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Network Working Group                                       S. Legg, Ed.
Request for Comments: 4517                                       eB2Bcom
Obsoletes: 2252, 2256                                          June 2006
Updates: 3698
Category: Standards Track

Lightweight Directory Access Protocol (LDAP):
                      Syntaxes and Matching Rules

Status of This Memo

This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Abstract

Each attribute stored in a Lightweight Directory Access Protocol
   (LDAP) directory, whose values may be transferred in the LDAP
   protocol, has a defined syntax that constrains the structure and
   format of its values.  The comparison semantics for values of a
   syntax are not part of the syntax definition but are instead provided
   through separately defined matching rules.  Matching rules specify an
   argument, an assertion value, which also has a defined syntax.  This
   document defines a base set of syntaxes and matching rules for use in
   defining attributes for LDAP directories.

Table of Contents

1. Introduction ....................................................3
   2. Conventions .....................................................4
   3. Syntaxes ........................................................4
      3.1. General Considerations .....................................5
      3.2. Common Definitions .........................................5
      3.3. Syntax Definitions .........................................6
           3.3.1. Attribute Type Description ..........................6
           3.3.2. Bit String ..........................................6
           3.3.3. Boolean .............................................7
           3.3.4. Country String ......................................7
           3.3.5. Delivery Method .....................................8

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3.3.6. Directory String ....................................8
           3.3.7. DIT Content Rule Description ........................9
           3.3.8. DIT Structure Rule Description .....................10
           3.3.9. DN .................................................10
           3.3.10. Enhanced Guide ....................................11
           3.3.11. Facsimile Telephone Number ........................12
           3.3.12. Fax ...............................................12
           3.3.13. Generalized Time ..................................13
           3.3.14. Guide .............................................14
           3.3.15. IA5 String ........................................15
           3.3.16. Integer ...........................................15
           3.3.17. JPEG ..............................................15
           3.3.18. LDAP Syntax Description ...........................16
           3.3.19. Matching Rule Description .........................16
           3.3.20. Matching Rule Use Description .....................17
           3.3.21. Name and Optional UID .............................17
           3.3.22. Name Form Description .............................18
           3.3.23. Numeric String ....................................18
           3.3.24. Object Class Description ..........................18
           3.3.25. Octet String ......................................19
           3.3.26. OID ...............................................19
           3.3.27. Other Mailbox .....................................20
           3.3.28. Postal Address ....................................20
           3.3.29. Printable String ..................................21
           3.3.30. Substring Assertion ...............................22
           3.3.31. Telephone Number ..................................23
           3.3.32. Teletex Terminal Identifier .......................23
           3.3.33. Telex Number ......................................24
           3.3.34. UTC Time ..........................................24
   4. Matching Rules .................................................25
      4.1. General Considerations ....................................25
      4.2. Matching Rule Definitions .................................27
           4.2.1. bitStringMatch .....................................27
           4.2.2. booleanMatch .......................................28
           4.2.3. caseExactIA5Match ..................................28
           4.2.4. caseExactMatch .....................................29
           4.2.5. caseExactOrderingMatch .............................29
           4.2.6. caseExactSubstringsMatch ...........................30
           4.2.7. caseIgnoreIA5Match .................................30
           4.2.8. caseIgnoreIA5SubstringsMatch .......................31
           4.2.9. caseIgnoreListMatch ................................31
           4.2.10. caseIgnoreListSubstringsMatch .....................32
           4.2.11. caseIgnoreMatch ...................................33
           4.2.12. caseIgnoreOrderingMatch ...........................33
           4.2.13. caseIgnoreSubstringsMatch .........................34
           4.2.14. directoryStringFirstComponentMatch ................34
           4.2.15. distinguishedNameMatch ............................35
           4.2.16. generalizedTimeMatch ..............................36

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4.2.17. generalizedTimeOrderingMatch ......................36
           4.2.18. integerFirstComponentMatch ........................36
           4.2.19. integerMatch ......................................37
           4.2.20. integerOrderingMatch ..............................37
           4.2.21. keywordMatch ......................................38
           4.2.22. numericStringMatch ................................38
           4.2.23. numericStringOrderingMatch ........................39
           4.2.24. numericStringSubstringsMatch ......................39
           4.2.25. objectIdentifierFirstComponentMatch ...............40
           4.2.26. objectIdentifierMatch .............................40
           4.2.27. octetStringMatch ..................................41
           4.2.28. octetStringOrderingMatch ..........................41
           4.2.29. telephoneNumberMatch ..............................42
           4.2.30. telephoneNumberSubstringsMatch ....................42
           4.2.31. uniqueMemberMatch .................................43
           4.2.32. wordMatch .........................................44
   5. Security Considerations ........................................44
   6. Acknowledgements ...............................................44
   7. IANA Considerations ............................................45
   8. References .....................................................46
      8.1. Normative References ......................................46
      8.2. Informative References ....................................48
   Appendix A. Summary of Syntax Object Identifiers ..................49
   Appendix B. Changes from RFC 2252 .................................49

1.  Introduction

Each attribute stored in a Lightweight Directory Access Protocol
   (LDAP) directory [RFC4510], whose values may be transferred in the
   LDAP protocol [RFC4511], has a defined syntax (i.e., data type) that
   constrains the structure and format of its values.  The comparison
   semantics for values of a syntax are not part of the syntax
   definition but are instead provided through separately defined
   matching rules.  Matching rules specify an argument, an assertion
   value, which also has a defined syntax.  This document defines a base
   set of syntaxes and matching rules for use in defining attributes for
   LDAP directories.

Readers are advised to familiarize themselves with the Directory
   Information Models [RFC4512] before reading the rest of this
   document.  Section 3 provides definitions for the base set of LDAP
   syntaxes.  Section 4 provides definitions for the base set of
   matching rules for LDAP.

This document is an integral part of the LDAP technical specification
   [RFC4510], which obsoletes the previously defined LDAP technical
   specification, RFC 3377, in its entirety.

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Sections 4, 5, and 7 of RFC 2252 are obsoleted by [RFC4512].  The
   remainder of RFC 2252 is obsoleted by this document.  Sections 6 and
   8 of RFC 2256 are obsoleted by this document.  The remainder of RFC
   2256 is obsoleted by [RFC4519] and [RFC4512].  All but Section 2.11
   of RFC 3698 is obsoleted by this document.

A number of schema elements that were included in the previous
   revision of the LDAP technical specification are not included in this
   revision of LDAP.  Public Key Infrastructure schema elements are now
   specified in [RFC4523].  Unless reintroduced in future technical
   specifications, the remainder are to be considered Historic.

The changes with respect to RFC 2252 are described in Appendix B of
   this document.

2.  Conventions

In this document, the key words "MUST", "MUST NOT", "REQUIRED",
   "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",
   and "OPTIONAL" are to be interpreted as described in BCP 14, RFC 2119
   [RFC2119].

Syntax definitions are written according to the <SyntaxDescription>
   ABNF [RFC4234] rule specified in [RFC4512], and matching rule
   definitions are written according to the <MatchingRuleDescription>
   ABNF rule specified in [RFC4512], except that the syntax and matching
   rule definitions provided in this document are line-wrapped for
   readability.  When such definitions are transferred as attribute
   values in the LDAP protocol (e.g., as values of the ldapSyntaxes and
   matchingRules attributes [RFC4512], respectively), then those values
   would not contain line breaks.

3.  Syntaxes

Syntax definitions constrain the structure of attribute values stored
   in an LDAP directory, and determine the representation of attribute
   and assertion values transferred in the LDAP protocol.

Syntaxes that are required for directory operation, or that are in
   common use, are specified in this section.  Servers SHOULD recognize
   all the syntaxes listed in this document, but are not required to
   otherwise support them, and MAY recognise or support other syntaxes.
   However, the definition of additional arbitrary syntaxes is
   discouraged since it will hinder interoperability.  Client and server
   implementations typically do not have the ability to dynamically
   recognize new syntaxes.

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3.1.  General Considerations

The description of each syntax specifies how attribute or assertion
   values conforming to the syntax are to be represented when
   transferred in the LDAP protocol [RFC4511].  This representation is
   referred to as the LDAP-specific encoding to distinguish it from
   other methods of encoding attribute values (e.g., the Basic Encoding
   Rules (BER) encoding [BER] used by X.500 [X.500] directories).

The LDAP-specific encoding of a given attribute syntax always
   produces octet-aligned values.  To the greatest extent possible,
   encoding rules for LDAP syntaxes should produce character strings
   that can be displayed with little or no translation by clients
   implementing LDAP.  However, clients MUST NOT assume that the LDAP-
   specific encoding of a value of an unrecognized syntax is a human-
   readable character string.  There are a few cases (e.g., the JPEG
   syntax) when it is not reasonable to produce a human-readable
   representation.

Each LDAP syntax is uniquely identified with an object identifier
   [ASN.1] represented in the dotted-decimal format (short descriptive
   names are not defined for syntaxes).  These object identifiers are
   not intended to be displayed to users.  The object identifiers for
   the syntaxes defined in this document are summarized in Appendix A.

A suggested minimum upper bound on the number of characters in an
   attribute value with a string-based syntax, or the number of octets
   in a value for all other syntaxes, MAY be indicated by appending the
   bound inside of curly braces following the syntax's OBJECT IDENTIFIER
   in an attribute type definition (see the <noidlen> rule in
   [RFC4512]).  Such a bound is not considered part of the syntax
   identifier.

For example, "1.3.6.1.4.1.1466.115.121.1.15{64}" in an attribute
   definition suggests that the directory server will allow a value of
   the attribute to be up to 64 characters long, although it may allow
   longer character strings.  Note that a single character of the
   Directory String syntax can be encoded in more than one octet, since
   UTF-8 [RFC3629] is a variable-length encoding.  Therefore, a 64-
   character string may be more than 64 octets in length.

3.2.  Common Definitions

The following ABNF rules are used in a number of the syntax
   definitions in Section 3.3.

PrintableCharacter = ALPHA / DIGIT / SQUOTE / LPAREN / RPAREN /
                           PLUS / COMMA / HYPHEN / DOT / EQUALS /

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SLASH / COLON / QUESTION / SPACE
      PrintableString    = 1*PrintableCharacter
      IA5String          = *(%x00-7F)
      SLASH              = %x2F  ; forward slash ("/")
      COLON              = %x3A  ; colon (":")
      QUESTION           = %x3F  ; question mark ("?")

The <ALPHA>, <DIGIT>, <SQUOTE>, <LPAREN>, <RPAREN>, <PLUS>, <COMMA>,
   <HYPHEN>, <DOT>, <EQUALS>, and <SPACE> rules are defined in
   [RFC4512].

3.3.  Syntax Definitions

3.3.1.  Attribute Type Description

A value of the Attribute Type Description syntax is the definition of
   an attribute type.  The LDAP-specific encoding of a value of this
   syntax is defined by the <AttributeTypeDescription> rule in
   [RFC4512].

For example, the following definition of the createTimestamp
      attribute type from [RFC4512] is also a value of the Attribute
      Type Description syntax.  (Note: Line breaks have been added for
      readability; they are not part of the value when transferred in
      protocol.)

