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 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 (ASN.1) Information technology
2、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, signalling and switching X.50X.89
3、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 specifications X.230X.239 PICS proformas X
4、.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 MESSAGE HANDLING SYSTEMS X.400X.499
5、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 and architecture X.700X.709 Mana
6、gement 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 Remote operations X.880X.889 G
7、eneric 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 INFORMATION EXCHANGE X.1500X.1599 CL
8、OUD 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 Encoding Rules (OER) Summary R
9、ecommendation 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) and the Packed Encoding Rules (de
10、scribed 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.itu.int/ in the address field of
11、 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 telecommunications, information and c
12、ommunication 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 telecommunications on a worldwide basis
13、. 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 procedure laid down in WTSA Resolut
14、ion 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 telecommunication administration an
15、d 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 these mandatory provisions are m
16、et. 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 RIGHTSITU draws attention to the possib
17、ility 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 members or others outside of the Re
18、commendation 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 not represent the latest informat
19、ion 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 (08/2015) iii CONTENTS Page 1 S
20、cope 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 ASN.1 specification 2 3.5 Basic
21、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 8.2 Constraints 5 8.3 Type and va
22、lue 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 real values 10 13 Encoding of bit
23、string 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 sequence-of values . 13 18 Encodi
24、ng 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 Encoding of values of the relative int
25、ernationalized resource reference type 14 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 type 15 iv Rec. ITU-T X.696 (08/2
26、015) 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 subtypes with the Basic=Interval pr
27、operty 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 of a record value . 22 A.3 BASIC-
28、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 8824-1, Rec. ITU-T X.681 | ISO/IEC
29、 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 defines encoding rules that may be a
30、pplied 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 they are also to be used for deco
31、ding. 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. Encoding and decoding data with the Oc
32、tet 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 specified in this Recommendation | Inter
33、national 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 1102:2004. In most practical cases, an
34、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 and contains examples of BASIC-OE
35、R 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 Standard specifies a set of Basic Octet
36、 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 Recommendation | International Standard also sp
37、ecifies 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 be used for decoding. The encoding
38、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 syntax by addition of extra values for
39、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 | International Standard. At the time of
40、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 Stan
41、dards listed below. Members of IEC and ISO maintain registers of currently valid International Standards. The Telecommunication Standardization Bureau of the ITU maintains a list of currently valid ITU-T Recommendations. NOTE This Recommendation | International Standard is based on ISO/IEC 10646:200
42、3 and the Unicode standard version 3.2.0:2002. It cannot be applied using later versions of these two standards. 2.1 Identical Recommendations | International Standards Recommendation ITU-T X.680 (2015) | ISO/IEC 8824-1:2015, Information technology Abstract Syntax Notation One (ASN.1): Specification
43、 of basic notation. Recommendation ITU-T X.681 (2015) | ISO/IEC 8824-2:2015, Information technology Abstract Syntax Notation One (ASN.1): Information object specification. Recommendation ITU-T X.682 (2015) | ISO/IEC 8824-3:2015, Information technology Abstract Syntax Notation One (ASN.1): Constraint
44、 specification. Recommendation ITU-T X.683 (2015) | ISO/IEC 8824-4:2015, Information technology Abstract Syntax Notation One (ASN.1): Parameterization of ASN.1 specifications. Recommendation ITU-T X.690 (2015) | ISO/IEC 8825-1:2015, Information technology ASN.1 encoding rules: Specification of Basic
45、 Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER). Recommendation ITU-T X.691 (2015) | ISO/IEC 8825-2:2015, Information technology ASN.1 encoding rules: Specification of Packed Encoding Rules (PER). 2.2 Additional references ISO/IEC 2375:2003, Information t
46、echnology Procedure for registration of escape sequences and coded character sets. ISO International Register of Coded Character Sets to be Used with Escape Sequences. ISO/IEC 10646:2003, Information technology Universal Multiple-Octet Coded Character Set (UCS). ISO/IEC 8825-7:2015 (E) 2 Rec. ITU-T
47、X.696 (08/2015) 3 Definitions For the purposes of this Recommendation | International Standard, the following definitions apply. 3.1 Specification of basic notation For the purposes of this Recommendation | International Standard, all the definitions in Rec. ITU-T X.680 | ISO/IEC 8824-1 apply. 3.2 I
48、nformation object specification For the purposes of this Recommendation | International Standard, all the definitions in Rec. ITU-T X.681 | ISO/IEC 8824-2 apply. 3.3 Constraint specification This Recommendation | International Standard makes use of the following terms defined in Rec. ITU-T X.682 | I
49、SO/IEC 8824-3: a) component relation constraint; b) table constraint. 3.4 Parameterization of ASN.1 specification This Recommendation | International Standard makes use of the following term defined in Rec. ITU-T X.683 | ISO/IEC 8824-4: variable constraint. 3.5 Basic Encoding Rules (BER) This Recommendation | International Standard makes use of the following terms defined in Rec. ITU-T X.690 | ISO/IEC 8825-1: a) data value; b) dy
