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Versions: 00 01

Network Working Group                                          J. Miller
Internet-Draft                                            P. Saint-Andre
Intended status: Informational
Expires: June 13, 2008                                       F. Stutzman
                                                                 ClaimID
                                                       December 11, 2007


                                MicroID
                        draft-miller-microid-01

Status of this Memo

   By submitting this Internet-Draft, each author represents that any
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   This Internet-Draft will expire on June 13, 2008.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   This specification defines MicroID, a lightweight identity technology
   that enables the creation of a portable identity token based on any
   two Uniform Resource Identifiers.






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Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.2.  Terminology  . . . . . . . . . . . . . . . . . . . . . . .  3
     1.3.  Discussion Venue . . . . . . . . . . . . . . . . . . . . .  3
     1.4.  Acknowledgements . . . . . . . . . . . . . . . . . . . . .  3
   2.  Format . . . . . . . . . . . . . . . . . . . . . . . . . . . .  3
   3.  Generation . . . . . . . . . . . . . . . . . . . . . . . . . .  4
   4.  Processing . . . . . . . . . . . . . . . . . . . . . . . . . .  5
   5.  Meaning  . . . . . . . . . . . . . . . . . . . . . . . . . . .  5
     5.1.  Overview . . . . . . . . . . . . . . . . . . . . . . . . .  5
     5.2.  Generating Applications  . . . . . . . . . . . . . . . . .  7
     5.3.  Using Technologies . . . . . . . . . . . . . . . . . . . .  8
   6.  Internationalization Considerations  . . . . . . . . . . . . .  9
   7.  Security Considerations  . . . . . . . . . . . . . . . . . . . 10
   8.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
     8.1.  Normative References . . . . . . . . . . . . . . . . . . . 10
     8.2.  Informative References . . . . . . . . . . . . . . . . . . 10
   Appendix A.  Legacy Support  . . . . . . . . . . . . . . . . . . . 11
   Appendix B.  Copying Conditions  . . . . . . . . . . . . . . . . . 11
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
   Intellectual Property and Copyright Statements . . . . . . . . . . 13




























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1.  Introduction

1.1.  Overview

   MicroID is a lightweight identity technology that enables the
   creation of a portable identity token from any two Uniform Resource
   Identifiers [URI].

   Such identity tokens are desirable because they:

   o  Enable individuals to assert ownership over information published
      and reputation earned on the Internet in a granular manner.
   o  Enable service providers to "stamp" information and reputation
      based on a validated URI associated with an individual who uses
      the service.

1.2.  Terminology

   The following keywords as used in this document are to be interpreted
   as described in [TERMS]: "MUST", "SHALL", "REQUIRED"; "MUST NOT",
   "SHALL NOT"; "SHOULD", "RECOMMENDED"; "SHOULD NOT", "NOT
   RECOMMENDED"; "MAY", "OPTIONAL".

1.3.  Discussion Venue

   The preferred discussion forum for this specification is the MicroID
   mailing list; subscription information is located at
   <http://lists.ibiblio.org/mailman/listinfo/microid> and the mailing
   list archives are located at
   <http://lists.ibiblio.org/pipermail/microid/>.

1.4.  Acknowledgements

   Thanks to James Cridland, Yaniv Golan, David Koblas, Paco Nathan,
   Will Norris, Evan Prodromou, Chris Roos, Terrell Russell, Eran
   Sandler, and Brian Suda for their feedback.


2.  Format

   The syntax for a MicroID is defined as follows, using the Augmented
   Backus-Naur Form specified in [ABNF].









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   microid = inputs ":" algo ":" hash
   inputs  = scheme "+" scheme
   scheme  = ALPHA *( ALPHA / DIGIT / "+" / "-" / "." )
             ; a URI scheme name (e.g., mailto)
   algo    = ALPHA *( ALPHA / DIGIT )
             ; the short name of a hashing
             ; algorithm (e.g., sha256),
   hash    = *( ALPHA / DIGIT )
             ; a hash of the URIs for both entities

   Note: If the URI scheme name includes the "+" character (which is
   allowed by [URI] but not in common use), that character MUST be
   escaped to %2B.

   Note: The algorithm names should be as registered with the IANA in
   the Hash Function Textual Names registry located at
   <http://www.iana.org/assignments/hash-function-text-names>, but may
   exclude the "-" character (e.g., "sha1" rather than "sha-1").

