TOC 
DraftN. Sakimura
 NRI
 J. Bradley
 Ping Identity
 M. Jones
 Microsoft
 E. Jay
 Illumila
 August 18, 2014


OpenID Connect Discovery 1.0 - draft 24 incorporating errata set 1

Abstract

OpenID Connect 1.0 is a simple identity layer on top of the OAuth 2.0 protocol. It enables Clients to verify the identity of the End-User based on the authentication performed by an Authorization Server, as well as to obtain basic profile information about the End-User in an interoperable and REST-like manner.

This specification defines a mechanism for an OpenID Connect Relying Party to discover the End-User's OpenID Provider and obtain information needed to interact with it, including its OAuth 2.0 endpoint locations.



Table of Contents

1.  Introduction
    1.1.  Requirements Notation and Conventions
    1.2.  Terminology
2.  OpenID Provider Issuer Discovery
    2.1.  Identifier Normalization
        2.1.1.  User Input Identifier Types
        2.1.2.  Normalization Steps
    2.2.  Non-Normative Examples
        2.2.1.  User Input using E-Mail Address Syntax
        2.2.2.  User Input using URL Syntax
        2.2.3.  User Input using Hostname and Port Syntax
        2.2.4.  User Input using "acct" URI Syntax
3.  OpenID Provider Metadata
4.  Obtaining OpenID Provider Configuration Information
    4.1.  OpenID Provider Configuration Request
    4.2.  OpenID Provider Configuration Response
    4.3.  OpenID Provider Configuration Validation
5.  String Operations
6.  Implementation Considerations
    6.1.  Pre-Final IETF Specifications
7.  Security Considerations
    7.1.  TLS Requirements
    7.2.  Impersonation Attacks
8.  IANA Considerations
    8.1.  Well-Known URI Registry
        8.1.1.  Registry Contents
9.  References
    9.1.  Normative References
    9.2.  Informative References
Appendix A.  Acknowledgements
Appendix B.  Notices
Appendix C.  Document History
§  Authors' Addresses




 TOC 

1.  Introduction

OpenID Connect 1.0 is a simple identity layer on top of the OAuth 2.0 [RFC6749] (Hardt, D., “The OAuth 2.0 Authorization Framework,” October 2012.) protocol. It enables Clients to verify the identity of the End-User based on the authentication performed by an Authorization Server, as well as to obtain basic profile information about the End-User in an interoperable and REST-like manner.

In order for an OpenID Connect Relying Party to utilize OpenID Connect services for an End-User, the RP needs to know where the OpenID Provider is. OpenID Connect uses WebFinger (Jones, P., Salgueiro, G., Jones, M., and J. Smarr, “WebFinger,” September 2013.) [RFC7033] to locate the OpenID Provider for an End-User. This process is described in Section 2 (OpenID Provider Issuer Discovery).

Once the OpenID Provider has been identified, the configuration information for that OP is retrieved from a well-known location as a JSON document, including its OAuth 2.0 endpoint locations. This process is described in Section 4 (Obtaining OpenID Provider Configuration Information).



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1.1.  Requirements Notation and Conventions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 (Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” March 1997.) [RFC2119].

In the .txt version of this document, values are quoted to indicate that they are to be taken literally. When using these values in protocol messages, the quotes MUST NOT be used as part of the value. In the HTML version of this document, values to be taken literally are indicated by the use of this fixed-width font.

All uses of JSON Web Signature (JWS) (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” July 2014.) [JWS] and JSON Web Encryption (JWE) (Jones, M., Rescorla, E., and J. Hildebrand, “JSON Web Encryption (JWE),” July 2014.) [JWE] data structures in this specification utilize the JWS Compact Serialization or the JWE Compact Serialization; the JWS JSON Serialization and the JWE JSON Serialization are not used.



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1.2.  Terminology

This specification uses the terms "Access Token", "Authorization Code", "Authorization Endpoint", "Authorization Grant", "Authorization Server", "Client", "Client Authentication", "Client Identifier", "Client Secret", "Grant Type", "Protected Resource", "Redirection URI", "Refresh Token", "Resource Owner", "Resource Server", "Response Type", and "Token Endpoint" defined by OAuth 2.0 (Hardt, D., “The OAuth 2.0 Authorization Framework,” October 2012.) [RFC6749], the terms "Claim Name", "Claim Value", and "JSON Web Token (JWT)" defined by JSON Web Token (JWT) (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” July 2014.) [JWT], and the terms defined by OpenID Connect Core 1.0 (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.) [OpenID.Core] and OAuth 2.0 Multiple Response Type Encoding Practices (de Medeiros, B., Ed., Scurtescu, M., Tarjan, P., and M. Jones, “OAuth 2.0 Multiple Response Type Encoding Practices,” February 2014.) [OAuth.Responses].

This specification also defines the following terms:

Resource
Entity that is the target of a request in WebFinger.
Host
Server where a WebFinger service is hosted.
Identifier
Value that uniquely characterizes an Entity in a specific context.
NOTE: this document defines various kinds of Identifiers, designed for use in different contexts. Examples include URLs using the https scheme and e-mail addresses.

IMPORTANT NOTE TO READERS: The terminology definitions in this section are a normative portion of this specification, imposing requirements upon implementations. All the capitalized words in the text of this specification, such as "Identifier", reference these defined terms. Whenever the reader encounters them, their definitions found in this section must be followed.