( 2.5.18.1 NAME 'createTimestamp'
            EQUALITY generalizedTimeMatch
            ORDERING generalizedTimeOrderingMatch
            SYNTAX 1.3.6.1.4.1.1466.115.121.1.24
            SINGLE-VALUE NO-USER-MODIFICATION
            USAGE directoryOperation )

The LDAP definition for the Attribute Type Description syntax is:

( 1.3.6.1.4.1.1466.115.121.1.3 DESC 'Attribute Type Description' )

This syntax corresponds to the AttributeTypeDescription ASN.1 type
   from [X.501].

3.3.2.  Bit String

A value of the Bit String syntax is a sequence of binary digits.  The
   LDAP-specific encoding of a value of this syntax is defined by the
   following ABNF:

BitString    = SQUOTE *binary-digit SQUOTE "B"
      binary-digit = "0" / "1"

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The <SQUOTE> rule is defined in [RFC4512].

Example:
         '0101111101'B

The LDAP definition for the Bit String syntax is:

( 1.3.6.1.4.1.1466.115.121.1.6 DESC 'Bit String' )

This syntax corresponds to the BIT STRING ASN.1 type from [ASN.1].

3.3.3.  Boolean

A value of the Boolean syntax is one of the Boolean values, true or
   false.  The LDAP-specific encoding of a value of this syntax is
   defined by the following ABNF:

Boolean = "TRUE" / "FALSE"

The LDAP definition for the Boolean syntax is:

( 1.3.6.1.4.1.1466.115.121.1.7 DESC 'Boolean' )

This syntax corresponds to the BOOLEAN ASN.1 type from [ASN.1].

3.3.4.  Country String

A value of the Country String syntax is one of the two-character
   codes from ISO 3166 [ISO3166] for representing a country.  The LDAP-
   specific encoding of a value of this syntax is defined by the
   following ABNF:

CountryString  = 2(PrintableCharacter)

The <PrintableCharacter> rule is defined in Section 3.2.

Examples:

US
         AU

The LDAP definition for the Country String syntax is:

( 1.3.6.1.4.1.1466.115.121.1.11 DESC 'Country String' )

This syntax corresponds to the following ASN.1 type from [X.520]:

PrintableString (SIZE (2)) -- ISO 3166 codes only

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3.3.5.  Delivery Method

A value of the Delivery Method syntax is a sequence of items that
   indicate, in preference order, the service(s) by which an entity is
   willing and/or capable of receiving messages.  The LDAP-specific
   encoding of a value of this syntax is defined by the following ABNF:

DeliveryMethod = pdm *( WSP DOLLAR WSP pdm )

pdm = "any" / "mhs" / "physical" / "telex" / "teletex" /
            "g3fax" / "g4fax" / "ia5" / "videotex" / "telephone"

The <WSP> and <DOLLAR> rules are defined in [RFC4512].

Example:
         telephone $ videotex

The LDAP definition for the Delivery Method syntax is:

( 1.3.6.1.4.1.1466.115.121.1.14 DESC 'Delivery Method' )

This syntax corresponds to the following ASN.1 type from [X.520]:

SEQUENCE OF INTEGER {
          any-delivery-method     (0),
          mhs-delivery            (1),
          physical-delivery       (2),
          telex-delivery          (3),
          teletex-delivery        (4),
          g3-facsimile-delivery   (5),
          g4-facsimile-delivery   (6),
          ia5-terminal-delivery   (7),
          videotex-delivery       (8),
          telephone-delivery      (9) }

3.3.6.  Directory String

A value of the Directory String syntax is a string of one or more
   arbitrary characters from the Universal Character Set (UCS) [UCS].  A
   zero-length character string is not permitted.  The LDAP-specific
   encoding of a value of this syntax is the UTF-8 encoding [RFC3629] of
   the character string.  Such encodings conform to the following ABNF:

DirectoryString = 1*UTF8

The <UTF8> rule is defined in [RFC4512].

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Example:
         This is a value of Directory String containing #!%#@.

Servers and clients MUST be prepared to receive arbitrary UCS code
   points, including code points outside the range of printable ASCII
   and code points not presently assigned to any character.

Attribute type definitions using the Directory String syntax should
   not restrict the format of Directory String values, e.g., by
   requiring that the character string conforms to specific patterns
   described by ABNF.  A new syntax should be defined in such cases.

The LDAP definition for the Directory String syntax is:

( 1.3.6.1.4.1.1466.115.121.1.15 DESC 'Directory String' )

This syntax corresponds to the DirectoryString parameterized ASN.1
   type from [X.520].

The DirectoryString ASN.1 type allows a choice between the
   TeletexString, PrintableString, or UniversalString ASN.1 types from
   [ASN.1].  However, note that the chosen alternative is not indicated
   in the LDAP-specific encoding of a Directory String value.

Implementations that convert Directory String values from the LDAP-
   specific encoding to the BER encoding used by X.500 must choose an
   alternative that permits the particular characters in the string and
   must convert the characters from the UTF-8 encoding into the
   character encoding of the chosen alternative.  When converting
   Directory String values from the BER encoding to the LDAP-specific
   encoding, the characters must be converted from the character
   encoding of the chosen alternative into the UTF-8 encoding.  These
   conversions SHOULD be done in a manner consistent with the Transcode
   step of the string preparation algorithms [RFC4518] for LDAP.

3.3.7.  DIT Content Rule Description

A value of the DIT Content Rule Description syntax is the definition
   of a DIT (Directory Information Tree) content rule.  The LDAP-
   specific encoding of a value of this syntax is defined by the
   <DITContentRuleDescription> rule in [RFC4512].

Example:
         ( 2.5.6.4 DESC 'content rule for organization'
            NOT ( x121Address $ telexNumber ) )

Note: A line break has been added for readability; it is not part
      of the value.

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The LDAP definition for the DIT Content Rule Description syntax is:

( 1.3.6.1.4.1.1466.115.121.1.16
         DESC 'DIT Content Rule Description' )

This syntax corresponds to the DITContentRuleDescription ASN.1 type
   from [X.501].

3.3.8.  DIT Structure Rule Description

A value of the DIT Structure Rule Description syntax is the
   definition of a DIT structure rule.  The LDAP-specific encoding of a
   value of this syntax is defined by the <DITStructureRuleDescription>
   rule in [RFC4512].

Example:
         ( 2 DESC 'organization structure rule' FORM 2.5.15.3 )

The LDAP definition for the DIT Structure Rule Description syntax is:

( 1.3.6.1.4.1.1466.115.121.1.17
         DESC 'DIT Structure Rule Description' )

This syntax corresponds to the DITStructureRuleDescription ASN.1 type
   from [X.501].

3.3.9.  DN

A value of the DN syntax is the (purported) distinguished name (DN)
   of an entry [RFC4512].  The LDAP-specific encoding of a value of this
   syntax is defined by the <distinguishedName> rule from the string
   representation of distinguished names [RFC4514].

Examples (from [RFC4514]):
         UID=jsmith,DC=example,DC=net
         OU=Sales+CN=J. Smith,DC=example,DC=net
         CN=John Smith\, III,DC=example,DC=net
         CN=Before\0dAfter,DC=example,DC=net
         1.3.6.1.4.1.1466.0=#04024869,DC=example,DC=com
         CN=Lu\C4\8Di\C4\87

The LDAP definition for the DN syntax is:

( 1.3.6.1.4.1.1466.115.121.1.12 DESC 'DN' )

The DN syntax corresponds to the DistinguishedName ASN.1 type from
   [X.501].  Note that a BER encoded distinguished name (as used by
   X.500) re-encoded into the LDAP-specific encoding is not necessarily

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reversible to the original BER encoding since the chosen string type
   in any DirectoryString components of the distinguished name is not
   indicated in the LDAP-specific encoding of the distinguished name
   (see Section 3.3.6).

3.3.10.  Enhanced Guide

A value of the Enhanced Guide syntax suggests criteria, which consist
   of combinations of attribute types and filter operators, to be used
   in constructing filters to search for entries of particular object
   classes.  The Enhanced Guide syntax improves upon the Guide syntax by
   allowing the recommended depth of the search to be specified.

The LDAP-specific encoding of a value of this syntax is defined by
   the following ABNF:

EnhancedGuide = object-class SHARP WSP criteria WSP
                         SHARP WSP subset
      object-class  = WSP oid WSP
      subset        = "baseobject" / "oneLevel" / "wholeSubtree"

criteria   = and-term *( BAR and-term )
      and-term   = term *( AMPERSAND term )
      term       = EXCLAIM term /
                   attributetype DOLLAR match-type /
                   LPAREN criteria RPAREN /
                   true /
                   false
      match-type = "EQ" / "SUBSTR" / "GE" / "LE" / "APPROX"
      true       = "?true"
      false      = "?false"
      BAR        = %x7C  ; vertical bar ("|")
      AMPERSAND  = %x26  ; ampersand ("&")
      EXCLAIM    = %x21  ; exclamation mark ("!")

The <SHARP>, <WSP>, <oid>, <LPAREN>, <RPAREN>, <attributetype>, and
   <DOLLAR> rules are defined in [RFC4512].

The LDAP definition for the Enhanced Guide syntax is:

( 1.3.6.1.4.1.1466.115.121.1.21 DESC 'Enhanced Guide' )

Example:
         person#(sn$EQ)#oneLevel

The Enhanced Guide syntax corresponds to the EnhancedGuide ASN.1 type
   from [X.520].  The EnhancedGuide type references the Criteria ASN.1
   type, also from [X.520].  The <true> rule, above, represents an empty

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"and" expression in a value of the Criteria type.  The <false> rule,
   above, represents an empty "or" expression in a value of the Criteria
   type.

3.3.11.  Facsimile Telephone Number

A value of the Facsimile Telephone Number syntax is a subscriber
   number of a facsimile device on the public switched telephone
   network.  The LDAP-specific encoding of a value of this syntax is
   defined by the following ABNF:

fax-number       = telephone-number *( DOLLAR fax-parameter )
      telephone-number = PrintableString
      fax-parameter    = "twoDimensional" /
                         "fineResolution" /
                         "unlimitedLength" /
                         "b4Length" /
                         "a3Width" /
                         "b4Width" /
                         "uncompressed"

The <telephone-number> is a string of printable characters that
   complies with the internationally agreed format for representing
   international telephone numbers [E.123].  The <PrintableString> rule
   is defined in Section 3.2.  The <DOLLAR> rule is defined in
   [RFC4512].

The LDAP definition for the Facsimile Telephone Number syntax is:

( 1.3.6.1.4.1.1466.115.121.1.22 DESC 'Facsimile Telephone Number')

The Facsimile Telephone Number syntax corresponds to the
   FacsimileTelephoneNumber ASN.1 type from [X.520].

3.3.12.  Fax

A value of the Fax syntax is an image that is produced using the
   Group 3 facsimile process [FAX] to duplicate an object, such as a
   memo.  The LDAP-specific encoding of a value of this syntax is the
   string of octets for a Group 3 Fax image as defined in [FAX].

