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Versions: (draft-ietf-sipcore-sip-authn) 00 01 02 03 04 05 06 07 08 09 10 11 12

SIP Core                                                  R. Shekh-Yusef
Internet-Draft                                                     Avaya
Updates: 3261 (if approved)                                  C. Holmberg
Intended status: Standards Track                                Ericsson
Expires: 25 September 2020                                    V. Pascual
                                                             webrtchacks
                                                           24 March 2020


  Third-Party Token-based Authentication and Authorization for Session
                       Initiation Protocol (SIP)
                 draft-ietf-sipcore-sip-token-authnz-12

Abstract

   This document defines the "Bearer" authentication scheme for the
   Session Initiation Protocol (SIP), and a mechanism by which user
   authentication and SIP registration authorization is delegated to a
   third party, using the OAuth 2.0 framework and OpenID Connect Core
   1.0.  This document updates RFC 3261 to provide guidance on how a SIP
   User Agent Client (UAC) responds to a SIP 401/407 response that
   contains multiple WWW-Authenticate/Proxy-Authenticate header fields.

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 25 September 2020.

Copyright Notice

   Copyright (c) 2020 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 (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  SIP User Agent Types  . . . . . . . . . . . . . . . . . .   3
     1.3.  Token Types and Formats . . . . . . . . . . . . . . . . .   3
     1.4.  Example Flows . . . . . . . . . . . . . . . . . . . . . .   4
       1.4.1.  Registration  . . . . . . . . . . . . . . . . . . . .   4
       1.4.2.  Registration with Preconfigured AS  . . . . . . . . .   6
   2.  SIP Procedures  . . . . . . . . . . . . . . . . . . . . . . .   7
     2.1.  UAC Behavior  . . . . . . . . . . . . . . . . . . . . . .   7
       2.1.1.  Obtaining Tokens and Responding to Challenges . . . .   7
       2.1.2.  Protecting the Access Token . . . . . . . . . . . . .   8
       2.1.3.  REGISTER Request  . . . . . . . . . . . . . . . . . .   8
       2.1.4.  Non-REGISTER Request  . . . . . . . . . . . . . . . .   9
     2.2.  UAS and Registrar Behavior  . . . . . . . . . . . . . . .   9
     2.3.  Proxy Behavior  . . . . . . . . . . . . . . . . . . . . .  10
   3.  Access Token Claims . . . . . . . . . . . . . . . . . . . . .  10
   4.  WWW-Authenticate Response Header Field  . . . . . . . . . . .  10
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   7.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  12
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   The Session Initiation Protocol (SIP) [RFC3261] uses the same
   framework as HTTP [RFC7230] to authenticate users: a simple
   challenge-response authentication mechanism that allows a SIP server
   to challenge a SIP client request and allows a SIP client to provide
   authentication information in response to that challenge.

   OAuth 2.0 [RFC6749] defines a token-based authorization framework to
   allow an OAuth client to access resources on behalf of its user.

   The OpenID Connect 1.0 specification [OPENID] defines a simple
   identity layer on top of the OAuth 2.0 protocol, which enables
   clients to verify the identity of the user based on the
   authentication performed by a dedicated authorization server, as well
   as to obtain basic profile information about the user.




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   This document defines the "Bearer" authentication scheme for the
   Session Initiation Protocol (SIP), and a mechanism by which user
   authentication and SIP registration authorization is delegated to a
   third party, using the OAuth 2.0 framework and OpenID Connect Core
   1.0.  This kind of user authentication enables the single-sign-on
   feature, which allows the user to authenticate once and gain access
   to both SIP and non-SIP services.

   This document also updates [RFC3261], by defining the User Agent
   Client (UAC) procedures when a UAC receives a 401/407 response with
   multiple WWW-Authenticate/Proxy-Authenticate header fields, providing
   challenges using different authentication schemes for the same realm.


1.1.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in BCP 14 [RFC2119]
   [RFC8174] when, and only when, they appear in all capitals, as shown
   here.


1.2.  SIP User Agent Types

   The OAuth 2.0 authorization framework [RFC6749] defines two types of
   clients, confidential and public, that apply to the SIP UACs.

   *  Confidential User Agent: a SIP UAC that is capable of maintaining
      the confidentiality of the user credentials and any tokens
      obtained using these user credentials.

   *  Public User Agent: a SIP UAC that is incapable of maintaining the
      confidentiality of the user credentials and any obtained tokens.

