rfc9449.original   rfc9449.txt 
Web Authorization Protocol D. Fett Internet Engineering Task Force (IETF) D. Fett
Internet-Draft Authlete Request for Comments: 9449 Authlete
Intended status: Standards Track B. Campbell Category: Standards Track B. Campbell
Expires: 15 October 2023 Ping Identity ISSN: 2070-1721 Ping Identity
J. Bradley J. Bradley
Yubico Yubico
T. Lodderstedt T. Lodderstedt
yes.com Tuconic
M. Jones M. Jones
independent Self-Issued Consulting
D. Waite D. Waite
Ping Identity Ping Identity
13 April 2023 September 2023
OAuth 2.0 Demonstrating Proof-of-Possession at the Application Layer OAuth 2.0 Demonstrating Proof of Possession (DPoP)
(DPoP)
draft-ietf-oauth-dpop-16
Abstract Abstract
This document describes a mechanism for sender-constraining OAuth 2.0 This document describes a mechanism for sender-constraining OAuth 2.0
tokens via a proof-of-possession mechanism on the application level. tokens via a proof-of-possession mechanism on the application level.
This mechanism allows for the detection of replay attacks with access This mechanism allows for the detection of replay attacks with access
and refresh tokens. and refresh tokens.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
and may be updated, replaced, or obsoleted by other documents at any (IETF). It represents the consensus of the IETF community. It has
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Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on 15 October 2023. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
https://www.rfc-editor.org/info/rfc9449.
Copyright Notice Copyright Notice
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction
1.1. Conventions and Terminology . . . . . . . . . . . . . . . 4 1.1. Conventions and Terminology
2. Objectives . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Objectives
3. Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Concept
4. DPoP Proof JWTs . . . . . . . . . . . . . . . . . . . . . . . 8 4. DPoP Proof JWTs
4.1. The DPoP HTTP Header . . . . . . . . . . . . . . . . . . 8 4.1. The DPoP HTTP Header
4.2. DPoP Proof JWT Syntax . . . . . . . . . . . . . . . . . . 9 4.2. DPoP Proof JWT Syntax
4.3. Checking DPoP Proofs . . . . . . . . . . . . . . . . . . 11 4.3. Checking DPoP Proofs
5. DPoP Access Token Request . . . . . . . . . . . . . . . . . . 12 5. DPoP Access Token Request
5.1. Authorization Server Metadata . . . . . . . . . . . . . . 15 5.1. Authorization Server Metadata
5.2. Client Registration Metadata . . . . . . . . . . . . . . 15 5.2. Client Registration Metadata
6. Public Key Confirmation . . . . . . . . . . . . . . . . . . . 16 6. Public Key Confirmation
6.1. JWK Thumbprint Confirmation Method . . . . . . . . . . . 16 6.1. JWK Thumbprint Confirmation Method
6.2. JWK Thumbprint Confirmation Method in Token 6.2. JWK Thumbprint Confirmation Method in Token Introspection
Introspection . . . . . . . . . . . . . . . . . . . . . . 17 7. Protected Resource Access
7. Protected Resource Access . . . . . . . . . . . . . . . . . . 18 7.1. The DPoP Authentication Scheme
7.1. The DPoP Authentication Scheme . . . . . . . . . . . . . 19 7.2. Compatibility with the Bearer Authentication Scheme
7.2. Compatibility with the Bearer Authentication Scheme . . . 22 7.3. Client Considerations
7.3. Client Considerations . . . . . . . . . . . . . . . . . . 24 8. Authorization Server-Provided Nonce
8. Authorization Server-Provided Nonce . . . . . . . . . . . . . 24 8.1. Nonce Syntax
8.1. Nonce Syntax . . . . . . . . . . . . . . . . . . . . . . 26 8.2. Providing a New Nonce Value
8.2. Providing a New Nonce Value . . . . . . . . . . . . . . . 26 9. Resource Server-Provided Nonce
9. Resource Server-Provided Nonce . . . . . . . . . . . . . . . 27 10. Authorization Code Binding to a DPoP Key
10. Authorization Code Binding to DPoP Key . . . . . . . . . . . 28 10.1. DPoP with Pushed Authorization Requests
10.1. DPoP with Pushed Authorization Requests . . . . . . . . 28 11. Security Considerations
11. Security Considerations . . . . . . . . . . . . . . . . . . . 29 11.1. DPoP Proof Replay
11.1. DPoP Proof Replay . . . . . . . . . . . . . . . . . . . 29 11.2. DPoP Proof Pre-generation
11.2. DPoP Proof Pre-Generation . . . . . . . . . . . . . . . 30 11.3. DPoP Nonce Downgrade
11.3. DPoP Nonce Downgrade . . . . . . . . . . . . . . . . . . 31 11.4. Untrusted Code in the Client Context
11.4. Untrusted Code in the Client Context . . . . . . . . . . 31 11.5. Signed JWT Swapping
11.5. Signed JWT Swapping . . . . . . . . . . . . . . . . . . 32 11.6. Signature Algorithms
11.6. Signature Algorithms . . . . . . . . . . . . . . . . . . 32 11.7. Request Integrity
11.7. Request Integrity . . . . . . . . . . . . . . . . . . . 32 11.8. Access Token and Public Key Binding
11.8. Access Token and Public Key Binding . . . . . . . . . . 33 11.9. Authorization Code and Public Key Binding
11.9. Authorization Code and Public Key Binding . . . . . . . 33 11.10. Hash Algorithm Agility
11.10. Hash Algorithm Agility . . . . . . . . . . . . . . . . . 34 11.11. Binding to Client Identity
11.11. Binding to Client Identity . . . . . . . . . . . . . . . 34 12. IANA Considerations
12.1. OAuth Access Token Types Registration
12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 34 12.2. OAuth Extensions Error Registration
12.1. OAuth Access Token Type Registration . . . . . . . . . . 34 12.3. OAuth Parameters Registration
12.2. OAuth Extensions Error Registration . . . . . . . . . . 35 12.4. HTTP Authentication Schemes Registration
12.3. OAuth Parameters Registration . . . . . . . . . . . . . 35 12.5. Media Type Registration
12.4. HTTP Authentication Scheme Registration . . . . . . . . 35 12.6. JWT Confirmation Methods Registration
12.5. Media Type Registration . . . . . . . . . . . . . . . . 36 12.7. JSON Web Token Claims Registration
12.6. JWT Confirmation Methods Registration . . . . . . . . . 36 12.7.1. "nonce" Registration Update
12.7. JSON Web Token Claims Registration . . . . . . . . . . . 36 12.8. Hypertext Transfer Protocol (HTTP) Field Name Registration
12.7.1. "nonce" Registry Update . . . . . . . . . . . . . . 37 12.9. OAuth Authorization Server Metadata Registration
12.8. HTTP Message Header Field Names Registration . . . . . . 38 12.10. OAuth Dynamic Client Registration Metadata
12.9. OAuth Authorization Server Metadata Registration . . . . 38 13. References
12.10. OAuth Dynamic Client Registration Metadata . . . . . . . 38 13.1. Normative References
13. Normative References . . . . . . . . . . . . . . . . . . . . 38 13.2. Informative References
14. Informative References . . . . . . . . . . . . . . . . . . . 40 Acknowledgements
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 43 Authors' Addresses
Appendix B. Document History . . . . . . . . . . . . . . . . . . 44
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 48
1. Introduction 1. Introduction
DPoP (for Demonstrating Proof-of-Possession at the Application Layer) Demonstrating Proof of Possession (DPoP) is an application-level
is an application-level mechanism for sender-constraining OAuth mechanism for sender-constraining OAuth [RFC6749] access and refresh
[RFC6749] access and refresh tokens. It enables a client to prove tokens. It enables a client to prove the possession of a public/
the possession of a public/private key pair by including a DPoP private key pair by including a DPoP header in an HTTP request. The
header in an HTTP request. The value of the header is a JSON Web value of the header is a JSON Web Token (JWT) [RFC7519] that enables
Token (JWT) [RFC7519] that enables the authorization server to bind the authorization server to bind issued tokens to the public part of
issued tokens to the public part of a client's key pair. Recipients a client's key pair. Recipients of such tokens are then able to
of such tokens are then able to verify the binding of the token to verify the binding of the token to the key pair that the client has
the key pair that the client has demonstrated that it holds via the demonstrated that it holds via the DPoP header, thereby providing
DPoP header, thereby providing some assurance that the client some assurance that the client presenting the token also possesses
presenting the token also possesses the private key. In other words, the private key. In other words, the legitimate presenter of the
the legitimate presenter of the token is constrained to be the sender token is constrained to be the sender that holds and proves
that holds and can prove possession of the private part of the key possession of the private part of the key pair.
pair.
The mechanism specified herein can be used in cases where other The mechanism specified herein can be used in cases where other
methods of sender-constraining tokens that utilize elements of the methods of sender-constraining tokens that utilize elements of the
underlying secure transport layer, such as [RFC8705] or underlying secure transport layer, such as [RFC8705] or
[I-D.ietf-oauth-token-binding], are not available or desirable. For [TOKEN-BINDING], are not available or desirable. For example, due to
example, due to a sub-par user experience of TLS client a sub-par user experience of TLS client authentication in user agents
authentication in user agents and a lack of support for HTTP token and a lack of support for HTTP token binding, neither mechanism can
binding, neither mechanism can be used if an OAuth client is an be used if an OAuth client is an application that is dynamically
application that is dynamically downloaded and executed in a web downloaded and executed in a web browser (sometimes referred to as a
browser (sometimes referred to as a "single-page application"). "single-page application"). Additionally, applications that are
Applications installed and run directly on a user's device are installed and run directly on a user's device are well positioned to
another example well positioned to benefit from DPoP-bound tokens to benefit from DPoP-bound tokens that guard against the misuse of
guard against misuse of tokens by a compromised or malicious tokens by a compromised or malicious resource. Such applications
resource. Such applications often have dedicated protected storage often have dedicated protected storage for cryptographic keys.
for cryptographic keys.
DPoP can be used to sender-constrain access tokens regardless of the DPoP can be used to sender-constrain access tokens regardless of the
client authentication method employed, but DPoP itself is not used client authentication method employed, but DPoP itself is not used
for client authentication. DPoP can also be used to sender-constrain for client authentication. DPoP can also be used to sender-constrain
refresh tokens issued to public clients (those without authentication refresh tokens issued to public clients (those without authentication
credentials associated with the client_id). credentials associated with the client_id).
1.1. Conventions and Terminology 1.1. Conventions and Terminology
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 BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
This specification uses the Augmented Backus-Naur Form (ABNF) This specification uses the Augmented Backus-Naur Form (ABNF)
notation of [RFC5234]. notation of [RFC5234].
This specification uses the terms "access token", "refresh token", This specification uses the terms "access token", "refresh token",
"authorization server", "resource server", "authorization endpoint", "authorization server", "resource server", "authorization endpoint",
"authorization request", "authorization response", "token endpoint", "authorization request", "authorization response", "token endpoint",
"grant type", "access token request", "access token response", "grant type", "access token request", "access token response",
"client", "public client", and "confidential client" defined by The "client", "public client", and "confidential client" defined by "The
OAuth 2.0 Authorization Framework [RFC6749]. OAuth 2.0 Authorization Framework" [RFC6749].
The terms "request", "response", "header field", and "target URI" are The terms "request", "response", "header field", and "target URI" are
imported from [RFC9110]. imported from [RFC9110].
The terms "JOSE" and "JOSE header" are imported from [RFC7515]. The terms "JOSE" and "JOSE Header" are imported from [RFC7515].
This document contains non-normative examples of partial and complete This document contains non-normative examples of partial and complete
HTTP messages. Some examples use a single trailing backslash to HTTP messages. Some examples use a single trailing backslash to
indicate line wrapping for long values, as per [RFC8792]. The indicate line wrapping for long values, as per [RFC8792]. The
character and leading spaces on wrapped lines are not part of the character and leading spaces on wrapped lines are not part of the
value. value.
2. Objectives 2. Objectives
The primary aim of DPoP is to prevent unauthorized or illegitimate The primary aim of DPoP is to prevent unauthorized or illegitimate
skipping to change at page 5, line 27 skipping to change at line 191
This constrains the legitimate sender of the token to only the party This constrains the legitimate sender of the token to only the party
with access to the private key and gives the server receiving the with access to the private key and gives the server receiving the
token added assurances that the sender is legitimately authorized to token added assurances that the sender is legitimately authorized to
use it. use it.
Access tokens that are sender-constrained via DPoP thus stand in Access tokens that are sender-constrained via DPoP thus stand in
contrast to the typical bearer token, which can be used by any party contrast to the typical bearer token, which can be used by any party
in possession of such a token. Although protections generally exist in possession of such a token. Although protections generally exist
to prevent unintended disclosure of bearer tokens, unforeseen vectors to prevent unintended disclosure of bearer tokens, unforeseen vectors
for leakage have occurred due to vulnerabilities and implementation for leakage have occurred due to vulnerabilities and implementation
issues in other layers in the protocol or software stack (CRIME issues in other layers in the protocol or software stack (see, e.g.,
[CRIME], BREACH [BREACH], Heartbleed [Heartbleed], and the Cloudflare Compression Ratio Info-leak Made Easy (CRIME) [CRIME], Browser
parser bug [Cloudbleed] are some examples). There have also been Reconnaissance and Exfiltration via Adaptive Compression of Hypertext
numerous published token theft attacks on OAuth implementations (BREACH) [BREACH], Heartbleed [Heartbleed], and the Cloudflare parser
themselves ([GitHub.Tokens] as just one high profile example). DPoP bug [Cloudbleed]). There have also been numerous published token
provides a general defense in depth against the impact of theft attacks on OAuth implementations themselves ([GitHub.Tokens] is
unanticipated token leakage. DPoP is not, however, a substitute for just one high-profile example). DPoP provides a general defense in
a secure transport and MUST always be used in conjunction with HTTPS. depth against the impact of unanticipated token leakage. DPoP is
not, however, a substitute for a secure transport and MUST always be
used in conjunction with HTTPS.
The very nature of the typical OAuth protocol interaction The very nature of the typical OAuth protocol interaction
necessitates that the client discloses the access token to the necessitates that the client discloses the access token to the
protected resources that it accesses. The attacker model in protected resources that it accesses. The attacker model in
[I-D.ietf-oauth-security-topics] describes cases where a protected [SECURITY-TOPICS] describes cases where a protected resource might be
resource might be counterfeit, malicious or compromised and plays counterfeit, malicious, or compromised and plays received tokens
received tokens against other protected resources to gain against other protected resources to gain unauthorized access.
unauthorized access. Audience restricted access tokens (e.g., using Audience-restricted access tokens (e.g., using the JWT [RFC7519] aud
the JWT [RFC7519] aud claim) can prevent such misuse, however, doing claim) can prevent such misuse. However, doing so in practice has
so in practice has proven to be prohibitively cumbersome for many proven to be prohibitively cumbersome for many deployments (despite
deployments (even despite extensions such as [RFC8707]). Sender- extensions such as [RFC8707]). Sender-constraining access tokens is
constraining access tokens is a more robust and straightforward a more robust and straightforward mechanism to prevent such token
mechanism to prevent such token replay at a different endpoint and replay at a different endpoint, and DPoP is an accessible
DPoP is an accessible application layer means of doing so. application-layer means of doing so.
Due to the potential for cross-site scripting (XSS), browser-based Due to the potential for cross-site scripting (XSS), browser-based
OAuth clients bring to bear added considerations with respect to OAuth clients bring to bear added considerations with respect to
protecting tokens. The most straightforward XSS-based attack is for protecting tokens. The most straightforward XSS-based attack is for
an attacker to exfiltrate a token and use it themselves completely an attacker to exfiltrate a token and use it themselves completely
independent of the legitimate client. A stolen access token is used independent of the legitimate client. A stolen access token is used
for protected resource access and a stolen refresh token for for protected resource access, and a stolen refresh token is used for
obtaining new access tokens. If the private key is non-extractable obtaining new access tokens. If the private key is non-extractable
(as is possible with [W3C.WebCryptoAPI]), DPoP renders exfiltrated (as is possible with [W3C.WebCryptoAPI]), DPoP renders exfiltrated
tokens alone unusable. tokens alone unusable.
XSS vulnerabilities also allow an attacker to execute code in the XSS vulnerabilities also allow an attacker to execute code in the
context of the browser-based client application and maliciously use a context of the browser-based client application and maliciously use a
token indirectly through the client. That execution context has token indirectly through the client. That execution context has
access to utilize the signing key and thus can produce DPoP proofs to access to utilize the signing key; thus, it can produce DPoP proofs
use in conjunction with the token. At this application layer there to use in conjunction with the token. At this application layer,
is most likely no feasible defense against this threat except there is most likely no feasible defense against this threat except
generally preventing XSS, therefore it is considered out of scope for generally preventing XSS; therefore, it is considered out of scope
DPoP. for DPoP.
Malicious XSS code executed in the context of the browser-based Malicious XSS code executed in the context of the browser-based
client application is also in a position to create DPoP proofs with client application is also in a position to create DPoP proofs with
timestamp values in the future and exfiltrate them in conjunction timestamp values in the future and exfiltrate them in conjunction
with a token. These stolen artifacts can later be used independent with a token. These stolen artifacts can later be used independent
of the client application to access protected resources. To prevent of the client application to access protected resources. To prevent
this, servers can optionally require clients to include a server- this, servers can optionally require clients to include a server-
chosen value into the proof that cannot be predicted by an attacker chosen value into the proof that cannot be predicted by an attacker
(nonce). In the absence of the optional nonce, the impact of pre- (nonce). In the absence of the optional nonce, the impact of pre-
computed DPoP proofs is limited somewhat by the proof being bound to computed DPoP proofs is limited somewhat by the proof being bound to
an access token on protected resource access. Because a proof an access token on protected resource access. Because a proof
covering an access token that does not yet exist cannot feasibly be covering an access token that does not yet exist cannot feasibly be
created, access tokens obtained with an exfiltrated refresh token and created, access tokens obtained with an exfiltrated refresh token and
pre-computed proofs will be unusable. pre-computed proofs will be unusable.
Additional security considerations are discussed in Section 11. Additional security considerations are discussed in Section 11.