The LDAP definition for the Fax syntax is:

( 1.3.6.1.4.1.1466.115.121.1.23 DESC 'Fax' )

The ASN.1 type corresponding to the Fax syntax is defined as follows,
   assuming EXPLICIT TAGS:

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Fax ::= CHOICE {
        g3-facsimile  [3] G3FacsimileBodyPart
      }

The G3FacsimileBodyPart ASN.1 type is defined in [X.420].

3.3.13.  Generalized Time

A value of the Generalized Time syntax is a character string
   representing a date and time.  The LDAP-specific encoding of a value
   of this syntax is a restriction of the format defined in [ISO8601],
   and is described by the following ABNF:

GeneralizedTime = century year month day hour
                           [ minute [ second / leap-second ] ]
                           [ fraction ]
                           g-time-zone

century = 2(%x30-39) ; "00" to "99"
      year    = 2(%x30-39) ; "00" to "99"
      month   =   ( %x30 %x31-39 ) ; "01" (January) to "09"
                / ( %x31 %x30-32 ) ; "10" to "12"
      day     =   ( %x30 %x31-39 )    ; "01" to "09"
                / ( %x31-32 %x30-39 ) ; "10" to "29"
                / ( %x33 %x30-31 )    ; "30" to "31"
      hour    = ( %x30-31 %x30-39 ) / ( %x32 %x30-33 ) ; "00" to "23"
      minute  = %x30-35 %x30-39                        ; "00" to "59"

second      = ( %x30-35 %x30-39 ) ; "00" to "59"
      leap-second = ( %x36 %x30 )       ; "60"

fraction        = ( DOT / COMMA ) 1*(%x30-39)
      g-time-zone     = %x5A  ; "Z"
                        / g-differential
      g-differential  = ( MINUS / PLUS ) hour [ minute ]
      MINUS           = %x2D  ; minus sign ("-")

The <DOT>, <COMMA>, and <PLUS> rules are defined in [RFC4512].

The above ABNF allows character strings that do not represent valid
   dates (in the Gregorian calendar) and/or valid times (e.g., February
   31, 1994).  Such character strings SHOULD be considered invalid for
   this syntax.

The time value represents coordinated universal time (equivalent to
   Greenwich Mean Time) if the "Z" form of <g-time-zone> is used;
   otherwise, the value represents a local time in the time zone
   indicated by <g-differential>.  In the latter case, coordinated

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universal time can be calculated by subtracting the differential from
   the local time.  The "Z" form of <g-time-zone> SHOULD be used in
   preference to <g-differential>.

If <minute> is omitted, then <fraction> represents a fraction of an
   hour; otherwise, if <second> and <leap-second> are omitted, then
   <fraction> represents a fraction of a minute; otherwise, <fraction>
   represents a fraction of a second.

Examples:
         199412161032Z
         199412160532-0500

Both example values represent the same coordinated universal time:
   10:32 AM, December 16, 1994.

The LDAP definition for the Generalized Time syntax is:

( 1.3.6.1.4.1.1466.115.121.1.24 DESC 'Generalized Time' )

This syntax corresponds to the GeneralizedTime ASN.1 type from
   [ASN.1], with the constraint that local time without a differential
   SHALL NOT be used.

3.3.14.  Guide

A value of the Guide syntax suggests criteria, which consist of
   combinations of attribute types and filter operators, to be used in
   constructing filters to search for entries of particular object
   classes.  The Guide syntax is obsolete and should not be used for
   defining new attribute types.

The LDAP-specific encoding of a value of this syntax is defined by
   the following ABNF:

Guide = [ object-class SHARP ] criteria

The <object-class> and <criteria> rules are defined in Section
   3.3.10.  The <SHARP> rule is defined in [RFC4512].

The LDAP definition for the Guide syntax is:

( 1.3.6.1.4.1.1466.115.121.1.25 DESC 'Guide' )

The Guide syntax corresponds to the Guide ASN.1 type from [X.520].

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3.3.15.  IA5 String

A value of the IA5 String syntax is a string of zero, one, or more
   characters from International Alphabet 5 (IA5) [T.50], the
   international version of the ASCII character set.  The LDAP-specific
   encoding of a value of this syntax is the unconverted string of
   characters, which conforms to the <IA5String> rule in Section 3.2.

The LDAP definition for the IA5 String syntax is:

( 1.3.6.1.4.1.1466.115.121.1.26 DESC 'IA5 String' )

This syntax corresponds to the IA5String ASN.1 type from [ASN.1].

3.3.16.  Integer

A value of the Integer syntax is a whole number of unlimited
   magnitude.  The LDAP-specific encoding of a value of this syntax is
   the optionally signed decimal digit character string representation
   of the number (for example, the number 1321 is represented by the
   character string "1321").  The encoding is defined by the following
   ABNF:

Integer = ( HYPHEN LDIGIT *DIGIT ) / number

The <HYPHEN>, <LDIGIT>, <DIGIT>, and <number> rules are defined in
   [RFC4512].

The LDAP definition for the Integer syntax is:

( 1.3.6.1.4.1.1466.115.121.1.27 DESC 'INTEGER' )

This syntax corresponds to the INTEGER ASN.1 type from [ASN.1].

3.3.17.  JPEG

A value of the JPEG syntax is an image in the JPEG File Interchange
   Format (JFIF), as described in [JPEG].  The LDAP-specific encoding of
   a value of this syntax is the sequence of octets of the JFIF encoding
   of the image.

The LDAP definition for the JPEG syntax is:

( 1.3.6.1.4.1.1466.115.121.1.28 DESC 'JPEG' )

The JPEG syntax corresponds to the following ASN.1 type:

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JPEG ::= OCTET STRING (CONSTRAINED BY
                   { -- contents octets are an image in the --
                     -- JPEG File Interchange Format -- })

3.3.18.  LDAP Syntax Description

A value of the LDAP Syntax Description syntax is the description of
   an LDAP syntax.  The LDAP-specific encoding of a value of this syntax
   is defined by the <SyntaxDescription> rule in [RFC4512].

The LDAP definition for the LDAP Syntax Description syntax is:

( 1.3.6.1.4.1.1466.115.121.1.54 DESC 'LDAP Syntax Description' )

The above LDAP definition for the LDAP Syntax Description syntax is
   itself a legal value of the LDAP Syntax Description syntax.

The ASN.1 type corresponding to the LDAP Syntax Description syntax is
   defined as follows, assuming EXPLICIT TAGS:

LDAPSyntaxDescription ::= SEQUENCE {
          identifier      OBJECT IDENTIFIER,
          description     DirectoryString { ub-schema } OPTIONAL }

The DirectoryString parameterized ASN.1 type is defined in [X.520].

The value of ub-schema (an integer) is implementation defined.  A
   non-normative definition appears in [X.520].

3.3.19.  Matching Rule Description

A value of the Matching Rule Description syntax is the definition of
   a matching rule.  The LDAP-specific encoding of a value of this
   syntax is defined by the <MatchingRuleDescription> rule in [RFC4512].

Example:
         ( 2.5.13.2 NAME 'caseIgnoreMatch'
            SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )

Note: A line break has been added for readability; it is not part of
   the syntax.

The LDAP definition for the Matching Rule Description syntax is:

( 1.3.6.1.4.1.1466.115.121.1.30 DESC 'Matching Rule Description' )

This syntax corresponds to the MatchingRuleDescription ASN.1 type
   from [X.501].

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3.3.20.  Matching Rule Use Description

A value of the Matching Rule Use Description syntax indicates the
   attribute types to which a matching rule may be applied in an
   extensibleMatch search filter [RFC4511].  The LDAP-specific encoding
   of a value of this syntax is defined by the
   <MatchingRuleUseDescription> rule in [RFC4512].

Example:
         ( 2.5.13.16 APPLIES ( givenName $ surname ) )

The LDAP definition for the Matching Rule Use Description syntax is:

( 1.3.6.1.4.1.1466.115.121.1.31
         DESC 'Matching Rule Use Description' )

This syntax corresponds to the MatchingRuleUseDescription ASN.1 type
   from [X.501].

3.3.21.  Name and Optional UID

A value of the Name and Optional UID syntax is the distinguished name
   [RFC4512] of an entity optionally accompanied by a unique identifier
   that serves to differentiate the entity from others with an identical
   distinguished name.

The LDAP-specific encoding of a value of this syntax is defined by
   the following ABNF:

NameAndOptionalUID = distinguishedName [ SHARP BitString ]

The <BitString> rule is defined in Section 3.3.2.  The
   <distinguishedName> rule is defined in [RFC4514].  The <SHARP> rule
   is defined in [RFC4512].

Note that although the '#' character may occur in the string
   representation of a distinguished name, no additional escaping of
   this character is performed when a <distinguishedName> is encoded in
   a <NameAndOptionalUID>.

Example:
         1.3.6.1.4.1.1466.0=#04024869,O=Test,C=GB#'0101'B

The LDAP definition for the Name and Optional UID syntax is:

( 1.3.6.1.4.1.1466.115.121.1.34 DESC 'Name And Optional UID' )

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This syntax corresponds to the NameAndOptionalUID ASN.1 type from
   [X.520].

3.3.22.  Name Form Description

A value of the Name Form Description syntax is the definition of a
   name form, which regulates how entries may be named.  The LDAP-
   specific encoding of a value of this syntax is defined by the
   <NameFormDescription> rule in [RFC4512].

Example:
         ( 2.5.15.3 NAME 'orgNameForm' OC organization MUST o )

The LDAP definition for the Name Form Description syntax is:

( 1.3.6.1.4.1.1466.115.121.1.35 DESC 'Name Form Description' )

This syntax corresponds to the NameFormDescription ASN.1 type from
   [X.501].

3.3.23.  Numeric String

A value of the Numeric String syntax is a sequence of one or more
   numerals and spaces.  The LDAP-specific encoding of a value of this
   syntax is the unconverted string of characters, which conforms to the
   following ABNF:

NumericString = 1*(DIGIT / SPACE)

The <DIGIT> and <SPACE> rules are defined in [RFC4512].

Example:
         15 079 672 281

The LDAP definition for the Numeric String syntax is:

( 1.3.6.1.4.1.1466.115.121.1.36 DESC 'Numeric String' )

This syntax corresponds to the NumericString ASN.1 type from [ASN.1].

3.3.24.  Object Class Description

A value of the Object Class Description syntax is the definition of
   an object class.  The LDAP-specific encoding of a value of this
   syntax is defined by the <ObjectClassDescription> rule in [RFC4512].

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Example:
         ( 2.5.6.2 NAME 'country' SUP top STRUCTURAL MUST c
            MAY ( searchGuide $ description ) )

Note: A line break has been added for readability; it is not part of
   the syntax.

The LDAP definition for the Object Class Description syntax is:

( 1.3.6.1.4.1.1466.115.121.1.37 DESC 'Object Class Description' )

This syntax corresponds to the ObjectClassDescription ASN.1 type from
   [X.501].

3.3.25.  Octet String

A value of the Octet String syntax is a sequence of zero, one, or
   more arbitrary octets.  The LDAP-specific encoding of a value of this
   syntax is the unconverted sequence of octets, which conforms to the
   following ABNF:

OctetString = *OCTET

The <OCTET> rule is defined in [RFC4512].  Values of this syntax are
   not generally human-readable.

