Network Working Group J. Snell Internet-Draft September 23, 2005 Expires: March 27, 2006 Feed License Link Relation draft-snell-atompub-feed-license-03.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on March 27, 2006. Copyright Notice Copyright (C) The Internet Society (2005). Abstract This memo presents a mechanism that allows feed publishers to associate copyright licenses with feeds and entries. Snell Expires March 27, 2006 [Page 1] Internet-Draft Feed Thread September 2005 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Notational Conventions . . . . . . . . . . . . . . . . . . . . 3 3. The 'license' link relation . . . . . . . . . . . . . . . . . 3 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Author's Address . . . . . . . . . . . . . . . . . . . . . . . 5 A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 5 Intellectual Property and Copyright Statements . . . . . . . . 6 Snell Expires March 27, 2006 [Page 2] Internet-Draft Feed Thread September 2005 1. Introduction This document specifies a mechanism that allows feed publishers the ability to associate copyright licenses with the informational content of an entry. Licenses associated using these mechanisms MAY or MAY not be machine readable and are intended to communicate the various rights and obligations others may have with regards to given resource. 2. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14, [RFC2119], as scoped to those conformance targets. In this specification, "entry" refers to an atom:entry element. In this specification, "feed" refers to an Atom Feed Document. In this specification, "head section" refers to the children of a feed's document-wide metadata container; e.g., the child elements of the atom:feed element in an Atom Feed Document. In this specification, "link" refers to the atom:link element. In this specification, "link relation" refers to the value of the atom:link element's rel attribute. 3. The 'license' link relation The 'license' link relation is used to associate a copyright license with Atom Feed and Entry Documents. o atom:entry elements MAY contain any number of 'license' link relations. o atom:feed elements MAY contain any number of 'license' link relations. o atom:source elements MAY contain any number of 'license' link relations. o atom:entry, atom:feed and atom:source elements MUST NOT contain more than one 'license' link relation with the same combination of type and hreflang attribute values. License link relations appearing as children of the atom:feed or atom:source elements apply only to the informational content of the containing element, and not to the informational content of any associated atom:entry elements. That is, the presence of a license Snell Expires March 27, 2006 [Page 3] Internet-Draft Feed Thread September 2005 link in the head section of a feed document does not extend a license over the various contained entry elements. For example http://www.example.com/myfeed My Example Feed 2005-07-28T12:00:00Z James tag:entries.com,2005:1 My original entry This is my original entry Multiple license link relations MAY be used to indicate that the informational content has been published under multiple copright licenses. In such instances, each of the linked licenses is considered to be mutually exclusive of the others. That is to say, for example, if an entry contains license links to both a Creative Commons License and the General Public License (GPL), the informational content is considered to be licensed either as "Creative Commons OR GPL" as opposed to "Creative Commons AND GPL". If multiple license link relations are specified, each SHOULD contain a title attribute that specifies a human readable label for each license link. 4. Security Considerations Feeds using the mechanisms described here could be crafted in such a way as to cause a consumer to initiate excessive (or even an unending sequence of) network requests, causing denial of service (either to the consumer, the target server, and/or intervening networks). This risk can be mitigated by requiring user intervention after a certain number of requests, or by limiting requests either according to a hard limit, or with heuristics. Malicious interediaries could also attempt to change the licensing of an atom:feed, atom:entry or atom:source by substituting a new URI for Snell Expires March 27, 2006 [Page 4] Internet-Draft Feed Thread September 2005 the 'license' link relation. This risk can be mitigated by digitally signing the elements in which the 'license' link relations appear. 5. IANA Considerations This specification defines one new Atom link relation type to be registered in the IANA Registry of Link Relations as defined by [I-D.ietf-atompub-format]. Attribute Value: license Description: (see section 3) Expected display characteristics: (see section 3) Security considerations: (see section 4) 6. References [I-D.ietf-atompub-format] Sayre, R. and M. Nottingham, "The Atom Syndication Format", draft-ietf-atompub-format-11 (work in progress), August 2005. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [W3C.REC-xml-infoset-20040204] Tobin, R. and J. Cowan, "XML Information Set (Second Edition)", W3C REC REC-xml-infoset-20040204, February 2004. Author's Address James M Snell Phone: Email: jasnell@gmail.com URI: http://snellspace.com Appendix A. Acknowledgements The author gratefully acknowledges the feedback from Mike Linksvayer, Robin Cover, and the members of Atom Publishing Format and Protocol working group during the development of this specification. Snell Expires March 27, 2006 [Page 5] Internet-Draft Feed Thread September 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Disclaimer of Validity This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Copyright Statement Copyright (C) The Internet Society (2005). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. Acknowledgment Funding for the RFC Editor function is currently provided by the Internet Society. Snell Expires March 27, 2006 [Page 6]