Security Events Working Group P. Hunt, Ed.
Internet-Draft Oracle
Intended status: Standards Track W. Denniss
Expires: January 1, 2018 Google
M. Ansari
M. Jones
June 30, 2017

Security Event Token (SET)


This specification defines the Security Event Token, which may be distributed via a protocol such as HTTP. The Security Event Token (SET) specification profiles the JSON Web Token (JWT), which can be optionally signed and/or encrypted. A SET describes a statement of fact from the perspective of an issuer that it intends to share with one or more receivers.

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

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This Internet-Draft will expire on January 1, 2018.

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Table of Contents

1. Introduction and Overview

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

This specification profiles the use of JWT for the purpose of issuing security event tokens (SETs). This specification defines a base format upon which profiling specifications define actual events and their meanings. Unless otherwise specified, this specification uses non-normative example events intended to demonstrate how events may be constructed.

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

Security Events are not commands issued between parties. A security event is a statement of fact from the perspective of an issuer about the state of a security subject (e.g., a web resource, token, IP address, the issuer itself) that the issuer controls or is aware of, that has changed in some way (explicitly or implicitly). A security subject MAY be permanent (e.g., a user account) or temporary (e.g., an HTTP session) in nature. A state change could describe a direct change of entity state, an implicit change of state or other higher-level security statements such as:

While subject state changes are often triggered by a user-agent or security-subsystem, the issuance and transmission of an event often occurs asynchronously and in a back-channel to the action which caused the change that generated the security event. Subsequently, an Event Receiver, having received a SET, validates and interprets the received SET and takes its own independent actions, if any. For example, having been informed of a personal identifier being associated with a different security subject (e.g., an email address is being used by someone else), the Event Receiver may choose to ensure that the new user is not granted access to resources associated with the previous user. Or, the Event Receiver may not have any relationship with the subject, and no action is taken.

While Event Receivers will often take actions upon receiving SETs, security events MUST NOT be assumed to be commands or requests. The intent of this specification is to define a way of exchanging statements of fact that subscribers may interpret for their own purposes. As such, SETs have no capability for error signaling other to ensure the validation of a received SET.

1.1. Notational Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "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 inter-operability 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.

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

1.2. Definitions

The following definitions are used with SETs:

Security Event Token (SET)

A SET is a JWT [RFC7519] that is distributed to one or more registered Event Receivers.
Event Transmitter

A service provider that delivers SETs to other providers known as Event Receivers.
Event Receiver

An Event Receiver is an entity that receives SETs through some distribution method.

A SET describes an event or state change that has occurred about a Subject. A Subject may be a principal (e.g., Section 4.1.2), a web resource, an entity such as an IP address, or the issuer itself that a SET might reference.
Profiling Specification
A specification that uses the SET Token specification to define one or more event types and the associated claims included.

2. The Security Event Token (SET)

A SET is a data structure (in the form of a JWT [RFC7519]) representing one or more related security events about a Subject.

The schema and structure of a SET follows the JWT [RFC7519] specification. A SET has the following structure:

The following is a non-normative example showing the JWT Claims Set for a hypothetical SCIM password reset SET. This example shows an additional events value ( used to convey additional information -- in this case, the current count of reset attempts:

  "jti": "3d0c3cf797584bd193bd0fb1bd4e7d30",
  "iat": 1458496025,
  "iss": "",  
  "aud": [
  "sub": "",
  "events": {
      { "id":"44f6142df96bd6ab61e7521d9"},
      { "resetAttempts":5}

Figure 1: Example SCIM Password Reset Event

The event in the figure above expresses hypothetical password reset event for SCIM [RFC7644]. The JWT consists of:

In this example, the SCIM event indicates that a password has been updated and the current password reset count is 5. Notice that the value for "resetAttempts" is actually part of its own JSON object associated with its own event URI attribute.

