ISO/IEC 8825-5:2015
(Main)Information technology — ASN.1 encoding rules: Mapping W3C XML schema definitions into ASN.1 — Part 5:
Information technology — ASN.1 encoding rules: Mapping W3C XML schema definitions into ASN.1 — Part 5:
ISO/IEC 8825-5:2015 specifies two Versions of a mapping from any XSD Schema into an ASN.1 schema. The ASN.1 schema for both Versions support the same semantics and validate the same set of XML documents. ISO/IEC 8825-5:2015 specifies the final XER encoding instructions that are to be applied as part of the defined mapping to ASN.1 types, but does not specify which syntactic form is to be used for the specification of those final XER encoding instructions, or the order or manner of their assignment. NOTE ? Implementers of tools generating these mappings may choose any syntactic form or order of assignment that results in the specified final XER encoding instructions being applied. Examples in this Recommendation | International Standard generally use the type prefix form, but use of an XER Encoding Control Section may be preferred for the mapping of a complete XSD Schema, as a matter of style. There are different ways (syntactically) of assigning XER encoding instructions for use in EXTENDED-XER encodings (for example, use of ASN.1 type prefix encoding instructions or use of an XER encoding control section). The choice of these syntactic forms is a matter of style and is outside the scope of this Recommendation | International Standard.
Technologies de l'information — Règles de codage ASN.1: Mappage en ASN.1 des définitions de schéma XML du W3C — Partie 5:
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Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 8825-5
Third edition
2015-11-15
Information technology — ASN.1
encoding rules: Mapping W3C XML
schema definitions into ASN.1
Technologies de l'information — Règles de codage ASN.1: Mappage en
ASN.1 des définitions de schéma XML du W3C
Reference number
ISO/IEC 8825-5:2015(E)
©
ISO/IEC 2015
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ISO/IEC 8825-5:2015(E)
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ii © ISO/IEC 2015 – All rights reserved
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ISO/IEC 8825-5:2015(E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. 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 mutual 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 accordance 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 Standard 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 third edition cancels and replaces the second edition of ISO/IEC 8825-5:2008 which has been technically
revised. It also incorporates ISO/IEC 8825-5:2008/Cor.1:2012 and ISO/IEC 8825-5:2008.Cor.2:2014.
ISO/IEC 8825-5 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 6, Telecommunications and information exchange between systems, in collaboration with
ITU-T. The identical text is published as ITU-T X.694 (08/2015).
© ISO/IEC 2015 – All rights reserved iii
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International Telecommunication Union
ITU-T X.694
(08/2015)
TELECOMMUNICATION
STANDARDIZATION SECTOR
OF ITU
SERIES X: DATA NETWORKS, OPEN SYSTEM
COMMUNICATIONS AND SECURITY
OSI networking and system aspects – Abstract Syntax
Notation One (ASN.1)
Information technology – ASN.1 encoding rules:
Mapping W3C XML schema definitions into
ASN.1
Recommendation ITU-T X.694
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ITU-T X-SERIES RECOMMENDATIONS
DATA NETWORKS, OPEN SYSTEM COMMUNICATIONS AND SECURITY
PUBLIC DATA NETWORKS
Services and facilities X.1–X.19
Interfaces X.20–X.49
Transmission, signalling and switching X.50–X.89
Network aspects X.90–X.149
Maintenance X.150–X.179
Administrative arrangements X.180–X.199
OPEN SYSTEMS INTERCONNECTION
Model and notation X.200–X.209
Service definitions X.210–X.219
Connection-mode protocol specifications X.220–X.229