The LDAP definition for the Octet String syntax is:

( 1.3.6.1.4.1.1466.115.121.1.40 DESC 'Octet String' )

This syntax corresponds to the OCTET STRING ASN.1 type from [ASN.1].

3.3.26.  OID

A value of the OID syntax is an object identifier: a sequence of two
   or more non-negative integers that uniquely identify some object or
   item of specification.  Many of the object identifiers used in LDAP
   also have IANA registered names [RFC4520].

The LDAP-specific encoding of a value of this syntax is defined by
   the <oid> rule in [RFC4512].

Examples:
         1.2.3.4
         cn

The LDAP definition for the OID syntax is:

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( 1.3.6.1.4.1.1466.115.121.1.38 DESC 'OID' )

This syntax corresponds to the OBJECT IDENTIFIER ASN.1 type from
   [ASN.1].

3.3.27.  Other Mailbox

A value of the Other Mailbox syntax identifies an electronic mailbox,
   in a particular named mail system.  The LDAP-specific encoding of a
   value of this syntax is defined by the following ABNF:

OtherMailbox = mailbox-type DOLLAR mailbox
      mailbox-type = PrintableString
      mailbox      = IA5String

The <mailbox-type> rule represents the type of mail system in which
   the mailbox resides (for example, "MCIMail"), and <mailbox> is the
   actual mailbox in the mail system described by <mailbox-type>.  The
   <PrintableString> and <IA5String> rules are defined in Section 3.2.
   The <DOLLAR> rule is defined in [RFC4512].

The LDAP definition for the Other Mailbox syntax is:

( 1.3.6.1.4.1.1466.115.121.1.39 DESC 'Other Mailbox' )

The ASN.1 type corresponding to the Other Mailbox syntax is defined
   as follows, assuming EXPLICIT TAGS:

OtherMailbox ::= SEQUENCE {
          mailboxType  PrintableString,
          mailbox      IA5String
      }

3.3.28.  Postal Address

A value of the Postal Address syntax is a sequence of strings of one
   or more arbitrary UCS characters, which form an address in a physical
   mail system.

The LDAP-specific encoding of a value of this syntax is defined by
   the following ABNF:

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PostalAddress = line *( DOLLAR line )
      line          = 1*line-char
      line-char     = %x00-23
                      / (%x5C "24")  ; escaped "$"
                      / %x25-5B
                      / (%x5C "5C")  ; escaped "\"
                      / %x5D-7F
                      / UTFMB

Each character string (i.e., <line>) of a postal address value is
   encoded as a UTF-8 [RFC3629] string, except that "\" and "$"
   characters, if they occur in the string, are escaped by a "\"
   character followed by the two hexadecimal digit code for the
   character.  The <DOLLAR> and <UTFMB> rules are defined in [RFC4512].

Many servers limit the postal address to no more than six lines of no
   more than thirty characters each.

Example:
         1234 Main St.$Anytown, CA 12345$USA
         \241,000,000 Sweepstakes$PO Box 1000000$Anytown, CA 12345$USA

The LDAP definition for the Postal Address syntax is:

( 1.3.6.1.4.1.1466.115.121.1.41 DESC 'Postal Address' )

This syntax corresponds to the PostalAddress ASN.1 type from [X.520];
   that is

PostalAddress ::= SEQUENCE SIZE(1..ub-postal-line) OF
          DirectoryString { ub-postal-string }

The values of ub-postal-line and ub-postal-string (both integers) are
   implementation defined.  Non-normative definitions appear in [X.520].

3.3.29.  Printable String

A value of the Printable String syntax is a string of one or more
   latin alphabetic, numeric, and selected punctuation characters as
   specified by the <PrintableCharacter> rule in Section 3.2.

The LDAP-specific encoding of a value of this syntax is the
   unconverted string of characters, which conforms to the
   <PrintableString> rule in Section 3.2.

Example:
         This is a PrintableString.

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The LDAP definition for the PrintableString syntax is:

( 1.3.6.1.4.1.1466.115.121.1.44 DESC 'Printable String' )

This syntax corresponds to the PrintableString ASN.1 type from
   [ASN.1].

3.3.30.  Substring Assertion

A value of the Substring Assertion syntax is a sequence of zero, one,
   or more character substrings used as an argument for substring
   extensible matching of character string attribute values; i.e., as
   the matchValue of a MatchingRuleAssertion [RFC4511].  Each substring
   is a string of one or more arbitrary characters from the Universal
   Character Set (UCS) [UCS].  A zero-length substring is not permitted.

The LDAP-specific encoding of a value of this syntax is defined by
   the following ABNF:

SubstringAssertion = [ initial ] any [ final ]

initial  = substring
      any      = ASTERISK *(substring ASTERISK)
      final    = substring
      ASTERISK = %x2A  ; asterisk ("*")

substring           = 1*substring-character
      substring-character = %x00-29
                            / (%x5C "2A")  ; escaped "*"
                            / %x2B-5B
                            / (%x5C "5C")  ; escaped "\"
                            / %x5D-7F
                            / UTFMB

Each <substring> of a Substring Assertion value is encoded as a UTF-8
   [RFC3629] string, except that "\" and "*" characters, if they occur
   in the substring, are escaped by a "\" character followed by the two
   hexadecimal digit code for the character.

The Substring Assertion syntax is used only as the syntax of
   assertion values in the extensible match.  It is not used as an
   attribute syntax, or in the SubstringFilter [RFC4511].

The LDAP definition for the Substring Assertion syntax is:

( 1.3.6.1.4.1.1466.115.121.1.58 DESC 'Substring Assertion' )

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This syntax corresponds to the SubstringAssertion ASN.1 type from
   [X.520].

3.3.31.  Telephone Number

A value of the Telephone Number syntax is a string of printable
   characters that complies with the internationally agreed format for
   representing international telephone numbers [E.123].

The LDAP-specific encoding of a value of this syntax is the
   unconverted string of characters, which conforms to the
   <PrintableString> rule in Section 3.2.

Examples:
         +1 512 315 0280
         +1-512-315-0280
         +61 3 9896 7830

The LDAP definition for the Telephone Number syntax is:

( 1.3.6.1.4.1.1466.115.121.1.50 DESC 'Telephone Number' )

The Telephone Number syntax corresponds to the following ASN.1 type
   from [X.520]:

PrintableString (SIZE(1..ub-telephone-number))

The value of ub-telephone-number (an integer) is implementation
   defined.  A non-normative definition appears in [X.520].

3.3.32.  Teletex Terminal Identifier

A value of this syntax specifies the identifier and (optionally)
   parameters of a teletex terminal.

The LDAP-specific encoding of a value of this syntax is defined by
   the following ABNF:

teletex-id = ttx-term *(DOLLAR ttx-param)
      ttx-term   = PrintableString          ; terminal identifier
      ttx-param  = ttx-key COLON ttx-value  ; parameter
      ttx-key    = "graphic" / "control" / "misc" / "page" / "private"
      ttx-value  = *ttx-value-octet

ttx-value-octet = %x00-23
                        / (%x5C "24")  ; escaped "$"
                        / %x25-5B
                        / (%x5C "5C")  ; escaped "\"

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/ %x5D-FF

The <PrintableString> and <COLON> rules are defined in Section 3.2.
   The <DOLLAR> rule is defined in [RFC4512].

The LDAP definition for the Teletex Terminal Identifier syntax is:

( 1.3.6.1.4.1.1466.115.121.1.51
         DESC 'Teletex Terminal Identifier' )

This syntax corresponds to the TeletexTerminalIdentifier ASN.1 type
   from [X.520].

3.3.33.  Telex Number

A value of the Telex Number syntax specifies the telex number,
   country code, and answerback code of a telex terminal.

The LDAP-specific encoding of a value of this syntax is defined by
   the following ABNF:

telex-number  = actual-number DOLLAR country-code
                         DOLLAR answerback
      actual-number = PrintableString
      country-code  = PrintableString
      answerback    = PrintableString

The <PrintableString> rule is defined in Section 3.2.  The <DOLLAR>
   rule is defined in [RFC4512].

The LDAP definition for the Telex Number syntax is:

( 1.3.6.1.4.1.1466.115.121.1.52 DESC 'Telex Number' )

This syntax corresponds to the TelexNumber ASN.1 type from [X.520].

3.3.34.  UTC Time

A value of the UTC Time syntax is a character string representing a
   date and time to a precision of one minute or one second.  The year
   is given as a two-digit number.  The LDAP-specific encoding of a
   value of this syntax follows the format defined in [ASN.1] for the
   UTCTime type and is described by the following ABNF:

UTCTime         = year month day hour minute [ second ]
                           [ u-time-zone ]
      u-time-zone     = %x5A  ; "Z"
                        / u-differential

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u-differential  = ( MINUS / PLUS ) hour minute

The <year>, <month>, <day>, <hour>, <minute>, <second>, and <MINUS>
   rules are defined in Section 3.3.13.  The <PLUS> rule is defined in
   [RFC4512].

The above ABNF allows character strings that do not represent valid
   dates (in the Gregorian calendar) and/or valid times.  Such character
   strings SHOULD be considered invalid for this syntax.

The time value represents coordinated universal time if the "Z" form
   of <u-time-zone> is used; otherwise, the value represents a local
   time.  In the latter case, if <u-differential> is provided, then
   coordinated universal time can be calculated by subtracting the
   differential from the local time.  The <u-time-zone> SHOULD be
   present in time values, and the "Z" form of <u-time-zone> SHOULD be
   used in preference to <u-differential>.

The LDAP definition for the UTC Time syntax is:

( 1.3.6.1.4.1.1466.115.121.1.53 DESC 'UTC Time' )

Note: This syntax is deprecated in favor of the Generalized Time
   syntax.

The UTC Time syntax corresponds to the UTCTime ASN.1 type from
   [ASN.1].

4.  Matching Rules

Matching rules are used by directory implementations to compare
   attribute values against assertion values when performing Search and
   Compare operations [RFC4511].  They are also used when comparing a
   purported distinguished name [RFC4512] with the name of an entry.
   When modifying entries, matching rules are used to identify values to
   be deleted and to prevent an attribute from containing two equal
   values.

Matching rules that are required for directory operation, or that are
   in common use, are specified in this section.

4.1.  General Considerations

A matching rule is applied to attribute values through an
   AttributeValueAssertion or MatchingRuleAssertion [RFC4511].  The
   conditions under which an AttributeValueAssertion or
   MatchingRuleAssertion evaluates to Undefined are specified elsewhere
   [RFC4511].  If an assertion is not Undefined, then the result of the

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assertion is the result of applying the selected matching rule.  A
   matching rule evaluates to TRUE, and in some cases Undefined, as
   specified in the description of the matching rule; otherwise, it
   evaluates to FALSE.

Each assertion contains an assertion value.  The definition of each
   matching rule specifies the syntax for the assertion value.  The
   syntax of the assertion value is typically, but not necessarily, the
   same as the syntax of the attribute values to which the matching rule
   may be applied.  Note that an AssertionValue in a SubstringFilter
   [RFC4511] conforms to the assertion syntax of the equality matching
   rule for the attribute type rather than to the assertion syntax of
   the substrings matching rule for the attribute type.  Conceptually,
   the entire SubstringFilter is converted into an assertion value of
   the substrings matching rule prior to applying the rule.

