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Versions: 00 01 02 03

Security Events Working Group                            A. Backman, Ed.
Internet-Draft                                                    Amazon
Intended status: Standards Track                           M. Jones, Ed.
Expires: April 21, 2019                                        Microsoft
                                                            M. Scurtescu
                                                                Coinbase
                                                               M. Ansari
                                                                   Cisco
                                                              A. Nadalin
                                                               Microsoft
                                                        October 18, 2018


       Push-Based Security Event Token (SET) Delivery Using HTTP
                    draft-ietf-secevent-http-push-03

Abstract

   This specification defines how a Security Event Token (SET) may be
   delivered to an intended recipient using HTTP POST.  The SET is
   transmitted in the body of an HTTP POST reqest to an endpoint
   operated by the recipient, and the recipient indicates successful or
   failed transmission via the HTTP response.

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 https://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 April 21, 2019.

Copyright Notice

   Copyright (c) 2018 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



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   (https://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 . . . . . . . . . . . . . . . . . .   2
     1.1.  Notational Conventions  . . . . . . . . . . . . . . . . .   3
     1.2.  Definitions . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  SET Delivery  . . . . . . . . . . . . . . . . . . . . . . . .   3
     2.1.  Transmitting a SET  . . . . . . . . . . . . . . . . . . .   4
     2.2.  Success Response  . . . . . . . . . . . . . . . . . . . .   5
     2.3.  Failure Response  . . . . . . . . . . . . . . . . . . . .   6
     2.4.  Security Event Token Delivery Error Codes . . . . . . . .   6
   3.  Authentication and Authorization  . . . . . . . . . . . . . .   7
   4.  Delivery Reliability  . . . . . . . . . . . . . . . . . . . .   7
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   8
     5.1.  Authentication Using Signed SETs  . . . . . . . . . . . .   8
     5.2.  TLS Support Considerations  . . . . . . . . . . . . . . .   8
     5.3.  Denial of Service . . . . . . . . . . . . . . . . . . . .   8
     5.4.  Authenticating Persisted SETs . . . . . . . . . . . . . .   8
   6.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .   9
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
     7.1.  Security Event Token Delivery Error Codes . . . . . . . .   9
       7.1.1.  Registration Template . . . . . . . . . . . . . . . .   9
       7.1.2.  Initial Registry Contents . . . . . . . . . . . . . .  10
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  13
   Appendix A.  Other Streaming Specifications . . . . . . . . . . .  13
   Appendix B.  Acknowledgments  . . . . . . . . . . . . . . . . . .  15
   Appendix C.  Change Log . . . . . . . . . . . . . . . . . . . . .  15
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  17

1.  Introduction and Overview

   This specification defines a mechanism by which a transmitter of a
   Security Event Token (SET) [RFC8417] may deliver the SET to an
   intended recipient via HTTP POST [RFC7231].

   Push-Based SET Delivery over HTTP POST is intended for scenarios
   where all of the following apply:





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   o  The transmitter of the SET is capable of making outbound HTTP
      requests.

   o  The recipient is capable of hosting an HTTP endpoint that is
      accessible to the transmitter.

   o  The transmitter and recipient are known to one another.

   o  The transmitter and recipient have an out-of-band mechanism for
      exchanging configuration metadata such as endpoint URLs and
      cryptographic key parameters.

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 BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   Throughout this documents all figures may contain spaces and extra
   line-wrapping for readability and due to space limitations.

1.2.  Definitions

   This specification utilizes terminology defined in [RFC8417], as well
   as the terms defined below:

   SET Transmitter
      An entity that delivers SETs in its possession to one or more SET
      Recipients.

2.  SET Delivery

   To deliver a SET to a given SET Recipient, the SET Transmitter makes
   a SET Transmission Request to the SET Recipient, with the SET itself
   contained within the request.  The SET Recipient replies to this
   request with a response either acknowledging successful transmission
   of the SET, or indicating that an error occurred while receiving,
   parsing, and/or validating the SET.

   Upon receipt of a SET, the SET Recipient SHALL validate that all of
   the following are true:

   o  The SET Recipient can parse the SET.

   o  The SET is authentic (i.e., it was issued by the issuer specified
      within the SET).



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   o  The SET Recipient is identified as an intended audience of the
      SET.