Here is another example JWT Claims Set for a security event token, this one for a Logout Token:

   "iss": "",
   "sub": "248289761001",
   "aud": "s6BhdRkqt3",
   "iat": 1471566154,
   "jti": "bWJq",
   "sid": "08a5019c-17e1-4977-8f42-65a12843ea02",
   "events": {
     "": {}

Figure 2: Example OpenID Back-Channel Logout Event

In the following example JWT Claims Set, a fictional medical service collects consent for medical actions and notifies other parties. The individual for whom consent is identified was originally authenticated via OpenID Connect. In this case, the issuer of the security event is an application rather than the OpenID provider:

  "jti": "fb4e75b5411e4e19b6c0fe87950f7749",
  "sub": "248289761001",
  "iat": 1458496025,
  "iss": "",  
  "aud": [
  "events": {

Figure 3: Example Consent Event

2.1. Core SET Claims

The following are claims that are based on [RFC7519] claim definitions and are profiled for use in an event token:


As defined by Section 4.1.7 contains a unique identifier for an event. The identifier SHOULD be unique within a particular event feed and MAY be used by clients to track whether a particular event has already been received. This claim is REQUIRED.

A single valued String containing the URI of the service provider publishing the SET (the issuer). This claim is REQUIRED. Note that when a SET is expressing an event about a Security Subject for which the SET issuer is not the issuer of the Security Subject, the conflict SHALL be resolved by including the Security Subject iss value within the event "payload" (see events claim).

The syntax of the claim is as defined in Section 4.1.3. This claim contains one or more audience identifiers for the SET. This claim is RECOMMENDED.

As defined by Section 4.1.6, a value containing a NumericDate, which represents when the event was issued. Unless otherwise specified, the value SHOULD be interpreted as equivalent to the actual time of the event. This claim is REQUIRED.

Defined by Section 4.1.5, a number whose value is a NumericDate. In the context of the SET token it SHALL be interpreted to mean a date in which the event is believed to have occurred (in the past) or will occur in the future. Note: there MAY be some cases where "nbf" is still smaller than "iat" such as when it took an extended time for a SET to be issued (for example after some analysis). This claim is OPTIONAL.
As defined by Section 4.1.2, a String or URI value representing the principal or the subject of the SET. This is usually the entity whose "state" was changed. For example, an IP Address was added to a black list. A URI representing a user resource that was modified. A token identifier for a revoked token. If used, the Profile Specification SHOULD define the content and format semantics for the value. This claim is OPTIONAL, as the principal for any given profile may already be identified without the inclusion of a subject claim. Note that some SET profiles MAY choose to convey event subject information in the event payload, particularly if the subject information is relative to issuer information that is also conveyed in the event payload, which may be the case for some identity SET profiles.
As defined by [RFC7519], this claim is time on which the JWT MUST NOT be accepted for processing. In the context of a SET however, this notion does not apply since a SET reflects something that has already been processed and is historical in nature. While some specifications MAY have a need for this claim, its use in general cases is NOT RECOMMENDED.

The following are new claims defined by this specification:


The semantics of this claim is to define a set of event statements that each MAY add additional claims to fully describe a single logical event that has occurred (e.g. a state change to a subject). Multiple event statements of the same type SHALL NOT be accepted. The events claim SHOULD NOT be used to express multiple logical events.
The value of events is a JSON object whose members are a set of JSON name/value pairs whose names are URIs representing the event statements being expressed. Event URI values SHOULD be stable values (e.g. a permanent URL for an event specification). For each name present, the corresponding value SHALL be a JSON object. The JSON object MAY be an empty object ({}), or it MAY be a JSON object containing data as described by the Profiling Specification.

An OPTIONAL String value that represents a unique transaction identifier. In cases where multiple SETs are issued based on different event URIs, the transaction identifier MAY be used to correlate SETs to the same originating event or stateful change.

2.2. Explicit Typing of SETs

This specification registers the application/secevent+jwt media type, which can be used to indicate that the content is a SET. SETs MAY include this media type in the typ header parameter of the JWT representing the SET to explicitly declare that the JWT is a SET. This MUST be included if the SET could be used in an application context in which it could be confused with other kinds of JWTs.

Per the definition of typ in Section 4.1.9 of [RFC7515], it is RECOMMENDED that the "application/" prefix be omitted. Therefore, the typ value used SHOULD be secevent+jwt.

2.3. Security Event Token Construction

A SET is a JWT [RFC7519] that is constructed by building a JSON structure that constitutes an event object which is then used as the body of a JWT.

While this specification uses JWT to convey a SET, implementers SHALL NOT use SETs to convey authentication or authorization assertions.

