[Docs] [txt|pdf] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]
Versions: (draft-kucherawy-reputation-media-type)
00 01 02 03 04 05 06 07 08 09 10 11
12 13 RFC 7071
REPUTE Working Group N. Borenstein
Internet-Draft Mimecast
Intended status: Standards Track M. Kucherawy
Expires: May 23, 2013 November 19, 2012
A Media Type for Reputation Interchange
draft-ietf-repute-media-type-05
Abstract
This document defines a media type for exchanging reputation
information about an arbitrary class of object.
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/.
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."
This Internet-Draft will expire on May 23, 2013.
Copyright Notice
Copyright (c) 2012 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
(http://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.
Borenstein & Kucherawy Expires May 23, 2013 [Page 1]
Internet-Draft Reputation Media Type November 2012
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Definitions . . . . . . . . . . . . . . . . . 3
2.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 3
2.2. Other Definitions . . . . . . . . . . . . . . . . . . . . 3
3. Description . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Reputon Keys . . . . . . . . . . . . . . . . . . . . . . . 4
3.2. Reputon Structure . . . . . . . . . . . . . . . . . . . . 5
3.3. Example Reply . . . . . . . . . . . . . . . . . . . . . . 6
4. Scores . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8
5.1. application/reputon Media Type Registration . . . . . . . 8
5.2. Reputation Applications Registry . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . . 11
Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 12
Appendix B. Public Discussion . . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 12
Borenstein & Kucherawy Expires May 23, 2013 [Page 2]
Internet-Draft Reputation Media Type November 2012
1. Introduction
This document defines a media type for use when answering a
reputation query using the "long form" query defined in
[I-D.REPUTE-QUERY-HTTP], which uses [HTTP].
Also included is the specification for an IANA registry to contain
definitions and symbolic names for known reputation applications and
corresponding response sets.
2. Terminology and Definitions
This section defines terms used in the rest of the document.
2.1. Key Words
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 [KEYWORDS].
2.2. Other Definitions
Other terms of importance in this document are defined in
[I-D.REPUTE-MODEL], the base document in this document series.
3. Description
A "reputon" is a single independent object containing reputation
information. A particular query about a subject of interest will
receive one or more reputons in response, depending on the nature of
the data collected and reported by the server.
The format selected for the representaton of a reputon is Javascript
Object Notation (JSON), defined in [JSON]. Accordingly, a new media
type, "application/reputon+json", is defined for the JSON
representation of reputational data, typically in response to a
client making a request for such data about some subject. This media
type has one optional parameter, "app", which defines the specific
reputation application in whose context the query is made and the
response returned. If absent, a generic reputation query is assumed
for which only a simple reply is allowed.
The body of the media type consists of a JSON document that contains
the reputation information requested. A detailed description of the
expected structure of the reply is provided below.
Borenstein & Kucherawy Expires May 23, 2013 [Page 3]
Internet-Draft Reputation Media Type November 2012
3.1. Reputon Keys
The key pieces of data found in a reputon for all reputation
applications are defined as follows:
rater: The identity of the entity providing the reputation
information, typically expressed as a DNS domain name.
assertion: A keyword indicating the specific assertion or claim
being rated. In the absence of an "app" parameter on the media
type, the reputon can only indicate generic goodness, with the
default assertion "is-good", but each application is expected to
define additional assertions.
rated: The identity of the entity being rated. The nature of this
field is application-specific; it could be domain names, email
addresses, driver's license numbers, or anything that uniquely
identifies the entity being rated. Documents that define specific
reputation applications are required to define syntax and
semantics for this field.
rating: The overall rating score for that entity, expressed as a
floating-point number between 0.0 and 1.0 inclusive. See
Section 4 for discussion.
The following are OPTIONAL for all applications, to be used in
contexts where they are appropriate:
confidence: The level of confidence the reputation provider has in
the value presented being accurate, expressed as a floating-point
number between 0.0 and 1.0 inclusive.
rater-authenticity: The level of confidence in that identity being
genuine, expressed as a floating-point number between 0.0 and 1.0
inclusive.
sample-size: The number of data points used to compute that score,
possibly an approximation. Expressed as an unsigned 64-bit
integer. The units are deliberately not specified, since not all
reputation service providers will collect data the same way.
Consumers will need to determine out-of-band the units being
reported and apply this value accordingly within their local
policies.
updated: A timestamp indicating when this value was generated.
Expressed as the number of seconds since January 1, 1970 00:00
UTC.
Borenstein & Kucherawy Expires May 23, 2013 [Page 4]
Internet-Draft Reputation Media Type November 2012
A particular application that registers itself with IANA MAY also
define additional application-specific attribute/value pairs beyond
these standard ones.
Further, particular application service providers MAY provide local
extensions to registered applications. Syntax for these will need to
be specified and accommodated privately between clients and servers.
3.2. Reputon Structure
A reputon expressed in JSON consists of an object that itself
contains zero or more objects whose names are "reputon". Each
reputon object is a set of key-value pairs, where the keys are the
names of particular properties that comprise a reputon (as listed
above, or as provided with specific applications), and values are the
content associated with those keys. The set of keys that make up a
reputon within a given application are known as that application's
"response set".
