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Section 2.2 is currently called: Then the text continues with: This means that this section is currently restricted to the RO. Since this call is restricted to the RO, the title of this section should be changed into: Requesting RO Information. In addition, the reason(s) for requesting such information is not mentioned and should be explained. As a side-consequence, a user has no on-line means to know which personal data the AS knows. This comment also impacts the content of section 1.4.6 (Requesting User Information). This topic has been first addressed under the issue which is still open. It would be wise to allow such an on-line access so that the user can know which attributes are known by an AS and then choose which attributes to insert into an access token.
Maybe we'll need a bit of rewording, although I'm not sure the proposed changes help so much. I just think we should put more emphasis (and state early on) what is shortly described at the end of section 4, i.e. that here RO = end-user
RO = end-user is not the general case. The usefulness of supporting Requesting RO Information is not crystal clear and should be indicated, but there is an interest to support Requesting User Information. While I agree with you that "we'll need a bit of rewording", simply stating that RO = end-user in section 4 will not solve the issue.
I notice that states It also shows that there is no RS involve and diagram uses label: User (not RO) To my understanding End-user is "logged in" to the client instance. Given role definition: If we don't have RS involved, so we also don't have any Protected Resource here, does it really make sense to speak of Resource Owner?
Yes, that's why we talk about the "user" here. Notice that currently, this term is used when we don't know the exact role it will play in the protocol (end user or RO).
If that's the case for why does speak about Resource Owner? Again in 2.2 we also don't seem to have Resource Server or Protected Resource involved.
The rationale is : in the intro of section 4, gnap allows a large variety of cases. GNAP can handle UMA2 types of scenarii (hence 1.4.6 and a few other places) but in gnap core we mostly detail the case where end-user = RO. Hence what we explain about the subject, and it makes sense to limite the diffusion of confidential information about the RO (the most limiting case, hence 2.2 and a few other places) That's actually a quite subtle difference, but i think it makes good sense.
Given above definitions maybe it would make sense to broaden definition of RO to: subject entity that may grant or deny operations on resources or obtaining assertions it has authority upon. Since in the User acting as RO doesn't grant or deny operations on resources (served by RS) but only grants / denies obtaining an assertion.
I agree that the specific language that NAME references should be tightened up. What's a little awkward right now is that GNAP's language treats access to an RS and access to information contained in assertions as protected resources, but it doesn't do so particularly cleanly due to several major text revisions that have changed things a little out of sync with each other. Both data from an RS (using an access token) and assertions/identifiers passed to the client are targeted at the client itself, so in that way they're the same nature, a protected resource after a fashion and both controlled by an RO of some kind. What's different is that the info passed back directly is usually assumed to be :about: the end-user, because that's what the client is calling about in just about all the use cases that are known. Technically all of the information, either from an RS or subject information passed directly, is controlled by the RO. The end-user can get involved through interaction and act as the RO. The case where the RO doesn't equal the end-user is useful in many situations but leads to unexpected weirdness when you're talking about the subject information coming back.
Fair point. We might start by listing what needs to be changed.
I tend to think of the AS as having a separate service endpoint for RO requests because they are the ones that can edit AS policy. A service endpoint that is accessible to End User requests would be "separate" and could be used by anyone including the RO when they want the protection of least-privilege. This distinction may be unhelpful in the general case of explaining GNAP so I don't mean to overstate it.
NAME when you say "service endpoint" are you thinking of something that's interactive and user-facing (so a webpage) or something that's a callable API?
NAME I really don't know enough to answer purely technical questions. I think mostly in terms of privacy engineering and look to this group for security and devops perspective. Therefore, I focus on the AS as the primary, if not the sole, entity that stores and executes RO policy. The AS takes requests and turns them into access tokens. The requests might be via (RAR) API or a web form. Either way, this request interface is likely unsecured. Some requests present credentials while others might add an authentication flow. That begs the issue of how did the AS get the RO's policies to begin with, long before a request comes in? I would define whoever sets the AS policies as the RO (regardless of any particular RS-RO relationship). A so-called "policy manager API" has been under discussion in UMA for about a year because at least one implementer wants to author policies on a mobile app and standardize the way they are uploaded to the AS. Back to Justin's technical question, I'm trying to implement the shortest distance between OAuth 2 and GNAP in a way that I can understand and explain to others. I'm doing this in FastAPI (because I don't know much beyond elementary Python, because it has built-in OpenAPI documentation, and has some OAuth 2 and JWT functionality). I'm deploying (automagically) to DigitalOcean App Platform in order to be clear about my various security and build shortcuts. I've designed the demo as two separate FastAPI server domains for the RS and AS. A "global" CouchDB instance is deployed for RO policy storage and any state that needs to be saved as part of the protocol demos. -- URL (the AS) and running at https://ognap-URL -- URL and running at https://ognap-rs-URL -- URL The protected resource is going to be_ just a self-verifying vaccine credential (I invented) -- URL -- Some of this is running at URL I've been stuck trying to answer Justin's exact question for quite a while. I think I need to set up the AS (OGNAP) to deliver a PWA to the RO so they can edit policies locally in PouchDB and sync the polices with the CouchDB the AS can access when a request comes in. That forces me to learn URL or something like it. Aside from my long-term goal to upgrade the HIE of One Trustee demo from UMA to GNAP, I'm also hoping to show the W3C and DIF protocol groups how easy it could be to mitigate significant OAuth 2 human rights concerns using GNAP. Any suggestions, help, moral support would be really welcome.
back to NAME and NAME : looking again on this. I guess we could define what we mean by operations. Getting an assertion is an operation, in my view. Or give it as an example. What do you think ?
I think it comes down to whether or not we consider the "subject information", which includes both identifiers and assertions, to be "resources" or not. I always thought they are, but they are definitely a different style of resource than what comes from the RS so maybe we need better wording around it. We talked about it a bit in the long terminology discussion a year ago, but I don't think we ever really landed on a term that fully captures "stuff sent directly to the client by the AS and not accessed through the RS". Identifiers and assertions are the two categories where there's clear demand, but other things could happen through extensions as well.
Does this issue also have to align with authentication flows that build on GNAP? a subject presents a DID or other identifier to a relying party (RP) the RP dereferences the identifier to an AS they trust a request for assertion is made to the AS the AS issues a liveness challenge to the subject the AS returns an assertion and attributes to the RP (the attributes might be accessed indirectly via an access token returned with the assertion) How is SIOP planning to handle this?
In the current draft, section 2.2 : "The AS can determine the RO's identity and permission for releasing this information through interaction with the RO (Section 4), AS policies, or assertions presented by the client instance (Section 2.4). If this is determined positively, the AS MAY return the RO's information in its response (Section 3.4) as requested." Currently, a resource is just a short cut for "Protected resource", which really refers to an API served by a RS. So we have a mismatch (or at least a missing case) in the RO definition (as pointed out by NAME and NAME I've tried some sentences to specify subtypes for resources, but it becomes very confusing. The proposal by NAME to define the RO as "subject entity that may grant or deny operations on resources or obtaining assertions it has authority upon." seems slightly incorrect to me, because the assertion is not made by the RO, but by the AS. What the RO grants to the AS is access to its attributes (and then the AS may carry out further due diligence to derive assertions, for instance through AuthN flows as suggested by NAME The decision to disclose or not its own attributes is not restricted to the RO, it's actually something under the control of every subject. So here's what I'd suggest to solve the issue (new part in bold): update the definition of "Subject: person, organization or device. It decides whether and under which conditions its attributes can be disclosed to other parties." question 1 : should we limit this to physical persons? (from a legal perspective, that makes sense, but then wouldn't an org want to restrict what it shares, cf issues around data sovereignty?). I think the principle could be generic. question 2 : I've added under which conditions because we already discuss that in the text (manual consent, automatic policy, etc.), plus it's not only a yes/no, it also concerns what those other parties can do with it, including further sharing those attributes, cf the case mentioned by NAME where the AS sends them to the RP. Feedback welcome !
section refers to the Subject exclusively as RO. I'm still uncertain if the subject who in interaction only decides to disclose some attributes in an but not any "Protected resources" (an API served by RS) is considered to act as RO. If that's the case what would be the case where the subject decides to disclose some attributes but doesn't act as RO?
I'm not entirely sure about the use case you're targeting here. Could you be more specific ?
Maybe I shouldn't have mixed two questions together. Let's focus on one of them first. section always refers to the Subject as RO. In your previous comment you mentioned that: When we would have a situation where a Subject is deciding to disclose its own attributes but they don't act as RO?
In theory section 4 allows other situations (at the beginning of the section). But the only case that's detailed is the case where it is indeed the RO.
Thanks, now for the second part of my question. In we find: In this scenario, while no RS is participating, so no Protected Resources are being accessed. We still have Shouldn't definition of RO should still be broadened from current Keeping in mind It might still be something in direction of subject entity that may grant or deny operations on resources or obtaining assertions containing attributes it has authority upon. In short, if RO plays role in . There seems to be more to that role than just granting or denying operations on resources (an API served by RS).
My view is that the attribute part is covered by the fact that the RO is a subject (obtaining them is covered by the subject definition now). The main rationale for the protocol is still related to access to protected resources, and I believe we would dilute that otherwise.
In that case is there any reason for to still include: I think 4 could be removed altogether and 5 could become (after renumbering) This section states in the first sentence that it does not involve RS and access to protected resources (an API served by RS)
We still need to make sure that the user is indeed the RO, hence step 4.
I still consider that the information about the subject is counted among the "Resources" being released here. The only real difference is that instead of them being at an RS, they're passed directly to the client instance.
Yes, this didn't change. I'm only saying I don't think it needs to be embedded into the RO definition, since we can assume from the subject definition itself that some mechanism exists to grab the subject attributes data if it consents to. Changing the RO definition or worse the (protected) resource definition makes the entire thing convoluted, at least in every variation I tried.
NAME Right, and I think I agree with that. The definitions should try to stay tight, if we can. But if the surrounding text, especially the "subject information" request stuff isn't clear, then this is going to come around again. I don't have a specific answer but I would be surprised if we can't improve this, since it's come up a few times.
I am supportive of elf-pavlik when he writes: fimbault agrees with him when he says: When looking at Section 3.4 that is indicated in that section, the following text may be found. If information about the RO is requested and the AS grants the client instance access to that data, the AS returns the approved information in the "subject" response field. The case where information is about the end-user is not addressed, i.e. there is no sentence starting with: If information about the end-user is requested (...) Does this mean that an end-user is not allowed to know which personal data is known by the AS about him ? If this would be the case, such a limitation would not comply with generally agreed privacy principles. The text is still not fixed in draft-08. What are the benefits for a client to know information about the RO ? This may be crystal clear for the editor(s), but it is unclear for a lambda reader.
Based on recent conversations, especially URL it seems to me that the intention is to consider the subject as RO with regards to the information about them. I think this shows up clearly in since it does not involve any Protected Resources but it stills call the user RO. It might be helpful to document scenarios where there is more than one AS involved. Let's say we have Alice using a client to access resources owned by Bob. Here we could have two different AS: AS providing user information about Alice to the client - here Alice would act as both End-user and RO and Bob not be involved at all AS providing access_token to the client allowing access for protected resources - here Alice would act as End-user and Bob as RO Does that scenario with two different Authorization Servers sound reasonable?
NAME Those two both make sense, and it makes sense even for them to be together. You could have those be the same AS as well, if Bob's resource server is protected by the same server Alice is using to log in to the client. But they're different kinds of access, and it would make sense to talk about them in a single example scenario to help call out that difference. There's also a weird case from the CIBA work in the OIDF: Alice uses client software to find out who Bob is. The canonical example given here is a call center: Alice needs to verify that the person calling her is actually Bob, and so Alice starts something with the AS that reaches out to Bob to approve the release of identity information about Bob to Alice, in real time.
NAME how does Alice know which AS can release identity information about Bob? I would not make an assumption that one global central AS exists and it has information about the whole Earth's population?
NAME This use case is not assuming a global AS at all (I agree, that's absurd), but it is assuming that Alice and Bob are both working with a known ecosystem. In the case of the call center example, it's the supporting company's AS -- where Alice works and where Bob is a customer. So, Bob needs to have an account there, and so does Alice. Alice's account needs to be authorized to get info about other users (because she's a support tech). Bob's account is a customer account that Alice can fetch information from anyway.
I see, thank you. It indeed looks like another use case where Bob acts as RO but there is no RS or Protected Resource involved.
I've encountered the CIBA use case very recently. Here's a summarised description : the enduser gets in touch (out of band) with the support, so that both are available at the same time the support needs to get read access to some info stored on the enduser's mobile, and uses CIBA to get the enduser's approval returned scopes define what can be accessed through another OIDC client (used by the support agent) there are no RS involved Note : this issue is closed, so either we should reopen it or open a new issue
NAME Agreed, we've drifted off of the topic of the issue as well. I opened up a new issue for discussion of the cross-user CIBA use case specifically:

