The XAuth Protocol

2.1. Parties

The parties and their relationships to each other:¶

+--------+                           +------------+
|  User  |                           |  Resource  |
|        |                           | Owner (RO) |
+--------+                           +------------+
    |      \                       /      |
    |       \                     /       |
    |        \                   /        |
    |         \                 /         |
+--------+     +---------------+     +------------+
| Client |---->|     Grant     | _ _ |  Resource  |
|        |<----|  Server (GS)  |     |   Server   |
|        |     +---------------+     |    (RS)    |
|        |-------------------------->|            |
|        |<--------------------------|            |
+--------+                           +------------+

• User - the person interacting with the Client who has delegated access to identity claims about themselves to the Grant Server (GS), and can authenticate at the GS.¶
• Client - requests a Grant from the GS to access one or more Resource Servers (RSs), and/or identity claims about the User. The Client can create, retrieve, update, and delete a Grant. When a Grant is created, the Client receives from the GS the granted access token(s) for the RS(s), and identity claims about the User. The Client uses an access token to access the RS. There are two types of Clients: Registered Clients and Dynamic Clients. All Clients have a key to authenticate with the Grant Server.¶
• Registered Client - a Client that has registered with the GS and has a Client ID to identify itself, and can prove it possesses a key that is linked to the Client ID. The GS may have different policies for what different Registered Clients can request. A Registered Client MAY be interacting with a User.¶
• Dynamic Client - a Client that has not been registered with the GS, and each instance will generate it's own key pair so it can prove it is the same instance of the Client on subsequent requests, and to requests of a Resource Server. A single-page application with no server is an example of a Dynamic Client. A Dynamic Client MUST be interacting with a User.¶
• Grant Server (GS) - manages Grants for access to APIs at RSs and release of identity claims about the User. The GS may require explicit consent from the RO or User to provide these to the Client. An GS may support Registered Clients and/or Dynamic Clients. The GS is a combination of the Authorization Server (AS) in OAuth 2.0, and the OpenID Provider (OP) in OpenID Connect.¶
• Resource Server (RS) - has API resources that require an access token from the GS. Owned by the Resource Owner.¶
• Resource Owner (RO) - owns resources at the RS, and has delegated RS access management to the GS. The RO may be the same entity as the User, or may be a different entity that the GS interacts with independently. GS and RO interactions are out of scope of this document.¶

2.2. Reused Terms

• access token - an access token as defined in [RFC6749] Section 1.4.¶
• Claim - a Claim as defined in [OIDC] Section 5. Claims may be issued by the GS, or by other issuers.¶
• Client ID - a GS unique identifier for a Registered Client as defined in [RFC6749] Section 2.2.¶
• ID Token - an ID Token as defined in [OIDC] Section 2.¶
• NumericDate - a NumericDate as defined in [RFC7519] Section 2.¶
• authN - short for authentication.¶
• authZ - short for authorization.¶

2.3. New Terms

• GS URI - the endpoint at the GS the Client calls to create a Grant. The unique identifier for the GS.¶
• Grant - the user identity claims and/or RS authorizations the GS has granted to the Client.¶
• Grant URI - the URI that represents the Grant. The Grant URI MUST start with the GS URI.¶
• Authorization - the access granted by the RO to the Client. Contains an access token.¶
• AuthZ URI - the URI that represents the Authorization the Client was granted by the RO. The AuthZ URI MUST start with the GS URI. The AuthZ URI is used to refresh, update, and delete an access token.¶
• interaction - [Editor: what do we really mean by this term?]¶

3.1. Create Grant

The Client requests a Grant from the GS that requires User interaction:¶

+--------+                                  +-------+
| Client |                                  |  GS   |
|        |--(1)--- Create Grant ----------->|       |
|        |                                  |  (2)  |
|        |<--- Interaction Response ---(3)--|  eval |
|        |                                  |       |
|        |--(4)--- Read Grant ------------->|       |         +------+
|        |                                  |       |         | User |
|        |--(5)--- Interaction Transfer --- | - - - | ------->|      |
|        |                                  |       |<--(6)-->|      |
|        |                                  |       |  authN  |      |
|        |                                  |       |<--(7)-->|      |
|        |                                  |       |  authZ  |      |
|        |<--- Interaction Transfer ---(8)- | - - - | --------|      |
|        |                                  |       |         |      |
|        |<--------- Grant Response ---(9)--|       |         +------+
|        |                                  |       |
+--------+                                  +-------+

