Network Working Group                                    A. Backman, Ed.
Internet-Draft                                                    Amazon
Intended status: Standards Track                           M. Jones, Ed.
Expires: January 9, 2020                                       Microsoft
                                                            M. Scurtescu
                                                               M. Ansari
                                                              A. Nadalin
                                                            July 8, 2019

       Poll-Based Security Event Token (SET) Delivery Using HTTP


   This specification defines how a series of Security Event Tokens
   (SETs) may be delivered to an intended recipient using HTTP POST over
   TLS initiated as a poll by the recipient.  The specification also
   defines how delivery can be assured, subject to the SET Recipient's
   need for assurance.

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

   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 January 9, 2020.

Copyright Notice

   Copyright (c) 2019 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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   ( 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.  Polling Delivery using HTTP . . . . . . . . . . . . . . .   4
     2.2.  Polling HTTP Request  . . . . . . . . . . . . . . . . . .   4
     2.3.  Polling HTTP Response . . . . . . . . . . . . . . . . . .   5
     2.4.  Poll Request  . . . . . . . . . . . . . . . . . . . . . .   6
       2.4.1.  Poll Only Request . . . . . . . . . . . . . . . . . .   7
       2.4.2.  Acknowledge Only Request  . . . . . . . . . . . . . .   7
       2.4.3.  Poll with Acknowledgement . . . . . . . . . . . . . .   8
       2.4.4.  Poll with Acknowledgement and Errors  . . . . . . . .   9
     2.5.  Poll Response . . . . . . . . . . . . . . . . . . . . . .  10
     2.6.  Error Response Handling . . . . . . . . . . . . . . . . .  12
   3.  Authentication and Authorization  . . . . . . . . . . . . . .  12
     3.1.  Use of Tokens as Authorizations . . . . . . . . . . . . .  13
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  14
     4.1.  Authentication Using Signed SETs  . . . . . . . . . . . .  14
     4.2.  HTTP Considerations . . . . . . . . . . . . . . . . . . .  14
     4.3.  Confidentiality of SETs . . . . . . . . . . . . . . . . .  14
     4.4.  Access Token Considerations . . . . . . . . . . . . . . .  15
       4.4.1.  Bearer Token Considerations . . . . . . . . . . . . .  15
   5.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  15
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  16
   7.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  16
     7.1.  Normative References  . . . . . . . . . . . . . . . . . .  16
     7.2.  Informative References  . . . . . . . . . . . . . . . . .  17
   Appendix A.  Acknowledgments  . . . . . . . . . . . . . . . . . .  18
   Appendix B.  Change Log . . . . . . . . . . . . . . . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  19

1.  Introduction and Overview

   This specification defines how a stream of Security Event Tokens
   (SETs) [RFC8417] can be transmitted to an intended SET Recipient
   using HTTP [RFC7231] over TLS.  The specification defines a method to
   poll for SETs using HTTP POST.

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   A mechanism for exchanging configuration metadata such as endpoint
   URLs and cryptographic key parameters between the transmitter and
   recipient is out of scope for this specification.

1.1.  Notational Conventions

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "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 document, 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

2.  SET Delivery

   When an event occurs, the SET Transmitter constructs a SET [RFC8417]
   that describes the event.  The SET Transmitter determines the SET
   Recipients that the SET should be distributed to.

   How SETs are defined and the process by which events are identified
   for SET Recipients is out of scope of this specification.

   When a SET is available for a SET Recipient, the SET Transmitter
   attempts to deliver the SET by queueing the SET in a buffer so that a
   SET Recipient can poll for SETs using HTTP/1.1 POST.

   In Poll-Based SET Delivery Using HTTP, zero or more SETs are
   delivered in a JSON [RFC8259] document to a SET Recipient in response
   to an HTTP POST request to the SET Transmitter.  Then in a following
   request, the SET Recipient acknowledges received SETs and can poll
   for more.  All requests and responses are JSON documents and use a
   "Content-Type" of "application/json", as described in Section 2.1.

