draft-ietf-oauth-proof-of-possession-03.txt   draft-ietf-oauth-proof-of-possession-04.txt 
OAuth Working Group M. Jones OAuth Working Group M. Jones
Internet-Draft Microsoft Internet-Draft Microsoft
Intended status: Standards Track J. Bradley Intended status: Standards Track J. Bradley
Expires: January 7, 2016 Ping Identity Expires: February 29, 2016 Ping Identity
H. Tschofenig H. Tschofenig
ARM Limited ARM Limited
July 6, 2015 August 28, 2015
Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs) Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs)
draft-ietf-oauth-proof-of-possession-03 draft-ietf-oauth-proof-of-possession-04
Abstract Abstract
This specification defines how to express a declaration in a JSON Web This specification defines how to express a declaration in a JSON Web
Token (JWT) that the presenter of the JWT possesses a particular key Token (JWT) that the presenter of the JWT possesses a particular key
and that the recipient can cryptographically confirm proof-of- and that the recipient can cryptographically confirm proof-of-
possession of the key by the presenter. This property is also possession of the key by the presenter. This property is also
sometimes described as the presenter being a holder-of-key. sometimes described as the presenter being a holder-of-key.
Status of this Memo Status of this Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 7, 2016. This Internet-Draft will expire on February 29, 2016.
Copyright Notice Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 4 1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Representations for Proof-of-Possession Keys . . . . . . . . . 4 3. Representations for Proof-of-Possession Keys . . . . . . . . . 4
3.1. Representation for an Asymmetric Proof-of-Possession 3.1. Confirmation Claim . . . . . . . . . . . . . . . . . . . . 5
Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. Representation of an Asymmetric Proof-of-Possession Key . 5
3.2. Representation for an Encrypted Symmetric 3.3. Representation of an Encrypted Symmetric
Proof-of-Possession Key . . . . . . . . . . . . . . . . . 5 Proof-of-Possession Key . . . . . . . . . . . . . . . . . 6
3.3. Representation of a Key ID for a Proof-of-Possession 3.4. Representation of a Key ID for a Proof-of-Possession
Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Key . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.4. Confirmation . . . . . . . . . . . . . . . . . . . . . . . 7 3.5. Representation of a URL for a Proof-of-Possession Key . . 8
3.5. Specifics Intentionally Not Specified . . . . . . . . . . 7 3.6. Specifics Intentionally Not Specified . . . . . . . . . . 8
4. Security Considerations . . . . . . . . . . . . . . . . . . . 8 4. Security Considerations . . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 5. Privacy Considerations . . . . . . . . . . . . . . . . . . . . 9
5.1. JSON Web Token Claims Registration . . . . . . . . . . . . 9 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
5.1.1. Registry Contents . . . . . . . . . . . . . . . . . . 10 6.1. JSON Web Token Claims Registration . . . . . . . . . . . . 11
5.2. JWT Confirmation Methods Registry . . . . . . . . . . . . 10 6.1.1. Registry Contents . . . . . . . . . . . . . . . . . . 11
5.2.1. Registration Template . . . . . . . . . . . . . . . . 10 6.2. JWT Confirmation Methods Registry . . . . . . . . . . . . 11
5.2.2. Initial Registry Contents . . . . . . . . . . . . . . 10 6.2.1. Registration Template . . . . . . . . . . . . . . . . 11
6. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 6.2.2. Initial Registry Contents . . . . . . . . . . . . . . 12
6.1. Normative References . . . . . . . . . . . . . . . . . . . 11 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6.2. Informative References . . . . . . . . . . . . . . . . . . 11 7.1. Normative References . . . . . . . . . . . . . . . . . . . 12
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 12 7.2. Informative References . . . . . . . . . . . . . . . . . . 13
Appendix B. Document History . . . . . . . . . . . . . . . . . . 12 Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 13 Appendix B. Document History . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction 1. Introduction
This specification defines how to express a declaration in a JSON Web This specification defines how to express a declaration in a JSON Web
Token (JWT) [JWT] that the presenter of the JWT possesses a Token (JWT) [JWT] that the presenter of the JWT possesses a
particular key and that the recipient can cryptographically confirm particular key and that the recipient can cryptographically confirm
proof-of-possession of the key by the presenter. This property is proof-of-possession of the key by the presenter. This property is
also sometimes described as the presenter being a holder-of-key. also sometimes described as the presenter being a holder-of-key. See
[I-D.ietf-oauth-pop-architecture] for a further discussion of key
confirmation.
