You should definitely take a look at the last
November's #RebootingWebOfTrust whitepapers at
https://github.com/WebOfTrustInfo/rebooting-the-web-of-trust/tree/master/final-documents
in particular DPKI.
There are also good topic papers from that event at
https://github.com/WebOfTrustInfo/rebooting-the-web-of-trust/tree/master/topics-and-advance-readings
We are having our next #RebootingWebOfTrust this Sat/Sun in NYC
http://www.WebOfTrust.info and the first new topic papers are beginning to
arrive at https://github.com/WebOfTrustInfo/ID2020DesignWorkshop/
-- Christopher Allen