1、 International Telecommunication Union ITU-T H.235.2TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2005) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Systems aspects H.323 security: Signature security profile ITU-T Recommendation H.235.2 ITU-T H-SERIES RECO
2、MMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS H.100H.199 INFRASTRUCTURE OF AUDIOVISUAL SERVICES General H.200H.219 Transmission multiplexing and synchronization H.220H.229 Systems aspects H.230H.239 Communication procedures H.240H.259 Coding of moving vid
3、eo H.260H.279 Related systems aspects H.280H.299 Systems and terminal equipment for audiovisual services H.300H.349 Directory services architecture for audiovisual and multimedia services H.350H.359 Quality of service architecture for audiovisual and multimedia services H.360H.369 Supplementary serv
4、ices for multimedia H.450H.499 MOBILITY AND COLLABORATION PROCEDURES Overview of Mobility and Collaboration, definitions, protocols and procedures H.500H.509 Mobility for H-Series multimedia systems and services H.510H.519 Mobile multimedia collaboration applications and services H.520H.529 Security
5、 for mobile multimedia systems and services H.530H.539 Security for mobile multimedia collaboration applications and services H.540H.549 Mobility interworking procedures H.550H.559Mobile multimedia collaboration inter-working procedures H.560H.569 BROADBAND AND TRIPLE-PLAY MULTIMEDIA SERVICES Broadb
6、and multimedia services over VDSL H.610H.619 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. H.235.2 (09/2005) i ITU-T Recommendation H.235.2 H.323 security: Signature security profile Summary This Recommendation describes an optional security profile for deploying
7、 digital signatures to secure the H.225.0 signalling. In earlier versions of the H.235 subseries, this profile was contained in Annex E/H.235. Appendices IV, V, VI to H.235.0 show the complete clause, figure, and table mapping between H.235 versions 3 and 4. Source ITU-T Recommendation H.235.2 was a
8、pproved on 13 September 2005 by ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. Keywords Authentication, certificate, digital signature, encryption, integrity, key management, multimedia security, security profile. ii ITU-T Rec. H.235.2 (09/2005) FOREWORD The Internati
9、onal Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. 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 issuing Recommendation
10、s 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 topics. The approval
11、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 expression “Administration“
12、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 applicability) and compliance with
13、 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 Recommendation is required
14、 of any party. INTELLECTUAL PROPERTY RIGHTS ITU 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 of claimed Intellectual
15、 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 not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. Howeve
16、r, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2006 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU
17、-T Rec. H.235.2 (09/2005) iii CONTENTS Page 1 Scope 1 2 References. 1 2.1 Normative references 1 2.2 Informative references 2 3 Terms and definitions . 2 4 Symbols and abbreviations. 3 5 Conventions 4 6 Overview 5 6.1 H.323 requirements 7 7 Digital signatures with public/private key pairs details (p
18、rocedure II) 8 8 Multipoint conferencing procedures. 9 9 End-to-end authentication (procedure III) 9 10 Authentication-only 11 11 Authentication and integrity . 12 12 Computation of the digital signature 12 13 Verification of the digital signature 13 14 Handling of certificates. 13 15 Usage illustra
19、tion for procedure II 15 15.1 RAS message authentication, integrity and non-repudiation . 15 15.2 RAS authentication only. 16 15.3 H.225.0 message authentication, integrity and non-repudiation 17 15.4 H.245 message authentication and integrity. 17 16 H.235 version 1 compatibility 18 17 Multicast beh
20、aviour 18 18 List of secure signalling messages 18 18.1 H.225.0 RAS 18 18.2 H.225.0 call signalling 19 19 Usage of sendersID and generalID. 19 20 List of object identifiers 20 ITU-T Rec. H.235.2 (09/2005) 1 ITU-T Recommendation H.235.2 H.323 security: Signature security profile 1 Scope This Recommen
21、dation describes an optional security profile for deploying digital signatures to secure the H.225.0 signalling. 2 References 2.1 Normative references The following ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Reco
22、mmendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other refer
23、ences listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T Recommendation H.225.0 (2003), Call signalling protocols and media
24、 stream packetization for packet-based multimedia communication systems. ITU-T Recommendation H.235 (1998), Security and encryption for H-series (H.323 and other H.245-based) multimedia terminals. ITU-T Recommendation H.235.0 (2005), H.323 security: Framework for security in H-series (H.323 and othe
25、r H.245-based) multimedia systems. ITU-T Recommendation H.235.1 (2005), H.323 security: Baseline security profile. ITU-T Recommendation H.235.6 (2005), H.323 security: Voice encryption profile with native H.235/H.245 key management. ITU-T Recommendation H.245 (2005), Control protocol for multimedia
26、communication. ITU-T Recommendation H.323 (2003), Packet-based multimedia communications systems. ITU-T Recommendation Q.931 (1998), ISDN user-network interface layer 3 specification for basic call control. ITU-T Recommendation X.509 (2005) | ISO/IEC 9594-8:2005, Information technology Open Systems
27、Interconnection The Directory: Public-key and attribute certificate frameworks. ITU-T Recommendation X.800 (1991), Security architecture for Open Systems Interconnection for CCITT applications. ITU-T Recommendation X.803 (1994) | ISO/IEC 10745:1995, Information technology Open Systems Interconnectio
28、n Upper layers security model. ITU-T Recommendation X.810 (1995) | ISO/IEC 10181-1:1996, Information technology Open Systems Interconnection Security frameworks for open systems: Overview. ITU-T Recommendation X.811 (1995) | ISO/IEC 10181-2:1996, Information technology Open Systems Interconnection S