3. Concept 3. Concept
The main data structure introduced by this specification is a DPoP The main data structure introduced by this specification is a DPoP
proof JWT, described in detail below, which is sent as a header in an proof JWT that is sent as a header in an HTTP request, as described
HTTP request. A client uses a DPoP proof JWT to prove the possession in detail below. A client uses a DPoP proof JWT to prove the
of a private key corresponding to a certain public key. possession of a private key corresponding to a certain public key.
Roughly speaking, a DPoP proof is a signature over some data of the Roughly speaking, a DPoP proof is a signature over:
HTTP request to which it is attached, a timestamp, a unique
identifier, an optional server-provided nonce, and a hash of the * some data of the HTTP request to which it is attached,
associated access token when an access token is present within the
request. * a timestamp,
* a unique identifier,
* an optional server-provided nonce, and
* a hash of the associated access token when an access token is
present within the request.
+--------+ +---------------+ +--------+ +---------------+
| |--(A)-- Token Request ------------------->| | | |--(A)-- Token Request ------------------->| |
| Client | (DPoP Proof) | Authorization | | Client | (DPoP Proof) | Authorization |
| | | Server | | | | Server |
| |<-(B)-- DPoP-bound Access Token ----------| | | |<-(B)-- DPoP-Bound Access Token ----------| |
| | (token_type=DPoP) +---------------+ | | (token_type=DPoP) +---------------+
| | | |
| | | |
| | +---------------+ | | +---------------+
| |--(C)-- DPoP-bound Access Token --------->| | | |--(C)-- DPoP-Bound Access Token --------->| |
| | (DPoP Proof) | Resource | | | (DPoP Proof) | Resource |
| | | Server | | | | Server |
| |<-(D)-- Protected Resource ---------------| | | |<-(D)-- Protected Resource ---------------| |
| | +---------------+ | | +---------------+
+--------+ +--------+
Figure 1: Basic DPoP Flow Figure 1: Basic DPoP Flow
The basic steps of an OAuth flow with DPoP (without the optional The basic steps of an OAuth flow with DPoP (without the optional
nonce) are shown in Figure 1: nonce) are shown in Figure 1.
* (A) In the Token Request, the client sends an authorization grant A. In the token request, the client sends an authorization grant
(e.g., an authorization code, refresh token, etc.) (e.g., an authorization code, refresh token, etc.) to the
to the authorization server in order to obtain an access token authorization server in order to obtain an access token (and
(and potentially a refresh token). The client attaches a DPoP potentially a refresh token). The client attaches a DPoP proof
proof to the request in an HTTP header. to the request in an HTTP header.
* (B) The authorization server binds (sender-constrains) the access
token to the public key claimed by the client in the DPoP proof; B. The authorization server binds (sender-constrains) the access
that is, the access token cannot be used without proving token to the public key claimed by the client in the DPoP proof;
possession of the respective private key. If a refresh token is that is, the access token cannot be used without proving
issued to a public client, it too is bound to the public key of possession of the respective private key. If a refresh token is
the DPoP proof. issued to a public client, it is also bound to the public key of
* (C) To use the access token, the client has to prove possession of the DPoP proof.
the private key by, again, adding a header to the request that
carries a DPoP proof for that request. The resource server needs C. To use the access token, the client has to prove possession of
to receive information about the public key to which the access the private key by, again, adding a header to the request that
token is bound. This information may be encoded directly into the carries a DPoP proof for that request. The resource server needs
access token (for JWT structured access tokens) or provided via to receive information about the public key to which the access
token introspection endpoint (not shown). The resource server token is bound. This information may be encoded directly into
verifies that the public key to which the access token is bound the access token (for JWT-structured access tokens) or provided
matches the public key of the DPoP proof. It also verifies that via token introspection endpoint (not shown). The resource
the access token hash in the DPoP proof matches the access token server verifies that the public key to which the access token is
presented in the request. bound matches the public key of the DPoP proof. It also verifies
* (D) The resource server refuses to serve the request if the that the access token hash in the DPoP proof matches the access
signature check fails or the data in the DPoP proof is wrong, token presented in the request.
e.g., the target URI does not match the URI claim in the DPoP
proof JWT. The access token itself, of course, must also be valid D. The resource server refuses to serve the request if the signature
in all other respects. check fails or if the data in the DPoP proof is wrong, e.g., the
target URI does not match the URI claim in the DPoP proof JWT.
The access token itself, of course, must also be valid in all
other respects.
The DPoP mechanism presented herein is not a client authentication The DPoP mechanism presented herein is not a client authentication
method. In fact, a primary use case of DPoP is for public clients method. In fact, a primary use case of DPoP is for public clients
(e.g., single page applications and applications on a user's device) (e.g., single-page applications and applications on a user's device)
that do not use client authentication. Nonetheless, DPoP is designed that do not use client authentication. Nonetheless, DPoP is designed
such that it is compatible with private_key_jwt and all other client to be compatible with private_key_jwt and all other client
authentication methods. authentication methods.
DPoP does not directly ensure message integrity but relies on the TLS DPoP does not directly ensure message integrity, but it relies on the
layer for that purpose. See Section 11 for details. TLS layer for that purpose. See Section 11 for details.
4. DPoP Proof JWTs 4. DPoP Proof JWTs
DPoP introduces the concept of a DPoP proof, which is a JWT created DPoP introduces the concept of a DPoP proof, which is a JWT created
by the client and sent with an HTTP request using the DPoP header by the client and sent with an HTTP request using the DPoP header
field. Each HTTP request requires a unique DPoP proof. field. Each HTTP request requires a unique DPoP proof.
A valid DPoP proof demonstrates to the server that the client holds A valid DPoP proof demonstrates to the server that the client holds
the private key that was used to sign the DPoP proof JWT. This the private key that was used to sign the DPoP proof JWT. This
enables authorization servers to bind issued tokens to the enables authorization servers to bind issued tokens to the
corresponding public key (as described in Section 5) and for resource corresponding public key (as described in Section 5) and enables
servers to verify the key-binding of tokens that it receives (see resource servers to verify the key-binding of tokens that it receives
Section 7.1), which prevents said tokens from being used by any (see Section 7.1), which prevents said tokens from being used by any
entity that does not have access to the private key. entity that does not have access to the private key.
The DPoP proof demonstrates possession of a key and, by itself, is The DPoP proof demonstrates possession of a key and, by itself, is
not an authentication or access control mechanism. When presented in not an authentication or access control mechanism. When presented in
conjunction with a key-bound access token as described in conjunction with a key-bound access token as described in
Section 7.1, the DPoP proof provides additional assurance about the Section 7.1, the DPoP proof provides additional assurance about the
legitimacy of the client to present the access token. However, a legitimacy of the client to present the access token. However, a
valid DPoP proof JWT is not sufficient alone to make access control valid DPoP proof JWT is not sufficient alone to make access control
decisions. decisions.
4.1. The DPoP HTTP Header 4.1. The DPoP HTTP Header
A DPoP proof is included in an HTTP request using the following A DPoP proof is included in an HTTP request using the following
request header field. request header field.
DPoP A JWT that adheres to the structure and syntax of Section 4.2. DPoP: A JWT that adheres to the structure and syntax of Section 4.2.
Figure 2 shows an example DPoP HTTP header field (with '\' line Figure 2 shows an example DPoP HTTP header field. The example uses
wrapping per RFC 8792). "\" line wrapping per [RFC8792].
DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrIjp7Imt0eSI6Ik\ DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrIjp7Imt0eSI6Ik\
VDIiwieCI6Imw4dEZyaHgtMzR0VjNoUklDUkRZOXpDa0RscEJoRjQyVVFVZldWQVdCR\ VDIiwieCI6Imw4dEZyaHgtMzR0VjNoUklDUkRZOXpDa0RscEJoRjQyVVFVZldWQVdCR\
nMiLCJ5IjoiOVZFNGpmX09rX282NHpiVFRsY3VOSmFqSG10NnY5VERWclUwQ2R2R1JE\ nMiLCJ5IjoiOVZFNGpmX09rX282NHpiVFRsY3VOSmFqSG10NnY5VERWclUwQ2R2R1JE\
QSIsImNydiI6IlAtMjU2In19.eyJqdGkiOiItQndDM0VTYzZhY2MybFRjIiwiaHRtIj\ QSIsImNydiI6IlAtMjU2In19.eyJqdGkiOiItQndDM0VTYzZhY2MybFRjIiwiaHRtIj\
oiUE9TVCIsImh0dSI6Imh0dHBzOi8vc2VydmVyLmV4YW1wbGUuY29tL3Rva2VuIiwia\ oiUE9TVCIsImh0dSI6Imh0dHBzOi8vc2VydmVyLmV4YW1wbGUuY29tL3Rva2VuIiwia\
WF0IjoxNTYyMjYyNjE2fQ.2-GxA6T8lP4vfrg8v-FdWP0A0zdrj8igiMLvqRMUvwnQg\ WF0IjoxNTYyMjYyNjE2fQ.2-GxA6T8lP4vfrg8v-FdWP0A0zdrj8igiMLvqRMUvwnQg\
4PtFLbdLXiOSsX0x7NVY-FNyJK70nfbV37xRZT3Lg 4PtFLbdLXiOSsX0x7NVY-FNyJK70nfbV37xRZT3Lg
Figure 2: Example DPoP header Figure 2: Example DPoP Header
Note that per [RFC9110] header field names are case-insensitive; so Note that per [RFC9110], header field names are case insensitive;
DPoP, DPOP, dpop, etc., are all valid and equivalent header field thus, DPoP, DPOP, dpop, etc., are all valid and equivalent header
names. Case is significant in the header field value, however. field names. However, case is significant in the header field value.
The DPoP HTTP header field value uses the token68 syntax defined in The DPoP HTTP header field value uses the token68 syntax defined in
Section 11.2 of [RFC9110] (repeated below in Figure 3 for ease of Section 11.2 of [RFC9110] and is repeated below in Figure 3 for ease
reference). of reference.
DPoP = token68 DPoP = token68
token68 = 1*( ALPHA / DIGIT / token68 = 1*( ALPHA / DIGIT /
"-" / "." / "_" / "~" / "+" / "/" ) *"=" "-" / "." / "_" / "~" / "+" / "/" ) *"="
Figure 3: DPoP header field ABNF Figure 3: DPoP Header Field ABNF
4.2. DPoP Proof JWT Syntax 4.2. DPoP Proof JWT Syntax
A DPoP proof is a JWT ([RFC7519]) that is signed (using JSON Web A DPoP proof is a JWT [RFC7519] that is signed (using JSON Web
Signature (JWS) [RFC7515]) with a private key chosen by the client Signature (JWS) [RFC7515]) with a private key chosen by the client
(see below). The JOSE header of a DPoP JWT MUST contain at least the (see below). The JOSE Header of a DPoP JWT MUST contain at least the
following parameters: following parameters:
* typ: with value dpop+jwt, which explicitly types the DPoP proof typ: A field with the value dpop+jwt, which explicitly types the
JWT as recommended in Section 3.11 of [RFC8725]. DPoP proof JWT as recommended in Section 3.11 of [RFC8725].
* alg: an identifier for a JWS asymmetric digital signature
algorithm from [IANA.JOSE.ALGS]. MUST NOT be none or an alg: An identifier for a JWS asymmetric digital signature algorithm
identifier for a symmetric algorithm (MAC). from [IANA.JOSE.ALGS]. It MUST NOT be none or an identifier for a
* jwk: representing the public key chosen by the client, in JSON Web symmetric algorithm (Message Authentication Code (MAC)).
Key (JWK) [RFC7517] format, as defined in Section 4.1.3 of
[RFC7515]. MUST NOT contain a private key. jwk: Represents the public key chosen by the client in JSON Web Key
(JWK) [RFC7517] format as defined in Section 4.1.3 of [RFC7515].
It MUST NOT contain a private key.
The payload of a DPoP proof MUST contain at least the following The payload of a DPoP proof MUST contain at least the following
claims: claims:
* jti: Unique identifier for the DPoP proof JWT. The value MUST be jti: Unique identifier for the DPoP proof JWT. The value MUST be
assigned such that there is a negligible probability that the same assigned such that there is a negligible probability that the same
value will be assigned to any other DPoP proof used in the same value will be assigned to any other DPoP proof used in the same
context during the time window of validity. Such uniqueness can context during the time window of validity. Such uniqueness can
be accomplished by encoding (base64url or any other suitable be accomplished by encoding (base64url or any other suitable
encoding) at least 96 bits of pseudorandom data or by using a encoding) at least 96 bits of pseudorandom data or by using a
version 4 UUID string according to [RFC4122]. The jti can be used version 4 Universally Unique Identifier (UUID) string according to
by the server for replay detection and prevention, see [RFC4122]. The jti can be used by the server for replay detection
Section 11.1. and prevention; see Section 11.1.
* htm: The value of the HTTP method (Section 9.1 of [RFC9110]) of
the request to which the JWT is attached. htm: The value of the HTTP method (Section 9.1 of [RFC9110]) of the
* htu: The HTTP target URI (Section 7.1 of [RFC9110]), without query request to which the JWT is attached.
and fragment parts, of the request to which the JWT is attached.
* iat: Creation timestamp of the JWT ([RFC7519], section 4.1.6]). htu: The HTTP target URI (Section 7.1 of [RFC9110]) of the request
to which the JWT is attached, without query and fragment parts.
iat: Creation timestamp of the JWT (Section 4.1.6 of [RFC7519]).
When the DPoP proof is used in conjunction with the presentation of When the DPoP proof is used in conjunction with the presentation of
an access token in protected resource access, see Section 7, the DPoP an access token in protected resource access (see Section 7), the
proof MUST also contain the following claim: DPoP proof MUST also contain the following claim:
* ath: hash of the access token. The value MUST be the result of a ath: Hash of the access token. The value MUST be the result of a
base64url encoding (as defined in Section 2 of [RFC7515]) the base64url encoding (as defined in Section 2 of [RFC7515]) the
SHA-256 [SHS] hash of the ASCII encoding of the associated access SHA-256 [SHS] hash of the ASCII encoding of the associated access
token's value. token's value.
When the authentication server or resource server provides a DPoP- When the authentication server or resource server provides a DPoP-
Nonce HTTP header in a response (see Section 8, Section 9), the DPoP Nonce HTTP header in a response (see Sections 8 and 9), the DPoP
proof MUST also contain the following claim: proof MUST also contain the following claim:
* nonce: A recent nonce provided via the DPoP-Nonce HTTP header. nonce: A recent nonce provided via the DPoP-Nonce HTTP header.
A DPoP proof MAY contain other JOSE header parameters or claims as A DPoP proof MAY contain other JOSE Header Parameters or claims as
defined by extension, profile, or deployment specific requirements. defined by extension, profile, or deployment-specific requirements.
Figure 4 is a conceptual example showing the decoded content of the Figure 4 is a conceptual example showing the decoded content of the
DPoP proof in Figure 2. The JSON of the JWT header and payload are DPoP proof in Figure 2. The JSON of the JWT header and payload are
shown, but the signature part is omitted. As usual, line breaks and shown, but the signature part is omitted. As usual, line breaks and
extra spaces are included for formatting and readability. extra spaces are included for formatting and readability.
{ {
"typ":"dpop+jwt", "typ":"dpop+jwt",
"alg":"ES256", "alg":"ES256",
"jwk": { "jwk": {
skipping to change at page 11, line 23 skipping to change at line 469
} }
} }
. .
{ {
"jti":"-BwC3ESc6acc2lTc", "jti":"-BwC3ESc6acc2lTc",
"htm":"POST", "htm":"POST",
"htu":"https://server.example.com/token", "htu":"https://server.example.com/token",
"iat":1562262616 "iat":1562262616
} }
Figure 4: Example JWT content of a DPoP proof Figure 4: Example JWT Content of a DPoP Proof
Of the HTTP request, only the HTTP method and URI are included in the Of the HTTP request, only the HTTP method and URI are included in the
DPoP JWT, and therefore only these two message parts are covered by DPoP JWT; therefore, only these two message parts are covered by the
the DPoP proof. The idea is sign just enough of the HTTP data to DPoP proof. The idea is to sign just enough of the HTTP data to
provide reasonable proof-of-possession with respect to the HTTP provide reasonable proof of possession with respect to the HTTP
request. This design approach of using only a minimal subset of the request. This design approach of using only a minimal subset of the
HTTP header data is to avoid the substantial difficulties inherent in HTTP header data is to avoid the substantial difficulties inherent in
attempting to normalize HTTP messages. Nonetheless, DPoP proofs can attempting to normalize HTTP messages. Nonetheless, DPoP proofs can
be extended to contain other information of the HTTP request (see be extended to contain other information of the HTTP request (see
also Section 11.7). also Section 11.7).
4.3. Checking DPoP Proofs 4.3. Checking DPoP Proofs
To validate a DPoP proof, the receiving server MUST ensure that To validate a DPoP proof, the receiving server MUST ensure the
following:
1. there is not more than one DPoP HTTP request header field, 1. There is not more than one DPoP HTTP request header field.
2. the DPoP HTTP request header field value is a single well-formed 2. The DPoP HTTP request header field value is a single and well-
JWT, formed JWT.
3. all required claims per Section 4.2 are contained in the JWT, 3. All required claims per Section 4.2 are contained in the JWT.
4. the typ JOSE header parameter has the value dpop+jwt, 4. The typ JOSE Header Parameter has the value dpop+jwt.
5. the alg JOSE header parameter indicates a registered asymmetric 5. The alg JOSE Header Parameter indicates a registered asymmetric
digital signature algorithm [IANA.JOSE.ALGS], is not none, is digital signature algorithm [IANA.JOSE.ALGS], is not none, is
supported by the application, and is acceptable per local supported by the application, and is acceptable per local
policy, policy.
6. the JWT signature verifies with the public key contained in the 6. The JWT signature verifies with the public key contained in the
jwk JOSE header parameter, jwk JOSE Header Parameter.
7. the jwk JOSE header parameter does not contain a private key, 7. The jwk JOSE Header Parameter does not contain a private key.
8. the htm claim matches the HTTP method of the current request, 8. The htm claim matches the HTTP method of the current request.
9. the htu claim matches the HTTP URI value for the HTTP request in 9. The htu claim matches the HTTP URI value for the HTTP request in
which the JWT was received, ignoring any query and fragment which the JWT was received, ignoring any query and fragment
parts, parts.