   The mechanisms by which the SET Recipient performs this validation
   are out of scope for this document.  SET parsing and issuer and
   audience identification are defined in [RFC8417].  The mechanism for
   validating the authenticity of a SET is implementation specific, and
   may vary depending on the authentication mechanisms in use, and
   whether the SET is signed and/or encrypted (See Section 3).

   The SET Recipient SHOULD ensure that the SET is persisted in a way
   that is sufficient to meet the SET Recipient's own reliability
   requirements, and MUST NOT expect or depend on a SET Transmitter to
   re-transmit or otherwise make available to the SET Recipient a SET
   once the SET Recipient acknowledges that it was received
   successfully.

   Once the SET has been validated and persisted, the SET Recipient
   SHOULD immediately return a response indicating that the SET was
   successfully delivered.  The SET Recipient SHOULD NOT perform
   extensive business logic that processes the event expressed by the
   SET prior to sending this response.  Such logic SHOULD be executed
   asynchronously from delivery, in order to minimize the expense and
   impact of SET delivery on the SET Transmitter.

   The SET Transmitter SHOULD NOT re-transmit a SET, unless the response
   from the SET Recipient in previous transmissions indicated a
   potentially recoverable error (such as server unavailability that may
   be transient, or a decryption failure that may be due to
   misconfigured keys on the SET Recipient's side).  In the latter case,
   the SET Transmitter MAY re-transmit a SET, after an appropriate delay
   to avoid overwhelming the SET Recipient (see Section 4).

2.1.  Transmitting a SET

   To transmit a SET to a SET Recipient, the SET Transmitter makes an
   HTTP POST request to an HTTP endpoint provided by the SET Recipient.
   The "Content-Type" header of this request MUST be "application/
   secevent+jwt" as defined in Sections 2.2 and 6.2 of [RFC8417], and
   the "Accept" header MUST be "application/json".  The request body
   MUST consist of the SET itself, represented as a JWT [RFC7519].

   The mechanisms by which the SET Transmitter determines the HTTP
   endpoint to use when transmitting a SET to a given SET Recipient are
   not defined by this specification and may be implementation-specific.






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   The following is a non-normative example of a SET transmission
   request:

   POST /Events  HTTP/1.1
   Host: notify.rp.example.com
   Accept: application/json
   Content-Type: application/secevent+jwt

   eyJhbGciOiJub25lIn0
   .
   eyJwdWJsaXNoZXJVcmkiOiJodHRwczovL3NjaW0uZXhhbXBsZS5jb20iLCJmZWV
   kVXJpcyI6WyJodHRwczovL2podWIuZXhhbXBsZS5jb20vRmVlZHMvOThkNTI0Nj
   FmYTViYmM4Nzk1OTNiNzc1NCIsImh0dHBzOi8vamh1Yi5leGFtcGxlLmNvbS9GZ
   WVkcy81ZDc2MDQ1MTZiMWQwODY0MWQ3Njc2ZWU3Il0sInJlc291cmNlVXJpcyI6
   WyJodHRwczovL3NjaW0uZXhhbXBsZS5jb20vVXNlcnMvNDRmNjE0MmRmOTZiZDZ
   hYjYxZTc1MjFkOSJdLCJldmVudFR5cGVzIjpbIkNSRUFURSJdLCJhdHRyaWJ1dG
   VzIjpbImlkIiwibmFtZSIsInVzZXJOYW1lIiwicGFzc3dvcmQiLCJlbWFpbHMiX
   SwidmFsdWVzIjp7ImVtYWlscyI6W3sidHlwZSI6IndvcmsiLCJ2YWx1ZSI6Impk
   b2VAZXhhbXBsZS5jb20ifV0sInBhc3N3b3JkIjoibm90NHUybm8iLCJ1c2VyTmF
   tZSI6Impkb2UiLCJpZCI6IjQ0ZjYxNDJkZjk2YmQ2YWI2MWU3NTIxZDkiLCJuYW
   1lIjp7ImdpdmVuTmFtZSI6IkpvaG4iLCJmYW1pbHlOYW1lIjoiRG9lIn19fQ
   .

                Figure 1: Example SET Transmission Request

2.2.  Success Response

   If the SET is determined to be valid, the SET Recipient SHALL
   "acknowledge" successful transmission by responding with HTTP
   Response Status Code 202 (Accepted) (see Section 6.3.3 of [RFC7231]).
   The body of the response MUST be empty.

   The following is a non-normative example of a successful receipt of a
   SET.