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2.  OpenID Provider Issuer Discovery

OpenID Provider Issuer discovery is the process of determining the location of the OpenID Provider.

Issuer discovery is OPTIONAL; if a Relying Party knows the OP's Issuer location through an out-of-band mechanism, it can skip this step and proceed to Section 4 (Obtaining OpenID Provider Configuration Information).

Issuer discovery requires the following information to make a discovery request:

resource
Identifier for the target End-User that is the subject of the discovery request.
host
Server where a WebFinger service is hosted.
rel
URI identifying the type of service whose location is being requested.

OpenID Connect uses the following discoverable rel value in WebFinger (Jones, P., Salgueiro, G., Jones, M., and J. Smarr, “WebFinger,” September 2013.) [RFC7033]:

Rel TypeURI
OpenID Connect Issuer http://openid.net/specs/connect/1.0/issuer

To start discovery of OpenID endpoints, the End-User supplies an Identifier to the Relying Party. The RP applies normalization rules to the Identifier to determine the Resource and Host. Then it makes an HTTP GET request to the Host's WebFinger (Jones, P., Salgueiro, G., Jones, M., and J. Smarr, “WebFinger,” September 2013.) [RFC7033] endpoint with the resource and rel parameters to obtain the location of the requested service. All WebFinger communication MUST utilize TLS in the manner described in Section 7.1 (TLS Requirements).

The Issuer location MUST be returned in the WebFinger response as the value of the href member of a links array element with rel member value http://openid.net/specs/connect/1.0/issuer. (Per Section 7 of WebFinger (Jones, P., Salgueiro, G., Jones, M., and J. Smarr, “WebFinger,” September 2013.) [RFC7033], obtaining the WebFinger response may first involve following some redirects.)

The returned Issuer location MUST be a URI RFC 3986 (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.) [RFC3986] with a scheme component that MUST be https, a host component, and optionally, port and path components and no query or fragment components. Note that since the Host and Resource values determined from the user input Identifier, as described in Section 2.1 (Identifier Normalization), are used as input to a WebFinger request, which can return an Issuer value using a completely different scheme, host, port, and path, no relationship can be assumed between the user input Identifier string and the resulting Issuer location.



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2.1.  Identifier Normalization

The purpose of Identifier normalization is to determine normalized Resource and Host values from the user input Identifier. These are then used as WebFinger request parameters to discover the Issuer location.

The user input Identifier SHOULD be a URL or URI relative reference defined in RFC 3986 (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.) [RFC3986]. The user input Identifier MUST include the authority component.

NOTE: A URI relative reference includes a string that looks like an e-mail address in the form of userinfo@host. This is a valid authority component of a URI but excludes various possible extra strings allowed in addr-spec syntax of RFC 5322 (Resnick, P., Ed., “Internet Message Format,” October 2008.) [RFC5322].

The Identifier normalization rules MAY be extended by additional specifications to enable other identifier types such as telephone numbers or XRIs (Reed, D. and D. McAlpin, “Extensible Resource Identifier (XRI) Syntax V2.0,” November 2005.) [XRI_Syntax_2.0] to also be used.



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2.1.1.  User Input Identifier Types

A user input Identifier can be categorized into the following types, which require different normalization processes:

  1. User input Identifiers starting with the XRI (Reed, D. and D. McAlpin, “Extensible Resource Identifier (XRI) Syntax V2.0,” November 2005.) [XRI_Syntax_2.0] global context symbols ('=','@', and '!') are RESERVED. Processing of these identifiers is out of scope for this specification.
  2. All other user input Identifiers MUST be treated as a URI in one of the forms scheme "://" authority path-abempty [ "?" query ] [ "#" fragment ] or authority path-abempty [ "?" query ] [ "#" fragment ] or scheme ":" path-rootless, per RFC 3986 (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.) [RFC3986].

NOTE: The user input Identifier MAY be in the form of userinfo@host. For the End-User, this would normally be perceived as being an e-mail address. However, it is also a valid userpart "@" host section of an acct URI [I‑D.ietf‑appsawg‑acct‑uri] (Saint-Andre, P., “The 'acct' URI Scheme,” January 2014.), and this specification treats it such as to exclude various extra strings allowed in addr-spec of RFC 5322 (Resnick, P., Ed., “Internet Message Format,” October 2008.) [RFC5322].



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2.1.2.  Normalization Steps

A string of any other type is interpreted as a URI in one of the forms scheme "://" authority path-abempty [ "?" query ] [ "#" fragment ] or authority path-abempty [ "?" query ] [ "#" fragment ] or scheme ":" path-rootless per RFC 3986 (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.) [RFC3986] and is normalized according to the following rules:

  1. If the user input Identifier does not have an RFC 3986 (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.) [RFC3986] scheme component, the string is interpreted as [userinfo "@"] host [":" port] path-abempty [ "?" query ] [ "#" fragment ] per RFC 3986 (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.) [RFC3986]. Examples are example.com, joe@example.com, example.com/joe, and example.com:8080.
  2. If the userinfo and host components are present and all of the scheme, path, query, port, and fragment components are absent, the acct scheme is assumed. In this case, the normalized URI is formed by prefixing acct: to the string as the scheme. Per The 'acct' URI Scheme (Saint-Andre, P., “The 'acct' URI Scheme,” January 2014.) [I‑D.ietf‑appsawg‑acct‑uri], if there is an at-sign character ('@') in the userinfo component, it needs to be percent-encoded, as described in RFC 3986 (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.) [RFC3986]. Examples are joe@example.com and Jane.Doe@example.com.
  3. For all other inputs without a scheme component, the https scheme is assumed, and the normalized URI is formed by prefixing https:// to the string as the scheme. Examples are example.com, example.com/joe, example.com:8080, and joe@example.com:8080.
  4. When the input contains an explicit scheme such as acct or https that matches the RFC 3986 scheme ":" path-rootless syntax, no input normalization is performed. Examples are https://example.com, https://example.com/joe, https://joe@example.com:8080, and acct:joe@example.com.
  5. If the resulting URI contains a fragment component, it MUST be stripped off, together with the fragment delimiter character "#".