Envision the following two use cases. The first use case describes Envision the following two use cases. The first use case describes
the use of a symmetric proof-of-possession key and the second use the use of a symmetric proof-of-possession key and the second use
case uses an asymmetric proof-of-possession key. case uses an asymmetric proof-of-possession key.
An issuer generates a JWT and places an encrypted symmetric key An issuer generates a JWT and places an encrypted symmetric key
inside the newly introduced confirmation claim. This symmetric key inside the newly introduced confirmation claim. This symmetric key
is encrypted with a key known only to the issuer and the recipient. is encrypted with a key known only to the issuer and the recipient.
The entire JWT is then integrity protected by the issuer. The JWT is The entire JWT is then integrity protected by the issuer. The JWT is
then sent to the presenter. Since the presenter is unable to obtain then sent to the presenter. Since the presenter is unable to obtain
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modifications. The JWT is then sent to the presenter. When the modifications. The JWT is then sent to the presenter. When the
presenter needs to present the JWT to the recipient, it also needs to presenter needs to present the JWT to the recipient, it also needs to
demonstrate possession of the private key. The presenter, for demonstrate possession of the private key. The presenter, for
example, uses the private key in a TLS exchange with the recipient or example, uses the private key in a TLS exchange with the recipient or
signs a nonce with the private key. The recipient is able to verify signs a nonce with the private key. The recipient is able to verify
that it is interacting with the genuine presenter by extracting the that it is interacting with the genuine presenter by extracting the
public key from the confirmation claim of the JWT (after verifying public key from the confirmation claim of the JWT (after verifying
the digital signature of the JWT) and utilizing it with the private the digital signature of the JWT) and utilizing it with the private
key in the TLS exchange or checking the nonce signature. key in the TLS exchange or checking the nonce signature.
In both cases the JWT may contain other claims that are needed by the In both cases, the JWT may contain other claims that are needed by
application. the application.
1.1. Notational Conventions 1.1. Notational Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in RFC "OPTIONAL" in this document are to be interpreted as described in RFC
2119 [RFC2119]. 2119 [RFC2119].
Unless otherwise noted, all the protocol parameter names and values Unless otherwise noted, all the protocol parameter names and values
are case sensitive. are case sensitive.
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These terms are defined by this specification: These terms are defined by this specification:
Issuer Issuer
Party that creates the JWT and binds the proof-of-possession key Party that creates the JWT and binds the proof-of-possession key
to it. to it.
Presenter Presenter
Party that proves possession of a private key (for asymmetric key Party that proves possession of a private key (for asymmetric key
cryptography) or secret key (for symmetric key cryptography) to a cryptography) or secret key (for symmetric key cryptography) to a
recipient. The presenter may be the issuer or a party distinct recipient.
from the issuer.
Recipient Recipient
Party that receives the JWT containing the proof-of-possession key Party that receives the JWT containing the proof-of-possession key
information from the presenter. information from the presenter.
3. Representations for Proof-of-Possession Keys 3. Representations for Proof-of-Possession Keys
The issuer of a JWT declares that the presenter possesses a The issuer of a JWT declares that the presenter possesses a
particular key and that the recipient can cryptographically confirm particular key and that the recipient can cryptographically confirm
proof-of-possession of the key by the presenter by including a "cnf" proof-of-possession of the key by the presenter by including a "cnf"
(confirmation) claim in the JWT whose value is a JSON object, with a (confirmation) claim in the JWT whose value is a JSON object.