1. Create Grant The Client creates a Grant Request (Section 5.1) and sends it with an HTTP POST to the GS GS URI.¶
2. Grant Request Evaluation The GS processes the request to determine if it will send a Interaction Response, Wait Response, or a Grant Response. The GS determines that interaction with the User is required and sends an Interaction Response. (For readability, this step is not described in the following sequences)¶
3. Interaction Response The GS sends an Interaction Response (Section 7.2) containing the Grant URI and an interaction object.¶
4. Read Grant The Client does an HTTP GET of the Grant URI (Section 5.2).¶
5. Interaction Transfer The Client transfers User interaction to the GS.¶
6. User Authentication The GS authenticates the User.¶
7. User Authorization If required, the GS interacts with the User to determine which identity claims and/or authorizations in the Grant Request are to be granted.¶
8. Interaction Transfer The GS transfers User interaction to the Client.¶
9. Grant Response The GS responds with a Grant Response (Section 7.1).¶

3.2. Reciprocal Grant

Party A and Party B are both a Client and a GS, and each Client would like a Grant for the other GS. Party A starts off being the Client per Create Grant Section 3.1. Party B then includes a Reciprocal Request in its Grant Response. Party A then gets authorization from the User and returns a Grant URI to Party B. Party A and B swap roles, and Party B's Client obtains the Grant from Party A's GS.¶

                Party A                                    Party B
               +--------+                                 +--------+
               | Client |                                 |   GS   |
               ~ ~ ~ ~ ~ ~     Same as steps 1 - 8 of    ~ ~ ~ ~ ~ ~
+------+       |        |        Create Grant above       |        |
| User |       |        |                                 |        |
|      |<----- | - - -  | -- Interaction Transfer ------- |        |
|      |       |        |                                 |        |
|      |       |        |<------- Grant Response ---(1)---|        |
|      |       |        |      Reciprocal Grant Request   |        |
|      |<-(2)->|        |                                 |        |
|      | AuthZ |        |---(3)--- Update Grant --------->|        |
+------+       |        |   Reciprocal Grant Response     |        |
               |        |                                 |        |
               |        |<-- Empty Grant Response ---(4)--|        |
               |        |                                 |        |
               +--------+       (5) Swap Roles            +--------+
               |   GS   |                                 | Client |
               |        |<------------ Read Grant ---(6)--|        |
               |        |                                 |        |
               |        |--(7)--- Grant Response -------->|        |
               |        |                                 |        |
               +--------+                                 +--------+

1. Grant Response Party B responds with a Grant Response including a Reciprocal Object Section 7.4.6 requesting its own Grant.¶
2. User Authorization If required, Party A interacts with the User to determine which identity claims and/or authorizations in the Grant Request are to be granted to Party B.¶
3. Update Grant Party A sends an Update Grant request containing the Grant URI in the Reciprocal object Section 5.5.7.¶
4. Grant Response Party B responds with an Empty Grant Response as there were no other requests in the Update Grant.¶
5. Swap Roles Party A now acts as a GS, Party B as a Client.¶
6. Read Grant Party B does an HTTP GET of the Grant URI (Section 5.2).¶
7. Grant Response Party A responds with a Grant Response (Section 7.1).¶

3.3. GS Initiated Grant

The User is at the GS, and wants to interact with a Registered Client. The GS can redirect the User to the Client:¶

+--------+                                  +-------+         +------+
| Client |                                  |  GS   |         | User |
|        |                                  |       |<--(1)-->|      |
|        |                                  |       |         |      |
|        |<----- GS Initiation Redirect --- | - - - | --(2)---|      |
|   (3)  |                                  |       |         |      |
| verify |--(4)--- Read Grant ------------->|       |         +------+
|        |                                  |       |
|        |<--------- Grant Response --(5)---|       |
|        |                                  |       |
+--------+                                  +-------+

