OAuth Working Group N. Sakimura Internet-Draft NAT.Consulting Intended status: Standards Track J. Bradley Expires: November 8, 2020 Yubico May 07, 2020 The OAuth 2.0 Authorization Framework: JWT Secured Authorization Request (JAR) draft-ietf-oauth-jwsreq-22 Abstract The authorization request in OAuth 2.0 described in RFC 6749 utilizes query parameter serialization, which means that Authorization Request parameters are encoded in the URI of the request and sent through user agents such as web browsers. While it is easy to implement, it means that (a) the communication through the user agents are not integrity protected and thus the parameters can be tainted, and (b) the source of the communication is not authenticated. Because of these weaknesses, several attacks to the protocol have now been put forward. This document introduces the ability to send request parameters in a JSON Web Token (JWT) instead, which allows the request to be signed with JSON Web Signature (JWS) and encrypted with JSON Web Encryption (JWE) so that the integrity, source authentication and confidentiality property of the Authorization Request is attained. The request can be sent by value or by reference. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on November 8, 2020. Sakimura & Bradley Expires November 8, 2020 [Page 1] Internet-Draft OAuth JAR May 2020 Copyright Notice Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Request Object . . . . . . . . . . . . . . . . . . . . . 6 2.2. Request Object URI . . . . . . . . . . . . . . . . . . . 6 3. Symbols and abbreviated terms . . . . . . . . . . . . . . . . 6 4. Request Object . . . . . . . . . . . . . . . . . . . . . . . 6 5. Authorization Request . . . . . . . . . . . . . . . . . . . . 9 5.1. Passing a Request Object by Value . . . . . . . . . . . . 9 5.2. Passing a Request Object by Reference . . . . . . . . . . 10 5.2.1. URI Referencing the Request Object . . . . . . . . . 11 5.2.2. Request using the "request_uri" Request Parameter . . 11 5.2.3. Authorization Server Fetches Request Object . . . . . 12 6. Validating JWT-Based Requests . . . . . . . . . . . . . . . . 13 6.1. Encrypted Request Object . . . . . . . . . . . . . . . . 13 6.2. JWS Signed Request Object . . . . . . . . . . . . . . . . 13 6.3. Request Parameter Assembly and Validation . . . . . . . . 13 7. Authorization Server Response . . . . . . . . . . . . . . . . 13 8. TLS Requirements . . . . . . . . . . . . . . . . . . . . . . 14 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . 14 9.1. OAuth Parameters Registration . . . . . . . . . . . . . . 14 9.2. Media Type Registration . . . . . . . . . . . . . . . . . 16 9.2.1. Registry Contents . . . . . . . . . . . . . . . . . . 16 10. Security Considerations . . . . . . . . . . . . . . . . . . . 16 10.1. Choice of Algorithms . . . . . . . . . . . . . . . . . . 17 10.2. Request Source Authentication . . . . . . . . . . . . . 17 10.3. Explicit Endpoints . . . . . . . . . . . . . . . . . . . 18 10.4. Risks Associated with request_uri . . . . . . . . . . . 18 10.4.1. DDoS Attack on the Authorization Server . . . . . . 18 10.4.2. Request URI Rewrite . . . . . . . . . . . . . . . . 19 11. TLS security considerations . . . . . . . . . . . . . . . . . 19 Sakimura & Bradley Expires November 8, 2020 [Page 2] Internet-Draft OAuth JAR May 2020 12. Privacy Considerations . . . . . . . . . . . . . . . . . . . 19 12.1. Collection limitation . . . . . . . . . . . . . . . . . 19 12.2. Disclosure Limitation . . . . . . . . . . . . . . . . . 20 12.2.1. Request Disclosure . . . . . . . . . . . . . . . . . 20 12.2.2. Tracking using Request Object URI . . . . . . . . . 21 13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 21 14. Revision History . . . . . . . . . . . . . . . . . . . . . . 21 15. References . . . . . . . . . . . . . . . . . . . . . . . . . 28 15.1. Normative References . . . . . . . . . . . . . . . . . . 28 15.2. Informative References . . . . . . . . . . . . . . . . . 30 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31 1. Introduction The Authorization Request in OAuth 2.0 [RFC6749] utilizes query parameter serialization and is typically sent through user agents such as web browsers. For example, the parameters "response_type", "client_id", "state", and "redirect_uri" are encoded in the URI of the request: GET /authorize?response_type=code&client_id=s6BhdRkqt3&state=xyz &redirect_uri=https%3A%2F%2Fclient%2Eexample%2Ecom%2Fcb HTTP/1.1 Host: server.example.com While it is easy to implement, the encoding in the URI does not allow application layer security to be used to provide confidentiality and integrity protection. While TLS is used to offer communication security between the Client and the user-agent as well as the user- agent and the Authorization Server, TLS sessions are terminated in the user-agent. In addition, TLS sessions may be terminated prematurely at some middlebox (such as a load balancer). As the result, the Authorization Request of [RFC6749] has shortcomings in that: (a) the communication through the user agents are not integrity protected and thus the parameters can be tainted (integrity protection failure) (b) the source of the communication is not authenticated (source authentication failure) (c) the communication through the user agents can be monitored (containment / confidentiality failure). Sakimura & Bradley Expires November 8, 2020 [Page 3] Internet-Draft OAuth JAR May 2020 Due to these inherent weaknesses, several attacks against the protocol, such as Redirection URI rewriting and Mix-up attack [FETT], have been identified. The use of application layer security mitigates these issues. The use of application layer security allows requests to be prepared by a third party so that a client application cannot request more permissions than previously agreed. This offers an additional degree of privacy protection. Furthermore, passing the request by reference allows the reduction of over-the-wire overhead. The JWT [RFC7519] encoding has been chosen because of (1) its close relationship with JSON, which is used as OAuth's response format (2) its developer friendliness due to its textual nature (3) its relative compactness compared to XML (4) its development status as a Proposed Standard, along with the associated signing and encryption methods [RFC7515] [RFC7516] (5) the relative ease of JWS and JWE compared to XML Signature and Encryption. The parameters "request" and "request_uri" are introduced as additional authorization request parameters for the OAuth 2.0 [RFC6749] flows. The "request" parameter is a JSON Web Token (JWT) [RFC7519] whose JWT Claims Set holds the JSON encoded OAuth 2.0 authorization request