    Internet Engineering Task Force (IETF)                          A. Tamas
    Request for Comments: 8589                               B. Phister, Ed.
    Category: Informational                                   J-E. Rodriguez
    ISSN: 2070-1721                                                    OP3FT
                                                                    May 2019

                         The 'leaptofrogans' URI Scheme

    Abstract

       This document describes the 'leaptofrogans' Uniform Resource
       Identifier (URI) scheme, which enables applications to launch Frogans
       Player on a given Frogans site.  Frogans is a medium for publishing
       content and services on the Internet, defined as a generic software
       layer on the Internet.  Frogans Player is software that enables end
       users to browse Frogans sites.

    Status of This Memo

       This document is not an Internet Standards Track specification; it is
       published for informational purposes.

       This document is a product of the Internet Engineering Task Force
       (IETF).  It has been approved for publication by the Internet
       Engineering Steering Group (IESG).  Not all documents approved by the
       IESG are candidates for any level of Internet Standard; see 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/rfc8589.

    Copyright Notice

       Copyright (c) 2019 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
       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.

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    Table of Contents

       1.  Background Information  . . . . . . . . . . . . . . . . . . .   2
         1.1.  About Frogans . . . . . . . . . . . . . . . . . . . . . .   2
         1.2.  About the OP3FT . . . . . . . . . . . . . . . . . . . . .   3
       2.  The Need for a New URI Scheme and Its Purpose . . . . . . . .   3
       3.  Choice of the Scheme Name . . . . . . . . . . . . . . . . . .   4
       4.  Scheme Syntax . . . . . . . . . . . . . . . . . . . . . . . .   5
         4.1.  URI Scheme  . . . . . . . . . . . . . . . . . . . . . . .   5
         4.2.  IRI Usage and Encoding  . . . . . . . . . . . . . . . . .   6
       5.  Trademarks  . . . . . . . . . . . . . . . . . . . . . . . . .   6
       6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
       7.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
       8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
         8.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
         8.2.  Informative References  . . . . . . . . . . . . . . . . .   8
       Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

    1.  Background Information

    1.1.  About Frogans

       Frogans is a medium for publishing content and services on the
       Internet.  From its inception in 1999, the medium was designed as a
       generic software layer running on top of the original Internet
       infrastructure (i.e., the TCP and IP protocols and the Domain Name
       System (DNS)), alongside other existing layers such as E-mail or the
       World Wide Web.

       As a medium, Frogans is not meant for publishing Web sites, but
       Frogans sites, a kind of site founded upon a different format,
       enabling a different kind of communication between end users and
       publishers of content and services.

       Frogans is intended to be complementary to the World Wide Web; it is
       not intended to be a replacement.  This is analogous to instant
       messaging, which was not intended to and did not replace E-mail.

       Compared to the World Wide Web, Frogans suggests publishing content
       and services that involve visual rather than text-based
       communication, focused content rather than long pages, and natural
       interaction rather than complex user interfaces.  For further
       information on the reasons for introducing Frogans on the Internet,
       and for an in-depth discussion of the similarities and differences
       between Frogans sites and Web sites, see [FSDL], Section 1.4
       ("Frogans sites and Web sites").

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       The technology making up the medium, i.e., the Frogans technology,
       includes multiple components such as:

       o  An XML-based language, called Frogans Slide Description Language
          [FSDL], used to develop Frogans sites.

       o  International identifiers, called Frogans addresses [IFAP], used
          to access Frogans sites.  Each Frogans site has its own Frogans
          address.

       o  Browsing software, called Frogans Player, enabling end users to
          browse Frogans sites.  An end user opens a Frogans site by
          entering its Frogans address in Frogans Player.

       o  A registry, called the Frogans Core Registry (FCR), that contains
          all Frogans addresses registered by Frogans site publishers.  The
          registry operator, called the FCR Operator, ensures the resolution
          of Frogans addresses when end users enter them in Frogans Player.

    1.2.  About the OP3FT

       Created in 2012, the Organization for the Promotion, Protection, and
       Progress of Frogans Technology [OP3FT] is a dedicated, non-profit
       organization whose purpose is to hold, promote, protect, and ensure
       the progress of the Frogans technology, in the form of an open
       standard, available to all, free of charge.

       As part of its mission, the OP3FT develops and releases technical
       specifications, reference implementations (including Frogans Player),
       and various policies, which define the rights and responsibilities of
       all stakeholders involved in the technology worldwide.

    2.  The Need for a New URI Scheme and Its Purpose

       Generic software layers running on top of the original Internet
       infrastructure offer mechanisms that enable end users to easily go
       from one layer to another, in both directions.  For example, end
       users can easily launch their usual Web browser on a given Web page
       from a message in their usual E-mail client; in the other direction,
       end users can easily launch their usual E-mail client with a given
       E-mail address from a Web page in their usual Web browser.  This is
       commonly achieved using URIs [RFC3986].

