I chose to link to the prefacing blog entry rather then directly to the PDF not just because it's a light and good entry but also because it references some other context and WEIS 2018, coming up on June 18th. Definitely check out at least the first few pages of the paper itself however, it's quite readable and the initial scenario framing wrt Nemo Dat Quod Non Habet rules, darknet stores and so forth is interesting and quick.