ISO/IEC 9594-6:2020
(Main)Information technology — Open systems interconnection — Part 6: The Directory: Selected attribute types
Information technology — Open systems interconnection — Part 6: The Directory: Selected attribute types
This document defines a number of attribute types and matching rules which may be found useful across a range of applications of the Directory. Attribute types and matching rules fall into three categories, as described below. Some attribute types and matching rules are used by a wide variety of applications or are understood and/or used by the Directory itself. NOTE 1 ? It is recommended that an attribute type or matching rule defined in this Recommendation | International Standard be used, in preference to the generation of a new one, whenever it is appropriate for the application. NOTE 2 ? The attribute and context types definitions by this Recommendation | International Standard have some associated semantics. Such specifications should not be used in situations where these semantics do not apply. Some attribute types and matching rules are internationally standardized, but are application‑specific. These are defined in the standards associated with the application concerned. Any administrative authority can define its own attribute types and matching rules for any purpose. These are not internationally standardized, and are available to others beyond the administrative authority which created them only through bilateral agreement.
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INTERNATIONAL ISO/IEC
STANDARD 9594-6
Ninth edition
2020-11
Information technology — Open
systems interconnection —
Part 6:
The Directory: Selected attribute types
Reference number
ISO/IEC 9594-6:2020(E)
©
ISO/IEC 2020
---------------------- Page: 1 ----------------------
ISO/IEC 9594-6:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 9594-6:2020(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of document should be noted (see www.iso.org/directives).
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. Details
of any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC list of patent
declarations received (see http://patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the World
Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT),
see www.iso.org/iso/foreword.html.
This document was prepared by ITU-T as ITU-T X.520 (10/2019) and drafted in accordance with
its editorial rules, in collaboration with Joint Technical Committee ISO/IEC JTC 1, Information
technology, Subcommittee SC 6, Telecommunications and information exchange between systems.
This ninth edition cancels and replaces the eighth edition (ISO/IEC 9594-6:2017), which has been
technically revised.
A list of all parts in the ISO/IEC 9594 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body.
A complete listing of these bodies can be found at www.iso.org/members.html.
© ISO/IEC 2020 – All rights reserved iii
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ISO/IEC 9594-6:2020 (E)
CONTENTS
Page
1 Scope . 1
2 Normative references. 1
2.1 Identical Recommendations | International Standards . 1
2.2 Other references . 2
2.3 ISO/IEC Standards . 3
3 Definitions . 3
4 Abbreviations . 3
5 Conventions . 4
6 Definition of selected attribute types . 5
6.1 System attribute types . 5
6.2 Labelling attribute types . 5
6.3 Geographical attribute types . 10
6.4 Organizational attribute types . 12
6.5 Explanatory attribute types . 13
6.6 Postal addressing attribute types . 15
6.7 Telecommunications addressing attribute types . 17
6.8 Preferences attribute types . 20
6.9 OSI application attribute types . 21
6.10 Relational attribute types . 22
6.11 Domain attribute types . 23
6.12 Hierarchical attribute types . 23
6.13 Attributes for applications using tag-based identification . 24
6.14 Simple Authentication attributes held by object entries . 28
6.15 Password policy attributes . 30
6.16 Notification attributes . 34
6.17 LDAP defined attribute types . 39
7 String preparation . 40
7.1 Transcode . 40
7.2 Map . 40
7.3 Normalize . 40
7.4 Prohibit . 40
7.5 Check bidi . 41
7.6 Insignificant Character Removal . 41
8 Definition of matching rules . 41
8.1 String matching rules . 41
8.2 Syntax-based matching rules . 44
8.3 Time matching rules . 47
8.4 First component matching rules . 49
8.5 Word matching rules . 49
8.6 Approximate Matching Rules . 52
8.7 Special Matching Rules . 52
8.8 Zonal Match . 53
8.9 Identity matching rules . 56
8.10 Password policy matching rules . 57
8.11 LDAP defined matching rules . 58
9 Definition of syntaxes. 59
9.1 Directory syntaxes . 59
9.2 IETF syntaxes. 60
10 Definition of Context Types . 66
10.1 Language Context . 66
10.2 Temporal Context . 66
© ISO/IEC 2020 – All rights reserved
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ISO/IEC 9594-6:2020 (E)
Page
10.3 Locale Context . 70
10.4 LDAP Attribute Option Context . 70
Annex A – Selected attribute types in ASN.1 . 72
Annex B – Attribute types for password policy in ASN.1 . 103
Annex C – Upper bounds . 109
Annex D – Alphabetical index of attributes, matching rules and contexts . 110
Annex E – Examples for zonal match matching rules . 113
Annex F – Mapping Object Identifiers and Uniform Resource Names into Distinguished Names . 116
F.1 Scope of this annex . 116
F.2 Object identifier resolution . 116
F.3 Uniform Resource Name (URN) resolution . 117
Annex G – Object identifier based Directory names . 120
G.1 Scope of this annex . 120
G.2 Transformation of object identifiers into Directory names . 120
G.3 The use of object-identifier-based Directory names . 120
Annex H – Amendments and corrigenda . 122
© ISO/IEC 2020 – All rights reserved
vi Rec. ITU-T X.520 (10/2019)
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ISO/IEC 9594-6:2020 (E)
Introduction
This Recommendation | International Standard, together with other Recommendations | International Standards, has been
produced to facilitate the interconnection of information processing systems to provide directory services. A set of such
systems, together with the directory information that they hold, can be viewed as an integrated whole, called the Directory.
