ENUM -- Telephone Number Mapping A. Mayrhofer Working Group enum.at Internet-Draft August 03, 2006 Expires: February 4, 2007 IANA Registration for vCard Enumservice draft-ietf-enum-vcard-04 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 February 4, 2007. Copyright Notice Copyright (C) The Internet Society (2006). Abstract This memo registers the Enumservice "vCard" with the subtypes "plain", "xml" and "rdf" using the URI schemes "http" and "https" according to the IANA Enumservice registration process described in RFC 3761. This Enumservice is to be used to refer from an ENUM domain name to a vCard instance describing the user of the respective E.164 number. Information gathered from those vCards could be used before, during Mayrhofer Expires February 4, 2007 [Page 1] Internet-Draft vCard Enumservice August 2006 or after inbound or outbound communication takes place. For example, a callee might be presented with the name and association of the caller before picking up the call. Table of Contents 1. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. ENUM Service Registrations - vCard . . . . . . . . . . . . . . 4 3.1. "Plain" Subtype . . . . . . . . . . . . . . . . . . . . . 4 3.2. "RDF" Subtype . . . . . . . . . . . . . . . . . . . . . . 5 3.3. "XML" Subtype . . . . . . . . . . . . . . . . . . . . . . 5 4. Example . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Security & Privacy Considerations . . . . . . . . . . . . . . 6 5.1. The ENUM Record Itself . . . . . . . . . . . . . . . . . . 6 5.2. The Resource Identified . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7 8. Normative References . . . . . . . . . . . . . . . . . . . . . 7 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 9 Intellectual Property and Copyright Statements . . . . . . . . . . 10 Mayrhofer Expires February 4, 2007 [Page 2] Internet-Draft vCard Enumservice August 2006 1. Change Log [Note to editors: This section is to be removed before publication - XML source available on request] draft-ietf-enum-vcard-04 added email address to IANA template (selfcontained) changed number in example to UK drama number added note about line break in example draft-ietf-enum-vcard-03 Fixed typo in abstract Added acks Added text about PII data draft-ietf-enum-vcard-02 added Acknowledgement section clarified security considerations extended introduction sanitized references added subtypes and URI schemes to Abstract draft-ietf-enum-vcard-01 minor title change removed sink type draft-ietf-enum-vcard-00 changed name to reflect WG adoption subtyped Enumservice added "sink" type idea worked on the text draft-mayrhofer-enum-vcard-00 initial draft 2. Introduction 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 RFC 2119 [8]. E.164 Number Mapping (ENUM) [1] uses the Domain Name System (DNS) [2] to refer from E.164 numbers [3] to Uniform Resource Identifiers (URIs) [5]. The registration process for Enumservices is described in section 3 of RFC 3761. "vCard" [6] is a transport independent data format for the exchange Mayrhofer Expires February 4, 2007 [Page 3] Internet-Draft vCard Enumservice August 2006 of information about an individual. For the purpose of this document, the term "vCard" refers to a specific instance of this data format - an "electronic business card". vCards are exchanged via several protocols, most commonly they are distributed as electronic mail attachments or published on web servers. Most popular personal information manager applications are capable of reading and writing vCards. In addition to the format specified in RFC 2426, 'Representing vCard Objects in RDF/XML' [4] specifies two alternative formats for representing vCard data, namely as RDF or "plain" XML documents. The Enumservice specified in this document deals with the relation between an E.164 number and vCards. An ENUM record using this Enumservice identifies a resource from where a vCard corresponding to the respective E.164 number could be fetched. Each subtype of the Enumservice corresponds to one of the vCard data formats mentioned above. Clients could use those resources to eg. automatically update local address books (a Voice over IP phone could try to fetch vCards for all outbound and inbound calls taking place on that phone and display them together with the call journal). In a more integrated scenario, Information gathered from those vCards could even be automatically incorporated into the personal information manager application of the respective user. 3. ENUM Service Registrations - vCard 3.1. "Plain" Subtype Enumservice Name: "vCard" Enumservice Type: "vcard" Enumservice Subtype: "plain" URI Schemes: "http", "https" Functional Specification: This Enumservice indicates that the resource identified is a plain vCard according to RFC 2426 which may be accessed using HTTP/HTTPS [7]. Clients fetching the vCard from the resource indicated should expect access to be restricted. Additionally, the comprehension of the data provided may vary depending on the client's identity. Mayrhofer Expires February 4, 2007 [Page 4] Internet-Draft vCard Enumservice August 2006 Security Considerations: see Section 5 Intended Usage: COMMON Author: Alexander Mayrhofer 3.2. "RDF" Subtype Enumservice Name: "vCard" Enumservice Type: "vcard" Enumservice Subtype: "rdf" URI Schemes: "http", "https" Functional Specification: This Enumservice indicates that the resource identified is a RDF- formatted vCard according to section 3 - 5 of W3C vcard-rdf [4] which may be accessed using HTTP/HTTPS. Clients fetching the vCard from the resource indicated