STIR                                                            C. Wendt
Internet-Draft                                                   Comcast
Intended status: Standards Track                             J. Peterson
Expires: March 13, 30, 2017                                     Neustar Inc.
                                                      September 9, 26, 2016


                  Personal Assertion Token
                      draft-ietf-stir-passport-07 (PASSporT)


   This document defines a canonical string object or 'token' including
   a digital signature method for verifying the author of the token, their
   authority to author the token creating and the information asserted in the
   token, minimally, the validating a token
   that cryptographically verifies an originating identity identity, or 'persona' corresponding
   specifically to more
   generally a URI or telephone number representing the originator of 'personal communications', or
   signalled communications between a set of parties with identities.
   personal communications.  The PASSporT token is cryptographically
   signed to protect the integrity of the identify identity the originator of a personal communications
   session (e.g. the telephone number or URI) and to
   verify the assertion of the identity information at the destination.
   The cryptographic signature is defined with the intention that it can
   confidently verify the originating persona even when the signature is
   sent to the destination party over an insecure channel.  PASSporT is
   particularly useful for many personal communications applications
   over IP networks and other multi-hop interconnection scenarios where
   the originating and destination parties may not have a direct trusted

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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  PASSporT Token Overview . . . . . . . . . . . . . . . . . . .   4   3
   3.  PASSporT Header . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  "typ" (Type) Header Parameter . . . . . . . . . . . . . .   4
     3.2.  "alg" (Algorithm) Header Parameter  . . . . . . . . . . .   4
     3.3.  "x5u" (X.509 URL) Header Parameter  . . . . . . . . . . .   5
     3.4.  Example PASSporT header . . . . . . . . . . . . . . . . .   5
   4.  PASSporT Payload  . . . . . . . . . . . . . . . . . . . . . .   5
     4.1.  JWT defined claims  . . . . . . . . . . . . . . . . . . .   5
       4.1.1.  "iat" - Issued At claim . . . . . . . . . . . . . . .   6   5
     4.2.  PASSporT specific claims  . . . . . . . . . . . . . . . .   6
       4.2.1.  Originating and Destination Identity Claims . . . . .   6  "tn"
       4.2.2.  "mky" - Telephone Number identity  . . . . . . Media Key claim . .   7  "uri" - URI identity . . . . . . . . . . . . .   8
   5.  PASSporT Signature  .   7  Future identity forms . . . . . . . . . . . . . .   7  Examples . . . . . .   9
   6.  Compact form of PASSporT  . . . . . . . . . . . . . .   7
       4.2.2.  "mky" - Media Key claim . . . .   9
     6.1.  Example Compact form PASSporT Token . . . . . . . . . . .   8
   5.  10
   7.  Extending PASSporT Signature  . . . . . . . . .  . . . . . . . . . . . .   9
   6.  Extending PASSporT . . . . . . . . .  10
     7.1.  "ppt" (PASSporT) header parameter . . . . . . . . . . . .   9
     6.1.  "ppt" (PASSporT)  11
     7.2.  Example extended PASSporT header parameter  . . . . . . . . . . . .  10
     6.2.  11
     7.3.  Extended PASSporT Claims  . . . . . . . . . . . . . . . .  10
   7.  11
   8.  Deterministic JSON Serialization  . . . . . . . . . . . . . .  11
     7.1.  12
     8.1.  Example PASSport deterministic JSON form  . . . . . . . .  11
   8.  12
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
     8.1.  14
     9.1.  Avoidance of replay and cut and paste attacks . . . . . .  12
     8.2.  14
     9.2.  Solution Considerations . . . . . . . . . . . . . . . . .  13
     8.3.  Privacy  14
   10. IANA Considerations . . . . . . . . . . . . . . . . .  13
   9.  IANA Considerations . . . . .  15
     10.1.  Media Type Registration  . . . . . . . . . . . . . . . .  13
     9.1.  15
       10.1.1.  Media Type Registration . . . . Registry Contents Additions Requested . .  15
     10.2.  JSON Web Token Claims Registration . . . . . . . . . . .  13
       9.1.1.  Media Type  16
       10.2.1.  Registry Contents Additions Requested  . .  13
     9.2. . . . . .  16
     10.3.  JSON Web Token Claims Registration Signature and Encryption Header Parameter
            Registry . . . . . . . . . . .  15
       9.2.1. . . . . . . . . . . . . .  16
       10.3.1.  Registry Contents Additions Requested  . . . . . . . .  15
   10.  16
   11. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  15
   11.  17
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  15
     11.1.  17
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  16
     11.2.  17
     12.2.  Informative References . . . . . . . . . . . . . . . . .  17  18
   Appendix A.  Example ES256 based PASSporT JWS Serialization and
                Signature  . .  17 . . . . . . . . . . . . . . . . . . .  18
     A.1.  X.509 Private Key Certificate for Example ES256 Example** . . . . . . . . .  19 .  20
     A.2.  X.509 Public Key Certificate for Example ES256 Example**  . . . . . . . . . .  19  20
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  19  20