The information held by the Directory, collectively known as the Directory Information Base (DIB), is typically used to
facilitate communication between, with or about objects such as application entities, people, terminals, and distribution
lists.
The Directory plays a significant role in Open Systems Interconnection, whose aim is to allow, with a minimum of
technical agreement outside of the interconnection standards themselves, the interconnection of information processing
systems:
– from different manufacturers;
– under different managements;
– of different levels of complexity; and
– of different ages.
This Recommendation | International Standard defines a number of attribute types which may be found useful across a
range of applications of the Directory, as well as a number of standard attribute syntaxes and matching rules. One
particular use for many of the attributes defined herein is in the formation of names, particularly for the classes of objects
defined in Rec. ITU-T X.521 | ISO/IEC 9594-7.
This Recommendation | International Standard provides the foundation frameworks upon which industry profiles can be
defined by other standards groups and industry forums. Many of the features defined as optional in these frameworks may
be mandated for use in certain environments through profiles. This ninth edition technically revises and enhances the
eighth edition of this Recommendation | International Standard.
This ninth edition specifies versions 1 and 2 of the Directory protocols.
Annex A, which is an integral part of this Recommendation | International Standard, provides the ASN.1 notation for the
complete module which defines the attributes, attribute syntaxes and matching rules.
Annex C, which is not an integral part of this Recommendation | International Standard, provides a table of attribute types,
for easy reference.
Annex D, which is not an integral part of this Recommendation | International Standard, provides an example of upper
bounds value constraints. These constraints are not reflected in these Directory Specifications, but are provided as a
reference for those implementations applying these constraints.
Annex E, which is not an integral part of this Recommendation | International Standard, lists alphabetically the attributes
and matching rules defined in this Directory Specification.
Annex F, which is not an integral part of this Recommendation | International Standard, gives examples relevant to the
definition of zonal matching.
Annex G, which is not an integral part of this Recommendation | International Standard, describes how a directory
distinguished name may be based on object identifiers and on Uniform Resource Names (URNs).
Annex H, which is not an integral part of this Recommendation | International Standard, describes an alternative way of
generating directory distinguished based on object identifiers. It contains information retrieved from Rec. ITU-T X.660 |
ISO/IEC 9834-1.
Annex I, which is not an integral part of this Recommendation | International Standard, lists the amendments and defect
reports that have been incorporated to form this edition of this Recommendation | International Standard.
© ISO/IEC 2020 – All rights reserved
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ISO/IEC 9594-6:2020 (E)
INTERNATIONAL STANDARD
RECOMMENDATION ITU-T
Information technology – Open Systems Interconnection –
The Directory: Selected attribute types
SECTION 1 – GENERAL
1 Scope
This Recommendation | International Standard defines a number of attribute types and matching rules which may be
found useful across a range of applications of the Directory.
Attribute types and matching rules fall into three categories, as described below.
Some attribute types and matching rules are used by a wide variety of applications or are understood and/or used by the
Directory itself.
NOTE 1 – It is recommended that an attribute type or matching rule defined in this Recommendation | International Standard be
used, in preference to the generation of a new one, whenever it is appropriate for the application.
NOTE 2 – The attribute and context types definitions by this Recommendation | International Standard have some associated
semantics. Such specifications should not be used in situations where these semantics do not apply.
Some attribute types and matching rules are internationally standardized, but are application-specific. These are defined
in the standards associated with the application concerned.