   After successful (acknowledged) SET delivery, SET Transmitters are
   not be required to retain or record SETs for retransmission.  Once a
   SET is acknowledged, the SET Recipient SHALL be responsible for
   retention, if needed.

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   Transmitted SETs SHOULD be self-validating (signed) if there is a
   requirement to verify they were issued by the SET Transmitter at a
   later date when de-coupled from the original delivery where
   authenticity could be checked via the HTTP or TLS mutual

   Upon receiving a SET, the SET Recipient reads the SET and validates
   it in the manner described in Section 2 of
   [I-D.ietf-secevent-http-push].  The SET Recipient MUST acknowledge
   receipt to the SET Transmitter.  The SET Recipient SHALL NOT use the
   event acknowledgement mechanism to report event errors other than
   relating to the parsing and validation of the SET.

2.1.  Polling Delivery using HTTP

   This method allows a SET Recipient to use HTTP POST (Section 4.3.3 of
   [RFC7231]) to acknowledge SETs and to check for and receive zero or
   more SETs.  Requests MAY be made at a periodic interval (short
   polling) or requests MAY wait, pending availability of new SETs using
   long polling, per Section 2 of [RFC6202].

   The delivery of SETs in this method is facilitated by HTTP POST
   requests initiated by the SET Recipient in which:

   o  The SET Recipient makes a request for available SETs using an HTTP
      POST to a pre-arranged endpoint provided by the SET Transmitter

   o  after validating previously received SETs, the SET Recipient
      initiates another poll request using HTTP POST that includes
      acknowledgement of previous SETs and waits for the next batch of

   The purpose of the acknowledgement is to inform the SET Transmitter
   that delivery has succeeded and redelivery is no longer required.
   Before acknowledgement, SET Recipients SHOULD ensure that received
   SETs have been validated and retained in a manner appropriate to the
   recipient's requirements.  The level and method of retention of SETs
   by SET Recipients is out of scope of this specification.

2.2.  Polling HTTP Request

   When initiating a poll request, the SET Recipient constructs a JSON
   document that consists of polling request parameters and SET
   acknowledgement parameters in the form of JSON objects.  The request
   payloads are delivered in a JSON document, as described in
   Section 2.4 and Section 2.5.

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   When making a request, the HTTP header "Content-Type" is set to

   The following JSON object members are used in a polling request:

   Request Processing Parameters

         An OPTIONAL JSON integer value indicating the maximum number of
         unacknowledged SETs that SHOULD be returned.  If more than the
         maximum number of SETs are available, the oldest SETs available
         SHOULD be returned first.  A value of "0" MAY be used by SET
         Recipients that would like to perform an acknowledge only
         request.  This enables the Recipient to use separate HTTP
         requests for acknowledgement and reception of SETs.  If this
         parameter is omitted, no limit is placed on the number of SETs
         to be returned.

         An OPTIONAL JSON boolean value that indicates the SET
         Transmitter SHOULD return an immediate response even if no
         results are available (short polling).  The default value is
         "false", which indicates the request is to be treated as an
         HTTP Long Poll, per Section 2 of [RFC6202].  The timeout for
         the request is part of the configuration between the
         participants, which is out of scope of this specification.

   SET Acknowledgment Parameters

         An array of strings that each corresponds to the "jti" of a
         successfully received SET.  If there are no outstanding SETs to
         acknowledge, the member MAY be omitted.  When acknowledging a
         SET, the SET Transmitter is released from any obligation to
         retain the SET.

         A JSON Object that contains one or more nested JSON object
         members that correspond to the "jti" of each invalid SET
         received.  The value of each is a JSON object whose contents is
         an "err" member and "description" member, whose values
         correspond to the errors described in Section 2.6.