The WebFinger (Jones, P., Salgueiro, G., Jones, M., and J. Smarr, “WebFinger,” September 2013.) [RFC7033] Resource in this case is the resulting URI, and the WebFinger Host is the authority component.

NOTE: Since the definition of authority in RFC 3986 (Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” January 2005.) [RFC3986] is [ userinfo "@" ] host [ ":" port ], it is legal to have a user input identifier like userinfo@host:port, e.g., alice@example.com:8080.



 TOC 

2.2.  Non-Normative Examples



 TOC 

2.2.1.  User Input using E-Mail Address Syntax

To find the Issuer for the given user input in the form of an e-mail address joe@example.com, the WebFinger parameters are as follows:

WebFinger ParameterValue
resource acct:joe@example.com
host example.com
rel http://openid.net/specs/connect/1.0/issuer

Note that in this case, the acct: scheme [I‑D.ietf‑appsawg‑acct‑uri] (Saint-Andre, P., “The 'acct' URI Scheme,” January 2014.) is prepended to the Identifier.

The RP would make the following WebFinger request to discover the Issuer location (with line wraps within lines for display purposes only):

  GET /.well-known/webfinger
    ?resource=acct%3Ajoe%40example.com
    &rel=http%3A%2F%2Fopenid.net%2Fspecs%2Fconnect%2F1.0%2Fissuer
    HTTP/1.1
  Host: example.com

  HTTP/1.1 200 OK
  Content-Type: application/jrd+json

  {
   "subject": "acct:joe@example.com",
   "links":
    [
     {
      "rel": "http://openid.net/specs/connect/1.0/issuer",
      "href": "https://server.example.com"
     }
    ]
  }


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2.2.2.  User Input using URL Syntax

To find the Issuer for the given URL, https://example.com/joe, the WebFinger parameters are as follows:

WebFinger ParameterValue
resource https://example.com/joe
host example.com
rel http://openid.net/specs/connect/1.0/issuer

The RP would make the following WebFinger request to discover the Issuer location (with line wraps within lines for display purposes only):

  GET /.well-known/webfinger
    ?resource=https%3A%2F%2Fexample.com%2Fjoe
    &rel=http%3A%2F%2Fopenid.net%2Fspecs%2Fconnect%2F1.0%2Fissuer
    HTTP/1.1
  Host: example.com

  HTTP/1.1 200 OK
  Content-Type: application/jrd+json

  {
   "subject": "https://example.com/joe",
   "links":
    [
     {
      "rel": "http://openid.net/specs/connect/1.0/issuer",
      "href": "https://server.example.com"
     }
    ]
  }


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2.2.3.  User Input using Hostname and Port Syntax

If the user input is in the form of host:port, e.g., example.com:8080, then it is assumed as the authority component of the URL.

To find the Issuer for the given hostname, example.com:8080, the WebFinger parameters are as follows:

WebFinger ParameterValue
resource https://example.com:8080/
host example.com:8080
rel http://openid.net/specs/connect/1.0/issuer

The RP would make the following WebFinger request to discover the Issuer location (with line wraps within lines for display purposes only):

  GET /.well-known/webfinger
    ?resource=https%3A%2F%2Fexample.com%3A8080%2F
    &rel=http%3A%2F%2Fopenid.net%2Fspecs%2Fconnect%2F1.0%2Fissuer
    HTTP/1.1
  Host: example.com:8080

  HTTP/1.1 200 OK
  Content-Type: application/jrd+json

  {
   "subject": "https://example.com:8080/",
   "links":
    [
     {
      "rel": "http://openid.net/specs/connect/1.0/issuer",
      "href": "https://server.example.com"
     }
    ]
  }


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2.2.4.  User Input using "acct" URI Syntax

To find the Issuer for the given user input in the form of an account URI acct:juliet%40capulet.example@shopping.example.com, the WebFinger parameters are as follows:

WebFinger ParameterValue
resource acct:juliet%40capulet.example@shopping.example.com
host shopping.example.com
rel http://openid.net/specs/connect/1.0/issuer

The RP would make the following WebFinger request to discover the Issuer location (with line wraps within lines for display purposes only):

  GET /.well-known/webfinger
    ?resource=acct%3Ajuliet%2540capulet.example%40shopping.example.com
    &rel=http%3A%2F%2Fopenid.net%2Fspecs%2Fconnect%2F1.0%2Fissuer
    HTTP/1.1
  Host: shopping.example.com

  HTTP/1.1 200 OK
  Content-Type: application/jrd+json

  {
   "subject": "acct:juliet%40capulet.example@shopping.example.com",
   "links":
    [
     {
      "rel": "http://openid.net/specs/connect/1.0/issuer",
      "href": "https://server.example.com"
     }
    ]
  }

NOTE: It is common for sites to use e-mail addresses as local identifiers for accounts at those sites, even though the domain in the e-mail address one controlled by the site. For instance, the site example.org might have a local account named joe@example.com. As of the time of this writing, a discussion is ongoing among WebFinger contributors about the syntax that should be used when discovering information about such accounts with WebFinger. The current thinking seems to be that such accounts would be represented by quoting the '@' character in the userinfo component of the account identifier when constructing the acct: URI representing the account. Such an example is acct:joe%40example.com@example.org. In a future version of this specification, it is possible that normalization rules will be defined allowing End-Users to input values like joe@example.com@example.org to initiate discovery on such accounts.



