| Network Working Group | J. Richer, Ed. |
| Internet-Draft | Bespoke Engineering |
| Intended status: Standards Track | July 25, 2020 |
| Expires: January 26, 2021 |
XYZ: Grant Negotiation Access Protocol
draft-richer-transactional-authz-09
This document defines a mechanism for delegating authorization to a piece of software, and conveying that delegation to the software.
This document is input into the GNAP working group and should be referred to as "XYZ" to differentiate it from other proposals.
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 RFC 2119 RFC 8174 when, and only when, they appear in all capitals, as shown here.
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This protocol allows a piece of software to request delegated authorization to an API, protected by an authorization server usually on behalf of a resource owner. The user operating the software may interact with the authorization server to authenticate, provide consent, and authorize the request.
The Authorization Server (AS) manages the requested delegations. It is defined by its grant endpoint, a single URL that accepts a POST request with a JSON payload. The AS MAY also have other endpoints, including interaction endpoints and user code endpoints, and these are introduced to the RC as needed during the transaction process.
The Resource Client (RC, aka "client") requests tokens from the AS and uses tokens at the RS.
The Resource Server (RS) accepts tokens from the RC and validates them (potentially at the AS).
The Resource Owner (RO) authorizes the request from the RC to the RS, often interactively at the AS.
The Requesting Party (aka "user") operates the RC and may be the same party as the RO.
The RC requests access to an RS, and the AS determines that it needs to interact with the user directly to get the RO's consent:
[[ Editor's note: More sequences and common connections are needed. See Appendix C for more specific examples. ]]
To start a request, the client sends JSON document with an object as its root. Each member of the request object represents a different aspect of the client's request.
A non-normative example of a grant request is below:
{
"resources": [
{
"type": "photo-api",
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
"dolphin-metadata"
],
"key": {
"proof": "jwsd",
"jwk": {
"kty": "RSA",
"e": "AQAB",
"kid": "xyz-1",
"alg": "RS256",
"n": "kOB5rR4Jv0GMeL...."
}
},
"interact": {
"redirect": true,
"callback": {
"uri": "https://client.example.net/return/123455",
"nonce": "LKLTI25DK82FX4T4QFZC"
}
},
"display": {
"name": "My Client Display Name",
"uri": "https://example.net/client"
},
"capabilities": ["ext1", "ext2"],
"subject": {
"sub_ids": ["iss-sub", "email"],
"assertions": ["oidc_id_token"]
}
}
The request MUST be sent as a JSON object in the body of the HTTP POST request with Content-Type application/json, unless otherwise specified by the signature mechanism.
If the client is requesting one or more access tokens for the purpose of accessing an API, the client MUST include a resources element. This element MUST be an array (for a single access token) or an object (for multiple access tokens), as described in the following sections.
When requesting a single access token, the client MUST send a resources element containing a JSON array. The elements of the JSON array represent rights of access that the client is requesting in the access token. The requested access is the sum of all elements within the array. These request elements MAY be sent by value as an object or by reference as a string. A single resources array MAY contain both object and string type resource requests.
The client declares what access it wants to associated with the resulting access token using objects that describe multiple dimensions of access. Each object contains a type property that determines the type of API that the client is calling. The value of this field is under the control of the AS and it MAY determine which other fields allowed in the object. While it is expected that many APIs will have its own properties, a set of common properties are defined here. Specific API implementations SHOULD NOT re-use these fields with different semantics or syntax. [[ Editor's note: this will align with OAuth 2 RAR, but the details of how it aligns are TBD ]].
The following non-normative example shows the use of both common and API-specific elements.
"resources": [
{
"type": "photo-api",
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
{
"type": "financial-transaction",
"actions": [
"withdraw"
],
"identifier": "account-14-32-32-3",
"currency": "USD"
}
]
Instead of sending an object, a client MAY send a string known to the AS or RS representing the access being requested. Each string SHOULD correspond to a specific expanded object representation at the AS. [[ Editor's note: we could describe more about how the expansion would work. For example, expand into an object where the value of the "type" field is the value of the string. Or we could leave it open and flexible, since it's really up to the AS/RS to interpret. ]] This value is opaque to the client and MAY be any valid JSON string, and therefore could include spaces, unicode characters, and properly escaped string sequences.
"resources": [
"read", "dolphin-metadata", "some other thing"
]
A single "resources" array MAY include both object-type and string-type resource items.
"resources": [
{
"type": "photo-api",
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
"read", "dolphin-metadata",
{
"type": "financial-transaction",
"actions": [
"withdraw"
],
"identifier": "account-14-32-32-3",
"currency": "USD"
},
"some other thing"
]
When requesting multiple access tokens, the resources element is a JSON object. The names of the JSON object elements are token identifiers chosen by the client, and MAY be any valid string. The values of the JSON object are JSON arrays representing a single access token request, as specified in requesting a single access token.
The following non-normative example shows a request for two separate access tokens, token1 and token2.
"resources": {
"token1": [
{
"type": "photo-api",
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
"dolphin-metadata"
],
"token2": [
{
"type": "walrus-access",
"actions": [
"foo",
"bar"
],
"locations": [
"https://resource.other/"
],
"datatypes": [
"data",
"pictures",
"walrus whiskers"
]
}
]
}
If the client is requesting information about the current user from the AS, it sends a subject element as a JSON object. This object MAY contain the following fields (or additional fields defined in [[ registry TBD ]]).
"subject": {
"sub_ids": [ "iss-sub", "email" ],
"assertions": [ "oidc-id-token", "saml" ]
}
If the AS knows the identifier for the current user and has permission to do so [[ editor's note: from the user's consent or a policy or ... ]], the AS MAY return the user's information in its response.
The "sub-ids" and "assertions" request fields are independent of each other, and a returned assertion MAY omit a requested subject identifier. [[ Editor's note: we're potentially conflating these two fields in the same structure, so perhaps these should be split. ]]
When sending an initial request to the AS, the client MUST identify itself by including the key field in the request and by signing the request as described in Section 8. This key MAY be sent by value or by reference.
When sent by value, the key MUST be a public key in at least one supported format and MUST contain a proof property that matches the proofing mechanism used in the request. If the key is sent in multiple formats, all the keys MUST be the same. The key presented in this field MUST be the key used to sign the request.
Additional key types are defined in [[ registry TBD ]]. Proof types are defined in a [[ registry TBD ]] and described in Section 8. [[ Editor's note: we will eventually want to have fetchable keys, I would guess. Things like DID for key identification are going to be important. ]]
This non-normative example shows a single key presented in multiple formats using a single proofing mechanism.
"key": {
"proof": "httpsig",
"jwk": {
"kty": "RSA",
"e": "AQAB",
"kid": "xyz-1",
"alg": "RS256",
"n": "kOB5rR4Jv0GMeLaY6_It_r3ORwdf8ci_JtffXyaSx8xY..."
},
"cert": "MIIEHDCCAwSgAwIBAgIBATANBgkqhkiG9w0BAQsFA..."
}
The AS MAY associate policies with the client software identified by this key, such as limiting which resources can be requested and which interaction methods can be used.
If the client has a reference for its key, the client MAY send that reference handle as a string. The format of this string is opaque to the client.
{
"key": "7C7C4AZ9KHRS6X63AJAO"
}
If the key is passed by reference, the proofing mechanism associated with that key reference MUST also be used. If the AS does not recognize the key reference handle, the request MUST be rejected with an error.
If the client identifies its key by reference, the referenced key MAY be a symmetric key known to the AS. The client MUST NOT send a symmetric key by value.
The AS MUST ensure that the key represented by this reference is the same key used to sign the request as described in Section 8.
If the client knows the identity of the current user or one or more identifiers for the user, the client MAY send that information to the AS in the "user" field. The client MAY pass this information by value or by reference.
"user": {
"sub_ids": [ {
"subject_type": "email",
"email": "user@example.com"
} ],
"assertions": {
"oidc_id_token": "eyj..."
}
}
Subject identifiers are hints to the AS in determining the current user and MUST NOT be taken as declarative statements that a particular user is present at the client. Assertions SHOULD be validated by the AS. [[ editor's note: assertion validation is extremely specific to the kind of assertion in place ]]
If the identified user does not match the user present at the AS during an interaction step, the AS SHOULD reject the request. [[ Editor's note: we're potentially conflating identification (sub-ids) and provable presence (assertions and a trusted reference handle) in the same structure, so perhaps these should be split. ]]
Additional user assertion formats are defined in [[ registry TBD -- probably the same registry as requesting formats ]].
If the client has a reference for the current user at this AS, the client MAY pass that reference as a string. The format of this string is opaque to the client.
"user": "XUT2MFM1XBIKJKSDU8QM"
If the AS trusts the client to present user information, it MAY decide, based on its policy, to skip interaction with the user, even if the client provides one or more interaction capabilities.
If the client is capable of driving interaction with the user, the client SHOULD declare the means that it can interact using the "interact" field. This field is a JSON object with keys that declare different interaction capabilities. A client MUST NOT declare an interaction capability it does not support.
The client MAY send multiple capabilities in the same request. There is no preference order specified in this request. An AS MAY respond to any, all, or none of the presented interaction capabilities in a request, depending on its capabilities and what is allowed to fulfill the request.
The following sections detail requests for interaction capabilities. Additional interaction capabilities are defined in [[ a registry TBD ]].