Any administrative authority can define its own attribute types and matching rules for any purpose. These are not
internationally standardized, and are available to others beyond the administrative authority which created them only
through bilateral agreement.
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 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 the ITU maintains a list of currently valid
ITU-T Recommendations.
2.1 Identical Recommendations | International Standards
– Recommendation ITU-T X.500 (2019) | ISO/IEC 9594-1:2020, Information technology – Open Systems
Interconnection – The Directory: Overview of concepts, models and services.
– Recommendation ITU-T X.501 (2019) | ISO/IEC 9594-2:2020, Information technology – Open Systems
Interconnection – The Directory: Models.
– Recommendation ITU-T X.509 (2019) | ISO/IEC 9594-8:2020, Information technology – Open Systems
Interconnection – The Directory: Public-key and attribute certificate frameworks.
– Recommendation ITU-T X.511 (2019) | ISO/IEC 9594-3:2020, Information technology – Open Systems
Interconnection – The Directory: Abstract service definition.
– Recommendation ITU-T X.518 (2019) | ISO/IEC 9594-4:2020, Information technology – Open Systems
Interconnection – The Directory: Procedures for distributed operation.
– Recommendation ITU-T X.519 (2019) | ISO/IEC 9594-5:2020, Information technology – Open Systems
Interconnection – The Directory: Protocol specifications.
– Recommendation ITU-T X.521 (2019) | ISO/IEC 9594-7:2020, Information technology – Open Systems
Interconnection – The Directory: Selected object classes.
– Recommendation ITU-T X.525 (2019) | ISO/IEC 9594-9:2020, Information technology – Open Systems
Interconnection – The Directory: Replication.
© ISO/IEC 2020 – All rights reserved
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ISO/IEC 9594-6:2020 (E)
– Recommendation ITU-T X.660 (2011) | ISO/IEC 9834-1:2012, Information technology –Procedures for
the operation of object identifier registration authorities: General procedures and top arcs of the
international object identifier tree.
– Recommendation ITU-T X.667 (2012) | ISO/IEC 9834-8:2014, Information technology –Procedures for
the operation of object identifier registration authorities: Generation of universally unique identifiers and
their use in object identifiers.
– Recommendation ITU-T X.668 (2008) | ISO/IEC 9834-9:2008, Information technology – Open Systems
Interconnection – Procedures for the operation of OSI Registration Authorities: Registration of object
identifier arcs for applications and services using tag-based identification.
– 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).
2.2 Other references
– Recommendation ITU-T E.123 (2001), Notation for national and international telephone numbers, e-mail
addresses and web addresses.
– Recommendation ITU-T E.164 (2010), The international public telecommunication numbering plan.
– Recommendation ITU-T F.1 (1998), Operational provisions for the international public telegram service.
– Recommendation ITU-T F.31 (1988), Telegram retransmission system.
– Recommendation ITU-T F.401 (1992), Message handling services: Naming and addressing for public
message handling services.
– Recommendation ITU-T T.30 (2005), Procedures for document facsimile transmission in the general
switched telephone network.
– Recommendation ITU-T T.51 (1992), Latin based coded character sets for telematic services.
– Recommendation ITU-T T.62 (1993), Control procedures for teletex and Group 4 facsimile services.
– Recommendation ITU-T X.121 (2000), International numbering plan for public data networks.
– ISO 3166-1:2013, Codes for the representation of names of countries and their subdivisions – Part 1:
Country codes.
– ISO 3166-3:2013, Codes for the representation of names of countries and their subdivisions – Part 3:
Code for formerly used names of countries.
– ISO 639-2:1998, Codes for the representation of names of languages – Part 2: Alpha-3 code.
– ISO/IEC/IEEE 9945:2009, Information technology – Portable Operating System Interface (POSIX) – Base
Specifications, Issue 7.
– ISO/IEC 15897:2011, Information technology – User interfaces – Procedures for the registration of
cultural elements.
– IETF RFC 3406 (2002), Uniform Resource Names (URN) Namespace Definition Mechanisms.
– IETF RFC 3454 (2002), Preparation of Internationalized Strings ("stringprep").
– IETF RFC 3492 (2003), Punycode: A Bootstring encoding of Unicode for Internationalized Domain
Names in Applications (IDNA).
– IETF RFC 3641 (2003), Generic String Encoding Rules (GSER) for ASN.1 Types.
