the concept (from earlier documentation)  is based on DWN nodes that store the history of the identifiers. biggest problem is the size of the nodes and therefore the number of participating nodes will limited. i can not find the latest system requirements.
the original concept is developed when csuwildcat was working at Microsoft in decentralized identifiers. 

 you are thinking of ION, that is mostly now a abandoned, they made a new DID called did:dht based on https://Pkarr.org