parameters. This JWT is integrity protected and source authenticated using JWS. The JWT [RFC7519] can be passed to the authorization endpoint by reference, in which case the parameter "request_uri" is used instead of the "request". Using JWT [RFC7519] as the request encoding instead of query parameters has several advantages: (a) (integrity protection) The request can be signed so that the integrity of the request can be checked. (b) (source authentication) The request can be signed so that the signer can be authenticated. Sakimura & Bradley Expires November 8, 2020 [Page 4] Internet-Draft OAuth JAR May 2020 (c) (confidentiality protection) The request can be encrypted so that end-to-end confidentiality can be provided even if the TLS connection is terminated at one point or another (including at and before user-agents). (d) (collection minimization) The request can be signed by a third party attesting that the authorization request is compliant with a certain policy. For example, a request can be pre-examined by a third party that all the personal data requested is strictly necessary to perform the process that the end-user asked for, and statically signed by that third party. The authorization server then examines the signature and shows the conformance status to the end-user, who would have some assurance as to the legitimacy of the request when authorizing it. There are a few cases that request by reference is useful such as: 1. When it is desirable to reduce the size of transmitted request. The use of application layer security increases the size of the request, particularly when public key cryptography is used. 2. When the client does not want to do the application level crypto. The Authorization Server may provide an endpoint to accept the Authorization Request through direct communication with the Client so that the Client is authenticated and the channel is TLS protected. This capability is in use by OpenID Connect [OpenID.Core]. 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here. 2. Terminology For the purposes of this specification, the following terms and definitions in addition to what is defined in OAuth 2.0 Framework [RFC6749], JSON Web Signature [RFC7515], and JSON Web Encryption [RFC7519] apply. Sakimura & Bradley Expires November 8, 2020 [Page 5] Internet-Draft OAuth JAR May 2020 2.1. Request Object JWT [RFC7519] that holds an OAuth 2.0 authorization request as JWT Claims Set 2.2. Request Object URI Absolute URI that references the set of parameters comprising an OAuth 2.0 authorization request. The contents of the resource referenced by the URI are a Request Object (Section 2.1), unless the URI was provided to the client by the same Authorization Server, in which case the content is an implementation detail at the discretion the Authorization Server. The former is to ensure interoperability in cases where the provider of the request_uri is a separate entity from the consumer, such as when a client provides a URI referencing a Request Object stored on the client's backend service and made accessible via HTTPS. In the latter case where the Authorization Server is both provider and consumer of the URI, such as when it offers an endpoint that provides a URI in exchange for a Request Object, this interoperability concern does not apply. 3. Symbols and abbreviated terms The following abbreviations are common to this specification. JSON Javascript Object Notation JWT JSON Web Token JWS JSON Web Signature JWE JSON Web Encryption URI Uniform Resource Identifier URL Uniform Resource Locator 4. Request Object A Request Object (Section 2.1) is used to provide authorization request parameters for an OAuth 2.0 authorization request. It MUST contain all the parameters (including extension parameters) used to process the OAuth 2.0 [RFC6749] authorization request except the "request" and "request_uri" parameters that are defined in this document. The parameters are represented as the JWT claims of the object. Parameter names and string values MUST be included as JSON strings. Since Request Objects are handled across domains and potentially outside of a closed ecosystem, per section 8.1 of Sakimura & Bradley Expires November 8, 2020 [Page 6] Internet-Draft OAuth JAR May 2020 [RFC8259], these JSON strings MUST be encoded using UTF-8 [RFC3629]. Numerical values MUST be included as JSON numbers. It MAY include any extension parameters. This JSON [RFC7159] object constitutes the JWT Claims Set defined in JWT [RFC7519]. The JWT Claims Set is then signed or signed and encrypted. To sign, JSON Web Signature (JWS) [RFC7515] is used. The result is a JWS signed JWT [RFC7519]. If signed, the Authorization Request Object SHOULD contain the Claims "iss" (issuer) and "aud" (audience) as members, with their semantics being the same as defined in the JWT [RFC7519] specification. The value of "aud" should be the value of the Authorization Server (AS) "issuer" as defined in RFC8414 [RFC8414]. To encrypt, JWE [RFC7516] is used. When both signature and encryption are being applied, the JWT MUST be signed then encrypted as advised in the section 11.2 of [RFC7519]. The result is a Nested JWT, as defined in [RFC7519]. The client determines the algorithms used to sign and encrypt request objects. This decision can be based on metadata the client registered via dynamic client registration [RFC7591] using the parameters "request_object_signing_alg", "request_object_encryption_alg", "request_object_encryption_enc" as defined in the the IANA "OAuth Dynamic Client Registration Metadata" registry [IANA.OAuth.Parameters] established by [RFC7591]. If the authorization server publishes its supported algorithms using Authorization Server Metadata [RFC8414], the algorithms used by the client must be contained in the list of algorithms published in the metadata data parameters "request_object_signing_alg_values_supported", "request_object_encryption_alg_values_supported", and "request_object_encryption_enc_values_supported" as defined in IANA "OAuth Authorization Server Metadata" registry [IANA.OAuth.Parameters] established by [RFC8414]. The Authorization Request Object MAY be sent by value as described in Section 5.1 or by reference as described in Section 5.2. "request" and "request_uri" parameters MUST NOT be included in Request Objects. A Request Object (Section 2.1) has the "mime-type" "application/ oauth.authz.req+jwt" Sakimura & Bradley Expires November 8, 2020 [Page 7] Internet-Draft OAuth JAR May 2020 The following is an example of the Claims in a Request Object before base64url encoding and signing. Note that it includes extension variables such as "nonce" and "max_age". { "iss": "s6BhdRkqt3", "aud": "https://server.example.com", "response_type": "code id_token", "client_id": "s6BhdRkqt3", "redirect_uri": "https://client.example.org/cb", "scope": "openid", "state": "af0ifjsldkj", "nonce": "n-0S6_WzA2Mj", "max_age": 86400 } Signing it with the "RS256" algorithm results in this Request Object value (with line wraps within values for display purposes only): eyJhbGciOiJSUzI1NiIsImtpZCI6ImsyYmRjIn0.ewogICAgImlzcyI6ICJzNkJoZF JrcXQzIiwKICAgICJhdWQiOiAiaHR0cHM6Ly9zZXJ2ZXIuZXhhbXBsZS5jb20iLAog ICAgInJlc3BvbnNlX3R5cGUiOiAiY29kZSBpZF90b2tlbiIsCiAgICAiY2xpZW50X2 lkIjogInM2QmhkUmtxdDMiLAogICAgInJlZGlyZWN0X3VyaSI6ICJodHRwczovL2Ns aWVudC5leGFtcGxlLm9yZy9jYiIsCiAgICAic2NvcGUiOiAib3BlbmlkIiwKICAgIC JzdGF0ZSI6ICJhZjBpZmpzbGRraiIsCiAgICAibm9uY2UiOiAibi0wUzZfV3pBMk1q IiwKICAgICJtYXhfYWdlIjogODY0MDAKfQ.Nsxa_18VUElVaPjqW_ToI1yrEJ67BgK b5xsuZRVqzGkfKrOIX7BCx0biSxYGmjK9KJPctH1OC0iQJwXu5YVY-vnW0_PLJb1C2 HG-ztVzcnKZC2gE4i0vgQcpkUOCpW3SEYXnyWnKzuKzqSb1wAZALo5f89B_p6QA6j6 JwBSRvdVsDPdulW8lKxGTbH82czCaQ50rLAg3EYLYaCb4ik4I1zGXE4fvim9FIMs8O CMmzwIB5S-ujFfzwFjoyuPEV4hJnoVUmXR_W9typPf846lGwA8h9G9oNTIuX8Ft2jf pnZdFmLg3_wr3Wa5q3a-lfbgF3S9H_8nN3j1i7tLR_5Nz-g The following RSA public key, represented in JWK format, can be used to validate the Request Object signature in this and subsequent Request Object examples (with line wraps within values for display purposes only): { "kty":"RSA", "kid":"k2bdc", "n":"x5RbkAZkmpRxia65qRQ1wwSMSxQUnS7gcpVTV_cdHmfmG2ltd2yabEO9XadD8 pJNZubINPpmgHh3J1aD9WRwS05ucmFq3CfFsluLt13_7oX5yDRSKX7poXmT_5 ko8k4NJZPMAO8fPToDTH7kHYbONSE2FYa5GZ60CUsFhSonI-dcMDJ0Ary9lxI w5k2z4TAdARVWcS7sD07VhlMMshrwsPHBQgTatlkxyIHXbYdtak8fqvNAwr7O lVEvM_Ipf5OfmdB8Sd-wjzaBsyP4VhJKoi_qdgSzpC694XZeYPq45Sw-q51iF UlcOlTCI7z6jltUtnR6ySn6XDGFnzH5Fe5ypw", "e":"AQAB" } Sakimura & Bradley Expires November 8, 2020 [Page 8] Internet-Draft OAuth JAR May 2020 5. Authorization Request The client constructs the authorization request URI by adding the following parameters to the query component of the authorization endpoint URI using the "application/x-www-form-urlencoded" format: request REQUIRED unless "request_uri" is specified. The Request Object (Section 2.1) that holds authorization request parameters stated in section 4 of OAuth 2.0 [RFC6749]. request_uri REQUIRED unless "request" is specified. The absolute URI as defined by RFC3986 [RFC3986] that is the Request Object URI (Section 2.2) referencing the authorization request parameters stated in section 4 of OAuth 2.0 [RFC6749]. client_id REQUIRED. OAuth 2.0 [RFC6749] "client_id". The value MUST match the "request" or "request_uri" Request Object's (Section 2.1) "client_id". The client directs the resource owner to the constructed URI using an HTTP redirection response, or by other means available to it via the user-agent. For example, the client directs the end user's user-agent to make the following HTTPS request: GET /authz?client_id=s6BhdRkqt3&request=eyJhbG..AlMGzw HTTP/1.1 Host: server.example.com The value for the request parameter is abbreviated for brevity. The authorization request object MUST be one of the following: (a) JWS signed (b) JWS signed and JWE encrypted The client MAY send the parameters included in the request object duplicated in the query parameters as well for the backward compatibility etc. However, the authorization server supporting this specification MUST only use the parameters included in the request object. 5.1. Passing a Request Object by Value The Client sends the Authorization Request as a Request Object to the Authorization Endpoint as the "request" parameter value. Sakimura & Bradley Expires November 8, 2020 [Page 9] Internet-Draft OAuth JAR May 2020 The following is an example of an Authorization Request using the "request" parameter (with line wraps within values for display purposes only): https://server.example.com/authorize?client_id=s6BhdRkqt3& request=eyJhbGciOiJSUzI1NiIsImtpZCI6ImsyYmRjIn0.ewogICAgImlzcyI6 ICJzNkJoZFJrcXQzIiwKICAgICJhdWQiOiAiaHR0cHM6Ly9zZXJ2ZXIuZXhhbXBs ZS5jb20iLAogICAgInJlc3BvbnNlX3R5cGUiOiAiY29kZSBpZF90b2tlbiIsCiAg ICAiY2xpZW50X2lkIjogInM2QmhkUmtxdDMiLAogICAgInJlZGlyZWN0X3VyaSI6 ICJodHRwczovL2NsaWVudC5leGFtcGxlLm9yZy9jYiIsCiAgICAic2NvcGUiOiAi b3BlbmlkIiwKICAgICJzdGF0ZSI6ICJhZjBpZmpzbGRraiIsCiAgICAibm9uY2Ui OiAibi0wUzZfV3pBMk1qIiwKICAgICJtYXhfYWdlIjogODY0MDAKfQ.Nsxa_18VU ElVaPjqW_ToI1yrEJ67BgKb5xsuZRVqzGkfKrOIX7BCx0biSxYGmjK9KJPctH1OC 0iQJwXu5YVY-vnW0_PLJb1C2HG-ztVzcnKZC2gE4i0vgQcpkUOCpW3SEYXnyWnKz uKzqSb1wAZALo5f89B_p6QA6j6JwBSRvdVsDPdulW8lKxGTbH82czCaQ50rLAg3E YLYaCb4ik4I1zGXE4fvim9FIMs8OCMmzwIB5S-ujFfzwFjoyuPEV4hJnoVUmXR_W 9typPf846lGwA8h9G9oNTIuX8Ft2jfpnZdFmLg3_wr3Wa5q3a-lfbgF3S9H_8nN3 j1i7tLR_5Nz-g 5.2. Passing a Request Object by Reference The "request_uri" Authorization Request parameter enables OAuth authorization requests to be passed by reference, rather than by value. This parameter is used identically to the "request" parameter, other than that the Request Object value is retrieved from the resource identified by the specified URI rather than passed by value. The entire Request URI MUST NOT exceed 512 ASCII characters. There are three reasons for this restriction. 1. Many phones in the market as of this writing still do not accept large payloads. The restriction is typically either 512 or 1024 ASCII characters. 2. The maximum URL length supported by older versions of Internet Explorer is 2083 ASCII characters. 3. On a slow connection such as 2G mobile connection, a large URL would cause the slow response and therefore the use of such is not advisable from the user experience point of view. The contents of the resource referenced by the URI MUST be a Request Object, unless the URI was provided to the client by the Authorization Server. The "request_uri" value MUST be either URN as defined in RFC8141 [RFC8141] or "https" URI, as defined in 2.7.2 of RFC7230 [RFC7230] . The "request_uri" value MUST be reachable by the Authorization Server. Sakimura & Bradley Expires November 8, 2020 [Page 10] Internet-Draft OAuth JAR May 2020 The following is an example of the contents of a Request Object resource that can be referenced by a "request_uri" (with line wraps within values for display purposes only): eyJhbGciOiJSUzI1NiIsImtpZCI6ImsyYmRjIn0.ewogICAgImlzcyI6ICJzNkJoZF JrcXQzIiwKICAgICJhdWQiOiAiaHR0cHM6Ly9zZXJ2ZXIuZXhhbXBsZS5jb20iLAog ICAgInJlc3BvbnNlX3R5cGUiOiAiY29kZSBpZF90b2tlbiIsCiAgICAiY2xpZW50X2 lkIjogInM2QmhkUmtxdDMiLAogICAgInJlZGlyZWN0X3VyaSI6ICJodHRwczovL2Ns aWVudC5leGFtcGxlLm9yZy9jYiIsCiAgICAic2NvcGUiOiAib3BlbmlkIiwKICAgIC JzdGF0ZSI6ICJhZjBpZmpzbGRraiIsCiAgICAibm9uY2UiOiAibi0wUzZfV3pBMk1q IiwKICAgICJtYXhfYWdlIjogODY0MDAKfQ.Nsxa_18VUElVaPjqW_ToI1yrEJ67BgK