JSON object containing a "jwk" (JSON Web Key) member, a "jwe" (JSON Members in the JSON object identify the proof-of-possession key.
Web Encryption) member, or a "kid" (key ID) member identifying the
key.
The presenter can be identified in one of several ways by the JWT, The presenter can be identified in one of several ways by the JWT,
depending upon the application requirements. If the JWT contains a depending upon the application requirements. If the JWT contains a
"sub" (subject) claim, the presenter is normally the subject "sub" (subject) claim, the presenter is normally the subject
identified by the JWT. (In some applications, the subject identifier identified by the JWT. (In some applications, the subject identifier
will be relative to the issuer identified by the "iss" (issuer) will be relative to the issuer identified by the "iss" (issuer)
claim.) If the JWT contains no "sub" (subject) claim, the presenter claim.) If the JWT contains no "sub" (subject) claim, the presenter
is normally the issuer identified by the JWT using the "iss" (issuer) is normally the issuer identified by the JWT using the "iss" (issuer)
claim. The case in which the presenter is the subject of the JWT is claim. The case in which the presenter is the subject of the JWT is
analogous to SAML 2.0 [OASIS.saml-core-2.0-os] SubjectConfirmation analogous to SAML 2.0 [OASIS.saml-core-2.0-os] SubjectConfirmation
usage. At least one of the "sub" and "iss" claims MUST be present in usage. At least one of the "sub" and "iss" claims MUST be present in
the JWT. Some use cases may require that both be present. the JWT. Some use cases may require that both be present.
Another means used by some applications to identify the presenter is Another means used by some applications to identify the presenter is
an explicit claim, such as the "azp" (authorized party) claim defined an explicit claim, such as the "azp" (authorized party) claim defined
by OpenID Connect [OpenID.Core]. Ultimately, the means of by OpenID Connect [OpenID.Core]. Ultimately, the means of
identifying the presenter is application-specific, as is the means of identifying the presenter is application-specific, as is the means of
confirming possession of the key that is communicated. confirming possession of the key that is communicated.
3.1. Representation for an Asymmetric Proof-of-Possession Key 3.1. Confirmation Claim
The "cnf" (confirmation) claim is used in the JWT to contain members
used to identify the proof-of-possession key. Other members of the
"cnf" object may be defined because a proof-of-possession key may not
be the only means of confirming the authenticity of the token. This
is analogous to the SAML 2.0 [OASIS.saml-core-2.0-os]
SubjectConfirmation element, in which a number of different subject
confirmation methods can be included, including proof-of-possession
key information. When a recipient receives a "cnf" claim with a
member that it does not understand, it MUST ignore that member.
This specification establishes the IANA "JWT Confirmation Methods"
registry for these members in Section 6.2 and registers the members
defined by this specification. Other specifications can register
other members used for confirmation, including other members for
conveying proof-of-possession keys, possibly using different key
representations.
Note that if an application needs to represent multiple proof-of-
possession keys in the same JWT, one way for it to achieve this is to
use other claim names, in addition to "cnf", to hold the additional
proof-of-possession key information. These claims could use the same
syntax and semantics as the "cnf" claim.
3.2. Representation of an Asymmetric Proof-of-Possession Key
When the key held by the presenter is an asymmetric private key, the When the key held by the presenter is an asymmetric private key, the
"jwk" member is a JSON Web Key (JWK) [JWK] representing the "jwk" member is a JSON Web Key (JWK) [JWK] representing the
corresponding asymmetric public key. The following example corresponding asymmetric public key. The following example
demonstrates such a declaration in the JWT Claims Set of a JWT: demonstrates such a declaration in the JWT Claims Set of a JWT:
{ {
"iss": "https://server.example.com", "iss": "https://server.example.com",
"aud": "https://client.example.org", "aud": "https://client.example.org",
"exp": "1361398824", "exp": "1361398824",
"nbf": "1360189224",
"cnf":{ "cnf":{
"jwk":{ "jwk":{
"kty": "EC", "kty": "EC",
"use": "sig", "use": "sig",
"crv": "P-256", "crv": "P-256",
"x": "18wHLeIgW9wVN6VD1Txgpqy2LszYkMf6J8njVAibvhM", "x": "18wHLeIgW9wVN6VD1Txgpqy2LszYkMf6J8njVAibvhM",
"y": "-V4dS4UaLMgP_4fY4j8ir7cl1TXlFdAgcx55o7TkcSA" "y": "-V4dS4UaLMgP_4fY4j8ir7cl1TXlFdAgcx55o7TkcSA"
} }
} }
} }
The JWK MUST contain the required key members for a JWK of that key The JWK MUST contain the required key members for a JWK of that key
type and MAY contain other JWK members, including the "kid" (key ID) type and MAY contain other JWK members, including the "kid" (key ID)
member. member.