10. if the server provided a nonce value to the client, the nonce 10. If the server provided a nonce value to the client, the nonce
claim matches the server-provided nonce value, claim matches the server-provided nonce value.
11. the creation time of the JWT, as determined by either the iat 11. The creation time of the JWT, as determined by either the iat
claim or a server managed timestamp via the nonce claim, is claim or a server managed timestamp via the nonce claim, is
within an acceptable window (see Section 11.1), within an acceptable window (see Section 11.1).
12. if presented to a protected resource in conjunction with an 12. If presented to a protected resource in conjunction with an
access token, access token,
* ensure that the value of the ath claim equals the hash of * ensure that the value of the ath claim equals the hash of
that access token, that access token, and
* confirm that the public key to which the access token is * confirm that the public key to which the access token is
bound matches the public key from the DPoP proof. bound matches the public key from the DPoP proof.
To reduce the likelihood of false negatives, servers SHOULD employ To reduce the likelihood of false negatives, servers SHOULD employ
Syntax-Based Normalization (Section 6.2.2 of [RFC3986]) and Scheme- syntax-based normalization (Section 6.2.2 of [RFC3986]) and scheme-
Based Normalization (Section 6.2.3 of [RFC3986]) before comparing the based normalization (Section 6.2.3 of [RFC3986]) before comparing the
htu claim. htu claim.
These checks may be performed in any order. These checks may be performed in any order.
5. DPoP Access Token Request 5. DPoP Access Token Request
To request an access token that is bound to a public key using DPoP, To request an access token that is bound to a public key using DPoP,
the client MUST provide a valid DPoP proof JWT in a DPoP header when the client MUST provide a valid DPoP proof JWT in a DPoP header when
making an access token request to the authorization server's token making an access token request to the authorization server's token
endpoint. This is applicable for all access token requests endpoint. This is applicable for all access token requests
regardless of grant type (including, for example, the common regardless of grant type (e.g., the common authorization_code and
authorization_code and refresh_token grant types but also extension refresh_token grant types and extension grants such as the JWT
grants such as the JWT authorization grant [RFC7523]). The HTTP authorization grant [RFC7523]). The HTTP request shown in Figure 5
request shown in Figure 5 illustrates such an access token request illustrates such an access token request using an authorization code
using an authorization code grant with a DPoP proof JWT in the DPoP grant with a DPoP proof JWT in the DPoP header. Figure 5 uses "\"
header (with '\' line wrapping per RFC 8792). line wrapping per [RFC8792].
POST /token HTTP/1.1 POST /token HTTP/1.1
Host: server.example.com Host: server.example.com
Content-Type: application/x-www-form-urlencoded Content-Type: application/x-www-form-urlencoded
DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrIjp7Imt0eSI6Ik\ DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrIjp7Imt0eSI6Ik\
VDIiwieCI6Imw4dEZyaHgtMzR0VjNoUklDUkRZOXpDa0RscEJoRjQyVVFVZldWQVdCR\ VDIiwieCI6Imw4dEZyaHgtMzR0VjNoUklDUkRZOXpDa0RscEJoRjQyVVFVZldWQVdCR\
nMiLCJ5IjoiOVZFNGpmX09rX282NHpiVFRsY3VOSmFqSG10NnY5VERWclUwQ2R2R1JE\ nMiLCJ5IjoiOVZFNGpmX09rX282NHpiVFRsY3VOSmFqSG10NnY5VERWclUwQ2R2R1JE\
QSIsImNydiI6IlAtMjU2In19.eyJqdGkiOiItQndDM0VTYzZhY2MybFRjIiwiaHRtIj\ QSIsImNydiI6IlAtMjU2In19.eyJqdGkiOiItQndDM0VTYzZhY2MybFRjIiwiaHRtIj\
oiUE9TVCIsImh0dSI6Imh0dHBzOi8vc2VydmVyLmV4YW1wbGUuY29tL3Rva2VuIiwia\ oiUE9TVCIsImh0dSI6Imh0dHBzOi8vc2VydmVyLmV4YW1wbGUuY29tL3Rva2VuIiwia\
WF0IjoxNTYyMjYyNjE2fQ.2-GxA6T8lP4vfrg8v-FdWP0A0zdrj8igiMLvqRMUvwnQg\ WF0IjoxNTYyMjYyNjE2fQ.2-GxA6T8lP4vfrg8v-FdWP0A0zdrj8igiMLvqRMUvwnQg\
4PtFLbdLXiOSsX0x7NVY-FNyJK70nfbV37xRZT3Lg 4PtFLbdLXiOSsX0x7NVY-FNyJK70nfbV37xRZT3Lg
grant_type=authorization_code\ grant_type=authorization_code\
&client_id=s6BhdRkqt\ &client_id=s6BhdRkqt\
&code=SplxlOBeZQQYbYS6WxSbIA &code=SplxlOBeZQQYbYS6WxSbIA
&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb\ &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb\
&code_verifier=bEaL42izcC-o-xBk0K2vuJ6U-y1p9r_wW2dFWIWgjz- &code_verifier=bEaL42izcC-o-xBk0K2vuJ6U-y1p9r_wW2dFWIWgjz-
Figure 5: Token Request for a DPoP sender-constrained token using an Figure 5: Token Request for a DPoP Sender-Constrained Token Using an
authorization code Authorization Code
The DPoP HTTP header field MUST contain a valid DPoP proof JWT. If The DPoP HTTP header field MUST contain a valid DPoP proof JWT. If
the DPoP proof is invalid, the authorization server issues an error the DPoP proof is invalid, the authorization server issues an error
response per Section 5.2 of [RFC6749] with invalid_dpop_proof as the response per Section 5.2 of [RFC6749] with invalid_dpop_proof as the
value of the error parameter. value of the error parameter.
To sender-constrain the access token, after checking the validity of To sender-constrain the access token after checking the validity of
the DPoP proof, the authorization server associates the issued access the DPoP proof, the authorization server associates the issued access
token with the public key from the DPoP proof, which can be token with the public key from the DPoP proof, which can be
accomplished as described in Section 6. A token_type of DPoP MUST be accomplished as described in Section 6. A token_type of DPoP MUST be
included in the access token response to signal to the client that included in the access token response to signal to the client that
the access token was bound to its DPoP key and can be used as the access token was bound to its DPoP key and can be used as
described in Section 7.1. The example response shown in Figure 6 described in Section 7.1. The example response shown in Figure 6
illustrates such a response. illustrates such a response.
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Type: application/json Content-Type: application/json
skipping to change at page 14, line 5 skipping to change at line 581
{ {
"access_token": "Kz~8mXK1EalYznwH-LC-1fBAo.4Ljp~zsPE_NeO.gxU", "access_token": "Kz~8mXK1EalYznwH-LC-1fBAo.4Ljp~zsPE_NeO.gxU",
"token_type": "DPoP", "token_type": "DPoP",
"expires_in": 2677, "expires_in": 2677,
"refresh_token": "Q..Zkm29lexi8VnWg2zPW1x-tgGad0Ibc3s3EwM_Ni4-g" "refresh_token": "Q..Zkm29lexi8VnWg2zPW1x-tgGad0Ibc3s3EwM_Ni4-g"
} }
Figure 6: Access Token Response Figure 6: Access Token Response
The example response in Figure 6 includes a refresh token which the The example response in Figure 6 includes a refresh token that the
client can use to obtain a new access token when the previous one client can use to obtain a new access token when the previous one
expires. Refreshing an access token is a token request using the expires. Refreshing an access token is a token request using the
refresh_token grant type made to the authorization server's token refresh_token grant type made to the authorization server's token
endpoint. As with all access token requests, the client makes it a endpoint. As with all access token requests, the client makes it a
DPoP request by including a DPoP proof, as shown in the Figure 7 DPoP request by including a DPoP proof, as shown in Figure 7.
example (with '\' line wrapping per RFC 8792). Figure 7 uses "\" line wrapping per [RFC8792].
POST /token HTTP/1.1 POST /token HTTP/1.1
Host: server.example.com Host: server.example.com
Content-Type: application/x-www-form-urlencoded Content-Type: application/x-www-form-urlencoded
DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrIjp7Imt0eSI6Ik\ DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrIjp7Imt0eSI6Ik\
VDIiwieCI6Imw4dEZyaHgtMzR0VjNoUklDUkRZOXpDa0RscEJoRjQyVVFVZldWQVdCR\ VDIiwieCI6Imw4dEZyaHgtMzR0VjNoUklDUkRZOXpDa0RscEJoRjQyVVFVZldWQVdCR\
nMiLCJ5IjoiOVZFNGpmX09rX282NHpiVFRsY3VOSmFqSG10NnY5VERWclUwQ2R2R1JE\ nMiLCJ5IjoiOVZFNGpmX09rX282NHpiVFRsY3VOSmFqSG10NnY5VERWclUwQ2R2R1JE\
QSIsImNydiI6IlAtMjU2In19.eyJqdGkiOiItQndDM0VTYzZhY2MybFRjIiwiaHRtIj\ QSIsImNydiI6IlAtMjU2In19.eyJqdGkiOiItQndDM0VTYzZhY2MybFRjIiwiaHRtIj\
oiUE9TVCIsImh0dSI6Imh0dHBzOi8vc2VydmVyLmV4YW1wbGUuY29tL3Rva2VuIiwia\ oiUE9TVCIsImh0dSI6Imh0dHBzOi8vc2VydmVyLmV4YW1wbGUuY29tL3Rva2VuIiwia\
WF0IjoxNTYyMjY1Mjk2fQ.pAqut2IRDm_De6PR93SYmGBPXpwrAk90e8cP2hjiaG5Qs\ WF0IjoxNTYyMjY1Mjk2fQ.pAqut2IRDm_De6PR93SYmGBPXpwrAk90e8cP2hjiaG5Qs\
GSuKDYW7_X620BxqhvYC8ynrrvZLTk41mSRroapUA GSuKDYW7_X620BxqhvYC8ynrrvZLTk41mSRroapUA
grant_type=refresh_token\ grant_type=refresh_token\
&client_id=s6BhdRkqt\ &client_id=s6BhdRkqt\
&refresh_token=Q..Zkm29lexi8VnWg2zPW1x-tgGad0Ibc3s3EwM_Ni4-g &refresh_token=Q..Zkm29lexi8VnWg2zPW1x-tgGad0Ibc3s3EwM_Ni4-g
Figure 7: Token Request for a DPoP-bound Token using a Refresh Token Figure 7: Token Request for a DPoP-Bound Token Using a Refresh Token
When an authorization server supporting DPoP issues a refresh token When an authorization server supporting DPoP issues a refresh token
to a public client that presents a valid DPoP proof at the token to a public client that presents a valid DPoP proof at the token
endpoint, the refresh token MUST be bound to the respective public endpoint, the refresh token MUST be bound to the respective public
key. The binding MUST be validated when the refresh token is later key. The binding MUST be validated when the refresh token is later
presented to get new access tokens. As a result, such a client MUST presented to get new access tokens. As a result, such a client MUST
present a DPoP proof for the same key that was used to obtain the present a DPoP proof for the same key that was used to obtain the
refresh token each time that refresh token is used to obtain a new refresh token each time that refresh token is used to obtain a new
access token. The implementation details of the binding of the access token. The implementation details of the binding of the
refresh token are at the discretion of the authorization server. refresh token are at the discretion of the authorization server.
Since the authorization server both produces and validates its Since the authorization server both produces and validates its
refresh tokens, there is no interoperability consideration in the refresh tokens, there is no interoperability consideration in the
specific details of the binding. specific details of the binding.
An authorization server MAY elect to issue access tokens which are An authorization server MAY elect to issue access tokens that are not
not DPoP bound, which is signaled to the client with a value of DPoP bound, which is signaled to the client with a value of Bearer in
Bearer in the token_type parameter of the access token response per the token_type parameter of the access token response per [RFC6750].
[RFC6750]. For a public client that is also issued a refresh token, For a public client that is also issued a refresh token, this has the
this has the effect of DPoP-binding the refresh token alone, which effect of DPoP-binding the refresh token alone, which can improve the
can improve the security posture even when protected resources are security posture even when protected resources are not updated to
not updated to support DPoP. support DPoP.
If the access token response contains a different token_type value If the access token response contains a different token_type value
than DPoP, the access token protection provided by DPoP is not given. than DPoP, the access token protection provided by DPoP is not given.
The client MUST discard the response in this case, if this protection The client MUST discard the response in this case if this protection
is deemed important for the security of the application; otherwise, is deemed important for the security of the application; otherwise,
it may continue as in a regular OAuth interaction. the client may continue as in a regular OAuth interaction.
Refresh tokens issued to confidential clients (those having Refresh tokens issued to confidential clients (those having
established authentication credentials with the authorization server) established authentication credentials with the authorization server)
are not bound to the DPoP proof public key because they are already are not bound to the DPoP proof public key because they are already
sender-constrained with a different existing mechanism. The OAuth sender-constrained with a different existing mechanism. The OAuth
2.0 Authorization Framework [RFC6749] already requires that an 2.0 Authorization Framework [RFC6749] already requires that an
authorization server bind refresh tokens to the client to which they authorization server bind refresh tokens to the client to which they
were issued and that confidential clients authenticate to the were issued and that confidential clients authenticate to the
authorization server when presenting a refresh token. As a result, authorization server when presenting a refresh token. As a result,
such refresh tokens are sender-constrained by way of the client such refresh tokens are sender-constrained by way of the client
skipping to change at page 15, line 32 skipping to change at line 654
allows credential rotation for the client without invalidating allows credential rotation for the client without invalidating
refresh tokens) than binding directly to a particular public key. refresh tokens) than binding directly to a particular public key.
5.1. Authorization Server Metadata 5.1. Authorization Server Metadata
This document introduces the following authorization server metadata This document introduces the following authorization server metadata
[RFC8414] parameter to signal support for DPoP in general and the [RFC8414] parameter to signal support for DPoP in general and the
specific JWS alg values the authorization server supports for DPoP specific JWS alg values the authorization server supports for DPoP
proof JWTs. proof JWTs.
dpop_signing_alg_values_supported A JSON array containing a list of dpop_signing_alg_values_supported: A JSON array containing a list of
the JWS alg values (from the [IANA.JOSE.ALGS] registry) supported the JWS alg values (from the [IANA.JOSE.ALGS] registry) supported
by the authorization server for DPoP proof JWTs. by the authorization server for DPoP proof JWTs.
5.2. Client Registration Metadata 5.2. Client Registration Metadata
The Dynamic Client Registration Protocol [RFC7591] defines an API for The Dynamic Client Registration Protocol [RFC7591] defines an API for
dynamically registering OAuth 2.0 client metadata with authorization dynamically registering OAuth 2.0 client metadata with authorization
servers. The metadata defined by [RFC7591], and registered servers. The metadata defined by [RFC7591], and registered
extensions to it, also imply a general data model for clients that is extensions to it, also imply a general data model for clients that is
useful for authorization server implementations even when the Dynamic useful for authorization server implementations even when the Dynamic
Client Registration Protocol isn't in play. Such implementations Client Registration Protocol isn't in play. Such implementations
will typically have some sort of user interface available for will typically have some sort of user interface available for
managing client configuration. managing client configuration.
This document introduces the following client registration metadata This document introduces the following client registration metadata
[RFC7591] parameter to indicate that the client always uses DPoP when [RFC7591] parameter to indicate that the client always uses DPoP when
requesting tokens from the authorization server. requesting tokens from the authorization server.
dpop_bound_access_tokens Boolean value specifying whether the client dpop_bound_access_tokens: A boolean value specifying whether the
always uses DPoP for token requests. If omitted, the default client always uses DPoP for token requests. If omitted, the
value is false. default value is false.
If true, the authorization server MUST reject token requests from If the value is true, the authorization server MUST reject token
this client that do not contain the DPoP header. requests from the client that do not contain the DPoP header.
6. Public Key Confirmation 6. Public Key Confirmation
Resource servers MUST be able to reliably identify whether an access Resource servers MUST be able to reliably identify whether an access
token is DPoP-bound and ascertain sufficient information to verify token is DPoP-bound and ascertain sufficient information to verify
the binding to the public key of the DPoP proof (see Section 7.1). the binding to the public key of the DPoP proof (see Section 7.1).
Such a binding is accomplished by associating the public key with the Such a binding is accomplished by associating the public key with the
token in a way that can be accessed by the protected resource, such token in a way that can be accessed by the protected resource, such
as embedding the JWK hash in the issued access token directly, using as embedding the JWK hash in the issued access token directly, using
the syntax described in Section 6.1, or through token introspection the syntax described in Section 6.1, or through token introspection
as described in Section 6.2. Other methods of associating a public as described in Section 6.2. Other methods of associating a public
key with an access token are possible, per agreement by the key with an access token are possible per an agreement by the
authorization server and the protected resource, but are beyond the authorization server and the protected resource; however, they are
scope of this specification. beyond the scope of this specification.
Resource servers supporting DPoP MUST ensure that the public key from Resource servers supporting DPoP MUST ensure that the public key from
the DPoP proof matches the one bound to the access token. the DPoP proof matches the one bound to the access token.
6.1. JWK Thumbprint Confirmation Method 6.1. JWK Thumbprint Confirmation Method
When access tokens are represented as JWTs [RFC7519], the public key When access tokens are represented as JWTs [RFC7519], the public key
information is represented using the jkt confirmation method member information is represented using the jkt confirmation method member
defined herein. To convey the hash of a public key in a JWT, this defined herein. To convey the hash of a public key in a JWT, this
specification introduces the following JWT Confirmation Method specification introduces the following JWT Confirmation Method
[RFC7800] member for use under the cnf claim. [RFC7800] member for use under the cnf claim.
jkt JWK SHA-256 Thumbprint Confirmation Method. The value of the jkt: JWK SHA-256 Thumbprint confirmation method. The value of the
jkt member MUST be the base64url encoding (as defined in jkt member MUST be the base64url encoding (as defined in
[RFC7515]) of the JWK SHA-256 Thumbprint (according to [RFC7638]) [RFC7515]) of the JWK SHA-256 Thumbprint (according to [RFC7638])
of the DPoP public key (in JWK format) to which the access token of the DPoP public key (in JWK format) to which the access token
is bound. is bound.