The definition of each matching rule indicates the attribute syntaxes
   to which the rule may be applied, by specifying conditions the
   corresponding ASN.1 type of a candidate attribute syntax must
   satisfy.  These conditions are also satisfied if the corresponding
   ASN.1 type is a tagged or constrained derivative of the ASN.1 type
   explicitly mentioned in the rule description (i.e., ASN.1 tags and
   constraints are ignored in checking applicability), or is an
   alternative reference notation for the explicitly mentioned type.
   Each rule description lists, as examples of applicable attribute
   syntaxes, the complete list of the syntaxes defined in this document
   to which the matching rule applies.  A matching rule may be
   applicable to additional syntaxes defined in other documents if those
   syntaxes satisfy the conditions on the corresponding ASN.1 type.

The description of each matching rule indicates whether the rule is
   suitable for use as the equality matching rule (EQUALITY), ordering
   matching rule (ORDERING), or substrings matching rule (SUBSTR) in an
   attribute type definition [RFC4512].

Each matching rule is uniquely identified with an object identifier.
   The definition of a matching rule should not subsequently be changed.
   If a change is desirable, then a new matching rule with a different
   object identifier should be defined instead.

Servers MAY implement the wordMatch and keywordMatch matching rules,
   but they SHOULD implement the other matching rules in Section 4.2.
   Servers MAY implement additional matching rules.

Servers that implement the extensibleMatch filter SHOULD allow the
   matching rules listed in Section 4.2 to be used in the
   extensibleMatch filter and SHOULD allow matching rules to be used
   with all attribute types known to the server, where the assertion

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syntax of the matching rule is the same as the value syntax of the
   attribute.

Servers MUST publish, in the matchingRules attribute, the definitions
   of matching rules referenced by values of the attributeTypes and
   matchingRuleUse attributes in the same subschema entry.  Other
   unreferenced matching rules MAY be published in the matchingRules
   attribute.

If the server supports the extensibleMatch filter, then the server
   MAY use the matchingRuleUse attribute to indicate the applicability
   (in an extensibleMatch filter) of selected matching rules to
   nominated attribute types.

4.2.  Matching Rule Definitions

Nominated character strings in assertion and attribute values are
   prepared according to the string preparation algorithms [RFC4518] for
   LDAP when evaluating the following matching rules:

numericStringMatch,
      numericStringSubstringsMatch,
      caseExactMatch,
      caseExactOrderingMatch,
      caseExactSubstringsMatch,
      caseExactIA5Match,
      caseIgnoreIA5Match,
      caseIgnoreIA5SubstringsMatch,
      caseIgnoreListMatch,
      caseIgnoreListSubstringsMatch,
      caseIgnoreMatch,
      caseIgnoreOrderingMatch,
      caseIgnoreSubstringsMatch,
      directoryStringFirstComponentMatch,
      telephoneNumberMatch,
      telephoneNumberSubstringsMatch and
      wordMatch.

The Transcode, Normalize, Prohibit, and Check bidi steps are the same
   for each of the matching rules.  However, the Map and Insignificant
   Character Handling steps depend on the specific rule, as detailed in
   the description of these matching rules in the sections that follow.

4.2.1.  bitStringMatch

The bitStringMatch rule compares an assertion value of the Bit String
   syntax to an attribute value of a syntax (e.g., the Bit String
   syntax) whose corresponding ASN.1 type is BIT STRING.

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If the corresponding ASN.1 type of the attribute syntax does not have
   a named bit list [ASN.1] (which is the case for the Bit String
   syntax), then the rule evaluates to TRUE if and only if the attribute
   value has the same number of bits as the assertion value and the bits
   match on a bitwise basis.

If the corresponding ASN.1 type does have a named bit list, then
   bitStringMatch operates as above, except that trailing zero bits in
   the attribute and assertion values are treated as absent.

The LDAP definition for the bitStringMatch rule is:

( 2.5.13.16 NAME 'bitStringMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.6 )

The bitStringMatch rule is an equality matching rule.

4.2.2.  booleanMatch

The booleanMatch rule compares an assertion value of the Boolean
   syntax to an attribute value of a syntax (e.g., the Boolean syntax)
   whose corresponding ASN.1 type is BOOLEAN.

The rule evaluates to TRUE if and only if the attribute value and the
   assertion value are both TRUE or both FALSE.

The LDAP definition for the booleanMatch rule is:

( 2.5.13.13 NAME 'booleanMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.7 )

The booleanMatch rule is an equality matching rule.

4.2.3.  caseExactIA5Match

The caseExactIA5Match rule compares an assertion value of the IA5
   String syntax to an attribute value of a syntax (e.g., the IA5 String
   syntax) whose corresponding ASN.1 type is IA5String.

The rule evaluates to TRUE if and only if the prepared attribute
   value character string and the prepared assertion value character
   string have the same number of characters and corresponding
   characters have the same code point.

In preparing the attribute value and assertion value for comparison,
   characters are not case folded in the Map preparation step, and only
   Insignificant Space Handling is applied in the Insignificant
   Character Handling step.

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The LDAP definition for the caseExactIA5Match rule is:

( 1.3.6.1.4.1.1466.109.114.1 NAME 'caseExactIA5Match'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

The caseExactIA5Match rule is an equality matching rule.

4.2.4.  caseExactMatch

The caseExactMatch rule compares an assertion value of the Directory
   String syntax to an attribute value of a syntax (e.g., the Directory
   String, Printable String, Country String, or Telephone Number syntax)
   whose corresponding ASN.1 type is DirectoryString or one of the
   alternative string types of DirectoryString, such as PrintableString
   (the other alternatives do not correspond to any syntax defined in
   this document).

The LDAP definition for the caseExactMatch rule is:

( 2.5.13.5 NAME 'caseExactMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )

The caseExactMatch rule is an equality matching rule.

4.2.5.  caseExactOrderingMatch

The caseExactOrderingMatch rule compares an assertion value of the
   Directory String syntax to an attribute value of a syntax (e.g., the
   Directory String, Printable String, Country String, or Telephone
   Number syntax) whose corresponding ASN.1 type is DirectoryString or
   one of its alternative string types.

The rule evaluates to TRUE if and only if, in the code point
   collation order, the prepared attribute value character string
   appears earlier than the prepared assertion value character string;
   i.e., the attribute value is "less than" the assertion value.

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The LDAP definition for the caseExactOrderingMatch rule is:

( 2.5.13.6 NAME 'caseExactOrderingMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )

The caseExactOrderingMatch rule is an ordering matching rule.

4.2.6.  caseExactSubstringsMatch

The caseExactSubstringsMatch rule compares an assertion value of the
   Substring Assertion syntax to an attribute value of a syntax (e.g.,
   the Directory String, Printable String, Country String, or Telephone
   Number syntax) whose corresponding ASN.1 type is DirectoryString or
   one of its alternative string types.

The rule evaluates to TRUE if and only if (1) the prepared substrings
   of the assertion value match disjoint portions of the prepared
   attribute value character string in the order of the substrings in
   the assertion value, (2) an <initial> substring, if present, matches
   the beginning of the prepared attribute value character string, and
   (3) a <final> substring, if present, matches the end of the prepared
   attribute value character string.  A prepared substring matches a
   portion of the prepared attribute value character string if
   corresponding characters have the same code point.

In preparing the attribute value and assertion value substrings for
   comparison, characters are not case folded in the Map preparation
   step, and only Insignificant Space Handling is applied in the
   Insignificant Character Handling step.

The LDAP definition for the caseExactSubstringsMatch rule is:

( 2.5.13.7 NAME 'caseExactSubstringsMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )

The caseExactSubstringsMatch rule is a substrings matching rule.

4.2.7.  caseIgnoreIA5Match

The caseIgnoreIA5Match rule compares an assertion value of the IA5
   String syntax to an attribute value of a syntax (e.g., the IA5 String
   syntax) whose corresponding ASN.1 type is IA5String.

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In preparing the attribute value and assertion value for comparison,
   characters are case folded in the Map preparation step, and only
   Insignificant Space Handling is applied in the Insignificant
   Character Handling step.

The LDAP definition for the caseIgnoreIA5Match rule is:

( 1.3.6.1.4.1.1466.109.114.2 NAME 'caseIgnoreIA5Match'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.26 )

The caseIgnoreIA5Match rule is an equality matching rule.

4.2.8.  caseIgnoreIA5SubstringsMatch

The caseIgnoreIA5SubstringsMatch rule compares an assertion value of
   the Substring Assertion syntax to an attribute value of a syntax
   (e.g., the IA5 String syntax) whose corresponding ASN.1 type is
   IA5String.

In preparing the attribute value and assertion value substrings for
   comparison, characters are case folded in the Map preparation step,
   and only Insignificant Space Handling is applied in the Insignificant
   Character Handling step.

( 1.3.6.1.4.1.1466.109.114.3 NAME 'caseIgnoreIA5SubstringsMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )

The caseIgnoreIA5SubstringsMatch rule is a substrings matching rule.

4.2.9.  caseIgnoreListMatch

The caseIgnoreListMatch rule compares an assertion value that is a
   sequence of strings to an attribute value of a syntax (e.g., the

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Postal Address syntax) whose corresponding ASN.1 type is a SEQUENCE
   OF the DirectoryString ASN.1 type.

The rule evaluates to TRUE if and only if the attribute value and the
   assertion value have the same number of strings and corresponding
   strings (by position) match according to the caseIgnoreMatch matching
   rule.

In [X.520], the assertion syntax for this matching rule is defined to
   be:

SEQUENCE OF DirectoryString {ub-match}

That is, it is different from the corresponding type for the Postal
   Address syntax.  The choice of the Postal Address syntax for the
   assertion syntax of the caseIgnoreListMatch in LDAP should not be
   seen as limiting the matching rule to apply only to attributes with
   the Postal Address syntax.

The LDAP definition for the caseIgnoreListMatch rule is:

( 2.5.13.11 NAME 'caseIgnoreListMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.41 )

The caseIgnoreListMatch rule is an equality matching rule.

4.2.10.  caseIgnoreListSubstringsMatch

The caseIgnoreListSubstringsMatch rule compares an assertion value of
   the Substring Assertion syntax to an attribute value of a syntax
   (e.g., the Postal Address syntax) whose corresponding ASN.1 type is a
   SEQUENCE OF the DirectoryString ASN.1 type.

The rule evaluates to TRUE if and only if the assertion value
   matches, per the caseIgnoreSubstringsMatch rule, the character string
   formed by concatenating the strings of the attribute value, except
   that none of the <initial>, <any>, or <final> substrings of the
   assertion value are considered to match a substring of the
   concatenated string which spans more than one of the original strings
   of the attribute value.

Note that, in terms of the LDAP-specific encoding of the Postal
   Address syntax, the concatenated string omits the <DOLLAR> line
   separator and the escaping of "\" and "$" characters.