1. User Interaction The GS interacts with the User to determine the Client and what identity claims and authorizations to provide. The GS creates a Grant and corresponding Grant URI.¶
2. GS Initiated Redirect The GS redirects the User to the Client's interaction_uri, adding a query parameter with the name "Grant URI" and the value being the URL encoded Grant URI.¶
3. Client Verification The Client verifies the Grant URI is from an GS the Client trusts, and starts with the GS GS URI.¶
4. Read Grant The Client does an HTTP GET of the Grant URI (Section 5.2).¶
5. Grant Response The GS responds with a Grant Response (Section 7.1).¶

See Section 6 for more details.¶

3.4. Create and Update

The Client requests an identity claim to determine who the User is. Once the Client learns who the User is, and the Client updates the Grant for additional identity claims which the GS prompts the User for and returns to the Client. Once those are received, the Client updates the Grant with the remaining identity claims required.¶

+--------+                                  +-------+
| Client |                                  |  GS   |
|        |--(1)--- Create Grant ----------->|       |
|        |  "interaction"."keep":true       |       |
|        |                                  |       |
|        |<--- Interaction Response ---(2)--|       |
|        |                                  |       |
|        |--(3)--- Read Grant ------------->|       |         +------+
|        |                                  |       |         | User |
|        |--(4)--- Interaction Transfer --- | - - - | ------->|      |
|        |                                  |       |         |      |
|        |                                  |       |<--(5)-->|      |
|        |                                  |       |  authN  |      |
|        |<--------- Grant Response ---(6)--|       |         |      |
|  (7)   |                                  |       |         |      |
|  eval  |--(8)--- Update Grant ----------->|       |         |      |
|        |  "interaction"."keep":true       |       |<--(9)-->|      |
|        |                                  |       |  authZ  |      |
|        |<--------- Grant Response --(10)--|       |         |      |
|  (11)  |                                  |       |         |      |
|  eval  |--(12)-- Update Grant ----------->|       |         |      |
|        |  "interaction"."keep":false      |       |<--(13)->|      |
|        |                                  |       |  authZ  |      |
|        |                                  |       |         |      |
|        |<--- Interaction Transfer --(14)- | - - - | --------|      |
|        |                                  |       |         |      |
|        |<--------- Grant Response --(15)--|       |         +------+
|        |                                  |       |
+--------+                                  +-------+

1. Create Grant The Client creates a Grant Request (Section 5.1) including an identity claim and "interaction"."keep":true, and sends it with an HTTP POST to the GS GS URI.¶
2. Interaction Response The GS sends an Interaction Response (Section 7.2) containing the Grant URI, an interaction object, and "interaction"."keep":true.¶
3. Read Grant The Client does an HTTP GET of the Grant URI (Section 5.2).¶
4. Interaction Transfer The Client transfers User interaction to the GS.¶
5. User Authentication The GS authenticates the User.¶
6. Grant Response The GS responds with a Grant Response (Section 7.1) including the identity claim from User authentication and "interaction"."keep":true.¶
7. Grant Evaluation The Client queries its User database and does not find a User record matching the identity claim.¶
8. Update Grant The Client creates an Update Grant Request (Section 5.3) including the initial identity claims required and "interaction"."keep":true, and sends it with an HTTP PUT to the Grant URI.¶
9. User AuthN The GS interacts with the User to determine which identity claims in the Update Grant Request are to be granted.¶
10. Grant Response The GS responds with a Grant Response (Section 7.1) including the identity claims released by the User and "interaction"."keep":true.¶
11. Grant Evaluation The Client evaluates the identity claims in the Grant Response and determines the remaining User identity claim required.¶
12. Update Grant The Client creates an Update Grant Request (Section 5.3) including the remaining required identity claims and "interaction"."keep":false, and sends it with an HTTP PUT to the Grant URI.¶
13. User AuthZ The GS interacts with the User to determine which identity claims in the Update Grant Request are to be granted.¶
14. Interaction Transfer The GS transfers User interaction to the Client.¶
15. Grant Response The GS responds with a Grant Response (Section 7.1) including the identity claims released by the User.¶

3.5. Create and Delete

The Client requests an identity claim to determine who the User is. Once the Client learns who the User is, and the Client knows it has all the identity claims and authorizations needed, the Client deletes the Grant which prompts the GS to transfer the interaction back to the Client.¶