[[ Editor's note: there need to be more examples that knit together the interaction capabilities into common flows, like an authz-code equivalent. But it's important for the protocol design that these are separate pieces to allow such knitting to take place. ]]
"interact": {
"redirect": true,
"user_code": true,
"callback": {
"uri": "https://client.example.net/return/123455",
"nonce": "LKLTI25DK82FX4T4QFZC"
}
}
If the client is capable of directing the user to a URL defined by the AS at runtime, the client indicates this by sending the "redirect" field with the boolean value "true". The means by which the client will activate this URL is out of scope of this specification, but common methods include an HTTP redirect, launching a browser on the user's device, providing a scannable image encoding, and printing out a URL to an interactive console.
"interact": {
"redirect": true
}
If this interaction capability is supported for this client and request, the AS returns a redirect interaction response Section 3.3.1.
If the client can redirect to a shortened URL defined by the AS at runtime, the client indicates this by sending the "redirect" field with the boolean value "true". The means by which the client will activate this URL is out of scope of this specification, but common methods include an HTTP redirect, launching a browser on the user's device, providing a scannable image encoding, and printing out a URL to an interactive console.
"interact": {
"redirect_short": true
}
If this interaction capability is supported for this client and request, the AS returns a redirect interaction response with short URL Section 3.3.2.
[[ Editor's note: I'm not sold on this structure as there's a lot of overlap with the "redirect" capability, so maybe these should merge somehow. Also, I'm not sure if we want additional parameters in here, like a max length that the client can support? These could also be folded into a general "redirect" pattern. ]]
If the client can open a URL associated with an application on the user's device, the client indicates this by sending the "app" field with boolean value "true". The means by which the client determines the application to open with this URL are out of scope of this specification.
"interact": {
"app": true
}
If this interaction capability is supported for this client and request, the AS returns an app interaction response with an app URL payload Section 3.3.3.
[[ Editor's note: this is also similar to the "redirect" above today as most apps use captured URLs, but there seems to be a desire for splitting the web-based interaction and app-based interaction into different URIs. There's also the possibility of wanting more in the payload than can be reasonably put into the URL. ]]
If the client is capable of receiving a callback through the user's browser at the completion of an interaction, the client indicates this by sending the "callback" field. The value of this field is an object containing the following members.
"interact": {
"callback": {
"uri": "https://client.example.net/return/123455",
"nonce": "LKLTI25DK82FX4T4QFZC"
}
}
If this interaction capability is supported for this client and request, the AS returns a nonce for use in validating the callback response. Requests to the callback URI MUST be processed as described in [[ processing interaction callbacks ]], and the AS MUST require presentation of an interaction callback reference as described in Section 4.4.1.
Since the incoming request to the callback URL is from the user's browser, the client MUST require the user to be present on the connection. If used with the "pushback" parameter, the two URLs SHOULD be different as they have different security properties.
Note that the means by which the user arrives at the AS is declared separately from the user's return using this callback mechanism.
If the client is capable of receiving an HTTP message directly from the AS, the client indicates this by sending the "pushback" field. The value of this field is an object containing the following members.
"interact": {
"pushback": {
"uri": "https://client.example.net/push/554321",
"nonce": "82FX4T4QFZCLKLTI25DK"
}
}
If this interaction capability is supported for this client and request, the AS returns a nonce for use in validating the pushback response. Requests to the pushback URI MUST be processed as described in Section 4.4.2, and the AS MUST require presentation of an interaction callback reference as described in [ interaction callback references ].
Since the incoming request to the pushback URL is from the AS and not from the user's browser, the client MUST NOT require the user to be present. If used with the "callback" parameter, the two URLs SHOULD be different as they have different security properties.
Note that the means by which the user arrives at the AS is declared separately from the user's return using this mechanism.
If the client is capable of displaying or otherwise communicating a short, human-entered code to the user, the client indicates this by sending the "user_code" field with the boolean value "true". This code is to be entered at a static URL that does not change at runtime.
"interact": {
"user_code": true
}
If this interaction capability is supported for this client and request, the AS returns a user code and interaction URL as specified in Section 4.2.
Additional interaction capabilities are defined in [[ a registry TBD ]].
[[ Editor's note: we should have guidance in here about how to define other interaction capabilities. There's already interest in defining message-based protocols and challenge-response protocols, for example. ]]
If the client has additional information to display to the user during any interactions at the AS, it MAY send that information in the "display" field. This field is a JSON object that declares information to present to the user during any interactive sequences.
"display": {
"name": "My Client Display Name",
"uri": "https://example.net/client"
}
Additional display fields are defined by [[ a registry TBD. ]]
The AS SHOULD use these values during interaction with the user. The AS MAY restrict display values to specific clients, as identified by their keys.
[[ Editor's note: this might make sense to combine with the "key" field, but some classes of more dynamic client vary those fields separately. We should also consider things like signed statements for client attestation, but that might fit better into a different top-level field instead. ]]
If the client supports extension capabilities, it MAY present them to the AS in the "capabilities" field. This field is an array of strings representing specific extensions and capabilities, as defined by [[ a registry TBD ]].
"capabilities": ["ext1", "ext2"]
If the client has a reference handle from a previously granted request, it MAY send that reference in the "reference" field. This field is a single string.
"existing_grant": "80UPRY5NM33OMUKMKSKU"
The AS MUST dereference the grant associated with the reference and process this request in the context of the referenced one.
[[ Editor's note: this basic capability is to allow for both step-up authorization and downscoped authorization, but by explicitly creating a new request and not modifying an existing one. What's the best guidance for how an AS should process this? ]]
The request object MAY be extended by registering new items in [[ a registry TBD ]]. Extensions SHOULD be orthogonal to other parameters. Extensions MUST document any aspects where the
[[ Editor's note: we should have more guidance and examples on what possible top-level extensions would look like. Things like an OIDC "claims" request or a VC query, for example. ]]
In response to a client's request, the AS responds with a JSON object as the HTTP entity body.
{
"access_token": {
"value": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
"proof": "bearer",
"manage": "https://server.example.com/token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L"
},
"continue": {
"handle": "80UPRY5NM33OMUKMKSKU",
"uri": "https://server.example.com/continue"
},
"subject": {
"sub_ids": [ {
"subject_type": "email",
"email": "user@example.com",
} ]
}
}
If the AS determines that the request can be continued with additional requests, it responds with the "continue" field. This field contains a JSON object with the following properties.
{
"continue": {
"handle": "80UPRY5NM33OMUKMKSKU",
"uri": "https://server.example.com/continue",
"wait": 60
}
}
The client can use the values of this field as described in Section 5.
This field SHOULD be returned when interaction is expected, to allow the client to follow up after interaction has been concluded.
If the AS has successfully granted one or more access tokens, it responds with one of these fields. The AS MUST NOT respond with both fields.
[[ Editor's note: I really don't like the dichotomy between "access_token" and "multiple_access_tokens" and their being mutually exclusive, and I think we should design away from this pattern toward something less error-prone. ]]
If the client has requested a single access token and the AS has granted that access token, the AS responds with the "access_token" field. The value of this field is an object with the following properties.
"access_token": {
"value": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
"proof": "bearer",
"manage": "https://server.example.com/token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L",
"resources": [
{
"type": "photo-api",
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
"read", "dolphin-metadata"
]
}
If the client has requested multiple access tokens and the AS has granted at least one of them, the AS responds with the "multiple_access_tokens" field. The value of this field is a JSON object, and the property names correspond to the token identifiers chosen by the client in the multiple access token request. The values of the properties of this object are access tokens as described in Section 3.2.1.
"multiple_access_tokens": {
"token1": {
"value": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
"proof": "bearer",
"manage": "https://server.example.com/token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L"
},
"token2": {
"value": "UFGLO2FDAFG7VGZZPJ3IZEMN21EVU71FHCARP4J1",
"proof": "bearer"
}
}
Each access token corresponds to the named resources arrays in the client's request. The AS MAY not issue one or more of the requested access tokens. In such cases all of the issued access tokens are included without the omitted token. The multiple access token response MUST be used when multiple access tokens are requested, even if only one access token is issued.
If the client requested a single access token, the AS MUST NOT respond with multiple access tokens.
Each access token MAY have different proofing mechanisms. If used, each access token MUST have different management URIs.
If the client has indicated a capability to interact with the user in its request, and the AS has determined that interaction is both supported and necessary, the AS responds to the client with any of the following values. There is no preference order for interaction capabilities in the response, and it is up to the client to determine which ones to use.
The AS MUST NOT respond with any interaction capability that the client did not indicate in its request.
[[ Editor's note: Currently these are all in the root of the response, but should they be bundled into an "interact" sub-object? This would match the request pattern. ]]
If the client indicates that it can redirect to an arbitrary URL and the AS supports this capability for the client's request, the AS responds with the "interaction_url" field, which is a string containing the URL to direct the user to. This URL MUST be unique for the request and MUST NOT contain any security-sensitive information.
"interaction_url": "https://server.example.com/interact/4CF492MLVMSW9MKMXKHQ"
The client sends the user to the URL to interact with the AS. The client MUST NOT alter the URL in any way. The means for the client to send the user to this URL is out of scope of this specification, but common methods include an HTTP redirect, launching the system browser, displaying a scannable code, or printing out the URL in an interactive console.