2.3.  Polling HTTP Response

   In response to a poll request, the SET Transmitter checks for
   available SETs and responds with a JSON document containing the
   following JSON object members:

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      A JSON object that contains zero or more nested JSON objects.
      Each nested JSON object corresponds to the "jti" of a SET to be
      delivered and whose value is a JSON string containing the value of
      the encoded corresponding SET.  If there are no outstanding SETs
      to be transmitted, the JSON object SHALL be empty.

      A JSON boolean value that indicates if more unacknowledged SETs
      are available to be returned.

   When making a response, the HTTP header "Content-Type" is set to

2.4.  Poll Request

   The SET Recipient performs an HTTP POST (see Section 4.3.4 of
   [RFC7231]) to a pre-arranged polling endpoint URI to check for SETs
   that are available.  Because the SET Recipient has no prior SETs to
   acknowledge, the "ack" and "errs" request parameters are omitted.

   If after a period of time, negotiated between the SET Transmitter and
   Recipient, a SET Transmitter MAY redeliver SETs it has previously
   delivered.  The SET Recipient SHOULD accept repeat SETs and
   acknowledge the SETs regardless of whether the Recipient believes it
   has already acknowledged the SETs previously.  A SET Transmitter MAY
   limit the number of times it attempts to deliver a SET.

   If the SET Recipient has received SETs from the SET Transmitter, the
   SET Recipient SHOULD parse and validate received SETs to meet its own
   requirements and SHOULD acknowledge receipt in a timely fashion
   (e.g., seconds or minutes) so that the SET Transmitter can mark the
   SETs as received.  SET Recipients SHOULD acknowledge receipt before
   taking any local actions based on the SETs to avoid unnecessary delay
   in acknowledgement, where possible.

   Poll requests have three variations:

   Poll Only
      In which a SET Recipient asks for the next set of events where no
      previous SET deliveries are acknowledged (such as in the initial
      poll request).

   Acknowledge Only
      In which a SET Recipient sets the "maxEvents" value to "0" along
      with "ack" and "err" members indicating the SET Recipient is
      acknowledging previously received SETs and does not want to
      receive any new SETs in response to the request.

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   Combined Acknowledge and Poll
      In which a SET Recipient is both acknowledging previously received
      SETs using the "ack" and "err" members and will wait for the next
      group of SETs in the SET Transmitters response.

2.4.1.  Poll Only Request

   In the case where no SETs were received in a previous poll (see
   Figure 7), the SET Recipient simply polls without acknowledgement
   parameters ("sets" and "setErrs").

   The following is an example request made by a SET Recipient that has
   no outstanding SETs to acknowledge and is polling for available SETs
   at the endpoint "":

   POST /Events HTTP/1.1

   Authorization: Bearer h480djs93hd8
   Accept: application/json

    "returnImmediately": true

                  Figure 1: Example Initial Poll Request

   A SET Recipient can poll using default parameter values by passing an
   empty JSON object.

   The following is a non-normative example default poll request to the
   endpoint "":

   POST /Events HTTP/1.1

   Authorization: Bearer h480djs93hd8
   Accept: application/json


                  Figure 2: Example Default Poll Request

2.4.2.  Acknowledge Only Request

   In this variation, the SET Recipient acknowledges previously received
   SETs and indicates it does not want to receive SETs in response by
   setting the "maxEvents" value to "0".

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   This variation might be used, for instance, when a SET Recipient
   needs to acknowledge received SETs independently (e.g., on separate
   threads) from the process of receiving SETs.

   The following is a non-normative example poll request with
   acknowledgement of SETs received (for example as shown in Figure 6):

   POST /Events HTTP/1.1

   Authorization: Bearer h480djs93hd8
   Content-Type: application/json
   Authorization: Bearer h480djs93hd8

     "ack": [
     "maxEvents": 0,
     "returnImmediately": true

                Figure 3: Example Acknowledge Only Request

2.4.3.  Poll with Acknowledgement

   This variation allows a recipient thread to simultaneously
   acknowledge previously received SETs and wait for the next group of
   SETs in a single request.