+--------+                                  +-------+
| Client |                                  |  GS   |
|        |--(1)--- Create Grant ----------->|       |
|        |  "interaction"."keep":true       |       |
|        |                                  |       |
|        |<--- Interaction Response ---(2)--|       |
|        |                                  |       |
|        |--(3)--- Read Grant ------------->|       |         +------+
|        |                                  |       |         | User |
|        |--(4)--- Interaction Transfer --- | - - - | ------->|      |
|        |                                  |       |         |      |
|        |                                  |       |<--(5)-->|      |
|        |                                  |       |  authN  |      |
|        |<--------- Grant Response ---(6)--|       |         |      |
|  (7)   |                                  |       |         |      |
|  eval  |--(8)--- Delete Grant ----------->|       |         |      |
|        |<------- Delete Response ---------|       |         |      |
|        |                                  |       |         |      |
|        |<--- Interaction Transfer ---(9)- | - - - | --------|      |
|        |                                  |       |         |      |
+--------+                                  +-------+         +------+

1. Create Grant The Client creates a Grant Request (Section 5.1) including an identity claim and "interaction"."keep":true, and sends it with an HTTP POST to the GS GS URI.¶
2. Interaction Response The GS sends an Interaction Response (Section 7.2) containing the Grant URI, an interaction object, and "interaction"."keep":true.¶
3. Read Grant The Client does an HTTP GET of the Grant URI (Section 5.2).¶
4. Interaction Transfer The Client transfers User interaction to the GS.¶
5. User Authentication The GS authenticates the User.¶
6. Grant Response The GS responds with a Grant Response (Section 7.1) including the identity claim from User authentication and "interaction"."keep":true.¶
7. Grant Evaluation The Client queries its User database and finds the User record matching the identity claim, and that no additional claims or authorizations are required.¶
8. Delete Grant The Client no longer needs the Grant and decides to Delete Grant (Section 5.4) by sending an HTTP DELETE to the Grant URI. If the GS responds with success the Grant no longer exists.¶

3.6. Create, Discover, and Delete

The Client wants to discover if the GS has a User with a given identifier. If not, it will abort the request and not transfer interaction to the GS.¶

+--------+                                  +-------+
| Client |                                  |  GS   |
|        |--(1)--- Create Grant ----------->|       |
|        |  "user"."exists":true            |       |
|        |                                  |       |
|        |<--- Interaction Response ---(2)--|       |
|        |     "user"."exists":false        |       |
|        |                                  |       |
|        |--(3)--- Delete Grant ----------->|       |
|        |<------- Delete Response ---------|       |
|        |                                  |       |
+--------+                                  +-------+

1. Create Grant The Client creates a Grant Request (Section 5.1) including an identity claim request, a User identifier, and "user"."exists":true. The Client sends it with an HTTP POST to the GS GS URI.¶
2. Interaction Response The GS sends an Interaction Response (Section 7.2) containing the Grant URI, an interaction object, and "user"."exists":false.¶
3. Delete Grant The Client determines the GS cannot fulfil its Grant Request, and decides to Delete Grant (Section 5.4) by sending an HTTP DELETE to the Grant URI. If the GS responds with success the Grant no longer exists.¶

3.7. Create and Wait

The Client wants access to resources that require the GS to interact with the RO, which may not happen immediately, so the GS instructs the Client to wait and check back later.¶

+--------+                                  +-------+
| Client |                                  |  GS   |
|        |--(1)--- Create Grant ----------->|       |
|        |                                  |       |
|        |<---------- Wait Response ---(2)--|       |         +------+
|  (3)   |                                  |       |         |  RO  |
|  Wait  |                                  |       |<--(4)-->|      |
|        |                                  |       |  authZ  |      |
|        |--(5)--- Read Grant ------------->|       |         +------+
|        |                                  |       |
|        |<--------- Grant Response --(6)---|       |
|        |                                  |       |
+--------+                                  +-------+

1. Create Grant The Client creates a Grant Request (Section 5.1) and sends it with an HTTP POST to the GS GS URI.¶
2. Wait Response The GS sends an Interaction Response (Section 7.3) containing the Grant URI and wait time.¶
3. Client Waits The Client waits the wait time.¶
4. RO AuthZ The GS interacts with the RO to determine which identity claims in the Grant Request are to be granted.¶
5. Read Grant The Client does an HTTP GET of the Grant URI (Section 5.2).¶
6. Grant Response The GS responds with a Grant Response (Section 7.1).¶