– IETF RFC 3642 (2003), Common Elements of Generic String Encoding Rules (GSER) Encodings.
– IETF RFC 3672 (2003), Subentries in the Lightweight Directory Access Protocol (LDAP).
– IETF RFC 3986 (2005), Uniform Resource Identifier (URI): Generic Syntax.
© ISO/IEC 2020 – All rights reserved
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ISO/IEC 9594-6:2020 (E)
– IETF RFC 4512 (2006), Lightweight Directory Access Protocol (LDAP): Directory Information Models.
– IETF RFC 4514 (2006); Lightweight Directory Access Protocol (LDAP): String Representation of
Distinguished Names.
– IETF RFC 4517 (2006), Lightweight Directory Access Protocol (LDAP): Syntaxes and Matching Rules.
– IETF RFC 4520 (2006), Internet Assigned Numbers Authority (IANA) Considerations for the Lightweight
Directory Access Protocol (LDAP).
– IETF RFC 4792 (2007), Encoding Instructions for the Generic String Encoding Rules (GSER).
– IETF RFC 5890 (2010), Internationalized Domain Names for Applications (IDNA): Definitions and
Document Framework.
– IETF RFC 5892 (2010), The Unicode Code Points and Internationalized Domain Names for Applications
(IDNA).
– National Imagery and Mapping Agency (NIMA): TR 8350.2 (1984), Department of Defense World
Geodetic System, third edition.
– The Unicode Consortium. The Unicode Standard, Version 4.0.0, defined by: The Unicode Standard,
Version 4.0 (Reading, MA: Addison-Wesley, 2003. ISBN 0-321-18578-1).
– Unicode Standard Annex #15: Unicode Normalization Forms, by Mark Davis and Martin Dürst. An integral
part of The Unicode Standard, Version 4.0.
2.3 ISO/IEC Standards
– ISO/IEC 10646:2017, Information technology – Universal Coded Character Set (UCS).
3 Definitions
For the purposes of this Recommendation | International Standard, the following definitions apply:
The following terms are defined in Rec. ITU-T X.501 | ISO/IEC 9594-2:
a) attribute type;
b) context;
c) matching rule;
d) object class.
4 Abbreviations
For the purposes of this Recommendation | International Standard, the following abbreviations apply:
AFI Application Family Identifier
EPC Electronic Product Code
FQDN Fully-Qualified Domain Name
GSER Generic String Encoding Rules
IDN Internationalized Domain Name
LDAP Lightweight Directory Access Protocol
LDH Letters, Digits, Hyphen
RFID Radio Frequency Identification
RDN Relative Distinguished Name
UII Unique Item Identifier
URL Uniform Resource Locator
URN Uniform Resource Name
UTM Universal Transverse Mercator
UUID Universally Unique Identifier
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ISO/IEC 9594-6:2020 (E)
5 Conventions
The term "Directory Specification" (as in "this Directory Specification") shall be taken to mean Rec. ITU-T X.520 |
ISO/IEC 9594-6. The term "Directory Specifications" shall be taken to mean the Rec. ITU-T X.500 | ISO/IEC 9594-1,
Rec. ITU-T X.501 | ISO/IEC 9594-2, Rec. ITU-T X.511 | ISO/IEC 9594-3, Rec. ITU-T X.518 | ISO/IEC 9594-4, Rec.
ITU-T X.519 | ISO/IEC 9594-5, Rec. ITU-T X.520 | ISO/IEC 9594-6, Rec ITU-T X.521 | ISO/IEC 9594-7 and Rec.
ITU-T X.525 | ISO/IEC 9594-9.
If an International Standard or ITU-T Recommendation is referenced within normal text without an indication of the
edition, the edition shall be taken to be the latest one as specified in the normative references clause.
Prior to year 2020, the parts making up the Directory Specifications progressed together and can therefore collectively be
identified as the Directory Specifications of a specific edition using the format: Rec. ITU-T X.5** (yyyy) | ISO/IEC 9594-
*:yyyy (e.g.; Rec ITU-T X.5** (1993) | ISO/IEC 9594-*:1995).
This Directory Specification makes extensive use of Abstract Syntax Notation One (ASN.1) for the formal specification
of data types and values, as it is specified in Rec. ITU-T X.680 | ISO/IEC 8824-1, ITU-T X.681 | ISO/IEC 8824-2, ITU-
T X.682 | ISO/IEC 8824-3, ITU-T X.683 | ISO/IEC 8824-4 and Rec. ITU-T X.690 | ISO/IEC 8825-1.