3.2. Representation for an Encrypted Symmetric Proof-of-Possession Key The "jwk" member MAY also be used for a JWK representing a symmetric
key, provided that the JWT is encrypted so that the key is not
revealed to unintended parties. If the JWT is not encrypted, the
symmetric key MUST be encrypted as described below.
3.3. Representation of an Encrypted Symmetric Proof-of-Possession Key
When the key held by the presenter is a symmetric key, the "jwe" When the key held by the presenter is a symmetric key, the "jwe"
member is an encrypted JSON Web Key (JWK) [JWK] encrypted to a key member is an encrypted JSON Web Key (JWK) [JWK] encrypted to a key
known to the recipient using the JWE Compact Serialization containing known to the recipient using the JWE Compact Serialization containing
the symmetric key. The rules for encrypting a JWK are found in the symmetric key. The rules for encrypting a JWK are found in
Section 7 of the JSON Web Key [JWK] specification. Section 7 of the JSON Web Key [JWK] specification.
The following example illustrates a symmetric key that could The following example illustrates a symmetric key that could
subsequently be encrypted for use in the "jwe" member: subsequently be encrypted for use in the "jwe" member:
{ {
"kty": "oct", "kty": "oct",
"alg": "HS256", "alg": "HS256",
"k": "ZoRSOrFzN_FzUA5XKMYoVHyzff5oRJxl-IXRtztJ6uE" "k": "ZoRSOrFzN_FzUA5XKMYoVHyzff5oRJxl-IXRtztJ6uE"
} }
The UTF-8 [RFC3629] encoding of this JWK would be used as the JWE The UTF-8 [RFC3629] encoding of this JWK is used as the JWE Plaintext
Plaintext when encrypting the key. when encrypting the key.
The following example is a JWE Header that could be used when The following example is a JWE Header that could be used when
encrypting this key: encrypting this key:
{ {
"alg": "RSA1_5", "alg": "RSA-OAEP",
"enc": "A128CBC-HS256" "enc": "A128CBC-HS256"
} }
The following example JWT Claims Set of a JWT illustrates the use of The following example JWT Claims Set of a JWT illustrates the use of
an encrypted symmetric key as the "jwe" member value: an encrypted symmetric key as the "jwe" member value:
{ {
"iss": "https://server.example.com", "iss": "https://server.example.com",
"sub": "24400320", "sub": "24400320",
"aud": "s6BhdRkqt3", "aud": "s6BhdRkqt3",
"nonce": "n-0S6_WzA2Mj", "nonce": "n-0S6_WzA2Mj",
"exp": 1311281970, "exp": 1311281970,
"iat": 1311280970, "iat": 1311280970,
"cnf":{ "cnf":{
"jwe": "jwe":
"eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0. "eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkExMjhDQkMtSFMyNTYifQ.