[[ Editor's note: should we rename this to "redirect" to match the request? Downside: it conflicts with OAuth 2's "redirect_uri" concept. ]]
If the client indicates that it can redirect to an arbitrary short URL and the AS supports this capability for the client's request, the AS responds with the "short_interaction_url" field, which is a string containing the URL to direct the user to. This URL MUST be unique for the request and MUST NOT contain any security-sensitive information.
"short_interaction_url": "https://srv.ex/MXKHQ"
The client sends the user to the URL to interact with the AS. The client MUST NOT alter the URL in any way. The means for the client to send the user to this URL is out of scope of this specification, but common methods include displaying a scannable code, or printing out the URL in an interactive console.
[[ Editor's note: should we rename this to "short_redirect" to match the request? Downside: it kinda conflicts with OAuth 2's "redirect_uri" concept. This also could be folded into an object for interaction URIs with multiple options instead. ]]
If the client indicates that it can launch an application URL and the AS supports this capability for the client's request, the AS responds with the "app" field, which is a string containing the URL to direct the user to. This URL MUST be unique for the request and MUST NOT contain any security-sensitive information.
"app_url": "https://app.example.com/launch?tx=4CF492MLV"
The client launches the URL as appropriate on its platform, and the means for the client to launch this URL is out of scope of this specification. The client MUST NOT alter the URL in any way. The client MAY attempt to detect if an installed application will service the URL being sent.
[[ Editor's note: This will probably need to be expanded to an object to account for other parameters needed in app2app use cases, like addresses for distributed storage systems, server keys, and the like. Details TBD as people build this out. ]]
If the client indicates that it can receive a post-interaction callback on a URL and the AS supports this capability for the client's request, the AS responds with a "callback_server_nonce" that the client will use in validating the callback as defined in Section 4.4.3.
"callback_server_nonce": "MBDOFXG4Y5CVJCX821LH"
If the AS returns a "callback_server_nonce", the client MUST NOT continue a grant request before it receives the associated interaction reference on the callback URI. If both the "callback" and "pushback" capabilities are available, the client MAY use either value.
[[ Editor's note: should we rename this "callback" and/or put it in an object to match the request? That feels like an overfit to me, though. ]]
If the client indicates that it can receive a post-interaction push on a URL and the AS supports this capability for the client's request, the AS responds with a "pushback_server_nonce" that the client will use in validating the pushback call as defined in Section 4.4.3.
"pushback_server_nonce": "MBDOFXG4Y5CVJCX821LH"
If the AS returns a "pushback_server_nonce", the client MUST NOT continue a grant request before it receives the associated interaction reference on the pushback URI. If both the "callback" and "pushback" capabilities are available, the client MAY use either value.
[[ Editor's note: should we rename this "pushback" and/or put it in an object to match the request? That feels like an overfit to me, though. ]]
If the client indicates that it can display a short user-typable code and the AS supports this capability for the client's request, the AS responds with a "user_code" field. This field is an object that contains the following members.
"user_code": {
"code": "A1BC-3DFF",
"url": "https://srv.ex/device"
}
The client MUST communicate the "code" to the user in some fashion, such as displaying it on a screen or reading it out audibly. The client SHOULD also communicate the URL if possible. As this interaction capability is designed to facilitate interaction via a secondary device, it is not expected that the client redirect the user to the URL. If the client is capable of communicating an arbitrary URL to the user, such as through a scannable code, the client SHOULD use the "redirect" or "short_redirect" capabilities for this purpose.
Extensions to this specification can define new interaction capability responses in [[ a registry TBD ]].
If information about the current user is requested and the AS grants the client access to that data, the AS returns the approved information in the "subject" response field. This field is an object with the following OPTIONAL properties.
"subject": {
"sub_ids": [ {
"subject_type": "email",
"email": "user@example.com",
} ],
"assertions": {
"oidc_id_token": "eyj..."
}
}
Extensions to this specification MAY define additional response properties in [[ a registry TBD ]].
Many parts of the client's request can be passed as either a value or a reference. Some of these references, such as for the client's keys or the resources, can sometimes be managed statically through an admin console or developer portal provided by the AS or RS. If desired, the AS MAY also generate and return some of these references dynamically to the client in its response to facilitate multiple interactions with the same software. The client SHOULD use these references in future requests in lieu of sending the associated data value. These handles are intended to be used on future requests.
Dynamically generated handles are string values that MUST be protected by the client as secrets. Handle values MUST be unguessable and MUST NOT contain any sensitive information. Handle values are opaque to the client. [[ Editor's note: these used to be objects to allow for expansion to future elements, like a management URI or different presentation types or expiration, but those weren't used in practice. Is that desirable anymore or is collapsing them like this the right direction? ]]
All dynamically generated handles are returned as fields in the root JSON object of the response. This specification defines the following dynamic handle returns, additional handles can be defined [[ in a registry TBD ]].
This non-normative example shows two handles along side an issued access token.
{
"user_handle": "XUT2MFM1XBIKJKSDU8QM",
"key_handle": "7C7C4AZ9KHRS6X63AJAO",
"access_token": {
"value": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
"proof": "bearer"
}
}
If the AS determines that the request cannot be issued for any reason, it responds to the RC with an error message.
{
"error": "user_denied"
}
The error code is one of the following, with additional values available in [[ a registry TBD ]]:
[[ Editor's note: I think we will need a more robust error mechanism, and we need to be more clear about what error states are allowed in what circumstances. Additionally, is the "error" parameter exclusive with others in the return? ]]
Extensions to this specification MAY define additional fields for the grant response in [[ a registry TBD ]].
[[ Editor's note: what guidance should we give to designers on this? ]]
If the client indicates that it is capable of driving interaction with the user in its request, and the AS determines that interaction is required and responds to one or more of the client's interaction capabilities, the client SHOULD initiate one of the returned interaction capabilities in the response.
When the RO is interacting with the AS, the AS MAY perform whatever actions it sees fit, including but not limited to:
[[ Editor's note: there are some privacy and security considerations here but for the most part we don't want to be overly prescriptive about the UX, I think. ]]
When the user is directed to the AS through the "interaction_url" or "short_interaction_url" capabilities, the AS can interact with the user through their web browser to authenticate the user as an RO and gather their consent. Note that since the client does not add any parameters to the URL, the AS MUST determine the grant request being referenced from the URL value itself. If the URL cannot be associated with a currently active request, the AS MUST display an error to the user and MUST NOT attempt to redirect the user back to any client.
The interaction URL MUST be reachable from the RO's browser, though note that the RO MAY open the URL on a separate device from the RC itself. The interaction URL MUST be accessible from an HTTP GET request, and MUST be protected by HTTPS or equivalent means.
When the user is directed to the AS through the "user_code" capability, the AS can interact with the user through their web browser to collect the user code, authenticate the user as an RO, and gather their consent. Note that since the URL itself is static, the AS MUST determine the grant request being referenced from the user code value itself. If the user code cannot be associated with a currently active request, the AS MUST display an error to the user and MUST NOT attempt to redirect the user back to any client.
The user code URL MUST be reachable from the RO's browser, though note that the RO MAY open the URL on a separate device from the RC itself. The user code URL MUST be accessible from an HTTP GET request, and MUST be protected by HTTPS or equivalent means.
When the user successfully launches an application through the "app" capability, the AS interacts with the user through that application to authenticate the user as the RO and gather their consent. The details of this interaction are out of scope for this specification.
[[ Editor's note: Should we have anything to say about an app sending information to a back-end to get details on the pending request? ]]
Upon completing an interaction with the user, if either a "callback" or "pushback" capability is available with the current request, the AS MUST follow the appropriate method at the end of interaction to allow the client to continue. If neither capability is available, the AS SHOULD instruct the user to return to their client software upon completion. Note that these steps still take place in most error cases, such as when the user has denied access. This allows the client to potentially recover from the error state without restarting.
[[ Editor's note: there might be some other kind of push-based notification or callback that the client can use, or an out-of-band non-HTTP protocol. The AS would know about this if supported and used, but the guidance here should be written in such a way as to not be too restrictive in the next steps that it can take. Still, it's important that the AS not expect or even allow clients to poll if the client has stated it can take a callback of some form, otherwise that sets up a potential session fixation attack vector that the client is trying to and able to avoid. ]]
The AS MUST calculate a hash value as described in Section 4.4.3. The client will use this value to validate the return call from the AS.
The AS MUST create an interaction reference and associate that reference with the current interaction and the underlying pending request. This value MUST be sufficiently random so as not to be guessable by an attacker.
The AS then MUST send the hash and interaction reference based on the interaction finalization capability as described in the following sections. If both the "callback" and "pushback" capabilities are available for the current request, the AS MUST choose only one. [[ Editor's note: is this restriction necessary? ]]
When using the "callback" interaction capability, the AS signals to the client that interaction is complete and the request can be continued by directing the user (in their browser) back to the client's callback URL sent in the callback request.
The AS secures this callback by adding the hash and interaction reference as query parameters to the client's callback URL.