This Directory Specification presents ASN.1 notation in the bold Courier New typeface. When ASN.1 types and values
are referenced in normal text, they are differentiated from normal text by presenting them in the bold Courier New
typeface. The names of procedures, typically referenced when specifying the semantics of processing, are differentiated
from normal text by displaying them in bold Times New Roman. Access control permissions are presented in italicized
Times New Roman.
If the items in a list are numbered (as opposed to using "–" or letters), then the items shall be considered steps in a
procedure.
Attribute types, matching rules and
...
INTERNATIONAL ISO/IEC
STANDARD 9594-6
Ninth edition
Information technology — Open
systems interconnection —
Part 6:
The Directory: Selected attribute types
PROOF/ÉPREUVE
Reference number
ISO/IEC 9594-6:2020(E)
© ISO/IEC 2020
---------------------- Page: 1 ----------------------
ISO/IEC 9594-6:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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 an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii PROOF/ÉPREUVE © ISO/IEC 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 9594-6:2020(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of document should be noted (see www.iso.org/directives).
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. Details
of any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www.iso.org/patents) or the IEC list of patent
declarations received (see http://patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the World
Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT),
see www.iso.org/iso/foreword.html.
This document was prepared by ITU-T as ITU-T X.520 (10/2019) and drafted in accordance with its
editorial rules. It was adopted by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 6, Telecommunications and information exchange between systems.
A list of all parts in the ISO/IEC 9594 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
© ISO/IEC 2020 – All rights reserved iii
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ISO/IEC 9594-6:2020 (E)
CONTENTS
Page
1 Scope . 1
2 Normative references. 1
2.1 Identical Recommendations | International Standards . 1
2.2 Other references . 2
2.3 ISO/IEC Standards . 3
3 Definitions . 3
4 Abbreviations . 3
5 Conventions . 4
6 Definition of selected attribute types . 5
6.1 System attribute types . 5
6.2 Labelling attribute types . 5
6.3 Geographical attribute types . 10
6.4 Organizational attribute types . 12
6.5 Explanatory attribute types . 13
6.6 Postal addressing attribute types . 15
6.7 Telecommunications addressing attribute types . 17
6.8 Preferences attribute types . 20
6.9 OSI application attribute types . 21
6.10 Relational attribute types . 22
6.11 Domain attribute types . 23
6.12 Hierarchical attribute types . 23
6.13 Attributes for applications using tag-based identification . 24
6.14 Simple Authentication attributes held by object entries . 28
6.15 Password policy attributes . 30
6.16 Notification attributes . 34
6.17 LDAP defined attribute types . 39
7 String preparation . 40
7.1 Transcode . 40
7.2 Map . 40
7.3 Normalize . 40
7.4 Prohibit . 40
7.5 Check bidi . 41
7.6 Insignificant Character Removal . 41
8 Definition of matching rules . 41
8.1 String matching rules . 41
8.2 Syntax-based matching rules . 44
8.3 Time matching rules . 47
8.4 First component matching rules . 49
8.5 Word matching rules . 49
8.6 Approximate Matching Rules . 52
8.7 Special Matching Rules . 52
8.8 Zonal Match . 53
8.9 Identity matching rules . 56
8.10 Password policy matching rules . 57
8.11 LDAP defined matching rules . 58
9 Definition of syntaxes. 59
9.1 Directory syntaxes . 59
9.2 IETF syntaxes. 60
10 Definition of Context Types . 66
10.1 Language Context . 66
10.2 Temporal Context . 66
© ISO/IEC 2020 – All rights reserved
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ISO/IEC 9594-6:2020 (E)
Page
10.3 Locale Context . 70
10.4 LDAP Attribute Option Context . 70
Annex A – Selected attribute types in ASN.1 . 72
Annex B – Attribute types for password policy in ASN.1 . 103
Annex C – Upper bounds . 109
Annex D – Alphabetical index of attributes, matching rules and contexts . 110
Annex E – Examples for zonal match matching rules . 113
Annex F – Mapping Object Identifiers and Uniform Resource Names into Distinguished Names . 116
F.1 Scope of this annex . 116
F.2 Object identifier resolution . 116
F.3 Uniform Resource Name (URN) resolution . 117
Annex G – Object identifier based Directory names . 120
G.1 Scope of this annex . 120
G.2 Transformation of object identifiers into Directory names . 120
G.3 The use of object-identifier-based Directory names . 120
Annex H – Amendments and corrigenda . 122
© ISO/IEC 2020 – All rights reserved
vi Rec. ITU-T X.520 (10/2019)
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ISO/IEC 9594-6:2020 (E)
Introduction
This Recommendation | International Standard, together with other Recommendations | International Standards, has been
produced to facilitate the interconnection of information processing systems to provide directory services. A set of such
systems, together with the directory information that they hold, can be viewed as an integrated whole, called the Directory.