The following is an example JWT Claims Set for a security event token (which has been formatted for readability):

  "jti": "4d3559ec67504aaba65d40b0363faad8",
  "iat": 1458496404,
  "iss": "",  
  "aud": [
  "events": {
    "urn:ietf:params:scim:event:create": {
      "attributes":["id", "name", "userName", "password", "emails"]

Figure 4: Example Event Claims

When transmitted, the above JSON body must be converted into a JWT as per [RFC7519].

The following is an example of a SCIM Event expressed as an unsecured JWT. The JOSE Header is:


Base64url encoding of the octets of the UTF-8 representation of the JOSE Header yields:


The example JWT Claims Set is encoded as follows:


The encoded JWS signature is the empty string. Concatenating the parts yields:


Figure 5: Example Unsecured Security Event Token

For the purpose of a simpler example in Figure 5, an unsecured token was shown. When SETs are not signed or encrypted, the Event Receiver MUST employ other mechanisms such as TLS and HTTP to provide integrity, confidentiality, and issuer validation, as needed by the application.

When validation (i.e. auditing), or additional transmission security is required, JWS signing and/or JWE encryption MAY be used. To create and or validate a signed and/or encrypted SET, follow the instructions in Section 7 of [RFC7519].

3. Requirements for SET Profiles

Profile Specifications for SETs define the syntax and semantics of SETs conforming to that SET profile and rules for validating those SETs. The syntax defined by profiling specifications includes what claims and event payload values are used by SETs utilizing the profile.

Defining the semantics of the SET contents for SETs utilizing the profile is equally important. Possibly most important is defining the procedures used to validate the SET issuer and to obtain the keys controlled by the issuer that were used for cryptographic operations used in the JWT representing the SET. For instance, some profiles may define an algorithm for retrieving the SET issuer's keys that uses the iss claim value as its input.

Profile Specifications MUST clearly specify the steps that a recipient of a SET utilizing that profile MUST perform to validate that the SET is both syntactically and semantically valid.

4. Security Considerations

4.1. Confidentiality and Integrity

SETs may often contain sensitive information. Therefore, methods for distribution of events SHOULD require the use of a transport-layer security mechanism when distributing events. Parties MUST support TLS 1.2 [RFC5246] and MAY support additional transport-layer mechanisms meeting its security requirements. When using TLS, the client MUST perform a TLS/SSL server certificate check, per [RFC6125]. Implementation security considerations for TLS can be found in "Recommendations for Secure Use of TLS and DTLS" [RFC7525].

Security Events distributed through third-parties or that carry personally identifiable information, SHOULD be encrypted using JWE [RFC7516] or secured for confidentiality by other means.

Security Events distributed without authentication over the channel, such as via TLS ([RFC5246] and [RFC6125]), and/or OAuth 2.0 [RFC6749], or Basic Authentication [RFC7617], MUST be signed using JWS [RFC7515] so that individual events can be authenticated and validated by the Event Receiver.

4.2. Delivery

This specification does not define a delivery mechanism by itself. In addition to confidentiality and integrity (discussed above), implementers and Profile Specifications MUST consider the consequences of delivery mechanisms that are not secure and/or not assured. For example, while a SET may be end-to-end secured using JWE encrypted SETs, without TLS there is no assurance that the correct endpoint received the SET and that it could be successfully processed.

4.3. Sequencing

As defined in this specification, there is no defined way to order multiple SETs in a sequence. Depending on the type and nature of SET event, order may or may not matter. For example, in provisioning, event order is critical -- an object could not be modified before it was created. In other SET types, such as a token revocation, the order of SETs for revoked tokens does not matter. If however, the event was described as a log-in or logged-out status for a user subject, then order becomes important.

Profiling Specifications and implementers SHOULD take caution when using timestamps such as iat to define order. Distributed systems will have some amount of clock-skew and thus time by itself will not guarantee order.

Specifications profiling SET SHOULD define a mechanism for detecting order or sequence of events. For example, the txn claim could contain an ordered value (e.g., a counter) that the issuer defines.

