Page Comparison

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Requirements for the resource owner

The resource owner MUST be able to choose a different AM for each Host
(The resource owner MUST be able to choose a different AM for each protected resource)

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In this step the following needs to be achieved:

The Host needs to get an Access Token from the AM to later be able to verify Access Tokens from Requesters. Lets name them AM-Host Access Tokens or AH-AT for short.
The Resource Owner needs to define conditions the Requesters need to fulfill before access t the protected resource is granted. This can e.g. be "is from domain twitter.com". This is done in terms of claims the Requester must send. Claims are basically attributes it sends and which can be verified eventually by the AM.
The AM needs to know some details about the Host, e.g. the title and description. This is important as in communication with the Resource Owner it needs to tell it some details about the which protected resource the Requester actually wants access to. So maybe it even needs to be described on a resource by resource basis? The user might not really know much about "xyz wants access to method POST on http://someapi.com/mrtopf/")

The protocol involves some steps:

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The AM provides the following information in it's XRD:

the authorization endpoint URL for the Host to initiate an Access Token authorization (Host authorization endpoint)
the token endpoint URL for the Host to exchange the temporary token with the access token (Host Token endpoint)
the authorization endpoint URL for the Requester to initiate an Access Token authorization (Requester Authorization endpoint)
the token endpoint URL for the Requester to exchange the temporary token with the access token (Requester token endpoint)
(some endpoint for verifying access to protected resources. This will become clearer when thinking about Step 3)

(example XRD here)

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