The information held by the Directory, collectively known as the Directory Information Base (DIB), is typically used to
facilitate communication between, with or about objects such as application entities, people, terminals, and distribution
lists.
The Directory plays a significant role in Open Systems Interconnection, whose aim is to allow, with a minimum of
technical agreement outside of the interconnection standards themselves, the interconnection of information processing
systems:
– from different manufacturers;
– under different managements;
– of different levels of complexity; and
– of different ages.
This Recommendation | International Standard defines a number of attribute types which may be found useful across a
range of applications of the Directory, as well as a number of standard attribute syntaxes and matching rules. One
particular use for many of the attributes defined herein is in the formation of names, particularly for the classes of objects
defined in Rec. ITU-T X.521 | ISO/IEC 9594-7.
This Recommendation | International Standard provides the foundation frameworks upon which industry profiles can be
defined by other standards groups and industry forums. Many of the features defined as optional in these frameworks may
be mandated for use in certain environments through profiles. This ninth edition technically revises and enhances the
eighth edition of this Recommendation | International Standard.
This ninth edition specifies versions 1 and 2 of the Directory protocols.
Annex A, which is an integral part of this Recommendation | International Standard, provides the ASN.1 notation for the
complete module which defines the attributes, attribute syntaxes and matching rules.
Annex C, which is not an integral part of this Recommendation | International Standard, provides a table of attribute types,
for easy reference.
Annex D, which is not an integral part of this Recommendation | International Standard, provides an example of upper
bounds value constraints. These constraints are not reflected in these Directory Specifications, but are provided as a
reference for those implementations applying these constraints.
Annex E, which is not an integral part of this Recommendation | International Standard, lists alphabetically the attributes
and matching rules defined in this Directory Specification.
Annex F, which is not an integral part of this Recommendation | International Standard, gives examples relevant to the
definition of zonal matching.
Annex G, which is not an integral part of this Recommendation | International Standard, describes how a directory
distinguished name may be based on object identifiers and on Uniform Resource Names (URNs).
Annex H, which is not an integral part of this Recommendation | International Standard, describes an alternative way of
generating directory distinguished based on object identifiers. It contains information retrieved from Rec. ITU-T X.660 |
ISO/IEC 9834-1.
Annex I, which is not an integral part of this Recommendation | International Standard, lists the amendments and defect
reports that have been incorporated to form this edition of this Recommendation | International Standard.
© ISO/IEC 2020 – All rights reserved
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ISO/IEC 9594-6:2020 (E)
INTERNATIONAL STANDARD
RECOMMENDATION ITU-T
Information technology – Open Systems Interconnection –
The Directory: Selected attribute types
SECTION 1 – GENERAL
1 Scope
This Recommendation | International Standard defines a number of attribute types and matching rules which may be
found useful across a range of applications of the Directory.
Attribute types and matching rules fall into three categories, as described below.
Some attribute types and matching rules are used by a wide variety of applications or are understood and/or used by the
Directory itself.
NOTE 1 – It is recommended that an attribute type or matching rule defined in this Recommendation | International Standard be
used, in preference to the generation of a new one, whenever it is appropriate for the application.
NOTE 2 – The attribute and context types definitions by this Recommendation | International Standard have some associated
semantics. Such specifications should not be used in situations where these semantics do not apply.
Some attribute types and matching rules are internationally standardized, but are application-specific. These are defined
in the standards associated with the application concerned.
Any administrative authority can define its own attribute types and matching rules for any purpose. These are not
internationally standardized, and are available to others beyond the administrative authority which created them only
through bilateral agreement.
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 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 the ITU maintains a list of currently valid
ITU-T Recommendations.
2.1 Identical Recommendations | International Standards
– Recommendation ITU-T X.500 (2019) | ISO/IEC 9594-1:2020, Information technology – Open Systems
Interconnection – The Directory: Overview of concepts, models and services.
– Recommendation ITU-T X.501 (2019) | ISO/IEC 9594-2:2020, Information technology – Open Systems
Interconnection – The Directory: Models.