4.4. Timing Issues

When SETs are delivered asynchronously and/or out-of-band with respect to the original action that incurred the security event, it is important to consider that a SET might be delivered to a Subscriber in advance or well behind the process that caused the event. For example, a user having been required to logout and then log back in again, may cause a logout SET to be issued that may arrive at the same time as the user-agent accesses a web site having just logged-in. If timing is not handled properly, the effect would be to erroneously treat the new user session as logged out. Profiling Specifications SHOULD be careful to anticipate timing and subject selection information. For example, it might be more appropriate to cancel a "session" rather than a "user". Alternatively, the specification could use timestamps that allows new sessions to be started immediately after a stated logout event time.

4.5. Distinguishing SETs from ID Tokens

Because [RFC7519] states that "all claims that are not understood by implementations MUST be ignored", there is a consideration that a SET token might be confused with ID Token [OpenID.Core] if a SET is mistakenly or intentionally used in a context requiring an ID Token. If a SET could otherwise be interpreted as a valid ID Token (because it includes the required claims for an ID Token and valid issuer and audience claim values for an ID Token) then that SET profile MUST require that the exp claim not be present in the SET. Because exp is a required claim in ID Tokens, valid ID Token implementations will reject such a SET if presented as if it were an ID Token.

Excluding exp from SETs that could otherwise be confused with ID Tokens is actually defense in depth. In any OpenID Connect contexts in which an attacker could attempt to substitute a SET for an ID Token, the SET would actually already be rejected as an ID Token because it would not contain the correct nonce claim value for the ID Token to be accepted in that context.

Note that the use of explicit typing, as described in Section 2.2, will not achieve disambiguation between ID Tokens and SETs, as the ID Token validation rules do not use the typ header parameter value.

4.6. Distinguishing SETs from Access Tokens

OAuth 2.0 [RFC6749] defines access tokens as being opaque. Nonetheless, some implementations implement access tokens as JWTs. Because the structure of these JWTs is implementation-specific, ensuring that a SET cannot be confused with such an access token is therefore likewise, in general, implementation specific. Nonetheless, it is recommended that SET profiles employ the following strategies to prevent possible substitutions of SETs for access tokens in contexts in which that might be possible:

4.7. Distinguishing SETs from other kinds of JWTs

JWTs are now being used in application areas beyond the identity applications in which they first appeared. For instance, the Session Initiation Protocol (SIP) Via Header Field [RFC8055] and Personal Assertion Token (PASSporT) [I-D.ietf-stir-passport] specifications both define JWT profiles that use mostly or completely different sets of claims than are used by ID Tokens. If it would otherwise be possible for an attacker to substitute a SET for one of these (or other) kinds of JWTs, then the SET profile must be defined in such a way that any substituted SET will result in its rejection when validated as the intended kind of JWT.

The most direct way to ensure that a SET is not confused with another kind of JWT is to have the JWT validation logic reject JWTs containing an events claim unless the JWT is intended to be a SET. This approach can be employed for new systems but may not be applicable to existing systems.

Another direct way to prevent confusion is to employ explicit typing, as described in Section 2.2, and modify applicable token validation systems to use the typ header parameter value. This approach can be employed for new systems but may not be applicable to existing systems.

For many use cases, the simplest way to prevent substitution is requiring that the SET not include claims that are required for the kind of JWT that might be the target of an attack. For example, for [RFC8055], the sip_callid claim could be omitted and for [I-D.ietf-stir-passport], the orig claim could be omitted.

In many contexts, simple measures such as these will accomplish the task, should confusion otherwise even be possible. Note that this topic is being explored in a more general fashion in JSON Web Token Best Current Practices [I-D.sheffer-oauth-jwt-bcp]. The proposed best practices in that draft may also be applicable for particular SET profiles and use cases.

5. Privacy Considerations

If a SET needs to be retained for audit purposes, JWS MAY be used to provide verification of its authenticity.

Event Transmitters SHOULD attempt to specialize feeds so that the content is targeted to the specific business and protocol needs of subscribers.

When sharing personally identifiable information or information that is otherwise considered confidential to affected users, Event Transmitters and Receivers MUST have the appropriate legal agreements and user consent or terms of service in place.

The propagation of subject identifiers can be perceived as personally identifiable information. Where possible, Event Transmitters and Receivers SHOULD devise approaches that prevent propagation -- for example, the passing of a hash value that requires the subscriber to already know the subject.

6. IANA Considerations

6.1. JSON Web Token Claims Registration

This specification registers the events and txn claims in the IANA "JSON Web Token Claims" registry [IANA.JWT.Claims] established by [RFC7519].

