1、 Reference number ISO/IEC 8825-7:2015(E) ISO/IEC 2015INTERNATIONAL STANDARD ISO/IEC 8825-7 Second edition 2015-11-15 Information technology ASN.1 encoding rules: Specification of Octet Encoding Rules (OER) Technologies de linformation - Rgles de codage ASN.1: Spcification des rgles de codage des oct
2、ets (OER) ISO/IEC 8825-7:2015(E) COPYRIGHT PROTECTED DOCUMENT ISO/IEC 2015 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or
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4、o.org Published in Switzerland ii ISO/IEC 2015 All rights reservedISO/IEC 8825-7:2015(E) ISO/IEC 2015 All rights reserved iiiForeword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardiza
5、tion. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutua
6、l interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordanc
7、e with the rules given in the ISO/IEC Directives, Part 2. The main task of the joint technical committee is to prepare International Standards. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standar
8、d requires approval by at least 75 % of the national bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. This second editi
9、on cancels and replaces the first edition of ISO/IEC 8825-7:2014 which has been technically revised. ISO/IEC 8825-7 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 6, Telecommunications and information exchange between systems, in collaboration with I
10、TU-T. The identical text is published as ITU-T X.696 (08/2015). International Telecommunication Union ITU-T X.696 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (08/2015) SERIES X: DATA NETWORKS, OPEN SYSTEM COMMUNICATIONS AND SECURITY OSI networking and system aspects Abstract Syntax Notation One
11、(ASN.1) Information technology ASN.1 encoding rules: Specification of Octet Encoding Rules (OER) Recommendation ITU-T X.696 ITU-T X-SERIES RECOMMENDATIONS DATA NETWORKS, OPEN SYSTEM COMMUNICATIONS AND SECURITY PUBLIC DATA NETWORKS Services and facilities X.1X.19 Interfaces X.20X.49 Transmission, sig
12、nalling and switching X.50X.89 Network aspects X.90X.149 Maintenance X.150X.179 Administrative arrangements X.180X.199 OPEN SYSTEMS INTERCONNECTION Model and notation X.200X.209 Service definitions X.210X.219 Connection-mode protocol specifications X.220X.229 Connectionless-mode protocol specificati
13、ons X.230X.239 PICS proformas X.240X.259 Protocol Identification X.260X.269 Security Protocols X.270X.279 Layer Managed Objects X.280X.289 Conformance testing X.290X.299 INTERWORKING BETWEEN NETWORKS General X.300X.349 Satellite data transmission systems X.350X.369 IP-based networks X.370X.379 MESSA
14、GE HANDLING SYSTEMS X.400X.499 DIRECTORY X.500X.599 OSI NETWORKING AND SYSTEM ASPECTS Networking X.600X.629 Efficiency X.630X.639 Quality of service X.640X.649 Naming, Addressing and Registration X.650X.679 Abstract Syntax Notation One (ASN.1) X.680X.699 OSI MANAGEMENT Systems management framework a
15、nd architecture X.700X.709 Management communication service and protocol X.710X.719 Structure of management information X.720X.729 Management functions and ODMA functions X.730X.799 SECURITY X.800X.849 OSI APPLICATIONS Commitment, concurrency and recovery X.850X.859 Transaction processing X.860X.879
16、 Remote operations X.880X.889 Generic applications of ASN.1 X.890X.899 OPEN DISTRIBUTED PROCESSING X.900X.999 INFORMATION AND NETWORK SECURITY X.1000X.1099 SECURE APPLICATIONS AND SERVICES X.1100X.1199 CYBERSPACE SECURITY X.1200X.1299 SECURE APPLICATIONS AND SERVICES X.1300X.1399 CYBERSECURITY INFOR
17、MATION EXCHANGE X.1500X.1599 CLOUD COMPUTING SECURITY X.1600X.1699 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T X.696 (08/2015) i INTERNATIONAL STANDARD ISO/IEC 8825-7 RECOMMENDATION ITU-T X.696 Information technology ASN.1 encoding rules: Specification of Octet
18、 Encoding Rules (OER) Summary Recommendation ITU-T X.696 | ISO/IEC 8825-7 specifies two sets of binary encoding rules that can be applied to values of all ASN.1 types using less processing resources than the Basic Encoding Rules and its derivatives (described in Rec. ITU-T X.690 | ISO/IEC 8825-1) an