ability given to a subject to perform a given operation on a resource under the control of an RS. <del> person, organization or device. </del> <ins> person, organization or device.  It decides whether and under which conditions its attributes can be disclosed to other parties. </ins> statement asserted by an AS about a subject.


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as far as the overall protocol is concerned. A single role need not be deployed as a monolithic service.  For <del> example, A client instance could have components that are installed </del> <ins> example, a client instance could have components that are installed </ins> on the end user's device as well as a back-end system that it communicates with.  If both of these components participate in the delegation protocol, they are both considered part of the client


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In some circumstances, the information needed at a given stage is communicated out of band or is preconfigured between the components <del> or entities performing the roles.  For example, one entity can fulfil multiple roles, and so explicit communication between the roles is not necessary within the protocol flow.  Additionally some components may not be involved in all use cases.  For example, a client instance could be calling the AS just to get direct user information and have no need to get an access token to call an RS. </del> <ins> or entities performing the roles.  For example, one entity can fulfill multiple roles, and so explicit communication between the roles is not necessary within the protocol flow.  Additionally some components may not be involved in all use cases.  For example, a client instance could be calling the AS just to get direct user information and have no need to get an access token to call an RS. </ins> 1.5.1.


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The client instance stores the continuation information from (2) for use in (8) and (10).  The client instance then interaction- <del> redirect given by the AS in (2). </del> <ins> usercode given by the AS in (2). </ins> <del> The user's directs their browser to the user code URI.  This URI is stable and can be communicated via the client software's </del> <ins> The users directs their browser to the user code URI.  This URI is stable and can be communicated via the client software's </ins> documentation, the AS documentation, or the client software itself.  Since it is assumed that the RO will interact with the AS through a secondary device, the client instance does not provide a


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The client instance request.  The client instance does not send any interaction modes to the server. <del> The AS determines that the request is been authorized, the AS grants access to the information in the form of response-token to the client instance.  Note that response-subject is not generally </del> <ins> The AS determines that the request has been authorized, the AS grants access to the resource in the form of response-token to the client instance.  Note that response-subject is not generally </ins> applicable in this use case, as there is no user involved. The client instance use-access-token to call the RS.


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the RS again. The RS validates the access token and determines that the access <del> token is expired The RS responds to the client instance with an </del> <ins> token is expired.  The RS responds to the client instance with an </ins> error. The client instance calls the token management URI returned in (2)


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2. <del> To start a request, the client instance sends RFC8259 document with </del> <ins> To start a request, the client instance sends a RFC8259 document with </ins> an object as its root.  Each member of the request object represents a different aspect of the client instance's request.  Each field is described in detail in a section below. Additional members of this request object can be defined by <del> extensions to this protocol as described in </del> <ins> extensions to this protocol as described in request-extending. </ins> A non-normative example of a grant request is below:


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to determine appropriate key information, the client instance can send this instance identifier as a direct reference value in lieu of the "client" object.  The instance identifier MAY be assigned to a <del> client instance at runtime through the response-dynamic-handles or MAY be obtained in another fashion, such as a static registration process at the AS. </del> <ins> client instance at runtime through a grant response (response- dynamic-handles) or MAY be obtained in another fashion, such as a static registration process at the AS. </ins> When the AS receives a request with an instance identifier, the AS MUST ensure that the key used to binding-keys is associated with the


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In response to a client instance's request, the AS responds with a JSON object as the HTTP entity body.  Each possible field is detailed <del> in the sections below </del> <ins> in the sections below. </ins> In this example, the AS is returning an response-interact-redirect, a response-interact-finish, and a response-continue.