   Note: See the Legacy Support (Appendix A) section of this document
   for information regarding the original MicroID format.


3.  Generation

   The method for generating the hash is:

   hash = algo(
               algo(EntityURI)
               +
               algo(EntityURI)
              )

   The "algo" MAY be any recognized hashing algorithm, such as those
   defined in [SHA].  Support for the sha1 and sha256 algorithms is
   REQUIRED for interoperability.  The output MUST be in hexadecimal
   (not base64) format.  The same algorithm MUST be used for all hashing
   functions when generating a given MicroID.

   The "EntityURI" MAY conform to any URI scheme, such as [HTTP],
   [MAILTO], [SIP], or [XMPP].

   As an example, consider the following inputs, from which a MicroID is
   generated using the sha1 algorithm:

   o  The first entity is an individual identified by an XMPP URI of
      "xmpp:stpeter@jabber.org".




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   o  The second entity is a service provider identified by an HTTP URI
      of "https://www.xmpp.net/".

   The hash is generated as follows (note: the line break in the third
   example is included only for the sake of readability):

   sha1(
        sha1(xmpp:stpeter@jabber.org)
        +
        sha1(https://www.xmpp.net/)
       )

   sha1(
        afa6353518f818af2f036da336c3097dedc00dee
        +
        3115de01ebfa34a34314060b5f30038b0fa359f8
       )

   sha1(
   afa6353518f818af2f036da336c3097dedc00dee
   3115de01ebfa34a34314060b5f30038b0fa359f8
       )

   6196ea6709be2a4cbdf2bc0cfaeac491f2fb8921

   Thus in accordance with the format previously described the issued
   MicroID is:

   xmpp+https:sha1:6196ea6709be2a4cbdf2bc0cfaeac491f2fb8921


4.  Processing

   A processing application MAY use only the hash portion of the MicroID
   for comparison purposes.  An implementation SHOULD be liberal in
   accepting MicroIDs that conform to the legacy format; for details,
   see the Legacy Support (Appendix A) section of this document.


5.  Meaning

5.1.  Overview

   By itself, a MicroID has no inherent meaning, since it is simply a
   string created from two URIs.  Any entity can generate a MicroID even
   if it has not verified the identity of the resources associated with
   one or both URIs.  Furthermore, a MicroID is easily copied by an
   entity that did not generate it.  Finally, a MicroID is not digitally



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   signed by the entity that generated it and therefore cannot be
   cryptographically associated with the generating entity.

   Therefore it may be wondered: what is the meaning of a MicroID?  The
   answer is: any meaning imputed to a MicroID results from the context
   in which it is used.  That context includes the nature of the
   generating application and the nature of the using technology.

   Some possible generating applications and using technologies are
   described in the following sections.  We use the following terms to
   describe the parties involved in the generation and processing of a
   MicroID:

   o  Consumer -- Any party that reads a MicroID issued by an Issuer (in
      other identity systems, a consumer is sometimes called a relying
      party).
   o  Entity -- Either party identified by a URI or IRI that is used to
      construct a MicroID.
   o  Individual -- An entity that generates information or earns
      reputation.
   o  Issuer -- The party that generates a MicroID.  The issuer can be a
      third party and need not be an entity.
   o  Service Provider -- An entity that is responsible for hosting
      information or reputation; a service provider may or may not be an
      issuer.

   A MicroID should be generated by an issuer, not by an individual.
   The issuer may be the service provider that hosts the information
   about, content created by, or reputation earned by an individual, or
   it may be a third party trusted by both the individual and the
   service provider.

   An issuer should not generate a MicroID until it has verified that
   the individual or service provider has control over a given entity
   URI.  Methods for such verification are out of scope for this
   specification and may vary according to local service policies and
   the URI scheme in question.

   The first entity URI should be that of the individual and the second
   EntityURI should be that of the service provider.  Any given entity
   URI may have meaning above and beyond that encapsulated in the
   relevant URI scheme; for example, the HTTP URI for an individual
   could be hosted by an OpenID service (see <http://openid.net/>).
   However, MicroID places no restrictions on the semantics of a given
   entity URI.






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5.2.  Generating Applications

5.2.1.  Service Provider

   It is envisioned that one common deployment scenario will be that of
   a service provider "stamping" information or reputation that is
   hosted by the service provider on behalf of individuals.  In this
   architecture, the service provider is both the issuer and one of the
   entities, where the other entity is an individual.

