PRECIS Framework: Preparation and Comparison of Internationalized Strings in Application Protocols
draft-ietf-precis-framework-07
PRECIS P. Saint-Andre
Internet-Draft Cisco Systems, Inc.
Obsoletes: 3454 (if approved) M. Blanchet
Intended status: Standards Track Viagenie
Expires: September 27, 2013 March 26, 2013
PRECIS Framework: Preparation and Comparison of Internationalized
Strings in Application Protocols
draft-ietf-precis-framework-07
Abstract
Application protocols using Unicode code points in protocol strings
need to properly prepare such strings in order to perform valid
comparison operations (e.g., for purposes of authentication or
authorization). This document defines a framework enabling
application protocols to perform the preparation and comparison of
internationalized strings (a.k.a. "PRECIS") in a way that depends on
the properties of Unicode code points and thus is agile with respect
to versions of Unicode. As a result, this framework provides a more
sustainable approach to the handling of internationalized strings
than the previous framework, known as Stringprep (RFC 3454). A
specification that reuses this framework can either directly use the
PRECIS string classes or subclass the PRECIS string classes as
needed. This framework takes an approach similar to the revised
internationalized domain names (IDNs) in applications (IDNA)
technology (RFC 5890, RFC 5891, RFC 5892, RFC 5893, RFC 5894) and
thus adheres to the high-level design goals described in the IAB's
recommendations regarding IDNs (RFC 4690), albeit for application
technologies other than the Domain Name System (DNS). This document
obsoletes RFC 3454.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
Saint-Andre & Blanchet Expires September 27, 2013 [Page 1]
Internet-Draft PRECIS Framework March 2013
This Internet-Draft will expire on September 27, 2013.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. String Classes . . . . . . . . . . . . . . . . . . . . . . . 5
3.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 5
3.2. IdentifierClass . . . . . . . . . . . . . . . . . . . . . 7
3.3. FreeformClass . . . . . . . . . . . . . . . . . . . . . . 9
4. Use of PRECIS String Classes . . . . . . . . . . . . . . . . 11
4.1. Principles . . . . . . . . . . . . . . . . . . . . . . . 11
4.2. Subclassing . . . . . . . . . . . . . . . . . . . . . . . 11
4.3. Building Application-Layer Constructs . . . . . . . . . . 12
4.4. A Note about Spaces . . . . . . . . . . . . . . . . . . . 13
5. Code Point Properties . . . . . . . . . . . . . . . . . . . . 13
6. Category Definitions Used to Calculate Derived Property Value 15
6.1. LetterDigits (A) . . . . . . . . . . . . . . . . . . . . 16
6.2. Unstable (B) . . . . . . . . . . . . . . . . . . . . . . 16
6.3. IgnorableProperties (C) . . . . . . . . . . . . . . . . . 16
6.4. IgnorableBlocks (D) . . . . . . . . . . . . . . . . . . . 17
6.5. LDH (E) . . . . . . . . . . . . . . . . . . . . . . . . . 17
6.6. Exceptions (F) . . . . . . . . . . . . . . . . . . . . . 17
6.7. BackwardCompatible (G) . . . . . . . . . . . . . . . . . 18
6.8. JoinControl (H) . . . . . . . . . . . . . . . . . . . . . 19
6.9. OldHangulJamo (I) . . . . . . . . . . . . . . . . . . . . 19
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