19、d the Packed Encoding Rules (described in Rec. ITU-T X.691 | ISO/IEC 8825-2). History Edition Recommendation Approval Study Group Unique ID *1.0 ITU-T X.696 2014-08-29 17 11.1002/1000/12151 2.0 ITU-T X.696 2015-08-13 17 11.1002/1000/12487 _ *To access the Recommendation, type the URL http:/handle.it
20、u.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 X.696 (08/2015) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecom
21、munications, 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 issuing Recommendations on them with a view to standardizing telecommu
22、nications 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 of ITU-T Recommendations is covered by the proce
23、dure 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“ is used for conciseness to indicate both a telec
24、ommunication 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 the Recommendation is achieved when all of th
25、ese 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 of any party. INTELLECTUAL PROPERTY RIGHTS IT
26、U 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 Property Rights, whether asserted by ITU memb
27、ers 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. However, implementers are cautioned that this may no
28、t 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 whatsoever, without the prior written permission of ITU. Rec. ITU-T X.696
29、(08/2015) iii CONTENTS Page 1 Scope 1 2 Normative references . 1 2.1 Identical Recommendations | International Standards 1 2.2 Additional references 1 3 Definitions 2 3.1 Specification of basic notation 2 3.2 Information object specification 2 3.3 Constraint specification . 2 3.4 Parameterization of
30、 ASN.1 specification 2 3.5 Basic Encoding Rules (BER) 2 3.6 Packed Encoding Rules (PER) 2 3.7 Additional definitions 2 4 Abbreviations . 4 5 Convention . 4 6 Encodings specified by this Recommendation | International Standard . 4 7 Conformance 5 8 General provisions 5 8.1 Use of the type notation 5
31、8.2 Constraints 5 8.3 Type and value model used for encoding 7 8.4 Types to be encoded 7 8.5 Production of a complete OER encoding 7 8.6 Length determinant . 7 8.7 Encoding of tags 8 9 Encoding of Boolean values . 8 10 Encoding of integer values . 8 11 Encoding of enumerated values 9 12 Encoding of
32、real values 10 13 Encoding of bitstring values . 11 13.1 General 11 13.2 Encoding of bitstring types with a fixed size 11 13.3 Encoding of bitstring types with a variable size 11 14 Encoding of octetstring values . 11 15 Encoding of the null value 11 16 Encoding of sequence values 11 17 Encoding of
33、sequence-of values . 13 18 Encoding of set values 13 19 Encoding of set-of values . 13 20 Encoding of choice values 13 21 Encoding of object identifier values . 13 22 Encoding of relative object identifier values 14 23 Encoding of values of the internationalized resource reference type . 14 24 Encod
34、ing of values of the relative internationalized resource reference type 1 4 25 Encoding of values of the embedded-pdv type . 14 26 Encoding of values of the external type . 14 27 Encoding of values of the restricted character string types 14 28 Encoding of values of the unrestricted character string
35、 type 15 iv Rec. ITU-T X.696 (08/2015) Page 29 Encoding of values of the time types 16 29.1 General 16 29.2 Optimized encoding of time subtypes with the Basic=Date property setting 17 29.3 Optimized encoding of time subtypes with the Basic=Time property setting . 18 29.4 Optimized encoding of time s
36、ubtypes with the Basic=Interval property setting . 19 30 Encoding of open type values . 20 31 Canonical Octet Encoding Rules 20 32 Object identifier values referencing the encoding rules . 21 Annex A Example of OER encodings 22 A.1 ASN.1 description of the record structure . 22 A.2 ASN.1 description