The following example JWT in Figure 8 with decoded JWT payload shown The following example JWT in Figure 8 with a decoded JWT payload
in Figure 9 contains a cnf claim with the jkt JWK Thumbprint shown in Figure 9 contains a cnf claim with the jkt JWK Thumbprint
confirmation method member. The jkt value in these examples is the confirmation method member. The jkt value in these examples is the
hash of the public key from the DPoP proofs in the examples in hash of the public key from the DPoP proofs in the examples shown in
Section 5. (The example uses '\' line wrapping per RFC 8792.) Section 5. The example uses "\" line wrapping per [RFC8792].
eyJhbGciOiJFUzI1NiIsImtpZCI6IkJlQUxrYiJ9.eyJzdWIiOiJzb21lb25lQGV4YW1\ eyJhbGciOiJFUzI1NiIsImtpZCI6IkJlQUxrYiJ9.eyJzdWIiOiJzb21lb25lQGV4YW1\
wbGUuY29tIiwiaXNzIjoiaHR0cHM6Ly9zZXJ2ZXIuZXhhbXBsZS5jb20iLCJuYmYiOjE\ wbGUuY29tIiwiaXNzIjoiaHR0cHM6Ly9zZXJ2ZXIuZXhhbXBsZS5jb20iLCJuYmYiOjE\
1NjIyNjI2MTEsImV4cCI6MTU2MjI2NjIxNiwiY25mIjp7ImprdCI6IjBaY09DT1JaTll\ 1NjIyNjI2MTEsImV4cCI6MTU2MjI2NjIxNiwiY25mIjp7ImprdCI6IjBaY09DT1JaTll\
5LURXcHFxMzBqWnlKR0hUTjBkMkhnbEJWM3VpZ3VBNEkifX0.3Tyo8VTcn6u_PboUmAO\ 5LURXcHFxMzBqWnlKR0hUTjBkMkhnbEJWM3VpZ3VBNEkifX0.3Tyo8VTcn6u_PboUmAO\
YUY1kfAavomW_YwYMkmRNizLJoQzWy2fCo79Zi5yObpIzjWb5xW4OGld7ESZrh0fsrA YUY1kfAavomW_YwYMkmRNizLJoQzWy2fCo79Zi5yObpIzjWb5xW4OGld7ESZrh0fsrA
Figure 8: JWT containing a JWK SHA-256 Thumbprint Confirmation
Figure 8: JWT Containing a JWK SHA-256 Thumbprint Confirmation
{ {
"sub":"someone@example.com", "sub":"someone@example.com",
"iss":"https://server.example.com", "iss":"https://server.example.com",
"nbf":1562262611, "nbf":1562262611,
"exp":1562266216, "exp":1562266216,
"cnf": "cnf":
{ {
"jkt":"0ZcOCORZNYy-DWpqq30jZyJGHTN0d2HglBV3uiguA4I" "jkt":"0ZcOCORZNYy-DWpqq30jZyJGHTN0d2HglBV3uiguA4I"
} }
} }
Figure 9: JWT Claims Set with a JWK SHA-256 Thumbprint Confirmation Figure 9: JWT Claims Set with a JWK SHA-256 Thumbprint Confirmation
6.2. JWK Thumbprint Confirmation Method in Token Introspection 6.2. JWK Thumbprint Confirmation Method in Token Introspection
OAuth 2.0 Token Introspection [RFC7662] defines a method for a "OAuth 2.0 Token Introspection" [RFC7662] defines a method for a
protected resource to query an authorization server about the active protected resource to query an authorization server about the active
state of an access token as well as to determine metainformation state of an access token. The protected resource also determines
about the token. metainformation about the token.
For a DPoP-bound access token, the hash of the public key to which For a DPoP-bound access token, the hash of the public key to which
the token is bound is conveyed to the protected resource as the token is bound is conveyed to the protected resource as
metainformation in a token introspection response. The hash is metainformation in a token introspection response. The hash is
conveyed using the same cnf content with jkt member structure as the conveyed using the same cnf content with jkt member structure as the
JWK Thumbprint confirmation method, described in Section 6.1, as a JWK Thumbprint confirmation method, described in Section 6.1, as a
top-level member of the introspection response JSON. Note that the top-level member of the introspection response JSON. Note that the
resource server does not send a DPoP proof with the introspection resource server does not send a DPoP proof with the introspection
request and the authorization server does not validate an access request, and the authorization server does not validate an access
token's DPoP binding at the introspection endpoint. Rather the token's DPoP binding at the introspection endpoint. Rather, the
resource server uses the data of the introspection response to resource server uses the data of the introspection response to
validate the access token binding itself locally. validate the access token binding itself locally.
If the token_type member is included in the introspection response, If the token_type member is included in the introspection response,
it MUST contain the value DPoP. it MUST contain the value DPoP.
The example introspection request in Figure 10 and corresponding The example introspection request in Figure 10 and corresponding
response in Figure 11 illustrate an introspection exchange for the response in Figure 11 illustrate an introspection exchange for the
example DPoP-bound access token that was issued in Figure 6. example DPoP-bound access token that was issued in Figure 6.
skipping to change at page 18, line 27 skipping to change at line 794
{ {
"jkt": "0ZcOCORZNYy-DWpqq30jZyJGHTN0d2HglBV3uiguA4I" "jkt": "0ZcOCORZNYy-DWpqq30jZyJGHTN0d2HglBV3uiguA4I"
} }
} }
Figure 11: Example Introspection Response for a DPoP-Bound Access Figure 11: Example Introspection Response for a DPoP-Bound Access
Token Token
7. Protected Resource Access 7. Protected Resource Access
Requests to DPoP protected resources MUST include both a DPoP proof Requests to DPoP-protected resources MUST include both a DPoP proof
as per Section 4 and the access token as described in Section 7.1. as per Section 4 and the access token as described in Section 7.1.
The DPoP proof MUST include the ath claim with a valid hash of the The DPoP proof MUST include the ath claim with a valid hash of the
associated access token. associated access token.
Binding the token value to the proof in this way prevents a proof to Binding the token value to the proof in this way prevents a proof to
be used with multiple different access token values across different be used with multiple different access token values across different
requests. For example, if a client holds tokens bound to two requests. For example, if a client holds tokens bound to two
different resource owners, AT1 and AT2, and uses the same key when different resource owners, AT1 and AT2, and uses the same key when
talking to the AS, it's possible that these tokens could be swapped. talking to the authorization server, it's possible that these tokens
Without the ath field to bind it, a captured signature applied to AT1 could be swapped. Without the ath field to bind it, a captured
could be replayed with AT2 instead, changing the rights and access of signature applied to AT1 could be replayed with AT2 instead, changing
the intended request. This same substitution prevention remains for the rights and access of the intended request. This same
rotated access tokens within the same combination of client and substitution prevention remains for rotated access tokens within the
resource owner -- a rotated token value would require the calculation same combination of client and resource owner -- a rotated token
of a new proof. This binding additionally ensures that a proof value would require the calculation of a new proof. This binding
intended for use with the access token is not usable without an additionally ensures that a proof intended for use with the access
access token, or vice-versa. token is not usable without an access token, or vice-versa.
The resource server is required to calculate the hash of the token The resource server is required to calculate the hash of the token
value presented and verify that it is the same as the hash value in value presented and verify that it is the same as the hash value in
the ath field as described in Section 4.3. Since the ath field value the ath field as described in Section 4.3. Since the ath field value
is covered by the DPoP proof's signature, its inclusion binds the is covered by the DPoP proof's signature, its inclusion binds the
access token value to the holder of the key used to generate the access token value to the holder of the key used to generate the
signature. signature.
Note that the ath field alone does not prevent replay of the DPoP Note that the ath field alone does not prevent replay of the DPoP
proof or provide binding to the request in which the proof is proof or provide binding to the request in which the proof is
presented, and it is still important to check the time window of the presented, and it is still important to check the time window of the
proof as well as the included message parameters such as htm and htu. proof as well as the included message parameters, such as htm and
htu.
7.1. The DPoP Authentication Scheme 7.1. The DPoP Authentication Scheme
A DPoP-bound access token is sent using the Authorization request A DPoP-bound access token is sent using the Authorization request
header field per Section 11.6.2 of [RFC9110] using an authentication header field per Section 11.6.2 of [RFC9110] with an authentication
scheme of DPoP. The syntax of the Authorization header field for the scheme of DPoP. The syntax of the Authorization header field for the
DPoP scheme uses the token68 syntax defined in Section 11.2 of DPoP scheme uses the token68 syntax defined in Section 11.2 of
[RFC9110] (repeated below for ease of reference) for credentials. [RFC9110] for credentials and is repeated below for ease of
The ABNF notation syntax for DPoP authentication scheme credentials reference. The ABNF notation syntax for DPoP authentication scheme
is as follows: credentials is as follows:
token68 = 1*( ALPHA / DIGIT / token68 = 1*( ALPHA / DIGIT /
"-" / "." / "_" / "~" / "+" / "/" ) *"=" "-" / "." / "_" / "~" / "+" / "/" ) *"="
credentials = "DPoP" 1*SP token68 credentials = "DPoP" 1*SP token68
Figure 12: DPoP Authentication Scheme ABNF Figure 12: DPoP Authentication Scheme ABNF
For such an access token, a resource server MUST check that a DPoP For such an access token, a resource server MUST check that a DPoP
proof was also received in the DPoP header field of the HTTP request, proof was also received in the DPoP header field of the HTTP request,
check the DPoP proof according to the rules in Section 4.3, and check check the DPoP proof according to the rules in Section 4.3, and check
that the public key of the DPoP proof matches the public key to which that the public key of the DPoP proof matches the public key to which
the access token is bound per Section 6. the access token is bound per Section 6.
The resource server MUST NOT grant access to the resource unless all The resource server MUST NOT grant access to the resource unless all
checks are successful. checks are successful.
Figure 13 shows an example request to a protected resource with a Figure 13 shows an example request to a protected resource with a
DPoP-bound access token in the Authorization header and the DPoP DPoP-bound access token in the Authorization header and the DPoP
proof in the DPoP header (with '\' line wrapping per RFC 8792). proof in the DPoP header. The example uses "\" line wrapping per
Following that is Figure 14, which shows the decoded content of that [RFC8792]. Figure 14 shows the decoded content of that DPoP proof.
DPoP proof. The JSON of the JWT header and payload are shown but the The JSON of the JWT header and payload are shown, but the signature
signature part is omitted. As usual, line breaks and indentation are part is omitted. As usual, line breaks and indentation are included
included for formatting and readability. for formatting and readability.
GET /protectedresource HTTP/1.1 GET /protectedresource HTTP/1.1
Host: resource.example.org Host: resource.example.org
Authorization: DPoP Kz~8mXK1EalYznwH-LC-1fBAo.4Ljp~zsPE_NeO.gxU Authorization: DPoP Kz~8mXK1EalYznwH-LC-1fBAo.4Ljp~zsPE_NeO.gxU
DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrIjp7Imt0eSI6Ik\ DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IkVTMjU2IiwiandrIjp7Imt0eSI6Ik\
VDIiwieCI6Imw4dEZyaHgtMzR0VjNoUklDUkRZOXpDa0RscEJoRjQyVVFVZldWQVdCR\ VDIiwieCI6Imw4dEZyaHgtMzR0VjNoUklDUkRZOXpDa0RscEJoRjQyVVFVZldWQVdCR\
nMiLCJ5IjoiOVZFNGpmX09rX282NHpiVFRsY3VOSmFqSG10NnY5VERWclUwQ2R2R1JE\ nMiLCJ5IjoiOVZFNGpmX09rX282NHpiVFRsY3VOSmFqSG10NnY5VERWclUwQ2R2R1JE\
QSIsImNydiI6IlAtMjU2In19.eyJqdGkiOiJlMWozVl9iS2ljOC1MQUVCIiwiaHRtIj\ QSIsImNydiI6IlAtMjU2In19.eyJqdGkiOiJlMWozVl9iS2ljOC1MQUVCIiwiaHRtIj\
oiR0VUIiwiaHR1IjoiaHR0cHM6Ly9yZXNvdXJjZS5leGFtcGxlLm9yZy9wcm90ZWN0Z\ oiR0VUIiwiaHR1IjoiaHR0cHM6Ly9yZXNvdXJjZS5leGFtcGxlLm9yZy9wcm90ZWN0Z\
WRyZXNvdXJjZSIsImlhdCI6MTU2MjI2MjYxOCwiYXRoIjoiZlVIeU8ycjJaM0RaNTNF\ WRyZXNvdXJjZSIsImlhdCI6MTU2MjI2MjYxOCwiYXRoIjoiZlVIeU8ycjJaM0RaNTNF\
c05yV0JiMHhXWG9hTnk1OUlpS0NBcWtzbVFFbyJ9.2oW9RP35yRqzhrtNP86L-Ey71E\ c05yV0JiMHhXWG9hTnk1OUlpS0NBcWtzbVFFbyJ9.2oW9RP35yRqzhrtNP86L-Ey71E\
OptxRimPPToA1plemAgR6pxHF8y6-yqyVnmcw6Fy1dqd-jfxSYoMxhAJpLjA OptxRimPPToA1plemAgR6pxHF8y6-yqyVnmcw6Fy1dqd-jfxSYoMxhAJpLjA
Figure 13: DPoP Protected Resource Request Figure 13: DPoP-Protected Resource Request
{ {
"typ":"dpop+jwt", "typ":"dpop+jwt",
"alg":"ES256", "alg":"ES256",
"jwk": { "jwk": {
"kty":"EC", "kty":"EC",
"x":"l8tFrhx-34tV3hRICRDY9zCkDlpBhF42UQUfWVAWBFs", "x":"l8tFrhx-34tV3hRICRDY9zCkDlpBhF42UQUfWVAWBFs",
"y":"9VE4jf_Ok_o64zbTTlcuNJajHmt6v9TDVrU0CdvGRDA", "y":"9VE4jf_Ok_o64zbTTlcuNJajHmt6v9TDVrU0CdvGRDA",
"crv":"P-256" "crv":"P-256"
} }
skipping to change at page 20, line 41 skipping to change at line 896
"jti":"e1j3V_bKic8-LAEB", "jti":"e1j3V_bKic8-LAEB",
"htm":"GET", "htm":"GET",
"htu":"https://resource.example.org/protectedresource", "htu":"https://resource.example.org/protectedresource",
"iat":1562262618, "iat":1562262618,
"ath":"fUHyO2r2Z3DZ53EsNrWBb0xWXoaNy59IiKCAqksmQEo" "ath":"fUHyO2r2Z3DZ53EsNrWBb0xWXoaNy59IiKCAqksmQEo"
} }
Figure 14: Decoded Content of the DPoP Proof JWT in Figure 13 Figure 14: Decoded Content of the DPoP Proof JWT in Figure 13
Upon receipt of a request to a protected resource within the Upon receipt of a request to a protected resource within the
protection space requiring DPoP authentication, if the request does protection space requiring DPoP authentication, the server can
not include valid credentials or does not contain an access token respond with a challenge to the client to provide DPoP authentication
sufficient for access, the server can respond with a challenge to the information if the request does not include valid credentials or does
client to provide DPoP authentication information. Such a challenge not contain an access token sufficient for access. Such a challenge
is made using the 401 (Unauthorized) response status code ([RFC9110], is made using the 401 (Unauthorized) response status code ([RFC9110],
Section 15.5.2) and the WWW-Authenticate header field ([RFC9110], Section 15.5.2) and the WWW-Authenticate header field ([RFC9110],
Section 11.6.1). The server MAY include the WWW-Authenticate header Section 11.6.1). The server MAY include the WWW-Authenticate header
in response to other conditions as well. in response to other conditions as well.
In such challenges: In such challenges:
* The scheme name is DPoP. * The scheme name is DPoP.
* The authentication parameter realm MAY be included to indicate the * The authentication parameter realm MAY be included to indicate the
scope of protection in the manner described in [RFC9110], scope of protection in the manner described in [RFC9110],
Section 11.5. Section 11.5.
* A scope authentication parameter MAY be included as defined in * A scope authentication parameter MAY be included as defined in
[RFC6750], Section 3. [RFC6750], Section 3.
* An error parameter ([RFC6750], Section 3) SHOULD be included to * An error parameter ([RFC6750], Section 3) SHOULD be included to
indicate the reason why the request was declined, if the request indicate the reason why the request was declined, if the request
included an access token but failed authentication. The error included an access token but failed authentication. The error
parameter values described in Section 3.1 of [RFC6750] are parameter values described in [RFC6750], Section 3.1 are suitable,
suitable as are any appropriate values defined by extension. The as are any appropriate values defined by extension. The value
value use_dpop_nonce can be used as described in Section 9 to use_dpop_nonce can be used as described in Section 9 to signal
signal that a nonce is needed in the DPoP proof of subsequent that a nonce is needed in the DPoP proof of a subsequent
request(s). And invalid_dpop_proof is used to indicate that the request(s). Additionally, invalid_dpop_proof is used to indicate
DPoP proof itself was deemed invalid based on the criteria of that the DPoP proof itself was deemed invalid based on the
Section 4.3. criteria of Section 4.3.
* An error_description parameter ([RFC6750], Section 3) MAY be * An error_description parameter ([RFC6750], Section 3) MAY be
included along with the error parameter to provide developers a included along with the error parameter to provide developers a
human-readable explanation that is not meant to be displayed to human-readable explanation that is not meant to be displayed to
end-users. end-users.
* An algs parameter SHOULD be included to signal to the client the * An algs parameter SHOULD be included to signal to the client the
JWS algorithms that are acceptable for the DPoP proof JWT. The JWS algorithms that are acceptable for the DPoP proof JWT. The
value of the parameter is a space-delimited list of JWS alg value of the parameter is a space-delimited list of JWS alg
(Algorithm) header values ([RFC7515], Section 4.1.1). (Algorithm) header values ([RFC7515], Section 4.1.1).
* Additional authentication parameters MAY be used and unknown * Additional authentication parameters MAY be used, and unknown
parameters MUST be ignored by recipients. parameters MUST be ignored by recipients.
For example, in response to a protected resource request without Figure 15 shows a response to a protected resource request without
authentication: authentication.