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it can request-interact-usercode. The AS determines that interaction is needed and response with a <del> response-interact-usercode.  This could optionally include a URI to direct the user to, but this URI should be static and so could be configured in the client instance's documentation.  The AS also includes information the client instance will need to response- continue in (8) and (10).  The AS associates this continuation information with an ongoing request that will be referenced in (4), (6), (8), and (10). </del> <ins> response-interact-usercode.  The AS also includes information the client instance will need to response-continue in (8) and (10). The AS associates this continuation information with an ongoing request that will be referenced in (4), (6), (8), and (10). </ins> The client instance stores the continuation information from (2) for use in (8) and (10).  The client instance then interaction-


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any interaction modes to the server, indicating that it does not expect to interact with the RO.  The client instance can also signal which RO it requires authorization from, if known, by using <del> the request-user. </del> <ins> the request-user.  It's also possible for the AS to determine which RO needs to be contacted by the nature of what access is being requested. </ins> The AS determines that interaction is needed, but the client instance cannot interact with the RO.  The AS response with the


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After discussion with NAME , this PR now makes keys single-format-only as previously suggested.
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Yaron: why are we sending a JWK as well as a cert? Are we checking that the cert contains the same public key as the cert? Justin: I would be OK with the different formats being mutually exclusive somehow. The AS would need to check that they’re the same and throw an error if not. But this would also let the RC send over whatever it’s got for its own keys every time.
The document has been changed to address this issue, copying my text that refers to the latest draft version: In Sec. 7.1 we allow the client to include multiple keys of different formats, provided they are "equivalent". This doesn't make sense, because the only reason to send multiple keys is that the sender suspects that the recipient doesn't understand one of the formats. But if that's the case, the recipient is not able to validate the MUST requirement that the two formats be equivalent. This could also lead to interesting key injection attacks. IMO we should only allow one key value/format for each request.

response-token-single, the proof of that key MUST be used when presenting the access token. <del> A key presented by value MUST be a public key in at least one supported format.  If a key is sent in multiple formats, all the key format values MUST be equivalent.  Note that while most formats present the full value of the public key, some formats present a value cryptographically derived from the public key.  See additional discussion of public keys in security-symmetric. A key presented by value MUST be a public key in at least one supported format.  If a key is sent in multiple formats, all the key format values MUST be equivalent.  Note that while most formats present the full value of the public key, some formats present a value cryptographically derived from the public key. </del> <ins> A key presented by value MUST be a public key and MUST be presented in one and only one supported format, as discussed in security- multiple-key-formats.  Note that while most formats present the full value of the public key, some formats present a value cryptographically derived from the public key.  See additional discussion of the presentation of public keys in security-symmetric. </ins> Additional key formats are defined in the IANA-key-formats. <del> This non-normative example shows a single key presented in multiple formats.  This example key is intended to be used with the httpsig- binding proofing mechanism, as indicated by the "httpsig" value of the "proof" field. </del> <ins> This non-normative example shows a single key presented in two different formats.  This example key is intended to be used with the httpsig-binding proofing mechanism, as indicated by the "httpsig" value of the "proof" field. As a JSON Web Key: As a certificate in PEM format: </ins> 7.1.1.


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After discussion with NAME , this PR now makes keys single-format-only as previously suggested.
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Yaron: why are we sending a JWK as well as a cert? Are we checking that the cert contains the same public key as the cert? Justin: I would be OK with the different formats being mutually exclusive somehow. The AS would need to check that they’re the same and throw an error if not. But this would also let the RC send over whatever it’s got for its own keys every time.
The document has been changed to address this issue, copying my text that refers to the latest draft version: In Sec. 7.1 we allow the client to include multiple keys of different formats, provided they are "equivalent". This doesn't make sense, because the only reason to send multiple keys is that the sender suspects that the recipient doesn't understand one of the formats. But if that's the case, the recipient is not able to validate the MUST requirement that the two formats be equivalent. This could also lead to interesting key injection attacks. IMO we should only allow one key value/format for each request.

SSRF is somewhat more difficult to manage at runtime, and systems should generally refuse to fetch a URI if unsure. <ins> 12.33. Keys presented by value are allowed to be in only a single format, as discussed in key-format.  Presenting the same key in multiple formats is not allowed and is considered an error in the request.  If multiple keys formats were allowed, receivers of these key definitions need to be able to make sure that it's the same key represented in each field and not simply use one of the key formats without checking for equivalence.  If equivalence were not carefully checked, it is possible for an attacker to insert their own key into one of the formats without needing to have control over the other formats.  This could potentially lead to a situation where one key is used by part of the system (such as identifying the client instance) and a different key in a different format in the same message is used for other things, like calculating signature validity. To combat this, all keys presented by value have to be in exactly one supported format known by the receiver.  Normally, a client instance is going to be configured with its keys in a single format, and it will simply present that format as-is to the AS in its request.  A client instance capable of multiple formats can use discovery to determine which formats are supported, if desired.  An AS should be generous in supporting many different key formats to allow different types of client software and client instance deployments. </ins> 13. The privacy considerations in this section are modeled after the list


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Adds the field for requesting information for a specific user, separate from identifying the current end-user. Also adds a security considerations section addressing asynchronous authorization methods.
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Normally we think about releasing subject information being about the current end-user, but that's not necessarily universal. The use case from CIBA: Alice is a support engineer with a company Bob is a customer of that company Bob calls the company and talks to Alice Alice needs to authenticate, from her system, that Bob is the person tied to the account in question Alice's client messages the AS to request Bob's information (probably including an identifier for Bob in the request) The AS reaches out to Bob to approve Alice's client to get Bob's information Bob approves Alice's request (probably on a pre-enrolled device) The AS sends Bob's information back to Alice's client Note a few key assumptions with this: At no point does Alice's client think that Bob is logging in. Alice and Bob both need accounts of some type at the AS Alice's account (or client) need the rights to request someone else's info Bob's approval mechanism needs to be tied to his account ahead of time (since Bob isn't running the client and the AS needs to reach out to him out of band) Bob's approval needs to be clearly directed to tell Bob that it's Alice (and alice's client) asking for his info Alice might need to log in / interact with the AS as part of this, or it might be tied to the client instance (maybe Alice has logged in for the day and that association is remembered by the AS?)
This is an interesting use case. Yet CIBA doesn't necessarily require an AS to work, as long as one is only interested in getting scopes. Is there a generic use case for cross-user subject information + required AS? Or maybe we should explain the added value of the AS in that specific case ?
We will add an example in section D that shows how this would work and verify that the language around subject identifiers is sufficiently robust to encapsulate this. This might also add additional security and privacy considerations when used in this mode because multiple people are now involved explicitly.
I think this could be marked as NEEDS TEXT ?
I think it mostly just needs to be added as an example, and I can do that.
Fine ;-) (on my side, I always tend to consider CIBA as some degenerate phishing experiment, but maybe that's too extreme)

An example set of protocol messages for this method can be found in example-async. <ins> Additional considerations for asynchronous interactions like this are discussed in security-async. </ins> 1.6.5. In this example flow, the AS policy allows the client instance to