The means of directing the user to this URL are outside the scope of this specification, but common options include redirecting the user from a web page and launching the system browser with the target URL.
https://client.example.net/return/123455 ?hash=p28jsq0Y2KK3WS__a42tavNC64ldGTBroywsWxT4md_jZQ1R2HZT8BOWYHcLmObM7XHPAdJzTZMtKBsaraJ64A &interact_ref=4IFWWIKYBC2PQ6U56NL1
When receiving the request, the client MUST parse the query parameters to calculate and validate the hash value as described in Section 4.4.3. If the hash validates, the client sends a continuation request to the AS as described in Section 5.1 using the interaction reference value received here.
When using the "pushback" interaction capability, the AS signals to the client that interaction is complete and the request can be continued by sending an HTTP POST request to the client's pushback URL sent in the pushback request.
The entity message body is a JSON object consisting of the following two elements:
POST /push/554321 HTTP/1.1
Host: client.example.net
Content-Type: application/json
{
"hash": "p28jsq0Y2KK3WS__a42tavNC64ldGTBroywsWxT4md_jZQ1R2HZT8BOWYHcLmObM7XHPAdJzTZMtKBsaraJ64A",
"interact_ref": "4IFWWIKYBC2PQ6U56NL1"
}
When receiving the request, the client MUST parse the JSON object and validate the hash value as described in Section 4.4.3. If the hash validates, the client sends a continuation request to the AS as described in Section 5.1 using the interaction reference value received here.
The "hash" parameter in the callback and pushback response ties the front channel response to an ongoing request by using values known only to the parties involved. This prevents several kinds of session fixation attacks against the client.
To calculate the "hash" value, the party doing the calculation first takes the "nonce" value sent by the RC in the interaction section of the initial request, the AS's nonce value, and the "interact_ref" returned in the callback response. For a "callback" return, the AS nonce is the "callback_server_nonce" value in the callback response, while for a "pushback" return the AS nonce is the "pushback_server_nonce" value in the pushback response. These three values are concatenated to each other in this order using a single newline character as a separator between the fields. There is no padding or whitespace before or after any of the lines, and no trailing newline character.
VJLO6A4CAYLBXHTR0KRO MBDOFXG4Y5CVJCX821LH 4IFWWIKYBC2PQ6U56NL1
The party then hashes this string with the appropriate algorithm based on the "hash_method" parameter of the "callback" or "pushback" request. If the "hash_method" value is not present in the RC's request, the algorithm defaults to "sha3". [[ Editor's note: these hash algorithms should be pluggable, and ideally we shouldn't redefine yet another crypto registry for this purpose, but I'm not convinced an appropriate one already exists. ]]
The "sha3" hash method consists of hashing the input string with the 512-bit SHA3 algorithm. The byte array is then encoded using URL Safe Base64 with no padding. The resulting string is the hash value.
p28jsq0Y2KK3WS__a42tavNC64ldGTBroywsWxT4md_jZQ1R2HZT8BOWYHcLmObM7XHPAdJzTZMtKBsaraJ64A
The "sha2" hash method consists of hashing the input string with the 512-bit SHA2 algorithm. The byte array is then encoded using URL Safe Base64 with no padding. The resulting string is the hash value.
62SbcD3Xs7L40rjgALA-ymQujoh2LB2hPJyX9vlcr1H6ecChZ8BNKkG_HrOKP_Bpj84rh4mC9aE9x7HPBFcIHw
If the client receives a continuation element in its response Section 3.1, the client can make an HTTP POST call to the continuation URI with a JSON object. The client MUST send the handle reference from the continuation element in its request as a top-level JSON parameter.
{
"handle": "tghji76ytghj9876tghjko987yh"
}
The client MAY include other parameters as described here or as defined [[ in a registry TBD ]]. [[ Editor's note: We probably want to allow other parameters, like modifying the resources requested or providing more user information. We'll certainly have some kinds of specific challenge-response protocols as there's already been interest in that kind of thing, and the continuation request is the place where that would fit. ]]
If a "wait" parameter was included in the continuation response, the client MUST NOT call the continuation URI prior to waiting the number of seconds indicated. If no "wait" period is indicated, the client SHOULD wait at least 5 seconds [[ Editor's note: what's a reasonable amount of time so as not to DOS the server?? ]].
The response from the AS is a JSON object and MAY contain any of the elements described in Section 3, with some variations:
If the AS determines that the client can make a further continuation request, the AS MUST include a new "continue" response element. The returned handle value MUST NOT be the same as that used to make the continuation request, and the continuation URI MAY remain the same. If the AS does not return a new "continue" response element, the client MUST NOT make an additional continuation request. If a client does so, the AS MUST return an error.
If the AS determines that the client still needs to drive interaction with the user, the AS MAY return appropriate responses for any of the interaction mechanisms the client indicated in its initial request. Unique values such as interaction URIs and nonces SHOULD be re-generated and not re-used.
The client MUST present proof of the same key identified in the initial request by signing the request as described in Section 8.
If the client has received an interaction reference from a "callback" or "pushback" incoming message, the client MUST include the "interaction_ref" in its continuation request. Note that the client validates the hash before making the continuation request, but the client does not send the hash back to the AS.
{
"handle": "tghji76ytghj9876tghjko987yh",
"interact_ref": "4IFWWIKYBC2PQ6U56NL1"
}
A request MAY be continued even after access tokens have been issued, so long as the handle is valid.
If an access token response includes the "manage" parameter as described in Section 3.2.1, the client MAY call this URL to manage the access token with any of the actions defined in the following sections. Other actions are undefined by this specification.
The access token being managed acts as the access element for its own management API. The client MUST present proof of an appropriate key along with the access token.
If the token is sender-constrained (i.e., not a bearer token), it MUST be sent with the appropriate binding for the access token.
If the token is a bearer token, the client MUST present proof of the same key identified in the initial request as described in Section 8.
The AS MUST validate the proof and assure that it is associated with either the token itself or the client the token was issued to, as appropriate for the token's presentation type.
The client makes an HTTP POST to the token management URI, sending the access token in the appropriate header and signing the request with the appropriate key.
POST /token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L HTTP/1.1 Host: server.example.com Authorization: GNAP OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0 Detached-JWS: eyj0....
If the token is validated and the key is appropriate for the request, the AS will invalidate the current access token associated with this URL, if possible, and return a new access token response as described in Section 3.2.1. The value of the access token MUST NOT be the same as the current value of the access token used to access the management API. The response MAY include an updated access token management URL as well, and if so, the client MUST use this new URL to manage the new access token.
{
"access_token": {
"value": "FP6A8H6HY37MH13CK76LBZ6Y1UADG6VEUPEER5H2",
"proof": "bearer",
"manage": "https://server.example.com/token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L",
"resources": [
{
"type": "photo-api",
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
"read", "dolphin-metadata"
]
}
}
The client makes an HTTP DELETE request to the token management URI, signing the request with its key.
DELETE /token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L HTTP/1.1 Host: server.example.com Authorization: GNAP OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0 Detached-JWS: eyj0....
If the token was issued to the client identified by the key, the AS will invalidate the current access token associated with this URL, if possible, and return an HTTP 204 response code.
204 No Content
The method used to send an access token depends on the value of the "proof" parameter in the access token response.
If this value is "bearer", the access token is sent using the HTTP Header method defined in [RFC6750].
Authorization: Bearer OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0
If the "proof" value is any other string, the access token is sent using the HTTP authorization scheme "GNAP" along with a key proof as described in Section 8 for the key bound to the access token. For example, a "jwsd"-bound access token is sent as follows:
Authorization: GNAP OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0 Detached-JWS: eyj0....
[[ Editor's note: I don't actually like the idea of using only one header type for differently-bound access tokens, but instead these values should somehow reflect the key binding types. Maybe there can be multiple fields after the "GNAP" keyword using structured headers? Or a set of derived headers like GNAP-mtls? This might also be better as a separate specification, like OAuth 2. ]]
Any keys presented by the RC to the AS or RS MUST be validated as part of the request in which they are presented. The type of binding used is indicated by the proof parameter of the key section in the initial request Section 2.3. Values defined by this specification are as follows:
Additional values can be defined by [[ a registry TBD ]].
The keys presented by the RC in the requestSection 2 MUST be proved in all continuation requestsSection 5 and token management requests Section 6. The AS MUST validate all keys presented by the RC or referenced in an ongoing transaction at each call.
This method is indicated by jwsd in the proof field. To sign a request, the RC takes the serialized body of the request and signs it using detached JWS [RFC7797]. The header of the JWS MUST contain the kid field of the key bound to this RC for this request. The JWS header MUST contain an alg field appropriate for the key identified by kid and MUST NOT be none.
The RC presents the signature in the Detached-JWS HTTP Header field. [Editor's Note: this is a custom header field, do we need this?]
POST /tx HTTP/1.1
Host: server.example.com
Content-Type: application/json
Detached-JWS: eyJiNjQiOmZhbHNlLCJhbGciOiJSUzI1NiIsImtpZCI6Inh5ei0xIn0.