HTTP/1.1 401 Unauthorized HTTP/1.1 401 Unauthorized
WWW-Authenticate: DPoP algs="ES256 PS256" WWW-Authenticate: DPoP algs="ES256 PS256"
Figure 15: HTTP 401 Response to a Protected Resource Request without Figure 15: HTTP 401 Response to a Protected Resource Request without
Authentication Authentication
And in response to a protected resource request that was rejected Figure 16 shows a response to a protected resource request that was
because the confirmation of the DPoP binding in the access token rejected due to the failed confirmation of the DPoP binding in the
failed (with '\' line wrapping per RFC 8792): access token. Figure 16 uses "\" line wrapping per [RFC8792].
HTTP/1.1 401 Unauthorized HTTP/1.1 401 Unauthorized
WWW-Authenticate: DPoP error="invalid_token", \ WWW-Authenticate: DPoP error="invalid_token", \
error_description="Invalid DPoP key binding", algs="ES256" error_description="Invalid DPoP key binding", algs="ES256"
Figure 16: HTTP 401 Response to a Protected Resource Request with Figure 16: HTTP 401 Response to a Protected Resource Request with
an Invalid Token an Invalid Token
Note that browser-based client applications using CORS [WHATWG.Fetch] Note that browser-based client applications using Cross-Origin
only have access to CORS-safelisted response HTTP headers by default. Resource Sharing (CORS) [WHATWG.Fetch] only have access to CORS-
In order for the application to obtain and use the WWW-Authenticate safelisted response HTTP headers by default. In order for the
HTTP response header value, the server needs to make it available to application to obtain and use the WWW-Authenticate HTTP response
the application by including WWW-Authenticate in the Access-Control- header value, the server needs to make it available to the
application by including WWW-Authenticate in the Access-Control-
Expose-Headers response header list value. Expose-Headers response header list value.
This authentication scheme is for origin-server authentication only. This authentication scheme is for origin-server authentication only.
Therefore, this authentication scheme MUST NOT be used with the Therefore, this authentication scheme MUST NOT be used with the
Proxy-Authenticate or Proxy-Authorization header fields. Proxy-Authenticate or Proxy-Authorization header fields.
Note that the syntax of the Authorization header field for this Note that the syntax of the Authorization header field for this
authentication scheme follows the usage of the Bearer scheme defined authentication scheme follows the usage of the Bearer scheme defined
in Section 2.1 of [RFC6750]. While not the preferred credential in Section 2.1 of [RFC6750]. While it is not the preferred
syntax of [RFC9110], it is compatible with the general authentication credential syntax of [RFC9110], it is compatible with the general
framework therein and was used for consistency and familiarity with authentication framework therein and is used for consistency and
the Bearer scheme. familiarity with the Bearer scheme.
7.2. Compatibility with the Bearer Authentication Scheme 7.2. Compatibility with the Bearer Authentication Scheme
Protected resources simultaneously supporting both the DPoP and Protected resources simultaneously supporting both the DPoP and
Bearer schemes need to update how evaluation of bearer tokens is Bearer schemes need to update how the evaluation process is performed
performed to prevent downgraded usage of a DPoP-bound access token. for bearer tokens to prevent downgraded usage of a DPoP-bound access
Specifically, such a protected resource MUST reject a DPoP-bound token. Specifically, such a protected resource MUST reject a DPoP-
access token received as a bearer token per [RFC6750]. bound access token received as a bearer token per [RFC6750].
Section 11.6.1 of [RFC9110] allows a protected resource to indicate Section 11.6.1 of [RFC9110] allows a protected resource to indicate
support for multiple authentication schemes (i.e., Bearer and DPoP) support for multiple authentication schemes (i.e., Bearer and DPoP)
with the WWW-Authenticate header field of a 401 (Unauthorized) with the WWW-Authenticate header field of a 401 (Unauthorized)
response. response.
A protected resource that supports only [RFC6750] and is unaware of A protected resource that supports only [RFC6750] and is unaware of
DPoP would most presumably accept a DPoP-bound access token as a DPoP would most presumably accept a DPoP-bound access token as a
bearer token (JWT [RFC7519] says to ignore unrecognized claims, bearer token (JWT [RFC7519] says to ignore unrecognized claims,
Introspection [RFC7662] says that other parameters might be present Introspection [RFC7662] says that other parameters might be present
while placing no functional requirements on their presence, and while placing no functional requirements on their presence, and
[RFC6750] is effectively silent on the content of the access token as [RFC6750] is effectively silent on the content of the access token
it relates to validity). As such, a client can send a DPoP-bound since it relates to validity). As such, a client can send a DPoP-
access token using the Bearer scheme upon receipt of a WWW- bound access token using the Bearer scheme upon receipt of a WWW-
Authenticate: Bearer challenge from a protected resource (or if it Authenticate: Bearer challenge from a protected resource (or it can
has prior such knowledge about the capabilities of the protected send a DPoP-bound access token if it has prior knowledge of the
resource). The effect of this likely simplifies the logistics of capabilities of the protected resource). The effect of this likely
phased upgrades to protected resources in their support DPoP or even simplifies the logistics of phased upgrades to protected resources in
prolonged deployments of protected resources with mixed token type their support DPoP or prolonged deployments of protected resources
support. with mixed token type support.
If a protected resource supporting both Bearer and DPoP schemes If a protected resource supporting both Bearer and DPoP schemes
elects to respond with multiple WWW-Authenticate challenges, elects to respond with multiple WWW-Authenticate challenges,
attention should be paid to which challenge(s) should deliver the attention should be paid to which challenge(s) should deliver the
actual error information. It is RECOMMENDED that the following rules actual error information. It is RECOMMENDED that the following rules
be adhered to: be adhered to:
* If no authentication information has been included with the * If no authentication information has been included with the
request, then the challenges SHOULD NOT include an error code or request, then the challenges SHOULD NOT include an error code or
other error information, as per [RFC6750], Section 3.1 other error information, as per Section 3.1 of [RFC6750]
(Figure 17). (Figure 17).
* If the mechanism used to attempt authentication could be * If the mechanism used to attempt authentication could be
established unambiguously, then the corresponding challenge SHOULD established unambiguously, then the corresponding challenge SHOULD
be used to deliver error information (Figure 18). be used to deliver error information (Figure 18).
* Otherwise, both Bearer and DPoP challenged MAY be used to deliver * Otherwise, both Bearer and DPoP challenges MAY be used to deliver
error information (Figure 19). error information (Figure 19).
(Where needed, the following examples use '\' line wrapping per RFC The following examples use "\" line wrapping per [RFC8792].
8792.)
GET /protectedresource HTTP/1.1 GET /protectedresource HTTP/1.1
Host: resource.example.org Host: resource.example.org
HTTP/1.1 401 Unauthorized HTTP/1.1 401 Unauthorized
WWW-Authenticate: Bearer, DPoP algs="ES256 PS256" WWW-Authenticate: Bearer, DPoP algs="ES256 PS256"
Figure 17: HTTP 401 Response to a Protected Resource Request without Figure 17: HTTP 401 Response to a Protected Resource Request without
Authentication Authentication
skipping to change at page 24, line 22 skipping to change at line 1058
error_description="Multiple methods used to include access token", \ error_description="Multiple methods used to include access token", \
DPoP algs="ES256 PS256", error="invalid_request", \ DPoP algs="ES256 PS256", error="invalid_request", \
error_description="Multiple methods used to include access token" error_description="Multiple methods used to include access token"
Figure 19: HTTP 400 Response to a Protected Resource Request with Figure 19: HTTP 400 Response to a Protected Resource Request with
Ambiguous Authentication Ambiguous Authentication
7.3. Client Considerations 7.3. Client Considerations
Authorization including a DPoP proof may not be idempotent (depending Authorization including a DPoP proof may not be idempotent (depending
on server enforcement of jti, iat and nonce claims). Consequently, on server enforcement of jti, iat, and nonce claims). Consequently,
all previously idempotent requests for protected resources that were all previously idempotent requests for protected resources that were
previously idempotent may no longer be idempotent. It is RECOMMENDED previously idempotent may no longer be idempotent. It is RECOMMENDED
that clients generate a unique DPoP proof even when retrying that clients generate a unique DPoP proof, even when retrying
idempotent requests in response to HTTP errors generally understood idempotent requests in response to HTTP errors generally understood
as transient. as transient.
Clients that encounter frequent network errors may experience Clients that encounter frequent network errors may experience
additional challenges when interacting with servers with more strict additional challenges when interacting with servers with stricter
nonce validation implementations. nonce validation implementations.
8. Authorization Server-Provided Nonce 8. Authorization Server-Provided Nonce
This section specifies a mechanism using opaque nonces provided by This section specifies a mechanism using opaque nonces provided by
the server that can be used to limit the lifetime of DPoP proofs. the server that can be used to limit the lifetime of DPoP proofs.
Without employing such a mechanism, a malicious party controlling the Without employing such a mechanism, a malicious party controlling the
client (including potentially the end-user) can create DPoP proofs client (potentially including the end-user) can create DPoP proofs
for use arbitrarily far in the future. for use arbitrarily far in the future.
Including a nonce value contributed by the authorization server in Including a nonce value contributed by the authorization server in
the DPoP proof MAY be used by authorization servers to limit the the DPoP proof MAY be used by authorization servers to limit the
lifetime of DPoP proofs. The server determines when and if to issue lifetime of DPoP proofs. The server determines when to issue a new
a new DPoP nonce challenge thereby requiring the use of the nonce DPoP nonce challenge and if it is needed, thereby requiring the use
value in subsequent DPoP proofs. The logic through which the server of the nonce value in subsequent DPoP proofs. The logic through
makes that determination is out of scope of this document. which the server makes that determination is out of scope of this
document.
An authorization server MAY supply a nonce value to be included by An authorization server MAY supply a nonce value to be included by
the client in DPoP proofs sent. In this case, the authorization the client in DPoP proofs sent. In this case, the authorization
server responds to requests not including a nonce with an HTTP 400 server responds to requests that do not include a nonce with an HTTP
(Bad Request) error response per Section 5.2 of [RFC6749] using 400 (Bad Request) error response per Section 5.2 of [RFC6749] using
use_dpop_nonce as the error code value. The authorization server use_dpop_nonce as the error code value. The authorization server
includes a DPoP-Nonce HTTP header in the response supplying a nonce includes a DPoP-Nonce HTTP header in the response supplying a nonce
value to be used when sending the subsequent request. Nonce values value to be used when sending the subsequent request. Nonce values
MUST be unpredictable. This same error code is used when supplying a MUST be unpredictable. This same error code is used when supplying a
new nonce value when there was a nonce mismatch. The client will new nonce value when there was a nonce mismatch. The client will
typically retry the request with the new nonce value supplied upon typically retry the request with the new nonce value supplied upon
receiving a use_dpop_nonce error with an accompanying nonce value. receiving a use_dpop_nonce error with an accompanying nonce value.
For example, in response to a token request without a nonce when the For example, in response to a token request without a nonce when the
authorization server requires one, the authorization server can authorization server requires one, the authorization server can
skipping to change at page 25, line 32 skipping to change at line 1118
"Authorization server requires nonce in DPoP proof" "Authorization server requires nonce in DPoP proof"
} }
Figure 20: HTTP 400 Response to a Token Request without a Nonce Figure 20: HTTP 400 Response to a Token Request without a Nonce
Other HTTP headers and JSON fields MAY also be included in the error Other HTTP headers and JSON fields MAY also be included in the error
response, but there MUST NOT be more than one DPoP-Nonce header. response, but there MUST NOT be more than one DPoP-Nonce header.
Upon receiving the nonce, the client is expected to retry its token Upon receiving the nonce, the client is expected to retry its token
request using a DPoP proof including the supplied nonce value in the request using a DPoP proof including the supplied nonce value in the
nonce claim of the DPoP proof. An example unencoded JWT Payload of nonce claim of the DPoP proof. An example unencoded JWT payload of
such a DPoP proof including a nonce is: such a DPoP proof including a nonce is shown below.
{ {
"jti": "-BwC3ESc6acc2lTc", "jti": "-BwC3ESc6acc2lTc",
"htm": "POST", "htm": "POST",
"htu": "https://server.example.com/token", "htu": "https://server.example.com/token",
"iat": 1562262616, "iat": 1562262616,
"nonce": "eyJ7S_zG.eyJH0-Z.HX4w-7v" "nonce": "eyJ7S_zG.eyJH0-Z.HX4w-7v"
} }
Figure 21: DPoP Proof Payload Including a Nonce Value Figure 21: DPoP Proof Payload including a Nonce Value
The nonce is opaque to the client. The nonce is opaque to the client.
If the nonce claim in the DPoP proof does not exactly match a nonce If the nonce claim in the DPoP proof does not exactly match a nonce
recently supplied by the authorization server to the client, the recently supplied by the authorization server to the client, the
authorization server MUST reject the request. The rejection response authorization server MUST reject the request. The rejection response
MAY include a DPoP-Nonce HTTP header providing a new nonce value to MAY include a DPoP-Nonce HTTP header providing a new nonce value to
use for subsequent requests. use for subsequent requests.
The intent is that clients need to keep only one nonce value and The intent is that clients need to keep only one nonce value and
servers keep a window of recent nonces. That said, transient servers need to keep a window of recent nonces. That said, transient
circumstances may arise in which the server's and client's stored circumstances may arise in which the stored nonce values for the
nonce values differ. However, this situation is self-correcting; server and the client differ. However, this situation is self-
with any rejection message, the server can send the client the nonce correcting. With any rejection message, the server can send the
value that the server wants it to use and the client can store that client the nonce value it wants to use to the client, and the client
nonce value and retry the request with it. Even if the client and/or can store that nonce value and retry the request with it. Even if
server discard their stored nonce values, that situation is also the client and/or server discard their stored nonce values, that
self-correcting because new nonce values can be communicated when situation is also self-correcting because new nonce values can be
responding to or retrying failed requests. communicated when responding to or retrying failed requests.
Note that browser-based client applications using CORS [WHATWG.Fetch] Note that browser-based client applications using CORS [WHATWG.Fetch]
only have access to CORS-safelisted response HTTP headers by default. only have access to CORS-safelisted response HTTP headers by default.
In order for the application to obtain and use the DPoP-Nonce HTTP In order for the application to obtain and use the DPoP-Nonce HTTP
response header value, the server needs to make it available to the response header value, the server needs to make it available to the
application by including DPoP-Nonce in the Access-Control-Expose- application by including DPoP-Nonce in the Access-Control-Expose-
Headers response header list value. Headers response header list value.
8.1. Nonce Syntax 8.1. Nonce Syntax
The nonce syntax in ABNF as used by [RFC6749] (which is the same as The nonce syntax in ABNF as used by [RFC6749] (which is the same as
the scope-token syntax) is: the scope-token syntax) is shown below.
nonce = 1*NQCHAR nonce = 1*NQCHAR
Figure 22: Nonce ABNF Figure 22: Nonce ABNF
8.2. Providing a New Nonce Value 8.2. Providing a New Nonce Value
It is up to the authorization server when to supply a new nonce value It is up to the authorization server when to supply a new nonce value
for the client to use. The client is expected to use the existing for the client to use. The client is expected to use the existing
supplied nonce in DPoP proofs until the server supplies a new nonce supplied nonce in DPoP proofs until the server supplies a new nonce
value. value.
The authorization server MAY supply the new nonce in the same way The authorization server MAY supply the new nonce in the same way
that the initial one was supplied: by using a DPoP-Nonce HTTP header that the initial one was supplied: by using a DPoP-Nonce HTTP header
in the response. The DPoP-Nonce HTTP header field uses the nonce in the response. The DPoP-Nonce HTTP header field uses the nonce
syntax defined in Section 8.1. Of course, each time this happens it syntax defined in Section 8.1. Each time this happens, it requires
requires an extra protocol round trip. an extra protocol round trip.
A more efficient manner of supplying a new nonce value is also A more efficient manner of supplying a new nonce value is also
defined -- by including a DPoP-Nonce HTTP header in the HTTP 200 (OK) defined by including a DPoP-Nonce HTTP header in the HTTP 200 (OK)
response from the previous request. The client MUST use the new response from the previous request. The client MUST use the new
nonce value supplied for the next token request, and for all nonce value supplied for the next token request and for all
subsequent token requests until the authorization server supplies a subsequent token requests until the authorization server supplies a
new nonce. new nonce.
Responses that include the DPoP-Nonce HTTP header should be Responses that include the DPoP-Nonce HTTP header should be
uncacheable (e.g., using Cache-Control: no-store in response to a GET uncacheable (e.g., using Cache-Control: no-store in response to a GET
request) to prevent the response being used to serve a subsequent request) to prevent the response from being used to serve a
request and a stale nonce value being used as a result. subsequent request and a stale nonce value from being used as a
result.
An example 200 OK response providing a new nonce value is: An example 200 OK response providing a new nonce value is shown
below.
HTTP/1.1 200 OK HTTP/1.1 200 OK
Cache-Control: no-store Cache-Control: no-store
DPoP-Nonce: eyJ7S_zG.eyJbYu3.xQmBj-1 DPoP-Nonce: eyJ7S_zG.eyJbYu3.xQmBj-1
Figure 23: HTTP 200 Response Providing the Next Nonce Value Figure 23: HTTP 200 Response Providing the Next Nonce Value
9. Resource Server-Provided Nonce 9. Resource Server-Provided Nonce
Resource servers can also choose to provide a nonce value to be Resource servers can also choose to provide a nonce value to be
included in DPoP proofs sent to them. They provide the nonce using included in DPoP proofs sent to them. They provide the nonce using
the DPoP-Nonce header in the same way that authorization servers do the DPoP-Nonce header in the same way that authorization servers do
as described in Section 8 and Section 8.2. The error signaling is as described in Sections 8 and 8.2. The error signaling is performed
performed as described in Section 7.1. Resource servers use an HTTP as described in Section 7.1. Resource servers use an HTTP 401
401 (Unauthorized) error code with an accompanying WWW-Authenticate: (Unauthorized) error code with an accompanying WWW-Authenticate: DPoP
DPoP value and DPoP-Nonce value to accomplish this. value and DPoP-Nonce value to accomplish this.