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Adds the field for requesting information for a specific user, separate from identifying the current end-user. Also adds a security considerations section addressing asynchronous authorization methods.
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Normally we think about releasing subject information being about the current end-user, but that's not necessarily universal. The use case from CIBA: Alice is a support engineer with a company Bob is a customer of that company Bob calls the company and talks to Alice Alice needs to authenticate, from her system, that Bob is the person tied to the account in question Alice's client messages the AS to request Bob's information (probably including an identifier for Bob in the request) The AS reaches out to Bob to approve Alice's client to get Bob's information Bob approves Alice's request (probably on a pre-enrolled device) The AS sends Bob's information back to Alice's client Note a few key assumptions with this: At no point does Alice's client think that Bob is logging in. Alice and Bob both need accounts of some type at the AS Alice's account (or client) need the rights to request someone else's info Bob's approval mechanism needs to be tied to his account ahead of time (since Bob isn't running the client and the AS needs to reach out to him out of band) Bob's approval needs to be clearly directed to tell Bob that it's Alice (and alice's client) asking for his info Alice might need to log in / interact with the AS as part of this, or it might be tied to the client instance (maybe Alice has logged in for the day and that association is remembered by the AS?)
This is an interesting use case. Yet CIBA doesn't necessarily require an AS to work, as long as one is only interested in getting scopes. Is there a generic use case for cross-user subject information + required AS? Or maybe we should explain the added value of the AS in that specific case ?
We will add an example in section D that shows how this would work and verify that the language around subject identifiers is sufficiently robust to encapsulate this. This might also add additional security and privacy considerations when used in this mode because multiple people are now involved explicitly.
I think this could be marked as NEEDS TEXT ?
I think it mostly just needs to be added as an example, and I can do that.
Fine ;-) (on my side, I always tend to consider CIBA as some degenerate phishing experiment, but maybe that's too extreme)

returned and it might not match what the client instance requested, see the section on subject information for details. <ins> 1.6.8. In this scenario, the end user and resource owner are two different people.  In this scenario, the client instance already knows who the end user is, likely through a separate authentication process.  The end user, operating the client instance, needs to get subject information about another person in the system, the RO.  The RO is given an opportunity to release this information using an asynchronous interaction method with the AS.  This scenario would apply, for instance, when the end user is an agent in a call-center and the resource owner is a customer authorizing the call center agent to access their account on their behalf. Precondition: The end user is authenticated to the client instance, and the client instance has an identifier representing the end user that it can present to the AS.  This identifier should be unique to the particular session with the client instance and the AS. The RO communicates a human-readable identifier to the end user, such as an email address or account number.  This communication happens out of band from the protocol, such as over the phone between parties.  Note that the RO is not interacting with the client instance. The end user communicates the identifier to the client instance. The means by which the identifier is communicated to the client instance is out of scope for this specification. The client instance request.  The request includes the RO's identifier in the request-subject "sub_ids" field, and the end user's identifier in the request-user of the request.  The request includes no interaction start methods, since the end user is not expected to be the one interacting with the AS.  The request does include the request-interact-callback-push to allow the AS to signal to the client instance when the interaction with the RO has concluded. The AS sees that the identifier for the end user and subject being requested are different.  The AS determines that it can reach out to the RO asynchronously for approval.  While it is doing so, the AS returns a response-continue with a "finish" nonce to allow the client instance to keep polling after interaction with the RO has concluded. The AS contacts the RO and has them authenticate to the system. The means for doing this are outside the scope of this specification, but the identity of the RO is known from the subject identifier sent in (3). The RO is prompted to authorize the end user's request via the client instance.  Since the end user was identified in (3) via the user field, the AS can show this information to the RO during the authorization request. The RO completes the authorization with the AS.  The AS marks the request as . The RO pushes the interaction-pushback to the client instance. Note that in the case the RO cannot be reached or the RO denies the request, the AS still sends the interaction finish message to the client instance, after which the client instance can negotiate next steps if possible. The client instance validates the interaction finish message and continue-after-interaction. The AS returns the RO's response-subject to the client instance. The client instance can display or otherwise utilize the RO's user information in its session with the end user.  Note that since the client instance requested different sets of user information in (3), the client instance does not conflate the end user with the RO. Additional considerations for asynchronous interactions like this are discussed in security-async. </ins> 2. To start a request, the client instance sends a RFC8259 document with


Question:
Adds the field for requesting information for a specific user, separate from identifying the current end-user. Also adds a security considerations section addressing asynchronous authorization methods.
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Normally we think about releasing subject information being about the current end-user, but that's not necessarily universal. The use case from CIBA: Alice is a support engineer with a company Bob is a customer of that company Bob calls the company and talks to Alice Alice needs to authenticate, from her system, that Bob is the person tied to the account in question Alice's client messages the AS to request Bob's information (probably including an identifier for Bob in the request) The AS reaches out to Bob to approve Alice's client to get Bob's information Bob approves Alice's request (probably on a pre-enrolled device) The AS sends Bob's information back to Alice's client Note a few key assumptions with this: At no point does Alice's client think that Bob is logging in. Alice and Bob both need accounts of some type at the AS Alice's account (or client) need the rights to request someone else's info Bob's approval mechanism needs to be tied to his account ahead of time (since Bob isn't running the client and the AS needs to reach out to him out of band) Bob's approval needs to be clearly directed to tell Bob that it's Alice (and alice's client) asking for his info Alice might need to log in / interact with the AS as part of this, or it might be tied to the client instance (maybe Alice has logged in for the day and that association is remembered by the AS?)
This is an interesting use case. Yet CIBA doesn't necessarily require an AS to work, as long as one is only interested in getting scopes. Is there a generic use case for cross-user subject information + required AS? Or maybe we should explain the added value of the AS in that specific case ?
We will add an example in section D that shows how this would work and verify that the language around subject identifiers is sufficiently robust to encapsulate this. This might also add additional security and privacy considerations when used in this mode because multiple people are now involved explicitly.
I think this could be marked as NEEDS TEXT ?
I think it mostly just needs to be added as an example, and I can do that.
Fine ;-) (on my side, I always tend to consider CIBA as some degenerate phishing experiment, but maybe that's too extreme)

12.34. <ins> GNAP allows the RO to be contacted by the AS asynchronously, outside the regular flow of the protocol.  This allows for some advanced use cases, such as cross-user authentication or information release, but such advanced use cases have some distinct issues that implementors need to be fully aware of before using these features. First, in many applications, the return of a subject information to the client instance could indicate to the client instance that the end-user is the party represented by that information, functionally allowing the end-user to authenticate to the client application. While the details of a fully functional authentication protocol are outside the scope of GNAP, it is a common exercise for a client instance to be requesting information about the end user.  This is facilitated by the several interaction-start defined in GNAP that allow the end user to begin interaction directly with the AS. However, when the subject of the information is intentionally not the end-user, the client application will need some way to differentiate between requests for authentication of the end user and requests for information about a different user.  Confusing these states could lead to an attacker having their account associated with a privileged user.  Client instances can mitigate this by having distinct code paths for primary end user authentication and requesting subject information about secondary users, such as in a call center.  In such use cases, the client software used by the resource owner (the caller) and the end-user (the agent) are generally distinct, allowing the AS to differentiate between the agent's corporate device making the request and the caller's personal device approving the request. Second, RO's interacting asynchronously do not usually have the same context as an end user in an application attempting to perform the task needing authorization.  As such, the asynchronous requests for authorization coming to the RO from the AS might have very little to do with what the RO is doing at the time.  This situation can consequently lead to authorization fatigue on the part of the RO, where any incoming authorization request is quickly approved and dispatched without the RO making a proper verification of the request.  An attacker can exploit this fatigue and get the RO to authorize the attacker's system for access.  To mitigate this, AS systems deploying asynchronous authorization should only prompt the RO when the RO is expecting such a request, and significant user experience engineering efforts need to be employed to ensure the RO can clearly make the appropriate security decision.  Furthermore, audit capability, and the ability to undo access decisions that may be ongoing, is particularly important in the asynchronous case. </ins> An attacker may aim to gain access to confidential or sensitive resources.  The measures for hardening and monitoring resource server systems (beyond protection with access tokens) is out of the scope of


Question:
Just two minor typos I stumbled across.
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4.2. If an interaction response-interact-finish method is associated with <del> the current request, the AS MUST follow the appropriate method at upon completion of interaction in order to signal the client instance to continue, except for some limited error cases discussed below.  If a finish method is not available, the AS SHOULD instruct the RO to </del> <ins> the current request, the AS MUST follow the appropriate method upon completion of interaction in order to signal the client instance to continue, except for some limited error cases discussed below.  If a finish method is not available, the AS SHOULD instruct the RO to </ins> return to the client instance upon completion. The AS MUST create an interaction reference and associate that


