PASSporT Extension for Diverted Calls
draft-ietf-stir-passport-divert-00

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Last updated 2017-07-05 (latest revision 2017-07-03)
Replaces draft-peterson-passport-divert
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Network Working Group                                        J. Peterson
Internet-Draft                                                   Neustar
Intended status: Informational                              July 3, 2017
Expires: January 4, 2018

                 PASSporT Extension for Diverted Calls
                 draft-ietf-stir-passport-divert-00.txt

Abstract

   This document extends PASSporT, which conveys cryptographically-
   signed information about the people involved in personal
   communications, to include an indication that a call has been
   diverted from its original destination to a new one.  This
   information can greatly improve the decisions made by verification
   services in call forwarding scenarios.

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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on January 4, 2018.

Copyright Notice

   Copyright (c) 2017 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
   (http://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

Peterson                 Expires January 4, 2018                [Page 1]
Internet-Draft              STIR Caller Name                   July 2017

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

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  PASSporT 'div' Claim  . . . . . . . . . . . . . . . . . . . .   3
   4.  Using 'div' in SIP  . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  Authentication Service Behavior . . . . . . . . . . . . .   5
     4.2.  Verification Service Behavior . . . . . . . . . . . . . .   6
   5.  Extending 'div' . . . . . . . . . . . . . . . . . . . . . . .   6
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   9.  Informative References  . . . . . . . . . . . . . . . . . . .   7
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   PASSporT [I-D.ietf-stir-passport] is a token format based on JWT
   [RFC7519] for conveying cryptographically-signed information about
   the people involved in personal communications; it is used with STIR
   [I-D.ietf-stir-rfc4474bis] to convey a signed assertion of the
   identity of the participants in real-time communications established
   via a protocol like SIP.  This specification extends PASSporT to
   include an indication that a call has been diverted from its
   originally destination to a new one.

   Although the STIR problem statement [RFC7340] is focused on
   preventing the impersonation of the caller's identity, which is a
   common enabler for threats such as robocalling and voicemail hacking
   on the telephone network today, it also provides a signature over the
   called number as the authentication service sees it.  As
   [I-D.ietf-stir-rfc4474bis] Section 12.1 describes, this protection
   over the contents of the To header field is intended to prevent a
   class of cut-and-paste attacks.  If Alice calls Bob, for example, Bob
   might attempt to cut-and-paste the Identity header field in Alice's
   INVITE into a new INVITE that Bob sends to Carol, and thus be able to
   fool Carol into thinking the call came from Alice and not Bob. With
   the signature over the To header field value, the INVITE Carol sees
   will clearly have been destined originally for Bob, and thus Carol
   can view the INVITE as suspect.

   However, as [I-D.ietf-stir-rfc4474bis] Section 12.1.1 points out, it
   is difficult for Carol to confirm or reject these suspicions based on
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