   HTTP/1.1 202 Accepted

              Figure 2: Example Successful Delivery Response

   Note that the purpose of the "acknowledgement" response is to let the
   SET Transmitter know that a SET has been delivered and the
   information no longer needs to be retained by the SET Transmitter.
   Before acknowledgement, SET Recipients SHOULD ensure they have
   validated received SETs and retained them in a manner appropriate to
   information retention requirements appropriate to the SET event types
   signaled.  The level and method of retention of SETs by SET
   Recipients is out of scope of this specification.




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2.3.  Failure Response

   In the event of a general HTTP error condition, the SET Recipient MAY
   respond with an appropriate HTTP Status Code as defined in Section 6
   of [RFC7231].

   When the SET Recipient detects an error parsing or validating a SET
   transmitted in a SET Transmission Request, the SET Recipient SHALL
   respond with an HTTP Response Status Code of 400 (Bad Request).  The
   "Content-Type" header of this response MUST be "application/json",
   and the body MUST be a JSON object containing the following name/
   value pairs:

   err  A Security Event Token Error Code (see Section 2.4).

   description  Human-readable text that describes the error and MAY
      contain additional diagnostic information.

   The following is an example non-normative error response.

   HTTP/1.1 400 Bad Request
   Content-Type: application/json

   {
   "err":"dup",
   "description":"SET already received. Ignored."

   }

                     Figure 3: Example Error Response

2.4.  Security Event Token Delivery Error Codes

   Security Event Token Delivery Error Codes are strings that identify a
   specific type of error that may occur when parsing or validating a
   SET.  Every Security Event Token Delivery Error Code MUST have a
   unique name registered in the IANA "Security Event Token Delivery
   Error Codes" registry established by Section 7.1.

   The following table presents the initial set of Error Codes that are
   registered in the IANA "Security Event Token Delivery Error Codes"
   registry:









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   +-----------+-------------------------------------------------------+
   | Error     | Description                                           |
   | Code      |                                                       |
   +-----------+-------------------------------------------------------+
   | json      | Invalid JSON object.                                  |
   | jwtParse  | Invalid or unparsable JWT or JSON structure.          |
   | jwtHdr    | An invalid JWT header was detected.                   |
   | jwtCrypto | Unable to parse due to unsupported algorithm.         |
   | jws       | Signature was not validated.                          |
   | jwe       | Unable to decrypt JWE encoded data.                   |
   | jwtAud    | Invalid audience value.                               |
   | jwtIss    | Issuer not recognized.                                |
   | setType   | An unexpected Event type was received.                |
   | setParse  | Invalid structure was encountered such as an          |
   |           | inability to parse or an incomplete set of Event      |
   |           | claims.                                               |
   | setData   | SET claims incomplete or invalid.                     |
   | dup       | A duplicate SET was received and has been ignored.    |
   +-----------+-------------------------------------------------------+

                     Table 1: SET Delivery Error Codes

3.  Authentication and Authorization

   The SET delivery method described in this specification is based upon
   HTTP and depends on the use of TLS and/or standard HTTP
   authentication and authorization schemes as per [RFC7235].

   Because SET Delivery describes a simple function, authorization for
   the ability to pick-up or deliver SETs can be derived by considering
   the identity of the SET issuer, or via other employed authentication
   methods.  Because SETs are not commands, SET Recipients are free to
   ignore SETs that are not of interest.

4.  Delivery Reliability

   Delivery reliability requirements may vary from implementation to
   implementation.  This specification defines the response from the SET
   Recipient in such a way as to provide the SET Transmitter with the
   information necessary to determine what further action is required,
   if any, in order to meet their requirements.  SET Transmitters with
   high reliability requirements may be tempted to always retry failed
   transmissions, however it should be noted that for many types of SET
   delivery errors, a retry is extremely unlikely to be successful.  For
   example, "json", "jwtParse", and "setParse" all indicate structural
   errors in the content of the SET that are likely to remain when re-
   transmitting the same SET.  Others such as "jws" or "jwe" may be




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   transient, for example if cryptographic material has not been
   properly distributed to the SET Recipient's systems.

   Implementers SHOULD evaluate their reliability requirements and the
   impact of various retry mechanisms on the performance of their
   systems to determine the correct strategy for various error
   conditions.