Question:
Just two minor typos I stumbled across.
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appropriate cryptographic processes to ensure the integrity of the assertion. <del> For example, when SAML 2 assertions are used, the receiver hast to </del> <ins> For example, when SAML 2 assertions are used, the receiver has to </ins> parse an XML document.  There are many well-known security vulnerabilities in XML parsers, and the XML standard itself can be attacked through the use of processing instructions and entity


Question:
clarify that user codes are unguessable, - update user code examples,
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This is very minor, but there's a contradiction between the usercode provided in the example in section 3.3.3. and the recommendations that are mentioned in the text above it. The text says: And However, the example provided below it goes against these two recommendations, as it contains a special character (a hyphen) rather than just letters and numbers, and it's longer than eight characters in length: I'd suggest either tweaking the wording, or tweaking the example so that the usercode provided in the example is aligned to the recommendations mentioned in the text.
The specification does not require user codes to be unguessable. Section 3.3.3 (Display of a Short User Code) states that user codes have to be unique and should be short-lived, but this does not imply that codes should be unguessable. It seems that Section 13.27 (Exhaustion of Random Value Space) does not apply to user codes, but to values that are clearly random values "such as nonces, tokens, and randomized URIs". If attackers can guess user codes, the same attack described in URL is possible.
Good catch! The intent is for these to be unguessable, so we can add that explicitly.

usercode and the AS supports this mode for the client instance's request, the AS responds with a "user_code" field.  This field is string containing a unique short code that the user can type into a <del> web page.  This string MUST be case-insensitive, MUST consist of only easily typeable characters (such as letters or numbers).  The time in which this code will be accepted SHOULD be short lived, such as several minutes.  It is RECOMMENDED that this code be no more than </del> <ins> web page.  To facilitate usability, this string MUST be case- insensitive, MUST consist of only easily typeable characters (such as letters or numbers).  The string MUST be randomly generated so as to be unguessable by an attacker within the time it is accepted.  The time in which this code will be accepted SHOULD be short lived, such as several minutes.  It is RECOMMENDED that this code be no more than </ins> eight characters in length. The client instance MUST communicate the "user_code" value to the end


Question:
clarify that user codes are unguessable, - update user code examples,
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This is very minor, but there's a contradiction between the usercode provided in the example in section 3.3.3. and the recommendations that are mentioned in the text above it. The text says: And However, the example provided below it goes against these two recommendations, as it contains a special character (a hyphen) rather than just letters and numbers, and it's longer than eight characters in length: I'd suggest either tweaking the wording, or tweaking the example so that the usercode provided in the example is aligned to the recommendations mentioned in the text.
The specification does not require user codes to be unguessable. Section 3.3.3 (Display of a Short User Code) states that user codes have to be unique and should be short-lived, but this does not imply that codes should be unguessable. It seems that Section 13.27 (Exhaustion of Random Value Space) does not apply to user codes, but to values that are clearly random values "such as nonces, tokens, and randomized URIs". If attackers can guess user codes, the same attack described in URL is possible.
Good catch! The intent is for these to be unguessable, so we can add that explicitly.

When the end user is directed to enter a short code through the response-interact-usercode mode, the client instance communicates the user code to the end user and directs the end user to enter that code <del> at an associated URI.  This mode is designed to be used when the client instance is not able to communicate or facilitate launching an arbitrary URI.  The associated URI could be statically configured with the client instance or in the client software's documentation. As a consequence, these URIs SHOULD be short.  The user code URI MUST be reachable from the end user's browser, though the URI is usually be opened on a separate device from the client instance itself.  The URI MUST be accessible from an HTTP GET request and MUST be protected by HTTPS or equivalent means. </del> <ins> at an associated URI.  The client instance MAY format the user code in such a way as to facilitate memorability and transfer of the code, so long as this formatting does not alter the value as accepted at the user code URI.  For example, a client instance receiving the user code "A1BC3DFF" could choose to display this to the user as "A1BC 3DFF", breaking up the long string into two shorter strings.  In this example, the space in between the two parts would be removed upon its entry into the user code URI. This mode is designed to be used when the client instance is not able to communicate or facilitate launching an arbitrary URI.  The associated URI could be statically configured with the client instance or in the client software's documentation.  As a consequence, these URIs SHOULD be short.  The user code URI MUST be reachable from the end user's browser, though the URI is usually be opened on a separate device from the client instance itself.  The URI MUST be accessible from an HTTP GET request and MUST be protected by HTTPS or equivalent means. </ins> In many cases, the URI indicates a web page hosted at the AS, allowing the AS to authenticate the end user as the RO and


Question:
clarify that user codes are unguessable, - update user code examples,
To edit notification comments on pull requests, go to your .
This is very minor, but there's a contradiction between the usercode provided in the example in section 3.3.3. and the recommendations that are mentioned in the text above it. The text says: And However, the example provided below it goes against these two recommendations, as it contains a special character (a hyphen) rather than just letters and numbers, and it's longer than eight characters in length: I'd suggest either tweaking the wording, or tweaking the example so that the usercode provided in the example is aligned to the recommendations mentioned in the text.
The specification does not require user codes to be unguessable. Section 3.3.3 (Display of a Short User Code) states that user codes have to be unique and should be short-lived, but this does not imply that codes should be unguessable. It seems that Section 13.27 (Exhaustion of Random Value Space) does not apply to user codes, but to values that are clearly random values "such as nonces, tokens, and randomized URIs". If attackers can guess user codes, the same attack described in URL is possible.
Good catch! The intent is for these to be unguessable, so we can add that explicitly.

When the end user is directed to enter a short code through the response-interact-usercodeuri mode, the client instance communicates the user code and associated URI to the end user and directs the end <del> user to enter that code at the URI.  This mode is used when the client instance is not able to facilitate launching a complex arbitrary URI but can communicate arbitrary values like URIs.  As a consequence, these URIs SHOULD be short to allow the URI to be typed by the end user.  The client instance MUST NOT modify the URI when communicating it to the end user; in particular the client instance MUST NOT add any parameters to the URI.  The user code URI MUST be reachable from the end user's browser, though the URI is usually be opened on a separate device from the client instance itself.  The URI MUST be accessible from an HTTP GET request and MUST be protected by HTTPS or equivalent means. </del> <ins> user to enter that code at the URI.  The client instance MAY format the user code in such a way as to facilitate memorability and transfer of the code, so long as this formatting does not alter the value as accepted at the user code URI.  For example, a client instance receiving the user code "A1BC3DFF" could choose to display this to the user as "A1BC 3DFF", breaking up the long string into two shorter strings.  In this example, the space in between the two parts would be removed upon its entry into the user code URI. This mode is used when the client instance is not able to facilitate launching a complex arbitrary URI but can communicate arbitrary values like URIs.  As a consequence, these URIs SHOULD be short to allow the URI to be typed by the end user.  The client instance MUST NOT modify the URI when communicating it to the end user; in particular the client instance MUST NOT add any parameters to the URI.  The user code URI MUST be reachable from the end user's browser, though the URI is usually be opened on a separate device from the client instance itself.  The URI MUST be accessible from an HTTP GET request and MUST be protected by HTTPS or equivalent means. </ins> In many cases, the URI indicates a web page hosted at the AS, allowing the AS to authenticate the end user as the RO and


Question:
clarify that user codes are unguessable, - update user code examples,
To edit notification comments on pull requests, go to your .
This is very minor, but there's a contradiction between the usercode provided in the example in section 3.3.3. and the recommendations that are mentioned in the text above it. The text says: And However, the example provided below it goes against these two recommendations, as it contains a special character (a hyphen) rather than just letters and numbers, and it's longer than eight characters in length: I'd suggest either tweaking the wording, or tweaking the example so that the usercode provided in the example is aligned to the recommendations mentioned in the text.
The specification does not require user codes to be unguessable. Section 3.3.3 (Display of a Short User Code) states that user codes have to be unique and should be short-lived, but this does not imply that codes should be unguessable. It seems that Section 13.27 (Exhaustion of Random Value Space) does not apply to user codes, but to values that are clearly random values "such as nonces, tokens, and randomized URIs". If attackers can guess user codes, the same attack described in URL is possible.
Good catch! The intent is for these to be unguessable, so we can add that explicitly.