For example, in response to a resource request without a nonce when For example, in response to a resource request without a nonce when
the resource server requires one, the resource server can respond the resource server requires one, the resource server can respond
with a DPoP-Nonce value such as the following to provide a nonce with a DPoP-Nonce value such as the following to provide a nonce
value to include in the DPoP proof (with '\' line wrapping per RFC value to include in the DPoP proof. The example below uses "\" line
8792): wrapping per [RFC8792].
HTTP/1.1 401 Unauthorized HTTP/1.1 401 Unauthorized
WWW-Authenticate: DPoP error="use_dpop_nonce", \ WWW-Authenticate: DPoP error="use_dpop_nonce", \
error_description="Resource server requires nonce in DPoP proof" error_description="Resource server requires nonce in DPoP proof"
DPoP-Nonce: eyJ7S_zG.eyJH0-Z.HX4w-7v DPoP-Nonce: eyJ7S_zG.eyJH0-Z.HX4w-7v
Figure 24: HTTP 401 Response to a Resource Request without a Nonce Figure 24: HTTP 401 Response to a Resource Request without a Nonce
Note that the nonces provided by an authorization server and a Note that the nonces provided by an authorization server and a
resource server are different and should not be confused with one resource server are different and should not be confused with one
another, since nonces will be only accepted by the server that issued another since nonces will be only accepted by the server that issued
them. Likewise, should a client use multiple authorization servers them. Likewise, should a client use multiple authorization servers
and/or resource servers, a nonce issued by any of them should be used and/or resource servers, a nonce issued by any of them should be used
only at the issuing server. Developers should also take care to not only at the issuing server. Developers should also be careful to not
confuse DPoP nonces with the OpenID Connect [OpenID.Core] ID Token confuse DPoP nonces with the OpenID Connect [OpenID.Core] ID Token
nonce. nonce.
10. Authorization Code Binding to DPoP Key 10. Authorization Code Binding to a DPoP Key
Binding the authorization code issued to the client's proof-of- Binding the authorization code issued to the client's proof-of-
possession key can enable end-to-end binding of the entire possession key can enable end-to-end binding of the entire
authorization flow. This specification defines the dpop_jkt authorization flow. This specification defines the dpop_jkt
authorization request parameter for this purpose. The value of the authorization request parameter for this purpose. The value of the
dpop_jkt authorization request parameter is the JSON Web Key (JWK) dpop_jkt authorization request parameter is the JWK Thumbprint
Thumbprint [RFC7638] of the proof-of-possession public key using the [RFC7638] of the proof-of-possession public key using the SHA-256
SHA-256 hash function - the same value as used for the jkt hash function, which is the same value as used for the jkt
confirmation method defined in Section 6.1. confirmation method defined in Section 6.1.
When a token request is received, the authorization server computes When a token request is received, the authorization server computes
the JWK thumbprint of the proof-of-possession public key in the DPoP the JWK Thumbprint of the proof-of-possession public key in the DPoP
proof and verifies that it matches the dpop_jkt parameter value in proof and verifies that it matches the dpop_jkt parameter value in
the authorization request. If they do not match, it MUST reject the the authorization request. If they do not match, it MUST reject the
request. request.
An example authorization request using the dpop_jkt authorization An example authorization request using the dpop_jkt authorization
request parameter follows (with '\' line wrapping per RFC 8792): request parameter is shown below and uses "\" line wrapping per
[RFC8792].
GET /authorize?response_type=code&client_id=s6BhdRkqt3&state=xyz\ GET /authorize?response_type=code&client_id=s6BhdRkqt3&state=xyz\
&redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb\ &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb\
&code_challenge=E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM\ &code_challenge=E9Melhoa2OwvFrEMTJguCHaoeK1t8URWbuGJSstw-cM\
&code_challenge_method=S256\ &code_challenge_method=S256\
&dpop_jkt=NzbLsXh8uDCcd-6MNwXF4W_7noWXFZAfHkxZsRGC9Xs HTTP/1.1 &dpop_jkt=NzbLsXh8uDCcd-6MNwXF4W_7noWXFZAfHkxZsRGC9Xs HTTP/1.1
Host: server.example.com Host: server.example.com
Figure 25: Authorization Request using the dpop_jkt Parameter Figure 25: Authorization Request Using the dpop_jkt Parameter
Use of the dpop_jkt authorization request parameter is OPTIONAL. Use of the dpop_jkt authorization request parameter is OPTIONAL.
Note that the dpop_jkt authorization request parameter MAY also be Note that the dpop_jkt authorization request parameter MAY also be
used in combination with PKCE [RFC7636], which is recommended by used in combination with Proof Key for Code Exchange (PKCE)
[I-D.ietf-oauth-security-topics] as a countermeasure to authorization [RFC7636], which is recommended by [SECURITY-TOPICS] as a
code injection. The dpop_jkt authorization request parameter only countermeasure to authorization code injection. The dpop_jkt
provides similar protections when a unique DPoP key is used for each authorization request parameter only provides similar protections
authorization request. when a unique DPoP key is used for each authorization request.
10.1. DPoP with Pushed Authorization Requests 10.1. DPoP with Pushed Authorization Requests
When Pushed Authorization Requests (PAR, [RFC9126]) are used in When Pushed Authorization Requests (PARs) [RFC9126] are used in
conjunction with DPoP, there are two ways in which the DPoP key can conjunction with DPoP, there are two ways in which the DPoP key can
be communicated in the PAR request: be communicated in the PAR request:
* The dpop_jkt parameter can be used as described in Section 10 to * The dpop_jkt parameter can be used as described in Section 10 to
bind the issued authorization code to a specific key. In this bind the issued authorization code to a specific key. In this
case, dpop_jkt MUST be included alongside other authorization case, dpop_jkt MUST be included alongside other authorization
request parameters in the POST body of the PAR request. request parameters in the POST body of the PAR request.
* Alternatively, the DPoP header can be added to the PAR request. * Alternatively, the DPoP header can be added to the PAR request.
In this case, the authorization server MUST check the provided In this case, the authorization server MUST check the provided
DPoP proof JWT as defined in Section 4.3. It MUST further behave DPoP proof JWT as defined in Section 4.3. It MUST further behave
as if the contained public key's thumbprint was provided using as if the contained public key's thumbprint was provided using
dpop_jkt, i.e., reject the subsequent token request unless a DPoP dpop_jkt, i.e., reject the subsequent token request unless a DPoP
proof for the same key is provided. This can help to simplify the proof for the same key is provided. This can help to simplify the
implementation of the client, as it can "blindly" attach the DPoP implementation of the client, as it can "blindly" attach the DPoP
header to all requests to the authorization server regardless of header to all requests to the authorization server regardless of
the type of request. Additionally, it provides a stronger the type of request. Additionally, it provides a stronger
binding, as the DPoP header contains a proof of possession of the binding, as the DPoP header contains a proof of possession of the
private key. private key.
Both mechanisms MUST be supported by an authorization server that Both mechanisms MUST be supported by an authorization server that
supports PAR and DPoP. If both mechanisms are used at the same time, supports PAR and DPoP. If both mechanisms are used at the same time,
the authorization server MUST reject the request if the JWK the authorization server MUST reject the request if the JWK
Thumbprint in dpop_jkt does not match the public key in the DPoP Thumbprint in dpop_jkt does not match the public key in the DPoP
header. header.
Allowing both mechanisms ensures that clients that use dpop_jkt do Allowing both mechanisms ensures that clients using dpop_jkt do not
not need to distinguish between front-channel and pushed need to distinguish between front-channel and pushed authorization
authorization requests, and at the same time, clients that only have requests, and at the same time, clients that only have one code path
one code path for protecting all calls to authorization server for protecting all calls to authorization server endpoints do not
endpoints do not need to distinguish between requests to the PAR need to distinguish between requests to the PAR endpoint and the
endpoint and the token endpoint. token endpoint.
11. Security Considerations 11. Security Considerations
In DPoP, the prevention of token replay at a different endpoint (see In DPoP, the prevention of token replay at a different endpoint (see
Section 2) is achieved through authentication of the server per Section 2) is achieved through authentication of the server per
[RFC6125] and binding of the DPoP proof to a certain URI and HTTP [RFC6125] and the binding of the DPoP proof to a certain URI and HTTP
method. DPoP, however, has a somewhat different nature of protection method. However, DPoP has a somewhat different nature of protection
than TLS-based methods such as OAuth Mutual TLS [RFC8705] or OAuth than TLS-based methods such as OAuth Mutual TLS [RFC8705] or OAuth
Token Binding [I-D.ietf-oauth-token-binding] (see also Section 11.1 Token Binding [TOKEN-BINDING] (see also Sections 11.1 and 11.7).
and Section 11.7). TLS-based mechanisms can leverage a tight TLS-based mechanisms can leverage a tight integration between the TLS
integration between the TLS layer and the application layer to layer and the application layer to achieve strong message integrity,
achieve strong message integrity, authenticity, and replay authenticity, and replay protection.
protection.
11.1. DPoP Proof Replay 11.1. DPoP Proof Replay
If an adversary is able to get hold of a DPoP proof JWT, the If an adversary is able to get hold of a DPoP proof JWT, the
adversary could replay that token at the same endpoint (the HTTP adversary could replay that token at the same endpoint (the HTTP
endpoint and method are enforced via the respective claims in the endpoint and method are enforced via the respective claims in the
JWTs). To limit this, servers MUST only accept DPoP proofs for a JWTs). To limit this, servers MUST only accept DPoP proofs for a
limited time after their creation (preferably only for a relatively limited time after their creation (preferably only for a relatively
brief period on the order of seconds or minutes). brief period on the order of seconds or minutes).
To prevent multiple uses of the same DPoP proof, servers can store, In the context of the target URI, servers can store the jti value of
in the context of the target URI, the jti value of each DPoP proof each DPoP proof for the time window in which the respective DPoP
for the time window in which the respective DPoP proof JWT would be proof JWT would be accepted to prevent multiple uses of the same DPoP
accepted. HTTP requests to the same URI for which the jti value has proof. HTTP requests to the same URI for which the jti value has
been seen before would be declined. Such a single-use check, when been seen before would be declined. When strictly enforced, such a
strictly enforced, provides a very strong protection against DPoP single-use check provides a very strong protection against DPoP proof
proof replay, but may not always be feasible in practice, e.g., when replay, but it may not always be feasible in practice, e.g., when
multiple servers behind a single endpoint have no shared state. multiple servers behind a single endpoint have no shared state.
In order to guard against memory exhaustion attacks, a server that is In order to guard against memory exhaustion attacks, a server that is
tracking jti values should reject DPoP proof JWTs with unnecessarily tracking jti values should reject DPoP proof JWTs with unnecessarily
large jti values or store only a hash thereof. large jti values or store only a hash thereof.
Note: To accommodate for clock offsets, the server MAY accept DPoP Note: To accommodate for clock offsets, the server MAY accept DPoP
proofs that carry an iat time in the reasonably near future (on the proofs that carry an iat time in the reasonably near future (on the
order of seconds or minutes). Because clock skews between servers order of seconds or minutes). Because clock skews between servers
and clients may be large, servers MAY limit DPoP proof lifetimes by and clients may be large, servers MAY limit DPoP proof lifetimes by
using server-provided nonce values containing the time at the server using server-provided nonce values containing the time at the server
rather than comparing the client-supplied iat time to the time at the rather than comparing the client-supplied iat time to the time at the
server. Nonces created in this way yield the same result even in the server. Nonces created in this way yield the same result even in the
face of arbitrarily large clock skews. face of arbitrarily large clock skews.
Server-provided nonces are an effective means for further reducing Server-provided nonces are an effective means for further reducing
the chances for successful DPoP proof replay. Unlike cryptographic the chances for successful DPoP proof replay. Unlike cryptographic
nonces, it is acceptable for clients to use the same nonce multiple nonces, it is acceptable for clients to use the same nonce multiple
times, and for the server to accept the same nonce multiple times. times and for the server to accept the same nonce multiple times. As
As long as the jti value is tracked and duplicates rejected for the long as the jti value is tracked and duplicates are rejected for the
lifetime of the nonce, there is no additional risk of token replay. lifetime of the nonce, there is no additional risk of token replay.
11.2. DPoP Proof Pre-Generation 11.2. DPoP Proof Pre-generation
An attacker in control of the client can pre-generate DPoP proofs for An attacker in control of the client can pre-generate DPoP proofs for
specific endpoints arbitrarily far into the future by choosing the specific endpoints arbitrarily far into the future by choosing the
iat value in the DPoP proof to be signed by the proof-of-possession iat value in the DPoP proof to be signed by the proof-of-possession
key. Note that one such attacker is the person who is the legitimate key. Note that one such attacker is the person who is the legitimate
user of the client. The user may pre-generate DPoP proofs to user of the client. The user may pre-generate DPoP proofs to
exfiltrate from the machine possessing the proof-of-possession key exfiltrate from the machine possessing the proof-of-possession key
upon which they were generated and copy them to another machine that upon which they were generated and copy them to another machine that
does not possess the key. For instance, a bank employee might pre- does not possess the key. For instance, a bank employee might pre-
generate DPoP proofs on a bank computer and then copy them to another generate DPoP proofs on a bank computer and then copy them to another
skipping to change at page 31, line 28 skipping to change at line 1399
11.3. DPoP Nonce Downgrade 11.3. DPoP Nonce Downgrade
A server MUST NOT accept any DPoP proofs without the nonce claim when A server MUST NOT accept any DPoP proofs without the nonce claim when
a DPoP nonce has been provided to the client. a DPoP nonce has been provided to the client.
11.4. Untrusted Code in the Client Context 11.4. Untrusted Code in the Client Context
If an adversary is able to run code in the client's execution If an adversary is able to run code in the client's execution
context, the security of DPoP is no longer guaranteed. Common issues context, the security of DPoP is no longer guaranteed. Common issues
in web applications leading to the execution of untrusted code are in web applications leading to the execution of untrusted code are
cross-site scripting and remote code inclusion attacks. XSS and remote code inclusion attacks.
If the private key used for DPoP is stored in such a way that it If the private key used for DPoP is stored in such a way that it
cannot be exported, e.g., in a hardware or software security module, cannot be exported, e.g., in a hardware or software security module,
the adversary cannot exfiltrate the key and use it to create the adversary cannot exfiltrate the key and use it to create
arbitrary DPoP proofs. The adversary can, however, create new DPoP arbitrary DPoP proofs. The adversary can, however, create new DPoP
proofs as long as the client is online, and use these proofs proofs as long as the client is online and uses these proofs
(together with the respective tokens) either on the victim's device (together with the respective tokens) either on the victim's device
or on a device under the attacker's control to send arbitrary or on a device under the attacker's control to send arbitrary
requests that will be accepted by servers. requests that will be accepted by servers.
To send requests even when the client is offline, an adversary can To send requests even when the client is offline, an adversary can
try to pre-compute DPoP proofs using timestamps in the future and try to pre-compute DPoP proofs using timestamps in the future and
exfiltrate these together with the access or refresh token. exfiltrate these together with the access or refresh token.
An adversary might further try to associate tokens issued from the An adversary might further try to associate tokens issued from the
token endpoint with a key pair under the adversary's control. One token endpoint with a key pair under the adversary's control. One
skipping to change at page 32, line 20 skipping to change at line 1429
This grant needs to be "silent", i.e., not require interaction with This grant needs to be "silent", i.e., not require interaction with
the user. With code running in the client's origin, the adversary the user. With code running in the client's origin, the adversary
has access to the resulting authorization code and can use it to has access to the resulting authorization code and can use it to
associate their own DPoP keys with the tokens returned from the token associate their own DPoP keys with the tokens returned from the token
endpoint. The adversary is then able to use the resulting tokens on endpoint. The adversary is then able to use the resulting tokens on
their own device even if the client is offline. their own device even if the client is offline.
Therefore, protecting clients against the execution of untrusted code Therefore, protecting clients against the execution of untrusted code
is extremely important even if DPoP is used. Besides secure coding is extremely important even if DPoP is used. Besides secure coding
practices, Content Security Policy [W3C.CSP] can be used as a second practices, Content Security Policy [W3C.CSP] can be used as a second
layer of defense against cross-site scripting. layer of defense against XSS.
11.5. Signed JWT Swapping 11.5. Signed JWT Swapping
Servers accepting signed DPoP proof JWTs MUST verify that the typ Servers accepting signed DPoP proof JWTs MUST verify that the typ
field is dpop+jwt in the headers of the JWTs to ensure that field is dpop+jwt in the headers of the JWTs to ensure that
adversaries cannot use JWTs created for other purposes. adversaries cannot use JWTs created for other purposes.
11.6. Signature Algorithms 11.6. Signature Algorithms
Implementers MUST ensure that only asymmetric digital signature Implementers MUST ensure that only asymmetric digital signature
algorithms (such as ES256) that are deemed secure can be used for algorithms (such as ES256) that are deemed secure can be used for
signing DPoP proofs. In particular, the algorithm none MUST NOT be signing DPoP proofs. In particular, the algorithm none MUST NOT be
allowed. allowed.
11.7. Request Integrity 11.7. Request Integrity
DPoP does not ensure the integrity of the payload or headers of DPoP does not ensure the integrity of the payload or headers of
requests. The DPoP proof only contains claims for the HTTP URI and requests. The DPoP proof only contains claims for the HTTP URI and
method, but not, for example, the message body or general request method, but not the message body or general request headers, for
headers. example.
This is an intentional design decision intended to keep DPoP simple This is an intentional design decision intended to keep DPoP simple
to use, but as described, makes DPoP potentially susceptible to to use, but as described, it makes DPoP potentially susceptible to
replay attacks where an attacker is able to modify message contents replay attacks where an attacker is able to modify message contents
and headers. In many setups, the message integrity and and headers. In many setups, the message integrity and
confidentiality provided by TLS is sufficient to provide a good level confidentiality provided by TLS is sufficient to provide a good level
of protection. of protection.
Note: While signatures covering other parts of requests are out of Note: While signatures covering other parts of requests are out of
the scope of this specification, additional information to be signed the scope of this specification, additional information to be signed
can be added into DPoP proofs. can be added into DPoP proofs.
