PRECIS Framework: Preparation, Enforcement, and Comparison of Internationalized Strings in Application Protocols
RFC 8264
| Document | Type |
RFC - Proposed Standard
(October 2017; Errata)
Obsoletes RFC 7564
|
|
|---|---|---|---|
| Last updated | 2018-08-27 | ||
| Stream | IETF | ||
| Formats | plain text pdf html bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Marc Blanchet | ||
| Shepherd write-up | Show (last changed 2017-05-30) | ||
| IESG | IESG state | RFC 8264 (Proposed Standard) | |
| Consensus Boilerplate | Yes | ||
| Telechat date | |||
| Responsible AD | Alexey Melnikov | ||
| Send notices to | Marc Blanchet <Marc.Blanchet@viagenie.ca> | ||
| IANA | IANA review state | Version Changed - Review Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) P. Saint-Andre
Request for Comments: 8264 Jabber.org
Obsoletes: 7564 M. Blanchet
Category: Standards Track Viagenie
ISSN: 2070-1721 October 2017
PRECIS Framework: Preparation, Enforcement, and Comparison of
Internationalized Strings in Application Protocols
Abstract
Application protocols using Unicode code points in protocol strings
need to properly handle such strings in order to enforce
internationalization rules for strings placed in various protocol
slots (such as addresses and identifiers) and 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, enforcement, and
comparison of internationalized strings ("PRECIS") in a way that
depends on the properties of Unicode code points and thus is more
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). This document obsoletes RFC 7564.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc8264.
Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
Saint-Andre & Blanchet Standards Track [Page 1]
RFC 8264 PRECIS Framework October 2017
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Preparation, Enforcement, and Comparison . . . . . . . . . . 6
4. String Classes . . . . . . . . . . . . . . . . . . . . . . . 8
4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 8
4.2. IdentifierClass . . . . . . . . . . . . . . . . . . . . . 9
4.2.1. Valid . . . . . . . . . . . . . . . . . . . . . . . . 9
4.2.2. Contextual Rule Required . . . . . . . . . . . . . . 10
4.2.3. Disallowed . . . . . . . . . . . . . . . . . . . . . 10
4.2.4. Unassigned . . . . . . . . . . . . . . . . . . . . . 10
4.2.5. Examples . . . . . . . . . . . . . . . . . . . . . . 11
4.3. FreeformClass . . . . . . . . . . . . . . . . . . . . . . 11
4.3.1. Valid . . . . . . . . . . . . . . . . . . . . . . . . 11
4.3.2. Contextual Rule Required . . . . . . . . . . . . . . 12
4.3.3. Disallowed . . . . . . . . . . . . . . . . . . . . . 12
4.3.4. Unassigned . . . . . . . . . . . . . . . . . . . . . 12
4.3.5. Examples . . . . . . . . . . . . . . . . . . . . . . 12
4.4. Summary . . . . . . . . . . . . . . . . . . . . . . . . . 12
5. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1. Profiles Must Not Be Multiplied beyond Necessity . . . . 14
5.2. Rules . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2.1. Width Mapping Rule . . . . . . . . . . . . . . . . . 15
5.2.2. Additional Mapping Rule . . . . . . . . . . . . . . . 15
5.2.3. Case Mapping Rule . . . . . . . . . . . . . . . . . . 16
5.2.4. Normalization Rule . . . . . . . . . . . . . . . . . 16
5.2.5. Directionality Rule . . . . . . . . . . . . . . . . . 17
5.3. A Note about Spaces . . . . . . . . . . . . . . . . . . . 18
6. Applications . . . . . . . . . . . . . . . . . . . . . . . . 18
6.1. How to Use PRECIS in Applications . . . . . . . . . . . . 18
6.2. Further Excluded Characters . . . . . . . . . . . . . . . 20
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