   The mechanism defined in this document MUST only be used with
   Confidential User Agents, as the UAC is expected to obtain and
   maintain tokens to be able to access the SIP network.


1.3.  Token Types and Formats

   The tokens used in third-party authorization depend on the type of
   authorization server (AS).

   An OAuth authorization server provides the following tokens to a
   successfully authorized UAC:




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   *  Access token: the UAC will use this token to gain access to
      services by providing the token to a SIP server.

   *  Refresh token: the UAC will present this token to the AS to
      refresh a stale access token.

   An OpenID Connect server returns an additional token:

   *  ID Token: this token contains the SIP URI and other user-specific
      details that will be consumed by the UAC.

   Tokens can be represented in two different formats:

   *  Structured Token: a token that consists of a structured object
      that contains the claims associated with the token, e.g.  JWT as
      defined in [RFC7519].

   *  Reference Token: a token that consists of a random string that is
      used to obtain the details of the token and its associated claims,
      as defined in [RFC6749].

   Access Tokens could be represented in one of the above two formats.
   Refresh Tokens usualy are represented in a reference format, as this
   token is consumed only the AS that issued the token.  ID Token is
   defined as a structured token in the form of a JWT.


1.4.  Example Flows

1.4.1.  Registration

   Figure 1 below shows an example of a SIP registration, where the
   registrar informs the UAC about the authorization server from which
   the UAC can obtain an access token in a 401 response to the REGISTER
   request.
















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     UAC                         Registrar                          AS
   ---------------------------------------------------------------------
     |                               |                               |
     | [1] REGISTER                  |                               |
     |------------------------------>|                               |
     |                               |                               |
     | [2] 401 Unauthorized          |                               |
     |     WWW-Authenticate: Bearer "authz_server"="<authz_server>"  |
     |<------------------------------|                               |
     |                               |                               |
     | [3] The UAC interacts with the AS and obtains tokens, using   |
     |     some out-of-scope mechanism.                              |
     |<=============================================================>|
     |                               |                               |
     | [4] REGISTER                  |                               |
     |     Authorization: Bearer <access_token>                      |
     |------------------------------>|                               |
     |                               | [5] HTTP POST /introspect     |
     |                               |     {access_token}            |
     |                               |------------------------------>|
     |                               |                               |
     |                               | [6] 200 OK {metadata}         |
     |                               |<------------------------------|
     |                               |                               |
     | [7] 200 OK                    |                               |
     |<------------------------------|                               |
     |                               |                               |

                    Figure 1: Example Registration Flow

   In step [1], the UAC starts the registration process by sending a SIP
   REGISTER request to the registrar without any credentials.

   In step [2], the registrar challenges the UA, by sending a SIP 401
   (Unauthorized) response to the REGISTER request.  In the response,
   the registrar includes information about the AS to contact in order
   to obtain a token.

   In step [3], the UAC interacts with the AS via an out-of-scope
   mechanism, potentially using the OAuth Native App mechanism defined
   in [RFC8252].  The AS authenticates the user and provides the UAC
   with the tokens needed to access the SIP service.

   In step [4], the UAC retries the registration process by sending a
   new REGISTER request that includes the access token that the UAC
   obtained previously.





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   The registrar validates the access token.  If the access token is a
   reference token, the registrar MAY perform an introspection
   [RFC7662], as in steps [5] and [6], in order to obtain more
   information about the access token and its scope, per [RFC7662].
   Otherwise, after the registrar validates the token to make sure it
   was signed by a trusted entity, it inspects its claims and acts upon
   it.

   In step [7], once the registrar has successfully verified and
   accepted the access token, it sends a 200 (OK) response to the
   REGISTER request.


1.4.2.  Registration with Preconfigured AS

   Figure 2 shows an example of a SIP registration where the UAC has
   been preconfigured with information about the AS from which to obtain
   the access token.

     UAC                         Registrar                          AS
   ---------------------------------------------------------------------
     |                               |                               |
     | [1] The UAC interacts with the AS and obtains tokens, using   |
     |     some out of scope mechanism.                              |
     |<=============================================================>|
     |                               |                               |
     | [2] REGISTER                  |                               |
     |     Authorization: Bearer <access_token>                      |
     |------------------------------>|                               |
     |                               | [3] HTTP POST /introspect     |
     |                               |     {access_token}            |
     |                               |------------------------------>|
     |                               |                               |
     |                               | [4] 200 OK {metadata}         |
     |                               |<------------------------------|
     |                               |                               |
     | [5] 200 OK                    |                               |
     |<------------------------------|                               |
     |                               |                               |

         Figure 2: Example Registration Flow - Authorization Server
                         Information Preconfigured

   In step [1], the UAC interacts with the AS using an out-of-scope
   mechanism, potentially using the OAuth Native App mechanism defined
   in [RFC8252].  The AS authenticates the user and provides the UAC
   with the tokens needed to access the SIP service.