6.1.1. Registry Contents

6.2. Media Type Registration

6.2.1. Registry Contents

This section registers the application/secevent+jwt media type [RFC2046] in the "Media Types" registry [IANA.MediaTypes] in the manner described in [RFC6838], which can be used to indicate that the content is a SET.

7. References

7.1. Normative References

[IANA.JWT.Claims] IANA, "JSON Web Token Claims"
[IANA.MediaTypes] IANA, "Media Types"
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC3986] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, January 2005.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and Verification of Domain-Based Application Service Identity within Internet Public Key Infrastructure Using X.509 (PKIX) Certificates in the Context of Transport Layer Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March 2011.
[RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, October 2012.
[RFC7519] Jones, M., Bradley, J. and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015.
[RFC7525] Sheffer, Y., Holz, R. and P. Saint-Andre, "Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 2015.
[RFC7617] Reschke, J., "The 'Basic' HTTP Authentication Scheme", RFC 7617, DOI 10.17487/RFC7617, September 2015.

7.2. Informative References

[I-D.ietf-stir-passport] Wendt, C. and J. Peterson, "Personal Assertion Token (PASSporT)", Internet-Draft draft-ietf-stir-passport-11, February 2017.
[I-D.sheffer-oauth-jwt-bcp] Sheffer, Y., Hardt, D. and M. Jones, "JSON Web Token Best Current Practices", Internet-Draft draft-sheffer-oauth-jwt-bcp-00, June 2017.
[OpenID.Core] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B. and C. Mortimore, "OpenID Connect Core 1.0", November 2014.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, DOI 10.17487/RFC2046, November 1996.
[RFC6838] Freed, N., Klensin, J. and T. Hansen, "Media Type Specifications and Registration Procedures", BCP 13, RFC 6838, DOI 10.17487/RFC6838, January 2013.
[RFC7009] Lodderstedt, T., Dronia, S. and M. Scurtescu, "OAuth 2.0 Token Revocation", RFC 7009, DOI 10.17487/RFC7009, August 2013.
[RFC7515] Jones, M., Bradley, J. and N. Sakimura, "JSON Web Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May 2015.
[RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)", RFC 7516, DOI 10.17487/RFC7516, May 2015.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517, DOI 10.17487/RFC7517, May 2015.
[RFC7644] Hunt, P., Grizzle, K., Ansari, M., Wahlstroem, E. and C. Mortimore, "System for Cross-domain Identity Management: Protocol", RFC 7644, DOI 10.17487/RFC7644, September 2015.
[RFC8055] Holmberg, C. and Y. Jiang, "Session Initiation Protocol (SIP) Via Header Field Parameter to Indicate Received Realm", RFC 8055, DOI 10.17487/RFC8055, January 2017.
[saml-core-2.0] Internet2, "Assertions and Protocols for the OASIS Security Assertion Markup Language (SAML) V2.0", March 2005.

Appendix A. Acknowledgments

The editors would like to thank the members of the IETF SCIM working group, which began discussions of provisioning events starting with draft-hunt-scim-notify-00 in 2015.

The editors would like to thank the participants in the IETF id-event mailing list and related working groups for their support of this specification.

Appendix B. Change Log

From the original draft-hunt-idevent-token:

Draft 01 - PH - Renamed eventUris to events

Draft 00 - PH - First Draft

Draft 01 - PH - Fixed some alignment issues with JWT. Remove event type attribute.

Draft 02 - PH - Renamed to Security Events, removed questions, clarified examples and intro text, and added security and privacy section.

Draft 03 - PH events claim, and proof-reading corrections.

- mbj - Registered

Draft 04 - PH -

Draft 05 - PH - Fixed find/replace error that resulted in claim being spelled claimc

Draft 06 - PH -

Draft 07 -

Draft 08 - PH -

From draft-ietf-secevent-token:

Draft 00 - PH - First WG Draft based on draft-hunt-idevent-token

Draft 01 - PH - Changes as follows:

Draft 02 - Changes are as follows:

Authors' Addresses

Phil Hunt (editor) Oracle Corporation EMail:
William Denniss Google EMail:
Morteza Ansari Cisco EMail:
Michael B. Jones Microsoft EMail: URI: