STIR Out-of-Band Architecture and Use Cases
draft-ietf-stir-oob-04

Document Type Active Internet-Draft (stir WG)
Last updated 2019-03-31 (latest revision 2019-03-11)
Replaces draft-rescorla-stir-fallback
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Network Working Group                                        E. Rescorla
Internet-Draft                                                   Mozilla
Intended status: Standards Track                             J. Peterson
Expires: September 12, 2019                                      Neustar
                                                          March 11, 2019

              STIR Out-of-Band Architecture and Use Cases
                       draft-ietf-stir-oob-04.txt

Abstract

   The PASSporT format defines a token that can be carried by signaling
   protocols, including SIP, to cryptographically attest the identify of
   callers.  Not all telephone calls use Internet signaling protocols,
   however, and some calls use them for only part of their signaling
   path.  This document describes use cases that require the delivery of
   PASSporT objects outside of the signaling path, and defines
   architectures and semantics to provide this functionality.

Status of This Memo

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   This Internet-Draft will expire on September 12, 2019.

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
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   (https://trustee.ietf.org/license-info) in effect on the date of
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   carefully, as they describe your rights and restrictions with respect
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Rescorla & Peterson    Expires September 12, 2019               [Page 1]
Internet-Draft              STIR Out-of-Band                  March 2019

   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
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  Operating Environments  . . . . . . . . . . . . . . . . . . .   4
   4.  Dataflows . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . . . .   6
     5.1.  Case 1: VoIP to PSTN Call . . . . . . . . . . . . . . . .   6
     5.2.  Case 2: Two Smart PSTN endpoints  . . . . . . . . . . . .   7
     5.3.  Case 3: PSTN to VoIP Call . . . . . . . . . . . . . . . .   7
     5.4.  Case 4: Gateway Out-of-band . . . . . . . . . . . . . . .   8
     5.5.  Case 5: Enterprise Call Center  . . . . . . . . . . . . .   8
   6.  Storing and Retrieving PASSporTs  . . . . . . . . . . . . . .   9
     6.1.  Storage . . . . . . . . . . . . . . . . . . . . . . . . .  10
     6.2.  Retrieval . . . . . . . . . . . . . . . . . . . . . . . .  11
   7.  Solution Architecture . . . . . . . . . . . . . . . . . . . .  11
     7.1.  Credentials and Phone Numbers . . . . . . . . . . . . . .  12
     7.2.  Call Flow . . . . . . . . . . . . . . . . . . . . . . . .  12
     7.3.  Security Analysis . . . . . . . . . . . . . . . . . . . .  13
     7.4.  Substitution Attacks  . . . . . . . . . . . . . . . . . .  13
     7.5.  Rate Control for CPS Storage  . . . . . . . . . . . . . .  14
   8.  Authentication and Verification Service Behavior for Out-of-
       Band  . . . . . . . . . . . . . . . . . . . . . . . . . . . .  15
     8.1.  Authentication Service  . . . . . . . . . . . . . . . . .  16
     8.2.  Verification Service  . . . . . . . . . . . . . . . . . .  17
     8.3.  Gateway Placement Services  . . . . . . . . . . . . . . .  18
   9.  Example HTTPS Interface to the CPS  . . . . . . . . . . . . .  18
   10. CPS Discovery . . . . . . . . . . . . . . . . . . . . . . . .  20
   11. Credential Lookup . . . . . . . . . . . . . . . . . . . . . .  21
   12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  22
   13. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  22
   14. Security Considerations . . . . . . . . . . . . . . . . . . .  22
   15. Informative References  . . . . . . . . . . . . . . . . . . .  22
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  24

1.  Introduction

   The STIR problem statement [RFC7340] describes widespread problems
   enabled by impersonation in the telephone network, including illegal
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