.Y287HMtaY0EegEjoTd_04a4GC6qV48GgVbGKOhHdJnDtD0VuUlVjLfwne8AuUY3U7e8
9zUWwXLnAYK_BiS84M8EsrFvmv8yDLWzqveeIpcN5_ysveQnYt9Dqi32w6IOtAywkNUD
ZeJEdc3z5s9Ei8qrYFN2fxcu28YS4e8e_cHTK57003WJu-wFn2TJUmAbHuqvUsyTb-nz
YOKxuCKlqQItJF7E-cwSb_xULu-3f77BEU_vGbNYo5ZBa2B7UHO-kWNMSgbW2yeNNLbL
C18Kv80GF22Y7SbZt0e2TwnR2Aa2zksuUbntQ5c7a1-gxtnXzuIKa34OekrnyqE1hmVW
peQ
{
"display": {
"name": "My Client Display Name",
"uri": "https://example.net/client"
},
"resources": [
"dolphin-metadata"
],
"interact": {
"redirect": true,
"callback": {
"uri": "https://client.foo",
"nonce": "VJLO6A4CAYLBXHTR0KRO"
}
},
"key": {
"proof": "jwsd",
"jwk": {
"kty": "RSA",
"e": "AQAB",
"kid": "xyz-1",
"alg": "RS256",
"n": "kOB5rR4Jv0GMeLaY6_It_r3ORwdf8ci_JtffXyaSx8
xYJCNaOKNJn_Oz0YhdHbXTeWO5AoyspDWJbN5w_7bdWDxgpD-y6jnD1u9YhBOCWObNPF
vpkTM8LC7SdXGRKx2k8Me2r_GssYlyRpqvpBlY5-ejCywKRBfctRcnhTTGNztbbDBUyD
SWmFMVCHe5mXT4cL0BwrZC6S-uu-LAx06aKwQOPwYOGOslK8WPm1yGdkaA1uF_FpS6LS
63WYPHi_Ap2B7_8Wbw4ttzbMS_doJvuDagW8A1Ip3fXFAHtRAcKw7rdI4_Xln66hJxFe
kpdfWdiPQddQ6Y1cK2U3obvUg7w"
}
}
}
When the AS receives the Detached-JWS header, it MUST parse its contents as a detached JWS object. The HTTP Body is used as the payload for purposes of validating the JWS, with no transformations.
[[ Editor's note: this is a potentially fragile signature mechanism but it's simple to calculate and useful for body-driven requests, like the client to the AS. We might want to remove this in favor of general-purpose HTTP signing. ]]
This method is indicated by jws in the proof field. To sign a request, the RC takes the serialized body of the request JSON and signs it using JWS [RFC7515]. The header of the JWS MUST contain the kid field of the key bound to this RC during this request. The JWS header MUST contain an alg field appropriate for the key identified by kid and MUST NOT be none.
The RC presents the JWS as the body of the request along with a content type of application/jose. The AS MUST extract the payload of the JWS and treat it as the request body for further processing.
POST /transaction HTTP/1.1 Host: server.example.com Content-Type: application/jose eyJiNjQiOmZhbHNlLCJhbGciOiJSUzI1NiIsImtpZCI6Inh5ei0xIn0.ewogICAgIm NsaWVudCI6IHsKICAgICAgICAibmFtZSI6ICJNeSBDbGllbnQgRGlzcGxheSBOYW1l IiwKICAgICAgICAidXJpIjogImh0dHBzOi8vZXhhbXBsZS5uZXQvY2xpZW50IgogIC AgfSwKICAgICJyZXNvdXJjZXMiOiBbCiAgICAgICAgImRvbHBoaW4tbWV0YWRhdGEi CiAgICBdLAogICAgImludGVyYWN0IjogewogICAgICAgICJyZWRpcmVjdCI6IHRydW UsCiAgICAgICAgImNhbGxiYWNrIjogewogICAgCQkidXJpIjogImh0dHBzOi8vY2xp ZW50LmZvbyIsCiAgICAJCSJub25jZSI6ICJWSkxPNkE0Q0FZTEJYSFRSMEtSTyIKIC AgIAl9CiAgICB9LAogICAgImtleXMiOiB7CgkJInByb29mIjogImp3c2QiLAogICAg ICAgICJqd2tzIjogewogICAgICAgICAgICAia2V5cyI6IFsKICAgICAgICAgICAgIC AgIHsKICAgICAgICAgICAgICAgICAgICAia3R5IjogIlJTQSIsCiAgICAgICAgICAg ICAgICAgICAgImUiOiAiQVFBQiIsCiAgICAgICAgICAgICAgICAgICAgImtpZCI6IC J4eXotMSIsCiAgICAgICAgICAgICAgICAgICAgImFsZyI6ICJSUzI1NiIsCiAgICAg ICAgICAgICAgICAgICAgIm4iOiAia09CNXJSNEp2MEdNZUxhWTZfSXRfcjNPUndkZj hjaV9KdGZmWHlhU3g4eFlKQ0NOYU9LTkpuX096MFloZEhiWFRlV081QW95c3BEV0pi TjV3XzdiZFdEeGdwRC15NmpuRDF1OVloQk9DV09iTlBGdnBrVE04TEM3U2RYR1JLeD JrOE1lMnJfR3NzWWx5UnBxdnBCbFk1LWVqQ3l3S1JCZmN0UmNuaFRUR056dGJiREJV eURTV21GTVZDSGU1bVhUNGNMMEJ3clpDNlMtdXUtTEF4MDZhS3dRT1B3WU9HT3NsSz hXUG0xeUdka2FBMXVGX0ZwUzZMUzYzV1lQSGlfQXAyQjdfOFdidzR0dHpiTVNfZG9K dnVEYWdXOEExSXAzZlhGQUh0UkFjS3c3cmRJNF9YbG42NmhKeEZla3BkZldkaVBRZG RRNlkxY0syVTNvYnZVZzd3IgogICAgICAgICAgICAgICAgfQogICAgICAgICAgICBd CiAgICAgICAgfQogICAgfQp9.Y287HMtaY0EegEjoTd_04a4GC6qV48GgVbGKOhHdJ nDtD0VuUlVjLfwne8AuUY3U7e89zUWwXLnAYK_BiS84M8EsrFvmv8yDLWzqveeIpcN 5_ysveQnYt9Dqi32w6IOtAywkNUDZeJEdc3z5s9Ei8qrYFN2fxcu28YS4e8e_cHTK5 7003WJu-wFn2TJUmAbHuqvUsyTb-nzYOKxuCKlqQItJF7E-cwSb_xULu-3f77BEU_v GbNYo5ZBa2B7UHO-kWNMSgbW2yeNNLbLC18Kv80GF22Y7SbZt0e2TwnR2Aa2zksuUb ntQ5c7a1-gxtnXzuIKa34OekrnyqE1hmVWpeQ
[[ Editor's note: A downside to this method is that it requires the content type to be something other than application/json, and it doesn't work against an RS without additional profiling since it requires things to be sent in the body. Additionally it is potentially fragile like a detached JWS since a multi-tier system could parse the payload and pass it downstream with potential transformations. ]]
This method is indicated by mtls in the proof field. The RC presents its client certificate during TLS negotiation with the server (either AS or RS). The AS or RS takes the thumbprint of the client certificate presented during mutual TLS negotiation and compares that thumbprint to the thumbprint presented by the RC application as described in [RFC8705] section 3.
Client?AS
POST /transaction HTTP/1.1
Host: server.example.com
Content-Type: application/json
SSL_CLIENT_CERT: MIIEHDCCAwSgAwIBAgIBATANBgkqhkiG9w0BAQsFADCBmjE3MDUGA1UEAwwuQmVz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{
"client": {
"name": "My Client Display Name",
"uri": "https://example.net/client"
},
"resources": [
"dolphin-metadata"
],
"interact": {
"redirect": true,
"callback": {
"uri": "https://client.foo",
"nonce": "VJLO6A4CAYLBXHTR0KRO"
}
},
"key": {
"proof": "mtls",
"cert": "MIIEHDCCAwSgAwIBAgIBATANBgkqhkiG9w0BAQsFADCBmjE3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"
}
}
This method is indicated by dpop in the proof field. The RC creates a DPoP signature header as described in [I-D.ietf-oauth-dpop] section 2.