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   In step [2], the UAC initiates the registration process by sending a
   new REGISTER request that includes the access token that the UAC
   obtained previously.

   The registrar validates the access token.  If the access token is a
   reference token, the registrar MAY perform an introspection, as in
   steps [3] and [4], in order to obtain more information about the
   access token and its scope, per [RFC7662].  Otherwise, after the
   registrar validates the token to make sure it was signed by a trusted
   entity, it inspects its claims and acts upon it.

   In step [5], once the registrar has successfully verified and
   accepted the access token, it sends a 200 (OK) response to the
   REGISTER request.


2.  SIP Procedures

   Section 22 of [RFC3261] defines the SIP procedures for the Digest
   authentication mechanism.  The same procedures apply to the Bearer
   authentication mechanism, with the changes described in this section.

2.1.  UAC Behavior

2.1.1.  Obtaining Tokens and Responding to Challenges

   When a UAC sends a request without credentials (or with invalid
   credentials), it could receive either a 401 (Unauthorized) response
   with a WWW-Authenticate header field or a 407 (Proxy Authentication
   Required) response with a Proxy-Authenticate header field.  If the
   WWW-Authenticate or Proxy-Authenticate header field indicates
   "Bearer" scheme authentication and contains an address to an
   authorization server, the UAC contacts the authorization server in
   order to obtain tokens, and includes the requested scopes, based on a
   local configuration (Figure 1).

   The detailed OAuth2 procedure to authenticate the user and obtain
   these tokens is out of scope of this document.  The address of the
   authorization server might already be known to the UAC via
   configuration.  In which case, the UAC can contact the authorization
   server for tokens before it sends a SIP request (Figure 2).
   Procedures for native applications are defined in [RFC8252].  When
   using the mechanism defined in [RFC8252] the user of the UAC will be
   directed to interact with the authorization server using a web
   browser, allowing the authorization server to prompt the user for
   multi-factor authentication, to redirect the user to third-party
   identity providers, and to enable the use of single-sign-on sessions.




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   The tokens returned to the UAC depend on the type of authorization
   server (AS): an OAuth AS provides an access token and refresh token
   [RFC6749].  The UAC provides the access token to the SIP servers to
   authorize UAC's access to the service.  The UAC uses the refresh
   token only with the AS to get a new access token and refresh token
   before the expiry of the current access token (see [RFC6749], section
   1.5 Refresh Token for details).  An OpenID Connect server returns an
   additional ID-Token containing the SIP URI and other user-specific
   details that will be consumed by the UAC.

   If the UAC receives a 401/407 response with multiple WWW-
   Authenticate/Proxy-Authenticate header fields, providing challenges
   using different authentication schemes for the same realm, the UAC
   provides credentials for one or more of the schemes that it supports,
   based on local policy.

   NOTE: The address of the Authorization Server might be known to the
   UAC e.g., using means of configuration, in which case the UAC can
   contact the Authorization Server in order to obtain the access token
   before it sends SIP request without credentials.

2.1.2.  Protecting the Access Token

   [RFC6749] mandates that access tokens are protected with TLS when in
   transit.  However, TLS only guarantees hop-to-hop protection when
   used to protect SIP signaling.  Therefore the access token MUST be
   protected in a way so that only authorized SIP servers will have
   access to it.  Endpoints that support this specification MUST support
   encrypted JSON Web Tokens (JWT) [RFC7519] for encoding and protecting
   access tokens when they are included in SIP requests, unless some
   other mechanism is used to guarantee that only authorized SIP
   endpoints have access to the access token.


2.1.3.  REGISTER Request

   The procedures in this section apply when the UAC has received a
   challenge that contains a "Bearer" scheme, and the UAC has obtained a
   token as specified in Section 2.1.1.

   The UAC sends a REGISTER request with an Authorization header field
   containing the response to the challenge, including the Bearer scheme
   carrying a valid access token in the request, as specified in
   [RFC6750].

   Note that, if there were multiple challenges with different schemes,
   then the UAC may be able to successfully retry the request using non-
   Bearer credentials.



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   Based on local policy, the UAC MAY include an access token that has
   been used for another binding associated with the same AOR in the
   request.

