You can query the API over HTTP without authentication. However, to manage your trustmap (using the add and remove methods) and / or to implicitly provide the authenticating user (i.e.: you) as the context of a query, you need to use remote key authentication.
We do not support authentication over HTTP. All authenticated requests must be made over HTTPS.
To generate your remote key, go to Settings / Remote Key. Your key will be a string that looks something like:
191d9d6e0703ef429a9c53223e56b0e025a1b7b6eb25047f136e972b
To authenticate a request to the API, use the remote_key parameter. For example:
remote_key=191d9d6e0703ef429a9c53223e56b0e025a1b7b6eb25047f136e972b