POST /transaction HTTP/1.1
Host: server.example.com
Content-Type: application/json
DPoP: eyJ0eXAiOiJkcG9wK2p3dCIsImFsZyI6IlJTMjU2IiwiandrIjp7Imt0eSI6Il
JTQSIsImUiOiJBUUFCIiwia2lkIjoieHl6LWNsaWVudCIsImFsZyI6IlJTMjU2Iiwibi
I6Inp3Q1RfM2J4LWdsYmJIcmhlWXBZcFJXaVk5SS1uRWFNUnBablJySWpDczZiX2VteV
RrQmtEREVqU3lzaTM4T0M3M2hqMS1XZ3hjUGRLTkdaeUlvSDNRWmVuMU1LeXloUXBMSk
cxLW9MTkxxbTdwWFh0ZFl6U2RDOU8zLW9peXk4eWtPNFlVeU5aclJSZlBjaWhkUUNiT1
9PQzhRdWdtZzlyZ05ET1NxcHBkYU5lYXMxb3Y5UHhZdnhxcnoxLThIYTdna0QwMFlFQ1
hIYUIwNXVNYVVhZEhxLU9fV0l2WVhpY2c2STVqNlM0NFZOVTY1VkJ3dS1BbHluVHhRZE
1BV1AzYll4VlZ5NnAzLTdlVEpva3ZqWVRGcWdEVkRaOGxVWGJyNXlDVG5SaG5oSmd2Zj
NWakRfbWFsTmU4LXRPcUs1T1NEbEhUeTZnRDlOcWRHQ20tUG0zUSJ9fQ.eyJodHRwX21
ldGhvZCI6IlBPU1QiLCJodHRwX3VyaSI6Imh0dHA6XC9cL2hvc3QuZG9ja2VyLmludGV
ybmFsOjk4MzRcL2FwaVwvYXNcL3RyYW5zYWN0aW9uIiwiaWF0IjoxNTcyNjQyNjEzLCJ
qdGkiOiJIam9IcmpnbTJ5QjR4N2pBNXl5RyJ9.aUhftvfw2NoW3M7durkopReTvONng1
fOzbWjAlKNSLL0qIwDgfG39XUyNvwQ23OBIwe6IuvTQ2UBBPklPAfJhDTKd8KHEAfidN
B-LzUOzhDetLg30yLFzIpcEBMLCjb0TEsmXadvxuNkEzFRL-Q-QCg0AXSF1h57eAqZV8
SYF4CQK9OUV6fIWwxLDd3cVTx83MgyCNnvFlG_HDyim1Xx-rxV4ePd1vgDeRubFb6QWj
iKEO7vj1APv32dsux67gZYiUpjm0wEZprjlG0a07R984KLeK1XPjXgViEwEdlirUmpVy
T9tyEYqGrTfm5uautELgMls9sgSyE929woZ59elg
{
"client": {
"name": "My Client Display Name",
"uri": "https://example.net/client"
},
"resources": [
"dolphin-metadata"
],
"interact": {
"redirect": true,
"callback": {
"uri": "https://client.foo",
"nonce": "VJLO6A4CAYLBXHTR0KRO"
}
},
"key": {
"proof": "dpop",
"jwk": {
"kty": "RSA",
"e": "AQAB",
"kid": "xyz-1",
"alg": "RS256",
"n": "kOB5rR4Jv0GMeLaY6_It_r3ORwdf8ci_JtffXyaSx8xYJCCNaOKNJn_Oz0YhdHbXTeWO5AoyspDWJbN5w_7bdWDxgpD-y6jnD1u9YhBOCWObNPFvpkTM8LC7SdXGRKx2k8Me2r_GssYlyRpqvpBlY5-ejCywKRBfctRcnhTTGNztbbDBUyDSWmFMVCHe5mXT4cL0BwrZC6S-uu-LAx06aKwQOPwYOGOslK8WPm1yGdkaA1uF_FpS6LS63WYPHi_Ap2B7_8Wbw4ttzbMS_doJvuDagW8A1Ip3fXFAHtRAcKw7rdI4_Xln66hJxFekpdfWdiPQddQ6Y1cK2U3obvUg7w"
}
}
}
[[ Editor's note: this method requires duplication of the key in the header and the request body, which is redundant and potentially awkward. ]]
This method is indicated by httpsig in the proof field. The RC creates an HTTP Signature header as described in [I-D.ietf-httpbis-message-signatures] section 4. The RC MUST calculate and present the Digest header as defined in [RFC3230].
POST /transaction HTTP/1.1
Host: server.example.com
Content-Type: application/json
Content-Length: 716
Signature: keyId="xyz-client", algorithm="rsa-sha256",
headers="(request-target) digest content-length",
signature="TkehmgK7GD/z4jGkmcHS67cjVRgm3zVQNlNrrXW32Wv7d
u0VNEIVI/dMhe0WlHC93NP3ms91i2WOW5r5B6qow6TNx/82/6W84p5jqF
YuYfTkKYZ69GbfqXkYV9gaT++dl5kvZQjVk+KZT1dzpAzv8hdk9nO87Xi
rj7qe2mdAGE1LLc3YvXwNxuCQh82sa5rXHqtNT1077fiDvSVYeced0UEm
rWwErVgr7sijtbTohC4FJLuJ0nG/KJUcIG/FTchW9rd6dHoBnY43+3Dzj
CIthXpdH5u4VX3TBe6GJDO6Mkzc6vB+67OWzPwhYTplUiFFV6UZCsDEeu
Sa/Ue1yLEAMg=="]}
Digest: SHA=oZz2O3kg5SEFAhmr0xEBbc4jEfo=
{
"client": {
"name": "My Client Display Name",
"uri": "https://example.net/client"
},
"resources": [
"dolphin-metadata"
],
"interact": {
"redirect": true,
"callback": {
"uri": "https://client.foo",
"nonce": "VJLO6A4CAYLBXHTR0KRO"
}
},
"key": {
"proof": "httpsig",
"jwk": {
"kty": "RSA",
"e": "AQAB",
"kid": "xyz-1",
"alg": "RS256",
"n": "kOB5rR4Jv0GMeLaY6_It_r3ORwdf8ci_J
tffXyaSx8xYJCCNaOKNJn_Oz0YhdHbXTeWO5AoyspDWJbN5w_7bdWDxgpD-
y6jnD1u9YhBOCWObNPFvpkTM8LC7SdXGRKx2k8Me2r_GssYlyRpqvpBlY5-
ejCywKRBfctRcnhTTGNztbbDBUyDSWmFMVCHe5mXT4cL0BwrZC6S-uu-LAx
06aKwQOPwYOGOslK8WPm1yGdkaA1uF_FpS6LS63WYPHi_Ap2B7_8Wbw4ttz
bMS_doJvuDagW8A1Ip3fXFAHtRAcKw7rdI4_Xln66hJxFekpdfWdiPQddQ6
Y1cK2U3obvUg7w"
}
}
}
This method is indicated by oauthpop in the proof field. The RC creates an HTTP Authorization PoP header as described in [I-D.ietf-oauth-signed-http-request] section 4, with the following additional requirements:
POST /transaction HTTP/1.1
Host: server.example.com
Content-Type: application/json
PoP: eyJhbGciOiJSUzI1NiIsImp3ayI6eyJrdHkiOiJSU0EiLCJlIjoi
QVFBQiIsImtpZCI6Inh5ei1jbGllbnQiLCJhbGciOiJSUzI1NiIsIm4iO
iJ6d0NUXzNieC1nbGJiSHJoZVlwWXBSV2lZOUktbkVhTVJwWm5ScklqQ3
M2Yl9lbXlUa0JrRERFalN5c2kzOE9DNzNoajEtV2d4Y1BkS05HWnlJb0g
zUVplbjFNS3l5aFFwTEpHMS1vTE5McW03cFhYdGRZelNkQzlPMy1vaXl5
OHlrTzRZVXlOWnJSUmZQY2loZFFDYk9fT0M4UXVnbWc5cmdORE9TcXBwZ
GFOZWFzMW92OVB4WXZ4cXJ6MS04SGE3Z2tEMDBZRUNYSGFCMDV1TWFVYW
RIcS1PX1dJdllYaWNnNkk1ajZTNDRWTlU2NVZCd3UtQWx5blR4UWRNQVd
QM2JZeFZWeTZwMy03ZVRKb2t2allURnFnRFZEWjhsVVhicjV5Q1RuUmhu
aEpndmYzVmpEX21hbE5lOC10T3FLNU9TRGxIVHk2Z0Q5TnFkR0NtLVBtM
1EifX0.eyJwIjoiXC9hcGlcL2FzXC90cmFuc2FjdGlvbiIsImIiOiJxa0
lPYkdOeERhZVBTZnc3NnFjamtqSXNFRmxDb3g5bTU5NFM0M0RkU0xBIiw
idSI6Imhvc3QuZG9ja2VyLmludGVybmFsIiwiaCI6W1siQWNjZXB0Iiwi
Q29udGVudC1UeXBlIiwiQ29udGVudC1MZW5ndGgiXSwiVjQ2OUhFWGx6S
k9kQTZmQU5oMmpKdFhTd3pjSGRqMUloOGk5M0h3bEVHYyJdLCJtIjoiUE
9TVCIsInRzIjoxNTcyNjQyNjEwfQ.xyQ47qy8bu4fyK1T3Ru1Sway8wp6
5rfAKnTQQU92AUUU07I2iKoBL2tipBcNCC5zLH5j_WUyjlN15oi_lLHym
fPdzihtt8_Jibjfjib5J15UlifakjQ0rHX04tPal9PvcjwnyZHFcKn-So
Y3wsARn-gGwxpzbsPhiKQP70d2eG0CYQMA6rTLslT7GgdQheelhVFW29i
27NcvqtkJmiAG6Swrq4uUgCY3zRotROkJ13qo86t2DXklV-eES4-2dCxf
cWFkzBAr6oC4Qp7HnY_5UT6IWkRJt3efwYprWcYouOVjtRan3kEtWkaWr
G0J4bPVnTI5St9hJYvvh7FE8JirIg
{
"client": {
"name": "My Client Display Name",
"uri": "https://example.net/client"
},
"resources": [
"dolphin-metadata"
],
"interact": {
"redirect": true,
"callback": {
"uri": "https://client.foo",
"nonce": "VJLO6A4CAYLBXHTR0KRO"
}
},
"key": {
"proof": "oauthpop",
"jwk": {
"kty": "RSA",
"e": "AQAB",
"kid": "xyz-1",
"alg": "RS256",
"n": "kOB5rR4Jv0GMeLaY6_It_r3ORwdf8ci_J
tffXyaSx8xYJCCNaOKNJn_Oz0YhdHbXTeWO5AoyspDWJbN5w_7bdWDxgpD-
y6jnD1u9YhBOCWObNPFvpkTM8LC7SdXGRKx2k8Me2r_GssYlyRpqvpBlY5-
ejCywKRBfctRcnhTTGNztbbDBUyDSWmFMVCHe5mXT4cL0BwrZC6S-uu-LAx
06aKwQOPwYOGOslK8WPm1yGdkaA1uF_FpS6LS63WYPHi_Ap2B7_8Wbw4ttz
bMS_doJvuDagW8A1Ip3fXFAHtRAcKw7rdI4_Xln66hJxFekpdfWdiPQddQ6
Y1cK2U3obvUg7w"
}
}
}
By design, the protocol minimizes the need for any pre-flight discovery. To begin a request, the RC only needs to know the endpoint of the AS and which keys it will use to sign the request. Everything else can be negotiated dynamically in the course of the protocol.