(remainder of JWE omitted for brevity)" (remainder of JWE omitted for brevity)"
} }
} }
3.3. Representation of a Key ID for a Proof-of-Possession Key 3.4. Representation of a Key ID for a Proof-of-Possession Key
The proof-of-possession key can also be identified by the use of a The proof-of-possession key can also be identified by the use of a
Key ID instead of communicating the actual key, provided the Key ID instead of communicating the actual key, provided the
recipient is able to obtain the identified key using the Key ID. In recipient is able to obtain the identified key using the Key ID. In
this case, the issuer of a JWT declares that the presenter possesses this case, the issuer of a JWT declares that the presenter possesses
a particular key and that the recipient can cryptographically confirm a particular key and that the recipient can cryptographically confirm
proof-of-possession of the key by the presenter by including a "cnf" proof-of-possession of the key by the presenter by including a "cnf"
(confirmation) claim in the JWT whose value is a JSON object, with (confirmation) claim in the JWT whose value is a JSON object, with
the JSON object containing a "kid" (key ID) member identifying the the JSON object containing a "kid" (key ID) member identifying the
key. key.
The following example demonstrates such a declaration in the JWT The following example demonstrates such a declaration in the JWT
Claims Set of a JWT: Claims Set of a JWT:
{ {
"iss": "https://server.example.com", "iss": "https://server.example.com",
"aud": "https://client.example.org", "aud": "https://client.example.org",
"exp": "1361398824", "exp": "1361398824",
"nbf": "1360189224",
"cnf":{ "cnf":{
"kid": "dfd1aa97-6d8d-4575-a0fe-34b96de2bfad" "kid": "dfd1aa97-6d8d-4575-a0fe-34b96de2bfad"
} }
} }
3.4. Confirmation The content of the "kid" value is application specific. For
instance, some applications may choose to use a JWK Thumbprint
The "cnf" (confirmation) claim is used in the JWT to contain the [JWK.Thumbprint] value as the "kid" value.
"jwk", "jwe", or "kid" member because a proof-of-possession key may
not be the only means of confirming the authenticity of the token.
This is analogous to the SAML 2.0 [OASIS.saml-core-2.0-os]
SubjectConfirmation element, in which a number of different subject
confirmation methods can be included, including proof-of-possession
key information. When a recipient receives a "cnf" claim with a
member that it does not understand, it MUST ignore that member.
This specification establishes the IANA "JWT Confirmation Methods" 3.5. Representation of a URL for a Proof-of-Possession Key
registry for these members in Section 5.2 and registers the "jwk",
"jwe", and "kid" members within the registry. Other specifications
can register other members used for confirmation, including members
for conveying other proof-of-possession keys, possibly using
different key representations.
3.5. Specifics Intentionally Not Specified The proof-of-possession key can be passed by reference instead of
being passed by value. This is done using the "jku" (JWK Set URL)
member. Its value is a URI [RFC3986] that refers to a resource for a
set of JSON-encoded public keys represented as a JWK Set [JWK], one
of which is the proof-of-possession key. If there are multiple keys
in the referenced JWK Set document, a "kid" member MUST also be
included, with the referenced key's JWK also containing the same
"kid" value.
The protocol used to acquire the resource MUST provide integrity
protection; an HTTP GET request to retrieve the JWK Set MUST use
Transport Layer Security (TLS) [RFC5246]; and the identity of the
server MUST be validated, as per Section 6 of RFC 6125 [RFC6125].
The following example demonstrates such a declaration in the JWT
Claims Set of a JWT:
{
"iss": "https://server.example.com",
"sub": "17760704",
"aud": "https://client.example.org",
"exp": "1440804813",
"cnf":{
"jku": "https://keys.example.net/pop-keys.json",
"kid": "2015-08-28"
}
}
3.6. Specifics Intentionally Not Specified
Proof-of-possession is typically demonstrated by having the presenter Proof-of-possession is typically demonstrated by having the presenter
sign a value determined by the recipient using the key possessed by sign a value determined by the recipient using the key possessed by
the presenter. This value is sometimes called a "nonce" or a the presenter. This value is sometimes called a "nonce" or a
"challenge". "challenge".
The means of communicating the nonce and the nature of its contents The means of communicating the nonce and the nature of its contents
are intentionally not described in this specification, as different are intentionally not described in this specification, as different
protocols will communicate this information in different ways. protocols will communicate this information in different ways.