Thus, the following simple example:
Content-type: application/reputon+json
{
"reputon":
{
"rater": "RatingsRUs.example.com",
"rater-authenticity": 1.0,
"assertion": "is-good",
"rated": "Alex Rodriguez",
"rating": 0.99,
"sample-size": 50000
}
}
...indicates we are absolutely sure (1.0) that the entity
"RatingsRUs.example.com" consolidated 50000 data points (perhaps from
everyone in Yankee Stadium) and concluded that Alex Rodriguez is very
very good (0.99) at something. It doesn't tell us what he's good at,
and while it might be playing baseball, it could just as well be
paying his taxes on time.
A more sophisticated usage would define a baseball application with a
response set of specific assertions, so that this example:
Borenstein & Kucherawy Expires May 23, 2013 [Page 5]
Internet-Draft Reputation Media Type November 2012
Content-type: application/reputon+json; app="baseball"
{
"reputon":
{
"rater": "baseball-reference.example.com",
"rater-authenticity": 1.0,
"assertion": "hits-for-power",
"rated": "Alex Rodriguez",
"rating": 0.99,
"sample-size": 50000
}
}
...would indicate that 50000 fans polled by the entity baseball-
reference.example.com rate A-Rod very highly in hitting for power,
whereas this example:
Content-type: application/reputon+json; app="baseball"
{
"reputon":
{
"rater": "baseball-reference.example.com",
"rater-authenticity": 1.0,
"assertion": "clutch-hitter",
"rated": "Alex Rodriguez",
"rating": 0.4,
"sample-size": 50000
}
}
...would indicate that a similar poll indicated a somewhat weaker
consensus that A-Rod tends to choke in critical baseball situations.
In practice, most usage of reputons is expected to make use of the
"app" parameter to target an application-specific set of assertions.
3.3. Example Reply
The following is an example reputon generated using this schema,
including the media type definition line:
Borenstein & Kucherawy Expires May 23, 2013 [Page 6]
Internet-Draft Reputation Media Type November 2012
Content-Type: application/reputon+json; app="email-id"
{
"reputon":
{
"rater": "rep.example.net",
"rater-authenticity": 0.95,
"assertion": "spam",
"identity": "dkim",
"rated": "example.com",
"rating": 0.012,
"sample-size": 16938213,
"updated": 1317795852
}
}
Here, reputation agent "rep.example.net" is asserting within the
context of the "email-id" application that "example.com" appears to
be associated with spam 1.2% of the time, based on just short of 17
million messages analyzed or reported to date. The "email-id"
application has declared the extension key "identity" to indicate how
the subject identifier was used in the observed data, establishing
some more specific semantics for the "rating" value. In this case,
the extension is used to show the identity "example.com", the subject
of the query, is extracted from the analyzed messages using the
[DKIM] "d=" parameter for messages where signatures validate. The
reputation agent is 95% confident of this result. (See
[I-D.REPUTE-EMAIL-IDENTIFIERS] for details about the registered email
identifiers application.)
4. Scores
The score presented as the value in the rating parameter appears as a
floating point value between 0.0 and 1.0 inclusive. The intent is
that the definition of an assertion within an application will
declare what the anchor values 0.0 and 1.0 specifically mean.
Generally speaking, 1.0 implies full agreement with the assertion,
while 0.0 indicates no support for the assertion.
The definition will also specify the type of scale in use when
generating scores, to which all reputation service providers for that
application space must adhere. This will allow a client to change
which reputation service provider is being queried for a given
without having to learn through some out-of-band method what the new
provider's values mean. For example, a registration might state that
ratings are linear, which would mean a score of "x" is twice as
strong as a value of "x/2".
Borenstein & Kucherawy Expires May 23, 2013 [Page 7]
Internet-Draft Reputation Media Type November 2012
5. IANA Considerations
This document presents two actions for IANA, namely the creation of
the new media type "application/reputon+json" and the creation of a
registry for reputation application types. Another document in this
series creates an initial registry entry for the latter.
5.1. application/reputon Media Type Registration
This section provides the media type registration application from
[MIME-REG] for processing by IANA:
To: media-types@iana.org
Subject: Registration of media type application/reputon
Type name: application
Subtype name: reputon+json
Required parameters: none
Optional parameters:
app: Names the reputation application in use within the reputon,
which defines the valid assertions and any extensions that may
also be valid (i.e., the response set) for that application.
These MUST be registered with IANA.
Encoding considerations: "7bit" encoding is sufficient and MUST be
used to maintain readability when viewed by non-MIME mail readers.
Security considerations: See Section 6 of [this document].
Interoperability considerations: Implementers MUST ignore any "app"
values, attribute/value pairs, or response set items they do not
support.
Published specification: [this document]
Applications that use this media type: Any application that wishes
to query a service that provides reputation data using the "long
form" defined in [I-D.REPUTE-QUERY-HTTP]. The example application
is one that provides reputation expressions about DNS domain names
found in email messages.