   If the access token included in a REGISTER request is not accepted,
   and the UAC receives a 401 response or a 407 response, the UAC
   follows the procedures in Section 2.1.1.


2.1.4.  Non-REGISTER Request

   The procedures in this section apply when the UAC has received a
   challenge that contains a "Bearer" scheme, and the UAC has obtained a
   token as specified in Section 2.1.1.

   When the UAC sends a request, it MUST include an Authorization header
   field with a Bearer scheme, carrying a valid access token in the
   request, as specified in [RFC6750].  Based on local policy, the UAC
   MAY include an access token that has been used for another dialog, or
   for another stand-alone request, if the target of the new request is
   the same.

   If the access token included in a request is not accepted, and the
   UAC receives a 401 response or a 407 response, the UAC follows the
   procedures in Section 2.1.1.


2.2.  UAS and Registrar Behavior

   When a UAS or Registrar receives a request that fails to contain
   authorization credentials acceptable to it, it SHOULD challenge the
   request by sending a 401 (Unauthorized) response.  To indicate that
   it is willing to accept an access token as a credential, the UAS/
   Registrar MUST include a Proxy-Authentication header field in the
   response that indicates "Bearer" scheme and includes an address of an
   authorization server from which the originator can obtain an access
   token.

   When a UAS/Registrar receives a SIP request that contains an
   Authorization header field with an access token, the UAS/Registrar
   MUST validate the access token, using the procedures associated with
   the type of access token (Structured or Reference) used, e.g.
   [RFC7519].  If the token provided is an expired access token, then
   the UAS MUST reply with 401 Unauthorized, as defined in section 3 of
   [RFC6750].  If the validation is successful, the UAS/Registrar can
   continue to process the request using normal SIP procedures.  If the
   validation fails, the UAS/Registrar MUST reject the request.




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2.3.  Proxy Behavior

   When a proxy receives a request that fails to contain authorization
   credentials acceptable to it, it SHOULD challenge the request by
   sending a 407 (Proxy Authentication Required) response.  To indicate
   that it is willing to accept an access token as a credential, the
   proxy MUST include a Proxy-Authentication header field in the
   response that indicates "Bearer" scheme and includes an address to an
   authorization server from which the originator can obtain an access
   token.

   When a proxy wishes to authenticate a received request, it MUST
   search the request for Proxy-Authorization header fields with 'realm'
   parameters that match its realm.  It then MUST successfully validate
   the credentials from at least one Proxy-Authorization header field
   for its realm.  When the scheme is "Bearer", the proxy MUST validate
   the access token, using the procedures associated with the type of
   access token (Structured or Reference) used, e.g., [RFC7519].


3.  Access Token Claims

   The type of services to which an access token grants access can be
   determined using different methods.  The methods used and the access
   provided by the token is based on local policy agreed between the AS
   and the registrar.

   If an access token is encoded as a JWT, it might contain a list of
   claims [RFC7519], some registered and some application-specific.  The
   REGISTRAR can grant access to services based on such claims, some
   other mechanism, or a combination of claims and some other mechanism.
   If an access token is a reference token, the REGISTRAR will grant
   access based on some other mechanism.  Examples of such other
   mechanisms are introspection [RFC7662], user profile lookups, etc.


4.  WWW-Authenticate Response Header Field

   This section uses ABNF [RFC5234] to describe the syntax of the WWW-
   Authenticate header field when used with the "Bearer" scheme to
   challenge the UAC for credentials, by extending the 'challenge'
   parameter defined by [RFC3261].









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       challenge  =/  ("Bearer" LWS bearer-cln *(COMMA bearer-cln))
       bearer-cln = realm / scope / authz-server / error /
                    auth-param
       authz-server = "authz_server" EQUAL authz-server-value
       authz-server-value = https-URI
       realm = <defined in RFC3261>
       auth-param = <defined in RFC3261>
       scope = <defined in RFC6749>
       error = <defined in RFC6749>
       https-URI = <defined in RFC7230>

                       Figure 3: Bearer Scheme Syntax

   The authz-server parameter contains the HTTPS URI, as defined in
   [RFC7230], of the authorization server.  The UAC can discover
   metadata about the AS using a mechanism like the one defined in
   [RFC8414].

   The realm and auth-param parameters are defined in [RFC3261].

   Per [RFC3261], the realm string alone defines the protection domain.
   [RFC3261] states that the realm string must be globally unique and
   recommends that the realm string contain a hostname or domain name.
   It also states that the realm string should be a human-readable
   identifier that can be rendered to the user.