        +--------+
        | Entity |
        +--------+
            |
            | registration
            |
   +-------------------+
   | Service Provider  |
   | (Entity + Issuer) |
   +-------------------+
            |
            | issuance
            |
         MicroID

   Whether a given consumer imputes meaning to the MicroID in this
   scenario depends on the consumer's relationship to the service
   provider, whether the consumer has some trust in the information
   presented by the service provider, etc.

5.2.2.  Third Party as Issuer

   Another scenario is that in which the MicroID is issued by a trusted
   third party (e.g., a part with which both a service provider and
   individual have registered).  In this architecture, the service
   provider is merely one of the entities.















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   +--------+    +------------------+
   | Entity |    | Service Provider |
   +--------+    +------------------+
       |                 |
       |                 |
       +-----------------+
              |
              | registration
              |
          +--------+
          | Issuer |
          +--------+
              |
              | issuance
              |
           MicroID

   Whether a given consumer imputes meaning to the MicroID in this
   scenario depends on the consumer's relationship to the third part,
   whether the consumer has some trust in the information presented by
   the third party, whether the consumer is one of the entities, etc.

5.3.  Using Technologies

   This specification does not limit the technologies that might make
   use of MicroIDs, and future versions of this specification might
   describe a wide range of such uses.  Here we describe two such uses.

   Note: The scope of information (e.g., markup) covered by a MicroID
   depends on the nature of the using technology and must be defined
   separately by each using technology.

5.3.1.  HTML Class Attribute

   One possible use is to include a MicroID in the HyperText Markup
   Language [HTML] class attribute.  The recommended format is to
   prepend the MicroID itself with the string "microid-", as shown in
   the following example:

   <p class='microid-xmpp+https:sha1:
   6196ea6709be2a4cbdf2bc0cfaeac491f2fb8921'>
   mycontent</p>

   In this usage, the scope of the MicroID is all information contained
   within the element that possesses the class attribute, whether that
   information is represented as attributes, character data, or child
   elements.  However, any given child element may itself possess a
   class attribute specifying a MicroID that overrides the content claim



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   asserted by the parent element.  In all cases, the relevant claim is
   always that of the nearest containing element in the hierarchy.

   A MicroID can be used on its own to mark content as created by a
   certain individual (e.g., a comment made on a web forum):

   <div class='
   microid-xmpp+https:sha1:6196ea6709be2a4cbdf2bc0cfaeac491f2fb8921'>
     <p>This is a great idea!</p>
   </div>

   A MicroID can be also used in concert with other lightweight identity
   technologies such as the rel='me' value defined by XHTML Friends
   Network (XFN) as specified at <http://gmpg.org/xfn/11>:

   <div class='
     microid-xmpp+https:sha1:6196ea6709be2a4cbdf2bc0cfaeac491f2fb8921'>
     <p>This is a great idea!</p>
     <p>--<a rel='me'
             href='http://2idi.com/contact/=stpeter'>
             stpeter</a></p>
   </div>

5.3.2.  HTML Meta Data

   Another possible use is in meta data about an [HTML] file (e.g., to
   signify that a given web page is created by, owned by, or about a
   given Individual).  This is done by including a <meta/> tag whose
   'name' attribute is "microid" and whose 'content' attribute specifies
   the MicroID, as shown in the following example:

  <meta
    name='microid'
    content='xmpp+https:sha1:6196ea6709be2a4cbdf2bc0cfaeac491f2fb8921'/>

   In this usage, the scope of the MicroID is the page itself.  However,
   the whole-page claim represented in the META tag can be overridden by
   claims represented in class attributes possessed by elements within
   the HTML body.

   A file MAY contain multiple META tags with a name of "microid" (e.g.,
   to claim ownership by multiple authors or to represent multiple
   identities associated with the same individual).


6.  Internationalization Considerations

   A MicroID SHOULD be constructed using two Uniform Resource



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   Identifiers [URI] but one or both inputs MAY instead be an
   Internationalized Resource Identifier [IRI].


7.  Security Considerations

   MicroID is a technology for identifying the ownership or authorship
   of information on the Internet.  It is not a mechanism for
   authentication, authorization, security, or encryption.  Use of
   MicroID technology results only in weak verification of identities
   (if any).  MicroID may be susceptible to [DNS] poisoning attacks
   unless [DNSSEC] is used, since most URIs depend on DNS.