The LDAP definition for the caseIgnoreListSubstringsMatch rule is:

( 2.5.13.12 NAME 'caseIgnoreListSubstringsMatch'

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SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )

The caseIgnoreListSubstringsMatch rule is a substrings matching rule.

4.2.11.  caseIgnoreMatch

The caseIgnoreMatch rule compares an assertion value of the Directory
   String syntax to an attribute value of a syntax (e.g., the Directory
   String, Printable String, Country String, or Telephone Number syntax)
   whose corresponding ASN.1 type is DirectoryString or one of its
   alternative string types.

The LDAP definition for the caseIgnoreMatch rule is:

( 2.5.13.2 NAME 'caseIgnoreMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )

The caseIgnoreMatch rule is an equality matching rule.

4.2.12.  caseIgnoreOrderingMatch

The caseIgnoreOrderingMatch rule compares an assertion value of the
   Directory String syntax to an attribute value of a syntax (e.g., the
   Directory String, Printable String, Country String, or Telephone
   Number syntax) whose corresponding ASN.1 type is DirectoryString or
   one of its alternative string types.

The LDAP definition for the caseIgnoreOrderingMatch rule is:

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( 2.5.13.3 NAME 'caseIgnoreOrderingMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )

The caseIgnoreOrderingMatch rule is an ordering matching rule.

4.2.13.  caseIgnoreSubstringsMatch

The caseIgnoreSubstringsMatch rule compares an assertion value of the
   Substring Assertion syntax to an attribute value of a syntax (e.g.,
   the Directory String, Printable String, Country String, or Telephone
   Number syntax) whose corresponding ASN.1 type is DirectoryString or
   one of its alternative string types.

The LDAP definition for the caseIgnoreSubstringsMatch rule is:

( 2.5.13.4 NAME 'caseIgnoreSubstringsMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )

The caseIgnoreSubstringsMatch rule is a substrings matching rule.

4.2.14.  directoryStringFirstComponentMatch

The directoryStringFirstComponentMatch rule compares an assertion
   value of the Directory String syntax to an attribute value of a
   syntax whose corresponding ASN.1 type is a SEQUENCE with a mandatory
   first component of the DirectoryString ASN.1 type.

Note that the assertion syntax of this matching rule differs from the
   attribute syntax of attributes for which this is the equality
   matching rule.

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The rule evaluates to TRUE if and only if the assertion value matches
   the first component of the attribute value using the rules of
   caseIgnoreMatch.

The LDAP definition for the directoryStringFirstComponentMatch
   matching rule is:

( 2.5.13.31 NAME 'directoryStringFirstComponentMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )

The directoryStringFirstComponentMatch rule is an equality matching
   rule.  When using directoryStringFirstComponentMatch to compare two
   attribute values (of an applicable syntax), an assertion value must
   first be derived from one of the attribute values.  An assertion
   value can be derived from an attribute value by taking the first
   component of that attribute value.

4.2.15.  distinguishedNameMatch

The distinguishedNameMatch rule compares an assertion value of the DN
   syntax to an attribute value of a syntax (e.g., the DN syntax) whose
   corresponding ASN.1 type is DistinguishedName.

The rule evaluates to TRUE if and only if the attribute value and the
   assertion value have the same number of relative distinguished names
   and corresponding relative distinguished names (by position) are the
   same.  A relative distinguished name (RDN) of the assertion value is
   the same as an RDN of the attribute value if and only if they have
   the same number of attribute value assertions and each attribute
   value assertion (AVA) of the first RDN is the same as the AVA of the
   second RDN with the same attribute type.  The order of the AVAs is
   not significant.  Also note that a particular attribute type may
   appear in at most one AVA in an RDN.  Two AVAs with the same
   attribute type are the same if their values are equal according to
   the equality matching rule of the attribute type.  If one or more of
   the AVA comparisons evaluate to Undefined and the remaining AVA
   comparisons return TRUE then the distinguishedNameMatch rule
   evaluates to Undefined.

The LDAP definition for the distinguishedNameMatch rule is:

( 2.5.13.1 NAME 'distinguishedNameMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.12 )

The distinguishedNameMatch rule is an equality matching rule.

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4.2.16.  generalizedTimeMatch

The generalizedTimeMatch rule compares an assertion value of the
   Generalized Time syntax to an attribute value of a syntax (e.g., the
   Generalized Time syntax) whose corresponding ASN.1 type is
   GeneralizedTime.

The rule evaluates to TRUE if and only if the attribute value
   represents the same universal coordinated time as the assertion
   value.  If a time is specified with the minutes or seconds absent,
   then the number of minutes or seconds (respectively) is assumed to be
   zero.

The LDAP definition for the generalizedTimeMatch rule is:

( 2.5.13.27 NAME 'generalizedTimeMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 )

The generalizedTimeMatch rule is an equality matching rule.

4.2.17.  generalizedTimeOrderingMatch

The generalizedTimeOrderingMatch rule compares the time ordering of
   an assertion value of the Generalized Time syntax to an attribute
   value of a syntax (e.g., the Generalized Time syntax) whose
   corresponding ASN.1 type is GeneralizedTime.

The rule evaluates to TRUE if and only if the attribute value
   represents a universal coordinated time that is earlier than the
   universal coordinated time represented by the assertion value.

The LDAP definition for the generalizedTimeOrderingMatch rule is:

( 2.5.13.28 NAME 'generalizedTimeOrderingMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.24 )

The generalizedTimeOrderingMatch rule is an ordering matching rule.

4.2.18.  integerFirstComponentMatch

The integerFirstComponentMatch rule compares an assertion value of
   the Integer syntax to an attribute value of a syntax (e.g., the DIT
   Structure Rule Description syntax) whose corresponding ASN.1 type is
   a SEQUENCE with a mandatory first component of the INTEGER ASN.1
   type.

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Note that the assertion syntax of this matching rule differs from the
   attribute syntax of attributes for which this is the equality
   matching rule.

The rule evaluates to TRUE if and only if the assertion value and the
   first component of the attribute value are the same integer value.

The LDAP definition for the integerFirstComponentMatch matching rule
   is:

( 2.5.13.29 NAME 'integerFirstComponentMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 )

The integerFirstComponentMatch rule is an equality matching rule.
   When using integerFirstComponentMatch to compare two attribute values
   (of an applicable syntax), an assertion value must first be derived
   from one of the attribute values.  An assertion value can be derived
   from an attribute value by taking the first component of that
   attribute value.

4.2.19.  integerMatch

The integerMatch rule compares an assertion value of the Integer
   syntax to an attribute value of a syntax (e.g., the Integer syntax)
   whose corresponding ASN.1 type is INTEGER.

The rule evaluates to TRUE if and only if the attribute value and the
   assertion value are the same integer value.

The LDAP definition for the integerMatch matching rule is:

( 2.5.13.14 NAME 'integerMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 )

The integerMatch rule is an equality matching rule.

4.2.20.  integerOrderingMatch

The integerOrderingMatch rule compares an assertion value of the
   Integer syntax to an attribute value of a syntax (e.g., the Integer
   syntax) whose corresponding ASN.1 type is INTEGER.

The rule evaluates to TRUE if and only if the integer value of the
   attribute value is less than the integer value of the assertion
   value.

The LDAP definition for the integerOrderingMatch matching rule is:

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( 2.5.13.15 NAME 'integerOrderingMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.27 )

The integerOrderingMatch rule is an ordering matching rule.

4.2.21.  keywordMatch

The keywordMatch rule compares an assertion value of the Directory
   String syntax to an attribute value of a syntax (e.g., the Directory
   String syntax) whose corresponding ASN.1 type is DirectoryString.

The rule evaluates to TRUE if and only if the assertion value
   character string matches any keyword in the attribute value.  The
   identification of keywords in the attribute value and the exactness
   of the match are both implementation specific.

The LDAP definition for the keywordMatch rule is:

( 2.5.13.33 NAME 'keywordMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )

4.2.22.  numericStringMatch

The numericStringMatch rule compares an assertion value of the
   Numeric String syntax to an attribute value of a syntax (e.g., the
   Numeric String syntax) whose corresponding ASN.1 type is
   NumericString.

In preparing the attribute value and assertion value for comparison,
   characters are not case folded in the Map preparation step, and only
   numericString Insignificant Character Handling is applied in the
   Insignificant Character Handling step.

The LDAP definition for the numericStringMatch matching rule is:

( 2.5.13.8 NAME 'numericStringMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.36 )

The numericStringMatch rule is an equality matching rule.

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4.2.23.  numericStringOrderingMatch

The numericStringOrderingMatch rule compares an assertion value of
   the Numeric String syntax to an attribute value of a syntax (e.g.,
   the Numeric String syntax) whose corresponding ASN.1 type is
   NumericString.

The rule is identical to the caseIgnoreOrderingMatch rule except that
   all space characters are skipped during comparison (case is
   irrelevant as the characters are numeric).

The LDAP definition for the numericStringOrderingMatch matching rule
   is:

( 2.5.13.9 NAME 'numericStringOrderingMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.36 )

The numericStringOrderingMatch rule is an ordering matching rule.

4.2.24.  numericStringSubstringsMatch

The numericStringSubstringsMatch rule compares an assertion value of
   the Substring Assertion syntax to an attribute value of a syntax
   (e.g., the Numeric String syntax) whose corresponding ASN.1 type is
   NumericString.

In preparing the attribute value and assertion value for comparison,
   characters are not case folded in the Map preparation step, and only

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numericString Insignificant Character Handling is applied in the
   Insignificant Character Handling step.

The LDAP definition for the numericStringSubstringsMatch matching
   rule is:

( 2.5.13.10 NAME 'numericStringSubstringsMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )

The numericStringSubstringsMatch rule is a substrings matching rule.

4.2.25.  objectIdentifierFirstComponentMatch

The objectIdentifierFirstComponentMatch rule compares an assertion
   value of the OID syntax to an attribute value of a syntax (e.g., the
   Attribute Type Description, DIT Content Rule Description, LDAP Syntax
   Description, Matching Rule Description, Matching Rule Use
   Description, Name Form Description, or Object Class Description
   syntax) whose corresponding ASN.1 type is a SEQUENCE with a mandatory
   first component of the OBJECT IDENTIFIER ASN.1 type.

Note that the assertion syntax of this matching rule differs from the
   attribute syntax of attributes for which this is the equality
   matching rule.

The rule evaluates to TRUE if and only if the assertion value matches
   the first component of the attribute value using the rules of
   objectIdentifierMatch.

The LDAP definition for the objectIdentifierFirstComponentMatch
   matching rule is:

( 2.5.13.30 NAME 'objectIdentifierFirstComponentMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 )

The objectIdentifierFirstComponentMatch rule is an equality matching
   rule.  When using objectIdentifierFirstComponentMatch to compare two
   attribute values (of an applicable syntax), an assertion value must
   first be derived from one of the attribute values.  An assertion
   value can be derived from an attribute value by taking the first
   component of that attribute value.

4.2.26.  objectIdentifierMatch

The objectIdentifierMatch rule compares an assertion value of the OID
   syntax to an attribute value of a syntax (e.g., the OID syntax) whose
   corresponding ASN.1 type is OBJECT IDENTIFIER.