1.  Introduction

   In today's IP-enabled telecommunications world, there is a growing
   concern about the ability to trust incoming invitations for
   communications sessions, including video, voice and messaging.
   [RFC7340] messaging
   [RFC7340].  As an example, modern telephone networks provide the
   ability to spoof the calling party telephone number for many
   legitimate purposes including providing network features and services
   on the behalf of a legitimate telephone number.  However, as we have
   seen, bad actors have taken advantage of this ability for
   illegitimate and fraudulent purposes meant to trick telephone users
   to believe they are someone they are not.  This problem can be
   extended to many emerging forms of personal communications.

   This document defines a method for creating and validating a token
   that cryptographically verifies an originating identity, or more
   generally a URI or telephone number representing the originator of
   personal communications.  Through extensions defined in this
   document, in Section 5.2, 7, other information relevant to the personal
   communications can also be added to the token.  The goal of PASSporT
   is to provide a common framework for signing originating identity
   related information in an extensible way.  Additionally, this
   functionality is independent of any specific personal communications
   signaling call logic, so that the assertion of originating identity
   related information can be implemented in a flexible way and can be
   used in applications including end-to-end applications that require
   different signaling protocols or gateways between different
   communications systems.  It is anticipated that signaling protocol
   specific guidance will be provided in other related documents and
   specifications to specify how to use and transport PASSporT tokens,
   however this is intentionally out of scope for this document.

   [I-D.ietf-stir-rfc4474bis] provides details of the use of PASSporT
   within the SIP [RFC3261] signaling protocol for the signing and
   verification of telephone numbers. numbers and SIP URIs.

2.  PASSporT Token Overview

   JSON Web Token (JWT) [RFC7519] and JSON Web Signature (JWS) [RFC7515]
   and related specifications define a standard token format that can be
   used as a way of encapsulating claimed or asserted information with
   an associated digital signature using X.509 based certificates.  JWT
   provides a set of claims in JSON format that can conveniently
   accommodate asserted originating identity information and is easily
   extensible for extension mechanisms defined below.  Additionally, JWS
   provides a path for updating methods and cryptographic algorithms
   used for the associated digital signatures.

   JWS defines the use of JSON data structures in a specified canonical
   format for signing data corresponding to JOSE header, JWS Payload,
   and JWS Signature.  JWT defines a set of claims that are represented
   by specified key value pairs which can be extended with custom keys
   for specific applications.  The next sections define the header and
   claims that MUST be minimally used with JWT and JWS for PASSporT.

3.  PASSporT Header

   The JWS token header is a JOSE header header, [RFC7515] Section 4, that
   defines the type and encryption algorithm used in the token.

   PASSporT header should include, at a minimum, the following header parameters
   defined the in the next three subsections.

3.1.  "typ" (Type) Header Parameter

   The "typ" (Type) Header Parameter is defined in JWS [RFC7515]
   Section 4.1.9. to declare the media type of the complete JWS.

   For PASSporT Token the "typ" header MUST be the string "passport".
   This represents that the encoded token is a JWT of type passport.