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   The following is a non-normative example poll with acknowledgement of
   the SETs received in Figure 6:

   POST /Events HTTP/1.1

   Authorization: Bearer h480djs93hd8
   Content-Type: application/json
   Authorization: Bearer h480djs93hd8

     "ack": [
     "returnImmediately": false

         Figure 4: Example Poll with Acknowledgement and No Errors

   In the above acknowledgement, the SET Recipient has acknowledged
   receipt of two SETs and has indicated it wants to wait until the next
   SET is available.

2.4.4.  Poll with Acknowledgement and Errors

   In the case where errors were detected in previously delivered SETs,
   the SET Recipient MAY use the "setErrs" member to communicate the
   errors in the following poll request.

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   The following is a non-normative example of a response acknowledging
   one successfully received SET and one SET with an error from the two
   SETs received in Figure 6:

   POST /Events HTTP/1.1

   Authorization: Bearer h480djs93hd8
   Content-Type: application/json
   Authorization: Bearer h480djs93hd8

     "ack": ["3d0c3cf797584bd193bd0fb1bd4e7d30"],
     "setErrs": {
       "4d3559ec67504aaba65d40b0363faad8": {
         "err": "jwtAud",
         "description": "The audience value was invalid."
     "returnImmediately": true

             Figure 5: Example Poll Acknowledgement with Error

2.5.  Poll Response

   In response to a poll request, the service provider MAY respond
   immediately if SETs are available to be delivered.  If no SETs are
   available at the time of the request, the SET Transmitter SHALL delay
   responding until a SET is available or the timeout interval has
   elapsed unless the poll request parameter "returnImmediately" is

   As described in Section 2.3, a JSON document is returned containing a
   number of members including "sets", which SHALL contain zero or more

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   The following is a non-normative example response to the request
   shown in Section 2.4.  This example shows two SETs being returned:

  HTTP/1.1 200 OK
  Content-Type: application/json
  Location: https://notify.exampleidp/Events

  "sets": {

                      Figure 6: Example Poll Response

   In the above example, two SETs whose "jti" values are
   "4d3559ec67504aaba65d40b0363faad8" and
   "3d0c3cf797584bd193bd0fb1bd4e7d30" are delivered.

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   The following is a non-normative example response to the request
   shown in Section 2.4, which indicates that no new SETs or
   unacknowledged SETs are available:

   HTTP/1.1 200 OK
   Content-Type: application/json
   Location: https://notify.exampleidp/Events

    "sets": {}

                  Figure 7: Example No SETs Poll Response

   Upon receiving the JSON document (e.g., as shown in Figure 6), the
   SET Recipient parses and verifies the received SETs and notifies the
   SET Transmitter via the next poll request to the SET Transmitter, as
   described in Section 2.4.3 or Section 2.4.4.

2.6.  Error Response Handling

   If a SET is invalid, error codes from the IANA "Security Event Token
   Delivery Error Codes" registry established by
   [I-D.ietf-secevent-http-push] are used in error responses.  As
   described in Section 2.3 of [I-D.ietf-secevent-http-push], an error
   response is a JSON object providing details about the error that
   includes the following name/value pairs:

      A value from the IANA "Security Event Token Delivery Error Codes"
      registry that identifies the error.

      A human-readable string that provides additional diagnostic

   When included as part of a batch of SETs, the above JSON is included
   as part of the "setErrs" member, as defined in Section 2.3 and
   Section 2.4.4.

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].  For
   example, the following methodologies could be used among others:

   TLS Client Authentication

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      Event delivery endpoints MAY request TLS mutual client
      authentication, per Section 7.3 of [RFC5246].

   Bearer Tokens
      Bearer tokens [RFC6750] MAY be used when combined with TLS and a
      token framework such as OAuth 2.0 [RFC6749].  For security
      considerations regarding the use of bearer tokens in SET delivery,
      see Section 4.4.1.