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The rule evaluates to TRUE if and only if the assertion value and the
   attribute value represent the same object identifier; that is, the
   same sequence of integers, whether represented explicitly in the
   <numericoid> form of <oid> or implicitly in the <descr> form (see
   [RFC4512]).

If an LDAP client supplies an assertion value in the <descr> form and
   the chosen descriptor is not recognized by the server, then the
   objectIdentifierMatch rule evaluates to Undefined.

The LDAP definition for the objectIdentifierMatch matching rule is:

( 2.5.13.0 NAME 'objectIdentifierMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.38 )

The objectIdentifierMatch rule is an equality matching rule.

4.2.27.  octetStringMatch

The octetStringMatch rule compares an assertion value of the Octet
   String syntax to an attribute value of a syntax (e.g., the Octet
   String or JPEG syntax) whose corresponding ASN.1 type is the OCTET
   STRING ASN.1 type.

The rule evaluates to TRUE if and only if the attribute value and the
   assertion value are the same length and corresponding octets (by
   position) are the same.

The LDAP definition for the octetStringMatch matching rule is:

( 2.5.13.17 NAME 'octetStringMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.40 )

The octetStringMatch rule is an equality matching rule.

4.2.28.  octetStringOrderingMatch

The octetStringOrderingMatch rule compares an assertion value of the
   Octet String syntax to an attribute value of a syntax (e.g., the
   Octet String or JPEG syntax) whose corresponding ASN.1 type is the
   OCTET STRING ASN.1 type.

The rule evaluates to TRUE if and only if the attribute value appears
   earlier in the collation order than the assertion value.  The rule
   compares octet strings from the first octet to the last octet, and
   from the most significant bit to the least significant bit within the
   octet.  The first occurrence of a different bit determines the
   ordering of the strings.  A zero bit precedes a one bit.  If the

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strings contain different numbers of octets but the longer string is
   identical to the shorter string up to the length of the shorter
   string, then the shorter string precedes the longer string.

The LDAP definition for the octetStringOrderingMatch matching rule
   is:

( 2.5.13.18 NAME 'octetStringOrderingMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.40 )

The octetStringOrderingMatch rule is an ordering matching rule.

4.2.29.  telephoneNumberMatch

The telephoneNumberMatch rule compares an assertion value of the
   Telephone Number syntax to an attribute value of a syntax (e.g., the
   Telephone Number syntax) whose corresponding ASN.1 type is a
   PrintableString representing a telephone number.

In preparing the attribute value and assertion value for comparison,
   characters are case folded in the Map preparation step, and only
   telephoneNumber Insignificant Character Handling is applied in the
   Insignificant Character Handling step.

The LDAP definition for the telephoneNumberMatch matching rule is:

( 2.5.13.20 NAME 'telephoneNumberMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.50 )

The telephoneNumberMatch rule is an equality matching rule.

4.2.30.  telephoneNumberSubstringsMatch

The telephoneNumberSubstringsMatch rule compares an assertion value
   of the Substring Assertion syntax to an attribute value of a syntax
   (e.g., the Telephone Number syntax) whose corresponding ASN.1 type is
   a PrintableString representing a telephone number.

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(3) a <final> substring, if present, matches the end of the prepared
   attribute value character string.  A prepared substring matches a
   portion of the prepared attribute value character string if
   corresponding characters have the same code point.

In preparing the attribute value and assertion value substrings for
   comparison, characters are case folded in the Map preparation step,
   and only telephoneNumber Insignificant Character Handling is applied
   in the Insignificant Character Handling step.

The LDAP definition for the telephoneNumberSubstringsMatch matching
   rule is:

( 2.5.13.21 NAME 'telephoneNumberSubstringsMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.58 )

The telephoneNumberSubstringsMatch rule is a substrings matching
   rule.

4.2.31.  uniqueMemberMatch

The uniqueMemberMatch rule compares an assertion value of the Name
   And Optional UID syntax to an attribute value of a syntax (e.g., the
   Name And Optional UID syntax) whose corresponding ASN.1 type is
   NameAndOptionalUID.

The rule evaluates to TRUE if and only if the <distinguishedName>
   components of the assertion value and attribute value match according
   to the distinguishedNameMatch rule and either, (1) the <BitString>
   component is absent from both the attribute value and assertion
   value, or (2) the <BitString> component is present in both the
   attribute value and the assertion value and the <BitString> component
   of the assertion value matches the <BitString> component of the
   attribute value according to the bitStringMatch rule.

Note that this matching rule has been altered from its description in
   X.520 [X.520] in order to make the matching rule commutative.  Server
   implementors should consider using the original X.520 semantics
   (where the matching was less exact) for approximate matching of
   attributes with uniqueMemberMatch as the equality matching rule.

The LDAP definition for the uniqueMemberMatch matching rule is:

( 2.5.13.23 NAME 'uniqueMemberMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.34 )

The uniqueMemberMatch rule is an equality matching rule.

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4.2.32.  wordMatch

The wordMatch rule compares an assertion value of the Directory
   String syntax to an attribute value of a syntax (e.g., the Directory
   String syntax) whose corresponding ASN.1 type is DirectoryString.

The rule evaluates to TRUE if and only if the assertion value word
   matches, according to the semantics of caseIgnoreMatch, any word in
   the attribute value.  The precise definition of a word is
   implementation specific.

The LDAP definition for the wordMatch rule is:

( 2.5.13.32 NAME 'wordMatch'
         SYNTAX 1.3.6.1.4.1.1466.115.121.1.15 )

5.  Security Considerations

In general, the LDAP-specific encodings for syntaxes defined in this
   document do not define canonical encodings.  That is, a
   transformation from an LDAP-specific encoding into some other
   encoding (e.g., BER) and back into the LDAP-specific encoding will
   not necessarily reproduce exactly the original octets of the LDAP-
   specific encoding.  Therefore, an LDAP-specific encoding should not
   be used where a canonical encoding is required.

Furthermore, the LDAP-specific encodings do not necessarily enable an
   alternative encoding of values of the Directory String and DN
   syntaxes to be reconstructed; e.g., a transformation from a
   Distinguished Encoding Rules (DER) [BER] encoding to an LDAP-specific
   encoding and back to a DER encoding may not reproduce the original
   DER encoding.  Therefore, LDAP-specific encodings should not be used
   where reversibility to DER is needed; e.g., for the verification of
   digital signatures.  Instead, DER or a DER-reversible encoding should
   be used.

When interpreting security-sensitive fields (in particular, fields
   used to grant or deny access), implementations MUST ensure that any
   matching rule comparisons are done on the underlying abstract value,
   regardless of the particular encoding used.

6.  Acknowledgements

This document is primarily a revision of RFC 2252 by M. Wahl, A.
   Coulbeck, T. Howes, and S. Kille.  RFC 2252 was a product of the IETF
   ASID Working Group.

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This document is based on input from the IETF LDAPBIS working group.
   The author would like to thank Kathy Dally for editing the early
   drafts of this document, and Jim Sermersheim and Kurt Zeilenga for
   their significant contributions to this revision.

7.  IANA Considerations

The Internet Assigned Numbers Authority (IANA) has updated the LDAP
   descriptors registry [BCP64] as indicated by the following templates:

Subject: Request for LDAP Descriptor Registration Update
      Descriptor (short name): see comment
      Object Identifier: see comment
      Person & email address to contact for further information:
        Steven Legg <steven.legg@eb2bcom.com>
      Usage: see comment
      Specification: RFC 4517
      Author/Change Controller: IESG

NAME                              Type  OID
      ------------------------------------------------------------------
      bitStringMatch                       M  2.5.13.16
      booleanMatch                         M  2.5.13.13
      caseExactIA5Match                    M  1.3.6.1.4.1.1466.109.114.1
      caseExactMatch                       M  2.5.13.5
      caseExactOrderingMatch               M  2.5.13.6
      caseExactSubstringsMatch             M  2.5.13.7
      caseIgnoreIA5Match                   M  1.3.6.1.4.1.1466.109.114.2
      caseIgnoreListMatch                  M  2.5.13.11
      caseIgnoreListSubstringsMatch        M  2.5.13.12
      caseIgnoreMatch                      M  2.5.13.2
      caseIgnoreOrderingMatch              M  2.5.13.3
      caseIgnoreSubstringsMatch            M  2.5.13.4
      directoryStringFirstComponentMatch   M  2.5.13.31
      distinguishedNameMatch               M  2.5.13.1
      generalizedTimeMatch                 M  2.5.13.27
      generalizedTimeOrderingMatch         M  2.5.13.28
      integerFirstComponentMatch           M  2.5.13.29
      integerMatch                         M  2.5.13.14
      integerOrderingMatch                 M  2.5.13.15
      keywordMatch                         M  2.5.13.33
      numericStringMatch                   M  2.5.13.8
      numericStringOrderingMatch           M  2.5.13.9
      numericStringSubstringsMatch         M  2.5.13.10
      objectIdentifierFirstComponentMatch  M  2.5.13.30
      octetStringMatch                     M  2.5.13.17
      octetStringOrderingMatch             M  2.5.13.18
      telephoneNumberMatch                 M  2.5.13.20

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telephoneNumberSubstringsMatch       M  2.5.13.21
      uniqueMemberMatch                    M  2.5.13.23
      wordMatch                            M  2.5.13.32

The descriptor for the object identifier 2.5.13.0 was incorrectly
      registered as objectIdentifiersMatch (extraneous \`s') in BCP 64.
      It has been changed to the following, with a reference to
      RFC 4517.

NAME                              Type  OID
      ------------------------------------------------------------------
      objectIdentifierMatch                M  2.5.13.0

Subject: Request for LDAP Descriptor Registration
      Descriptor (short name): caseIgnoreIA5SubstringsMatch
      Object Identifier: 1.3.6.1.4.1.1466.109.114.3
      Person & email address to contact for further information:
        Steven Legg <steven.legg@eb2bcom.com>
      Usage: other (M)
      Specification: RFC 4517
      Author/Change Controller: IESG

8.  References

8.1.  Normative References

[RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

[RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, November 2003.

[RFC4234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", RFC 4234, October 2005.

[RFC4510]  Zeilenga, K., Ed., "Lightweight Directory Access Protocol
              (LDAP): Technical Specification Road Map", RFC 4510, June
              2006.

[RFC4511]  Sermersheim, J., Ed., "Lightweight Directory Access
              Protocol (LDAP): The Protocol", RFC 4511, June 2006.

[RFC4512]  Zeilenga, K., "Lightweight Directory Access Protocol
              (LDAP): Directory Information Models", RFC 4512, June
              2006.

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RFC 4517           LDAP: Syntaxes and Matching Rules           June 2006

[RFC4514]  Zeilenga, K., Ed., "Lightweight Directory Access Protocol
              (LDAP): String Representation of Distinguished Names", RFC
              4514, June 2006.

[RFC4518]  Zeilenga, K., "Lightweight Directory Access Protocol
              (LDAP): Internationalized String Preparation", RFC 4518,
              June 2006.

[RFC4520]  Zeilenga, K., "Internet Assigned Numbers Authority (IANA)
              Considerations for the Lightweight Directory Access
              Protocol (LDAP)", BCP 64, RFC 4520, June 2006.