Connectionless-mode protocol specifications X.230–X.239
PICS proformas X.240–X.259
Protocol Identification X.260–X.269
Security Protocols X.270–X.279
Layer Managed Objects X.280–X.289
Conformance testing X.290–X.299
INTERWORKING BETWEEN NETWORKS
General X.300–X.349
Satellite data transmission systems X.350–X.369
IP-based networks X.370–X.379
MESSAGE HANDLING SYSTEMS X.400–X.499
DIRECTORY X.500–X.599
OSI NETWORKING AND SYSTEM ASPECTS
Networking X.600–X.629
Efficiency X.630–X.639
Quality of service X.640–X.649
Naming, Addressing and Registration X.650–X.679
Abstract Syntax Notation One (ASN.1) X.680–X.699
OSI MANAGEMENT
Systems management framework and architecture X.700–X.709
Management communication service and protocol X.710–X.719
Structure of management information X.720–X.729
Management functions and ODMA functions X.730–X.799
SECURITY X.800–X.849
OSI APPLICATIONS
Commitment, concurrency and recovery X.850–X.859
Transaction processing X.860–X.879
Remote operations X.880–X.889
Generic applications of ASN.1 X.890–X.899
OPEN DISTRIBUTED PROCESSING X.900–X.999
INFORMATION AND NETWORK SECURITY X.1000–X.1099
SECURE APPLICATIONS AND SERVICES X.1100–X.1199
CYBERSPACE SECURITY X.1200–X.1299
SECURE APPLICATIONS AND SERVICES X.1300–X.1399
CYBERSECURITY INFORMATION EXCHANGE X.1500–X.1599
CLOUD COMPUTING SECURITY X.1600–X.1699
For further details, please refer to the list of ITU-T Recommendations.
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INTERNATIONAL STANDARD ISO/IEC 8825-5
RECOMMENDATION ITU-T X.694
Information technology – ASN.1 encoding rules: Mapping W3C XML
schema definitions into ASN.1
Summary
Recommendation ITU-T X.694 | ISO/IEC 8825-5 defines rules for mapping an XSD Schema (a schema conforming to the
W3C XML Schema specification) to an ASN.1 schema in order to use ASN.1 encoding rules such as the Basic Encoding
Rules (BER), the Distinguished Encoding Rules (DER), the Packed Encoding Rules (PER) or the XML Encoding Rules
(XER) for the transfer of information defined by the XSD Schema.
The use of this Recommendation | International Standard with the ASN.1 Extended XML Encoding Rules (EXTENDED-
XER) provides the same XML representation of values as that defined by the original XSD Schema, but also provides the
ability to encode the specified XML with an efficient binary representation (binary XML). An XML document can be
converted to binary XML (for storage or transfer) using the ASN.1 generated by this mapping, and the resulting binary can
be converted back to the same XML document for further XML processing.
Two versions of the mapping are defined. Version 1 of the mapping was published in 2004, and a Corrigendum was
subsequently issued renaming the types DATE-TIME and DURATION in Annex A (in order to avoid conflict with the
DATE-TIME and DURATION types defined in Rec. ITU-T X.680 | ISO/IEC 8824-1). The Version 2 mapping is more
efficient in two areas: the ASN.1 time types are used rather than VisibleString for mappings of dates and times; the
FastInfoset specification (Rec. ITU-T X.891 | ISO/IEC 24824-1) is used for the mapping of XSD wild-cards. Both these
changes to the mapping provide much more compact binary encodings for the XML specified by the XSD.
NOTE − The specification of the Version 1 mapping (with applicable corrections) will be maintained in the next edition of this
Recommendation | International Standard, but it is expected that subsequent editions will document only the Version 2 mapping.
Application of the ASN.1 extended XML Encoding Rules to both versions of the mapping will produce the same XML
(which is the same as that specified by the XSD). However, application of other ASN.1 encoding rules to the Version 1
mapping results in a verbose character-based encoding of date and time types and of XSD wild-cards, whilst application
of the Version 2 mapping results in a more compact binary encoding using ASN.1 time types and the FastInfoset
specification.
