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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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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