– Recommendation ITU-T X.509 (2019) | ISO/IEC 9594-8:2020, Information technology – Open Systems
Interconnection – The Directory: Public-key and attribute certificate frameworks.
– Recommendation ITU-T X.511 (2019) | ISO/IEC 9594-3:2020, Information technology – Open Systems
Interconnection – The Directory: Abstract service definition.
– Recommendation ITU-T X.518 (2019) | ISO/IEC 9594-4:2020, Information technology – Open Systems
Interconnection – The Directory: Procedures for distributed operation.
– Recommendation ITU-T X.519 (2019) | ISO/IEC 9594-5:2020, Information technology – Open Systems
Interconnection – The Directory: Protocol specifications.
– Recommendation ITU-T X.521 (2019) | ISO/IEC 9594-7:2020, Information technology – Open Systems
Interconnection – The Directory: Selected object classes.
– Recommendation ITU-T X.525 (2019) | ISO/IEC 9594-9:2020, Information technology – Open Systems
Interconnection – The Directory: Replication.
© ISO/IEC 2020 – All rights reserved
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ISO/IEC 9594-6:2020 (E)
– Recommendation ITU-T X.660 (2011) | ISO/IEC 9834-1:2012, Information technology –Procedures for
the operation of object identifier registration authorities: General procedures and top arcs of the
international object identifier tree.
– Recommendation ITU-T X.667 (2012) | ISO/IEC 9834-8:2014, Information technology –Procedures for
the operation of object identifier registration authorities: Generation of universally unique identifiers and
their use in object identifiers.
– Recommendation ITU-T X.668 (2008) | ISO/IEC 9834-9:2008, Information technology – Open Systems
Interconnection – Procedures for the operation of OSI Registration Authorities: Registration of object
identifier arcs for applications and services using tag-based identification.
– 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).
2.2 Other references
– Recommendation ITU-T E.123 (2001), Notation for national and international telephone numbers, e-mail
addresses and web addresses.
– Recommendation ITU-T E.164 (2010), The international public telecommunication numbering plan.
– Recommendation ITU-T F.1 (1998), Operational provisions for the international public telegram service.
– Recommendation ITU-T F.31 (1988), Telegram retransmission system.
– Recommendation ITU-T F.401 (1992), Message handling services: Naming and addressing for public
message handling services.
– Recommendation ITU-T T.30 (2005), Procedures for document facsimile transmission in the general
switched telephone network.
– Recommendation ITU-T T.51 (1992), Latin based coded character sets for telematic services.
– Recommendation ITU-T T.62 (1993), Control procedures for teletex and Group 4 facsimile services.
– Recommendation ITU-T X.121 (2000), International numbering plan for public data networks.
– ISO 3166-1:2013, Codes for the representation of names of countries and their subdivisions – Part 1:
Country codes.
– ISO 3166-3:2013, Codes for the representation of names of countries and their subdivisions – Part 3:
Code for formerly used names of countries.
– ISO 639-2:1998, Codes for the representation of names of languages – Part 2: Alpha-3 code.
– ISO/IEC/IEEE 9945:2009, Information technology – Portable Operating System Interface (POSIX) – Base
Specifications, Issue 7.
– ISO/IEC 15897:2011, Information technology – User interfaces – Procedures for the registration of
cultural elements.
– IETF RFC 3406 (2002), Uniform Resource Names (URN) Namespace Definition Mechanisms.
– IETF RFC 3454 (2002), Preparation of Internationalized Strings ("stringprep").
– IETF RFC 3492 (2003), Punycode: A Bootstring encoding of Unicode for Internationalized Domain
Names in Applications (IDNA).
– IETF RFC 3641 (2003), Generic String Encoding Rules (GSER) for ASN.1 Types.
– IETF RFC 3642 (2003), Common Elements of Generic String Encoding Rules (GSER) Encodings.
– IETF RFC 3672 (2003), Subentries in the Lightweight Directory Access Protocol (LDAP).
– IETF RFC 3986 (2005), Uniform Resource Identifier (URI): Generic Syntax.
© ISO/IEC 2020 – All rights reserved
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ISO/IEC 9594-6:2020 (E)
– IETF RFC 4512 (2006), Lightweight Directory Access Protocol (LDAP): Directory Information Models.
– IETF RFC 4514 (2006); Lightweight Directory Access Protocol (LDAP): String Representation of
Distinguished Names.
