1、ETSI ETR*:289 9b m 3400855 0339649 967 m - REPORT ETR 289 October 1996 Source: EBU/CNELEC/ETSI-JTC Reference: DT WJTC-DVB-14 ICs: 33.020 Key words: Digital, video, broadcasting, DVB, TV, CA, security J. European Broadcasting Union Auq Union Europenne de Radio-Tlvision %JR Digital Video Broadcasting
2、(DVB); Support for use of scrambling and Conditional Access (CA) wit hin digital broadcasting systems ETSI European Telecommunications Standards Institute ETSI Secretariat Postal address: F-O6921 Sophia Antipolis CEDEX - FRANCE Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - F
3、RANCE X.400: c=fr, a=atlas, p=etsi, s=secretariat - Internet: secretariatQetsi.fr Tel.: +33 4 92 94 42 O0 - Fax: +33 4 93 65 47 16 Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the foregoing restriction extend to reproduction in all m
4、edia. O European Telecommunications Standards Institute 1996. O European Broadcasting Union 1996. All rights reserved. - ETSI ETR*289 96 3400855 0339650 b89 Page 2 ETR 289: October 1996 . Whilst every care has been taken in the preparation and publication of this document, errors in content, typogra
5、phical or otherwise, may occur. If you have comments concerning its accuracy, please write to ETSI Editing and Committee Support Dept.“ at the address shown on the title page. . ETSI ETR*287 96 3400855 0137651 515 Contents Page 3 ETR 289: October 1996 Foreword . 5 Introduction 5 Scope 7 References 7
6、 Definition and abbreviations 8 3.1 Definition 8 3.2 Abbreviations . 8 The DVB Scrambling Algorithm 9 4.1 The DVB Scrambling Algorithm custodian . 10 Use of the scrambling algorithm in an MPEG-2 environment . 10 5.1 Scrambling control field . 10 5.2 Registration of CA System ID 10 5.3 PES level scra
7、mbling issues 11 Trans-control issues when crossing distribution media boundaries 11 Conditional Access (CA) data . 11 History 13 ETSI ETRx289 7b 3400855 0137652 451 = Page 4 ETR 289: October 1996 Blank page 8 ETSI ETR*E89 96 3400855 0339653 398 Page 5 ETR 289: October 1996 Foreword This ETSI Techni
8、cal Report (ETR) has been produced under the authority of the Joint Technical Committee (JTC) of the European Broadcasting Union (EBU), Comit Europen de Normalisation ELECtrotechnique (CENELEC) and the European Telecommunications Standards Institute (ETSI). This ETR may be converted into an ETS afte
9、r market feedback. For this purpose, the wording of an ETS rather than of an ETR is used. ETRs are informative documents resulting from ETSI studies which are not appropriate for European Telecommunication Standard (ETS) or Interim European Telecommunication Standard (LETS) status. An ETR may be use
10、d to publish material which is either of an informative nature, relating to the use or the application of ETSs or I-ETSc, or which is immature and not yet suitable for formal adoption as an ETC or an LETS. NOTE: The EBU/ETSI JTC was established in 1990 to co-ordinate the drafting of ETSs in the spec
11、ific field of broadcasting and related fields. Since 1995 the JTC became a tripartite body by including in the Memorandum of Understanding also CENELEC, which is responsible for the standardization of radio and television receivers. The EBU is a professional association of broadcasting organisations
12、 whose work includes the co-ordination of its Members activities in the technical, legal, programme-making and programme-exchange domains. The EBU has Active Members in about 60 countries in the European Broadcasting Area; its headquarters is in Geneva *. * European Broadcasting Union Case Postale 6
13、7 CH-1218 GRAND SACONNEX (Geneva) Switzerland Tel: +41 22 717 21 11 Fax: +41 22 717 24 81 Introduction This ETR addresses the addition of Conditional Access (CA) elements to the ISO/IEC 13818-1 (MPEG-2) l. The Conditional Access System (CAS) is a very sensitive area, and this ETR describes the minim
14、um set of common CA elements necessary to achieve interoperability between different CA Systems. It is reasonable to expect these common CA elements to be incorporated in every piece of consumer receiver equipment for digital TV. In additional clauses, some CA elements are defined which are not need
15、ed from an interoperability point of view, but will enhance commonality in cable TV (CATV) receiver eq ui pmen t. - ETSI ETR*Z b = 3400855 0139654 224 Page 6 ETR 289: October 1996 Blank page Page 7 ETR 289: October 1996 ETSI ETRn289 96 3400855 0339655 3bO 1 scope This ETSI Technical Report (ETR) spe
16、cifies the common DVB Conditional Access elements. It was developed principally to provide support for a wide range of Conditional Access Systems (CASs) which are based on ISO/IEC 13818-1 (MPEG-2) l and the DVB specifications. The ETR specifies those aspects which are required for co-existence of mu
