[Openid-specs-ab] Comments on Aggregated Claims/Credential Provider documents

Sat Feb 6 04:25:46 UTC 2021

Tony,

Can you clarify, when you say JWK do you infact mean JWT?

Tobias

On Wed, 3 Feb 2021, 11:35 am nadalin--- via Openid-specs-ab, <
openid-specs-ab at lists.openid.net> wrote:

> So JWKs have a specific schema, its not the same schema ad JSON-LD, a goal
> of aggregated claims of different schemas may be problematic, so I’m not
> convinced that is a goal that we should undertake
>
>
>
> *From:* Openid-specs-ab <openid-specs-ab-bounces at lists.openid.net> *On
> Behalf Of *Kristina Yasuda via Openid-specs-ab
> *Sent:* Tuesday, February 2, 2021 3:41 AM
> *To:* Artifact Binding/Connect Working Group <
> openid-specs-ab at lists.openid.net>
> *Cc:* Kristina Yasuda <Kristina.Yasuda at microsoft.com>
> *Subject:* [Openid-specs-ab] Comments on Aggregated Claims/Credential
> Provider documents
>
>
>
> Hi,
>
> Below are comments/questions after reading Aggregated Claims
> <https://bitbucket.org/openid/connect/src/00140ab1e32c7160ed2635ce871c555ce7c32b75/openid-connect-claims-aggregation/openid-connect-claims-aggregation-1_0.md>
>  and Credential Provider
> <https://mattrglobal.github.io/oidc-client-bound-assertions-spec/#name-token-endpoint-response> drafts
> as requested during today's Connect call:
>
>
>
> Regarding core functionality of binding claims to the key material
> supplied by the Client, Aggregated Claims binds to `uid` - base64 url
> encoded representation of the thumbprint of the Client’s public key used
> for signing, while Credential Provider binds to `sub_jwk`- a raw key
> material that is a JSON object that is a valid JWK.
>
>
>
> Usage of `uid` seems to be a simpler approach. What would be an advantage
> of using `sub_jwk` over encoded thumbprint of a public key? Assuming one of
> the requirements of Credential Provider is to expand to the usage of
> additional credential formats, would usage of `uid` be applicable to
> JSON-LD too or does `sub_jwk` has an advantage?
>
>
>
> Credential Provider also defines a new scope `openid_credential`.
> Indicating in the request that binding is supported can be achieved through
> `credential_supported` OP metadata and could work without defining a new
> scope, like in Aggregated Claims document.
>
>
>
> In addition to a binding mechanism, Aggregated Claims defines a mechanism
> to request claims building up on `claims` parameter and Aggregated Claims
> mechanism of OIDC, and Credential Provider defines support for additional
> credential and identifier formats (such as JSON-LD, DIDs). These are not
> mutually exclusive and it should be possible to fulfill requirement of both
> in one document, while staying true to the scope of defining mechanism for
> claims/credential binding (and of course semantics would have to align!).
>
>
>
> Best Regards,
>
> Kristina
>
>
> ------------------------------
>
> *差出人**:* Openid-specs-ab <openid-specs-ab-bounces at lists.openid.net> が
> Takahiko Kawasaki via Openid-specs-ab <openid-specs-ab at lists.openid.net>
> の代理で送信
> *送信日時**:* 2020年11月17日 6:09
> *宛先**:* Artifact Binding/Connect Working Group <
> openid-specs-ab at lists.openid.net>
> *CC:* Takahiko Kawasaki <taka at authlete.com>
> *件名**:* [Openid-specs-ab] Feedback to OpenID Connect Claims Aggregation
> 1.0
>
>
>
> Hello,
>
> This is the first feedback from me to "OpenID Connect Claims Aggregation
> 1.0" as requested in the last AB/Connect WG call on Nov 9.
>
>
> - - - - - - - - - -
>
> - Section 5.3: I'm not sure RS256 is appropriate as the default value for
> claims_signed_response_alg. FAPI Part 2 Section 8.6 explicitly prohibits
> the algorithm for security reasons.
>
> - Section 5.4.2: Without diagrams and examples, it is difficult for me to
> understand how "uid" and "cp_sub" are used for what reasons.
>
> - Section 5.6.1: Why is it necessary to define "uid" request parameter? It
> seems that the "uid" request parameter would make it possible to get
> information about an arbitrary end-user who is different from the
> legitimate one that is associated with the presented access token.
>
> - Section 5.6.1: Why is it necessary to list "additional" client
> identifiers in "aud"? It seems that the "aud" request parameter would make
> it possible to add arbitrary client identifiers in addition to the
> legitimate one that is associated with the presented access token. It seems
> the description was added intentionally, but I'm not sure it's safe from a
> security perspective.
>
> - "uid": In Section 5.4.2, "uid" is the thumbprint of a public key. On the
> other hand, in Section 5.6.1, "uid" is an end-user's identifier. Using the
> same parameter name with different meanings is confusing.
>
> - Section 5.6.2: The 6th paragraph ("If the Aggregation Response is signed
> and/or encrypted...") contradicts with other parts in the specification
> itself. The specification requires that responses from Claims Endpoint
> always be signed and optionally encrypted.
>
> Editorial Issues
> - "http" is used in some links.
> - Link to RFC 7636 is wrong.
> - Links to JW* specifications are old. They should point to IETF RFCs.
> - Link to MTLS is old. It should point to the IETF RFC 8705.
> - Referenced OpenID.IDA specification is not the latest one. The published
> latest version is ID2.
> - The list in Section 1 is not properly formatted in HTML.
> - Parameter names should be monospace instead of italic.
> - Section 5.4: s/Code Authorization Flow/Authorization Code Flow/
> - Section 5.6.1: JSON object given to "aud" in the Aggregation Request is
> wrong.
> - Section 5.6.2: s/MAY elect to/MAY select to/
> - More diagrams and examples are needed for readers.
>
> To be honest, I couldn't understand the specification well due to its
> complexity and lack of diagrams and examples. What is the essential
> difference between UserInfo Endpoint and Claims Endpoint?
>
> Best Regards,
> Takahiko Kawasaki
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>

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