ActionController::HttpAuthentication::Digest method: opaque

[sivsushruth]

https://github.com/rails/rails/blob/master/actionpack/lib/action_controller/metal/http_authentication.rb#L317

      # Opaque based on random generation - but changing each request?
      def opaque(secret_key)
        ::Digest::MD5.hexdigest(secret_key)
      end

This comment seems a bit nonsensical. Could someone who knows what the HTTP Digest Auth code is doing please either update the comment or remove it entirely.

Thanks