Your identity provider is not an application: it is infrastructure
On Monday 24 August, at 03:38, a denial-of-service attack began against Norway's shared government digital platform. Ten public services went down and several had nothing wrong with them: the door everyone goes through had jammed. Digdir writes on its status page that <code>eSignering</code> was unavailable "because of the limitations in ID-porten", and also that the services were "stable with the limitations that have been put in place" — part of the outage was put there by the defenders. Why single sign-on is still the right call, what changes when the door becomes infrastructure, and the three questions that reclassify it.