3.8. Read Grant

The Client wants to acquire fresh identity claims and authorizations in the Grant. No User or RO interaction is required as no new consent or authorization is required.¶

+--------+                                  +-------+
| Client |                                  |  GS   |
|        |--(1)--- Read Grant ------------->|       |
|        |                                  |       |
|        |<--------- Grant Response --(2)---|       |
|        |                                  |       |
+--------+                                  +-------+

1. Read Grant The Client does an HTTP GET of the Grant URI (Section 5.2).¶
2. Grant Response The GS responds with a Grant Response (Section 7.1) containing updated identity claims and authorizations.¶

3.9. Access Token Refresh

The Client has an access token and uses it to access resources at an RS. The access token expires, and the Client acquires a fresh access token from the GS.¶

+--------+                             +----------+
| Client |                             | Resource |
|        |--(1)--- Access Resource --->|  Server  |
|        |<------- Resource Response --|   (RS)   |
|        |                             |          |
|        |--(2)--- Access Resource --->|          |
|        |<------- Error Response -----|          |
|        |                             |          |
|        |                             +----------+  +-------+
|        |                                           |  GS   |
|        |--(3)--- Refresh AuthZ ------------------->|       |
|        |<------- AuthZ Response -------------------|       |
|        |                                           |       |
+--------+                                           +-------+

1. Resource Request The Client accesses the RS with the access token per Section 8 and receives a response from the RS.¶
2. Resource Request The Client attempts to access the RS, but receives an error indicating the access token has expired.¶
3. Refresh AuthZ If the Client received an AuthZ URI in the Response JSON "authorization" object (Section 7.4.3), the Client can Refresh AuthZ (Section 5.6) with an HTTP GET to the AuthZ URI and receive an Response JSON "authorization" object" (Section 7.4.3) with a fresh access token.¶

3.10. GS API Table

[ Editor: is there value in an API for listing a Client's Grants? eg:]¶

List Grants     GET     GS URI    JSON array of Grant URIs

5.1. Create Grant

The Client creates a Grant by doing an HTTP POST of a JSON [RFC8259] document to the GS URI.¶

The JSON document MUST include the following from the Request JSON Section 5.5:¶

• iat¶
• nonce¶
• uri set to the GS URI¶
• client¶

and MAY include the following from Request JSON Section 5.5¶

• user¶
• interaction¶
• authorization or authorizations¶
• claims¶
• reciprocal¶

The GS MUST respond with one of Grant Response Section 7.1, Interaction Response Section 7.2, Wait Response Section 7.3, or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

Following is a non-normative example where the Client wants to interact with the User with a popup and is requesting identity claims about the User and read access to the User's contacts:¶

Example 1

{
    "iat"       : 15790460234,
    "uri"       : "https://as.example/endpoint",
    "nonce"     : "f6a60810-3d07-41ac-81e7-b958c0dd21e4",
    "client": {
        "display": {
            "name"  : "SPA Display Name",
            "uri"   : "https://spa.example/about"
        }
    },
    "interaction": {
        "type"      : "popup"
    },
    "authorization": {
        "type"      : "oauth_scope",
        "scope"     : "read_contacts"
    },
    "claims": {
        "oidc": {
            "id_token" : {
                "email"          : { "essential" : true },
                "email_verified" : { "essential" : true }
            },
            "userinfo" : {
                "name"           : { "essential" : true },
                "picture"        : null
            }
        }
    }
}

Following is a non-normative example where the Client is requesting the GS to keep the interaction with the User after returning the ID Token so the Client can update the Grant, and is also asking if the user exists:¶

Example 2

{
    "iat"       : 15790460234,
    "uri"       : "https://as.example/endpoint",
    "nonce"     : "5c9360a5-9065-4f7b-a330-5713909e06c6",
    "client": {
        "id"        : "di3872h34dkJW"
    },
    "interaction": {
        "keep"          : true,
        "type"          : "redirect",
        "redirect_uri"  : "https://web.example/return"
    },
    "user": {
        "identifiers": {
            "email" : "jane.doe@example.com"
        },
        "exists"    : true
    },
    "claims"    : { "oidc": { "id_token" : {} } }
}