11.8. Access Token and Public Key Binding 11.8. Access Token and Public Key Binding
The binding of the access token to the DPoP public key, which is The binding of the access token to the DPoP public key, as specified
specified in Section 6, uses a cryptographic hash of the JWK in Section 6, uses a cryptographic hash of the JWK representation of
representation of the public key. It relies on the hash function the public key. It relies on the hash function having sufficient
having sufficient second-preimage resistance so as to make it second-preimage resistance so as to make it computationally
computationally infeasible to find or create another key that infeasible to find or create another key that produces to the same
produces to the same hash output value. The SHA-256 hash function hash output value. The SHA-256 hash function was used because it
was used because it meets the aforementioned requirement while being meets the aforementioned requirement while being widely available.
widely available.
Similarly, the binding of the DPoP proof to the access token uses a Similarly, the binding of the DPoP proof to the access token uses a
hash of that access token as the value of the ath claim in the DPoP hash of that access token as the value of the ath claim in the DPoP
proof (see Section 4.2). This relies on the value of the hash being proof (see Section 4.2). This relies on the value of the hash being
sufficiently unique so as to reliably identify the access token. The sufficiently unique so as to reliably identify the access token. The
collision resistance of SHA-256 meets that requirement. collision resistance of SHA-256 meets that requirement.
11.9. Authorization Code and Public Key Binding 11.9. Authorization Code and Public Key Binding
Cryptographic binding of the authorization code to the DPoP public Cryptographic binding of the authorization code to the DPoP public
key, is specified in Section 10. This binding prevents attacks in key is specified in Section 10. This binding prevents attacks in
which the attacker captures the authorization code and creates a DPoP which the attacker captures the authorization code and creates a DPoP
proof using a proof-of-possession key other than that held by the proof using a proof-of-possession key other than the one held by the
client and redeems the authorization code using that DPoP proof. By client and redeems the authorization code using that DPoP proof. By
ensuring end-to-end that only the client's DPoP key can be used, this ensuring end to end that only the client's DPoP key can be used, this
prevents captured authorization codes from being exfiltrated and used prevents captured authorization codes from being exfiltrated and used
at locations other than the one to which the authorization code was at locations other than the one to which the authorization code was
issued. issued.
Authorization codes can, for instance, be harvested by attackers from Authorization codes can, for instance, be harvested by attackers from
places that the HTTP messages containing them are logged. Even when places where the HTTP messages containing them are logged. Even when
efforts are made to make authorization codes one-time-use, in efforts are made to make authorization codes one-time-use, in
practice, there is often a time window during which attackers can practice, there is often a time window during which attackers can
replay them. For instance, when authorization servers are replay them. For instance, when authorization servers are
implemented as scalable replicated services, some replicas may implemented as scalable replicated services, some replicas may
temporarily not yet have the information needed to prevent replay. temporarily not yet have the information needed to prevent replay.
DPoP binding of the authorization code solves these problems. DPoP binding of the authorization code solves these problems.
If an authorization server does not (or cannot) strictly enforce the If an authorization server does not (or cannot) strictly enforce the
single-use limitation for authorization codes and an attacker can single-use limitation for authorization codes and an attacker can
access the authorization code (and if PKCE is used, the access the authorization code (and if PKCE is used, the
code_verifier), the attacker can create a forged token request, code_verifier), the attacker can create a forged token request,
binding the resulting token to an attacker-controlled key. For binding the resulting token to an attacker-controlled key. For
example, using cross-site scripting, attackers might obtain access to example, using XSS, attackers might obtain access to the
the authorization code and PKCE parameters. Use of the dpop_jkt authorization code and PKCE parameters. Use of the dpop_jkt
parameter prevents this attack. parameter prevents this attack.
The binding of the authorization code to the DPoP public key uses a The binding of the authorization code to the DPoP public key uses a
JWK Thumbprint of the public key, just as the access token binding JWK Thumbprint of the public key, just as the access token binding
does. The same JWK Thumbprint considerations apply. does. The same JWK Thumbprint considerations apply.
11.10. Hash Algorithm Agility 11.10. Hash Algorithm Agility
The jkt confirmation method member, the ath JWT claim, and the The jkt confirmation method member, the ath JWT claim, and the
dpop_jkt authorization request parameter defined herein all use the dpop_jkt authorization request parameter defined herein all use the
output of the SHA-256 hash function as their value. The use of a output of the SHA-256 hash function as their value. The use of a
single hash function by this specification was intentional and aimed single hash function by this specification was intentional and aimed
at simplicity and avoidance of potential security and at simplicity and avoidance of potential security and
interoperability issues arising from common mistakes implementing and interoperability issues arising from common mistakes implementing and
deploying parameterized algorithm agility schemes. The use of a deploying parameterized algorithm agility schemes. However, the use
different hash function is not precluded, however, if future of a different hash function is not precluded if future circumstances
circumstances change making SHA-256 insufficient for the requirements change and make SHA-256 insufficient for the requirements of this
of this specification. Should that need arise, it is expected that a specification. Should that need arise, it is expected that a short
short specification be produced that updates this one. That specification will be produced that updates this one. Using the
specification will likely define, using the output of a then output of an appropriate hash function as the value, that
appropriate hash function as the value, a new confirmation method specification will likely define a new confirmation method member, a
member, a new JWT claim, and a new authorization request parameter. new JWT claim, and a new authorization request parameter. These
These items will be used in place of, or alongside, their respective items will be used in place of, or alongside, their respective
counterparts in the same message structures and flows of the larger counterparts in the same message structures and flows of the larger
protocol defined by this specification. protocol defined by this specification.
11.11. Binding to Client Identity 11.11. Binding to Client Identity
In cases where DPoP is used with client authentication, it is only In cases where DPoP is used with client authentication, it is only
bound to authentication by being coincident in the same TLS tunnel. bound to authentication by being coincident in the same TLS tunnel.
Since the DPoP proof is not directly cryptographically bound to the Since the DPoP proof is not directly bound to the authentication
authentication, it's possible that the authentication or the DPoP cryptographically, it's possible that the authentication or the DPoP
messages were copied into the tunnel. While including the URI in the messages were copied into the tunnel. While including the URI in the
DPoP can partially mitigate some of this risk, modifying the DPoP can partially mitigate some of this risk, modifying the
authentication mechanism to provide cryptographic binding between authentication mechanism to provide cryptographic binding between
authentication and DPoP could provide better protection. However, authentication and DPoP could provide better protection. However,
providing additional binding with authentication through the providing additional binding with authentication through the
modification of authentication mechanisms or other means is beyond modification of authentication mechanisms or other means is beyond
the scope of this specification. the scope of this specification.
12. IANA Considerations 12. IANA Considerations
12.1. OAuth Access Token Type Registration 12.1. OAuth Access Token Types Registration
This specification requests registration of the following access IANA has registered the following access token type in the "OAuth
token type in the "OAuth Access Token Types" registry Access Token Types" registry [IANA.OAuth.Params] established by
[IANA.OAuth.Params] established by [RFC6749]. [RFC6749].
* Type name: DPoP Name: DPoP
* Additional Token Endpoint Response Parameters: (none)
* HTTP Authentication Scheme(s): DPoP Additional Token Endpoint Response Parameters: (none)
* Change controller: IETF
* Specification document(s): [[ this specification ]] HTTP Authentication Scheme(s): DPoP
Change Controller: IETF
Reference: RFC 9449
12.2. OAuth Extensions Error Registration 12.2. OAuth Extensions Error Registration
This specification requests registration of the following error IANA has registered the following error values in the "OAuth
values in the "OAuth Extensions Error" registry [IANA.OAuth.Params] Extensions Error" registry [IANA.OAuth.Params] established by
established by [RFC6749]. [RFC6749].
Invalid DPoP proof: Invalid DPoP proof:
* Name: invalid_dpop_proof Name: invalid_dpop_proof
* Usage Location: token error response, resource access error
response Usage Location: token error response, resource access error
* Protocol Extension: Demonstrating Proof of Possession (DPoP) response
* Change controller: IETF
* Specification document(s): [[ this specification ]] Protocol Extension: Demonstrating Proof of Possession (DPoP)
Change Controller: IETF
Reference: RFC 9449
Use DPoP nonce: Use DPoP nonce:
* Name: use_dpop_nonce Name: use_dpop_nonce
* Usage Location: token error response, resource access error
response Usage Location: token error response, resource access error
* Protocol Extension: Demonstrating Proof of Possession (DPoP) response
* Change controller: IETF
* Specification document(s): [[ this specification ]] Protocol Extension: Demonstrating Proof of Possession (DPoP)
Change Controller: IETF
Reference: RFC 9449
12.3. OAuth Parameters Registration 12.3. OAuth Parameters Registration
This specification requests registration of the following IANA has registered the following authorization request parameter in
authorization request parameter in the "OAuth Parameters" registry the "OAuth Parameters" registry [IANA.OAuth.Params] established by
[IANA.OAuth.Params] established by [RFC6749]. [RFC6749].
* Name: dpop_jkt Name: dpop_jkt
* Parameter Usage Location: authorization request
* Change Controller: IETF
* Reference: [[ Section 10 of this specification ]]
12.4. HTTP Authentication Scheme Registration Parameter Usage Location: authorization request
This specification requests registration of the following scheme in Change Controller: IETF
the "Hypertext Transfer Protocol (HTTP) Authentication Scheme
Registry" [RFC9110][IANA.HTTP.AuthSchemes]:
* Authentication Scheme Name: DPoP Reference: Section 10 of RFC 9449
* Reference: [[ Section 7.1 of this specification ]]
12.4. HTTP Authentication Schemes Registration
IANA has registered the following scheme in the "HTTP Authentication
Schemes" registry [IANA.HTTP.AuthSchemes] established by [RFC9110],
Section 16.4.1.
Authentication Scheme Name: DPoP
Reference: Section 7.1 of RFC 9449
12.5. Media Type Registration 12.5. Media Type Registration
This section registers the application/dpop+jwt media type [RFC2046] IANA has registered the application/dpop+jwt media type [RFC2046] in
in the IANA "Media Types" registry [IANA.MediaTypes] in the manner the "Media Types" registry [IANA.MediaTypes] in the manner described
described in [RFC6838], which is used to indicate that the content is in [RFC6838], which is used to indicate that the content is a DPoP
a DPoP JWT. JWT.
* Type name: application Type name: application
* Subtype name: dpop+jwt
* Required parameters: n/a Subtype name: dpop+jwt
* Optional parameters: n/a
* Encoding considerations: binary; A DPoP JWT is a JWT; JWT values Required parameters: n/a
Optional parameters: n/a
Encoding considerations: binary. A DPoP JWT is a JWT; JWT values
are encoded as a series of base64url-encoded values (some of which are encoded as a series of base64url-encoded values (some of which
may be the empty string) separated by period ('.') characters. may be the empty string) separated by period ('.') characters.
* Security considerations: See Section 11 of [[ this specification
]] Security considerations: See Section 11 of RFC 9449
* Interoperability considerations: n/a
* Published specification: [[ this specification ]] Interoperability considerations: n/a
* Applications that use this media type: Applications using [[ this
specification ]] for application-level proof of possession Published specification: RFC 9449
* Fragment identifier considerations: n/a
* Additional information: Applications that use this media type: Applications using RFC 9449
- File extension(s): n/a for application-level proof of possession
- Macintosh file type code(s): n/a
* Person & email address to contact for further information: Michael Fragment identifier considerations: n/a
B. Jones, mbj@microsoft.com
* Intended usage: COMMON Additional information:
* Restrictions on usage: none
* Author: Michael B. Jones, mbj@microsoft.com File extension(s): n/a
* Change controller: IETF Macintosh file type code(s): n/a
* Provisional registration? No
Person & email address to contact for further information: Michael
B. Jones, michael_b_jones@hotmail.com
Intended usage: COMMON
Restrictions on usage: none
Author: Michael B. Jones, michael_b_jones@hotmail.com
Change controller: IETF
12.6. JWT Confirmation Methods Registration 12.6. JWT Confirmation Methods Registration
This specification requests registration of the following value in IANA has registered the following JWT cnf member value in the "JWT
the IANA "JWT Confirmation Methods" registry [IANA.JWT] for JWT cnf Confirmation Methods" registry [IANA.JWT] established by [RFC7800].
member values established by [RFC7800].
* Confirmation Method Value: jkt Confirmation Method Value: jkt
* Confirmation Method Description: JWK SHA-256 Thumbprint
* Change Controller: IETF Confirmation Method Description: JWK SHA-256 Thumbprint
* Specification Document(s): [[ Section 6 of this specification ]]
Change Controller: IETF
Reference: Section 6 of RFC 9449
12.7. JSON Web Token Claims Registration 12.7. JSON Web Token Claims Registration
This specification requests registration of the following Claims in IANA has registered the following Claims in the "JSON Web Token
the IANA "JSON Web Token Claims" registry [IANA.JWT] established by Claims" registry [IANA.JWT] established by [RFC7519].
[RFC7519].
HTTP method: HTTP method:
* Claim Name: htm Claim Name: htm
* Claim Description: The HTTP method of the request
* Change Controller: IETF Claim Description: The HTTP method of the request
* Specification Document(s): [[ Section 4.2 of this specification ]]
Change Controller: IETF
Reference: Section 4.2 of RFC 9449
HTTP URI: HTTP URI:
* Claim Name: htu Claim Name: htu
* Claim Description: The HTTP URI of the request (without query and
fragment parts) Claim Description: The HTTP URI of the request (without query and
* Change Controller: IETF fragment parts)
* Specification Document(s): [[ Section 4.2 of this specification ]]
Change Controller: IETF
Reference: Section 4.2 of RFC 9449
Access token hash: Access token hash:
* Claim Name: ath Claim Name: ath
* Claim Description: The base64url encoded SHA-256 hash of the ASCII
encoding of the associated access token's value
* Change Controller: IETF
* Specification Document(s): [[ Section 4.2 of this specification ]]
12.7.1. "nonce" Registry Update Claim Description: The base64url-encoded SHA-256 hash of the
ASCII encoding of the associated access token's value
Change Controller: IETF
Reference: Section 4.2 of RFC 9449
12.7.1. "nonce" Registration Update
The Internet Security Glossary [RFC4949] provides a useful definition The Internet Security Glossary [RFC4949] provides a useful definition
of nonce as a random or non-repeating value that is included in data of nonce as a random or non-repeating value that is included in data
exchanged by a protocol, usually for the purpose of guaranteeing exchanged by a protocol, usually for the purpose of guaranteeing
liveness and thus detecting and protecting against replay attacks. liveness and thus detecting and protecting against replay attacks.
However, the initial registration of the nonce claim by [OpenID.Core] However, the initial registration of the nonce claim by [OpenID.Core]
used language that was contextually specific to that application, used language that was contextually specific to that application,
which was potentially limiting to its general applicability. which was potentially limiting to its general applicability.
This specification therefore requests that the entry for nonce in the Therefore, IANA has updated the entry for nonce in the "JSON Web
IANA "JSON Web Token Claims" registry [IANA.JWT] be updated as Token Claims" registry [IANA.JWT] with an expanded definition to
follows to reflect that the claim can be used appropriately in other reflect that the claim can be used appropriately in other contexts
contexts. and with the addition of this document as a reference, as follows.
* Claim Name: nonce Claim Name: nonce
* Claim Description: Value used to associate a Client session with
an ID Token (MAY also be used for nonce values in other
applications of JWTs)
* Change Controller: OpenID Foundation Artifact Binding Working
Group - openid-specs-ab@lists.openid.net
* Specification Document(s): Section 2 of [OpenID.Core] and [[ this
specification ]]
12.8. HTTP Message Header Field Names Registration Claim Description: Value used to associate a Client session with an
ID Token (MAY also be used for nonce values in other applications
of JWTs)
This document specifies the following HTTP header fields, Change Controller: OpenID Foundation Artifact Binding Working Group,
registration of which is requested in the "Hypertext Transfer openid-specs-ab@lists.openid.net
Protocol (HTTP) Field Name Registry" registry
[RFC9110][IANA.HTTP.Fields]:
* Field name: DPoP Specification Document(s): Section 2 of [OpenID.Core] and RFC 9449
* Status: permanent 12.8. Hypertext Transfer Protocol (HTTP) Field Name Registration
* Specification document: [[ this specification ]] IANA has registered the following HTTP header fields, as specified by
this document, in the "Hypertext Transfer Protocol (HTTP) Field Name
Registry" [IANA.HTTP.Fields] established by [RFC9110]:
* Field name: DPoP-Nonce DPoP:
* Status: permanent Field Name: DPoP
* Specification document: [[ this specification ]] Status: permanent
Reference: RFC 9449
DPoP-Nonce:
Field Name: DPoP-Nonce
Status: permanent
Reference: RFC 9449
12.9. OAuth Authorization Server Metadata Registration 12.9. OAuth Authorization Server Metadata Registration
This specification requests registration of the following value in IANA has registered the following value in the "OAuth Authorization
the IANA "OAuth Authorization Server Metadata" registry Server Metadata" registry [IANA.OAuth.Params] established by
[IANA.OAuth.Params] established by [RFC8414]. [RFC8414].
* Metadata Name: dpop_signing_alg_values_supported Metadata Name: dpop_signing_alg_values_supported
* Metadata Description: JSON array containing a list of the JWS
Metadata Description: JSON array containing a list of the JWS
algorithms supported for DPoP proof JWTs algorithms supported for DPoP proof JWTs
* Change Controller: IETF
* Specification Document(s): [[ Section 5.1 of this specification ]] Change Controller: IETF
Reference: Section 5.1 of RFC 9449
12.10. OAuth Dynamic Client Registration Metadata 12.10. OAuth Dynamic Client Registration Metadata
This specification requests registration of the following value in IANA has registered the following value in the IANA "OAuth Dynamic
the IANA "OAuth Dynamic Client Registration Metadata" registry Client Registration Metadata" registry [IANA.OAuth.Params]
[IANA.OAuth.Params] established by [RFC7591]. established by [RFC7591].