17、ltiple Conditional Access Systems in a single data stream. 2 References For the purposes of this ETR, the following references apply: 31 t41 ISO/IEC 13818-1 : “Information Technology - Generic coding of moving pictures and associated audio: Systems, Recommendation H.222.0“. ISO/IEC 1381 8-4: “Inform
18、ation Technology - Generic coding of moving pictures and associated audio: Compliance“. ETR 162: “Digital broadcasting systems for television, sound and data services; Allocation of Service Information (Si) codes for Digital Video Broadcasting (DVB) systems“. ETS 300 468: “Digital Video Broadcasting
19、 (DVB); Specification for Service Information (SI) in DVB systems“. ETR 21 1 : Digital broadcasting systems for television; Guidelines on the implementation and usage of Sewice Information (Si)“. ETR 154: “Digital Video Broadcasting (DVB); Implementation guidelines for the use of MPEGQ Systems, Vide
20、o and Audio in satellite, cable and terrestrial broadcasting applications“. Page 8 ETSI ETR*Z89 b 3400855 0139656 OT ETR 289: October 1996 3 Definition and abbreviations 3.1 Definition For the purposes of this ETR, the following definition applies: Custodian: Distribution authority for the DVB Scram
21、bling Algorithm. 3.2 Abbreviations For the purposes of this ETR, the following abbreviations apply: AF bslbf CA CAS CATV DVB ECM EMM ID I EC IS0 MPEG NDA PES PID PMT PSI SMS TS uimsbf Adaptation Field bit string, let bit first Conditional Access Conditional Access System Community Access Television
22、Digital Video Broadcasting Entitlement Control Message Entitlement Management Messages Identifier International Electrotechnical Commission International Organization for Standardization Moving Picture Experts Group Non-Disclosure Agreement Packetized Elementary Stream Packet Identifier Program Map
23、Table Program Specific Information Subscriber Management System Transport Stream unsigned integer, most significant bit first Page 9 ETR 289: October 1996 ETSI ETR*289 96 W 3400855 0339657 T33 Y 4 The DVB Scrambling Algorithm The Scrambling Algorithm specified for common DVB applications has been de
24、signed to minimise the likelihood of piracy attack over a long period of time and thus contains highly security sensitive information. The technical details of the scrambling algorithm can only be made available to bona-fide users upon signature of a Non-Disclosure Agreement (NDA) administered by a
25、Custodian. This clause contains a summary of the scrambling method and some of the implementation issues. The scrambling algorithm operates on the payload of a Transport Stream (TS) packet in the case of TS-level scrambling. A structuring of PES packets is used to implement PES-level scrambling with
26、 the same scrambling algorithm. The PES level scrambling method requires that the PES packet header shall not be scrambled (as required in ISO/IEC 13818-1 l) and TS packets containing parts of a scrambled PES packet shall not contain an Adaptation Field (with the exception of the TS packet containin
27、g the end of the PES packet). The header of a scrambled PES packet shall not span multiple TS packets. The TS packet carrying the start of a scrambled PES packet is filled by the PES header and the first part of the PES packet payload. In this way, the first part of the PES packet payload is scrambl
28、ed exactly as a TS packet with a similar size payload. The remaining part of the PES packet payload is split in super-blocks of 184 bytes. Each super- block is scrambled exactly as a TS packet payload of 184 bytes. The end of the PES packet payload is aligned with the end of the TS packet (as requir
29、ed in ISOAEC 13818-1 l) by inserting an Adaptation Field of suitable size. If the length of the PES packet is not a multiple of 184 bytes, the last part of the PES packet payload (from 1 to 183 bytes) is scrambled exactly as a TS packet with a similar size payload. A schematic diagram describing the
30、 mapping of scrambled PES packets into TS packets is given in figure 1. I PES header 1 PES data (scrambled) I TS packets Figure 1: PES level scrambling diagram The PES level scrambling method puts some constraints on the multiplexing process in order to make the de-scrambling process easier. Subclau
31、se 5.3 gives recommendations for the mapping of scrambled PES packets into TS packets. This method may create some bit-rate overhead if Adaptation Fields (AFs) are needed in TS packets carrying scrambled PES packets. In that case a TS packet containing only an Adaptation Field needs to be inserted.