13.27. Several parts of the GNAP process make use of unguessable randomized <del> values, such as nonces, tokens, and randomized URIs.  Since these values are intended to be unique, a sufficiently powerful attacker could make a large number of requests to trigger generation of randomized values in an attempt to exhaust the random number </del> <ins> values, such as nonces, tokens, user codes, and randomized URIs. Since these values are intended to be unique, a sufficiently powerful attacker could make a large number of requests to trigger generation of randomized values in an attempt to exhaust the random number </ins> generation space.  While this attack is particularly applicable to the AS, client software could likewise be targeted by an attacker triggering new grant requests against an AS.


Question:
NAME Please take a look at this updated text to see if it addresses your concerns.
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Thinking about possible extensions to GNAP's interaction modes, I had the impression that the specification could be a bit clearer regarding requirements on such extensions. From reading Section 3.3, my understanding is that all implementations of GNAP, including ones using extensions which define additional interaction finish methods, MUST include a nonce in the grant response (given that the AS wants to use the finish method offered by the client instance): URL However, Section 3.3.5 sounds a bit different, only referring to the two interaction finish methods defined by GNAP core: URL Section 4.2 could be a bit clearer as to what is expected of future extensions to GNAP, it currently says: URL with the two following sections describing the finish methods defined by GNAP core. This is, however, somewhat clearer in Section 4.2.3: I.e., Section 4.2.3 implies that AS must (somehow) provide the client instance with an interaction reference and interaction finish nonce. But it may be helpful to make this more explicit throughout the relevant Sections. There seem to be no requirements for future interaction start methods. It may be helpful to document some minimal requirements, e.g., enough information to identify the grant has to be conveyed to AS via RO in the interaction start (such as the redirect URI in GNAP core).
Thanks NAME for taking the time! The proposed text looks good to me (just one possible typo, I'm not a native speaker, so I'm not 100% sure about that).

This specification defines the following interaction start modes: <ins> All interaction start method definitions MUST provide enough information to uniquely identify the grant request during the interaction.  In the "redirect" and "app" modes, this is done using a unique URI (including its parameters).  In the "user_code" and "user_code_uri" mode, this is done using the value of the user code. </ins> Additional start modes are defined in the IANA-interaction-start- modes.


Question:
NAME Please take a look at this updated text to see if it addresses your concerns.
To edit notification comments on pull requests, go to your .
Thinking about possible extensions to GNAP's interaction modes, I had the impression that the specification could be a bit clearer regarding requirements on such extensions. From reading Section 3.3, my understanding is that all implementations of GNAP, including ones using extensions which define additional interaction finish methods, MUST include a nonce in the grant response (given that the AS wants to use the finish method offered by the client instance): URL However, Section 3.3.5 sounds a bit different, only referring to the two interaction finish methods defined by GNAP core: URL Section 4.2 could be a bit clearer as to what is expected of future extensions to GNAP, it currently says: URL with the two following sections describing the finish methods defined by GNAP core. This is, however, somewhat clearer in Section 4.2.3: I.e., Section 4.2.3 implies that AS must (somehow) provide the client instance with an interaction reference and interaction finish nonce. But it may be helpful to make this more explicit throughout the relevant Sections. There seem to be no requirements for future interaction start methods. It may be helpful to document some minimal requirements, e.g., enough information to identify the grant has to be conveyed to AS via RO in the interaction start (such as the redirect URI in GNAP core).
Thanks NAME for taking the time! The proposed text looks good to me (just one possible typo, I'm not a native speaker, so I'm not 100% sure about that).

methods: If interaction finishing is supported for this client instance and <del> request, the AS response-interact-finish used by the client instance to validate the callback.  Requests to the callback URI MUST be processed as described in interaction-finish, and the AS MUST require presentation of an interaction callback reference as described in continue-after-interaction. </del> <ins> request, the AS will response-interact-finish used by the client instance to validate the callback.  All interaction finish methods MUST use this nonce to allow the client to verify the connection between the pending interaction request and the callback.  GNAP does this through the use of the interaction hash, defined in interaction- hash.  All requests to the callback URI MUST be processed as described in interaction-finish. All interaction finish methods MUST require presentation of an interaction reference for continuing this grant request.  This means that the the interaction reference MUST be returned by the AS and MUST be presented by the client as described in continue-after- interaction.  The means by which the interaction reference is returned to the client instance is specific to the interaction finish method. </ins> 2.5.2.1.


Question:
NAME Please take a look at this updated text to see if it addresses your concerns.
To edit notification comments on pull requests, go to your .
Thinking about possible extensions to GNAP's interaction modes, I had the impression that the specification could be a bit clearer regarding requirements on such extensions. From reading Section 3.3, my understanding is that all implementations of GNAP, including ones using extensions which define additional interaction finish methods, MUST include a nonce in the grant response (given that the AS wants to use the finish method offered by the client instance): URL However, Section 3.3.5 sounds a bit different, only referring to the two interaction finish methods defined by GNAP core: URL Section 4.2 could be a bit clearer as to what is expected of future extensions to GNAP, it currently says: URL with the two following sections describing the finish methods defined by GNAP core. This is, however, somewhat clearer in Section 4.2.3: I.e., Section 4.2.3 implies that AS must (somehow) provide the client instance with an interaction reference and interaction finish nonce. But it may be helpful to make this more explicit throughout the relevant Sections. There seem to be no requirements for future interaction start methods. It may be helpful to document some minimal requirements, e.g., enough information to identify the grant has to be conveyed to AS via RO in the interaction start (such as the redirect URI in GNAP core).
Thanks NAME for taking the time! The proposed text looks good to me (just one possible typo, I'm not a native speaker, so I'm not 100% sure about that).

hash.  The client instance will use this value to validate the "finish" call. <del> The AS MUST send the hash and interaction reference based on the interaction finish mode as described in the following sections. </del> <ins> All interaction finish methods MUST define a way to convey the hash and interaction reference back to the client instance.  When an interaction finish method is used, the client instance MUST present the interaction reference back to the AS as part of its continue- after-interaction. </ins> Note that in many error cases, such as when the RO has denied access, the "finish" method is still enacted by the AS.  This pattern allows


Question:
Expands the discovery document and aligns it with changes made to the discovery process in core. Addresses
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3.1. A GNAP AS offering RS-facing services can publish its features on a <del> well-known discovery document using the URL ".well-known/gnap-as-rs". </del> <ins> well-known discovery document using the URL ".well-known/gnap-as-rs" appended to the grant request endpoint URL. </ins> <del> This endpoint contains a JSON document RFC8259 consisting of a single JSON object with any combination of the following optional fields: </del> <ins> The discovery response is a JSON document RFC8259 consisting of a single JSON object with the following fields: </ins> <del> The URL of the endpoint offering introspection. </del> <ins> OPTIONAL.  The URL of the endpoint offering introspection.  The location MUST be a URL RFC3986 with a scheme component that MUST be https, a host component, and optionally, port, path and query components and no fragment components. </ins> A list of token formats supported by this AS. <del> The URL of the endpoint offering resource registration. The grant endpoint of the GNAP AS. </del> <ins> The URL of the endpoint offering resource registration.  The location MUST be a URL RFC3986 with a scheme component that MUST be https, a host component, and optionally, port, path and query components and no fragment components. REQUIRED.  The location of the AS's grant request endpoint, used by the RS to derive downstream access tokens.  The location MUST be a URL RFC3986 with a scheme component that MUST be https, a host component, and optionally, port, path and query components and no fragment components.  This URL MUST be the same URL used by client instances in support of GNAP requests. OPTIONAL.  A list of the AS's supported key proofing mechanisms. The values of this list correspond to possible values of the "proof" field of the key section of the request. </ins> 3.2.