b5xsuZRVqzGkfKrOIX7BCx0biSxYGmjK9KJPctH1OC0iQJwXu5YVY-vnW0_PLJb1C2 HG-ztVzcnKZC2gE4i0vgQcpkUOCpW3SEYXnyWnKzuKzqSb1wAZALo5f89B_p6QA6j6 JwBSRvdVsDPdulW8lKxGTbH82czCaQ50rLAg3EYLYaCb4ik4I1zGXE4fvim9FIMs8O CMmzwIB5S-ujFfzwFjoyuPEV4hJnoVUmXR_W9typPf846lGwA8h9G9oNTIuX8Ft2jf pnZdFmLg3_wr3Wa5q3a-lfbgF3S9H_8nN3j1i7tLR_5Nz-g 5.2.1. URI Referencing the Request Object The Client stores the Request Object resource either locally or remotely at a URI the Authorization Server can access. Such facility may be provided by the authorization server or a third party. For example, the authorization server may provide a URL to which the client POSTs the request object and obtains the Request URI. This URI is the Request Object URI, "request_uri". It is possible for the Request Object to include values that are to be revealed only to the Authorization Server. As such, the "request_uri" MUST have appropriate entropy for its lifetime. For the guidance, refer to 5.1.4.2.2 of [RFC6819] and Good Practices for Capability URLs [CapURLs]. It is RECOMMENDED that it be removed after a reasonable timeout unless access control measures are taken. The following is an example of a Request Object URI value (with line wraps within values for display purposes only): https://tfp.example.org/request.jwt/ GkurKxf5T0Y-mnPFCHqWOMiZi4VS138cQO_V7PZHAdM 5.2.2. Request using the "request_uri" Request Parameter The Client sends the Authorization Request to the Authorization Endpoint. Sakimura & Bradley Expires November 8, 2020 [Page 11] Internet-Draft OAuth JAR May 2020 The following is an example of an Authorization Request using the "request_uri" parameter (with line wraps within values for display purposes only): https://server.example.com/authorize? response_type=code%20id_token &client_id=s6BhdRkqt3 &request_uri=https%3A%2F%2Ftfp.example.org%2Frequest.jwt %2FGkurKxf5T0Y-mnPFCHqWOMiZi4VS138cQO_V7PZHAdM 5.2.3. Authorization Server Fetches Request Object Upon receipt of the Request, the Authorization Server MUST send an HTTP "GET" request to the "request_uri" to retrieve the referenced Request Object, unless it is stored in a way so that it can retrieve it through other mechanism securely, and parse it to recreate the Authorization Request parameters. The following is an example of this fetch process: GET /request.jwt/GkurKxf5T0Y-mnPFCHqWOMiZi4VS138cQO_V7PZHAdM HTTP/1.1 Host: tfp.example.org The following is an example of the fetch response: HTTP/1.1 200 OK Date: Thu, 16 Feb 2017 23:52:39 GMT Server: Apache/2.2.22 (tfp.example.org) Content-type: application/oauth.authz.req+jwt Content-Length: 1250 Last-Modified: Wed, 15 Feb 2017 23:52:32 GMT eyJhbGciOiJSUzI1NiIsImtpZCI6ImsyYmRjIn0.ewogICAgImlzcyI6ICJzNkJoZF JrcXQzIiwKICAgICJhdWQiOiAiaHR0cHM6Ly9zZXJ2ZXIuZXhhbXBsZS5jb20iLAog ICAgInJlc3BvbnNlX3R5cGUiOiAiY29kZSBpZF90b2tlbiIsCiAgICAiY2xpZW50X2 lkIjogInM2QmhkUmtxdDMiLAogICAgInJlZGlyZWN0X3VyaSI6ICJodHRwczovL2Ns aWVudC5leGFtcGxlLm9yZy9jYiIsCiAgICAic2NvcGUiOiAib3BlbmlkIiwKICAgIC JzdGF0ZSI6ICJhZjBpZmpzbGRraiIsCiAgICAibm9uY2UiOiAibi0wUzZfV3pBMk1q IiwKICAgICJtYXhfYWdlIjogODY0MDAKfQ.Nsxa_18VUElVaPjqW_ToI1yrEJ67BgK b5xsuZRVqzGkfKrOIX7BCx0biSxYGmjK9KJPctH1OC0iQJwXu5YVY-vnW0_PLJb1C2 HG-ztVzcnKZC2gE4i0vgQcpkUOCpW3SEYXnyWnKzuKzqSb1wAZALo5f89B_p6QA6j6 JwBSRvdVsDPdulW8lKxGTbH82czCaQ50rLAg3EYLYaCb4ik4I1zGXE4fvim9FIMs8O CMmzwIB5S-ujFfzwFjoyuPEV4hJnoVUmXR_W9typPf846lGwA8h9G9oNTIuX8Ft2jf pnZdFmLg3_wr3Wa5q3a-lfbgF3S9H_8nN3j1i7tLR_5Nz-g Sakimura & Bradley Expires November 8, 2020 [Page 12] Internet-Draft OAuth JAR May 2020 6. Validating JWT-Based Requests 6.1. Encrypted Request Object If the request object is encrypted, the Authorization Server MUST decrypt the JWT in accordance with the JSON Web Encryption [RFC7516] specification. The result is a signed request object. If decryption fails, the Authorization Server MUST return an "invalid_request_object" error. 6.2. JWS Signed Request Object The Authorization Server MUST perform the signature validation of the JSON Web Signature [RFC7515] signed request object. For this, the "alg" Header Parameter in its JOSE Header MUST match the value of the pre-registered algorithm. The signature MUST be validated against the appropriate key for that "client_id" and algorithm. If signature validation fails, the Authorization Server MUST return an "invalid_request_object" error. 6.3. Request Parameter Assembly and Validation The Authorization Server MUST extract the set of Authorization Request parameters from the Request Object value. The Authorization Server MUST only use the parameters in the Request Object even if the same parameter is provided in the query parameter. The Authorization Server then validates the request as specified in OAuth 2.0 [RFC6749]. If the validation fails, then the Authorization Server MUST return an error as specified in OAuth 2.0 [RFC6749]. 7. Authorization Server Response Authorization Server Response is created and sent to the client as in Section 4 of OAuth 2.0 [RFC6749] . In addition, this document uses these additional error values: invalid_request_uri The "request_uri" in the Authorization Request returns an error or contains invalid data. invalid_request_object The request parameter contains an invalid Request Object. Sakimura & Bradley Expires November 8, 2020 [Page 13] Internet-Draft OAuth JAR May 2020 request_not_supported The Authorization Server does not support the use of the "request" parameter. request_uri_not_supported The Authorization Server does not support the use of the "request_uri" parameter. 8. TLS Requirements Client implementations supporting the Request Object URI method MUST support TLS following Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) [BCP195]. To protect against information disclosure and tampering, confidentiality protection MUST be applied using TLS with a cipher suite that provides confidentiality and integrity protection. HTTP clients MUST also verify the TLS server certificate, using DNS- ID [RFC6125], to avoid man-in-the-middle attacks. The rules and guidelines defined in [RFC6125] apply here, with the following considerations: o Support for DNS-ID identifier type (that is, the dNSName identity in the subjectAltName extension) is REQUIRED. Certification authorities which issue server certificates MUST support the DNS- ID identifier type, and the DNS-ID identifier type MUST be present in server certificates. o DNS names in server certificates MAY contain the wildcard character "*". o Clients MUST NOT use CN-ID identifiers; a CN field may be present in the server certificate's subject name, but MUST NOT be used for authentication within the rules described in [BCP195]. o SRV-ID and URI-ID as described in Section 6.5 of [RFC6125] MUST NOT be used for comparison. 