RFC 1778

RFC 1778 Network Working Group T. Howes Request for Comments: 1778 University of Michigan Obsoletes: RFC 1488 S. Kille Category: Standards Track ISODE Consortium W. Yeong Performance Systems International C. Robbins NeXor Ltd. March 1995 The String Representation of Standard Attribute Syntaxes 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 The Lightweight Directory Access Protocol (LDAP) [9] requires that the contents of AttributeValue fields in protocol elements be octet strings. This document defines the requirements that must be satisfied by encoding rules used to render X.500 Directory attribute syntaxes into a form suitable for use in the LDAP, then goes on to define the encoding rules for the standard set of attribute syntaxes defined in [1,2] and [3]. 1. Attribute Syntax Encoding Requirements. This section defines general requirements for lightweight directory protocol attribute syntax encodings. All documents defining attribute syntax encodings for use by the lightweight directory protocols are expected to conform to these requirements. The encoding rules defined for a given attribute syntax must produce octet strings. To the greatest extent possible, encoded octet strings should be usable in their native encoded form for display purposes. In particular, encoding rules for attribute syntaxes defining non-binary values should produce strings that can be displayed with little or no translation by clients implementing the lightweight directory protocols. Howes, Kille, Yeong & Robbins [Page 1] RFC 1778 Syntax Encoding March 1995 2. Standard Attribute Syntax Encodings For the purposes of defining the encoding rules for the standard attribute syntaxes, the following auxiliary BNF definitions will be used: ::= 'a' | 'b' | 'c' | 'd' | 'e' | 'f' | 'g' | 'h' | 'i' | 'j' | 'k' | 'l' | 'm' | 'n' | 'o' | 'p' | 'q' | 'r' | 's' | 't' | 'u' | 'v' | 'w' | 'x' | 'y' | 'z' | 'A' | 'B' | 'C' | 'D' | 'E' | 'F' | 'G' | 'H' | 'I' | 'J' | 'K' | 'L' | 'M' | 'N' | 'O' | 'P' | 'Q' | 'R' | 'S' | 'T' | 'U' | 'V' | 'W' | 'X' | 'Y' | 'Z' ::= '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' ::= | 'a' | 'b' | 'c' | 'd' | 'e' | 'f' | 'A' | 'B' | 'C' | 'D' | 'E' | 'F' ::= | | '-'

::= | | ''' | '(' | ')' | '+' | ',' | '-' | '.' | '/' | ':' | '?' | ' ' ::= The ASCII newline character with hexadecimal value 0x0A ::= | ::= | ::= | ::= | ::=

'#' |

::= ':' ::= ':'

= 'X400' = 'X500' where is as defined in RFC

1327. 2.35. Photo Values of type Photo are encoded as if they were octet strings containing JPEG images in the JPEG File Interchange Format (JFIF), as described in [8]. 2.36. Fax Values of type Fax are encoded as if they were octet strings containing Group 3 Fax images as defined in [7]. Howes, Kille, Yeong & Robbins [Page 10] RFC 1778 Syntax Encoding March 1995 3. Security Considerations Security issues are not discussed in this memo. 4. Acknowledgements Many of the attribute syntax encodings defined in this document are adapted from those used in the QUIPU X.500 implementation. The contributions of the authors of the QUIPU implementation in the specification of the QUIPU syntaxes [4] are gratefully acknowledged. 5. Bibliography [1] The Directory: Selected Attribute Syntaxes. CCITT, Recommendation X.520. [2] Information Processing Systems -- Open Systems Interconnection -- The Directory: Selected Attribute Syntaxes. [3] Barker, P., and S. Kille, "The COSINE and Internet X.500 Schema", RFC 1274, University College London, November 1991. [4] The ISO Development Environment: User's Manual -- Volume 5: QUIPU. Colin Robbins, Stephen E. Kille. [5] Kille, S., "A String Representation of Distinguished Names", RFC 1779, ISODE Consortium, March 1995. [6] Kille, S., "A String Representation for Presentation Addresses", RFC 1278, University College London, November 1991. [7] Terminal Equipment and Protocols for Telematic Services - Standardization of Group 3 facsimile apparatus for document transmission. CCITT, Recommendation T.4. [8] JPEG File Interchange Format (Version 1.02). Eric Hamilton, C- Cube Microsystems, Milpitas, CA, September 1, 1992. [9] Yeong, W., Howes, T., and S. Kille, "Lightweight Directory Access Protocol", RFC 1777, Performance Systems International, University of Michigan, ISODE Consortium, March 1995. [10] Alvestrand, H., Kille, S., Miles, R., Rose, M., and S. Thompson, "Mapping between X.400 and RFC-822 Message Bodies", RFC 1495, SINTEF DELAB, ISODE Consortium, Soft*Switch, Inc., Dover Beach Consulting, Inc., Soft*Switch, Inc., August 1993. Howes, Kille, Yeong & Robbins [Page 11] RFC 1778 Syntax Encoding March 1995 6. Authors' Addresses Tim Howes University of Michigan ITD Research Systems 535 W William St. Ann Arbor, MI 48103-4943 USA Phone: +1 313 747-4454 EMail: tim@umich.edu Steve Kille ISODE Consortium PO Box 505 London SW11 1DX UK Phone: +44-71-223-4062 EMail: S.Kille@isode.com Wengyik Yeong PSI Inc. 510 Huntmar Park Drive Herndon, VA 22070 USA Phone: +1 703-450-8001 EMail: yeongw@psilink.com Colin Robbins NeXor Ltd University Park Nottingham NG7 2RD UK Howes, Kille, Yeong & Robbins [Page 12]