[E.123]    Notation for national and international telephone numbers,
              ITU-T Recommendation E.123, 1988.

[FAX]      Standardization of Group 3 facsimile apparatus for
              document transmission - Terminal Equipment and Protocols
              for Telematic Services, ITU-T Recommendation T.4, 1993

[T.50]     International Reference Alphabet (IRA) (Formerly
              International Alphabet No. 5 or IA5) Information
              Technology - 7-Bit Coded Character Set for Information
              Interchange, ITU-T Recommendation T.50, 1992

[X.420]    ITU-T Recommendation X.420 (1996) | ISO/IEC 10021-7:1997,
              Information Technology - Message Handling Systems (MHS):
              Interpersonal messaging system

[X.501]    ITU-T Recommendation X.501 (1993) | ISO/IEC 9594-2:1994,
              Information Technology - Open Systems Interconnection -
              The Directory: Models

[X.520]    ITU-T Recommendation X.520 (1993) | ISO/IEC 9594-6:1994,
              Information Technology - Open Systems Interconnection -
              The Directory: Selected attribute types

[ASN.1]    ITU-T Recommendation X.680 (07/02) | ISO/IEC 8824-1:2002,
              Information technology - Abstract Syntax Notation One
              (ASN.1): Specification of basic notation

[ISO3166]  ISO 3166, "Codes for the representation of names of
              countries".

[ISO8601]  ISO 8601:2004, "Data elements and interchange formats --
              Information interchange -- Representation of dates and
              times".

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RFC 4517           LDAP: Syntaxes and Matching Rules           June 2006

[UCS]      Universal Multiple-Octet Coded Character Set (UCS) -
              Architecture and Basic Multilingual Plane, ISO/IEC 10646-
              1:  1993 (with amendments).

[JPEG]     JPEG File Interchange Format (Version 1.02).  Eric
              Hamilton, C-Cube Microsystems, Milpitas, CA, September 1,
              1992.

8.2.  Informative References

[RFC4519]  Sciberras, A., Ed., "Lightweight Directory Access Protocol
              (LDAP): Schema for User Applications", RFC 4519, June
              2006.

[RFC4523]  Zeilenga, K., "Lightweight Directory Access Protocol
              (LDAP) Schema Definitions for X.509 Certificates", RFC
              4523, June 2006.

[X.500]    ITU-T Recommendation X.500 (1993) | ISO/IEC 9594-1:1994,
              Information Technology - Open Systems Interconnection -
              The Directory: Overview of concepts, models and services

[BER]      ITU-T Recommendation X.690 (07/02) | ISO/IEC 8825-1:2002,
              Information technology - ASN.1 encoding rules:
              Specification of Basic Encoding Rules (BER), Canonical
              Encoding Rules (CER) and Distinguished Encoding Rules
              (DER)

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Appendix A. Summary of Syntax Object Identifiers

The following list summarizes the object identifiers assigned to the
   syntaxes defined in this document.

Syntax                           OBJECT IDENTIFIER
      ==============================================================
      Attribute Type Description       1.3.6.1.4.1.1466.115.121.1.3
      Bit String                       1.3.6.1.4.1.1466.115.121.1.6
      Boolean                          1.3.6.1.4.1.1466.115.121.1.7
      Country String                   1.3.6.1.4.1.1466.115.121.1.11
      Delivery Method                  1.3.6.1.4.1.1466.115.121.1.14
      Directory String                 1.3.6.1.4.1.1466.115.121.1.15
      DIT Content Rule Description     1.3.6.1.4.1.1466.115.121.1.16
      DIT Structure Rule Description   1.3.6.1.4.1.1466.115.121.1.17
      DN                               1.3.6.1.4.1.1466.115.121.1.12
      Enhanced Guide                   1.3.6.1.4.1.1466.115.121.1.21
      Facsimile Telephone Number       1.3.6.1.4.1.1466.115.121.1.22
      Fax                              1.3.6.1.4.1.1466.115.121.1.23
      Generalized Time                 1.3.6.1.4.1.1466.115.121.1.24
      Guide                            1.3.6.1.4.1.1466.115.121.1.25
      IA5 String                       1.3.6.1.4.1.1466.115.121.1.26
      Integer                          1.3.6.1.4.1.1466.115.121.1.27
      JPEG                             1.3.6.1.4.1.1466.115.121.1.28
      LDAP Syntax Description          1.3.6.1.4.1.1466.115.121.1.54
      Matching Rule Description        1.3.6.1.4.1.1466.115.121.1.30
      Matching Rule Use Description    1.3.6.1.4.1.1466.115.121.1.31
      Name And Optional UID            1.3.6.1.4.1.1466.115.121.1.34
      Name Form Description            1.3.6.1.4.1.1466.115.121.1.35
      Numeric String                   1.3.6.1.4.1.1466.115.121.1.36
      Object Class Description         1.3.6.1.4.1.1466.115.121.1.37
      Octet String                     1.3.6.1.4.1.1466.115.121.1.40
      OID                              1.3.6.1.4.1.1466.115.121.1.38
      Other Mailbox                    1.3.6.1.4.1.1466.115.121.1.39
      Postal Address                   1.3.6.1.4.1.1466.115.121.1.41
      Printable String                 1.3.6.1.4.1.1466.115.121.1.44
      Substring Assertion              1.3.6.1.4.1.1466.115.121.1.58
      Telephone Number                 1.3.6.1.4.1.1466.115.121.1.50
      Teletex Terminal Identifier      1.3.6.1.4.1.1466.115.121.1.51
      Telex Number                     1.3.6.1.4.1.1466.115.121.1.52
      UTC Time                         1.3.6.1.4.1.1466.115.121.1.53

Appendix B. Changes from RFC 2252

This annex lists the significant differences between this
   specification and RFC 2252.

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This annex is provided for informational purposes only.  It is not a
   normative part of this specification.

1.  The IESG Note has been removed.

2.  The major part of Sections 4, 5 and 7 has been moved to [RFC4512]
       and revised.  Changes to the parts of these sections moved to
       [RFC4512] are detailed in [RFC4512].

3.  BNF descriptions of syntax formats have been replaced by ABNF
       [RFC4234] specifications.

4.  The ambiguous statement in RFC 2252, Section 4.3 regarding the
       use of a backslash quoting mechanism to escape separator symbols
       has been removed.  The escaping mechanism is now explicitly
       represented in the ABNF for the syntaxes where this provision
       applies.

5.  The description of each of the LDAP syntaxes has been expanded so
       that they are less dependent on knowledge of X.500 for
       interpretation.

6.  The relationship of LDAP syntaxes to corresponding ASN.1 type
       definitions has been made explicit.

7.  The set of characters allowed in a <PrintableString> (formerly
       <printablestring>) has been corrected to align with the
       PrintableString ASN.1 type in [ASN.1].  Specifically, the double
       quote character has been removed and the single quote character
       and equals sign have been added.

8.  Values of the Directory String, Printable String and Telephone
       Number syntaxes are now required to have at least one character.

9.  The <DITContentRuleDescription>, <NameFormDescription> and
       <DITStructureRuleDescription> rules have been moved to [RFC4512].

10. The corresponding ASN.1 type for the Other Mailbox syntax has
       been incorporated from RFC 1274.

11. A corresponding ASN.1 type for the LDAP Syntax Description syntax
       has been invented.

12. The Binary syntax has been removed because it was not adequately
       specified, implementations with different incompatible
       interpretations exist, and it was confused with the ;binary
       transfer encoding.

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13. All discussion of transfer options, including the ";binary"
       option, has been removed.  All imperatives regarding binary
       transfer of values have been removed.

14. The Delivery Method, Enhanced Guide, Guide, Octet String, Teletex
       Terminal Identifier and Telex Number syntaxes from RFC 2256 have
       been incorporated.

15. The <criteria> rule for the Enhanced Guide and Guide syntaxes has
       been extended to accommodate empty "and" and "or" expressions.

16. An encoding for the <ttx-value> rule in the Teletex Terminal
       Identifier syntax has been defined.

17. The PKI-related syntaxes (Certificate, Certificate List and
       Certificate Pair) have been removed.  They are reintroduced in
       [RFC4523] (as is the Supported Algorithm syntax from RFC 2256).

18. The MHS OR Address syntax has been removed since its
       specification (in RFC 2156) is not at draft standard maturity.

19. The DL Submit Permission syntax has been removed as it depends on
       the MHS OR Address syntax.

20. The Presentation Address syntax has been removed since its
       specification (in RFC 1278) is not at draft standard maturity.

21. The ACI Item, Access Point, Audio, Data Quality, DSA Quality, DSE
       Type, LDAP Schema Description, Master And Shadow Access Points,
       Modify Rights, Protocol Information, Subtree Specification,
       Supplier Information, Supplier Or Consumer and Supplier And
       Consumer syntaxes have been removed.  These syntaxes are
       referenced in RFC 2252, but not defined.

22. The LDAP Schema Definition syntax (defined in RFC 2927) and the
       Mail Preference syntax have been removed on the grounds that they
       are out of scope for the core specification.

23. The description of each of the matching rules has been expanded
       so that they are less dependent on knowledge of X.500 for
       interpretation.

24. The caseIgnoreIA5SubstringsMatch matching rule from RFC 2798 has
       been added.

25. The caseIgnoreListSubstringsMatch, caseIgnoreOrderingMatch and
       caseIgnoreSubstringsMatch matching rules have been added to the
       list of matching rules for which the provisions for handling

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leading, trailing and multiple adjoining whitespace characters
       apply (now through string preparation).  This is consistent with
       the definitions of these matching rules in X.500.  The
       caseIgnoreIA5SubstringsMatch rule has also been added to the
       list.

26. The specification of the octetStringMatch matching rule from
       RFC 2256 has been added to this document.

27. The presentationAddressMatch matching rule has been removed as it
       depends on an assertion syntax (Presentation Address) that is not
       at draft standard maturity.

28. The protocolInformationMatch matching rule has been removed as it
       depends on an undefined assertion syntax (Protocol Information).

29. The definitive reference for ASN.1 has been changed from X.208 to
       X.680 since X.680 is the version of ASN.1 referred to by X.500.

30. The specification of the caseIgnoreListSubstringsMatch matching
       rule from RFC 2798 & X.520 has been added.

31. String preparation algorithms have been applied to the character
       string matching rules.

32. The specifications of the booleanMatch, caseExactMatch,
       caseExactOrderingMatch, caseExactSubstringsMatch,
       directoryStringFirstComponentMatch, integerOrderingMatch,
       keywordMatch, numericStringOrderingMatch,
       octetStringOrderingMatch and wordMatch matching rules from
       RFC 3698 & X.520 have been added.

Author's Address

Steven Legg
   eB2Bcom
   Suite3, Woodhouse Corporate Centre
   935 Station Street
   Box Hill North, Victoria 3129
   AUSTRALIA

Phone: +61 3 9896 7830
   Fax: +61 3 9896 7801
   EMail: steven.legg@eb2bcom.com

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Full Copyright Statement

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   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

This document and the information contained herein are provided on an
   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
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   INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
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Acknowledgement

Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).

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