9. IANA Considerations 9.1. OAuth Parameters Registration Since the request object is a JWT, the core JWT claims cannot be used for any purpose in the request object other than for what JWT dictates. Thus, they need to be registered to OAuth Parameter Registry to avoid future OAuth extensions using them with different meanings. Sakimura & Bradley Expires November 8, 2020 [Page 14] Internet-Draft OAuth JAR May 2020 This specification adds the following values to the "OAuth Parameters" registry established by [RFC6749]. o Claim Name: "iss" o Claim Description: Issuer of the JWT o Change Controller: IESG o Specification Document(s): Section 4.1.1 of [RFC7519] and this document. o Claim Name: "sub" o Claim Description: Subject of the JWT o Change Controller: IESG o Specification Document(s): Section 4.1.2 of [RFC7519] and this document. o Claim Name: "aud" o Claim Description: Audience of the JWT o Change Controller: IETF o Specification Document(s): Section 4.1.3 of [RFC7519] and this document. o Claim Name: "exp" o Claim Description: Expiry time of the JWT o Change Controller: IETF o Specification Document(s): Section 4.1.4 of [RFC7519] and this document. o Claim Name: "nbf" o Claim Description: Not Before - The time the JWT is not valid before o Change Controller: IETF o Specification Document(s): Section 4.1.5 of [RFC7519] and this document. o Claim Name: "iat" o Claim Description: The time the JWT was issued at. o Change Controller: IESG o Specification Document(s): Section 4.1.6 of [RFC7519] and this document. o Claim Name: "jti" o Claim Description: JWT Identifier o Change Controller: IESG o Specification Document(s): Section 4.1.7 of [RFC7519] and this document. Sakimura & Bradley Expires November 8, 2020 [Page 15] Internet-Draft OAuth JAR May 2020 9.2. Media Type Registration 9.2.1. Registry Contents This section registers the "application/oauth.authz.req+jwt" media type [RFC2046] in the "Media Types" registry [IANA.MediaTypes] in the manner described in [RFC6838], which can be used to indicate that the content is a JWT containing Request Object claims. o Type name: application o Subtype name: oauth.authz.req+jwt o Required parameters: n/a o Optional parameters: n/a o Encoding considerations: binary; A Request OBject is a JWT; JWT values are encoded as a series of base64url-encoded values (some of which may be the empty string) separated by period ('.') characters. o Security considerations: See Section 10 of [[ this specification ]] o Interoperability considerations: n/a o Published specification: Section 4 of [[ this specification ]] o Applications that use this media type: Applications that use Request Objects to make an OAuth 2.0 Authorization Request o Fragment identifier considerations: n/a o Additional information: Magic number(s): n/a File extension(s): n/a Macintosh file type code(s): n/a o Person & email address to contact for further information: Nat Sakimura, n-sakimura@nri.co.jp o Intended usage: COMMON o Restrictions on usage: none o Author: Nat Sakimura, n-sakimura@nri.co.jp o Change controller: IESG o Provisional registration? No 10. Security Considerations In addition to the all the security considerations discussed in OAuth 2.0 [RFC6819], the security considerations in [RFC7515], [RFC7516], [RFC7518], and [RFC8725] needs to be considered. Also, there are several academic papers such as [BASIN] that provide useful insight into the security properties of protocols like OAuth. In consideration of the above, this document advises taking the following security considerations into account. Sakimura & Bradley Expires November 8, 2020 [Page 16] Internet-Draft OAuth JAR May 2020 10.1. Choice of Algorithms When sending the authorization request object through "request" parameter, it MUST either be signed using JWS [RFC7515] or signed then encrypted using JWS [RFC7515] and JWE [RFC7516] respectively, with then considered appropriate algorithms. 10.2. Request Source Authentication The source of the Authorization Request MUST always be verified. There are several ways to do it in this specification. (a) Verifying the JWS Signature of the Request Object. (b) Verifying that the symmetric key for the JWE encryption is the correct one if the JWE is using symmetric encryption. (c) Verifying the TLS Server Identity of the Request Object URI. In this case, the Authorization Server MUST know out-of-band that the Client uses Request Object URI and only the Client is covered by the TLS certificate. In general, it is not a reliable method. (d) When Authorization Server is providing an endpoint that provides a Request Object URI in exchange for a Request Object, the Authorization Server MUST perform Client Authentication to accept the Request Object and bind the Client Identifier to the Request Object URI it is providing. Since Request Object URI can be replayed, the lifetime of the Request Object URI MUST be short and preferably one-time use. The entropy of the Request Object URI MUST be sufficiently large. The adequate shortness of the validity and the entropy of the Request Object URI depends on the risk calculation based on the value of the resource being protected. A general guidance for the validity time would be less than a minute and the Request Object URI is to include a cryptographic random value of 128bit or more at the time of the writing of this specification. (e) When a third party, such as a Trust Framework Provider(TFP), provides an endpoint that provides a Request Object URI in exchange for a Request Object. The same requirements as (b) and (c) above apply. In addition, the Authorization Server MUST know out-of-band that the Client utilizes the Trust Framework Operator and the Authorization Server MUST be a member of that trust framework so that it can trust the TFP. Sakimura & Bradley Expires November 8, 2020 [Page 17] Internet-Draft OAuth JAR May 2020 10.3. Explicit Endpoints Although this specification does not require them, research such as [BASIN] points out that it is a good practice to explicitly state the intended interaction endpoints and the message position in the sequence in a tamper evident manner so that the intent of the initiator is unambiguous. The following endpoints defined in [RFC6749], [RFC6750], and [RFC8414] are RECOMMENDED by this specification to use this practice : (a) Protected Resources ("protected_resources") (b) Authorization Endpoint ("authorization_endpoint") (c) Redirection URI ("redirect_uri") (d) Token Endpoint ("token_endpoint") Further, if dynamic discovery is used, then this practice also applies to the discovery related endpoints. In [RFC6749], while Redirection URI is included in the Authorization Request, others are