Dear Professors Juels (http://www.arijuels.com/) and Shi (runting@gmail.com), and Ahmed Kosba  akosba@cs.umd.edu :    I've found a reference to your recent paper, http://www.initc3.org/publications.html.  "The Ring of Gyges: Using Smart Contracts for Crime."   Perhaps you are not aware, but 20 years ago (1995-6) I wrote an essay on a very similar subject.  I called it "Assassination Politics".  cryptome.org/ap.htm .                 Jim Bell