8.  References

8.1.  Normative References

   [ABNF]    Crocker, D. and P. Overell, "Augmented BNF for Syntax
             Specifications: ABNF", RFC 4234, October 2005.

   [SHA]     National Institute of Standards and Technology, "Secure
             Hash Standard", FIPS PUB 180-2, August 2002, <http://
             csrc.nist.gov/publications/fips/fips180-2/
             fips180-2withchangenotice.pdf>.

   [TERMS]   Bradner, S., "Key words for use in RFCs to Indicate
             Requirement Levels", BCP 14, RFC 2119, March 1997.

   [URI]     Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
             Resource Identifier (URI): Generic Syntax", STD 66,
             RFC 3986, January 2005.

8.2.  Informative References

   [DNS]     Mockapetris, P., "Domain names - implementation and
             specification", STD 13, RFC 1035, November 1987.

   [DNSSEC]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
             Rose, "DNS Security Introduction and Requirements",
             RFC 4033, March 2005.

   [HTML]    Jacobs, I., Raggett, D., and A. Hors, "HTML 4.01
             Specification", World Wide Web Consortium
             Recommendation REC-html401-19991224, December 1999,
             <http://www.w3.org/TR/1999/REC-html401-19991224>.

   [HTTP]    Fielding, R., Gettys, J., Mogul, J., Frystyk, H., Masinter,



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             L., Leach, P., and T. Berners-Lee, "Hypertext Transfer
             Protocol -- HTTP/1.1", RFC 2616, June 1999.

   [IRI]     Duerst, M. and M. Suignard, "Internationalized Resource
             Identifiers (IRIs)", RFC 3987, January 2005.

   [MAILTO]  Hoffman, P., Masinter, L., and J. Zawinski, "The mailto URL
             scheme", RFC 2368, July 1998.

   [SIP]     Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
             A., Peterson, J., Sparks, R., Handley, M., and E. Schooler,
             "SIP: Session Initiation Protocol", RFC 3261, June 2002.

   [XMPP]    Saint-Andre, P., "Internationalized Resource Identifiers
             (IRIs) and Uniform Resource Identifiers (URIs) for the
             Extensible Messaging and Presence Protocol (XMPP)",
             RFC 4622, August 2006.


Appendix A.  Legacy Support

   MicroID originally assumed the use of sha1 as the hashing algorithm
   and did not specify the schemes of the EntityURI inputs, resulting in
   the following format:

   microid = hash
   hash    = *( ALPHA / DIGIT )
             ; a hash of the URIs for both entities

   For example, using the same inputs as shown in the body of this
   specification, the MicroID in legacy format would be:

   6196ea6709be2a4cbdf2bc0cfaeac491f2fb8921

   An implementation MUST generate MicroIDs in the format specified in
   the Format (Section 2) section of this document, but SHOULD process
   MicroIDs generated using the legacy format for the sake of backward
   compatibility.


Appendix B.  Copying Conditions

   The Contributors grant third parties the irrevocable right to copy,
   use and distribute the Contribution, with or without modification, in
   any medium, without royalty, provided that, unless separate
   permission is granted, redistributed modified works:





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   1.  do not contain misleading author, version, name of work, or
       endorsement information, and
   2.  do not claim endorsement of the modified work by the
       Contributors, or any organizations the Contributors belong to,
       the Internet Engineering Task Force (IETF), Internet Research
       Task Force (IRTF), Internet Engineering Steering Group (IESG),
       Internet Architecture Board (IAB), Internet Assigned Numbers
       Authority (IANA), Internet Society (ISOC), Request For Comments
       (RFC) Editor, or any combination or variation of such terms
       (including without limitation the IETF "4 diamonds" logo), or any
       terms that are confusingly similar thereto, and
   3.  remove any claims of status as an Internet Standard, including
       without limitation removing the RFC boilerplate.

   The IETF suggests that any citation or excerpt of unmodified text
   reference the RFC or other document from which the text is derived.


Authors' Addresses

   Jeremie Miller

   Email: jeremie@jabber.org


   Peter Saint-Andre

   Email: stpeter@jabber.org
   URI:   https://stpeter.im/


   Fred Stutzman
   ClaimID

   Email: fred@metalab.unc.edu
















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Full Copyright Statement

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Acknowledgment

   Funding for the RFC Editor function is provided by the IETF
   Administrative Support Activity (IASA).





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