However, the AS can have limits on its allowed functionality. If the RC wants to optimize its calls to the AS before making a request, it MAY send an HTTP OPTIONS request to the transaction endpoint to retrieve the server's discovery information. The AS MUST respond with a JSON document containing the following information:
The information returned from this method is for optimization purposes only. The AS MAY deny any request, or any portion of a request, even if it lists a capability as supported. For example, a given client can be registered with the mtls key proofing mechanism, but the AS also returns other proofing methods, then the AS will deny a request from that client using a different proofing mechanism.
In some deployments, a resource server will need to be able to call the AS for a number of functions.
[[ Editor's note: This section is for discussion of possible advanced functionality. It seems like it should be a separate document or set of documents, and it's not even close to being well-baked. This also adds additional endpoints to the AS, as this is separate from the token request process, and therefore would require RS-facing discovery or configuration information to make it work. Also-also, it does presume the RS can sign requests in the same way that a client does, but hopefully we can be more consistent with this than RFC7662 was able to do. ]]
When the RS receives an access token, it can call the introspection endpoint at the AS to get token information. [[ Editor's note: this isn't super different from the token management URIs, but the RS has no way to get that URI, and it's bound to different keys. ]]
The RS signs the request with its own key and sends the access token as the body of the request.
POST /introspect HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"access_token": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
}
The AS responds with a data structure describing the token's current state and any information the RS would need to validate the token's presentation, such as its intended proofing mechanism and key material.
Content-type: application/json
{
"active": true,
"resources": [
"dolphin-metadata", "some other thing"
],
"resources": [
"dolphin-metadata", "some other thing"
],
"proof": "httpsig",
"key": {
"proof": "jwsd",
"jwk": {
"kty": "RSA",
"e": "AQAB",
"kid": "xyz-1",
"alg": "RS256",
"n": "kOB5rR4Jv0GMeL...."
}
}
}
If the RS needs to derive a token from one presented to it, it can request one from the AS by making a token request as described in Section 2 and presenting the existing access token's value in the "existing_access_token" field.
The RS MUST identify itself with its own key and sign the request.
[[ Editor's note: this is similar to but based on the access token and not the grant. The fact that the keys presented are not the ones used for the access token should indicate that it's a different party and a different kind of request. ]]
POST /tx HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"resources": [
{
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
"dolphin-metadata"
],
"key": "7C7C4AZ9KHRS6X63AJAO",
"existing_access_token": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0"
}
The AS responds with a token as described in Section 3.
If the RS needs to, it can post a set of resources as described in Section 2.1.1 to the AS's resource registration endpoint.
The RS MUST identify itself with its own key and sign the request.
POST /resource HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"resources": [
{
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
"dolphin-metadata"
],
"key": "7C7C4AZ9KHRS6X63AJAO"
}
The AS responds with a handle appropriate to represent the resources list that the RS presented.
Content-type: application/json
{
"resource_handle": "FWWIKYBQ6U56NL1"
}
The RS MAY make this handle available as part of a response to a client or as documentation to developers.
[[ Editor's note: It's not an exact match here because the "resource_handle" returned now represents a collection of objects instead of a single one. Perhaps we should let this return a list of strings instead? Or use a different syntax than the resource request? Also, this borrows heavily from UMA 2's "distributed authorization" model and, like UMA, might be better suited to an extension than the core protocol. ]]
If the client calls an RS without an access token, or with an invalid access token, the RS MAY respond to the client with an authentication header indicating that GNAP. The address of the GNAP endpoint MUST be sent in the "as_uri" parameter. The RS MAY additionally return a resource reference that the client MAY use in its resource request. This resource reference handle SHOULD be sufficient for at least the action the client was attempting to take at the RS. The RS MAY use the dynamic resource handle request to register a new resource handle, or use a handle that has been pre-configured to represent what the AS is protecting. The content of this handle is opaque to the RS and the client.
WWW-Authenticate: GNAP as_uri=http://server.example/transaction,resource=FWWIKYBQ6U56NL1
The client then makes a call to the "as_uri" as described in Section 2, with the value of "resource" as one of the members of a "resources" array Section 2.1.1. The client MAY request additional resources and other information, and MAY request multiple access tokens.
[[ Editor's note: this borrows heavily from UMA 2's "distributed authorization" model and, like UMA, might be better suited to an extension than the core protocol. ]]
The author would like to thank the feedback of the GNAP working group.
[[ TBD: There are a lot of items in the document that are expandable through the use of value registries. ]]
[[ TBD: There are a lot of security considerations to add. ]]
All requests have to be over TLS or equivalent. Many handles act as shared secrets, though they can be combined with a requirement to provide proof of a key as well.
[[ TBD: There are a lot of privacy considerations to add. ]]
Handles are passed between parties and therefore should not contain any private data.
When user information is passed to the client, the AS needs to make sure that it has the permission to do so.
| [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, DOI 10.17487/RFC7525, May 2015. |
| [I-D.ietf-httpbis-message-signatures] | Backman, A., Richer, J. and M. Sporny, "Signing HTTP Messages", Internet-Draft draft-ietf-httpbis-message-signatures-00, April 2020. |
| [I-D.ietf-oauth-dpop] | Fett, D., Campbell, B., Bradley, J., Lodderstedt, T., Jones, M. and D. Waite, "OAuth 2.0 Demonstration of Proof-of-Possession at the Application Layer (DPoP)", Internet-Draft draft-ietf-oauth-dpop-01, May 2020. |
| [I-D.ietf-oauth-signed-http-request] | Richer, J., Bradley, J. and H. Tschofenig, "A Method for Signing HTTP Requests for OAuth", Internet-Draft draft-ietf-oauth-signed-http-request-03, August 2016. |
| [I-D.ietf-secevent-subject-identifiers] | Backman, A. and M. Scurtescu, "Subject Identifiers for Security Event Tokens", Internet-Draft draft-ietf-secevent-subject-identifiers-05, July 2019. |
| [RFC2119] | Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997. |
| [RFC3230] | Mogul, J. and A. Van Hoff, "Instance Digests in HTTP", RFC 3230, DOI 10.17487/RFC3230, January 2002. |
| [RFC6750] | Jones, M. and D. Hardt, "The OAuth 2.0 Authorization Framework: Bearer Token Usage", RFC 6750, DOI 10.17487/RFC6750, October 2012. |
| [RFC7515] | Jones, M., Bradley, J. and N. Sakimura, "JSON Web Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May 2015. |
| [RFC7797] | Jones, M., "JSON Web Signature (JWS) Unencoded Payload Option", RFC 7797, DOI 10.17487/RFC7797, February 2016. |
| [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., "The JavaScript Object Notation (JSON) Data Interchange Format", STD 90, RFC 8259, DOI 10.17487/RFC8259, December 2017. |
| [RFC8705] | Campbell, B., Bradley, J., Sakimura, N. and T. Lodderstedt, "OAuth 2.0 Mutual-TLS Client Authentication and Certificate-Bound Access Tokens", RFC 8705, DOI 10.17487/RFC8705, February 2020. |
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While different implementations of this protocol will have different realizations of all the components and artifacts enumerated here, the nature of the protocol implies some common structures and elements for certain components. This appendix seeks to enumerate those common elements.
TBD: Client has keys, allowed requested resources, identifier(s), allowed requested subjects, allowed
TBD: AS has "grant endpoint", interaction endpoints, store of trusted client keys, policies
TBD: Token has RO, user, client, resource list, RS list,
The protocol defined in this specification provides a number of features that can be combined to solve many different kinds of authentication scenarios. This section seeks to show examples of how the protocol would be applied for different situations.
Some longer fields, particularly cryptographic information, have been truncated for display purposes in these examples.
In this scenario, the user is the RO and has access to a web browser, and the client can take front-channel callbacks on the same device as the user. This combination is analogous to the OAuth 2 Authorization Code grant type.
The client initiates the request to the AS. Here the client identifies itself using its public key.
POST /tx HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"resources": [
{
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
}
],
"key": {
"proof": "jwsd",
"jwk": {
"kty": "RSA",
"e": "AQAB",
"kid": "xyz-1",
"alg": "RS256",
"n": "kOB5rR4Jv0GMeLaY6_It_r3ORwdf8ci_JtffXyaSx8xY..."
}
},
"interact": {
"redirect": true,
"callback": {
"uri": "https://client.example.net/return/123455",
"nonce": "LKLTI25DK82FX4T4QFZC"
}
}
}
The AS processes the request and determines that the RO needs to interact. The AS returns the following response giving the client the information it needs to connect. The AS has also indicated to the client that it can use the given key handle to identify itself in future calls.