       As regards Frogans as a medium, in the outgoing direction, FSDL
       enables Frogans site publishers to include way-out buttons in their
       Frogans sites.  These buttons enable end users to launch their usual
       Web browser on a given Web page, or to launch their usual E-mail

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       client with a given E-mail address.  This is achieved by associating
       a URI with each of those way-out buttons (the scheme of the URI can
       be any of 'http', 'https', or 'mailto').

       Conversely, in the incoming direction, Web-site publishers should
       have a means to include in their Web pages links that enable end
       users to launch Frogans Player on a given Frogans site.  Likewise,
       people writing E-mail messages should have a means to include in
       their messages links that enable recipients to launch Frogans Player
       on a given Frogans site.  More generally, any end-user application
       should be able to launch Frogans Player on a given Frogans site.

       To achieve this, a new URI scheme, containing a Frogans address, is
       needed.

       Given that Frogans, as a medium, does not enable deep linking for
       Frogans sites, there is no need for additional information in the new
       URI scheme other than the Frogans address.

       The use of a media type as a means to include on a Web page a link
       that enables end users to launch Frogans Player on a given Frogans
       site was tested in 2006 with the registration of the
       'vnd.frogans.ltf' media type with IANA [LTF].  But use of a media
       type was determined to be unsatisfactory for several reasons.  First,
       for any such link included on a Web page, the author of the Web page
       had to create and host a .ltf file on the Web server hosting that Web
       page, which was cumbersome.  Furthermore, prior to creating such
       links, the author had to ask the server administrator to associate
       the .ltf files with the 'vnd.frogans.ltf' media type on the server.
       Alternatively, the author could create a link via a redirection
       service that would generate a .ltf file on the fly while associating
       it with the 'vnd.frogans.ltf' media type.  But that alternative
       raised privacy concerns and potentially added latency for end users.
       Finally, on the Web browser side, it appeared that using a media type
       from a Web page to launch another application did not always work,
       especially on mobile devices.

    3.  Choice of the Scheme Name

       The name chosen for the new URI scheme is 'leaptofrogans'.

       This scheme name was chosen in compliance with [RFC7595], Section 3.8
       ("Scheme Name Considerations").

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       The following shorter names were discussed, but they were not chosen:

       o  'ltf': this name, an acronym for "leap to Frogans", was considered
          insufficiently descriptive, especially for typical end users who
          have little technical knowledge.

       o  'leapto': this name was considered overly general, and it is not
          specifically associated with Frogans.

       o  'frogans': this name was rejected because it could create
          confusion between URIs based on this scheme and those Frogans
          addresses that start with "frogans".

    4.  Scheme Syntax

       Frogans addresses [IFAP] are international identifiers made up of
       Unicode characters.  Thus, a method for encoding non-US-ASCII
       characters is necessary when the new scheme is used as a URI.  The
       new scheme can also be useful as an IRI [RFC3987] in contexts where
       IRIs are allowed.

    4.1.  URI Scheme

       The syntax for the 'leaptofrogans' URI scheme is:

          leaptofrogans-uri = "leaptofrogans:" pct-encoded-frogans-address

       where pct-encoded-frogans-address is a Frogans address compliant with
       [IFAP] and whose Unicode characters are each encoded as follows:

       o  If the character is a US-ASCII character, do not replace it and
          skip to the next character.  Note that according to [IFAP], the
          US-ASCII character cannot be the U+0025 PERCENT SIGN character.

       o  Otherwise, apply steps 1 through 3 below:

          1.  Convert the character to a sequence of one or more octets
              using UTF-8 [UTF-8]

          2.  Convert each octet to %HH, where HH is the hexadecimal
              notation of the octet value.  Note that this is identical to
              the percent-encoding mechanism in Section 2.1 of [RFC3986].

          3.  Replace the original character with the resulting character
              sequence (i.e., a sequence of %HH triplets).

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       Examples of 'leaptofrogans' URIs:

       -  if the Frogans address is the string of US-ASCII characters
          "Network-Name*Site-Name", the URI is as follows:

            leaptofrogans:Network-Name*Site-Name

       -  if the Frogans address is the string of Unicode characters U+7F51,
          U+7EDC, U+540D, U+002A, U+7AD9, U+540D (which is a Chinese
          translation of the Frogans address in the previous example), the
          URI is as follows:

            leaptofrogans:%E7%BD%91%E7%BB%9C%E5%90%8D*%E7%AB%99%E5%90%8D

    4.2.  IRI Usage and Encoding

       The syntax for an IRI corresponding to the 'leaptofrogans' URI scheme
       is:

          leaptofrogans-iri = "leaptofrogans:" frogans-address

       where frogans-address is a Frogans address compliant with [IFAP] and
       encoded in UTF-8 [UTF-8].

       In contexts where both URIs and IRIs are allowed, end-user
       applications can use either a URI or an IRI based on the
       'leaptofrogans' URI scheme when launching Frogans Player on a given
       Frogans site.  This is because Frogans Player must interpret both
       URIs and IRIs based on the 'leaptofrogans' URI scheme.  If the U+0025
       PERCENT SIGN character is found in the string, then the string will
       be interpreted by Frogans Player as a URI; otherwise, it will be
       interpreted as an IRI.