   The scope and error parameters are defined in [RFC6749].

   The scope parameter could be used by the registrar/proxy to indicate
   to the UAC the minimum scope that must be associated with the access
   token to be able to get service.  As defined in [RFC6749], the value
   of the scope parameter is expressed as a list of space-delimited,
   case-sensitive strings.  The strings are defined by the authorization
   server.  The values of the scope parameter are out of scope of this
   document.  The UAC will use the scope provided by the registrar to
   contact the AS and obtain a proper token with the requested scope.

   The error parameter could be used by the registrar/proxy to indicate
   to the UAC the reason for the error, with possible values of
   "invalid_token" or "invalid_scope".











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5.  Security Considerations

   The security considerations for OAuth are defined in [RFC6749].  The
   security considerations for bearer tokens are defined in [RFC6750].
   The security considerations for JSON Web Tokens (JWT) are defined in
   [RFC7519].  These security considerations also apply to SIP usage of
   access token as defined in this document.

   [RFC6749] mandates that access tokens are protected with TLS.
   However, TLS only guarantees hop-to-hop protection when used to
   protect SIP signaling.  Therefore the access token MUST be protected
   in a way so that only authorized SIP endpoints will have access to
   it.  Endpoints that support this specification MUST support encrypted
   JSON Web Tokens (JWT) [RFC7519] for encoding and protecting access
   tokens when included in SIP requests, unless some other mechanism is
   used to guarantee that only authorized SIP endpoints have access to
   the access token.


6.  IANA Considerations

7.  Acknowledgments

   The authors would like to specially thank Paul Kyzivat for his
   multiple detailed reviews and suggested text that significantly
   improved the quality of the document.

   The authors would also like to thank the following for their review
   and feedback on this document:

   Olle Johansson, Roman Shpount, Dale Worley, and Jorgen Axell.

   The authors would also like to thank the following for their review
   and feedback of the original document that was replaced with this
   document:

   Andrew Allen, Martin Dolly, Keith Drage, Paul Kyzivat, Jon Peterson,
   Michael Procter, Roy Radhika, Matt Ryan, Ivo Sedlacek, Roman Shpount,
   Robert Sparks, Asveren Tolga, Dale Worley, and Yehoshua Gev.

   The authors would also like to specially thank Jean Mahoney for her
   multiple reviews, editorial help, and the coversion of the XML source
   file from v2 to v3.








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8.  Normative References

   [OPENID]   Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
              C. Mortimore, "OpenID Connect Core 1.0", February 2014.

   [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>.

   [RFC3261]  Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston,
              A., Peterson, J., Sparks, R., Handley, M., and E.
              Schooler, "SIP: Session Initiation Protocol", RFC 3261,
              DOI 10.17487/RFC3261, June 2002,
              <https://www.rfc-editor.org/info/rfc3261>.

   [RFC5234]  Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
              Specifications: ABNF", STD 68, RFC 5234,
              DOI 10.17487/RFC5234, January 2008,
              <https://www.rfc-editor.org/info/rfc5234>.

   [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>.

   [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>.

   [RFC7662]  Richer, J., Ed., "OAuth 2.0 Token Introspection",
              RFC 7662, DOI 10.17487/RFC7662, October 2015,
              <https://www.rfc-editor.org/info/rfc7662>.

   [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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Internet-Draft    3rd-Party Token-based AuthNZ for SIP        March 2020


   [RFC8252]  Denniss, W. and J. Bradley, "OAuth 2.0 for Native Apps",
              BCP 212, RFC 8252, DOI 10.17487/RFC8252, October 2017,
              <https://www.rfc-editor.org/info/rfc8252>.

   [RFC8414]  Jones, M., Sakimura, N., and J. Bradley, "OAuth 2.0
              Authorization Server Metadata", RFC 8414,
              DOI 10.17487/RFC8414, June 2018,
              <https://www.rfc-editor.org/info/rfc8414>.

Authors' Addresses

   Rifaat Shekh-Yusef
   Avaya
   425 Legget Drive
   Ottawa Ontario
   Canada

   Phone: +1-613-595-9106
   Email: rifaat.ietf@gmail.com


   Christer Holmberg
   Ericsson
   Hirsalantie 11
   FI- Jorvas  02420
   Finland

   Email: christer.holmberg@ericsson.com


   Victor Pascual
   webrtchacks
   Spain

   Email: victor.pascual.avila@gmail.com
















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