1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T J.1003 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2014) SERIES J: CABLE NETWORKS AND TRANSMISSION OF TELEVISION, SOUND PROGRAMME AND OTHER MULTIMEDIA SIGNALS Conditional access and protection Renewable conditional
2、access system Specifications of network protocol for renewable conditional access system Recommendation ITU-T J.1003 Rec. ITU-T J.1003 (10/2014) i Recommendation ITU-T J.1003 Specifications of network protocol for renewable conditional access system Summary Recommendation ITU-T J.1003 specifies the
3、renewable conditional access system (RCAS) network protocol that supports authentication and secure download of conditional access client software (CACS) required in Recommendation ITU-T J.1001. History Edition Recommendation Approval Study Group Unique ID* 1.0 ITU-T J.1003 2014-10-29 9 11.1002/1000
4、/12323 _ * To access the Recommendation, type the URL http:/handle.itu.int/ in the address field of your web browser, followed by the Recommendations unique ID. For example, http:/handle.itu.int/11.1002/1000/11830-en. ii Rec. ITU-T J.1003 (10/2014) FOREWORD The International Telecommunication Union
5、(ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and
6、issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these
7、 topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expres
8、sion “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperability or applicabil
9、ity) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Re
10、commendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability
11、of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Rec
12、ommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2015 All rights reserved. No part of this publication may be reproduced, by any means whatsoeve
13、r, without the prior written permission of ITU. Rec. ITU-T J.1003 (10/2014) iii Table of Contents Page 1 Scope . 1 2 References . 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 3 6 Overview of RCAS network pro
14、tocol 4 7 Protocol processing procedures 5 7.1 Announcement phase 5 7.2 Key establishment phase 6 7.3 CAM registration phase 8 7.4 CACS renewal phase 9 8 Protocol security . 9 8.1 Message security 9 8.2 CAM client image security . 10 8.3 Security parameters generation 10 9 Message 11 9.1 Message for
15、mat 11 9.2 Message fields 13 9.3 Message notations 13 Annex A ASN.1 message notation between CASS and CAM . 14 Annex B Fast mode of network protocol for RCAS . 18 B.1 Protocol processing procedures 18 Annex C CAM cloning detection process . 22 Bibliography. 26 Rec. ITU-T J.1003 (10/2014) 1 Recommend
16、ation ITU-T J.1003 Specifications of network protocol for renewable conditional access system 1 Scope This Recommendation specifies the renewable conditional access system (RCAS) network protocol that supports authentication and secure download of conditional access client software (CACS) required i
17、n ITU-T J.1001. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are su
18、bject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a documen
19、t within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T J.1001 Recommendation ITU-T J.1001 (2012), Requirements for renewable conditional access system. ITU-T J.1002 Recommendation ITU-T J.1002 (2013), Pairing protocol specification for renewab
20、le conditional access system. ITU-T X.509 Recommendation ITU-T X.509 (2008) | ISO/IEC 9594-8:2008, Information technology Open systems interconnection The Directory: Public-key and attribute certificate frameworks. ITU-T X.690 Recommendation ITU-T X.690 (2008) | ISO/IEC 8825-1:2008, Information tech
21、nology ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER). 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 conditional access (CA) b-ITU-T J.193: The
22、conditional granting of access to cable services and content based upon what service suite has been purchased by the customer. 3.1.2 descrambling b-ITU-T J.93: The processes of reversing the scrambling function (see “scrambling“) to yield usable pictures, sound and data services. 3.1.3 entitlement c
23、ontrol messages (ECMs) b-ITU-T J.290: An ECM is an encrypted message that contains access criteria to various service tiers and a control word (CW). 3.1.4 entitlement management messages (EMMs) b-ITU-T J.290: The EMM contains the actual authorization data and shall be sent in a secure method to each
24、 CPE device. 3.1.5 scrambling b-ITU-T J.93: The process of using an encryption function to render television and data signals unusable to unauthorized parties. 2 Rec. ITU-T J.1003 (10/2014) 3.2 Terms defined in this Recommendation This Recommendation defines the following terms: 3.2.1 Security symbo
25、ls Security symbols Descriptions Pub(X) Public key of X Prv(X) Private key of X E(k,m) Encryption of a message m with key k. S(k,m) Digital signature for a message m with signing key k. H(m) SHA-256 hashing for a message m HMAC(k,m) HMAC-SHA1 for a message m with key k X|Y Concatenation of X and Y C
26、ert(X) X.509 certificate of X PRF(X) Pseudo random function having a seed value of X X msb(Y) Y bits from MSB of X 3.2.2 Parameter definitions Parameter names Descriptions DSC_ID The value of identification of DSC having a size of 40 bytes CAM_ID The value of identification of CAM having a size of 8
27、 bytes KeyPairingID The value of concatenation with CAM_ID and DSC_ID, i.e., CAM_ID|DSC_ID CWEK The abbreviation of control words encryption key and used to encrypt control words. The CWEK generation method is CWEK = H(CWEK|CAM_ID|DSC_ID)msb(128) KPK The abbreviation of key pairing key. The authoriz
28、ation centre (AC) generates the KPK if the KeyPairingID is valid. HMAC_KEY A hash-based message authentication code (HMAC) secret key. CAM uses HMAC_KEY to generate an HMAC value for the message including control words. The HMAC_KEY generation method is HMAC_KEY = H(RANDHMAC|CAM_ID|DSC_ID)msb(160),
29、Here RANDHMAC is achieved by PRF(X)msb(320) RAND Random number with 320 bits Ki The pre-shared key having the size of 128 bits. The AC uniquely assigns three Ki to each CAM. Ki should be a generated random generation function. 4 Abbreviations and acronyms This Recommendation uses the following Abbre