29、ecurity frameworks for open systems: Authentication framework. 2 ITU-T Rec. H.235.2 (09/2005) ISO/IEC 9798-3:1998, Information technology Security techniques Entity authentication Part 3: Mechanisms using digital signature techniques. IETF RFC 3280 (2002), Internet X.509 Public Key Infrastructure Ce
30、rtificate and Certificate Revocation List (CRL) Profile. 2.2 Informative references ISO/IEC 14888-3 ISO/IEC 14888-3:1998, Information technology Security techniques Digital signatures with appendix Part 3: Certificate-based mechanisms. PKCS PKCS #1 v2.0: RSA Cryptography Standard; RSA Laboratories;
31、October 1, 1998; http:/ PKCS PKCS #7: Cryptographic Message Syntax Standard, An RSA Laboratories Technical Note, version 1.5, Revised November 1, 1993; http:/ RFC1321 IETF RFC 1321 (1992), The MD5 Message-Digest Algorithm. RFC3447 IETF RFC 3447 (2003), Public-Key Cryptography Standards (PKCS) #1: RS
32、A Cryptography Specifications Version 2.1. 3 Terms and definitions For the purposes of this Recommendation, the definitions given in clauses 3/H.323, 3/H.225.0 and 3/H.245 apply along with those in this clause. Some of the terms used in this Recommendation are also defined in ITU-T Recs X.800 | ISO
33、7498-2, X.803 | ISO/IEC 10745, X.810 | ISO/IEC 10181-1 and X.811 | ISO/IEC 10181-2. 3.1 certification authorities: Certification Authorities (CAs), when used in the context of electronic signature, certify public verification keys by issuing “Certificates“. 3.2 certificate repositories: Certificate
34、repositories (e.g., an X.500 Directory) hold user certificates and Certificate Revocation Lists (CRLs). They are trusted to make that information accessible but are not responsible for the content or accuracy of the information they receive from the CAs or the RAs. 3.3 digital signature: Is a crypto
35、graphic transformation (using an asymmetric cryptographic technique) of the numerical representation of a data message, such that any person having the signed message and the relevant public key can determine that: i) the transformation was created using the private key corresponding to the relevant
36、 public key; and ii) the signed message has not been altered since the cryptographic transformation. 3.4 on-line certificate status providers: The On-line Certificate Status Protocol (OCSP) enables applications to determine the revocation state of an identified certificate. OCSP may be used to satis
37、fy some of the operational requirements of providing revocation information in a more timely way than is possible with CRLs. On-line certificate status providers can be seen as an alternative to the use of off-line CRLs. 3.5 proxy: The proxy is an intermediate H.323 entity similar to a gatekeeper. T
38、he proxy may be a separate network node or may be collocated with the functionality of an H.323 entity such as of the gatekeeper. The proxy may perform security tasks such as signature and certificate verification and access control. 3.6 registration authorities: Registration authorities act as inte
39、rmediaries between users and CAs. They receive requests from users and transmit them to the CAs in an appropriate form. ITU-T Rec. H.235.2 (09/2005) 3 3.7 time stamping authorities: Time stamping authorities are mandatory for non-repudiation in case of key loss or key compromise. In practice, they p
40、rovide a counter-signature to anyone, including a reliable time, over a hash and a hash identifier. 3.8 trust service provider: An entity, which can be used by other entities as a trusted intermediary in a communication or verification process, or as a trusted information service provider. This Reco
41、mmendation uses the following terms for provisioning the security services. 3.9 authentication-only: This security service of the signature security profile supports user authentication where the user authenticates when correctly digitally signing some piece of data by the private key. Note that thi
42、s security service does not provide countermeasures against arbitrary cut and paste, message manipulation or tampering attacks. Authentication-only may be useful for security proxies that verify authenticity of the message (data origin authentication) when forwarding the message to another destinati
43、on (e.g., Gatekeeper). NOTE The forwarding usually changes certain parts of the message; thus end-to-end integrity cannot be realized. Nevertheless, authentication-only can be applied on a hop-by-hop basis as well. Procedure III specifies this security service for an end-to-end scenario while proced
44、ure II specifies this security service for the hop-by-hop case. 3.10 authentication and integrity: This is a combined security service that supports message integrity in conjunction with user authentication. The user authenticates when correctly digitally signing some piece of data by the private ke
45、y. In addition to that, the message is protected against tampering. Both security services are provided by the same security mechanism. Combined authentication and integrity is possible only on a hop-to-hop basis. Procedure II specifies this security service. NOTE When digital signatures are applied
46、, a non-repudiation security service may be supported; this depends also on the settings of the key usage bits of the signing key in the certificate (see also RFC 3280). 4 Symbols and abbreviations This Recommendation uses the following abbreviations: ARQ Admission Request ASN.1 Abstract Syntax Nota
47、tion One CA Certification Authority CRL Certificate Revocation List DH Diffie-Hellman DNS Domain Name Service EP Endpoint EPID Endpoint Identifier GK Gatekeeper GKID Gatekeeper Identifier GRQ Gatekeeper Request ICV Integrity Check Value IP Internet Protocol ITU International Telecommunication Union
48、4 ITU-T Rec. H.235.2 (09/2005) LDAP Light-weight Directory Access Protocol LRQ Location Request MCU Multipoint Control Unit MD5 Message Digest 5 NAT Network Address Translation OID Object Identifier OCSP Online Certificate Status Protocol PKCS Public-Key Crypto System RA Registration Authority RAS R
49、egistration, Admission and Status RSA Rivest, Shamir, Adleman RTP Real-Time Protocol SHA Secure Hash Algorithm URL Uniform Resource Locator 5 Conventions In this Recommendation the following conventions are used: “shall“ indicates a mandatory requirement. “should“ indicates a suggested but optional course of action. “may“ indicates an optional course of action rather than a recommendation that something ta