Likewise, the means of communicating the signed nonce is also not Likewise, the means of communicating the signed nonce is also not
specified, as this is also protocol-specific. specified, as this is also protocol-specific.
Note that another means of proving possession of the key when it is a Note that another means of proving possession of the key when it is a
symmetric key is to encrypt the key to the recipient. The means of symmetric key is to encrypt the key to the recipient. The means of
obtaining a key for the recipient is likewise protocol-specific. obtaining a key for the recipient is likewise protocol-specific.
For an example specification that uses the mechanisms defined in this For examples using the mechanisms defined in this specification, see
document, see [I-D.ietf-oauth-pop-architecture]. [I-D.ietf-oauth-pop-architecture].
4. Security Considerations 4. Security Considerations
All of the normal security issues, especially in relationship to All of the normal security issues, especially in relationship to
comparing URIs and dealing with unrecognized values, that are comparing URIs and dealing with unrecognized values, that are
discussed in JWT [JWT] also apply here. discussed in JWT [JWT] also apply here.
In addition, proof-of-possession introduces its own unique security In addition, proof-of-possession introduces its own unique security
issues. Possessing the key is only valuable if it is kept secret. issues. Possessing the key is only valuable if it is kept secret.
Appropriate means must be used to ensure that unintended parties do Appropriate means must be used to ensure that unintended parties do
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those not only require integrity protection, but also confidentiality those not only require integrity protection, but also confidentiality
protection. protection.
A recipient may not understand the newly introduced "cnf" claim and A recipient may not understand the newly introduced "cnf" claim and
may consequently treat it as a bearer token. While this is a may consequently treat it as a bearer token. While this is a
legitimate concern, it is outside the scope of this specification, legitimate concern, it is outside the scope of this specification,
since demonstration the possession of the key associated with the since demonstration the possession of the key associated with the
"cnf" claim is not covered by this specification. For more details, "cnf" claim is not covered by this specification. For more details,
please consult [I-D.ietf-oauth-pop-architecture]. please consult [I-D.ietf-oauth-pop-architecture].
5. IANA Considerations 5. Privacy Considerations
A proof-of-possession key can be used as a correlation handle if the
same key is used with multiple parties. Thus, for privacy reasons,
it is recommended that different proof-of-possession keys be used
when interacting with different parties.
6. IANA Considerations
The following registration procedure is used for all the registries The following registration procedure is used for all the registries
established by this specification. established by this specification.
Values are registered on a Specification Required [RFC5226] basis Values are registered on a Specification Required [RFC5226] basis
after a three-week review period on the oauth-pop-reg-review@ietf.org after a three-week review period on the oauth-pop-reg-review@ietf.org
mailing list, on the advice of one or more Designated Experts. mailing list, on the advice of one or more Designated Experts.
However, to allow for the allocation of values prior to publication, However, to allow for the allocation of values prior to publication,
the Designated Experts may approve registration once they are the Designated Experts may approve registration once they are
satisfied that such a specification will be published. [[ Note to the satisfied that such a specification will be published. [[ Note to the
skipping to change at page 9, line 45 skipping to change at page 11, line 5
list. list.
It is suggested that multiple Designated Experts be appointed who are It is suggested that multiple Designated Experts be appointed who are
able to represent the perspectives of different applications using able to represent the perspectives of different applications using
this specification, in order to enable broadly-informed review of this specification, in order to enable broadly-informed review of
registration decisions. In cases where a registration decision could registration decisions. In cases where a registration decision could
be perceived as creating a conflict of interest for a particular be perceived as creating a conflict of interest for a particular
Expert, that Expert should defer to the judgment of the other Expert, that Expert should defer to the judgment of the other
Experts. Experts.
5.1. JSON Web Token Claims Registration 6.1. JSON Web Token Claims Registration
This specification registers the "cnf" claim in the IANA JSON Web This specification registers the "cnf" claim in the IANA "JSON Web
Token Claims registry defined in [JWT]. Token Claims" registry [IANA.JWT.Claims] established by [JWT].