5.  Security Considerations

5.1.  Authentication Using Signed SETs

   In scenarios where HTTP authorization or TLS mutual authentication
   are not used or are considered weak, JWS signed SETs SHOULD be used
   (see [RFC7515] and Security Considerations [RFC8417]).  This enables
   the SET Recipient to validate that the SET issuer is authorized to
   deliver the SET.

5.2.  TLS Support Considerations

   SETs may contain sensitive information that is considered PII (e.g.,
   subject claims).  In such cases, SET Transmitters and SET Recipients
   MUST require the use of a transport-layer security mechanism.  Event
   delivery endpoints 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].

5.3.  Denial of Service

   The SET Recipient may be vulnerable to a denial-of-service attack
   where a malicious party makes a high volume of requests containing
   invalid SETs, causing the endpoint to expend significant resources on
   cryptographic operations that are bound to fail.  This may be
   mitigated by authenticating SET Transmitters with a mechanism with
   low runtime overhead, such as mutual TLS.

5.4.  Authenticating Persisted SETs

   At the time of receipt, the SET Recipient can rely upon transport
   layer mechanisms, HTTP authentication methods, and/or other context
   from the transmission request to authenticate the SET Transmitter and
   validate the authenticity of the SET.  However, this context is
   typically unavailable to systems that the SET Recipient forwards the
   SET onto, or to systems that retrieve the SET from storage.  If the
   SET Recipient requires the ability to validate SET authenticity



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   outside of the context of the transmission request, then the SET
   Transmitter SHOULD sign the SET in accordance with [RFC7515] and
   optionally also encrypt it in accordance with [RFC7516].

6.  Privacy Considerations

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

   When sharing personally identifiable information or information that
   is otherwise considered confidential to affected users, SET
   Transmitters and Recipients 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, SET Transmitters and
   Recipients SHOULD devise approaches that prevent propagation -- for
   example, the passing of a hash value that requires the subscriber to
   already know the subject.

7.  IANA Considerations

7.1.  Security Event Token Delivery Error Codes

   This document defines Security Event Token Delivery Error Codes, for
   which IANA is asked to create and maintain a new registry titled
   "Security Event Token Delivery Error Codes".  Initial values for the
   Security Event Token Delivery Error Codes registry are given in
   Table 1.  Future assignments are to be made through the Expert Review
   registration policy ([RFC8126]) and shall follow the template
   presented in Section 7.1.1.

7.1.1.  Registration Template

   Error Code
      The name of the Security Event Token Delivery Error Code, as
      described in Section 2.4.  The name MUST be a case-sensitive ASCII
      string consisting only of upper-case letters ("A" - "Z"), lower-
      case letters ("a" - "z"), and digits ("0" - "9").

   Description
      A brief human-readable description of the Security Event Token
      Delivery Error Code.

   Change Controller
      For error codes registered by the IETF or its working groups, list
      "IETF Secevent Working Group".  For all other error codes, list
      the name of the party responsible for the registration.  Contact



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      information such as mailing address, email address, or phone
      number may also be provided.

   Defining Document(s)
      A reference to the document or documents that define the Security
      Event Token Delivery Error Code.  The definition MUST specify the
      name and description of the error code, and explain under what
      circumstances the error code may be used.  URIs that can be used
      to retrieve copies of each document at no cost SHOULD be included.

7.1.2.  Initial Registry Contents

      Error Code: json
      Description: Invalid JSON object
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: jwtParse
      Description: Invalid or unparsable JWT or JSON structure
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: jwtHdr
      Description: An invalid JWT header was detected
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: jwtCrypto
      Description: Unable to parse due to unsupported algorithm
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: jws
      Description: Signature was not validated
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: jwe
      Description: Unable to decrypt JWE encoded data
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: jwtAud
      Description: Invalid audience value
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: jwtIss



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      Description: Issuer not recognized
      Change Controller:
      Defining Document(s): Section 2.4 of this document

      Error Code: setType
      Description: An unexpected Event type was received
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: setParse
      Description: Invalid structure was encountered such as an
      inability to parse or an incomplete set of Event claims.
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: setData
      Description: SET claims incomplete or invalid
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

      Error Code: dup
      Description: A duplicate SET was received and has been ignored.
      Change Controller: IETF Secevent Working Group
      Defining Document(s): Section 2.4 of this document

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [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,
              <https://www.rfc-editor.org/info/rfc3986>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

   [RFC5988]  Nottingham, M., "Web Linking", RFC 5988,
              DOI 10.17487/RFC5988, October 2010,
              <https://www.rfc-editor.org/info/rfc5988>.