3.2.  "alg" (Algorithm) Header Parameter

   The "alg" (Algorithm) Header Parameter is defined in JWS [RFC7515]
   Section 4.1.1.  This definition includes the ability to specify the
   use of a cryptographic algorithm for the signature part of the JWS.
   It also refers to a list of defined "alg" values as part of a
   registry established by JSON Web Algorithms (JWA) [RFC7518] and
   defined in
   Section 3.1.

   For the creation and verification of PASSporT tokens and their
   digital signatures ES256 signatures, implementations MUST be implemented support ES256 as defined in
   JWA [RFC7518] Section 3.4
   Note that JWA defines 3.4.  Implementations MAY support other
   algorithms registered in the JSON Web Signature and Encryption
   Algorithms registry created by [RFC7518].  The contents of that
   registry may be utilized or updated in the future depending on cryptographic
   strength requirements guided by current security best practice.  The
   mandatory-to-support algorithm for PASSporT tokens may likewise be
   updated in future updates to this document.

3.3.  "x5u" (X.509 URL) Header Parameter

   As defined in JWS [RFC7515] Section 4.1.5., the "x5u" header
   parameter defines a URI [RFC3986] referring to the resource for the
   X.509 public key certificate or certificate chain [RFC5280]
   corresponding to the key used to digitally sign the JWS.  Generally,
   as defined in JWS [RFC7515] section 4.1.5, this would correspond to
   an HTTPS or DNSSEC resource using integrity protection.

3.4.  Example PASSporT header

   An example of the header, would be the following, including the
   specified passport type, ES256 algorithm, and a URI referencing the
   network location of the certificate needed to validate the PASSporT


4.  PASSporT Payload

   The token claims consist of the information which needs to be
   verified at the destination party.  These claims follow the
   definition of a JWT claim [RFC7519] Section 4 and be are encoded as
   defined by the JWS Payload [RFC7515] Section 3.

   PASSporT defines the use of a standard JWT defined claim as well as
   custom claims corresponding to the two parties associated with
   personal communications, the originator and destination as detailed

   Any claim key values outside the US-ASCII range should be encoded
   using percent encoding as described in section Section 2.1 of [RFC3986], case
   normalized as described in of [RFC3986].

4.1.  JWT defined claims

4.1.1.  "iat" - Issued At claim

   The JSON claim MUST include the "iat" [RFC7519] Section 4.1.6 defined
   claim Issued At.  As defined this the "iat" should be set to the date and
   time of issuance of the JWT and MUST the origination of the personal
   communications.  The time value should be of the format defined in
   [RFC7519] Section 2 NumericDate.  This is included for securing the
   token against replay and cut and paste attacks, as explained further
   in the security considerations in
   section 6. Section 9.

4.2.  PASSporT specific claims

4.2.1.  Originating and Destination Identity Claims

   PASSporT defines claims that convey the identity of the origination
   and destination of personal communications.  Origination in the
   context of PASSporT and for a given application's use of PASSporT is
   the point in the network that has the authority to assert the callers
   identity.  This authority is represented in PASSporT by the
   certificate holder and is signed at the applications choice of
   authoritative point(s) in the network, for example, at a device that
   has authenticated with a user, or at a network entity with an
   authenticated trust relationship with that device and its it's user.
   Destination represents the intended destination of the personal
   communications, i.e. the identity(s) being called by the caller, caller.  The
   destination point(s) determined by the application must need to have the
   capability to verify the PASSporT token and the digital signature.
   The PASSporT associated certificate is used to validate the authority
   of the originating signer, generally via a certificate chain to the
   trust anchor for that application.

   The origination and destination identities are represented by two
   claims that are required for PASSporT, the "orig" and "dest" claims.
   Both "orig" and "dest" MUST have claims where the key represents an
   identity type and the value is the identity string, both defined in
   subsequent subsections.  Currently, these identities can be
   represented as either telephone numbers or Uniform Resource
   Indicators (URIs).