5.2. Read Grant

The Client reads a Grant by doing an HTTP GET of the corresponding Grant URI.¶

The GS MUST respond with one of Grant Response Section 7.1, Interaction Response Section 7.2, Wait Response Section 7.3, or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

5.3. Update Grant

The Client updates a Grant by doing an HTTP PUT of a JSON document to the corresponding Grant URI.¶

The JSON document MUST include the following from the Request JSON Section 5.5¶

• iat¶
• uri set to the Grant URI¶

and MAY include the following from Request JSON Section 5.5¶

• user¶
• interaction¶
• authorization or authorizations¶
• claims¶
• reciprocal¶

The GS MUST respond with one of Grant Response Section 7.1, Interaction Response Section 7.2, Wait Response Section 7.3, or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

Following is a non-normative example where the Client made an "interaction"."keep":true request, and now wants to update the request with additional claims:¶

Example 3

{
    "iat"       : 15790460234,
    "uri"       : "https://as.example/endpoint/grant/example3",
    "claims": {
        "oidc": {
            "userinfo" : {
                "email"          : { "essential" : true },
                "name"           : { "essential" : true },
                "picture"        : null
            }
        }
    }
}

5.4. Delete Grant

The Client deletes a Grant by doing an HTTP DELETE of the corresponding Grant URI.¶

The GS MUST respond with OK 200, or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

5.5. Request JSON

[Editor: do we want to reuse the JWT claims "iat", "jti", etc.? ]¶

• iat - the time of the request as a NumericDate.¶
• nonce - a unique identifier for this request. Note the Grant Response MUST contain a matching nonce attribute value.¶
• uri - the GS URI if in a Create Grant Section 5.1, or the Grant URI if in an Update Grant Section 5.3.¶

5.6. Refresh Authorization

The Client updates an Authorization by doing an HTTP GET to the corresponding AuthZ URI.¶

The GS MUST respond with an Response JSON "authorization" object Section 7.4.3, or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

5.7. Update Authorization

The Client updates an Authorization by doing an HTTP PUT to the corresponding AuthZ URI of the following JSON. All of the following MUST be included.¶

• iat - the time of the response as a NumericDate.¶
• uri - the AuthZ URI.¶
• authorization - the new authorization requested per the Request JSON "authorization" object Section 5.5.4.¶

The GS MUST respond with an Response JSON "authorization" object Section 7.4.3, or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

5.8. Delete Authorization

The Client deletes an Authorization by doing an HTTP DELETE to the corresponding AuthZ URI.¶

The GS MUST respond with OK 200, or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

5.9. GS Options

The Client can get the metadata for the GS by doing an HTTP OPTIONS of the corresponding GS URI. This is the only API where the GS MAY respond to an unauthenticated request.¶

The GS MUST respond with the the following JSON document:¶

[Editor: this section is a work in progress]¶

• uri - the GS URI.¶
• client_authentication - an array of the Client Authentication mechanisms supported by the GS¶
• interactions - an array of the interaction types supported by the GS.¶

• authorization - an object containing the authorizations the Client may request from the GS, if any.¶

  • Details TBD¶

• claims - an object containing the identity claims the Client may request from the GS, if any, and what public keys the claims will be signed with.¶

  • Details TBD¶
• algorithms - a list of the cryptographic algorithms supported by the GS.¶

• features - an object containing feature support¶

  • user_exists - boolean indicating if "user"."exists" is supported.¶
  • authorizations - boolean indicating if a request for multiple authorizations is supported.¶

[Editor: keys used by Client to encrypt requests, or verify signed responses?]¶

[Editor: namespace metadata for extensions?]¶

or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

5.10. Grant Options

The Client can get the metadata for the Grant by doing an HTTP OPTIONS of the corresponding Grant URI.¶

The GS MUST respond with the the following JSON document:¶

• verbs - an array of the HTTP verbs supported at the GS URI.¶

or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

5.11. AuthZ Options

The Client can get the metadata for the AuthZ by doing an HTTP OPTIONS of the corresponding AuthZ URI.¶