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   [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, <https://www.rfc-editor.org/info/rfc6125>.

   [RFC7159]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
              2014, <https://www.rfc-editor.org/info/rfc7159>.

   [RFC7231]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
              DOI 10.17487/RFC7231, June 2014,
              <https://www.rfc-editor.org/info/rfc7231>.

   [RFC7515]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web
              Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
              2015, <https://www.rfc-editor.org/info/rfc7515>.

   [RFC7516]  Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
              RFC 7516, DOI 10.17487/RFC7516, May 2015,
              <https://www.rfc-editor.org/info/rfc7516>.

   [RFC7517]  Jones, M., "JSON Web Key (JWK)", RFC 7517,
              DOI 10.17487/RFC7517, May 2015,
              <https://www.rfc-editor.org/info/rfc7517>.

   [RFC7519]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
              (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
              <https://www.rfc-editor.org/info/rfc7519>.

   [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, <https://www.rfc-editor.org/info/rfc7525>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.





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   [RFC8417]  Hunt, P., Ed., Jones, M., Denniss, W., and M. Ansari,
              "Security Event Token (SET)", RFC 8417,
              DOI 10.17487/RFC8417, July 2018,
              <https://www.rfc-editor.org/info/rfc8417>.

8.2.  Informative References

   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
              <https://www.rfc-editor.org/info/rfc3339>.

   [RFC6749]  Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
              RFC 6749, DOI 10.17487/RFC6749, October 2012,
              <https://www.rfc-editor.org/info/rfc6749>.

   [RFC6750]  Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
              Framework: Bearer Token Usage", RFC 6750,
              DOI 10.17487/RFC6750, October 2012,
              <https://www.rfc-editor.org/info/rfc6750>.

   [RFC7230]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Message Syntax and Routing",
              RFC 7230, DOI 10.17487/RFC7230, June 2014,
              <https://www.rfc-editor.org/info/rfc7230>.

   [RFC7235]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Authentication", RFC 7235,
              DOI 10.17487/RFC7235, June 2014,
              <https://www.rfc-editor.org/info/rfc7235>.

   [RFC7521]  Campbell, B., Mortimore, C., Jones, M., and Y. Goland,
              "Assertion Framework for OAuth 2.0 Client Authentication
              and Authorization Grants", RFC 7521, DOI 10.17487/RFC7521,
              May 2015, <https://www.rfc-editor.org/info/rfc7521>.

   [RFC7617]  Reschke, J., "The 'Basic' HTTP Authentication Scheme",
              RFC 7617, DOI 10.17487/RFC7617, September 2015,
              <https://www.rfc-editor.org/info/rfc7617>.

Appendix A.  Other Streaming Specifications

   [[EDITORS NOTE: This section to be removed prior to publication]]

   The following pub/sub, queuing, streaming systems were reviewed as
   possible solutions or as input to the current draft:

   XMPP Events




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   The WG considered the XMPP events ands its ability to provide a
   single messaging solution without the need for both polling and push
   modes.  The feeling was the size and methodology of XMPP was to far
   apart from the current capabilities of the SECEVENTs community which
   focuses in on HTTP based service delivery and authorization.

   Amazon Simple Notification Service

   Simple Notification Service, is a pub/sub messaging product from AWS.
   SNS supports a variety of subscriber types: HTTP/HTTPS endpoints, AWS
   Lambda functions, email addresses (as JSON or plain text), phone
   numbers (via SMS), and AWS SQS standard queues.  It doesn't directly
   support pull, but subscribers can get the pull model by creating an
   SQS queue and subscribing it to the topic.  Note that this puts the
   cost of pull support back onto the subscriber, just as it is in the
   push model.  It is not clear that one way is strictly better than the
   other; larger, sophisticated developers may be happy to own message
   persistence so they can have their own internal delivery guarantees.
   The long tail of OIDC clients may not care about that, or may fail to
   get it right.  Regardless, I think we can learn something from the
   Delivery Policies supported by SNS, as well as the delivery controls
   that SQS offers (e.g., Visibility Timeout, Dead-Letter Queues).  I'm
   not suggesting that we need all of these things in the spec, but they
   give an idea of what features people have found useful.