not. As a result, the same applies to Authorization Request Object. The lack of the link among those endpoints are cited as the cause of Cross-Phase Attacks introduced in [FETT]. An extension specification should be created as a measure to address the risk. 10.4. Risks Associated with request_uri The introduction of "request_uri" introduces several attack possibilities. Consult the security considerations in Section 7 of RFC3986 [RFC3986] for more information regarding risks associated with URIs. 10.4.1. DDoS Attack on the Authorization Server A set of malicious client can launch a DoS attack to the authorization server by pointing the "request_uri" to a uri that returns extremely large content or extremely slow to respond. Under such an attack, the server may use up its resource and start failing. Similarly, a malicious client can specify the "request_uri" value that itself points to an authorization request URI that uses "request_uri" to cause the recursive lookup. Sakimura & Bradley Expires November 8, 2020 [Page 18] Internet-Draft OAuth JAR May 2020 To prevent such attack to succeed, the server should (a) check that the value of "request_uri" parameter does not point to an unexpected location, (b) check the content type of the response is "application/ oauth.authz.req+jwt" (c) implement a time-out for obtaining the content of "request_uri", and (d) not perform recursive GET on the "request_uri". 10.4.2. Request URI Rewrite The value of "request_uri" is not signed thus it can be tampered by Man-in-the-browser attacker. Several attack possibilities rise because of this, e.g., (a) attacker may create another file that the rewritten URI points to making it possible to request extra scope (b) attacker launches a DoS attack to a victim site by setting the value of "request_uri" to be that of the victim. To prevent such attack to succeed, the server should (a) check that the value of "request_uri" parameter does not point to an unexpected location, (b) check the content type of the response is "application/ oauth.authz.req+jwt" (c) implement a time-out for obtaining the content of "request_uri". 11. TLS security considerations Current security considerations can be found in Recommendations for Secure Use of TLS and DTLS [BCP195]. This supersedes the TLS version recommendations in OAuth 2.0 [RFC6749]. 12. Privacy Considerations When the Client is being granted access to a protected resource containing personal data, both the Client and the Authorization Server need to adhere to Privacy Principles. RFC 6973 Privacy Considerations for Internet Protocols [RFC6973] gives excellent guidance on the enhancement of protocol design and implementation. The provision listed in it should be followed. Most of the provision would apply to The OAuth 2.0 Authorization Framework [RFC6749] and The OAuth 2.0 Authorization Framework: Bearer Token Usage [RFC6750] and are not specific to this specification. In what follows, only the specific provisions to this specification are noted. 12.1. Collection limitation When the Client is being granted access to a protected resource containing personal data, the Client SHOULD limit the collection of Sakimura & Bradley Expires November 8, 2020 [Page 19] Internet-Draft OAuth JAR May 2020 personal data to that which is within the bounds of applicable law and strictly necessary for the specified purpose(s). It is often hard for the user to find out if the personal data asked for is strictly necessary. A Trust Framework Provider can help the user by examining the Client request and comparing to the proposed processing by the Client and certifying the request. After the certification, the Client, when making an Authorization Request, can submit Authorization Request to the Trust Framework Provider to obtain the Request Object URI. This process is two steps: (1) (Certification Process) The TFP examines the business process of the client and determines what claims they need: This is the certification process. Once the client is certified, then they are issued a client credential to authenticate against to push request objects to the TFP to get the "request_uri". (2) (Translation Process) The client uses the client credential that it got to push the request object to the TFP to get the "request_uri". Upon receiving such Request Object URI in the Authorization Request, the Authorization Server first verifies that the authority portion of the Request Object URI is a legitimate one for the Trust Framework Provider. Then, the Authorization Server issues HTTP GET request to the Request Object URI. Upon connecting, the Authorization Server MUST verify the server identity represented in the TLS certificate is legitimate for the Request Object URI. Then, the Authorization Server can obtain the Request Object, which includes the "client_id" representing the Client. The Consent screen MUST indicate the Client and SHOULD indicate that the request has been vetted by the Trust Framework Operator for the adherence to the Collection Limitation principle. 12.2. Disclosure Limitation 12.2.1. Request Disclosure This specification allows extension parameters. These may include potentially sensitive information. Since URI query parameter may leak through various means but most notably through referrer and browser history, if the authorization request contains a potentially sensitive parameter, the Client SHOULD JWE [RFC7516] encrypt the request object. Where Request Object URI method is being used, if the request object contains personally identifiable or sensitive information, the Sakimura & Bradley Expires November 8, 2020 [Page 20] Internet-Draft OAuth JAR May 2020 "request_uri" SHOULD be used only once, have a short validity period, and MUST have large enough entropy deemed necessary with applicable security policy unless the Request Object itself is JWE [RFC7516] Encrypted. The adequate shortness of the validity and the entropy of the Request Object URI depends on the risk calculation based on the value of the resource being protected. A general guidance for the validity time would be less than a minute and the Request Object URI is to include a cryptographic random value of 128bit or more at the time of the writing of this specification. 12.2.2. Tracking using Request Object URI Even if the protected resource does not include a personally identifiable information, it is sometimes possible to identify the user through the Request Object URI if persistent static per-user Request Object URIs are used. A third party may observe it through browser history etc. and start correlating the user's activity using it. In a way, it is a data disclosure as well and should be avoided. Therefore, per-user Request Object URI should be avoided. 