History
*
Edition Recommendation Approval Study Group Unique ID
1.0 ITU-T X.694 2004-01-13 17 11.1002/1000/7106
1.1 ITU-T X.694 (2004) Technical Cor. 1 2005-11-29 17 11.1002/1000/8639
1.2 ITU-T X.694 (2004) Amd. 1 2007-05-29 17 11.1002/1000/9111
2.0 ITU-T X.694 2008-11-13 17 11.1002/1000/9612
2.1 ITU-T X.694 (2008) Cor. 1 2011-10-14 17 11.1002/1000/11382
2.2 ITU-T X.694 (2008) Cor. 2 2014-03-01 17 11.1002/1000/12149
3.0 ITU-T X.694 2015-08-13 17 11.1002/1000/12486
____________________
*
To access the Recommendation, type the URL http://handle.itu.int/ in the address field of your web browser, followed by the
Recommendation's unique ID. For example, http://handle.itu.int/11.1002/1000/11830-en.
Rec. ITU-T X.694 (08/2015) i
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FOREWORD
The International Telecommunication Union (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 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 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-T's 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 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 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 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 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. 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 whatsoever, without the prior
written permission of ITU.
ii Rec. ITU-T X.694 (08/2015)
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CONTENTS
Page
1 Scope . 1
2 Normative references . 1
2.1 Identical Recommendations | International Standards . 1
2.2 Additional references . 2
3 Definitions . 2
3.1 Imported definitions . 2
3.2 Additional definitions . 3
4 Abbreviations . 3
5 Notation . 3
6 Purpose and extent of standardization . 3
7 Mapping XSD Schemas . 4
8 Ignored schema components and properties . 5
9 ASN.1 modules . 6
10 Name conversion . 6
10.1 General . 6
10.2 Generating ASN.1 type definitions that are references to ASN.1 type assignments . 7
10.3 Generating identifiers and type reference names . 7
10.4 Order of the mapping . 9
11 Mapping uses of XSD built-in types . 10
12 Mapping facets . 10
12.1 The length, minLength, and maxLength facets . 11
12.2 The pattern facet. 11
12.3 The whiteSpace facet . 11
12.4 The enumeration facet . 12
12.5 Other facets . 14
13 Mapping simple type definitions . 14
14 Mapping element declarations . 16
15 Mapping attribute declarations . 17
16 Mapping values of simple type definitions . 17
17 Mapping model group definitions . 17
18 Mapping model groups . 17
19 Mapping particles . 18
20 Mapping complex type definitions . 19
21 Mapping wildcards . 20
22 Mapping attribute uses . 22
23 Mapping uses of simple and complex type definitions (general case) . 22
24 Mapping special uses of simple and complex type definitions (substitutable) . 23
25 Mapping special uses of simple and complex type definitions (substitutable, nillable) . 24
26 Mapping special uses of simple type definitions (nillable) . 25
27 Mapping special uses of complex type definitions (nillable) . 26
28 Mapping special uses of element declarations (head of element substitution group) . 27
29 Generating special ASN.1 type assignments for types used in element declarations . 27
30 Generating special ASN.1 type assignments for types belonging to a derivation hierarchy . 29
31 Generating special ASN.1 type assignments for element substitution groups . 29
Annex A – ASN.1 type definitions corresponding to XSD built-in types for the Version 1 mapping . 30
Annex B – ASN.1 type definitions corresponding to XSD built-in types for the Version 2 mapping. 34
Rec. ITU-T X.694 (08/2015) iii
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Page
Annex C – Identification of the XSD module . 38
Annex D – Examples of mappings . 39
D.1 A Schema using simple type definitions . 39
D.2 The corresponding ASN.1 definitions . 40
D.3 Further examples . 41
Annex E – Use of the mapping to provide binary encodings for W3C XML Schema . 61
E.1 Encoding XSD Schemas . 61
E.2 Transfer without using the XSD Schema for Schemas . 61
E.3 Transfer using the XSD Schema for Schemas . 61
iv Rec. ITU-T X.694 (08/2015)
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Introduction
This Recommendation | International Standard specifies Version 1 and Version 2 of a mapping from a W3C XML Schema
definition (an XSD Schema) into an ASN.1 schema. The mappings can be applied to any XSD Schema. Both mappings
specify the generation of one or more ASN.1 modules containing type definitions, together with ASN.1 XER encoding
instructions. These are jointly described as an ASN.1 schema for XML documents. This ASN.1 schema (produced by
either Version of the mapping), when used with the ASN.1 Extended XML Encoding Rules (EXTENDED-XER), can be
used to generate and to validate the same set of W3C XML 1.0 documents as the original XSD Schema. The resulting
ASN.1 types and encodings support the same semantic content as the XSD Schema. Thus ASN.1 tools can be used
interchangeably with XSD tools for the generation and processing of the specified XML documents.