   Other information:

   o  API Reference:
      http://docs.aws.amazon.com/AWSSimpleQueueService/latest/
      APIReference/Welcome.html

   o  Visibility Timeouts:
      http://docs.aws.amazon.com/AWSSimpleQueueService/latest/
      SQSDeveloperGuide/sqs-visibility-timeout.html

   Apache Kafka

   Apache Kafka is an Apache open source project based upon TCP for
   distributed streaming.  It prescribes some interesting general
   purpose features that seem to extend far beyond the simpler streaming
   model SECEVENTs is after.  A comment from MS has been that Kafka does
   an acknowledge with poll combination event which seems to be a
   performance advantage.  See: https://kafka.apache.org/intro

   Google Pub/Sub






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   Google Pub Sub system favours a model whereby polling and
   acknowledgement of events is done as separate endpoints as separate
   functions.

   Information:

   o  Cloud Overview - https://cloud.google.com/pubsub/

   o  Subscriber Overview - https://cloud.google.com/pubsub/docs/
      subscriber

   o  Subscriber Pull(poll) - https://cloud.google.com/pubsub/docs/pull

Appendix B.  Acknowledgments

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

   The editors would like to thank Phil Hunt and the other authors of
   draft-ietf-secevent-delivery-02, on which this draft is based.

   The editors would like to thank the participants in the the SECEVENTS
   working group for their contributions to this specification.

Appendix C.  Change Log

   Draft 00 - AB - Based on draft-ietf-secevent-delivery-02 with the
   following changes:

   o  Renamed to "Push-Based SET Token Delivery Using HTTP"

   o  Removed references to the HTTP Polling delivery method.

   o  Removed informative reference to RFC6202.

   Draft 01 - AB:

   o  Fixed area and workgroup to match secevent.

   o  Removed unused definitions and definitions already covered by SET.

   o  Renamed Event Transmitter and Event Receiver to SET Transmitter
      and SET Receiver, respectively.

   o  Added IANA registry for SET Delivery Error Codes.

   o  Removed enumeration of HTTP authentication methods.



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   o  Removed generally applicable guidance for HTTP, authorization
      tokens, and bearer tokens.

   o  Moved guidance for using authentication methods as DoS protection
      to Security Considerations.

   o  Removed redundant instruction to use WWW-Authenticate header.

   o  Removed further generally applicable guidance for authorization
      tokens.

   o  Removed bearer token from example delivery request, and text
      referencing it.

   o  Broke delivery method description into separate request/response
      sections.

   o  Added missing empty line between headers and body in example
      request.

   o  Removed unapplicable notes about example formatting.

   o  Removed text about SET creation and handling.

   o  Removed duplication in protocol description.

   o  Added "non-normative example" text to example transmission
      request.

   o  Fixed inconsistencies in use of Error Code term.

   Draft 02 - AB:

   o  Rewrote abstract and introduction.

   o  Rewrote definitions for SET Transmitter, SET Receiver.

   o  Renamed Event Delivery section to SET Delivery.

   o  Readability edits to Success Response and Failure Response
      sections.

   o  Consolidated definition of error response under Failure Response
      section.

   o  Removed Event Delivery Process section and moved its content to
      parent section.




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   o  Readability edits to SET Delivery section and its subsections.

   o  Added callout that SET Receiver HTTP endpoint configuration is
      out-of-scope.

   o  Added callout that SET verification mechanisms are out-of-scope.

   o  Added retry guidance, notes regarding delivery reliability
      requirements.

   o  Added guidance around using JWS and/or JWE to authenticate
      persisted SETs.

   Draft 03 - mbj:

   o  Addressed problems identified in my 18-Jul-18 review message
      titled "Issues for both the Push and Poll Specs".

   o  Changes to align terminology with RFC 8417, for instance, by using
      the already defined term SET Recipient rather than SET Receiver.

   o  Applied editorial and minor normative corrections.

   o  Updated Marius' contact information.

Authors' Addresses

   Annabelle Backman (editor)
   Amazon

   Email: richanna@amazon.com


   Michael B. Jones (editor)
   Microsoft

   Email: mbj@microsoft.com
   URI:   http://self-issued.info/


   Marius Scurtescu
   Coinbase

   Email: marius.scurtescu@coinbase.com







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   Morteza Ansari
   Cisco

   Email: morteza.ansari@cisco.com


   Anthony Nadalin
   Microsoft

   Email: tonynad@microsoft.com









































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