13. Acknowledgements The following people contributed to the creation of this document in the OAuth WG. (Affiliations at the time of the contribution are used.) Sergey Beryozkin, Brian Campbell (Ping Identity), Vladimir Dzhuvinov (Connect2id), Michael B. Jones (Microsoft), Torsten Lodderstedt (yes.com) Jim Manico, Axel Nenker(Deutsche Telecom), Hannes Tschofenig (ARM), Ben Campbell, Dirk Balfanz (Google), James H. Manger (Telstra), John Panzer (Google), David Recordon (Facebook), Marius Scurtescu (Google), Luke Shepard (Facebook), Annabelle Backman (Amazon) Kathleen Moriarty (as AD), and Steve Kent (as SECDIR). The following people contributed to creating this document through the OpenID Connect Core 1.0 [OpenID.Core]. Brian Campbell (Ping Identity), George Fletcher (AOL), Ryo Itou (Mixi), Edmund Jay (Illumila), Michael B. Jones (Microsoft), Breno de Medeiros (Google), Hideki Nara (TACT), Justin Richer (MITRE). 14. Revision History Note to the RFC Editor: Please remove this section from the final RFC. -20 Sakimura & Bradley Expires November 8, 2020 [Page 21] Internet-Draft OAuth JAR May 2020 o BK comments o Section 3 Removed WAP o Section 4. Clarified authorization request object parameters, removed extension parameters from examples o Section 4. Specifies application/oauth.authz.req+jwt as mime-type fore request objects o Section 5.2.1 Added reference to Capability URLs o Section 5.2.3. Added entrophy fragment to example request o Section 8. Replaced "subjectAltName dnsName" with "DNS-ID" o Section 9. Registers authorization request parameters in JWT Claims Registry. o Section 9. Registers application/oauth.authz.req in IANA mime- types registry o Section 10.1. Clarified encypted request objects are "signed then encrypted" to maintain consistency o Section 10.2. Clarifies trust between AS and TFP o Section 10.3. Clarified endpoints subject to the practice o Section 10.4 Replaced "redirect_uri" to "request_uri" o Section 10.4. Added reference to RFC 3986 for risks o Section 10.4.1.d Deleted "do" to maintain grammar flow o Section 10.4.1, 10.4.2 Replaced "application/jose" to "application/jwt" o Section 12.1. Extended description for submitting authorization request to TFP to obtain request objec o Section 12.2.2. Replaced per-user Request Object URI with static per-user Request URIs o Section 13. Combined OAuth WG contributors together o Section Whole doc Replaced application/jwt with application/ oauth.authz.req+jwt Sakimura & Bradley Expires November 8, 2020 [Page 22] Internet-Draft OAuth JAR May 2020 -19 o AD comments o Section 5.2.1. s/Requiest URI/Request URI/ o Section 8 s/[BCP195] ./[BCP195]./ o Section 10.3. s/sited/cited/ o Section 11. Typo. s/Curent/Current/ -17 o #78 Typos in content-type -16 o Treated remaining Ben Campbell comments. -15 o Removed further duplication -14 o #71 Reiterate dynamic params are included. o #70 Made clear that AS must return error. o #69 Inconsistency of the need to sign. o Fixed Mimetype. o #67 Incosistence in requiring HTTPS in request uri. o #66 Dropped ISO 29100 reference. o #25 Removed Encrypt only option. o #59 Same with #25. -13 o add TLS Security Consideration section o replace RFC7525 reference with BCP195 Sakimura & Bradley Expires November 8, 2020 [Page 23] Internet-Draft OAuth JAR May 2020 o moved front tag in FETT reference to fix XML structure o changes reference from SoK to FETT -12 o fixes #62 - Alexey Melnikov Discuss o fixes #48 - OPSDIR Review : General - delete semicolors after list items o fixes #58 - DP Comments for the Last Call o fixes #57 - GENART - Remove "non-normative ... " from examples. o fixes #45 - OPSDIR Review : Introduction - are attacks discovered or already opened o fixes #49 - OPSDIR Review : Introduction - Inconsistent colons after initial sentence of list items. o fixes #53 - OPSDIR Review : 6.2 JWS Signed Request Object - Clarify JOSE Header o fixes #42 - OPSDIR Review : Introduction - readability of 'and' is confusing o fixes #50 - OPSDIR Review : Section 4 Request Object - Clarify 'signed, encrypted, or signed and encrypted' o fixes #39 - OPSDIR Review : Abstract - Explain/Clarify JWS and JWE o fixed #50 - OPSDIR Review : Section 4 Request Object - Clarify 'signed, encrypted, or signed and encrypted' o fixes #43 - OPSDIR Review : Introduction - 'properties' sounds awkward and are not exactly 'properties' o fixes #56 - OPSDIR Review : 12 Acknowledgements - 'contribution is' => 'contribution are' o fixes #55 - OPSDIR Review : 11.2.2 Privacy Considerations - ' It is in a way' => 'In a way, it is' o fixes #54 - OPSDIR Review : 11 Privacy Considerations - 'and not specific' => 'and are not specific' Sakimura & Bradley Expires November 8, 2020 [Page 24] Internet-Draft OAuth JAR May 2020 o fixes #51 - OPSDIR Review : Section 4 Request Object - 'It is fine' => 'It is recommended' o fixes #47 - OPSDIR Review : Introduction - 'over- the- wire' => 'over-the-wire' o fixes #46 - OPSDIR Review : Introduction - 'It allows' => 'The use of application security' for o fixes #44 - OPSDIR Review : Introduction - 'has' => 'have' o fixes #41 - OPSDIR Review : Introduction - missing 'is' before 'typically sent' o fixes #38 - OPSDIR Review : Section 11 - Delete 'freely accessible' regarding ISO 29100 -11 o s/bing/being/ o Added history for -10 -10 o #20: KM1 -- some wording that is awkward in the TLS section. o #21: KM2 - the additional attacks against OAuth 2.0 should also have a pointer o #22: KM3 -- Nit: in the first line of 10.4: o #23: KM4 -- Mention RFC6973 in Section 11 in addition to ISO 29100 o #24: SECDIR review: Section 4 -- Confusing requirements for sign+encrypt o #25: SECDIR review: Section 6 -- authentication and integrity need not be provided if the requestor encrypts the token? o #26: SECDIR Review: Section 10 -- why no reference for JWS algorithms? o #27: SECDIR Review: Section 10.2 - how to do the agreement between client and server "a priori"? o #28: SECDIR Review: Section 10.3 - Indication on "large entropy" and "short lifetime" should be indicated Sakimura & Bradley Expires November 8, 2020 [Page 25] Internet-Draft OAuth JAR May 2020 o #29: SECDIR Review: Section 10.3 - Typo o #30: SECDIR Review: Section 10.4 - typos and missing articles o #31: SECDIR Review: Section 10.4 - Clearer statement on the lack of endpoint identifiers needed o #32: SECDIR Review: Section 11 - ISO29100 needs to be moved to normative reference o #33: SECDIR Review: Section 11 - Better English and Entropy language needed o #34: Section 4: Typo o #35: More Acknowledgment o #36: DP - More precise qualification on Encryption needed. -09 o Minor Editorial Nits. o Section 10.4 added. o