Question:
Expands the definition of the resource set registration protocol, used by an RS to declare a resource set to an AS at runtime and receive a reference identifier for that resource set to hand to a client.
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Registering a Resource Handle: 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 RS needs to, it can post a set of resources as described in the Resource Access Rights section of I-D.ietf-gnap-core-protocol to <del> the AS's resource registration endpoint. </del> <ins> the AS's resource registration endpoint along with information about what the RS will need to validate the request. REQUIRED.  The list of access rights associated with the request in the format described in the "Resource Access Rights" section of I-D.ietf-gnap-core-protocol. REQUIRED.  The identification used to authenticate the resource server making this call, either by value or by reference as described in authentication. OPTIONAL.  The token format required to access the identified resource.  If the field is omitted, the token format is at the discretion of the AS.  If the AS does not support the requested token format, the AS MUST return an error to the RS. OPTIONAL.  If present and set to "true", the RS expects to make a token introspection request as described in introspection.  If absent or set to "false", the RS does not anticipate needing to make an introspection request for tokens relating to this resource set. </ins> The RS MUST identify itself with its own key and sign the request. <del> The AS responds with a handle appropriate to represent the resources list that the RS presented. </del> <ins> The AS responds with a reference appropriate to represent the resources list that the RS presented in its request as well as any additional information the RS might need in future requests. REQUIRED.  A single string representing the list of resources registered in the request.  The RS MAY make this handle available to a client instance as part of a discovery response as described in I-D.ietf-gnap-core-protocol or as documentation to client software developers. </ins> <del> The RS MAY make this handle available as part of a discovery response as described in I-D.ietf-gnap-core-protocol or as documentation to developers. </del> <ins> OPTIONAL.  An instance identifier that the RS can use to refer to itself in future calls to the AS, in lieu of sending its key by value. </ins> <del> [[ See issue #117 [2] ]] </del> <ins> OPTIONAL.  The introspection endpoint of this AS, used to allow the RS to perform token introspection. </ins> 4.


Question:
Expands the definition of the resource set registration protocol, used by an RS to declare a resource set to an AS at runtime and receive a reference identifier for that resource set to hand to a client.
:heavycheckmark: Deploy Preview for gnap-resource-servers-editors-draft ready! :hammer: Explore the source changes: f9aac0b2af163c0f9a58ba17e93db7e8956140bf :mag: Inspect the deploy log: :sunglasses: Browse the preview:
Registering a Resource Handle: 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

itself with its own key in the "client" field and sign the request just as any client instance would. <del> [[ See issue #116 [3] ]] </del> <ins> [[ See issue #116 [2] ]] </ins> The AS responds with a token for the downstream RS2 as described in I-D.ietf-gnap-core-protocol.  The downstream RS2 could repeat this


Question:
Expands the definition of the resource set registration protocol, used by an RS to declare a resource set to an AS at runtime and receive a reference identifier for that resource set to hand to a client.
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Registering a Resource Handle: 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

[1] https://github.com/ietf-wg-gnap/gnap-core-protocol/issues/115 <del> [2] https://github.com/ietf-wg-gnap/gnap-core-protocol/issues/117 [3] https://github.com/ietf-wg-gnap/gnap-core-protocol/issues/116 </del> <ins> [2] https://github.com/ietf-wg-gnap/gnap-core-protocol/issues/116 </ins>


Question:
Updates token introspection definitions into a more full protocol offered by the AS.
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Introspecting a Token: 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 the RS's keys instead of the RC's or token's keys.
From a privacy point of view, token introspection allows an AS to know exactly when operation(s) are being performed by an end-user on a RS. This provides useful information for ASs that may be tempted to act as "Big Brother". For that reason, the risks related to token introspection should be advertised in the Privacy Considerations section. Its usage should be deprecated in the general case. If there exists specific cases where there is no such a risk, these cases should be advertised.
The section doesn't provide any information on what happens when a client wants to introspect an inactive/invalid/revoked token.
Yes, this is pretty thin right now. It's the RS that introspects the token, and this section will be pulled out into a separate spec to make that more clear (). The response for both positive and negative situations is likely to be based on the OAuth introspection spec, RFC7662 URL
We should add: the AS MUST validate that the token is appropriate for the RS that presented it, and return an error otherwise.
In OAuth token introspection, the AS doesn't return an error in this stated case -- it simply says the token presented is not active, in order to prevent information leakage to a nosy RS.
NAME I don't understand your argument about a "nosy RS". The text states: As a consequence, if the AS does not recognize the signature, it can return a error stating "bad signature". If the signature is correct, the AS can provide all details to the recognized RS, as yaronf mentioned.
s/error/inactive status/.
Token Introspection: it is not clear to what depth we are defining the API: is it only the existence of the "introspect" endpoint? Or do we define a minimal set of standard attributes that need to be returned? The API would not be useful for interoperability unless we define some of the returned attributes. At the very least: "active".
The idea would be to define a core attribute set with extension points like RFC7662. This same attribute set could be used for the token model (but maybe not format?) described in

The RS signs the request with its own key and sends the access token as the body of the request. <ins> REQUIRED.  The access token value presented to the RS by the client instance. RECOMMENDED.  The proofing method used by the client instance to bind the token to the RS request. REQUIRED.  The identification used to authenticate the resource server making this call, either by value or by reference as described in authentication. OPTIONAL.  The minimum access rights required to fulfill the request.  This MUST be in the format described in the Resource Access Rights section of I-D.ietf-gnap-core-protocol. The AS MUST validate the access token value and determine if the token is active.  An active access token is defined as a token that was issued by the processing AS, has not been revoked, has not expired, and is appropriate for presentation at the identified RS. </ins> 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 <del> material.  The response MAY include any fields defined in an access token response. </del> <ins> material. REQUIRED.  If "true", the access token presented is active, as defined above.  If any of the criteria for an active token are not true, or if the AS is unable to make a determination (such as the token is not found), the value is set to "false" and other fields are omitted. If the access token is active, additional fields from the single access token response structure defined in I-D.ietf-gnap-core- protocol are included.  In particular, these include the following: REQUIRED.  The access rights associated with this access token. This MUST be in the format described in the Resource Access Rights section of I-D.ietf-gnap-core-protocol.  This array MAY be filtered or otherwise limited for consumption by the identified RS, including being an empty array. REQUIRED if the token is bound.  The key bound to the access token, to allow the RS to validate the signature of the request from the client instance.  If the access token is a bearer token, this MUST NOT be included. OPTIONAL.  The set of flags associated with the access token. The response MAY include any additional fields defined in an access token response and MUST NOT include the access token "value" itself. </ins> 3.4.


Question:
more details on encoding application group name, for
Reading the paragraph after "An application group can be named in many ways", I was left a bit confused: Why should it be encoded in the Uri-Query? That'd need coordination among all applications running on that host (for it is interfering with the query argument space that's usually left for the application to use). The common partitioning of applications inside a host is left-to-right in the URI, and that puts it in the very last spot. I think I do see what is meant by the discouragement of using the Uri-Host, but doubt that it'd be immediately obvious to general readers. How I understand Uri-Host to be impractical here is that while the request is sent to a well-defined and named URI, the response is a representation of the same URI with the individual server's IP replaced into the authority component, and if two application groups on the same CoAP group use the same path, then there may be clashes, not on the request-response layer (where the responses are bound to request for a particular host name) but in the client's cache of the responses. (And once one is at the point where application groups in the same CoAP group have a disjunct path set, one can do away with identification altogether and just address the unique path). I don't quite follow how this is not "as intended in RFC7252": It is an identifier for who is being addressed, and as such just part of the URI. (For example, if I define my lights group to be named URL and name the resource , then the host name is exactly the group name, and already needs to be put into the request unless there is known URI aliasing). See also URL on "send a Uri-Host" option, with the caveat that I'm a strong proponent of answer A2. Furthermore, the text seems to imply that virtual hosting is something a server would need to go out of its way to implement. It isn't: The Uri-Host option is critical, and a host needs to make the conscious decision to ignore that option; otherwise it's just as much part of finding the addressed resource as all the other Uri-* options are. The best practice is something I can get behind, although I suggest using no identifier on the wire (and just the disjunct set of resources) as a byte saving alternative when the administrative effort of ensuring path uniqueness can be afforded.
Thanks; we do need to improve the current text on these aspects. On Uri-Host and your example "URL" where authority component includes the application group: in this group communication example the sending client would normally DNS-resolve "URL" to a particular multicast IP address, then send the CoAP request to this multicast IP address destination, without including any Uri-Host Option. This works as long as you have a unique 1:1 association between application-group and CoAP-group. In case multiple application-groups map to a single CoAP-group, this doesn't work anymore : a client could be e.g. configured to always include the "Uri-Host" Option to indicate the hostname. Still not the preferred approach I would think. Btw I can't follow answer A2 on the CoAP-Faq, unfortunately: formulation is too complex. In some (common?) constrained use cases, the DNS name would not even be configured in the client and the client would just be configured directly with the IPv6 multicast address of the CoAP group to send it to. Then, the application-group would need to be encoded in some way still, e.g. using the Uri-Path Option. Now what our original text tried to suggest is to "misuse" a Uri-Host Option for that. So instead of using an option like: Uri-Path = group123 You would instead use an option: Uri-Host = group123 So this is not a "real" URI hostname but rather a low-level hack to let the client's CoAP stack insert by force an additional option just before sending out the CoAP request. The receiver's CoAP stack would just parse it as the ID of the application-group and not really as a URI-host. Because this gets confusing and potentially messy (proven by the present discussion !) we don't recommend it. So, trying to reiterate if one has configured Group URIs of the form coap://[mcast-ip-address]/resource on the client then by default the Uri-Host Option would get elided. The above mentioned "hack" is to put it back to encode application-group. This has the issue that the application-group name isn't present in the Group URI. if one has configured Group URIs of the form URL on the client then normally by default the authority gets resolved to some IP multicast address before sending it out, and thus while sending it the Uri-Host Option is NOT included in the CoAP encoding but elided. So the receiving server doesn't see the application-group ID because it's not encoded in the request data. (We assume here that multiple application-groups use the same CoAP-group.) Maybe we should discuss this further; what's the effort here / who ensures it / unique between what and what?
Initial text proposed in above PR! We'll merge it in by tomorrow evening, as an improvement (hopefully). What is not included yet is a statement saying that we don't recommend using the non-Group-URI methods of encoding application group name. To do so we would need to clearly state why that is not recommended; still not clear at this moment what the disadvantages of these are.

