RFC 3641 (rfc3641) - Page 2 of 16
Generic String Encoding Rules (GSER) for ASN
Alternative Format: Original Text Document
RFC 3641 Generic String Encoding Rules October 2003 3.18. INSTANCE OF. . . . . . . . . . . . . . . . . . . . . . . 11 3.19. REAL . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.20. Variant Encodings. . . . . . . . . . . . . . . . . . . . 12 4. GSER Transfer Syntax . . . . . . . . . . . . . . . . . . . . . 13 5. Security Considerations. . . . . . . . . . . . . . . . . . . . 13 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.1. Normative References . . . . . . . . . . . . . . . . . . 13 6.2. Informative References . . . . . . . . . . . . . . . . . 14 7. Intellectual Property Notice . . . . . . . . . . . . . . . . . 15 8. Author's Address . . . . . . . . . . . . . . . . . . . . . . . 15 9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 16 1. Introduction This document defines a set of ASN.1 [8] encoding rules, called the Generic String Encoding Rules or GSER, that produce a human readable UTF-8 [6] character string encoding of ASN.1 values of any given arbitrary ASN.1 type. Note that "ASN.1 value" does not mean a Basic Encoding Rules (BER) [12] encoded value. The ASN.1 value is an abstract concept that is independent of any particular encoding. BER is just one possible encoding of an ASN.1 value. GSER is based on ASN.1 value notation [8], with changes to accommodate the notation's use as a transfer syntax, and to support well established ad-hoc string encodings for Lightweight Directory Access Protocol (LDAP) [14] directory data types. Though primarily intended for defining the LDAP-specific encoding of new LDAP attribute syntaxes and assertion syntaxes, these encoding rules could also be used in other domains where human readable renderings of ASN.1 values would be useful. Referencing GSER is sufficient to define a human readable text encoding for values of a specific ASN.1 type, however other specifications may wish to provide a customized Augmented Backus-Naur Form (ABNF) [3] description, independent of the ASN.1, as a convenience for the implementor (equivalent ABNF for the GSER encodings for ASN.1 types commonly occurring in LDAP syntaxes is provided in a separate document [15]). Such a specification SHOULD state that if there is a discrepancy between the customized ABNF and the GSER encoding defined by this document, that the GSER encoding takes precedence. Legg Standards Track



