Metadata declaring the historical keys endpoint location

[Michael Jones]

The historical keys endpoint is currently at <EntityIdentifier>/.well-known/openid-federation-historical-jwks. It would have been more consistent to publish its location in the Entity's metadata for the federation_entity Entity Type in a federation_historical_keys_endpoint property. I recommend that we do that.

Note that this need not be a breaking change to implementations in practice. If a deployment publishes a federation_historical_keys_endpoint metadata entry with the value <EntityIdentifier>/.well-known/openid-federation-historical-jwks, then clients locating the endpoint either the old way or the new way will continue to work.

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[Vladimir Dzhuvinov]

Another argument to make the historical JWKs URL a metadata parameter is that we shouldn’t be using a well-known URL for this unless absolutely necessary. This will make deploying federation easier too.

The current .well-known/openid-federation is enough to bootstrap the discovery and everything else, including the historical JWKs URL, can be found out from the Entity Configuration.

[Giuseppe De Marco]

@Michael Jones could you please create a PR for this?

[Michael Jones]

To be fixed by https://bitbucket.org/openid/connect/pull-requests/659

[Michael Jones]

Fixed by https://bitbucket.org/openid/connect/pull-requests/659