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3.  OpenID Provider Metadata

OpenID Providers have metadata describing their configuration. These OpenID Provider Metadata values are used by OpenID Connect:

issuer
REQUIRED. URL using the https scheme with no query or fragment component that the OP asserts as its Issuer Identifier. If Issuer discovery is supported (see Section 2 (OpenID Provider Issuer Discovery)), this value MUST be identical to the issuer value returned by WebFinger. This also MUST be identical to the iss Claim value in ID Tokens issued from this Issuer.
authorization_endpoint
REQUIRED. URL of the OP's OAuth 2.0 Authorization Endpoint [OpenID.Core] (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.).
token_endpoint
URL of the OP's OAuth 2.0 Token Endpoint [OpenID.Core] (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.). This is REQUIRED unless only the Implicit Flow is used.
userinfo_endpoint
RECOMMENDED. URL of the OP's UserInfo Endpoint [OpenID.Core] (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.). This URL MUST use the https scheme and MAY contain port, path, and query parameter components.
jwks_uri
REQUIRED. URL of the OP's JSON Web Key Set [JWK] (Jones, M., “JSON Web Key (JWK),” July 2014.) document. This contains the signing key(s) the RP uses to validate signatures from the OP. The JWK Set MAY also contain the Server's encryption key(s), which are used by RPs to encrypt requests to the Server. When both signing and encryption keys are made available, a use (Key Use) parameter value is REQUIRED for all keys in the referenced JWK Set to indicate each key's intended usage. Although some algorithms allow the same key to be used for both signatures and encryption, doing so is NOT RECOMMENDED, as it is less secure. The JWK x5c parameter MAY be used to provide X.509 representations of keys provided. When used, the bare key values MUST still be present and MUST match those in the certificate.
registration_endpoint
RECOMMENDED. URL of the OP's Dynamic Client Registration Endpoint [OpenID.Registration] (Sakimura, N., Bradley, J., and M. Jones, “OpenID Connect Dynamic Client Registration 1.0,” August 2014.).
scopes_supported
RECOMMENDED. JSON array containing a list of the OAuth 2.0 (Hardt, D., “The OAuth 2.0 Authorization Framework,” October 2012.) [RFC6749] scope values that this server supports. The server MUST support the openid scope value. Servers MAY choose not to advertise some supported scope values even when this parameter is used, although those defined in [OpenID.Core] (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.) SHOULD be listed, if supported.
response_types_supported
REQUIRED. JSON array containing a list of the OAuth 2.0 response_type values that this OP supports. Dynamic OpenID Providers MUST support the code, id_token, and the token id_token Response Type values.
response_modes_supported
OPTIONAL. JSON array containing a list of the OAuth 2.0 response_mode values that this OP supports, as specified in OAuth 2.0 Multiple Response Type Encoding Practices (de Medeiros, B., Ed., Scurtescu, M., Tarjan, P., and M. Jones, “OAuth 2.0 Multiple Response Type Encoding Practices,” February 2014.) [OAuth.Responses]. If omitted, the default for Dynamic OpenID Providers is ["query", "fragment"].
grant_types_supported
OPTIONAL. JSON array containing a list of the OAuth 2.0 Grant Type values that this OP supports. Dynamic OpenID Providers MUST support the authorization_code and implicit Grant Type values and MAY support other Grant Types. If omitted, the default value is ["authorization_code", "implicit"].
acr_values_supported
OPTIONAL. JSON array containing a list of the Authentication Context Class References that this OP supports.
subject_types_supported
REQUIRED. JSON array containing a list of the Subject Identifier types that this OP supports. Valid types include pairwise and public.
id_token_signing_alg_values_supported
REQUIRED. JSON array containing a list of the JWS signing algorithms (alg values) supported by the OP for the ID Token to encode the Claims in a JWT [JWT] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” July 2014.). The algorithm RS256 MUST be included. The value none MAY be supported, but MUST NOT be used unless the Response Type used returns no ID Token from the Authorization Endpoint (such as when using the Authorization Code Flow).
id_token_encryption_alg_values_supported
OPTIONAL. JSON array containing a list of the JWE encryption algorithms (alg values) supported by the OP for the ID Token to encode the Claims in a JWT [JWT] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” July 2014.).
id_token_encryption_enc_values_supported
OPTIONAL. JSON array containing a list of the JWE encryption algorithms (enc values) supported by the OP for the ID Token to encode the Claims in a JWT [JWT] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” July 2014.).
userinfo_signing_alg_values_supported
OPTIONAL. JSON array containing a list of the JWS [JWS] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” July 2014.) signing algorithms (alg values) [JWA] (Jones, M., “JSON Web Algorithms (JWA),” July 2014.) supported by the UserInfo Endpoint to encode the Claims in a JWT [JWT] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” July 2014.). The value none MAY be included.
userinfo_encryption_alg_values_supported
OPTIONAL. JSON array containing a list of the JWE [JWE] (Jones, M., Rescorla, E., and J. Hildebrand, “JSON Web Encryption (JWE),” July 2014.) encryption algorithms (alg values) [JWA] (Jones, M., “JSON Web Algorithms (JWA),” July 2014.) supported by the UserInfo Endpoint to encode the Claims in a JWT [JWT] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” July 2014.).
userinfo_encryption_enc_values_supported
