As per Relevance of the word represent, we have this rfc below:
Network Working Group S.
Request for Comments: 1779 ISODE
Obsoletes: 1485 March 1995
Category: Standards
A String Representation of Distinguished
Status of this
This document specifies an Internet standards track protocol for
Internet community, and requests discussion and suggestions
improvements. Please refer to the current edition of the "
Official Protocol Standards" (STD 1) for the standardization
and status of this protocol. Distribution of this memo is unlimited
The OSI Directory uses distinguished names as the primary keys
entries in the directory. Distinguished Names are encoded in ASN.1.
When a distinguished name is communicated between to users not
a directory protocol (e.g., in a mail message), there is a need
have a user-oriented string representation of distinguished name
This specification defines a string format for representing names
which is designed to give a clean representation of commonly
names, whilst being able to represent any distinguished name
Table of
1. Why a notation is needed ................................... 2
2. A notation for Distinguished Name .......................... 2
2.1 Goals ................................................ 2
2.2 Informal definition .................................. 2
2.3 Formal definition .................................... 4
3. Examples ................................................... 6
4. Acknowledgements ........................................... 7
5. References ................................................. 7
6. Security Considerations .................................... 8
7. Author's Address ........................................... 8
Kille [Page 1]
RFC 1779 DN Representation March 1995
1. Why a notation is
Many OSI Applications make use of Distinguished Names (DN) as
in the OSI Directory, commonly known as X.500 [1].
specification assumes familiarity with X.500, and the concept
Distinguished Name. It is important to have a common format to
able to unambiguously represent a distinguished name. This might
done to represent a directory name on a business card or in an
message. There is a need for a format to support human to
communication, which must be string based (not ASN.1) and
oriented. This notation is targeted towards a general user
system, and in particular to represent the names of humans.
syntaxes may be more appropriate for other uses of the directory
For example, the OSF Syntax may be more appropriate for some
oriented uses. (The OSF Syntax uses "/" as a separator, and
names in a manner intended to resemble UNIX filenames).
2. A notation for Distinguished
2.1
The following goals are laid out
o To provide an unambiguous representation of a distinguished
o To be an intuitive format for the majority of
o To be fully general, and able to represent any distinguished
o To be amenable to a number of different layouts to achieve
attractive representation
o To give a clear representation of the contents of
distinguished
2.2 Informal
This notation is designed to be convenient for common forms of name
Some examples are given. The author's directory distinguished
would be written
CN=Steve Kille
O=ISODE Consortium, C=
Kille [Page 2]
RFC 1779 DN Representation March 1995
This may be folded, perhaps to display in multi-column format.
example
CN=Steve Kille
O=ISODE Consortium
C=
Another name might be
CN=Christian Huitema, O=INRIA, C=
Semicolon (";") may be used as an alternate separator.
separators may be mixed, but this usage is discouraged
CN=Christian Huitema; O=INRIA; C=
In running text, this would be written as
O=INRIA; C=FR>. Another example, shows how different attribute
are handled
CN=James Hacker
L=Basingstoke
O=Widget Inc
C=
Here is an example of a multi-valued Relative Distinguished Name
where the namespace is flat within an organisation, and department
used to disambiguate certain names
OU=Sales + CN=J. Smith, O=Widget Inc., C=
The final examples show both methods quoting of a comma in
Organisation name
CN=L. Eagle, O="Sue, Grabbit and Runn", C=
CN=L. Eagle, O=Sue\, Grabbit and Runn, C=
Kille [Page 3]
RFC 1779 DN Representation March 1995
2.3 Formal
A formal definition can now be given. The structure is specified
a BNF grammar in Figure 1. This BNF uses the grammar defined in
822, with the terminals enclosed in <> [2]. This definition is in
abstract character set, and so may be written in any character
supporting the explicitly defined special characters. The
mechanism is used for the following cases
o Strings containing ",", "+", "=" or """ , , "<",
">", "#", or ";".
o Strings with leading or trailing
o Strings containing consecutive
There is an escape mechanism from the normal user oriented form,
that this syntax may be used to print any valid distinguished name
This is ugly. It is expected to be used only in pathological cases
There are two parts to this mechanism
1. Attributes types are represented in a (big-endian)
notation. (e.g., OID.2.6.53).
