CEA-796-A-2005 NRSS Copy Protection Systems《国家可恢复安全标准复制保护系统》.pdf

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1、 CEA Standard NRSS Copy Protection Systems CEA-796-A R-2012 October 2005 NOTICE Consumer Electronics Association (CEA) Standards, Bulletins and other technical publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitat

2、ing interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards, Bulletins and other technical publications shall not in any respect preclude any member or nonmember

3、of CEA from manufacturing or selling products not conforming to such Standards, Bulletins or other technical publications, nor shall the existence of such Standards, Bulletins and other technical publications preclude their voluntary use by those other than CEA members, whether the standard is to be

4、 used either domestically or internationally. Standards, Bulletins and other technical publications are adopted by CEA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, CEA does not assume any liability to any patent owner, nor does it assume any obli

5、gation whatever to parties adopting the Standard, Bulletin or other technical publication. Note: The users attention is called to the possibility that compliance with this standard may require use of an invention covered by patent rights. By publication of this standard, no position is taken with re

6、spect to the validity of this claim or of any patent rights in connection therewith. The patent holder has, however, filed a statement of willingness to grant a license under these rights on reasonable and nondiscriminatory terms and conditions to applicants desiring to obtain such a license. Detail

7、s may be obtained from the publisher. This document does not purport to address all safety problems associated with its use or all applicable regulatory requirements. It is the responsibility of the user of this document to establish appropriate safety and health practices and to determine the appli

8、cability of regulatory limitations before its use. This document is copyrighted by the Consumer Electronics Association (CEA) and may not be reproduced, in whole or part, without written permission. Federal copyright law prohibits unauthorized reproduction of this document by any means. Organization

9、s may obtain permission to reproduce a limited number of copies by entering into a license agreement. Requests to reproduce text, data, charts, figures or other material should be made to CEA. (Formulated under the cognizance of the CEA R4.8 DTV Interface Subcommittee.) Published by CONSUMER ELECTRO

10、NICS ASSOCIATION 2012 Technology Phone 800-854-7179; Fax 303-397-2740; Internet http:/; Email 3 Systems for Communicating Copy Protection Methods Implemented between Host and the CA Device The value of CP_system_ID (as used in CEA-679-C, Parts A and B) shall be the system number defined in Section

11、4. 3.1 NRSS Part A System Protocols Information concerning commands necessary to use CEA-796-A systems in conjunction with NRSS Part A devices may be found CEA-679-C, Part A, Section 20. 3.2 NRSS Part B System Protocols Information concerning commands necessary to use CEA-796-A systems in conjunctio

12、n with NRSS Part B devices may be found in CEA-679-C, Part B, Section 8.9. 4 Copy Protection Systems When any of the copy protection systems described in Section 4 is implemented, it shall be implemented as indicated in this section. 4.1 System 1Data Scrambling with Diffie-Hellman Based Keys System

13、1 is designed to protect data returning from an NRSS module for display to the consumer. Protection is based on three primary principles: a) Restricting the devices that may receive copy protected data. Intellectual property embedded within this copy protection method will require a license for manu

14、facture, sale, or use. Licensing terms are designed to prevent devices that facilitate copying unscrambled bitstreams. Devices capable of recording an unscrambled bitstream, capable of making an unscrambled bitstream available for recording, or capable of being readily modified to record/provide bit

15、streams will not be granted a license. b) Scrambling data and protecting the keys so that passive devices cannot record signals and decode a clear bitstream. Content data is protected with DES and keys are negotiated using Diffie-Hellman (DH) key exchange. While it is possible to passively eavesdrop

16、 and decode data from the information, it is prohibitively difficult for the value of the data being sent, which is already-purchased A/V content. c) Closely coupling the host and CA module devices so that active devices to record bitstreams are difficult to create. Real-time constraints and complex

17、ities make active (man-in-the-middle) devices complex to design and manufacture. CEA-796-A 2 4.1.1 Licensing Licensing shall be required.1 4.2 System 2-Cryptographic Copy Protection I 4.2.1 Introduction This section describes a mechanism for protecting the interface between the user renewable condit

18、ional access module (POD) and the STB. The mechanism is simple yet secure, and lays the foundation for incorporating evolutionary improvements in the security of STBs, PODs, and key management infrastructures. The mechanism incorporates the following design principles: Localization of vulnerability,

19、 so security is a property of the integrity of the two communicating device (i.e., no universal secrets that enable the pirate to leverage off of the compromise of a third device); cryptographic protection of data; IP protected functionality that enables the legal prosecution of circumvention device