32、For applications that scramble MPEG-2 Sections, a problem occurs as the MPEG-2 specified syntax does not include any scrambling control bits. Therefore, the scrambling of Sections shall be at the TS level and shall be signalled by the scrambling control field bits. Clear and scrambled Sections canno
33、t be combined in a single TS packet. The MPEG-2 defined padding mechanism can be used to create TS packets with only clear or only scrambled Sections. This means that the end of a TS packet carrying a Section shall be filled with bytes having a value of OxFF, in order to separate clear and scrambled
34、 Sections into different TS packets. The algorithm is designed to minimise the amount of memory in the de-scrambler circuit at the expense of the complexity in the scrambler. The exact amount of memory and the de-scrambling delay depend on actual implementations. Page10 ETSI ETR*28S 96 D 3400855 013
35、7658 77T ETR 289: October 1996 Bit values O0 o1 10 11 4.1 The DVB Scrambling Algorithm custodian Description No scrambling of TS packet payload (MPEG-2 compliant) Reserved for future DVB use TS packet scrambled with Even Key TS packet scrambled with Odd Key The Scrambling Algorithm for DVB applicati
36、ons is made available by the Custodian upon signature of a Non-Disclosure Agreement and provided potential users are bone fide. The Custodian is ETSI itself and for information can be obtained by contacting: Bit values O0 o1 10 11 European Telecommunications Standards Institute (ETSI) Administration
37、 Department F-O6921 Sophia Antipolis Cedex FRANCE Tel.: +33 4 92 94 42 O0 Fax: +33 4 93 65 47 16 Description No scrambling of PES packet payload (MPEGB compliant) Reserved for future DVB use PES packet scrambled with Even Key PES packet scrambled with Odd Key 5 Use of the scrambling algorithm in an
38、MPEG-2 environment This clause contains syntactical definitions and some operational recommendations for MPEG-2 bitstreams allowing efficient use of the common scrambling algorithm. 5.1 Scrambling control field The MPEG-2 Systems specification contains a scrambling control field of two bits, both in
39、 the TS packet header and in the PES packet header. The meaning of these two bits is only partially defined in MPEGB , as only one value is defined. Table 1 gives a full definition of the scrambling control bits in the TS packet header. 5.2 Registration of CA System ID Some registration needs to tak
40、e place on the CA-System-ID field in the MPEGP CA-descriptor0 to indicate the various CA Systems Specifiers. The CA-System-ID field allows easy filtering of relevant CA information for a particular Digital TV receiver. ETR 162 3 specifies a range of 256 values ( kN; i+) I CA-data-byte Semantics for
41、the CMT: No. of bits Identifier 8 uimsbf 1 bslbf 1 bslbf 2 bslbf 12 uimsbf 8 bslbf table-id: See table 4. table-id value ox00 - 0x02 Ox03 - 03F Ox40 - Ox72 Ox73 - 07F 0x80 Table 4: Allocation of table identifiers Description MPEG specified MPEG-reserved V2-SI specified DVB-resewed CA-message-section
42、, ECM 0x8 1 Ox82 - 08F Ox90 - OXFE CA-message-section, ECM CA-message-section, CA System private Drivate IOFF I ISO-resewed section-syntax-indicator: This is a 1 -bit indicator which shall always be set to “O“. DVB-reserved: This term indicates that the field may be used in the future for DVB applic
43、ations and therefore shall not be used for private applications. ISO-reserved: The term “ISO-resewed“ indicates that the value may be used in the future for IS0 defined extensions and therefore is not be specified by DVB. CA-section-length: A 12-bit field. It specifies the number of bytes that follo
44、w the section-length field up to the end of the section. CA-data-byte: This is an 8-bit field which carries private CA information. Up to the first 17 CA-data-bytes may be used for address filtering. A range of 16 table-id values is available for CA-message-sections carrying different types of Condi
45、tional Access information. Two values of the table-id field (0x80 and 0x81) are reserved for transmission of ECM data, A change of these two table-id values signals that a change of ECM contents has occurred. This change condition can be used for filtering of Conditional Access information. ETSI ETR*E! 96 3400855 0339bb1i 464 = October 1996 Page 13 ETR 289: October 1996 _ First Edition History Document history c ISBN 2-7437-1032-2 Dpt lgal : Octobre 1996