5.1.1. Registry Contents 6.1.1. Registry Contents
o Claim Name: "cnf" o Claim Name: "cnf"
o Claim Description: Confirmation o Claim Description: Confirmation
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): Section 3.4 of this document o Specification Document(s): Section 3.1 of [[ this document ]]
5.2. JWT Confirmation Methods Registry 6.2. JWT Confirmation Methods Registry
This specification establishes the IANA "JWT Confirmation Methods" This specification establishes the IANA "JWT Confirmation Methods"
registry for JWT "cnf" member values. The registry records the registry for JWT "cnf" member values. The registry records the
confirmation method member and a reference to the specification that confirmation method member and a reference to the specification that
defines it. defines it.
5.2.1. Registration Template 6.2.1. Registration Template
Confirmation Method Value: Confirmation Method Value:
The name requested (e.g., "kid"). Because a core goal of this The name requested (e.g., "kid"). Because a core goal of this
specification is for the resulting representations to be compact, specification is for the resulting representations to be compact,
it is RECOMMENDED that the name be short -- not to exceed 8 it is RECOMMENDED that the name be short -- not to exceed 8
characters without a compelling reason to do so. This name is characters without a compelling reason to do so. This name is
case-sensitive. Names may not match other registered names in a case-sensitive. Names may not match other registered names in a
case-insensitive manner unless the Designated Experts state that case-insensitive manner unless the Designated Experts state that
there is a compelling reason to allow an exception. there is a compelling reason to allow an exception.
skipping to change at page 10, line 45 skipping to change at page 12, line 5
For Standards Track RFCs, list the "IESG". For others, give the For Standards Track RFCs, list the "IESG". For others, give the
name of the responsible party. Other details (e.g., postal name of the responsible party. Other details (e.g., postal
address, email address, home page URI) may also be included. address, email address, home page URI) may also be included.
Specification Document(s): Specification Document(s):
Reference to the document or documents that specify the parameter, Reference to the document or documents that specify the parameter,
preferably including URIs that can be used to retrieve copies of preferably including URIs that can be used to retrieve copies of
the documents. An indication of the relevant sections may also be the documents. An indication of the relevant sections may also be
included but is not required. included but is not required.
5.2.2. Initial Registry Contents 6.2.2. Initial Registry Contents
o Confirmation Method Value: "jwk" o Confirmation Method Value: "jwk"
o Confirmation Method Description: JSON Web Key Representing Public o Confirmation Method Description: JSON Web Key Representing Public
Key Key
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): Section 3.1 of [[ this document ]] o Specification Document(s): Section 3.2 of [[ this document ]]
o Confirmation Method Value: "jwe" o Confirmation Method Value: "jwe"
o Confirmation Method Description: Encrypted JSON Web Key o Confirmation Method Description: Encrypted JSON Web Key
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): Section 3.2 of [[ this document ]] o Specification Document(s): Section 3.3 of [[ this document ]]
o Confirmation Method Value: "kid" o Confirmation Method Value: "kid"
o Confirmation Method Description: Key Identifier o Confirmation Method Description: Key Identifier
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): Section 3.3 of [[ this document ]] o Specification Document(s): Section 3.4 of [[ this document ]]
6. References o Confirmation Method Value: "jku"
o Confirmation Method Description: JWK Set URL
o Change Controller: IESG
o Specification Document(s): Section 3.5 of [[ this document ]]
6.1. Normative References 7. References
7.1. Normative References
[IANA.JWT.Claims]
IANA, "JSON Web Token Claims",
<http://www.iana.org/assignments/jwt>.
[JWE] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)", [JWE] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)",
RFC 7516, May 2015, RFC 7516, May 2015,
<http://www.rfc-editor.org/info/rfc7516>. <http://www.rfc-editor.org/info/rfc7516>.
[JWK] Jones, M., "JSON Web Key (JWK)", RFC 7517, May 2015, [JWK] Jones, M., "JSON Web Key (JWK)", RFC 7517, May 2015,
<http://www.rfc-editor.org/info/rfc7517>. <http://www.rfc-editor.org/info/rfc7517>.