Content-type: application/json
{
"interaction_url": "https://server.example.com/interact/4CF492MLVMSW9MKMXKHQ",
"server_nonce": "MBDOFXG4Y5CVJCX821LH",
"continue": {
"handle": "80UPRY5NM33OMUKMKSKU",
"uri": "https://server.example.com/continue"
},
"key_handle": "7C7C4AZ9KHRS6X63AJAO"
}
The client saves the response and redirects the user to the interaction_url by sending the following HTTP message to the user's browser.
HTTP 302 Found Location: https://server.example.com/interact/4CF492MLVMSW9MKMXKHQ
The user's browser fetches the AS's interaction URL. The user logs in, is identified as the RO for the resource being requested, and approves the request. Since the AS has a callback parameter, the AS generates the interaction reference, calculates the hash, and redirects the user back to the client with these additional values added as query parameters.
HTTP 302 Found Location: https://client.example.net/return/123455 ?hash=p28jsq0Y2KK3WS__a42tavNC64ldGTBroywsWxT4md_jZQ1R2HZT8BOWYHcLmObM7XHPAdJzTZMtKBsaraJ64A &interact_ref=4IFWWIKYBC2PQ6U56NL1
The client receives this request from the user's browser. The client ensures that this is the same user that was sent out by validating session information and retrieves the stored pending request. The client uses the values in this to validate the hash parameter. The client then calls the continuation URL and presents the handle and interaction reference in the request body. The client signs the request as above.
POST /continue HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"handle": "80UPRY5NM33OMUKMKSKU",
"interact_ref": "4IFWWIKYBC2PQ6U56NL1"
}
The AS retrieves the pending request based on the handle and issues a bearer access token and returns this to the client.
Content-type: application/json
{
"access_token": {
"value": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
"proof": "bearer",
"manage": "https://server.example.com/token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L",
"resources": [{
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
}]
},
"continue": {
"handle": "80UPRY5NM33OMUKMKSKU",
"uri": "https://server.example.com/continue"
}
}
In this scenario, the user does not have access to a web browser on the device and must use a secondary device to interact with the AS. The client can display a user code or a printable QR code. The client prefers a short URL if one is available.
The client initiates the request to the AS.
POST /tx HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"resources": [
"dolphin-metadata", "some other thing"
],
"key": "7C7C4AZ9KHRS6X63AJAO",
"interact": {
"redirect": true,
"short_redirect": true,
"user_code": true
}
}
The AS processes this and determines that the RO needs to interact. The AS supports both long and short redirect URIs for interaction, so it includes both. Since there is no "callback" the AS does not include a nonce, but does include a "wait" parameter on the continuation section because it expects the client to poll for results.
Content-type: application/json
{
"interaction_url": "https://server.example.com/interact/4CF492MLVMSW9MKMXKHQ",
"short_interaction_url": "https://srv.ex/MXKHQ",
"user_code": {
"code": "A1BC-3DFF",
"url": "https://srv.ex/device"
},
"continue": {
"handle": "80UPRY5NM33OMUKMKSKU",
"uri": "https://server.example.com/continue",
"wait": 60
}
}
The client saves the response and displays the user code visually on its screen along with the static device URL. The client also displays the short interaction URL as a QR code to be scanned. The client ignores the longer interaction URL because both the long and short ones
If the user scans the code, they are taken to the interaction endpoint and the AS looks up the current pending request based on the incoming URL. If the user instead goes to the static page and enters the code manually, the AS looks up the current pending request based on the value of the user code. In both cases, the user logs in, is identified as the RO for the resource being requested, and approves the request. Once the request has been approved, the AS displays to the user a message to return to their device.
Meanwhile, the client periodically polls the AS every 60 seconds at the continuation URL.
POST /continue HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"handle": "80UPRY5NM33OMUKMKSKU"
}
The AS retrieves the pending request based on the handle and determines that it has not yet been authorized. The AS indicates to the client that no access token has yet been issued but it can continue to call after another 60 second timeout.
Content-type: application/json
{
"continue": {
"handle": "BI9QNW6V9W3XFJK4R02D",
"uri": "https://server.example.com/continue",
"wait": 60
}
}
Note that the continuation handle has been rotated since it was used by the client to make this call. The client polls the continuation URL after a 60 second timeout using the new handle.
POST /continue HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"handle": "BI9QNW6V9W3XFJK4R02D"
}
The AS retrieves the pending request based on the handle and determines that it has been approved and it issues an access token.
Content-type: application/json
{
"access_token": {
"value": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
"proof": "bearer",
"manage": "https://server.example.com/token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L",
"resources": [
"dolphin-metadata", "some other thing"
]
}
}
In this scenario, the client is requesting access on its own behalf, with no user to interact with.
The client creates a request to the AS, identifying itself with its public key and using MTLS to make the request.
POST /tx HTTP/1.1
Host: server.example.com
Content-type: application/json
{
"resources": [
"backend service", "nightly-routine-3"
],
"key": {
"proof": "mtls",
"cert#S256": "bwcK0esc3ACC3DB2Y5_lESsXE8o9ltc05O89jdN-dg2"
}
}
The AS processes this and determines that the client can ask for the requested resources and issues an access token.
Content-type: application/json
{
"access_token": {
"value": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
"proof": "bearer",
"manage": "https://server.example.com/token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L",
"resources": [
"backend service", "nightly-routine-3"
]
}
}
In this scenario, the client is requesting on behalf of a specific RO, but has no way to interact with the user. The AS can asynchronously reach out to the RO for approval in this scenario.
The client starts the request at the AS by requesting a set of resources. The client also identifies a particular user.
POST /tx HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"resources": [
{
"type": "photo-api",
"actions": [
"read",
"write",
"dolphin"
],
"locations": [
"https://server.example.net/",
"https://resource.local/other"
],
"datatypes": [
"metadata",
"images"
]
},
"read", "dolphin-metadata",
{
"type": "financial-transaction",
"actions": [
"withdraw"
],
"identifier": "account-14-32-32-3",
"currency": "USD"
},
"some other thing"
],
"key": "7C7C4AZ9KHRS6X63AJAO",
"user": {
"sub-ids": [ {
"subject_type": "email",
"email": "user@example.com"
} ]
}
}
The AS processes this and determines that the RO needs to interact. The AS determines that it can reach the identified user asynchronously and that the identified user does have the ability to approve this request. The AS indicates to the client that it can poll for continuation.
Content-type: application/json
{
"continue": {
"handle": "80UPRY5NM33OMUKMKSKU",
"uri": "https://server.example.com/continue",
"wait": 60
}
}
The AS reaches out to the RO and prompts them for consent. In this example, the AS has an application that it can push notifications in to for the specified account.
Meanwhile, the client periodically polls the AS every 60 seconds at the continuation URL.
POST /continue HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"handle": "80UPRY5NM33OMUKMKSKU"
}
The AS retrieves the pending request based on the handle and determines that it has not yet been authorized. The AS indicates to the client that no access token has yet been issued but it can continue to call after another 60 second timeout.
Content-type: application/json
{
"continue": {
"handle": "BI9QNW6V9W3XFJK4R02D",
"uri": "https://server.example.com/continue",
"wait": 60
}
}
Note that the continuation handle has been rotated since it was used by the client to make this call. The client polls the continuation URL after a 60 second timeout using the new handle.
POST /continue HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"handle": "BI9QNW6V9W3XFJK4R02D"
}
The AS retrieves the pending request based on the handle and determines that it has been approved and it issues an access token.
Content-type: application/json
{
"access_token": {
"value": "OS9M2PMHKUR64TB8N6BW7OZB8CDFONP219RP1LT0",
"proof": "bearer",
"manage": "https://server.example.com/token/PRY5NM33OM4TB8N6BW7OZB8CDFONP219RP1L",
"resources": [
"dolphin-metadata", "some other thing"
]
}
}
In this scenario, the client developer has a client_id and set of scope values from their OAuth 2 system and wants to apply them to the new protocol. Traditionally, the OAuth 2 client developer would put their client_id and scope values as parameters into a redirect request to the authorization endpoint.
HTTP 302 Found Location: https://server.example.com/authorize ?client_id=7C7C4AZ9KHRS6X63AJAO &scope=read%20write%20dolphin &redirect_uri=https://client.example.net/return &response_type=code &state=123455
Now the developer wants to make an analogous request to the AS using the new protocol. To do so, the client makes an HTTP POST and places the OAuth 2 values in the appropriate places.
POST /tx HTTP/1.1
Host: server.example.com
Content-type: application/json
Detached-JWS: ejy0...
{
"resources": [
"read", "write", "dolphin"
],
"key": "7C7C4AZ9KHRS6X63AJAO",
"interact": {
"redirect": true,
"callback": {
"uri": "https://client.example.net/return?state=123455",
"nonce": "LKLTI25DK82FX4T4QFZC"
}
}
}
The client_id can be used to identify the client's keys that it uses for authentication, the scopes represent resources that the client is requesting, and the redirect_uri and state value are combined into a callback URI that can be unique per request. The client additionally creates a nonce to protect the callback, separate from the state parameter that it has added to its return URL.
From here, the protocol continues as above.