2. Attribute values are represented in hexadecimal (e.g. #0A56CF).
Each pair of hex digits defines an octet, which is the ASN.1
Encoding Rules value of the Attribute Value
The keyword specification is optional in the BNF, but mandatory
this specification. This is so that the same BNF may be used for
related specification on User Friendly Naming [5]. When
specification is followed, the attribute type keywords must always
present
A list of valid keywords for well known attribute types used
naming is given in Table 1. Keywords may contain spaces, but
not have leading or trailing spaces. This is a list of
which must be supported. These are chosen because they appear
common forms of name, and can do so in a place which does
correspond to the default schema used. A register of valid
is maintained by the IANA
Kille [Page 4]
RFC 1779 DN Representation March 1995
::= component> ( )
| component>
::= <optional-space
<optional-space
::= "," | ";"
<optional-space> ::= ( ) *( " " )
component> ::= <attribute
| <attribute> <optional-space> "+"
<optional-space> component
<attribute> ::=
| <optional-space> "=" <optional-space>
::= 1*( ) | "OID." | "oid."
::= letters, numbers, and
::= | "."
::= 1*
::= digits 0-9
::= *( | )
| '"' *( | | ) '"'
| "#"
::= "," | "=" | | "+" | "<" | ">"
| "#" | ";"
::= "\" ( | "\" | '"')
::= any character except or "\" or '"'
::= 2*
::= 0-9, a-f, A-
Figure 1: BNF Grammar for Distinguished
Kille [Page 5]
RFC 1779 DN Representation March 1995
Key Attribute (X.520 keys
------------------------------
CN
L
ST
O
OU
C
STREET
Table 1: Standardised
Only string type attributes are considered, but other
syntaxes could be supported locally (e.g., by use of the
defined in [3].) It is assumed that the interface will
from the supplied string into an appropriate Directory
encoding. The "+" notation is used to specify multi-component RDNs
In this case, the types for attributes in the RDN must be explicit
The name is presented/input in a little-endian order (
significant component last). When an address is written in a
where there is a need to delimit the entire address (e.g., in
text), it is recommended that the delimiters <> are used.
terminator > is a special in the notation to facilitate
delimitation
3.
This section gives a few examples of distinguished names
using this notation
CN=Marshall T. Rose, O=Dover Beach Consulting, L=Santa Clara
ST=California, C=
CN=FTAM Service, CN=Bells, OU=Computer Science
O=University College London, C=
CN=Markus Kuhn, O=University of Erlangen, C=
CN=Steve Kille
O=ISODE Consortium
C=
Kille [Page 6]
RFC 1779 DN Representation March 1995
CN=Steve Kille ,
O = ISODE Consortium
C=
CN=Steve Kille, O=ISODE Consortium, C=
4.
This work was based on research work done at University
London [4], and evolved by the IETF OSI-DS WG
Input for this version of the document was received from:
Cargille (University of Wisconsin); John Dale (COS); Philip
(Onsett); John Hawthorne (US Air Force); Roland Hedberg (
of Umea); Kipp Hickman (Mosaic Communications Corp.) Markus
(University of Erlangen); Elisabeth Roudier (E3X); Mark Wahl (
Consortium).
5.
[1] The Directory --- overview of concepts, models and services
1993. CCITT X.500 Series Recommendations
[2] Crocker, D., "Standard of the Format of ARPA-Internet
Messages", STD 11, RFC 822, University of Delaware, August 1982.
[3] Yeong, W., Howes, T., and S. Kille, "Lightweight Directory
Protocol", RFC 1777, Performance Systems International
University of Michigan, ISODE Consortium, March 1995.
[4] S.E. Kille. Using the OSI directory to achieve user
naming. Research Note RN/20/29, Department of Computer Science
University College London, February 1990.
[5] Kille, S., "Using the OSI Directory to Achieve User
Naming", RFC 1781, ISODE Consortium, March 1995.
Kille [Page 7]
RFC 1779 DN Representation March 1995
6. Security
Security issues are not discussed in this memo
7. Author's
Steve
ISODE
The
The
Richmond,
TW9 1
Phone: +44-181-332-9091
EMail: S.Kille@ISODE.
DN: CN=Steve Kille
O=ISODE Consortium, C=
UFN: S. Kille
ISODE Consortium,
Kille [Page 8]
if you see any problems within the linking, don't worry be happy,
this is version 0.1 of the Relevance System and you gotta expect some crappy subroutines sometimes,
just be content we did not write this in Java, which would have made this "bigger and better" HAHAHHA.
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