The GS MUST respond with the the following JSON document:¶

• verbs - an array of the HTTP verbs supported at the GS URI.¶

or one of the following errors:¶

• TBD¶

from Error Responses Section 9.¶

5.12. Request Verification

On receipt of a request, the GS MUST verify the following:¶

• TBD¶

7.1. Grant Response

The Grant Response MUST include the following from the Response JSON Section 7.4¶

• iat¶
• nonce¶
• uri¶
• expires_in¶

and MAY include the following from the Response JSON Section 7.4¶

• authorization or authorizations¶
• claims¶
• reciprocal¶

Example non-normative Grant Response JSON document for Example 1 in Section 3.1:¶

{
    "iat"           : 15790460234,
    "nonce"         : "f6a60810-3d07-41ac-81e7-b958c0dd21e4",
    "uri"           : "https://as.example/endpoint/grant/example1",
    "expires_in"    : 300
    "authorization": {
        "type"          : "oauth_scope",
        "scope"         : "read_contacts",
        "expires_in"    : 3600,
        "mechanism"     : "bearer",
        "token"         : "eyJJ2D6.example.access.token.mZf9p"
    },
    "claims": {
        "oidc": {
            "id_token"      : "eyJhbUzI1N.example.id.token.YRw5DFdbW",
            "userinfo" : {
                "name"      : "John Doe",
                "picture"   : "https://photos.example/p/eyJzdkiO"
            }
        }
    }
}

Example non-normative Grant Response JSON document for Example 2 in Section 3.1:¶

{
    "iat"   : 15790460234,
    "nonce" : "5c9360a5-9065-4f7b-a330-5713909e06c6",
    "uri"   : "https://as.example/endpoint/grant/example2",
    "authorization": {
        "type"          : "oauth_scope",
        "scope"         : "read_calendar write_calendar",
        "expires_in"    : 3600,
        "mechanism"     : "jose",
        "token"         : "eyJJ2D6.example.access.token.mZf9p"
        "certificate": {
            "x5u"   : "https://as.example/cert/example2"
        },
        "uri"       : "https://as.example/endpoint/authz/example2"
    }
}

7.2. Interaction Response

The Interaction Response MUST include the following from the Response JSON Section 7.4¶

• iat¶
• nonce¶
• uri¶
• interaction¶

and MAY include the following from the Response JSON Section 7.4¶

• user¶
• wait¶

A non-normative example of an Interaction Response follows:¶

{
    "iat"       : 15790460234,
    "nonce"     : "0d1998d8-fbfa-4879-b942-85a88bff1f3b",
    "uri"       : "https://as.example/endpoint/grant/example4",
    "interaction" : {
        "type"                  : "popup",
        "authorization_uri"     : "https://as.example/popup/example4"
    },
    "user": {
        "exists" : true
    }
}

7.3. Wait Response

The Wait Response MUST include the following from the Response JSON Section 7.4¶

• iat¶
• nonce¶
• uri¶
• wait¶

A non-normative example of Wait Response follows:¶

{
    "iat"       : 15790460234,
    "nonce"     : "0d1998d8-fbfa-4879-b942-85a88bff1f3b",
    "uri"       : "https://as.example/endpoint/grant/example5",
    "wait"      : 300
}

7.4. Response JSON

Details of the JSON document:¶

• iat - the time of the response as a NumericDate.¶
• nonce - the nonce that was included in the Request JSON Section 5.5.¶
• uri - the Grant URI.¶
• wait - a numeric value representing the number of seconds the Client should want before making a Read Grant request to the Grant URI.¶
• expires_in - a numeric value specifying how many seconds until the Grant expires. This attribute is OPTIONAL.¶

7.5. Response Verification

On receipt of a response, the Client MUST verify the following:¶

• TBD¶

8.1. Bearer Token

If the access mechanism is "bearer", then the Client accesses the RS per Section 2.1 of [RFC6750]¶

A non-normative example of the HTTP request headers follows:¶

GET /calendar HTTP/2
Host: calendar.example
Authorization: bearer eyJJ2D6.example.access.token.mZf9pTSpA

10.1. GS Access

The Client authenticates to the GS by passing either a signed header parameter, or a signed message body. The following table shows the verb, uri and token location for each Client request to the GS:¶

{
    "iat"   : 15790460234,
    "jti"   : "f6d72254-4f23-417f-b55e-14ad323b1dc1",
    "uri"   : "https://as.example/endpoint/grant/example6",
    "verb"  : "GET"
}

GET /endpoint/example.grant HTTP/2
Host: as.example
Authorization: jose eyJhbGciOiJIUzI1NiIsIn ...