   The "orig" JSON object MUST only have one key value pair representing
   the asserted identity of any type (currently either "tn" or "uri") of
   the originator of the personal communications signaling.

   The "dest" JSON object MUST have at least have one key value pair,
   but could have multiple identity types (i.e. "tn" and/or "uri") but
   only one of each.  If both "tn" and "uri" are included, the JSON
   object should list the "tn" array first and the "uri" array second.
   Within the "tn" and "uri" arrays, the identity strings should be put
   in lexicographical order including the scheme-specific portion of the
   URI characters.  Additionally, in the case of "dest" only, the
   identity type key value MUST be an array signaled by standard JSON
   brackets, even when there is a single identity value in the identity
   type key value.  "tn" - Telephone Number identity

   If the originating or destination identity is a telephone number, the
   key representing the identity MUST be "tn".

   Telephone Number strings for "tn" MUST be canonicalized according to
   the procedures specified in [I-D.ietf-stir-rfc4474bis] Section 8.3.  "uri" - URI identity

   If any of the originating or destination identities is of the form
   URI, as defined in [RFC3986], the key representing the identity MUST
   be "uri" URI form of the identity.  Future identity forms

   We recognize that in the future there may be other standard
   mechanisms for representing identities.  The "orig" and "dest" claims
   currently support "tn" and "uri" but could be extended in the future
   to allow for other identity types with new IANA registered unique
   types to represent these forms.  Examples

   Single Originator, with telephone number identity +12155551212, to
   Single Destination, with URI identity '',


   Single Originator, with telephone number identity +12155551212, to
   Multiple Destination Identities, with telephone number identity
   +12125551212 and two URI identities, and, example:


4.2.2.  "mky" - Media Key claim

   Some protocols that use PASSporT may also want to protect media
   security keys delivered within their signaling in order to bind those
   keys to the identities established in the signaling layers.  The
   "mky" is an optional PASSporT claim defining the assertion of media
   key fingerprints carried in SDP [RFC4566] via the "a=fingerprint"
   attribute [RFC4572] Section 5.  This claim can support either a
   single or multiple fingerprints appearing in a single SDP body
   corresponding to one or more media streams offered.  The "mky" claim
   MUST be formated formatted in a JSON form including the "alg" and "dig" keys
   with the corresponding algorithm and hexadecimal values.  If there are is
   more that than one fingerprint values value associated with different media
   streams in SDP, the fingerprint values MUST be constructed as a JSON
   array denoted by bracket characters.  For the "dig" key value, the
   hash value MUST be the hexadecimal value without any colons.  The
   "mky" array MUST order the JSON objects containing both "alg" and
   "dig" key values in lexicographic order of the "alg" string first
   followed by the corresponding lexicographic order of the "dig" string
   values.  Within each of those objects the JSON keys MUST have "alg"
   first and "dig" second.

   An example claim with "mky" claim is as follows:

   For an SDP offer that includes the following fingerprint values,

   a=fingerprint:sha-256 4A:AD:B9:B1:3F:82:18:3B:54:02:12:DF:3E:
   a=fingerprint:sha-256 02:1A:CC:54:27:AB:EB:9C:53:3F:3E:4B:65:
       2E:7D:46:3F:54:42:CD:54:F1:7A:03:A2:7D:F9:B0:7F:46:19:B2 02:1A:CC:54:27:AB:EB:9C:53:3F:3E:4B:65

   the PASSporT Payload object would be:


5.  PASSporT Signature

   The signature of the PASSporT is created as specified by JWS
   [RFC7515] Section 5.1 Steps 1 through 6.  PASSporT MUST use the JWS
   Protected Header.  For the JWS Payload and the JWS Protected Header,
   the lexicographic ordering and white space rules described above, and
   JSON serialization rules in Section 6 8 of this document MUST be

   Appendix A of this document has a detailed example of how to follow
   the steps to create the JWS Signature.

   JWS [RFC7515] Section 5.1 Step 7 JWS JSON serialization is not
   supported for PASSporT.