Other standardized ASN.1 encoding rules, such as the Distinguished Encoding Rules (DER) or the Packed Encoding
Rules (PER), can be used in conjunction with this standardized mapping, but produce encodings for Version 2 of the
mapping that differ from (and are less verbose than) those produced by Version 1 for XSD constructs involving dates and
times or wildcards.
The combination of this Recommendation | International Standard with ASN.1 Encoding Rules provides fully-
standardized and vendor-independent compact and canonical binary encodings for data originally defined using an XSD
Schema.
The ASN.1 schema provides a clear separation between the specification of the information content of messages (their
abstract syntax) and the precise form of the XML document (for example, use of attributes instead of elements). This
results in both a clearer and generally a less verbose schema than the original XSD Schema.
Annex A forms an integral part of this Recommendation | International Standard, and is an ASN.1 module containing a
set of ASN.1 type assignments that correspond to each of the XSD built-in types for Version 1 of the mapping. Mappings
of XSD Schemas into ASN.1 schemas either import the type reference names of those type assignments or include the
type definitions in-line.
Annex B also forms an integral part of this Recommendation | International Standard and provides the ASN.1 module for
Version 2 of the mapping.
Annex C does not form an integral part of this Recommendation | International Standard, and summarizes the object
identifier, OID internationalized resource identifier and object descriptor values assigned in this Recommendation |
International Standard.Annex D does not form an integral part of this Recommendation | International Standard, and gives
examples of the mapping of XSD Schemas into ASN.1 schemas.
Annex E does not form an integral part of this Recommendation | International Standard, and describes the use of the
mapping defined in this Recommendation | International Standard, in conjunction with standardized ASN.1 Encoding
Rules, to provide compact and canonical encodings for data defined using an XSD Schema.
Rec. ITU-T X.694 (08/2015) v
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ISO/IEC 8825-5:2015 (E)
INTERNATIONAL STANDARD
ITU-T RECOMMENDATION
Information technology – ASN.1 encoding rules: Mapping W3C XML
schema definitions into ASN.1
1 Scope
This Recommendation | International Standard specifies two Versions of a mapping from any XSD Schema into an ASN.1
schema. The ASN.1 schema for both Versions support the same semantics and validate the same set of XML documents.
This Recommendation | International Standard specifies the final XER encoding instructions that are to be applied as part
of the defined mapping to ASN.1 types, but does not specify which syntactic form is to be used for the specification of
those final XER encoding instructions, or the order or manner of their assignment.
NOTE – Implementers of tools generating these mappings may choose any syntactic form or order of assignment that results in the
specified final XER encoding instructions being applied. Examples in this Recommendation | International Standard generally use
the type prefix form, but use of an XER Encoding Control Section may be preferred for the mapping of a complete XSD Schema,
as a matter of style.
There are different ways (syntactically) of assigning XER encoding instructions for use in EXTENDED-XER encodings
(for example, use of ASN.1 type prefix encoding instructions or use of an XER encoding control section). The choice of
these syntactic forms is a matter of style and is outside the scope of this Recommendation | International Standard.
