Common Elements of Generic String Encoding Rules (GSER) Encodings
RFC 3642
Document | Type |
RFC - Informational
(October 2003; Errata)
Was draft-legg-ldap-gser-abnf (individual in app area)
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Author | Steven Legg | ||
Last updated | 2020-01-21 | ||
Stream | IETF | ||
Formats | plain text html pdf htmlized with errata bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 3642 (Informational) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Ted Hardie | ||
IESG note |
New versions exists which is verified with IESG Responsible: Patrik |
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Send notices to | <kurt@openLDAP.org> |
Network Working Group S. Legg Request for Comments: 3642 Adacel Technologies Category: Informational October 2003 Common Elements of Generic String Encoding Rules (GSER) Encodings Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract The Generic String Encoding Rules (GSER) describe a human readable text encoding for an Abstract Syntax Notation One (ASN.1) value of any ASN.1 type. Specifications making use of GSER may wish to provide an equivalent Augmented Backus-Naur Form (ABNF) description of the GSER encoding for a particular ASN.1 type as a convenience for implementors. This document supports such specifications by providing equivalent ABNF for the GSER encodings for ASN.1 types that commonly occur in Lightweight Directory Access Protocol (LDAP) syntaxes. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Conventions. . . . . . . . . . . . . . . . . . . . . . . . . . 2 3. Separators . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4. ASN.1 Built-in Types . . . . . . . . . . . . . . . . . . . . . 2 5. ASN.1 Restricted String Types. . . . . . . . . . . . . . . . . 7 6. Directory ASN.1 Types. . . . . . . . . . . . . . . . . . . . . 9 7. Security Considerations. . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . 10 8.2. Informative References . . . . . . . . . . . . . . . . . 11 9. Intellectual Property Notice . . . . . . . . . . . . . . . . . 12 10. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 12 11. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 13 Legg Informational [Page 1] RFC 3642 Common Elements of GSER Encodings October 2003 1. Introduction The Generic String Encoding Rules (GSER) [7] define a human readable text encoding, based on ASN.1 [8] value notation, for an ASN.1 value of any ASN.1 type. Specifications making use of GSER may wish to provide a non-normative equivalent ABNF [3] description of the GSER encoding for a particular ASN.1 type as a convenience for implementors unfamiliar with ASN.1. This document supports such specifications by providing equivalent ABNF for the GSER encodings for ASN.1 types that commonly occur in LDAP [10] or X.500 [11] attribute and assertion syntaxes, as well as equivalent ABNF for the GSER encodings for the ASN.1 built-in types. The ABNF given in this document does not replace or alter GSER in any way. If there is a discrepancy between the ABNF specified here and the encoding defined by GSER [7], then GSER is to be taken as definitive. 2. Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", and "MAY" in this document are to be interpreted as described in BCP 14, RFC 2119 [1]. The key word "OPTIONAL" is exclusively used with its ASN.1 meaning. 3. Separators Certain separators are commonly used in constructing equivalent ABNF for SET and SEQUENCE types. sp = *%x20 ; zero, one or more space characters msp = 1*%x20 ; one or more space characters sep = [ "," ] The <sep> rule is used in the ABNF description of the encoding for ASN.1 SET or SEQUENCE types where all the components are either OPTIONAL or DEFAULT. It encodes to an empty string if and only if the immediately preceding character in the encoding is "{", i.e., it is only empty for the first optional component actually present in the SET or SEQUENCE value being encoded. 4. ASN.1 Built-in Types This section describes the GSER encoding of values of the ASN.1 built-in types, except for the restricted character string types. Legg Informational [Page 2] RFC 3642 Common Elements of GSER Encodings October 2003 The <BIT-STRING> rule describes the GSER encoding of values of the BIT STRING type without a named bit list. BIT-STRING = bstring / hstring If the number of bits in a BIT STRING value is a multiple of four the <hstring> form of <BIT-STRING> MAY be used. Otherwise, the <bstring> form of <BIT-STRING> is used. The <bstring> rule encodes each bit as the character "0" or "1" in order from the first bit to the last bit. The <hstring> rule encodes each group of four bits as a hexadecimal number where the first bit is the most significant. An odd number ofShow full document text