OPTIONAL. JSON array containing a list of the JWE encryption algorithms (enc values) [JWA] (Jones, M., “JSON Web Algorithms (JWA),” July 2014.) supported by the UserInfo Endpoint to encode the Claims in a JWT [JWT] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” July 2014.).
request_object_signing_alg_values_supported
OPTIONAL. JSON array containing a list of the JWS signing algorithms (alg values) supported by the OP for Request Objects, which are described in Section 6.1 of OpenID Connect Core 1.0 (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.) [OpenID.Core]. These algorithms are used both when the Request Object is passed by value (using the request parameter) and when it is passed by reference (using the request_uri parameter). Servers SHOULD support none and RS256.
request_object_encryption_alg_values_supported
OPTIONAL. JSON array containing a list of the JWE encryption algorithms (alg values) supported by the OP for Request Objects. These algorithms are used both when the Request Object is passed by value and when it is passed by reference.
request_object_encryption_enc_values_supported
OPTIONAL. JSON array containing a list of the JWE encryption algorithms (enc values) supported by the OP for Request Objects. These algorithms are used both when the Request Object is passed by value and when it is passed by reference.
token_endpoint_auth_methods_supported
OPTIONAL. JSON array containing a list of Client Authentication methods supported by this Token Endpoint. The options are client_secret_post, client_secret_basic, client_secret_jwt, and private_key_jwt, as described in Section 9 of OpenID Connect Core 1.0 (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.) [OpenID.Core]. Other authentication methods MAY be defined by extensions. If omitted, the default is client_secret_basic -- the HTTP Basic Authentication Scheme specified in Section 2.3.1 of OAuth 2.0 (Hardt, D., “The OAuth 2.0 Authorization Framework,” October 2012.) [RFC6749].
token_endpoint_auth_signing_alg_values_supported
OPTIONAL. JSON array containing a list of the JWS signing algorithms (alg values) supported by the Token Endpoint for the signature on the JWT [JWT] (Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” July 2014.) used to authenticate the Client at the Token Endpoint for the private_key_jwt and client_secret_jwt authentication methods. Servers SHOULD support RS256. The value none MUST NOT be used.
display_values_supported
OPTIONAL. JSON array containing a list of the display parameter values that the OpenID Provider supports. These values are described in Section 3.1.2.1 of OpenID Connect Core 1.0 (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.) [OpenID.Core].
claim_types_supported
OPTIONAL. JSON array containing a list of the Claim Types that the OpenID Provider supports. These Claim Types are described in Section 5.6 of OpenID Connect Core 1.0 (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.) [OpenID.Core]. Values defined by this specification are normal, aggregated, and distributed. If omitted, the implementation supports only normal Claims.
claims_supported
RECOMMENDED. JSON array containing a list of the Claim Names of the Claims that the OpenID Provider MAY be able to supply values for. Note that for privacy or other reasons, this might not be an exhaustive list.
service_documentation
OPTIONAL. URL of a page containing human-readable information that developers might want or need to know when using the OpenID Provider. In particular, if the OpenID Provider does not support Dynamic Client Registration, then information on how to register Clients needs to be provided in this documentation.
claims_locales_supported
OPTIONAL. Languages and scripts supported for values in Claims being returned, represented as a JSON array of BCP47 (Phillips, A. and M. Davis, “Tags for Identifying Languages,” September 2009.) [RFC5646] language tag values. Not all languages and scripts are necessarily supported for all Claim values.
ui_locales_supported
OPTIONAL. Languages and scripts supported for the user interface, represented as a JSON array of BCP47 (Phillips, A. and M. Davis, “Tags for Identifying Languages,” September 2009.) [RFC5646] language tag values.
claims_parameter_supported
OPTIONAL. Boolean value specifying whether the OP supports use of the claims parameter, with true indicating support. If omitted, the default value is false.
request_parameter_supported
OPTIONAL. Boolean value specifying whether the OP supports use of the request parameter, with true indicating support. If omitted, the default value is false.
request_uri_parameter_supported
OPTIONAL. Boolean value specifying whether the OP supports use of the request_uri parameter, with true indicating support. If omitted, the default value is true.
require_request_uri_registration
OPTIONAL. Boolean value specifying whether the OP requires any request_uri values used to be pre-registered using the request_uris registration parameter. Pre-registration is REQUIRED when the value is true. If omitted, the default value is false.
op_policy_uri
OPTIONAL. URL that the OpenID Provider provides to the person registering the Client to read about the OP's requirements on how the Relying Party can use the data provided by the OP. The registration process SHOULD display this URL to the person registering the Client if it is given.
op_tos_uri
OPTIONAL. URL that the OpenID Provider provides to the person registering the Client to read about OpenID Provider's terms of service. The registration process SHOULD display this URL to the person registering the Client if it is given.

Additional OpenID Provider Metadata parameters MAY also be used. Some are defined by other specifications, such as OpenID Connect Session Management 1.0 (Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and N. Agarwal, “OpenID Connect Session Management 1.0,” August 2014.) [OpenID.Session].