Explicit reference to Security consideration (10.2) added in section 5 and section 5.2. o , (add yourself) removed from the acknowledgment. -08 o Applied changes proposed by Hannes on 2016-06-29 on IETF OAuth list recorded as https://bitbucket.org/Nat/oauth-jwsreq/ issues/12/. o TLS requirements added. o Security Consideration reinforced. o Privacy Consideration added. o Introduction improved. -07 o Changed the abbrev to OAuth JAR from oauth-jar. Sakimura & Bradley Expires November 8, 2020 [Page 26] Internet-Draft OAuth JAR May 2020 o Clarified sig and enc methods. o Better English. o Removed claims from one of the example. o Re-worded the URI construction. o Changed the example to use request instead of request_uri. o Clarified that Request Object parameters take precedence regardless of request or request_uri parameters were used. o Generalized the language in 4.2.1 to convey the intent more clearly. o Changed "Server" to "Authorization Server" as a clarification. o Stopped talking about request_object_signing_alg. o IANA considerations now reflect the current status. o Added Brian Campbell to the contributors list. Made the lists alphabetic order based on the last names. Clarified that the affiliation is at the time of the contribution. o Added "older versions of " to the reference to IE uri length limitations. o Stopped talking about signed or unsigned JWS etc. o 1.Introduction improved. -06 o Added explanation on the 512 chars URL restriction. o Updated Acknowledgements. -05 o More alignment with OpenID Connect. -04 o Fixed typos in examples. (request_url -> request_uri, cliend_id -> client_id) Sakimura & Bradley Expires November 8, 2020 [Page 27] Internet-Draft OAuth JAR May 2020 o Aligned the error messages with the OAuth IANA registry. o Added another rationale for having request object. -03 o Fixed the non-normative description about the advantage of static signature. o Changed the requirement for the parameter values in the request itself and the request object from 'MUST MATCH" to 'Req Obj takes precedence. -02 o Now that they are RFCs, replaced JWS, JWE, etc. with RFC numbers. -01 o Copy Edits. 15. References 15.1. Normative References [BCP195] Sheffer, Y., Holz, R., and P. Saint-Andre, "Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", BCP 195, RFC 7525, May 2015. [IANA.MediaTypes] IANA, "Media Types", . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November 2003, . [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, January 2005, . Sakimura & Bradley Expires November 8, 2020 [Page 28] Internet-Draft OAuth JAR May 2020 [RFC6125] Saint-Andre, P. and J. Hodges, "Representation and Verification of Domain-Based Application Service Identity within Internet Public Key Infrastructure Using X.509 (PKIX) Certificates in the Context of Transport Layer Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March 2011, . [RFC6749] Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, October 2012, . [RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization Framework: Bearer Token Usage", RFC 6750, DOI 10.17487/RFC6750, October 2012, . [RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March 2014, . [RFC7230] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer Protocol (HTTP/1.1): Message Syntax and Routing", RFC 7230, DOI 10.17487/RFC7230, June 2014, . [RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May 2015, . [RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)", RFC 7516, DOI 10.17487/RFC7516, May 2015, . [RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518, DOI 10.17487/RFC7518, May 2015, . [RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015, . [RFC7636] Sakimura, N., Ed., Bradley, J., and N. Agarwal, "Proof Key for Code Exchange by OAuth Public Clients", RFC 7636, DOI 10.17487/RFC7636, September 2015, . Sakimura & Bradley Expires November 8, 2020 [Page 29] Internet-Draft OAuth JAR May 2020 [RFC8141] Saint-Andre, P. and J. Klensin, "Uniform Resource Names (URNs)", RFC 8141, DOI 10.17487/RFC8141, April 2017, . [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, May 2017, . [RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, December 2017, . [RFC8414] Jones, M., Sakimura, N., and J. Bradley, "OAuth 2.0 Authorization Server Metadata", RFC 8414, DOI 10.17487/RFC8414, June 2018, . [RFC8485] Richer, J., Ed. and L. Johansson, "Vectors of Trust", RFC 8485, DOI 10.17487/RFC8485, October 2018, . 15.2. Informative References [BASIN] Basin, D., Cremers, C., and S. Meier, "Provably Repairing the ISO/IEC 9798 Standard for Entity Authentication", Journal of Computer Security - Security and Trust Principles Volume 21 Issue 6, Pages 817-846, November 2013, . [CapURLs] Tennison, J., "Good Practices for Capability URLs", W3C Working Draft, February 2014, . [FETT] Fett, D., Kusters, R., and G. Schmitz, "A Comprehensive Formal Security Analysis of OAuth 2.0", CCS '16 Proceedings of the 2016 ACM SIGSAC Conference on Computer and Communications Security Pages 1204-1215 , October 2016, . [IANA.OAuth.Parameters] IANA, "OAuth Parameters", . Sakimura & Bradley Expires November 8, 2020 [Page 30] Internet-Draft OAuth JAR May 2020 [OpenID.Core] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, "OpenID Connect Core 1.0", OpenID Foundation Standards, February 2014, . [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, DOI 10.17487/RFC2046, November 1996, . [RFC6819] Lodderstedt, T., Ed., McGloin, M., and P. Hunt, "OAuth 2.0 Threat Model and Security Considerations", RFC 6819, DOI 10.17487/RFC6819, January 2013, . [RFC6838] Freed, N., Klensin, J., and T. Hansen, "Media Type Specifications and Registration Procedures", BCP 13, RFC 6838, DOI 10.17487/RFC6838, January 2013, . [RFC6973] Cooper, A., Tschofenig, H., Aboba, B., Peterson, J., Morris, J., Hansen, M., and R. Smith, "Privacy Considerations for Internet Protocols", RFC 6973, DOI 10.17487/RFC6973, July 2013, . [RFC7591] Richer, J., Ed., Jones, M., Bradley, J., Machulak, M., and P. Hunt, "OAuth 2.0 Dynamic Client Registration Protocol", RFC 7591, DOI 10.17487/RFC7591, July 2015, . [RFC8725] Sheffer, Y., Hardt, D., and M. Jones, "JSON Web Token Best Current Practices", BCP 225, RFC 8725, DOI 10.17487/RFC8725, February 2020, . Authors' Addresses Nat Sakimura NAT.Consulting 2-22-17 Naka Kunitachi, Tokyo 186-0004 Japan Phone: +81-42-580-7401 Email: nat@nat.consulting URI: http://nat.sakimura.org/ Sakimura & Bradley Expires November 8, 2020 [Page 31] Internet-Draft OAuth JAR May 2020 John Bradley Yubico Casilla 177, Sucursal Talagante Talagante, RM Chile Phone: +1.202.630.5272 Email: ve7jtb@ve7jtb.com URI: http://www.thread-safe.com/ Sakimura & Bradley Expires November 8, 2020 [Page 32]