20、s; and the fresh authorization of devices by means of the bi-directional communication inherent in cable systems. 4.2.2 Licensing Licensing shall be required.2 4.3 System 3-Cryptographic Copy Protection II Basics a) Each CE manufacturer generates its own secret-public key pair and has the public key

21、 certified by the licensing authority (LA). The CE public-key is stored in the “Manufacturer Certificate” in the device. The CE secret-key is used by the CE manufacturer to certify its own individual devices public keys. It is proposed that the certificates be signed and checked using the Fiat Shami

22、r Signature algorithm (FSS). b) For each CE device, a DH secret-public key pair (x,gx mod p) is generated (perhaps by the device itself). The device DH public key (gx mod p) is certified by the CE device manufacturer. The device DH public key is stored in the “Device-Certificate” c) When two CE devi

23、ces-the host and the CA module-are connected, they exchange certificates that will enable them to perform an authenticated key exchange and establish a secure channel between them. d) After the certificates are verified, the devices have each others certified DH public key. Using that key, each devi

24、ce continues with the standard DH protocol (compute g(x1*x2) mod p, from the received public key and its own secret). This generates a shared key for these two devices. e) To generate a session key, the devices exchange some numbers which are hashed with the shared key above. The session key can be

25、updated as desired by the same hash mechanism-exchange of numbers and the hash. f) The session key is used to establish a control content channel on which control words and other items can be passed between the Host and CA module. 4.3.1 Licensing Licensing shall be required.3 4.4 System 4Cryptograph

26、ic Copy Protection III 4.4.1 Intellectual Property Implementation of the technology described in this section requires a license from the licensing authority and possibly other licenses. 1 For System 1 licensing information, contact: Manager, Licensing-Paris, Thomson multimedia, 46 quai Alphonse Le

27、Gallo, 92648 Boulogne Cedex, France, phone 330 1 41 86 5288, fax 330 1 41 86 0925, Email . 2 For System 2 licensing information, contact: CableLabs, 858 Coal Creek Circle , Louisville, CO 80027-9750, phone 303 661 9100. 3 For System 3 licensing information, contact: CTO, NDS-TI, Box 23012, Jerusalem

28、, Israel, phone 972-2-5894444, Fax 972-2-589-4000, Email or . CEA-796-A 3 4.4.2 Introduction This extension adapts the licensed technology to address the specific problem of copy protecting the clear stream as it leaves NRSS CA Modules to go to the host device for display and/or distribution to oth

29、er devices. This technology is designed to meet several goals: a) To be implementable at low complexity and in an acceptable timeframe. b) To support management of service, including response to theft of service, by the cable operator. c) To support open competition in retail products, whether singl

30、e- or multi-function. d) To support content owner (MPAA) and cable operator requirements for licensing enforcement of content protection requirements in hosts, including revocation of known compromised devices. e) To work across all types of networks: Cable, Terrestrial, and DBS. A back-channel is n

31、ot guaranteed, consequently the Copy Protection system must work with one-way only channels. 4.4.3 CA Interface Content Protection Architecture 4.4.3.1 Copy Protection Layers The content protection system addresses four fundamental layers of copy protection: a) Authentication and key exchange b) Con

32、tent encryption c) Copy control information d) System renewability For the NRSS CA Interface copy protection, there is an added layer of copy protection: e) CA enforcement 4.4.4 Licensing Licensing shall be required.4 4.5 System 5Open Copy Protection System 4.5.1 Introduction The intent of System 5

33、is to present an open system where all components are drawn from commonly available standards. It is asserted that System 5 methods are interface independent. System 5 specifies a protocol that protects copyrighted material traveling between a removable security element and a consumer electronics (C

34、E) device. In this section, a source is defined as a removable security element, and a sink is defined as the CE device. 4.5.2 Licensing Licensing shall be required.5 4 For System 4 licensing information, contact: Digital Transmission Licensing Administrator, Acting DTLA President, JF2-53, c/o Intel

35、 Corporation, 2111 NE 25th Avenue, Hillsboro, OR 97124, phone 503 264 8426, fax 503 264 9027, email dtla-, web http:/ . 5 For System 5 licensing information, contact: Intellectual Property Counsel, Philips, 345 Scarborough Road, Briarcliffe Manor, NY 10510-2099, phone 414 333 9665. CEA-796-A 4 (This

36、 page intentionally left blank.) CEA Document Improvement Proposal If in the review or use of this document a potential change is made evident for safety, health or technical reasons, please email your reason/rationale for the recommended change to standardsce.org. Consumer Electronics Association Technology & Standards Department 1919 S Eads Street, Arlington, VA 22202 FAX: (703) 907-7693 standardsce.org