should expect access to be restricted. Additionally, the comprehension of the data provided may vary depending on the client's identity. Security Considerations: see Section 5 Intended Usage: COMMON Author: Alexander Mayrhofer 3.3. "XML" Subtype Enumservice Name: "vCard" Enumservice Type: "vcard" Enumservice Subtype: "xml" URI Schemes: "http", "https" Functional Specification: This Enumservice indicates that the resource identified is a XML- formatted vCard according to section 6 of W3C vcard-rdf [4] which may be accessed using HTTP/HTTPS. Clients fetching the vCard from the resource indicated should expect access to be restricted. Additionally, the comprehension of the data provided may vary depending on the client's identity. Mayrhofer Expires February 4, 2007 [Page 5] Internet-Draft vCard Enumservice August 2006 Security Considerations: see Section 5 Intended Usage: COMMON Author: Alexander Mayrhofer 4. Example An example ENUM entry referencing to a plain vCard could look like: $ORIGIN 6.4.9.0.6.4.9.7.0.2.4.4.e164.arpa. @ IN NAPTR 100 10 "u" "E2U+vcard:plain" "!^.*$!http://example.net/vcard.vcf!" . (Note: Due to line length constraints, the example record above is split in two lines) 5. Security & Privacy Considerations 5.1. The ENUM Record Itself Since ENUM uses DNS - a publicly available database - any information contained in records provisioned in ENUM domains must be considered public as well. Even after revoking the DNS entry and removing the refered resource, copies of the information could still be available. Information published in ENUM records could reveal associations between E.164 numbers and their owners - especially if URIs contain personal identifiers or domain names for which ownership information can be obtained easily. However, it is important to note that the ENUM record itself does not need to contain any personal information. It just points to a location where access to personal information could be granted. ENUM records pointing to third party resources can easily be provisioned on purpose by the ENUM domain owner - so any assumption about the association between a number and an entity could therefore be completely bogus unless some kind of identity verification is in place. This verification is out of scope for this memo. 5.2. The Resource Identified In most cases, vCards provide information about individuals. Linking telephone numbers to such Personally Identifyable Information (PII) is a very sensitive topic, because it provides a "reverse lookup" Mayrhofer Expires February 4, 2007 [Page 6] Internet-Draft vCard Enumservice August 2006 from the number to its owner. Publication of such PII is covered by data protection law in many legislations. In most cases, the explicit consent of the affected individual is required. Users MUST therefore carefully consider information they provide in the resource identified by the ENUM record as well as in the record itself. Considerations SHOULD include serving information only to entities of the user's choice and/or limiting the comprehension of the information provided based on the requesting entity. On the other hand, most of the information which a vCard would typically contain is already available via more "traditional" sources like white pages and offline/online directories, especially if those resources already allow "reverse lookups" (using phone numbers as the search key). In such cases, publishing a vCard on the internet and associating it to a phone number does not neccessarily increase the amount of available information. It may, however, ease access to this information (which is actually the intention of this Enumservice in the first place). If access restrictions on the vCard resource are deployed, Standard HTTP mechanisms MUST be used to enforce those restrictions. HTTPS SHOULD be preferred if the deployed mechanisms are prone to eavesdropping and replay attacks. 6. IANA Considerations This memo requests registration of the "vCard" Enumservice according to the definitions in this document and RFC 3761 [1]. 7. Acknowledgements The author wishes to thank David Lindner for his contributions during the early stages of this document. In addition, Klaus Nieminen and Ondrej Sury provided helpful suggestions. 8. Normative References [1] Faltstrom, P. and M. Mealling, "The E.164 to Uniform Resource Identifiers (URI) Dynamic Delegation Discovery System (DDDS) Application (ENUM)", RFC 3761, April 2004. [2] Mockapetris, P., "Domain names - Implementation and Specification", STD 13, RFC 1035, November 1987. [3] ITU-T, "The international public telecommunication numbering Mayrhofer Expires February 4, 2007 [Page 7] Internet-Draft vCard Enumservice August 2006 plan", Recommendation E.164 (02/05), Feb 2005. [4] Iannella, R., "Representing vCard Objects in RDF/XML", W3C NOTE NOTE-vcard-rdf-20010222, February 2001. [5] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [6] Dawson, F. and T. Howes, "vCard MIME Directory Profile", RFC 2426, September 1998. [7] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. [8] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. Mayrhofer Expires February 4, 2007 [Page 8] Internet-Draft vCard Enumservice August 2006 Author's Address Alexander Mayrhofer enum.at GmbH Karlsplatz 1/9 Wien A-1010 Austria Phone: +43 1 5056416 34 Email: alexander.mayrhofer@enum.at URI: http://www.enum.at/ Mayrhofer Expires February 4, 2007 [Page 9] Internet-Draft vCard Enumservice August 2006 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. 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