  • the descrambler requests all EMM-S packets (regardless of SA) and, under direction of the control stage 38, the EMM-S packets for each of the signal components are stored in the RAM buffer 50 of the assigned acquisition channel (step 203).
  • the descrambler sends the EMM-G to the decryptor register 66 via the RAM 48 in its acquisition channel and the control stage 38 (step 204).
  • the decryptor analyses the EMM-G (to find out which EMM-S packets to acquire) by reading the PPID field and using this to address Provider memory 68.
  • the decryptor sends the acquisition request SAq (output from memory 68) to the descrambler.
  • the control stage 60 of the descrambler reads the EMM-S values directly from the RAM buffer 50 and filters them by discarding all those whose SA does not correspond to that specified in the SAq. Finally, at step 208, the matched EMM-S packets are sent to the decryptor.
  • the problem of loss of early EMM-S packets is avoided as all are buffered once a global EMM-G has been received: the delay (G-S) between receipt of the EMM-G and following EMM-S packets is reduced as may be seen by comparing Figures 2 and 5.
  • the system also avoids the problems due to the EMM-G having a lower priority than, for example, code words since the descrambler will start to store the EMM-S packets as soon as the EMM-G is detected, even if priority levels delay the sending of the EMM-G to the decryptor. From reading the present disclosure, other modifications will be apparent to persons skilled in the art.

Landscapes

  • Engineering & Computer Science (AREA)
  • Signal Processing (AREA)
  • Computer Security & Cryptography (AREA)
  • Multimedia (AREA)
  • Computer Hardware Design (AREA)
  • Computing Systems (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Databases & Information Systems (AREA)
  • Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)

Abstract

La présente invention concerne un système de manipulation de paquets de données, destiné à recevoir une séquence de paquets de données dans laquelle le premier paquet (EMM-G) comprend un codage qui identifie un ou plusieurs des paquets suivants (EMM-S), suivant les besoins du système. Après la réception du premier paquet (201), tous les paquets suivants sont stockés dans une mémoire tampon (202, 203) pendant que le premier est analysé (204-206) pour déterminer lequel des paquets suivants est nécessaire, si c'est le cas. Cela étant fait, les paquets suivants sont extraits de la mémoire tampon (207) et ceux qui ne sont pas nécessaires sont supprimés. Le système trouve une application particulière dans le traitement des messages d'habilitation concernant les émissions de signaux audio/vidéo cryptés.
EP96917632A 1995-07-15 1996-07-03 Manipulation de paquets de donnees Withdrawn EP0793880A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
GBGB9514525.6A GB9514525D0 (en) 1995-07-15 1995-07-15 Data packet handling
GB9514525 1995-07-15
PCT/IB1996/000640 WO1997004553A1 (fr) 1995-07-15 1996-07-03 Manipulation de paquets de donnees

Publications (1)

Publication Number Publication Date
EP0793880A1 true EP0793880A1 (fr) 1997-09-10

Family

ID=10777748

Family Applications (1)

Application Number Title Priority Date Filing Date
EP96917632A Withdrawn EP0793880A1 (fr) 1995-07-15 1996-07-03 Manipulation de paquets de donnees

Country Status (4)

Country Link
EP (1) EP0793880A1 (fr)
JP (1) JPH10505995A (fr)
GB (1) GB9514525D0 (fr)
WO (1) WO1997004553A1 (fr)

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US6157719A (en) * 1995-04-03 2000-12-05 Scientific-Atlanta, Inc. Conditional access system
ID23380A (id) 1997-03-21 2000-04-20 Canal & Siciete Anonyme Metode dan aparatus untuk mencegah akses yang curang dalam sistem akses bersyarat
AU1581699A (en) * 1997-08-01 1999-03-08 Scientific-Atlanta, Inc. Conditional access system
KR100622964B1 (ko) * 1998-07-17 2006-09-12 톰슨 라이센싱 디지털 텔레비전 방송의 이벤트 액세스 관리 방법
IT1303242B1 (it) * 1998-08-11 2000-11-02 Cselt Ct Studi E Lab T Procedimento e sistema per l'erogazione controllata di servizinumerici quali, ad esempio, servizi telematici multimediali.
ES2270494T3 (es) 1998-09-01 2007-04-01 Irdeto Access B.V. Sistema de comunicacion de datos.
DE69834396T2 (de) 1998-09-01 2007-02-22 Irdeto Access B.V. Sicheres Datensignalübertragungssystem
JP4382178B2 (ja) 1998-09-11 2009-12-09 パナソニック株式会社 受信装置
FR2812781A1 (fr) 2000-08-04 2002-02-08 Thomson Multimedia Sa Methode de distribution securisee de donnees numeriques representatives d'un contenu multimedia
US8098820B2 (en) 2001-03-14 2012-01-17 Thomson Licensing Conditional access system for broadcast digital television
WO2005018654A1 (fr) * 2003-08-26 2005-03-03 Obschestvo S Ogranichennoi Otvetstvennostyu Alef-Farma Utilisation de souches de enterococcus faecium pour traiter l'insuffisance hepatique, pour regenerer et pour intensifier le metabolisme hepatique
US7776529B2 (en) 2003-12-05 2010-08-17 Life Technologies Corporation Methine-substituted cyanine dye compounds
JP5306811B2 (ja) 2005-05-11 2013-10-02 ライフ テクノロジーズ コーポレーション ２本鎖ｄｎａへの高い選択性を有する蛍光化学物質及びそれらの使用
WO2008094065A1 (fr) * 2007-02-02 2008-08-07 Alexei Nikolaevich Parfenov MÉTHODE ET AGENT À BASE DE SOUCHES D'Enterococcus faecium M (VKPM B-3490) ET D'Enterococcus faecium M-3185 (VKPM B-3491) SERVANT AU TRAITEMENT D'HÉPATITES VIRALES

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FR2694860B1 (fr) * 1992-08-13 1994-09-30 France Telecom Procédés de diffusion et de réception de programmes de télévision à accès conditionnel à temps de commutation de programmes réduit.
DE4321776C1 (de) * 1993-06-30 1994-12-08 Siemens Ag Verfahren zum Bilden und Analysieren von informationselementeorientierten Signalisierungsmeldungen in Kommunikationseinrichtungen

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Also Published As

Publication number Publication date
GB9514525D0 (en) 1995-09-13
WO1997004553A1 (fr) 1997-02-06
JPH10505995A (ja) 1998-06-09

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