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4.  Obtaining OpenID Provider Configuration Information

Using the Issuer location discovered as described in Section 2 (OpenID Provider Issuer Discovery) or by other means, the OpenID Provider's configuration information can be retrieved.

OpenID Providers supporting Discovery MUST make a JSON document available at the path formed by concatenating the string /.well-known/openid-configuration to the Issuer. The syntax and semantics of .well-known are defined in RFC 5785 (Nottingham, M. and E. Hammer-Lahav, “Defining Well-Known Uniform Resource Identifiers (URIs),” April 2010.) [RFC5785] and apply to the Issuer value when it contains no path component. openid-configuration MUST point to a JSON document compliant with this specification and MUST be returned using the application/json content type.



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4.1.  OpenID Provider Configuration Request

An OpenID Provider Configuration Document MUST be queried using an HTTP GET request at the previously specified path.

The RP would make the following request to the Issuer https://example.com to obtain its Configuration information, since the Issuer contains no path component:

  GET /.well-known/openid-configuration HTTP/1.1
  Host: example.com

If the Issuer value contains a path component, any terminating / MUST be removed before appending /.well-known/openid-configuration. The RP would make the following request to the Issuer https://example.com/issuer1 to obtain its Configuration information, since the Issuer contains a path component:

  GET /issuer1/.well-known/openid-configuration HTTP/1.1
  Host: example.com

Using path components enables supporting multiple issuers per host. This is required in some multi-tenant hosting configurations. This use of .well-known is for supporting multiple issuers per host; unlike its use in RFC 5785 (Nottingham, M. and E. Hammer-Lahav, “Defining Well-Known Uniform Resource Identifiers (URIs),” April 2010.) [RFC5785], it does not provide general information about the host.



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4.2.  OpenID Provider Configuration Response

The response is a set of Claims about the OpenID Provider's configuration, including all necessary endpoints and public key location information. A successful response MUST use the 200 OK HTTP status code and return a JSON object using the application/json content type that contains a set of Claims as its members that are a subset of the Metadata values defined in Section 3 (OpenID Provider Metadata). Other Claims MAY also be returned.

Claims that return multiple values are represented as JSON arrays. Claims with zero elements MUST be omitted from the response.

An error response uses the applicable HTTP status code value.

The following is a non-normative example response:

  HTTP/1.1 200 OK
  Content-Type: application/json

  {
   "issuer":
     "https://server.example.com",
   "authorization_endpoint":
     "https://server.example.com/connect/authorize",
   "token_endpoint":
     "https://server.example.com/connect/token",
   "token_endpoint_auth_methods_supported":
     ["client_secret_basic", "private_key_jwt"],
   "token_endpoint_auth_signing_alg_values_supported":
     ["RS256", "ES256"],
   "userinfo_endpoint":
     "https://server.example.com/connect/userinfo",
   "check_session_iframe":
     "https://server.example.com/connect/check_session",
   "end_session_endpoint":
     "https://server.example.com/connect/end_session",
   "jwks_uri":
     "https://server.example.com/jwks.json",
   "registration_endpoint":
     "https://server.example.com/connect/register",
   "scopes_supported":
     ["openid", "profile", "email", "address",
      "phone", "offline_access"],
   "response_types_supported":
     ["code", "code id_token", "id_token", "token id_token"],
   "acr_values_supported":
     ["urn:mace:incommon:iap:silver",
      "urn:mace:incommon:iap:bronze"],
   "subject_types_supported":
     ["public", "pairwise"],
   "userinfo_signing_alg_values_supported":
     ["RS256", "ES256", "HS256"],
   "userinfo_encryption_alg_values_supported":
     ["RSA1_5", "A128KW"],
   "userinfo_encryption_enc_values_supported":
     ["A128CBC-HS256", "A128GCM"],
   "id_token_signing_alg_values_supported":
     ["RS256", "ES256", "HS256"],
   "id_token_encryption_alg_values_supported":
     ["RSA1_5", "A128KW"],
   "id_token_encryption_enc_values_supported":
     ["A128CBC-HS256", "A128GCM"],
   "request_object_signing_alg_values_supported":
     ["none", "RS256", "ES256"],
   "display_values_supported":
     ["page", "popup"],
   "claim_types_supported":
     ["normal", "distributed"],
   "claims_supported":
     ["sub", "iss", "auth_time", "acr",
      "name", "given_name", "family_name", "nickname",
      "profile", "picture", "website",
      "email", "email_verified", "locale", "zoneinfo",
      "http://example.info/claims/groups"],
   "claims_parameter_supported":
     true,
   "service_documentation":
     "http://server.example.com/connect/service_documentation.html",
   "ui_locales_supported":
     ["en-US", "en-GB", "en-CA", "fr-FR", "fr-CA"]
  }


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4.3.  OpenID Provider Configuration Validation

If any of the validation procedures defined in this specification fail, any operations requiring the information that failed to correctly validate MUST be aborted and the information that failed to validate MUST NOT be used.

The issuer value returned MUST be identical to the Issuer URL that was directly used to retrieve the configuration information. This MUST also be identical to the iss Claim value in ID Tokens issued from this Issuer.



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5.  String Operations

Processing some OpenID Connect messages requires comparing values in the messages to known values. For example, the member names in the provider configuration response might be compared to specific member names such as issuer. Comparing Unicode strings, however, has significant security implications.