   JWS [RFC7515] Section 5.1 Step 8 describes the method to create the
   final JWS Compact Serialization form of the PASSporT Token.

6.  Extending PASSporT  Compact form of PASSporT includes the bare minimum set

   For a using protocol of claims needed to securely
   assert PASSporT, the originating identity and support PASSporT Claims as well as the secure properties
   PASSporT Header may include redundant or default information that
   could be reconstructed at the destination based on information
   provided in various parts of the signaling protocol transporting the PASSporT object.
   In this document.  JWT supports a straight
   forward way case, it may be advantageous to add additional claims by simply adding new claim key
   pairs. have a more compact form of
   PASSporT can be extended beyond to save the defined base set transmission of
   claims the bytes needed to represent other information requiring assertion or
   validation beyond
   the originating identity itself as needed.

6.1.  "ppt" (PASSporT) header parameter

   For extension and claims.

   We define the compact form of the base set PASSporT token, in the spirit of claims
   form defined in this document, a
   new JWS header parameter "ppt" MUST be used [RFC7515] Appendix F, with a unique string.
   Any the use of '..', two
   periods to represent the header and claim objects being removed,
   followed by PASSporT extension should be signature as defined in Section 5, and the need
   for the destination to reconstruct the header and claim objects in
   order to verify the signature.

   In order to construct the Compact form of the PASSporT string, the
   procedure described in Section 5 with the exception of Step 8
   described in JWS [RFC7515] Section 5.1.  This step would be replaced
   by the following construction of the compact form of PASSporT,
   '..' || BASE64URL(JWS Signature).

   The using protocol of the compact form of PASSporT MUST be
   accompanied by a specification
   describing for how the PASSporT extension header and claims objects
   can be reconstructed from information in the string signaling protocol being

6.1.  Example Compact form PASSporT Token

   The compact form of the following example token (with line breaks
   between period used for readability purposes only)


   would be as follows (with line breaks between period used for
   readability purposes only)


7.  Extending PASSporT

   PASSporT includes the bare minimum set of claims needed to securely
   assert the originating identity and support the secure properties
   discussed in various parts of this document.  JWT supports a straight
   forward way to add additional claims by simply adding new claim key
   pairs.  PASSporT can be extended beyond the defined base set of
   claims to represent other information requiring assertion or
   validation beyond the originating identity itself as needed.

7.1.  "ppt" (PASSporT) header string parameter

   Any using protocol can extend the payload of PASSporT with additional
   JWT claims.  JWT claims are managed by an existing IANA registry as
   defined in [RFC7519] Section 10.1.  Implementations of PASSporT MUST
   support the baseline claims defined in Section 4.2, and MAY support
   extended claims.  If it is necessary for an extension to PASSporT to
   require that defines any a relying party support a particular extended claim or
   set of claims in the PASSporT object, it can do so by specifying a
   "ppt" element for the PASSporT JOSE header.  All values of "ppt" need
   to be defined in a specification which associates the new value of
   the "ppt" element with the required claims and behaviors.  Relying
   parties MUST fail to validate PASSporT objects containing an
   unsupported "ppt".

   Using protocols that would extend carry the base
   set compact form of PASSporT, defined in
   Section 6, instead of the full form MUST use only mandatory
   extensions signaled with "ppt" - if a using protocol were to add
   additional optional claims to a PASSporT object it carried in compact
   form, relying parties would have no way to reconstruct the token.
   Moreover, using protocols that support the compact form of PASSporT. PASSporT
   MUST have some field to signal "ppt" to relying parties, as the
   compact form of PASSporT omits the JOSE header.