* Metadata Name: dpop_bound_access_tokens Client Metadata Name: dpop_bound_access_tokens
* Metadata Description: Boolean value specifying whether the client
always uses DPoP for token requests
* Change Controller: IETF
* Specification Document(s): [[ Section 5.2 of this specification ]]
13. Normative References Client Metadata Description: Boolean value specifying whether the
client always uses DPoP for token requests
Change Controller: IETF
Reference: Section 5.2 of RFC 9449
13. References
13.1. Normative References
[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, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005, RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>. <https://www.rfc-editor.org/info/rfc3986>.
skipping to change at page 40, line 15 skipping to change at line 1856
[RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of- [RFC7800] Jones, M., Bradley, J., and H. Tschofenig, "Proof-of-
Possession Key Semantics for JSON Web Tokens (JWTs)", Possession Key Semantics for JSON Web Tokens (JWTs)",
RFC 7800, DOI 10.17487/RFC7800, April 2016, RFC 7800, DOI 10.17487/RFC7800, April 2016,
<https://www.rfc-editor.org/info/rfc7800>. <https://www.rfc-editor.org/info/rfc7800>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[SHS] National Institute of Standards and Technology, "Secure [SHS] National Institute of Standards and Technology, "Secure
Hash Standard (SHS)", FIPS PUB 180-4, August 2015, Hash Standard (SHS)", FIPS PUB 180-4,
<https://nvlpubs.nist.gov/nistpubs/FIPS/ DOI 10.6028/NIST.FIPS.180-4, August 2015,
NIST.FIPS.180-4.pdf>. <http://dx.doi.org/10.6028/NIST.FIPS.180-4>.
14. Informative References 13.2. Informative References
[BREACH] "CVE-2013-3587", <https://cve.mitre.org/cgi-bin/ [BREACH] CVE, "CVE-2013-3587", <https://cve.mitre.org/cgi-bin/
cvename.cgi?name=CVE-2013-3587>. cvename.cgi?name=CVE-2013-3587>.
[CRIME] "CVE-2012-4929", <https://cve.mitre.org/cgi-bin/
cvename.cgi?name=cve-2012-4929>.
[Cloudbleed] [Cloudbleed]
"Incident report on memory leak caused by Cloudflare Graham-Cumming, J., "Incident report on memory leak caused
parser bug", <https://blog.cloudflare.com/incident-report- by Cloudflare parser bug", February 2017,
on-memory-leak-caused-by-cloudflare-parser-bug/>. <https://blog.cloudflare.com/incident-report-on-memory-
leak-caused-by-cloudflare-parser-bug/>.
[CRIME] CVE, "CVE-2012-4929", <https://cve.mitre.org/cgi-bin/
cvename.cgi?name=cve-2012-4929>.
[GitHub.Tokens] [GitHub.Tokens]
"Security alert: Attack campaign involving stolen OAuth Hanley, M., "Security alert: Attack campaign involving
user tokens issued to two third-party integrators", stolen OAuth user tokens issued to two third-party
<https://github.blog/2022-04-15-security-alert-stolen- integrators", April 2022, <https://github.blog/2022-04-15-
oauth-user-tokens/>. security-alert-stolen-oauth-user-tokens/>.
[Heartbleed] [Heartbleed]
"CVE-2014-0160", <https://cve.mitre.org/cgi-bin/ "CVE-2014-0160", <https://cve.mitre.org/cgi-bin/
cvename.cgi?name=cve-2014-0160>. cvename.cgi?name=cve-2014-0160>.
[I-D.ietf-oauth-security-topics]
Lodderstedt, T., Bradley, J., Labunets, A., and D. Fett,
"OAuth 2.0 Security Best Current Practice", Work in
Progress, Internet-Draft, draft-ietf-oauth-security-
topics-22, 13 March 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-oauth-
security-topics-22>.
[I-D.ietf-oauth-token-binding]
Jones, M., Campbell, B., Bradley, J., and W. Denniss,
"OAuth 2.0 Token Binding", Work in Progress, Internet-
Draft, draft-ietf-oauth-token-binding-08, 19 October 2018,
<https://datatracker.ietf.org/doc/html/draft-ietf-oauth-
token-binding-08>.
[IANA.HTTP.AuthSchemes] [IANA.HTTP.AuthSchemes]
IANA, "Hypertext Transfer Protocol (HTTP) Authentication IANA, "Hypertext Transfer Protocol (HTTP) Authentication
Scheme Registry", Scheme Registry",
<https://www.iana.org/assignments/http-authschemes>. <https://www.iana.org/assignments/http-authschemes/>.
[IANA.HTTP.Fields] [IANA.HTTP.Fields]
IANA, "Hypertext Transfer Protocol (HTTP) Field Name IANA, "Hypertext Transfer Protocol (HTTP) Field Name
Registry", <https://www.iana.org/assignments/http-fields/ Registry",
http-fields.xhtml>. <https://www.iana.org/assignments/http-fields/>.
[IANA.JOSE.ALGS] [IANA.JOSE.ALGS]
IANA, "JSON Web Signature and Encryption Algorithms", IANA, "JSON Web Signature and Encryption Algorithms",
<https://www.iana.org/assignments/jose/jose.xhtml#web- <https://www.iana.org/assignments/jose/>.
signature-encryption-algorithms>.
[IANA.JWT] IANA, "JSON Web Token Claims", [IANA.JWT] IANA, "JSON Web Token Claims",
<https://www.iana.org/assignments/jwt>. <https://www.iana.org/assignments/jwt/>.
[IANA.MediaTypes] [IANA.MediaTypes]
IANA, "Media Types", IANA, "Media Types",
<https://www.iana.org/assignments/media-types>. <https://www.iana.org/assignments/media-types/>.
[IANA.OAuth.Params] [IANA.OAuth.Params]
IANA, "OAuth Parameters", IANA, "OAuth Parameters",
<https://www.iana.org/assignments/oauth-parameters>. <https://www.iana.org/assignments/oauth-parameters/>.
[OpenID.Core] [OpenID.Core]
Sakimura, N., Bradley, J., Jones, M.B., Medeiros, B.d., Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and
and C. Mortimore, "OpenID Connect Core 1.0", November C. Mortimore, "OpenID Connect Core 1.0 incorporating
2014, errata set 1", November 2014,
<https://openid.net/specs/openid-connect-core-1_0.html>. <https://openid.net/specs/openid-connect-core-1_0.html>.
[RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Two: Media Types", RFC 2046, Extensions (MIME) Part Two: Media Types", RFC 2046,
DOI 10.17487/RFC2046, November 1996, DOI 10.17487/RFC2046, November 1996,
<https://www.rfc-editor.org/info/rfc2046>. <https://www.rfc-editor.org/info/rfc2046>.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122, Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005, DOI 10.17487/RFC4122, July 2005,
skipping to change at page 43, line 20 skipping to change at line 1988
[RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke, [RFC9110] Fielding, R., Ed., Nottingham, M., Ed., and J. Reschke,
Ed., "HTTP Semantics", STD 97, RFC 9110, Ed., "HTTP Semantics", STD 97, RFC 9110,
DOI 10.17487/RFC9110, June 2022, DOI 10.17487/RFC9110, June 2022,
<https://www.rfc-editor.org/info/rfc9110>. <https://www.rfc-editor.org/info/rfc9110>.
[RFC9126] Lodderstedt, T., Campbell, B., Sakimura, N., Tonge, D., [RFC9126] Lodderstedt, T., Campbell, B., Sakimura, N., Tonge, D.,
and F. Skokan, "OAuth 2.0 Pushed Authorization Requests", and F. Skokan, "OAuth 2.0 Pushed Authorization Requests",
RFC 9126, DOI 10.17487/RFC9126, September 2021, RFC 9126, DOI 10.17487/RFC9126, September 2021,
<https://www.rfc-editor.org/info/rfc9126>. <https://www.rfc-editor.org/info/rfc9126>.
[W3C.CSP] West, M., "Content Security Policy Level 3", World Wide [SECURITY-TOPICS]
Web Consortium Working Draft WD-CSP3-20181015, 15 October Lodderstedt, T., Bradley, J., Labunets, A., and D. Fett,
2018, <https://www.w3.org/TR/2018/WD-CSP3-20181015/>. "OAuth 2.0 Security Best Current Practice", Work in
Progress, Internet-Draft, draft-ietf-oauth-security-
topics-23, 5 June 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-oauth-
security-topics-23>.
[TOKEN-BINDING]
Jones, M., Campbell, B., Bradley, J., and W. Denniss,
"OAuth 2.0 Token Binding", Work in Progress, Internet-
Draft, draft-ietf-oauth-token-binding-08, 19 October 2018,
<https://datatracker.ietf.org/doc/html/draft-ietf-oauth-
token-binding-08>.
[W3C.CSP] West, M., "Content Security Policy Level 3", W3C Working
Draft, July 2023, <https://www.w3.org/TR/CSP3/>.
[W3C.WebCryptoAPI] [W3C.WebCryptoAPI]
Watson, M., "Web Cryptography API", World Wide Web Watson, M., "Web Cryptography API", W3C Recommendation,
Consortium Recommendation REC-WebCryptoAPI-20170126, 26
January 2017, January 2017,
<https://www.w3.org/TR/2017/REC-WebCryptoAPI-20170126>. <https://www.w3.org/TR/2017/REC-WebCryptoAPI-20170126>.
[WHATWG.Fetch] [WHATWG.Fetch]
WHATWG, "Fetch Living Standard", May 2022, WHATWG, "Fetch Living Standard", July 2023,
<https://fetch.spec.whatwg.org/>. <https://fetch.spec.whatwg.org/>.
Appendix A. Acknowledgements Acknowledgements
We would like to thank Brock Allen, Annabelle Backman, Spencer We would like to thank Brock Allen, Annabelle Backman, Dominick
Balogh, Dominick Baier, Vittorio Bertocci, Jeff Corrigan, Domingos Baier, Spencer Balogh, Vittorio Bertocci, Jeff Corrigan, Domingos
Creado, Andrii Deinega, William Denniss, Vladimir Dzhuvinov, Mike Creado, Philippe De Ryck, Andrii Deinega, William Denniss, Vladimir
Engan, Nikos Fotiou, Mark Haine, Dick Hardt, Joseph Heenan, Bjorn Dzhuvinov, Mike Engan, Nikos Fotiou, Mark Haine, Dick Hardt, Joseph
Hjelm, Jacob Ideskog, Jared Jennings, Benjamin Kaduk, Pieter Heenan, Bjorn Hjelm, Jacob Ideskog, Jared Jennings, Benjamin Kaduk,
Kasselman, Neil Madden, Rohan Mahy, Karsten Meyer zu Selhausen, Pieter Kasselman, Neil Madden, Rohan Mahy, Karsten Meyer zu
Nicolas Mora, Steinar Noem, Mark Nottingham, Rob Otto, Aaron Parecki, Selhausen, Nicolas Mora, Steinar Noem, Mark Nottingham, Rob Otto,
Michael Peck, Roberto Polli, Paul Querna, Justin Richer, Joseph Aaron Parecki, Michael Peck, Roberto Polli, Paul Querna, Justin
Salowey, Rifaat Shekh-Yusef, Filip Skokan, Dmitry Telegin, Dave Richer, Joseph Salowey, Rifaat Shekh-Yusef, Filip Skokan, Dmitry
Tonge, Jim Willeke, Philippe De Ryck, and others (please let us know, Telegin, Dave Tonge, Jim Willeke, and others for their valuable
if you've been mistakenly omitted) for their valuable input, feedback input, feedback, and general support of this work.
and general support of this work.
This document originated from discussions at the 4th OAuth Security This document originated from discussions at the 4th OAuth Security
Workshop in Stuttgart, Germany. We thank the organizers of this Workshop in Stuttgart, Germany. We thank the organizers of this
workshop (Ralf Kusters, Guido Schmitz). workshop (Ralf Küsters and Guido Schmitz).
Appendix B. Document History
[[ To be removed from the final specification ]]
-16
* Per suggestion of the registry's designated expert, change
"resource error response" to "resource access error response" for
location of the two items in the "OAuth Extensions Error
Registration" section
-15
* Editorial updates from IESG review/ballot
* Mike Jones and Daniel Fett with new email/organization info
-14
* Add sec considerations sub-section about binding to client
identity
* Explicitly say that nonces must be unpredictable
* Change to a numbered list in 'Checking DPoP Proofs'
* Editorial adjustments
* Incorporated HTTP header field definition and RFC 8792 '\' line
wrapping suggestions by Mark Nottingham
-13
* Editorial updates/fixes
* Make sure RFC7519 is a normative reference
-12
* Updates from Roman Danyliw's AD review
* DPoP-Nonce now included in HTTP header field registration request
* Fixed section reference to URI Scheme-Based Normalization
* Attempt to better describe the rationale for SHA-256 only and
expectations for how hash algorithm agility would be achieved if
needed in the future
* Elaborate on the use of multiple WWW-Authenticate challenges by
protected resources
* Fix access token request examples that were missing a client_id
-11
* Updates addressing outstanding shepherd review comments per side
meeting discussions at IETF 114
* Added more explanation of the PAR considerations
* Added parenthetical remark "(such as ES256)" to Signature
Algorithms subsection
* Added more explanation for ath
* Added a reference to RFC8725 in mention of explicit JWT typing
-10
* Updates addressing some shepherd review comments
* Update HTTP references as RFCs 723x have been superseded by RFC
9110
* Editorial fixes
* Added some clarifications, etc. around nonce
* Added client considerations subsection
* Use bullets rather than numbers in Checking DPoP Proofs so as not
to imply specific order
* Added notes/reminders about browser-based client applications
using CORS needing access to response headers
* Added a JWT claims registry update request for "nonce" to (better)
allow for more general use in other contexts
-09
* Add note/reminder about browser-based client applications using
CORS needing access to response headers.
* Fixed typo
-08
* Lots of editorial updates from WGLC feedback
* Further clarify that either iat or nonce can be used alone in
validating the timeliness of the proof and somewhat de-emphasize
jti tracking
-07
* Registered the application/dpop+jwt media type.
* Editorial updates/clarifications based on review feedback.
* Added "(on the order of seconds or minutes)" to somewhat qualify
"relatively brief period" and "reasonably near future" and give a
general idea of expected timeframe without being overly
prescriptive.
* Added a step to Section 4.3 to reiterate that the jwk header
cannot have a private key.
-06
* Editorial updates and fixes
* Changed name of client metadata parameter to
dpop_bound_access_tokens
-05
* Added Authorization Code binding via the dpop_jkt parameter.
* Described the authorization code reuse attack and how dpop_jkt
mitigates it.
* Enhanced description of DPoP proof expiration checking.
* Described nonce storage requirements and how nonce mismatches and
missing nonces are self-correcting.
* Specified the use of the use_dpop_nonce error for missing and
mismatched nonce values.
* Specified that authorization servers use 400 (Bad Request) errors
to supply nonces and resource servers use 401 (Unauthorized)
errors to do so.
* Added a bit more about ath and pre-generated proofs to the
security considerations.
* Mentioned confirming the DPoP binding of the access token in the
list in Section 4.3.
* Added the always_uses_dpop client registration metadata parameter.
* Described the relationship between DPoP and Pushed Authorization
Requests (PAR).
* Updated references for drafts that are now RFCs.
-04
* Added the option for a server-provided nonce in the DPoP proof.
* Registered the invalid_dpop_proof and use_dpop_nonce error codes.
* Removed fictitious uses of realm from the examples, as they added
no value.
* State that if the introspection response has a token_type, it has
to be DPoP.
* Mention that RFC7235 allows multiple authentication schemes in
WWW-Authenticate with a 401.
* Editorial fixes.
-03
* Add an access token hash (ath) claim to the DPoP proof when used
in conjunction with the presentation of an access token for
protected resource access
* add Untrusted Code in the Client Context section to security
considerations
* Editorial updates and fixes
-02
* Lots of editorial updates and additions including expanding on the
objectives, better defining the key confirmation representations,
example updates and additions, better describing mixed bearer/dpop
token type deployments, clarify RT binding only being done for
public clients and why, more clearly allow for a bound RT but with
bearer AT, explain/justify the choice of SHA-256 for key binding,
and more
* Require that a protected resource supporting bearer and DPoP at
the same time must reject an access token received as bearer, if
that token is DPoP-bound
* Remove the case-insensitive qualification on the htm claim check
* Relax the jti tracking requirements a bit and qualify it by URI
-01
* Editorial updates
* Attempt to more formally define the DPoP Authorization header
scheme
* Define the 401/WWW-Authenticate challenge
* Added invalid_dpop_proof error code for DPoP errors in token
request
* Fixed up and added to the IANA section
* Added dpop_signing_alg_values_supported authorization server
metadata
* Moved the Acknowledgements into an Appendix and added a bunch of
names (best effort)
-00 [[ Working Group Draft ]]
* Working group draft
-04
* Update OAuth MTLS reference to RFC 8705
* Use the newish RFC v3 XML and HTML format
-03
* rework the text around uniqueness requirements on the jti claim in
the DPoP proof JWT
* make tokens a bit smaller by using htm, htu, and jkt rather than
http_method, http_uri, and jkt#S256 respectively
* more explicit recommendation to use mTLS if that is available
* added David Waite as co-author
* editorial updates
-02
* added normalization rules for URIs
* removed distinction between proof and binding
* "jwk" header again used instead of "cnf" claim in DPoP proof
* renamed "Bearer-DPoP" token type to "DPoP"
* removed ability for key rotation
* added security considerations on request integrity
* explicit advice on extending DPoP proofs to sign other parts of
the HTTP messages
* only use the jkt#S256 in ATs
* iat instead of exp in DPoP proof JWTs
* updated guidance on token_type evaluation
-01
* fixed inconsistencies
* moved binding and proof messages to headers instead of parameters
* extracted and unified definition of DPoP JWTs
* improved description
-00
* first draft
Authors' Addresses Authors' Addresses
Daniel Fett Daniel Fett
Authlete Authlete
Email: mail@danielfett.de Email: mail@danielfett.de
Brian Campbell Brian Campbell
Ping Identity Ping Identity
Email: bcampbell@pingidentity.com Email: bcampbell@pingidentity.com
John Bradley John Bradley
Yubico Yubico
Email: ve7jtb@ve7jtb.com Email: ve7jtb@ve7jtb.com
Torsten Lodderstedt Torsten Lodderstedt
yes.com Tuconic
Email: torsten@lodderstedt.net Email: torsten@lodderstedt.net
Michael Jones Michael Jones
independent Self-Issued Consulting
Email: michael_b_jones@hotmail.com Email: michael_b_jones@hotmail.com
URI: https://self-issued.info/ URI: https://self-issued.info/
David Waite David Waite
Ping Identity Ping Identity
Email: david@alkaline-solutions.com Email: david@alkaline-solutions.com
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