30、viations and acronyms: AC Authorization Centre ASN Abstract Syntax Notation BER Basic Encoding Rules CACS Conditional Access Client Software Rec. ITU-T J.1003 (10/2014) 3 CAM Conditional Access Module CASS CAM Authentication Sub-System CCCIEK Common CAM Client Image Encryption Key CCI CAM Client Ima
31、ge CHK Common Hash Key CPE Customer Premise Equipment CWEK Control Words Encryption Key DOCSIS Data Over Cable Service Interface Specification HMAC Hash-based Message Authentication Code ICCIEK Individual CAM Client Image Encryption Key IHK Individual Hash Key IV Initialization Vector KPK Key Pairin
32、g Key MEK Message Encryption Key MK Master Key PRF Pseudo Random number generation Function PRNG Pseudo Random Number Generator RCAS Renewable Conditional Access System 5 Conventions In this Recommendation: The keywords “is required to“ indicate a requirement which must be strictly followed and from
33、 which no deviation is permitted if conformance to this document is to be claimed. The keywords “is recommended“ indicate a requirement which is recommended but which is not absolutely required. Thus this requirement need not be present to claim conformance. The keywords “is prohibited from“ indicat
34、e a requirement which must be strictly followed and from which no deviation is permitted if conformance to this document is to be claimed. The keywords “can optionally“ indicate an optional requirement which is permissible, without implying any sense of being recommended. This term is not intended t
35、o imply that the vendors implementation must provide the option and the feature can be optionally enabled by the network operator/service provider. Rather, it means the vendor may optionally provide the feature and still claim conformance with the specification. In the body of this document and its
36、annexes, the words shall, shall not, should, and may sometimes appear, in which case they are to be interpreted, respectively, as is required to, is prohibited from, is recommended, and can optionally. The appearance of such phrases or keywords in an appendix or in material explicitly marked as info
37、rmative are to be interpreted as having no normative intent. 4 Rec. ITU-T J.1003 (10/2014) 6 Overview of RCAS network protocol Figure 1 Reference architecture of RCAS Figure 1 is a reference architecture illustrating a configuration of a renewable conditional access system (RCAS). The RCAS provides
38、a mutual authentication method between a conditional access module (CAM) and a CAM authentication sub-system (CASS). A mutual authentication includes the CAM of a RCAS set-top box, the CASS of a RCAS headend and an authorization centre (AC) connected to the CASS. As shown in Figure 1 the CAM and the
39、 CASS interactively communicate with each other through a cable network for this mutual authentication. The AC provides a variety of important information used for authentication through the CASS. The CASS transmits information used for authentication received from the AC to the CAM by means of a su
40、itable communication system such as data over cable service interface specification (DOCSIS). All types of key information generated during the authentication are managed by the AC. When the authentication is completed normally, the conditional access client software (CACS) is transmitted to the CAM
41、 through a secure CACS download sub-system. After downloading the CACS, the CAM obtains viewing entitlement with respect to a scrambled and transmitted broadcasting signal and provides a subscriber with a fee-based broadcasting service through customer premise equipment (CPE). The messages exchanged
42、 among the CAM, the CASS and the AC are defined as a RCAS network protocol. The RCAS network protocol enables a security and authentication function for messages exchanged among the CAM, the CASS and the AC. The specification of RCAS network protocol includes the following functions for authenticati
43、on and secure download of CACS that are specified in ITU-T J.1001: Security announcement function: The ability to provide information such as initial configuration, upgrade, or access information, to CAMs in the network through the RCAS network protocol. Key establishment and authentication function
44、: The establishment CACS encryption and authentication key which is used for encrypting CACS to protect the image of CACS while it is delivered from the headend to CAM. Supporting RCAS pairing function: It is required that RCAS network protocol supports the RCAS pairing function which is specified i
45、n ITU-T J.1002 while RCAS network protocol is operated. Renewal information announcement function: The ability to provide the CACS download information to CAM through the RCAS network protocol. Rec. ITU-T J.1003 (10/2014) 5 7 Protocol processing procedures Figure 2 is a sequence chart illustrating a
46、 mutual authentication method based on RCAS network protocol. In this protocol, it is assumed that the CAM retains an AC certificate (AC X.509 certificate), a CAM certificate, a Ki value and a three operator variant algorithm configuration field (OP). The CASS is assumed to retain an AC certificate
47、(AC X.509 certificate) and a CASS certificate (CASS X.509 certificate). The AC is assumed to retain an AC certificate (AC X.509 certificate), a CASS certificate (CASS X.509 certificate), a CAM certificate, a three OP, a Ki value and a key pairing identifier (ID). Under these assumptions, the sequenc
48、e chart of a mutual authentication method includes an Announcement phase, a Key establishment phase, a CAM registration phase and a CACS renewal phase as shown in the Figure 2. Figure 2 A sequence chart of RCAS network protocol 7.1 Announcement phase In the announcement phase, the RCAS headend contr
49、ols the CASS to transmit an RCASAnnounce message or an RCASRenewal message to the CAM. The role of this message is to notify the start of RCAS network protocol as well as to provide the CASS server access information to all CAMs. The RCASAnnounce message provides the CAM Client Version information such as CAM HW version, CAM SW version and CACS type, etc., as well as CASS information such as the IP address of CASS, IP connection type (e.g., TCP or UDP) and the Listening