7.2.  Example extended PASSporT header

   An example header with a PASSporT extension type of "foo" is as



7.3.  Extended PASSporT Claims

   Specifications that define extensions to the PASSporT mechanism MUST
   explicitly specify what claims they include beyond the base set of
   claims from this document, the order in which they will appear, and
   any further information necessary to implement the extension.  All
   extensions MUST include the baseline JWT PASSporT claim elements
   specified in Section 3; 4; claims may only be appended to the claims
   object specified; they can never be removed or re-ordered.
   Specifying new claims follows the baseline JWT procedures ([RFC7519]
   Section 10.1).  Understanding an extension or new claims defined by
   the extension on the destination verification of the PASSporT token
   is optional.  The creator of a PASSporT object cannot assume that
   destination systems will understand any given extension.
   Verification of PASSporT tokens by destination systems that do
   support an extension may then trigger appropriate application-level
   behavior in the presence of an extension; authors of extensions
   should provide appropriate extension-specific guidance to application
   developers on this point.

   An example set of extended claims, extending the first example in
   Section using "bar" as the newly defined claim would be as

       "bar":"beyond all recognition"


8.  Deterministic JSON Serialization

   JSON, as a canonical format, can include spaces, spaces and line breaks breaks, and
   key value pairs can occur in any order and order.  It is therefore makes it, from a non-
   deterministic string format, non-deterministic. format.  In order to make the digital signature
   verification work deterministically, the JSON representation of the PASSporT Header and Claims, particularly if
   PASSporT is used across multiple signaling environments, specifically
   JWS Protected Header object and JWS Payload object MUST be computed
   as follows.

   The JSON object MUST follow the rules for the construction of the
   thumbprint of a JSON Web Key (JWK) as defined in [RFC7638] Section 3
   Step 1 only.  Step 2 MUST NOT should not be performed; as noted in JWK this is
   still a legal JWK object.

   The PASSporT header and claim direct members MUST follow the
   lexicographical ordering rules.  Any top level JSON members that
   contain JSON objects or arrays, such as "dest" or "mky" MUST follow
   their own lexicographical ordering and whitespace and line break
   rules for the sub-elements.  This includes any header or claims
   defined in future specifications using PASSporT.


8.1.  Example PASSport deterministic JSON form

   This section demonstrate the deterministic JSON serialization for the
   example PASSporT Payload shown in Section 4.2.2.

   The initial JSON object is shown here:


   The parent members of the JSON object are as follows:

   o  "dest"

   o  "orig"

   o  "iat"

   o  "mky"

   Their lexicographic order is:

   o  "dest"

   o  "iat"

   o  "mky"

   o  "orig"

   The final constructed deterministic JSON serialization
   representation, with whitespace and line breaks removed, (with line
   breaks used for display purposes only) is:



9.  Security Considerations


9.1.  Avoidance of replay and cut and paste attacks

   There are a number of security considerations for use of the token
   for avoidance of replay and cut and paste attacks.  PASSporT tokens
   SHOULD only be sent with other application level protocol information
   (e.g. for SIP an INVITE as defined in [RFC3261]).  In order to make
   the token signature unique to a specific origination of personal
   communications there should be a link between various information
   provided in the token and information provided by the application level protocol information.  This information (e.g.
   for SIP an INVITE as defined in [RFC3261]) corresponding to the
   required fields in the token.  A uniqueness specified of the set of token
   claims and token signature is constructed using the originating
   identity being asserted with the 'orig' claim along with the the
   following two claims:

   o  'iat' claim should correspond to a date/time the message was
      originated.  It should also be within a relative time that is
      reasonable for clock drift and transmission time characteristics
      associated with the application using the PASSporT token.
      Therefore, validation of the token should consider date and time
      correlation, which could be influenced by signaling protocol
      specific use and network time differences.

   o  'dest' claim is included to prevent the valid re-use of a
      previously originated message to send to another destination


9.2.  Solution Considerations

   The use of PASSporT tokens based on the validation of the digital
   signature and the associated certificate requires consideration of
   the authentication and authority or reputation of the signer to
   attest to the identity being asserted.  It  The following considerations
   should be recognized that
   the when using PASSporT: * The use of this token
   should not, in it's own right, be considered a full solution for
   absolute non-repudiation of the identity being asserted.  It can and often is the case that  * In many
   applications, the end user that the asserted identity represents and
   signer are may not be one in the same.  However,
   applications that use PASSporT should ensure  For example, when a service
   provider signs and validates the signer is in an
   authoritative position to represent token on the behalf of the user
   consuming the service, the provider MUST have an authenticated and authenticate
   secure relationship with the end user onto or the communications network device initiating and should be
   terminating the responsible
   party for protecting communications signaling.  * Applications that use
   PASSporT should ensure the destination party from potential identity
   spoofing in addition to other abuse verification of the communications network
   outside of PASSporT.