37、 of a record value . 22 A.3 BASIC-OER and CANONICAL-OER representation of this record value 22 A.3.1 Hexadecimal view . 23 A.3.2 Descriptive view 23 Annex B Interoperability with NTCIP 1102:2004 25 Bibliography 26 Rec. ITU-T X.696 (08/2015) v Introduction The publications Rec. ITU-T X.680 | ISO/IEC
38、8824-1, Rec. ITU-T X.681 | ISO/IEC 8824-2, Rec. ITU-T X.682 | ISO/IEC 8824-3, Rec. ITU-T X.683 | ISO/IEC 8824-4 together describe Abstract Syntax Notation One (ASN.1), a notation for the definition of messages to be exchanged between peer applications. This Recommendation | International Standard de
39、fines encoding rules that may be applied to values of ASN.1 types which have been defined using the notation specified in the above-mentioned publications. Application of these encoding rules produces a transfer syntax for such values. It is implicit in the specification of these encoding rules that
40、 they are also to be used for decoding. There are more than one set of encoding rules that can be applied to values of ASN.1 types. This Recommendation | International Standard defines two sets of Octet Encoding Rules, so-called because the encoding of every type takes a whole number of octets. Enco
41、ding and decoding data with the Octet Encoding Rules is usually faster than encoding and decoding the same data with the Basic Encoding Rules (described in Rec. ITU-T X.690 | ISO/IEC 8825-1) or the Packed Encoding Rules (described in Rec. ITU-T X.691 | ISO/IEC 8825-2). NOTE The encoding rules specif
42、ied in this Recommendation | International Standard derive from the Octet Encoding Rules (OER) published by American Association of State Highway and Transportation Officials (AASHTO), Institute of Transportation Engineers (ITE) and National Electrical Manufacturers Association (NEMA) as NTCIP 1102:
43、2004. In most practical cases, an implementation of this Recommendation | International Standard can interoperate with an implementation of NTCIP 1102. Clauses 8 to 30 specify the BASIC-OER encoding of ASN.1 types. Clause 31 specifies the CANONICAL-OER encoding of ASN.1 types. Annex A is informative
44、 and contains examples of BASIC-OER and CANONICAL-OER encodings. ISO/IEC 8825-7:2015 (E) Rec. ITU-T X.696 (08/2015) 1 INTERNATIONAL STANDARD ITU-T RECOMMENDATION Information technology ASN.1 encoding rules: Specification of Octet Encoding Rules (OER) 1 Scope This Recommendation | International Stand
45、ard specifies a set of Basic Octet Encoding Rules (BASIC-OER) that may be used to derive a transfer syntax for values of the types defined in Rec. ITU-T X.680 | ISO/IEC 8824-1, Rec. ITU-T X.681 | ISO/IEC 8824-2, Rec. ITU-T X.682 | ISO/IEC 8824-3, Rec. ITU-T X.683 | ISO/IEC 8824-4. This Recommendatio
46、n | International Standard also specifies a set of Canonical Octet Encoding Rules (CANONICAL-OER) which provides constraints on the Basic Octet Encoding Rules and produces a unique encoding for any given ASN.1 value. It is implicit in the specification of these encoding rules that they are also to b
47、e used for decoding. The encoding rules specified in this Recommendation | International Standard: are used at the time of communication; are intended for use in circumstances where encoding/decoding speed is the major concern in the choice of encoding rules; allow the extension of an abstract synta
48、x by addition of extra values for all forms of extensibility described in Rec. ITU-T X.680 | ISO/IEC 8824-1. 2 Normative references The following Recommendations and International Standards contain provisions which, through reference in this text, constitute provisions of this Recommendation | Inter
49、national Standard. At the time of publication, the editions indicated were valid. All Recommendations and Standards are subject to revision, and parties to agreements based on this Recommendation | International Standard are encouraged to investigate the possibility of applying the most recent edition of the Recommendations and Standards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. The Telecommunication Standardization Bureau of t
