Internet DRAFT - draft-wendt-stir-passport-shaken

draft-wendt-stir-passport-shaken







stir                                                            C. Wendt
Internet-Draft                                                   Comcast
Intended status: Standards Track                               M. Barnes
Expires: May 3, 2018                         MLB@Realtime Communications
                                                        October 30, 2017


                   PASSporT SHAKEN Extension (SHAKEN)
                  draft-wendt-stir-passport-shaken-01

Abstract

   This document extends PASSporT, a token object that conveys
   cryptographically-signed information about the participants involved
   in personal communications, to include information defined as part of
   the SHAKEN [ATIS-1000074] specification for indicating an attestation
   level and originating ID.

Status of This Memo

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Copyright Notice

   Copyright (c) 2017 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

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   include Simplified BSD License text as described in Section 4.e of




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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Overview of 'shaken' PASSporT extension . . . . . . . . . . .   3
   4.  PASSporT 'attest' Claim . . . . . . . . . . . . . . . . . . .   3
   5.  PASSporT 'origid' Claim . . . . . . . . . . . . . . . . . . .   4
   6.  Example . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
   7.  Using 'shaken' in SIP . . . . . . . . . . . . . . . . . . . .   5
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
     8.1.  JSON Web Token claims . . . . . . . . . . . . . . . . . .   5
     8.2.  PASSporT Types  . . . . . . . . . . . . . . . . . . . . .   6
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   6
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     11.1.  Normative References . . . . . . . . . . . . . . . . . .   6
     11.2.  Informative References . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The SHAKEN specification defines a framework for using STIR protocols
   including PASSporT [I-D.ietf-stir-passport], RFC4474bis
   [I-D.ietf-stir-rfc4474bis] and the STIR certificate framework
   [I-D.ietf-stir-certificates] for implementing the cryptographic
   validation of an authorized originator of telephone calls using SIP.
   Because the current telephone network contains both VoIP and TDM/SS7
   originated traffic, there is many scenarios that need to be accounted
   for where PASSporT signatures may represent either direct or indirect
   call origination scenarios.  The SHAKEN [ATIS-1000074] specification
   defines levels of attribution of the origination of the call as well
   as an origination identifier that can help create a unique
   association with the origination of calls from various parts of the
   VoIP or TDM telephone network.  This document specifies these
   indicators as a specified PASSporT extension.

2.  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 [RFC2119].







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3.  Overview of 'shaken' PASSporT extension

   The SHAKEN framework is designed to use PASSporT
   [I-D.ietf-stir-passport] as a method of asserting the telephone
   number calling identity.  In addition to the PASSporT base claims,
   there are two additional claims that have been defined for the needs
   of a service provider to signal information beyond just the telephone
   identity.  First, in order to help bridge the transition of the state
   of the current telephone network which has calls with no
   authentication and non-SIP [RFC3261] signaling not compatible with
   the use of PASSporT and Secure Telephone Identity (STI) in general,
   there is an attestation claim.  This provides three levels of
   attestation, including a full attestation when the service provider
   can fully attest to the calling identity, a partial attestation, when
   the service provider originated a telephone call but can not fully
   attest to the calling identity, and a gateway attestation which is
   the lowest level of attestation and represents the service provider
   receiving a call from a non PASSporT or STI supporting telephone
   gateway.

   The second claim is a unique origination identifier that should be
   used by the service provider to identify different sources of
   telephone calls to support a traceback mechanism that can be used for
   enforcement and identification of a source of illegitimate calls.

   The next two sections define these new claims.

4.  PASSporT 'attest' Claim

   This indicator allows for both identifying the service provider that
   is vouching for the call as well as a clearly indicating what
   information the service provider is attesting to.  The 'attest' claim
   can be one of the following three values, 'A', 'B', or 'C' as defined
   in [ATIS-1000074].

   'A' represents 'Full Attestation' where the signing provider MUST
   satisfy all of the following conditions:

   o  Is responsible for the origination of the call onto the IP based
      service provider voice network.

   o  Has a direct authenticated relationship with the customer and can
      identify the customer.

   o  Has established a verified association with the telephone number
      used for the call.