8.3.  Privacy Considerations

   Because PASSporT explicitly signature includes claims of identifiers the
   means of parties
   involved in communications, date and times, and potentially other
   call detail, care should be taken outside verifying the signer is authoritative through the use of traditional protected or
   private telephony communications paths where there may be concerns
   about exposing information to either unintended an
   application or illegitimate
   actors.  These identifiers are often exposed through many
   communications signaling protocols as service specific set of today, but appropriate
   precautions should be taken.

9. common trust anchors for the

10.  IANA Considerations


10.1.  Media Type Registration


10.1.1.  Media Type Registry Contents Additions Requested

   This section registers the "application/passport" media type
   [RFC2046] in the "Media Types" registry in the manner described in
   [RFC6838], which can be used to indicate that the content is a
   PASSporT defined JWT and JWS.

   o  Type name: application

   o  Subtype name: passport

   o  Required parameters: n/a

   o  Optional parameters: n/a

   o  Encoding considerations: 8bit; application/passport values outside
      the US-ASCII range are encoded using percent encoding as described
      in section Section 2.1 of RFC 3986 [RFC3986] (some values may be the empty string),
      each separated from the next by a single period ('.') character.

   o  Security considerations: See the Security Considerations section
      Section of RFC 7515. [RFC7515].

   o  Interoperability considerations: n/a

   o  Published specification: draft-ietf-stir-passport-05 [RFCThis]

   o  Applications that use this media type: STIR and other applications
      that require identity related assertion

   o  Fragment identifier considerations: n/a

   o  Additional information:


      Magic number(s): n/a

      * File extension(s): n/a

      * Macintosh file type
      code(s): n/a

   o  Person and & email address to contact for further information: Chris

   o  Intended usage: COMMON

   o  Restrictions on usage: none
   o  Author: Chris Wendt,

   o  Change Controller: IESG

   o  Provisional registration?  No


10.2.  JSON Web Token Claims Registration


10.2.1.  Registry Contents Additions Requested

   o  Claim Name: "orig"

   o  Claim Description: Originating Identity String

   o  Change Controller: IESG

   o  Specification Document(s): Section 3.2 4.2.1 of draft-ietf-stir-
      passport-05 [RFCThis]

   o  Claim Name: "dest"

   o  Claim Description: Destination Identity String

   o  Change Controller: IESG

   o  Specification Document(s): Section 3.2 4.2.1 of draft-ietf-stir-
      passport-05 [RFCThis]

   o  Claim Name: "mky"

   o  Claim Description: Media Key Fingerprint String

   o  Change Controller: IESG

   o  Specification Document(s): Section 3.2 4.2.2 of draft-ietf-stir-

10. [RFCThis]

10.3.  JSON Web Signature and Encryption Header Parameter Registry

10.3.1.  Registry Contents Additions Requested

   Header Parameter Name: "ppt"

   o  Header Parameter Description: PASSporT extension identifier

   o  Header Parameter Usage Location(s): JWS

   o  Change Controller: IESG

   o  Specification Document(s): Section 7.1 of [RFCThis]

11.  Acknowledgements

   Particular thanks to members of the ATIS and SIP Forum NNI Task Group
   including Jim McEchern, Martin Dolly, Richard Shockey, John Barnhill,
   Christer Holmberg, Victor Pascual Avila, Mary Barnes, Eric Burger for
   their review, ideas, and contributions also thanks to Henning
   Schulzrinne, Russ Housley, Alan Johnston, Richard Barnes, Mark
   Miller, Ted Hardie, Dave Crocker, Robert Sparks for valuable feedback
   on the technical and security aspects of the document.  Additional
   thanks to Harsha Bellur for assistance in coding the example tokens.