   Basic Authentication
      Use of HTTP BASIC authentication should be avoided due to its use
      of a single factor that is based upon a relatively static,
      symmetric secret.  When used, implementers SHOULD combine the use
      of basic authentication with other factors.  The security
      considerations of HTTP BASIC are well documented in [RFC7617] and
      SHOULD be considered along with using signed SETs, as described in
      Section 4.1.

   As per Section 4.1 of [RFC7235], a SET delivery endpoint SHALL
   indicate supported HTTP authentication schemes via the "WWW-
   Authenticate" header.

   Authorization for the ability to pick-up or deliver SETs can be
   determined by using the identity of the SET issuer, or via an
   authentication method above.  This specification considers
   authentication as a feature to prevent denial-of-service attacks.
   Because SETs are not commands, SET Recipients are free to ignore SETs
   that are not of interest after acknowledging their receipt.

   For illustrative purposes only, SET delivery examples show an OAuth
   2.0 bearer token value [RFC6750] in the authorization header.  This
   is not intended to imply that bearer tokens are preferred.  However,
   the use of bearer tokens in the specification does reflect common

3.1.  Use of Tokens as Authorizations

   When using bearer tokens or proof-of-possession tokens that represent
   an authorization grant such as issued by OAuth (see [RFC6749]),
   implementers SHOULD consider the type of authorization granted, any
   authorized scopes (see Section 3.3 of [RFC6749]), and the security
   subject(s) that SHOULD be mapped from the authorization when
   considering local access control rules.  Section 6 of the OAuth
   Assertion Framework specification [RFC7521] documents common
   scenarios for authorization including:

   o  Clients using an assertion to authenticate and/or act on behalf of

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   o  Clients acting on behalf of a user; and,

   o  A Client acting on behalf of an anonymous user.

   When using OAuth access tokens, implementers MUST take into account
   the threats and countermeasures documented in the security
   considerations for the use of client authorizations (see Section 8 of
   [RFC7521]).  When using other token formats or frameworks,
   implementers MUST take into account similar threats and
   countermeasures, especially those documented by the relevant

4.  Security Considerations

4.1.  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 Section 5 of [RFC8417]).  This enables the SET
   Recipient to validate that the SET issuer is authorized to deliver
   the SET.

4.2.  HTTP Considerations

   SET delivery depends on the use of Hypertext Transfer Protocol and is
   thus subject to the security considerations of HTTP Section 9 of
   [RFC7230] and its related specifications.

   As stated in Section 2.7.1 of [RFC7230], an HTTP requestor MUST NOT
   generate the "userinfo" (i.e., username and password) component (and
   its "@" delimiter) when an "http" URI reference is generated with a
   message, as they are now disallowed in HTTP.

4.3.  Confidentiality of SETs

   SETs may contain sensitive information that is considered Personally
   Identifiable Information (PII).  In such cases, SET Transmitters and
   SET Recipients MUST protect the confidentiality of the SET contents
   by encrypting the SET as described in JWE [RFC7516], using a
   transport-layer security mechanism such as TLS, or both.  If an Event
   delivery endpoint supports TLS, it MUST support at least TLS version
   1.2 [RFC5246] and SHOULD support the newest version of TLS that meets
   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].

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4.4.  Access Token Considerations

   When using access tokens, such as those issued by OAuth 2.0
   [RFC6749], implementers MUST take into account threats and
   countermeasures documented in Section 8 of [RFC7521].

4.4.1.  Bearer Token Considerations

   Due to the possibility of interception, Bearer tokens MUST be
   exchanged using TLS.

