Sadly, because the OpenID authentication request is not signed, the CK can't be authenticated, but as you pointed out, although the user may authorize the application, the CK secret is still required to fetch the credentials. The worst that could happen is that a user will authorize an impostor, but the impostor will not be able to retrieve the token.
That being said, in our case, the CK contains additional information besides the scope. Yahoo's OAuth Permissions screen contains a lot of rich information including the application's name, description, developer(s), images, authorization lifetimes, etc. Over time, new fields may be added to the approval page. While it might make sense for the application's scope to be passed in at authorization time, does it also make sense to define new parameters for all the other application specific metadata? The actual data that needs to be displayed on an approval page is very SP specific, and some SPs may have security/legal policies requiring that all metadata is manually reviewed, which makes it impossible for metadata to be passed in at runtime. So that's why SPs may need the CK in order to display the Approval page. Make sense? Allen Dirk Balfanz wrote: > > Need to know the CK for what? What purpose would hinting at the CK > serve (since it wouldn't prove ownership)? And don't say "scope" :-) > _______________________________________________ specs mailing list specs@openid.net http://openid.net/mailman/listinfo/specs