control application were shown in Section 2.2 of RFC7390. An application group can be named in many ways through different <del> types of identifiers, such as numbers, URIs or other strings.  An application group name or identifier, if explicitly encoded in a CoAP request, is typically included in the path component or in the query component of a Group URI.  It may also be encoded using the Uri-Host Option RFC7252 in case application group members implement a virtual CoAP server specific to that application group.  The application group can then be identified by the value of the Uri-Host Option and each virtual server serves one specific application group.  However, encoding the application group in the Uri-Host Option is not the preferred method because in this case the application group cannot be encoded in a Group URI, and also the Uri-Host Option is being used for another purpose than encoding the host part of a URI as intended by RFC7252 - which is potentially confusing.  Appendix A of I-D.ietf- core-resource-directory shows an example registration of an application group into a Resource Directory (RD), along with the CoAP group it uses and the resources supported by the application group. In this example an application group identifier is not explicitly encoded in the RD nor in CoAP requests made to the group, but it implicitly follows from the CoAP group used for the request.  So there is a one-to-one binding between the CoAP group and the application group.  The "NoSec" security group is used. A best practice for encoding application group into a Group URI is to use one URI path component to identify the application group and use the following URI paths component(s) to identify the resource within this application group.  For example, /<groupname>/res1 or /base/<groupname>/res1/res2 conform to this practice.  An application group identifier (like <groupname>) should be as short as possible when used in constrained networks. </del> <ins> types of identifiers, such as name string, number, URI or other type of string.  An application group name may be explicitly encoded in a CoAP Group URI, or it may be not included in the Group URI.  This is an implementation-specific decision.  If the application group name is explicitly encoded in a CoAP Group URI, it can be encoded within one of the URI path component: this is the most common and RECOMMENDED method to encode the application group name.  A best practice for encoding application group into a Group URI is to use one URI path component to identify the application group and use the following URI paths component(s) to identify the resource within this application group.  For example, /<groupname>/res1 or /base/<groupname>/res1/res2 conform to this practice.  An application group name (like <groupname>) should be as short as possible when used in constrained networks. URI query component: using this method, the query may consist of the group name (?<groupname>) or it may be one parameter of the query (?g=<groupname> or ?param1=value1&gn=<groupname>). URI host subcomponent: using this method, the application group becomes equal to the CoAP group.  This can only be used if there is a one-to-one mapping between CoAP groups and application groups. URI port subcomponent: using this method, the application group is identified by a number that is encoded in some way in the destination port. There are also methods to encode the application group name within the CoAP request even though it is not encoded within the Group URI. Examples of such methods are: encode in a Uri-Host Option RFC7252 which is added to the CoAP request by the client before sending it out.  Each CoAP server that is part of the CoAP group, receiving this request, decodes the Uri-Host Option and treats it as an application group name. (It can also treat the application group name in this Option as a "virtual CoAP server" specific to that application group, exactly in the same way that the Uri-Host Option was intended to allow support for multiple virtual servers hosted on the same port.  The net effect of both treatments is the same.) encode in a new (custom/application-specific) CoAP Option which is added to the CoAP request by the client before sending it out. Each CoAP server that is part of the CoAP group, receiving this request, would by design understand this Option, would decode it, and treat it as an application group name. Finally, it is possible to not encode the application group name at all within the CoAP request.  This yields the most compact representation on the wire.  In this case, each CoAP server needs to determine the application group based on contextual information, such as client identity and/or target resource.  For example, each application group on a server could have a unique set of resources that does not overlap with any resources of other application groups. Appendix A of I-D.ietf-core-resource-directory shows an example registration of an application group into a Resource Directory (RD), along with the CoAP group it uses and the resources supported by the application group.  In this example an application group name "lights" is encoded in the "ep" (endpoint) attribute of the RD registration entry.  The CoAP group is ff35:30:2001:db8:f1::8000:1 and the "NoSec" security group is used. </ins> A security group is identified by a stable and invariant string used as group name, which is generally not related with other kinds of


Question: This adds an XML example. The only question is whether we need a prefix for ietf-https-notif in the example.

6. <del> Encoding notifications for the HTTPS notifications is the same as the encoding notifications as defined in RFC8040 Section 6.4, with the following changes.  Instead of saying that for JSON-encoding purposes, the module name for "notification" element will be "ietf- restconf, it will say that for JSON-encoding purposes, the module name for "notification" element will be "ietf-https-notif". With those changes, the SSE event notification encoded JSON example that would be sent over the HTTPS notif transport would appear as follows: </del> <ins> Notifications are encoded as defined in RFC8040 Section 6.4.  The examples in that section apply for sending notifications over the "https-notif" based transport. An example of YANG-Push in JSON would look something like this: An example of YANG-Push in XML would look something like this: </ins> 7.


Question:
Issue
NAME NAME pl review re issue
Looks good
the examples of errors use a pattern of using a link in a header, and then (supposedly) using a human-readable error message. what about using RFC 7807 instead and using examples that use problem reports to indicate failure semantics in addition to the status code?
I agree. coming up in the next draft.
NAME should we close this issue if it is resolved?
NAME closing this issue. Let me know if not addressed with my latest PR.

If the "Idempotency-Key" request header is missing for a documented idempotent operation requiring this header, the resource server SHOULD reply with an HTTP "400" status code with body containing a <del> link pointing to relevant documentation.  Alternately, using the HTTP header "Link", the client can be informed about the error as shown below. </del> <ins> link pointing to relevant documentation.  Following examples shows an error response describing the problem using RFC7807. Alternately, using the HTTP header "Link", the client can be informed about the error as shown below. </ins> If there is an attempt to reuse an idempotency key with a different request payload, the resource server SHOULD reply with a HTTP "422" status code with body containing a link pointing to relevant documentation.  The status code "422" is defined in Section 11.2 of <del> RFC4918.  The server can also inform the client by using the HTTP header "Link" as shown below. </del> <ins> RFC4918. The server can also inform the client by using the HTTP header "Link" as shown below. </ins> If the request is retried, while the original request is still being processed, the resource server SHOULD reply with an HTTP "409" status <del> code with body containing a link or the HTTP header "Link" pointing to the relevant documentation. </del> <ins> code with body containing problem description. Or, alternately using the HTTP header "Link" pointing to the relevant documentation </ins> Error scenarios above describe the status of failed idempotent requests after the resource server prcocesses them.  Clients MUST