Therefore, comparisons between JSON strings and other Unicode strings MUST be performed as specified below:

  1. Remove any JSON applied escaping to produce an array of Unicode code points.
  2. Unicode Normalization [USA15] (Davis, M., Whistler, K., and M. Dürst, “Unicode Normalization Forms,” 09 2009.) MUST NOT be applied at any point to either the JSON string or to the string it is to be compared against.
  3. Comparisons between the two strings MUST be performed as a Unicode code point to code point equality comparison.



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6.  Implementation Considerations

This specification defines features used by both Relying Parties and OpenID Providers that choose to implement Discovery. All of these Relying Parties and OpenID Providers MUST implement the features that are listed in this specification as being "REQUIRED" or are described with a "MUST". No other implementation considerations for implementations of Discovery are defined by this specification.



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6.1.  Pre-Final IETF Specifications

Implementers should be aware that this specification uses several IETF specifications that are not yet final specifications. Those specifications are:

While every effort will be made to prevent breaking changes to these specifications, should they occur, OpenID Connect implementations should continue to use the specifically referenced draft versions above in preference to the final versions, unless using a possible future OpenID Connect profile or specification that updates some or all of these references.



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7.  Security Considerations



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7.1.  TLS Requirements

Implementations MUST support TLS. Which version(s) ought to be implemented will vary over time, and depend on the widespread deployment and known security vulnerabilities at the time of implementation. At the time of this writing, TLS version 1.2 [RFC5246] (Dierks, T. and E. Rescorla, “The Transport Layer Security (TLS) Protocol Version 1.2,” August 2008.) is the most recent version, but has very limited actual deployment, and might not be readily available in implementation toolkits. TLS version 1.0 [RFC2246] (Dierks, T. and C. Allen, “The TLS Protocol Version 1.0,” January 1999.) is the most widely deployed version, and will give the broadest interoperability.

To protect against information disclosure and tampering, confidentiality protection MUST be applied using TLS with a ciphersuite that provides confidentiality and integrity protection.

Whenever TLS is used, a TLS server certificate check MUST be performed, per RFC 6125 (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),” March 2011.) [RFC6125].



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7.2.  Impersonation Attacks

TLS certificate checking MUST be performed by the RP, as described in Section 7.1 (TLS Requirements), when making an OpenID Provider Configuration Request. Checking that the server certificate is valid for the Issuer URL prevents man-in-middle and DNS-based attacks. These attacks could cause an RP to be tricked into using an attacker's keys and endpoints, which would enable impersonation of the legitimate Issuer. If an attacker can accomplish this, they can access the accounts of any existing users at the affected RP that can be logged into using the OP that they are impersonating.

An attacker may also attempt to impersonate an OpenID Provider by publishing a Discovery document that contains an issuer Claim using the Issuer URL of the OP being impersonated, but with its own endpoints and signing keys. This would enable it to issue ID Tokens as that OP, if accepted by the RP. To prevent this, RPs MUST ensure that the Issuer URL they are using for the Configuration Request exactly matches the value of the issuer Claim in the OP Metadata document received by the RP and that this also exactly matches the iss Claim value in ID Tokens that are supposed to be from that Issuer.



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8.  IANA Considerations



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8.1.  Well-Known URI Registry

This specification registers the well-known URI defined in Section 4 (Obtaining OpenID Provider Configuration Information) in the IANA Well-Known URI registry defined in RFC 5785 (Nottingham, M. and E. Hammer-Lahav, “Defining Well-Known Uniform Resource Identifiers (URIs),” April 2010.) [RFC5785].



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8.1.1.  Registry Contents



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9.  References



 TOC 

9.1. Normative References

[I-D.ietf-appsawg-acct-uri] Saint-Andre, P., “The 'acct' URI Scheme,” draft-ietf-appsawg-acct-uri-07 (work in progress), January 2014 (TXT).
[JWA] Jones, M., “JSON Web Algorithms (JWA),” draft-ietf-jose-json-web-algorithms (work in progress), July 2014 (HTML).
[JWE] Jones, M., Rescorla, E., and J. Hildebrand, “JSON Web Encryption (JWE),” draft-ietf-jose-json-web-encryption (work in progress), July 2014 (HTML).
[JWK] Jones, M., “JSON Web Key (JWK),” draft-ietf-jose-json-web-key (work in progress), July 2014 (HTML).
[JWS] Jones, M., Bradley, J., and N. Sakimura, “JSON Web Signature (JWS),” draft-ietf-jose-json-web-signature (work in progress), July 2014 (HTML).
[JWT] Jones, M., Bradley, J., and N. Sakimura, “JSON Web Token (JWT),” draft-ietf-oauth-json-web-token (work in progress), July 2014 (HTML).
[OAuth.Responses] de Medeiros, B., Ed., Scurtescu, M., Tarjan, P., and M. Jones, “OAuth 2.0 Multiple Response Type Encoding Practices,” February 2014.
[OpenID.Core] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and C. Mortimore, “OpenID Connect Core 1.0,” August 2014.
[OpenID.Registration] Sakimura, N., Bradley, J., and M. Jones, “OpenID Connect Dynamic Client Registration 1.0,” August 2014.
[RFC2119] Bradner, S., “Key words for use in RFCs to Indicate Requirement Levels,” BCP 14, RFC 2119, March 1997 (TXT, HTML, XML).
[RFC2246] Dierks, T. and C. Allen, “The TLS Protocol Version 1.0,” RFC 2246, January 1999 (TXT).
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, “Uniform Resource Identifier (URI): Generic Syntax,” STD 66, RFC 3986, January 2005 (TXT, HTML, XML).
[RFC5246] Dierks, T. and E. Rescorla, “The Transport Layer Security (TLS) Protocol Version 1.2,” RFC 5246, August 2008 (TXT).
[RFC5322] Resnick, P., Ed., “Internet Message Format,” RFC 5322, October 2008 (TXT, HTML, XML).
[RFC5646] Phillips, A. and M. Davis, “Tags for Identifying Languages,” BCP 47, RFC 5646, September 2009 (TXT).
[RFC5785] Nottingham, M. and E. Hammer-Lahav, “Defining Well-Known Uniform Resource Identifiers (URIs),” RFC 5785, April 2010 (TXT).
[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, March 2011 (TXT).
[RFC6749] Hardt, D., “The OAuth 2.0 Authorization Framework,” RFC 6749, October 2012 (TXT).
[RFC7033] Jones, P., Salgueiro, G., Jones, M., and J. Smarr, “WebFinger,” RFC 7033, September 2013 (TXT).
[USA15] Davis, M., Whistler, K., and M. Dürst, “Unicode Normalization Forms,” Unicode Standard Annex 15, 09 2009.