    5.  Trademarks

       In order to enable all users worldwide to use the Frogans technology
       in a clearly defined, secure, and perpetual environment, the OP3FT
       Bylaws [BYLAWS] provide for the implementation of an intellectual
       property policy.

       In this context, the OP3FT is the holder of the "Frogans" trademark
       that is registered in France, the United States, and other countries
       around the world.  The right to use the "Frogans" trademark in
       references or as part of initiatives in connection with the Frogans
       technology is granted in the OP3FT Trademark Usage Policy [OTUP].

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    6.  IANA Considerations

       In accordance with the guidelines and registration procedures for new
       URI schemes [RFC7595], IANA has registered 'leaptofrogans' URI scheme
       as follows:

       Scheme name: 'leaptofrogans'

       Status: Permanent

       Scheme syntax: See Section 4 of RFC 8589.

       Scheme semantics: See Section 2 of RFC 8589.

       Encoding considerations: See Section 4 of RFC 8589.

       Applications/protocols that use this scheme name:  Frogans Player as
          well as any end-user application (such as a Web browser or an
          E-mail client) wishing to launch Frogans Player on a given Frogans
          site.

       Interoperability considerations:  There are no known interoperability
          concerns related to use of the 'leaptofrogans' URI scheme.

       Security considerations: See Section 7 of RFC 8589.

       Contact: Alexis Tamas <mailto:alexis.tamas@op3ft.org>

       Change controller: OP3FT <mailto:contact-standards@op3ft.org>

       References: RFC 8589

    7.  Security Considerations

       The author of a Web page can create a link where the true nature of
       the URI is hidden in the link text that is visible to end users.  The
       same applies for an E-mail message and other end-user applications.

       For URIs based on the 'leaptofrogans' URI scheme, the risk of
       confusion is mitigated because Frogans Player must always display the
       real Frogans address contained in the URI, and it must always require
       confirmation by the end user before opening the corresponding Frogans
       site.

       Also, an end-user application may provide a URI containing a Frogans
       address that is not valid.  This does not represent a risk because,
       before asking for confirmation by the end user, Frogans Player must

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       always verify that the Frogans address contained in the URI is
       compliant with [IFAP], and it must always raise an error if the
       Frogans address is not compliant.

    8.  References

    8.1.  Normative References

       [IFAP]     OP3FT, "International Frogans Address Pattern",
                  Version 1.1, ISBN 978-2-37313-000-3, November 2014,
                  <https://www.frogans.org/en/resources/ifap/access.html>.

       [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
                  Resource Identifier (URI): Generic Syntax", STD 66,
                  RFC 3986, DOI 10.17487/RFC3986, January 2005,
                  <https://www.rfc-editor.org/info/rfc3986>.

       [RFC3987]  Duerst, M. and M. Suignard, "Internationalized Resource
                  Identifiers (IRIs)", RFC 3987, DOI 10.17487/RFC3987,
                  January 2005, <https://www.rfc-editor.org/info/rfc3987>.

       [RFC7595]  Thaler, D., Ed., Hansen, T., and T. Hardie, "Guidelines
                  and Registration Procedures for URI Schemes", BCP 35,
                  RFC 7595, DOI 10.17487/RFC7595, June 2015,
                  <https://www.rfc-editor.org/info/rfc7595>.

       [UTF-8]    Yergeau, F., "UTF-8, a transformation format of ISO
                  10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
                  2003, <https://www.rfc-editor.org/info/rfc3629>.

    8.2.  Informative References

       [BYLAWS]   OP3FT, "Bylaws of the French Fonds de Dotation OP3FT,
                  Organization for the Promotion, Protection and Progress of
                  Frogans Technology", July 2016,
                  <https://www.op3ft.org/en/resources/bylaws/access.html>.

       [FSDL]     OP3FT, "Frogans Slide Description Language", Version 3.0,
                  Preliminary Draft 7, September 2018,
                  <https://www.frogans.org/en/resources/fsdl/access.html>.

       [LTF]      IANA, "Media Types",
                  <https://www.iana.org/assignments/media-types>.

       [OP3FT]    OP3FT, "Organization for the Promotion, Protection and
                  Progress of Frogans Technology", <https://www.op3ft.org/>.

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       [OTUP]     OP3FT, "OP3FT Trademark Usage Policy", March 2017,
                  <https://www.frogans.org/en/resources/otup/access.html>.

    Authors' Addresses

       Alexis Tamas
       OP3FT
       6, Square Mozart
       75016 Paris
       France

       Phone: +33 1 53 92 00 40
       Email: alexis.tamas@op3ft.org

       Benjamin Phister (editor)
       OP3FT
       6, Square Mozart
       75016 Paris
       France

       Phone: +33 1 53 92 00 40
       Email: benjamin.phister@op3ft.org

       Jean-Emmanuel Rodriguez
       OP3FT
       6, Square Mozart
       75016 Paris
       France

       Phone: +33 1 53 92 00 40
       Email: jean-emmanuel.rodriguez@contrib.op3ft.org

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