The proof-of-work definition that I used in describing how Bitcoin solved the Byzantine generals problem [1], when questioned by James A. Donald, derives from the SANS testing process, which I’d been going through in the USA. I had been involved with SANS training and conferences since 1997. Between then and the time I dropped off doing courses in 2015, I had gained over thirty certifications. The courses included two master’s degrees [2]. The areas of study covered information security, programming, and much more. I took all three of the GSE hands-on exams [3]. I did so while studying for a master’s degree in law, a ... (full story)