12.  References

12.1.  Normative References

              Peterson, J., Jennings, C., Rescorla, E., and C. Wendt,
              "Authenticated Identity Management in the Session
              Initiation Protocol (SIP)", draft-ietf-stir-rfc4474bis-12
              (work in progress), August September 2016.

   [RFC2046]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part Two: Media Types", RFC 2046,
              DOI 10.17487/RFC2046, November 1996,

   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,

   [RFC4566]  Handley, M., Jacobson, V., and C. Perkins, "SDP: Session
              Description Protocol", RFC 4566, DOI 10.17487/RFC4566,
              July 2006, <>.

   [RFC4572]  Lennox, J., "Connection-Oriented Media Transport over the
              Transport Layer Security (TLS) Protocol in the Session
              Description Protocol (SDP)", RFC 4572,
              DOI 10.17487/RFC4572, July 2006,

   [RFC6838]  Freed, N., Klensin, J., and T. Hansen, "Media Type
              Specifications and Registration Procedures", BCP 13,
              RFC 6838, DOI 10.17487/RFC6838, January 2013,

   [RFC7515]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web
              Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
              2015, <>.

   [RFC7518]  Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
              DOI 10.17487/RFC7518, May 2015,

   [RFC7519]  Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
              (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,

   [RFC7638]  Jones, M. and N. Sakimura, "JSON Web Key (JWK)
              Thumbprint", RFC 7638, DOI 10.17487/RFC7638, September
              2015, <>.


12.2.  Informative References

   [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,

   [RFC5280]  Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
              Housley, R., and W. Polk, "Internet X.509 Public Key
              Infrastructure Certificate and Certificate Revocation List
              (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,

   [RFC7340]  Peterson, J., Schulzrinne, H., and H. Tschofenig, "Secure
              Telephone Identity Problem Statement and Requirements",
              RFC 7340, DOI 10.17487/RFC7340, September 2014,

Appendix A.  Example ES256 based PASSporT JWS Serialization and

   For PASSporT, there will always be a JWS with the following members:

   o  "protected", with the value BASE64URL(UTF8(JWS Protected Header))

   o  "payload", with the value BASE64URL (JWS Payload)

   o  "signature", with the value BASE64URL(JWS Signature)
   This example will follow the steps in JWS [RFC7515] Section 5.1,
   steps 1-6 and 8 and incorporates the additional serialization steps
   required for PASSporT.

   Step 1 for JWS references the JWS Payload, an example PASSporT
   Payload is as follows:


   This would be serialized to the form (with line break used for
   display purposes only):


   Step 2 Computes the BASE64URL(JWS Payload) producing this value (with
   line break used for display purposes only):



   For Step 3, an example PASSporT Protected Header comprising the JOSE
   Header is as follows:


   This would be serialized to the form (with line break used for
   display purposes only):



   Step 4 Performs the BASE64URL(UTF8(JWS Protected Header)) operation
   and encoding produces this value (with line break used for display
   purposes only):

   Step 5 and Step 6 performs the computation of the digital signature
   of the PASSporT Signing Input ASCII(BASE64URL(UTF8(JWS Protected
   Header)) || '.' || BASE64URL(JWS Payload)) using ES256 as the
   algorithm and the BASE64URL(JWS Signature).



   Step 8 describes how to create the final PASSporT token,
   concatenating the values in the order Header.Payload.Signature with
   period ('.') characters.  For the above example values this would
   produce the following (with line breaks between period used for
   readability purposes only):



A.1.  X.509 Private Key Certificate for Example ES256 Example**

   -----END EC PRIVATE KEY-----

A.2.  X.509 Public Key Certificate for Example ES256 Example**

   -----BEGIN PUBLIC KEY-----
   -----END PUBLIC KEY-----

Authors' Addresses

   Chris Wendt
   One Comcast Center
   Philadelphia, PA  19103

   Jon Peterson
   Neustar Inc.
   1800 Sutter St Suite 570
   Concord, CA  94520