* See https://macgirvin.com/wiki/mike/OpenWebAuth/Home
* Requests to this endpoint should be signed using HTTP Signatures
* using the 'Authorization: Signature' authentication method
* If the signature verifies a token is returned.
*
* This token may be exchanged for an authenticated cookie.
* See https://macgirvin.com/wiki/mike/OpenWebAuth/Home
* Requests to this endpoint should be signed using HTTP Signatures
* using the 'Authorization: Signature' authentication method
* If the signature verifies a token is returned.
*
* This token may be exchanged for an authenticated cookie.