2 Normative references
The following Recommendations | International Standards and W3C specifications contain provisions which, through
reference in this text, constitute provisions of this Recommendation | International Standard. At the time of publication,
the editions indicated were valid. All Recommendations, International Standards and W3C specifications 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, International Standards and W3C
specifications 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. The
W3C maintains a list of currently valid W3C specifications. The reference to a document within this Recommendation |
International Standard does not give it, as a stand-alone document, the status of a Recommendation or International
Standard.
NOTE – This Recommendation | International Standard is based on ISO/IEC 10646:2003 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
NOTE – The complete set of ASN.1 Recommendations | International Standards are listed below, as they can all be applicable in
particular uses of this Recommendation | International Standard. Where these are not directly referenced in the body of this
Recommendation | International Standard, a † symbol is added to the reference.
– Recommendation ITU-T X.680 (2015) | ISO/IEC 8824-1:2015, Information technology – Abstract Syntax
Notation One (ASN.1): Specification 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 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 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).
– Recommendation ITU-T X.692 (2015) | ISO/IEC 8825-3:2015, Information technology – ASN.1 encoding
rules: Specification of Encoding Control Notation (ECN). †
Rec. ITU-T X.694 (08/2015) 1
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ISO/IEC 8825-5:2015 (E)
– Recommendation ITU-T X.693 (2015) | ISO/IEC 8825-4:2015, Information technology – ASN.1 encoding
rules: XML Encoding Rules (XER).
– Recommendation ITU-T X.891 (2005) | ISO/IEC 24824-1:2007, Information technology – Generic
Applications of ASN.1: Fast Infoset.
2.2 Additional references
– ISO 8601:2004, Data elements and interchange formats – Information interchange – Representation of
dates and times.
– ISO/IEC 10646:2003, Information technology – Universal Multiple-Octet Coded Character Set (UCS).
– W3C XML 1.0:2000, Extensible Markup Language (XML) 1.0 (Second Edition), W3C Recommendation,
Copyright © [6 October 2000] World Wide Web Consortium, (Massachusetts Institute of Technology,
Institut National de Recherche en Informatique et en Automatique, Keio University),
http://www.w3.org/TR/2000/REC-xml-20001006.
– W3C XML Namespaces:1999, Namespaces in XML, W3C Recommendation, Copyright © [14 January
1999] World Wide Web Consortium, (Massachusetts Institute of Technology, Institut National de
Recherche en Informatique et en Automatique, Keio University), http://www.w3.org/TR/1999/REC-xml-
names-19990114.
– W3C XML Information Set:2001, XML Information Set, W3C Recommendation, Copyright ©
[24 October 2001] World Wide Web Consortium (Massachusetts Institute of Technology, Institut National
de Recherche en Informatique et en Automatique, Keio University), http://www.w3.org/TR/2001/REC-xml-
infoset-20011024.
– W3C XML Schema:2001, XML Schema Part 1: Structures, W3C Recommendation, Copyright © [2 May
2001] World Wide Web Consortium, (Massachusetts Institute of Technology, Institut National de
Recherche en Informatique et en Automatique, Keio University), http://www.w3.org/TR/2001/REC-
xmlschema-1-20010502.
– W3C XML Schema:2001, XML Schema Part 2: Datatypes, W3C Recommendation, Copyright © [2 May
2001] World Wide Web Consortium, (Massachusetts Institute of Technology, Institut National de
Recherche en Informatique et en Automatique, Keio University), http://www.w3.org/TR/2001/REC-
xmlschema-2-20010502.
NOTE – When the reference "W3C XML Schema" is used in this Recommendation | International Standard, it
refers to W3C XML Schema Part 1 and W3C XML Schema Part 2.
– IETF RFC 2396 (1998), Uniform Resource Identifiers (URI): Generic Syntax.
– IETF RFC 1766 (1995), Tags for the Identification of Languages.
3 Definitions
3.1 Imported definitions
...
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