Borenstein & Kucherawy Expires May 23, 2013 [Page 8]
Internet-Draft Reputation Media Type November 2012
Additional information: The value of the "app" parameter MUST also
be registered with IANA.
Person and email address to contact for further information:
Nathaniel Borenstein <nps@guppylake.com>
Murray S. Kucherawy <msk@cloudmark.com>
Intended usage: COMMON
Author:
Nathaniel Borenstein
Murray S. Kucherawy
Change controller: IESG
5.2. Reputation Applications Registry
IANA is requested to create the "Reputation Applications" registry.
This registry will contain names of applications used with the
application/reputon+json media type (and other media types that carry
reputons), as defined by this document.
New registrations or updates MUST be published in accordance with the
"Specification Required" guidelines as described in
[IANA-CONSIDERATIONS].
New registrations and updates are to contain the following
information:
1. Name of the application being registered or updated
2. Short description of the application (i.e., the class of entity
about which it reports reputation data)
3. The document in which the application is defined
4. New or updated status, which is to be one of:
current: The application is in current use
deprecated: The application is in current use but its use is
discouraged
Borenstein & Kucherawy Expires May 23, 2013 [Page 9]
Internet-Draft Reputation Media Type November 2012
historic: The application is no longer in current use
5. A description of the subject of a query within this reputation,
and a legal syntax for the same
6. An optional table of query parameters that are specific to this
application; each table entry must include:
Name: Name of the query parameter
Status: (as above)
Description: A short description of the purpose of this
parameter
Syntax: A reference to a description of valid syntax for the
parameter's value
Required: "yes" if the parameter is mandatory, "no" otherwise
7. A list of one or more assertions registered within this
application; each table entry is to include:
Name: Name of the assertion
Description: A short description of the assertion, with specific
meanings for values of 0.0 and 1.0
Scale: A short description of the scale used in computing the
value (see Section 4 of this document)
8. An optional list of one or more response set extension keys for
use within this application; each table entry is to include:
Name: Name of the extension key
Description: A short description of the key's intended meaning
Syntax: A description of valid values that can appear associated
with the key
6. Security Considerations
This document is primarily an IANA action registering a media type.
It does not describe a new protocol that might introduce security
considerations.
Borenstein & Kucherawy Expires May 23, 2013 [Page 10]
Internet-Draft Reputation Media Type November 2012
Discussion of the security and operational impacts of using
reputation services in general can be found throughout
[I-D.REPUTE-CONSIDERATIONS].
7. References
7.1. Normative References
[I-D.REPUTE-MODEL]
Borenstein, N. and M. Kucherawy, "A Model for Reputation
Interchange", draft-ietf-repute-model (work in progress),
November 2012.
[I-D.REPUTE-QUERY-HTTP]
Borenstein, N. and M. Kucherawy, "Reputation Data
Interchange using HTTP and XML",
draft-ietf-repute-query-http (work in progress),
November 2012.
[JSON] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627, July 2006.
[KEYWORDS]
Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
7.2. Informative References
[DKIM] Crocker, D., Ed., Hansen, T., Ed., and M. Kucherawy, Ed.,
"DomainKeys Identified Mail (DKIM) Signatures", RFC 6376,
September 2011.
[HTTP] 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.
[I-D.REPUTE-CONSIDERATIONS]
Kucherawy, M., "Operational Considerations Regarding
Reputation Services", draft-ietf-repute-model (work in
progress), November 2012.
[I-D.REPUTE-EMAIL-IDENTIFIERS]
Borenstein, N. and M. Kucherawy, "A Reputation Vocabulary
for Email Identifiers",
draft-ietf-repute-email-identifiers (work in progress),
November 2012.
Borenstein & Kucherawy Expires May 23, 2013 [Page 11]
Internet-Draft Reputation Media Type November 2012
[IANA-CONSIDERATIONS]
Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", RFC 5226, May 2008.
[MIME-REG]
Freed, N. and J. Klensin, "Media Type Specifications and
Registration Procedures", RFC 4288, December 2005.
Appendix A. Acknowledgments
The authors wish to acknowledge the contributions of the following to
this specification: Frank Ellermann, Tony Hansen, Jeff Hodges, John
Levine, David F. Skoll, and Mykyta Yevstifeyev.
Appendix B. Public Discussion
Public discussion of this suite of documents takes place on the
domainrep@ietf.org mailing list. See
https://www.ietf.org/mailman/listinfo/domainrep.
Authors' Addresses
Nathaniel Borenstein
Mimecast
203 Crescent St., Suite 303
Waltham, MA 02453
USA
Phone: +1 781 996 5340
Email: nsb@guppylake.com
Murray S. Kucherawy
2063 42nd Avenue
San Francisco, CA 94116
USA
Email: superuser@gmail.com
Borenstein & Kucherawy Expires May 23, 2013 [Page 12]
Html markup produced by rfcmarkup 1.129d, available from
https://tools.ietf.org/tools/rfcmarkup/