– IETF RFC 4517 (2006), Lightweight Directory Access Protocol (LDAP): Syntaxes and Matching Rules.
– IETF RFC 4520 (2006), Internet Assigned Numbers Authority (IANA) Considerations for the Lightweight
Directory Access Protocol (LDAP).
– IETF RFC 4792 (2007), Encoding Instructions for the Generic String Encoding Rules (GSER).
– IETF RFC 5890 (2010), Internationalized Domain Names for Applications (IDNA): Definitions and
Document Framework.
– IETF RFC 5892 (2010), The Unicode Code Points and Internationalized Domain Names for Applications
(IDNA).
– National Imagery and Mapping Agency (NIMA): TR 8350.2 (1984), Department of Defense World
Geodetic System, third edition.
– The Unicode Consortium. The Unicode Standard, Version 4.0.0, defined by: The Unicode Standard,
Version 4.0 (Reading, MA: Addison-Wesley, 2003. ISBN 0-321-18578-1).
– Unicode Standard Annex #15: Unicode Normalization Forms, by Mark Davis and Martin Dürst. An integral
part of The Unicode Standard, Version 4.0.
2.3 ISO/IEC Standards
– ISO/IEC 10646:2017, Information technology – Universal Coded Character Set (UCS).
3 Definitions
For the purposes of this Recommendation | International Standard, the following definitions apply:
The following terms are defined in Rec. ITU-T X.501 | ISO/IEC 9594-2:
a) attribute type;
b) context;
c) matching rule;
d) object class.
4 Abbreviations
For the purposes of this Recommendation | International Standard, the following abbreviations apply:
AFI Application Family Identifier
EPC Electronic Product Code
FQDN Fully-Qualified Domain Name
GSER Generic String Encoding Rules
IDN Internationalized Domain Name
LDAP Lightweight Directory Access Protocol
LDH Letters, Digits, Hyphen
RFID Radio Frequency Identification
RDN Relative Distinguished Name
UII Unique Item Identifier
URL Uniform Resource Locator
URN Uniform Resource Name
UTM Universal Transverse Mercator
UUID Universally Unique Identifier
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ISO/IEC 9594-6:2020 (E)
5 Conventions
The term "Directory Specification" (as in "this Directory Specification") shall be taken to mean Rec. ITU-T X.520 |
ISO/IEC 9594-6. The term "Directory Specifications" shall be taken to mean the Rec. ITU-T X.500 | ISO/IEC 9594-1,
Rec. ITU-T X.501 | ISO/IEC 9594-2, Rec. ITU-T X.511 | ISO/IEC 9594-3, Rec. ITU-T X.518 | ISO/IEC 9594-4, Rec.
ITU-T X.519 | ISO/IEC 9594-5, Rec. ITU-T X.520 | ISO/IEC 9594-6, Rec ITU-T X.521 | ISO/IEC 9594-7 and Rec.
ITU-T X.525 | ISO/IEC 9594-9.
If an International Standard or ITU-T Recommendation is referenced within normal text without an indication of the
edition, the edition shall be taken to be the latest one as specified in the normative references clause.
Prior to year 2020, the parts making up the Directory Specifications progressed together and can therefore collectively be
identified as the Directory Specifications of a specific edition using the format: Rec. ITU-T X.5** (yyyy) | ISO/IEC 9594-
*:yyyy (e.g.; Rec ITU-T X.5** (1993) | ISO/IEC 9594-*:1995).
This Directory Specification makes extensive use of Abstract Syntax Notation One (ASN.1) for the formal specification
of data types and values, as it is specified in Rec. ITU-T X.680 | ISO/IEC 8824-1, ITU-T X.681 | ISO/IEC 8824-2, ITU-
T X.682 | ISO/IEC 8824-3, ITU-T X.683 | ISO/IEC 8824-4 and Rec. ITU-T X.690 | ISO/IEC 8825-1.
This Directory Specification presents ASN.1 notation in the bold Courier New typeface. When ASN.1 types and values
are referenced in normal text, they are differentiated from normal text by presenting them in the bold Courier New
typeface. The names of procedures, typically referenced when specifying the semantics of processing, are differentiated
from normal text by displaying them in bold Times New Roman. Access control permissions are presented in italicized
Times New Roman.
If the items in a list are numbered (as opposed to using "–" or letters), then the items shall be considered steps in a
procedure.
Attribute types, matching rules and context types are defined in this Recommendation | International Standard by use of
the ATTRIBUTE
...
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