2016 saw a substantial rise in ransomware attacks and in some cases the return of some favourites with Cryptowall, CTB-LOCKER and TeslaCrypt being some of the most popular. The volume of attacks was in fact pretty steady for a good part of the year, with regular campaigns coming out on a weekly basis. It was interesting to see the variety in mechanisms used for the ransomware which not only included self-contained binaries but went all the way to the use of scripts. As part of the research I conducted last year, I wanted to understand why there's such a drive and lure for ransomware, outside of the victims payment, as well as have some way of properly testing "anti-ransomware" solutions with an unknown variant. So to do that, I went ahead and built my own ransomware and drew some conclusions on why it became so popular. This talk explore the background and process used to build a live ransomware that I was able to use for controlled testing. To finally draw some of my own personal conclusions.