POST /endpoint HTTP/2
Host: as.example
Content-Type: application/jose
Content-Length: 155

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyzdWIiOiIxMjM0NTY3ODkwIiwibmF
tZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ.SflKxwRJSMeKKF2QT4fwpMe
Jf36POk6yJV_adQssw5c

{
    "alg"   : "ES256",
    "typ"   : "JOSE",
    "kid"   : "12"
}

{
    "alg"   : "ES256",
    "typ"   : "JOSE",
    "jwk"   : {
        "kty"   : "EC",
        "crv"   : "P-256",
        "x"     : "Kgl5DJSgLyV-G32osmLhFKxJ97FoMW0dZVEqDG-Cwo4",
        "y"     : "GsL4mOM4x2e6iON8BHvRDQ6AgXAPnw0m0SfdlREV7i4"
    }
}

10.2. RS Access

In the "jose" mechanism Section 10.2.2, all Client requests to the RS include a proof-of-possession token in the HTTP authorization header. In the "jose+body" mechanism Section 10.2.3, the Client signs the JSON document in the request if the POST or PUT verbs are used, otherwise it is the same as the "jose" mechanism.¶

{
    "alg"   : "ES256",
    "typ"   : "JOSE",
    "x5u"   : "https://as.example/cert/example2"
}

{
    "iat"   : 15790460234,
    "jti"   : "f6d72254-4f23-417f-b55e-14ad323b1dc1",
    "uri"   : "https://calendar.example/calendar",
    "verb"  : "GET",
    "token" : "eyJJ2D6.example.access.token.mZf9pTSpA"
}

GET /calendar HTTP/2
Host: calendar.example
Authorization: jose eyJhbG.example.jose.token.adks

{
    "iat"   : 15790460234,
    "jti"   : "f6d72254-4f23-417f-b55e-14ad323b1dc1",
    "uri"   : "https://calendar.example/calendar",
    "verb"  : "POST",
    "token" : "eyJJ2D6.example.access.token.mZf9pTSpA",
    "payload" : {
        "event" : {
            "title"             : "meeting with joe",
            "start_date_utc"    : "2020-02-21 11:00:00",
            "end_date_utc"      : "2020-02-21 11:00:00"
        }
    }
}

POST /calendar HTTP/2
Host: calendar.example
Content-Type: application/jose
Content-Length: 155

eyJhbGciOi.example.jose+body.adasdQssw5c

10.3. Request Encryption

[Editor: to be fleshed out]¶

The Client encrypts a request when ??? using the GS public key returned as the ??? attribute in GS Options Section 5.9.¶

10.4. Response Signing

[Editor: to be fleshed out]¶

The Client verifies a signed response ??? using the GS public key returned as the ??? attribute in GS Options Section 5.9.¶

10.5. Response Encryption

[Editor: to be fleshed out]¶

The Client decrypts a response when ??? using the private key matching the public key included in the request as the ??? attribute in Section 5.5.¶

A.1. draft-hardt-xauth-protocol-00

• Initial version¶

A.2. draft-hardt-xauth-protocol-01

• text clean up¶
• added OIDC4IA claims¶
• added "jws" method for accessing a resource.¶
• renamed Initiation Request -> Grant Request¶
• renamed Initiation Response -> Interaction Response¶
• renamed Completion Request -> Authorization Request¶
• renamed Completion Response -> Grant Request¶
• renamed completion handle -> authorization handle¶
• added Authentication Request, Authentication Response, authentication handle¶

A.3. draft-hardt-xauth-protocol-02

• major rewrite¶
• handles are now URIs¶
• the collection of claims and authorizations are a Grant¶
• an Authorization is its own type¶
• lots of sequences added¶

A.4. draft-hardt-xauth-protocol-03

• fixed RO definition¶
• improved language in Rationals¶
• added user code interaction method, and aligned qrcode interaction method¶
• added completion_uri for code flows¶

A.5. draft-hardt-xauth-protocol-03

• renamed interaction uris to have purpose specific names¶