Identity Event Token
draft-hunt-idevent-token-00

Abstract

This specification defines an Identity Event token which may be distributed via a protocol such as HTTP. An identity event token is based on the JSON Web Token and may be optionally signed and/or encrypted. It describes a statement of fact that may be shared by an event publisher with registered subscribers.

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/.

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This Internet-Draft will expire on September 21, 2016.

Copyright Notice

Copyright (c) 2016 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.

Table of Contents

• 1. Introduction and Overview
• 1.1. Notational Conventions
• 1.2. Definitions
• 2. Events
• 2.1. Core Event Attributes
• 2.2. Event Token Construction
• 3. Security Considerations
• 4. IANA Considerations
• 4.1. Registration of Event URN Sub-namespace
• 4.2. Event Registry
• 5. References
• 5.1. Normative References
• 5.2. Informative References
• Appendix A. Contributors
• Appendix B. Acknowledgments
• Appendix C. Change Log
• Authors' Addresses

1. Introduction and Overview

This specification defines an extensible event token format which may be exchanged using protocols such as HTTP. The specification builds on the JSON Web Token format [RFC7519] in order to provide a self-contained message "token" that can be optionally signed using JSON Web Signature [RFC7515] and/or encrypted using JSON Web Encryption [RFC7516].

For the purpose of this specification an "event" is a statement of fact by a publisher (also known as an issuer) that the state of a resource it controls has changed in some way (explicitly or implicitly). Based on some agreed upon criteria for an event feed, the publisher distributes the event to the appropriate subscribers.

[[Background: to be removed from final specification]]At the time of writing of this specifications there are several discussions regarding the need for identity events. Some of these include:

• Events to allow SCIM resource co-ordination between SCIM domains.
• OAuth Token Revocation (see [RFC7009])
• OpenID Logout or downstream logout notification.
• Session Cancellation
• OpenID Risk Incident Sharing and Coordination (RISC) Events. See [RISC]
• The HEART WG [HEART] which intends to define privacy and security related events in health-related data sharing APIs.

This specification uses example SCIM events which are intended to be non-normative for the purpose of showing how an event may be used in practice.

A resource state change event typically includes explicit operation events such as: a resource has been created, modified, removed, or updated in some way.

In addition to explicit operations there may be higher-level statements made that describe an effect resulting from a change. For example, a publisher may wish to indicate that a user resource has taken over an email identifier that may have been used in the past. This cumulative event is a high-level statement that takes into account that another resource had a personal identifier that potentially conflicts with a newer resource. Because of the security impact, the publisher wishes to notify its subscribers of the identifier re-use. In this way, the event is not describing a particular state change to a resource, it describes a meta-conclusion based on its own business and security rules (this scenario is often called an 'account take-over' event).

A subscriber having received an event, validates and interprets the event and takes its own independent action, if any. For example, having been informed of a personal identifier now being associated with a different resource (i.e. is being used by someone-else), the subscriber may choose to ensure that the new user is not granted access to resources associated with the previous user.

Events SHOULD NOT be used to convey commands or requests. To do so requires complex bi-directional signalling and error recovery mechanisms which fall outside the scope of this specification. The intent of this specification is to define a way of exchanging historical statements of fact that subscribers may interpret for their own use.

This specification is scoped to security and identity related events. While event tokens may be used for other purposes, the specification only considers security and privacy concerns relevant to identity and personal information.

This specification may be optionally used with the identity event subscription management specification which provides the details of event feeds and how subscribers register for events(see [idevent-subscription]), defines a protocol registry for event transmission methods including transmission using HTTP.

1.1. 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 [RFC2119]. These keywords are capitalized when used to unambiguously specify requirements of the protocol or application features and behavior that affect the interoperability and security of implementations. When these words are not capitalized, they are meant in their natural-language sense.

For purposes of readability examples are not URL encoded. Implementers MUST percent encode URLs as described in Section 2.1 of [RFC3986].

Throughout this documents all figures MAY contain spaces and extra line-wrapping for readability and space limitations. Similarly, some URI's contained within examples, have been shortened for space and readability reasons.

1.2. Definitions

The following definitions are used with Identity Events:

Feed Publisher

The Feed Provider publishes events to be distributed to registered subscribers. In JWT terminology, the Feed Publisher is also known as the issuer iss).

Event

An event is a resource change statement that is to be distributed to one or more registered subscribers. An event is constructed as a JWT token and MAY be signed or encrypted using JWS/JWE for authentication and confidentiality reasons.

Feed

A feed is a URI that describes the set of resources and events under which events may be issued. An interested client registers with the Feed Provider to subscribe to events associated with a feed. When expressed in a JWT token, a feed is defined as the event's audience (aud).

Subscriber

A Subscriber registers to receive event notifications from a Feed Provider using a protocol such as HTTP.

2. Events

An identity event conveys a message (in the form of a JWT token [RFC7519]) about a resource (i.e. a security subject) that may be of interest to a subscriber or set of subscribers participating in an event feed (see [idevent-subscription]).

In addition to the JWT attributes iss and aud, an event message contains the attribute eventUris with at least one value containing the URI prefix urn:ietf:params:event:. The event URI values indicate what event information (attributes) and what type of event (e.g. resource modified) is contained in the event message. The definition of registered events are found in the event registry (see Section 4.2).

The attribute resourceUris specifies one or more affected resources which are the subject of the event.

The schema and structure of an event follows the JWT [RFC7519]. An event JWT has the following characteristics:

• a common set of attributes common to every event, and
• one or more event extensions that each contain a set of attributes that belonging to an extension.

{ 
  "jti": "3d0c3cf797584bd193bd0fb1bd4e7d30",
  "eventUris":[
    "urn:ietf:params:event:SCIM:password",
    "urn:ietf:params:event:extension:example.com:password"
  ],
  "iat": 1458496025,
  "iss": "https://scim.example.com",  
  "aud":[
    "https://jhub.example.com/Feeds/98d52461fa5bbc879593b7754",
    "https://jhub.example.com/Feeds/5d7604516b1d08641d7676ee7"
  ],  
  "sub": 
    "https://scim.example.com/Users/44f6142df96bd6ab61e7521d9",
  "urn:ietf:params:event:SCIM:password":{
    "id":"44f6142df96bd6ab61e7521d9",
  },
  "urn:ietf:params:event:extension:example.com:password":{
     "resetAttempts":5
  }
}

{  
  "jti": "4d3559ec67504aaba65d40b0363faad8",
  "eventUris":[
    "urn:ietf:params:event:SCIM:create"
  ],
  "iat": 1458496404,
  "iss": "https://scim.example.com",  
  "aud":[
   "https://scim.example.com/Feeds/98d52461fa5bbc879593b7754",
   "https://scim.example.com/Feeds/5d7604516b1d08641d7676ee7"
  ],  
  "sub": "https://scim.example.com/Users/44f6142df96bd6ab61e7521d9",
  "urn:ietf:params:event:SCIM:create":{
    "attributes":["id","name","userName","password","emails"],
    "values":{
      "emails":[
       {"type":"work","value":"jdoe@example.com"}
      ],
      "password":"not4u2no",
      "userName":"jdoe",
      "id":"44f6142df96bd6ab61e7521d9",
      "name":{
        "givenName":"John",
        "familyName":"Doe"
      }
    }  
  }
}

{"alg":"none"}

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