Network Working Group T. Nemoto Internet-Draft D. Wang Intended status: Standards Track Keio University Expires: April 30, 2015 October 27, 2014 Preparation and Comparison of Customized Alternative Names draft-nemoto-precis-alternativenames-00 Abstract This document describes how to prepare and compare Unicode strings representing to customized alternative names for devices, which can be created and accessed by users definition, primarily as used within IoT environment like appliances controlling through home network. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. 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Nemoto & Wang Expires April 30, 2015 [Page 1] Internet-Draft precis mapping October 2014 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2. Differences from other PRECIS Profile . . . . . . . . . . 3 1.3. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 2. Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Security Considerations . . . . . . . . . . . . . . . . . . . 4 3.1. Reuse of PRECIS . . . . . . . . . . . . . . . . . . . . . 4 3.2. Reuse of Unicode . . . . . . . . . . . . . . . . . . . . 4 3.3. Visually Similar Characters . . . . . . . . . . . . . . . 4 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 5. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 5.1. Normative References . . . . . . . . . . . . . . . . . . 5 5.2. Informative References . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction 1.1. Overview In our daily life, users always using their mother language to create alternative names for devices (eg. PC or game machine), those alternative names will be different from the model number of those devices. Many users are naming their devices with such nicknames of internationalized strings. These strings have very high flexibility by using various of characters sets. For example, symbols like the Tilde mark ("WAVE DASH"(U+301C) it's not "FULLWIDTH TILDE"(U+FF5E)) in Japanese, which is used instead of the "KATAKANA-HIRAGANA PROLONGED SOUND MARK"(U+30FC), has being used as product names or part of adjective words in many kinds of fields. In the Internet environment especially for IoT devices, nicknames like this may be given to device or as part of the device name. To look up the devices by the names registered in database, it is necessary to take more appropriate and flexible preparation. So that it could be more compatible for any assumed character that provided by different input methods of applications. To increase the matching possibility that customized device alternative names described as above can be utilized correctly as internet resources, this document defines rules for preparing and comparing customized alternative names for devices, so that the accuracy of comparison result between alternative names strings could be improved. Nemoto & Wang Expires April 30, 2015 [Page 2] Internet-Draft precis mapping October 2014 1.2. Differences from other PRECIS Profile TBD. 1.3. Terminology Many important terms used in this document are defined in [I-D.ietf-precis-framework] and [Unicode]. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. 2. Rules A alternative name MUST NOT be zero bytes in length. This rule is to be enforced after any mapping or normalization of code points. A alternative name MUST consist only of Unicode code points that conform to the "FreeformClass" base string class defined in [I-D.ietf-precis-framework]. For preparation purposes, an application MUST only ensure that the string conforms to the "FreeformClass" base string class defined in [I-D.ietf-precis-framework]; however, it MAY also perform the mapping and normalization operations specified below for comparison. For comparison purposes, an application MUST treat a alternative name as follows, where the operations specified MUST be completed in the order shown: 1. Fullwidth and halfwidth characters MUST be mapped to their decomposition equivalents. 2. Additional mappings MAY be applied, such as those defined in [I-D.ietf-precis-framework] and [I-D.ietf-precis-mappings]. In the Additional Mappings, the rules of adapted Special Mapping are as below: 1. Non-ASCII space characters from the "N" category defined under Section 7.14 of [I-D.ietf-precis-framework] MUST be mapped to U+0020 SPACE. 2. Interior sequences of more than one ASCII space character MUST be mapped to a single ASCII space character. 3. Leading and trailing whitespace MUST be removed. Nemoto & Wang Expires April 30, 2015 [Page 3] Internet-Draft precis mapping October 2014 3. Uppercase and titlecase characters MUST be mapped to their lowercase equivalents using Unicode Default Case Folding. Local Case Mapping is applicable alternatively. 4. Unicode Normalization Form C (NFC) MUST be applied to all characters. With regard to directionality, the "Bidi Rule" provided in [RFC5893] applies. 3. Security Considerations 3.1. Reuse of PRECIS The security considerations described in [I-D.ietf-precis-framework] apply to the "FreeformClass" base string class used in this document for alternative names, respectively. 3.2. Reuse of Unicode The security considerations described in [UTR39] apply to the use of Unicode characters in alternative names. 3.3. Visually Similar Characters [[I-D.ietf-precis-framework] describes some of the security considerations related to visually similar characters, also called "confusable characters" or "confusables". Although the mapping rules under Section 2 are designed in part to reduce the possibility of confusion about alternative names, this document does not yet provide more detailed recommendations regarding the handling of visually similar characters, such as those in [UTR39]. However, a future version of this document might provide such recommendations. 4. IANA Considerations The IANA shall add the following entry to the PRECIS Profiles Registry: Name: Alternative Names FreeformClass. Applicability: TBD. Base Class: FreeformClass. Replaces: None. Width Mapping: Map fullwidth and halfwidth characters to their decomposition mappings. Additional Mappings: Map non-ASCII space characters to ASCII space, map interior sequences of multiple space characters to a single ASCII space, strip leading and trailing space characters. Nemoto & Wang Expires April 30, 2015 [Page 4] Internet-Draft precis mapping October 2014 Case Mapping: For comparison purposes, map uppercase and titlecase characters to lowercase using Unicode Default Case Folding. Local Case Mapping is applicable alternatively. Normalization: NFC. Directionality: The "Bidi Rule" defined in RFC 5893 applies. Exclusions: None. Enforcement: To be specified by applications. Specification: RFC XXXX. 5. References 5.1. Normative References [I-D.ietf-precis-framework] Saint-Andre, P. and M. Blanchet, "PRECIS Framework: Preparation and Comparison of Internationalized Strings in Application Protocols", draft-ietf-precis-framework-18 (work in progress), September 2014. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC5893] Alvestrand, H. and C. Karp, "Right-to-Left Scripts for Internationalized Domain Names for Applications (IDNA)", RFC 5893, August 2010. [Unicode] The Unicode Consortium, "The Unicode Standard, Version 7.0.0", , 2014. [UTR39] The Unicode Consortium, "Unicode Technical Report #39: Unicode Security Mechanisms", , September 2014. 5.2. Informative References [I-D.ietf-precis-mappings] Yoneya, Y. and T. Nemoto, "Mapping characters for PRECIS classes", draft-ietf-precis-mappings-08 (work in progress), June 2014. Authors' Addresses Nemoto & Wang Expires April 30, 2015 [Page 5] Internet-Draft precis mapping October 2014 Takahiro Nemoto Keio University Graduate School of Media Design 4-1-1 Hiyoshi, Kohoku-ku Yokohama, Kanagawa 223-8526 Japan Phone: +81 45 564 2517 Email: t.nemo10@kmd.keio.ac.jp Daniel Wang Keio University Graduate School of Media Design 4-1-1 Hiyoshi, Kohoku-ku Yokohama, Kanagawa 223-8526 Japan Phone: +81 45 564 2517 Email: daniel.wang@kmd.keio.ac.jp Nemoto & Wang Expires April 30, 2015 [Page 6]