   Bearer tokens MUST have a limited lifetime that can be determined
   directly or indirectly (e.g., by checking with a validation service)
   by the service provider.  By expiring tokens, clients are forced to
   obtain a new token (which usually involves re-authentication) for
   continued authorized access.  For example, in OAuth 2.0, a client MAY
   use an OAuth refresh token to obtain a new bearer token after
   authenticating to an authorization server, per Section 6 of

   Implementations supporting OAuth bearer tokens need to factor in
   security considerations of this authorization method [RFC7521].
   Since security is only as good as the weakest link, implementers also
   need to consider authentication choices coupled with OAuth bearer
   tokens.  The security considerations of the default authentication
   method for OAuth bearer tokens, HTTP BASIC, are well documented in
   [RFC7617], therefore implementers are encouraged to prefer stronger
   authentication methods.  Designating the specific methods of
   authentication and authorization are out of scope for the delivery of
   SETs, however this information is provided as a resource to

5.  Privacy Considerations

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

   SET Transmitters SHOULD attempt to deliver SETs that are 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, 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

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   example, the passing of a hash value that requires the subscriber to
   already know the subject.

6.  IANA Considerations

   This specification requires no IANA actions.

7.  References

7.1.  Normative References

              Backman, A., Jones, M., Scurtescu, M., Ansari, M., and A.
              Nadalin, "Push-Based Security Event Token (SET) Delivery
              Using HTTP", draft-ietf-secevent-http-push-06 (work in
              progress), May 2019.

   [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, <>.

   [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,

   [RFC7515]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web
              Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
              2015, <>.

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   [RFC7516]  Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
              RFC 7516, DOI 10.17487/RFC7516, May 2015,

   [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, <>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,

   [RFC8417]  Hunt, P., Ed., Jones, M., Denniss, W., and M. Ansari,
              "Security Event Token (SET)", RFC 8417,
              DOI 10.17487/RFC8417, July 2018,

7.2.  Informative References

   [RFC3339]  Klyne, G. and C. Newman, "Date and Time on the Internet:
              Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,

   [RFC6202]  Loreto, S., Saint-Andre, P., Salsano, S., and G. Wilkins,
              "Known Issues and Best Practices for the Use of Long
              Polling and Streaming in Bidirectional HTTP", RFC 6202,
              DOI 10.17487/RFC6202, April 2011,

   [RFC6749]  Hardt, D., Ed., "The OAuth 2.0 Authorization Framework",
              RFC 6749, DOI 10.17487/RFC6749, October 2012,

   [RFC6750]  Jones, M. and D. Hardt, "The OAuth 2.0 Authorization
              Framework: Bearer Token Usage", RFC 6750,
              DOI 10.17487/RFC6750, October 2012,

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   [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,

   [RFC7235]  Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
              Protocol (HTTP/1.1): Authentication", RFC 7235,
              DOI 10.17487/RFC7235, June 2014,

   [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, <>.

   [RFC7617]  Reschke, J., "The 'Basic' HTTP Authentication Scheme",
              RFC 7617, DOI 10.17487/RFC7617, September 2015,

Appendix A.  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 the authors
   of draft-ietf-secevent-delivery-02, on which this specification is

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

Appendix B.  Change Log

   [[ to be removed by the RFC Editor before publication as an RFC ]]

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

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

   o  Removed references to the HTTP Push delivery method.

   Draft 01 - mbj:

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

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   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.

   o  Begun eliminating redundancies between this specification and
      "Push-Based Security Event Token (SET) Delivery Using HTTP"
      [I-D.ietf-secevent-http-push], referencing, rather that
      duplicating common normative text.

   Draft 02 - mbj:

   o  Removed vestigial language remaining from when the push and poll
      delivery methods were defined in a common specification.

   o  Replaced remaining uses of the terms Event Transmitter and Event
      Recipient with the correct terms SET Transmitter and SET

   o  Removed uses of the unnecessary term "Event Stream".

   o  Removed dependencies between the semantics of "maxEvents" and

   o  Said that PII in SETs is to be encrypted with TLS, JWE, or both.

   o  Corrected grammar and spelling errors.

   Draft 03 - mbj:

   o  Corrected uses of "attribute" to "member" when describing JSON

   o  Further alignment with the push draft.

Authors' Addresses

   Annabelle Backman (editor)


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   Michael B. Jones (editor)


   Marius Scurtescu


   Morteza Ansari


   Anthony Nadalin


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