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   'B' represents 'Partial Attestation' where the signing provider MUST
   satisfy all of the following conditions:

   o  Is responsible for the origination of the call onto its IP-based
      voice network.

   o  Has a direct authenticated relationship with the customer and can
      identify the customer.

   o  Has NOT established a verified association with the telephone
      number being used for the call.

   'C' represents 'Gateway Attestation' where the signing provider MUST
   satisfy all of the following conditions:

   o  Is the entry point of the call into its VoIP network.

   o  Has no relationship with the initiator of the call (e.g.,
      international gateways)

5.  PASSporT 'origid' Claim

   The purpose of the unique origination identifier is to assign an
   opaque identifier corresponding to the service provider-initiated
   calls themselves, customers, classes of devices, or other groupings
   that a service provider might want to use for determining things like
   reputation or trace back identification of customers or gateways.
   The value of 'origid' claim is a UUID as defined in [RFC4122].
   SHAKEN isn't prescriptive in the exact usage of origid other than the
   UUID format as a globally unique identifier representing the
   originator of the call to whatever granularity the PASSporT signer
   determines is sufficient for the ability to trace the original
   origination point of the call.  There will likely be best practices
   documents that more precisely guide it's usage in real deployments.

6.  Example















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   Protected Header
   {
      "alg":"ES256",
      "typ":"passport",
      "ppt":"shaken",
      "x5u":"https://cert.example.org/passport.crt"
   }
   Payload
   {
      "attest":"A"
      "dest":{"uri":["sip:alice@example.com"]}
      "iat":"1443208345",
      "orig":{"tn":"12155551212"},
      "origid":"123e4567-e89b-12d3-a456-426655440000"
   }

7.  Using 'shaken' in SIP

   The use of the 'shaken' PASSporT type and the claims 'attest' and
   'origid' are formally defined in [ATIS-1000074] for usage in SIP
   [RFC3261] aligned with the use of the identity header defined in
   [I-D.ietf-stir-rfc4474bis].  The carriage of the 'attest' and
   'origid' values are in the full PASSporT token included in the
   identity header as specified in [ATIS-1000074].

8.  IANA Considerations

8.1.  JSON Web Token claims

   This specification requests that the IANA add two new claims to the
   JSON Web Token Claims registry as defined in [RFC7519].

   Claim Name: "attest"

   Claim Description: Attestation level as defined in SHAKEN framework

   Change Controller: IESG

   Specification Document(s): [RFCThis]

   Claim Name: "origid"

   Claim Description: Originating Identifier as defined in SHAKEN
   framework

   Change Controller: IESG

   Specification Document(s): [RFCThis]



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8.2.  PASSporT Types

   This specification requests that the IANA add a new entry to the
   PASSporT Types registry for the type "shaken" which is specified in
   [RFCThis].

9.  Security Considerations

   TBD

10.  Acknowledgements

   TBD

11.  References

11.1.  Normative References

   [ATIS-1000074]
              ATIS/SIP Forum NNI Task Group, "Signature-based Handling
              of Asserted information using toKENs (SHAKEN)", January
              2017.

   [I-D.ietf-stir-certificates]
              Peterson, J. and S. Turner, "Secure Telephone Identity
              Credentials: Certificates", draft-ietf-stir-
              certificates-14 (work in progress), May 2017.

   [I-D.ietf-stir-passport]
              Wendt, C. and J. Peterson, "Personal Assertion Token
              (PASSporT)", draft-ietf-stir-passport-11 (work in
              progress), February 2017.

   [I-D.ietf-stir-rfc4474bis]
              Peterson, J., Jennings, C., Rescorla, E., and C. Wendt,
              "Authenticated Identity Management in the Session
              Initiation Protocol (SIP)", draft-ietf-stir-rfc4474bis-16
              (work in progress), February 2017.

   [RFC4122]  Leach, P., Mealling, M., and R. Salz, "A Universally
              Unique IDentifier (UUID) URN Namespace", RFC 4122,
              DOI 10.17487/RFC4122, July 2005,
              <https://www.rfc-editor.org/info/rfc4122>.

   [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>.




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11.2.  Informative 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>.

   [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>.

Authors' Addresses

   Chris Wendt
   Comcast
   One Comcast Center
   Philadelphia, PA  19103
   USA

   Email: chris-ietf@chriswendt.net


   Mary Barnes
   MLB@Realtime Communications

   Email: mary.ietf.barnes@gmail.com























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