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9.2. Informative References

[OpenID.Session] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B., and N. Agarwal, “OpenID Connect Session Management 1.0,” August 2014.
[XRI_Syntax_2.0] Reed, D. and D. McAlpin, “Extensible Resource Identifier (XRI) Syntax V2.0,” November 2005 (HTML, PDF).


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Appendix A.  Acknowledgements

The OpenID Community would like to thank the following people for their contributions to this specification:

Andrew Arnott (andarno@microsoft.com), Microsoft

Dirk Balfanz (balfanz@google.com), Google

Casper Biering (cb@peercraft.com), Peercraft

John Bradley (ve7jtb@ve7jtb.com), Ping Identity

Johnny Bufu (jbufu@janrain.com), Janrain

Brian Campbell (bcampbell@pingidentity.com), Ping Identity

Blaine Cook (romeda@gmail.com), Independent

Breno de Medeiros (breno@google.com), Google

Pamela Dingle (pdingle@pingidentity.com), Ping Identity

Vladimir Dzhuvinov (vladimir@nimbusds.com), Nimbus Directory Services

George Fletcher (george.fletcher@corp.aol.com), AOL

Dick Hardt (dick.hardt@gmail.com), Independent

Roland Hedberg (roland.hedberg@adm.umu.se), University of Umea

Edmund Jay (ejay@mgi1.com), Illumila

Michael B. Jones (mbj@microsoft.com), Microsoft

Torsten Lodderstedt (t.lodderstedt@telekom.de), Deutsche Telekom

Nov Matake (nov@matake.jp), Independent

Chuck Mortimore (cmortimore@salesforce.com), Salesforce

Anthony Nadalin (tonynad@microsoft.com), Microsoft

Axel Nennker (axel.nennker@telekom.de), Deutsche Telekom

John Panzer (jpanzer@google.com), Google

Justin Richer (jricher@mitre.org), MITRE

Nat Sakimura (n-sakimura@nri.co.jp), Nomura Research Institute, Ltd.

Owen Shepherd (owen.shepherd@e43.eu), Independent

Andreas Åkre Solberg (andreas.solberg@uninett.no), UNINET

Kick Willemse (k.willemse@evidos.nl), Evidos B.V.



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Appendix B.  Notices

Copyright (c) 2014 The OpenID Foundation.

The OpenID Foundation (OIDF) grants to any Contributor, developer, implementer, or other interested party a non-exclusive, royalty free, worldwide copyright license to reproduce, prepare derivative works from, distribute, perform and display, this Implementers Draft or Final Specification solely for the purposes of (i) developing specifications, and (ii) implementing Implementers Drafts and Final Specifications based on such documents, provided that attribution be made to the OIDF as the source of the material, but that such attribution does not indicate an endorsement by the OIDF.

The technology described in this specification was made available from contributions from various sources, including members of the OpenID Foundation and others. Although the OpenID Foundation has taken steps to help ensure that the technology is available for distribution, it takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this specification or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any independent effort to identify any such rights. The OpenID Foundation and the contributors to this specification make no (and hereby expressly disclaim any) warranties (express, implied, or otherwise), including implied warranties of merchantability, non-infringement, fitness for a particular purpose, or title, related to this specification, and the entire risk as to implementing this specification is assumed by the implementer. The OpenID Intellectual Property Rights policy requires contributors to offer a patent promise not to assert certain patent claims against other contributors and against implementers. The OpenID Foundation invites any interested party to bring to its attention any copyrights, patents, patent applications, or other proprietary rights that may cover technology that may be required to practice this specification.



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Appendix C.  Document History

[[ To be removed from the approved errata ]]

-24

-23

-22



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Authors' Addresses

  Nat Sakimura
  Nomura Research Institute, Ltd.
Email:  n-sakimura@nri.co.jp
URI:  http://nat.sakimura.org/
  
  John Bradley
  Ping Identity
Email:  ve7jtb@ve7jtb.com
URI:  http://www.thread-safe.com/
  
  Michael B. Jones
  Microsoft
Email:  mbj@microsoft.com
URI:  http://self-issued.info/
  
  Edmund Jay
  Illumila
Email:  ejay@mgi1.com