[JWT] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token [JWT] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, May 2015, (JWT)", RFC 7519, May 2015,
<http://www.rfc-editor.org/info/rfc7519>. <http://www.rfc-editor.org/info/rfc7519>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO
10646", STD 63, RFC 3629, November 2003. 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629,
November 2003, <http://www.rfc-editor.org/info/rfc3629>.
[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,
<http://www.rfc-editor.org/info/rfc3986>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
6.2. Informative References [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/
RFC5246, August 2008,
<http://www.rfc-editor.org/info/rfc5246>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125,
March 2011, <http://www.rfc-editor.org/info/rfc6125>.
7.2. Informative References
[I-D.ietf-oauth-pop-architecture] [I-D.ietf-oauth-pop-architecture]
Hunt, P., Richer, J., Mills, W., Mishra, P., and H. Hunt, P., Richer, J., Mills, W., Mishra, P., and H.
Tschofenig, "OAuth 2.0 Proof-of-Possession (PoP) Security Tschofenig, "OAuth 2.0 Proof-of-Possession (PoP) Security
Architecture", draft-ietf-oauth-pop-architecture-01 (work Architecture", draft-ietf-oauth-pop-architecture-01 (work
in progress), March 2015. in progress), March 2015.
[JWK.Thumbprint]
Jones, M. and N. Sakimura, "JSON Web Key (JWK)
Thumbprint", draft-ietf-jose-jwk-thumbprint (work in
progress), July 2015, <http://tools.ietf.org/html/
draft-ietf-jose-jwk-thumbprint-08>.
[OASIS.saml-core-2.0-os] [OASIS.saml-core-2.0-os]
Cantor, S., Kemp, J., Philpott, R., and E. Maler, Cantor, S., Kemp, J., Philpott, R., and E. Maler,
"Assertions and Protocol for the OASIS Security Assertion "Assertions and Protocol for the OASIS Security Assertion
Markup Language (SAML) V2.0", OASIS Standard saml-core- Markup Language (SAML) V2.0", OASIS Standard saml-core-
2.0-os, March 2005. 2.0-os, March 2005.
[OpenID.Core] [OpenID.Core]
Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
C. Mortimore, "OpenID Connect Core 1.0", November 2014, C. Mortimore, "OpenID Connect Core 1.0", November 2014,
<http://openid.net/specs/openid-connect-core-1_0.html>. <http://openid.net/specs/openid-connect-core-1_0.html>.
Appendix A. Acknowledgements Appendix A. Acknowledgements
The authors wish to thank Brian Campbell, James Manger, Justin The authors wish to thank Brian Campbell, James Manger, Justin
Richer, and Nat Sakimura for their reviews of the specification. Richer, and Nat Sakimura for their reviews of the specification.
Appendix B. Document History Appendix B. Document History
[[ to be removed by the RFC Editor before publication as an RFC ]] [[ to be removed by the RFC Editor before publication as an RFC ]]
-04
o Allowed the use of "jwk" for symmetric keys when the JWT is
encrypted.
o Added the "jku" (JWK Set URL) member.
o Added privacy considerations.
o Reordered sections so that the "cnf" (confirmation) claim is
defined before it is used.
o Noted that applications can define new claim names, in addition to
"cnf", to represent additional proof-of-possession keys, using the
same representation as "cnf".
o Applied wording clarifications suggested by Nat Sakimura.
-03 -03
o Separated the "jwk" and "jwe" confirmation members; the former o Separated the "jwk" and "jwe" confirmation members; the former
represents a public key as a JWK and the latter represents a represents a public key as a JWK and the latter represents a
symmetric key as a JWE encrypted JWK. symmetric key as a JWE encrypted JWK.
o Changed the title to indicate that a proof-of-possession key is o Changed the title to indicate that a proof-of-possession key is
being communicated. being communicated.
o Updated language that formerly assumed that the issuer was an o Updated language that formerly assumed that the issuer was an
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