Avi Rubin also a pretty well known computer security researcher, a pretty big name in voting security, and the founder of ISE (Independent Security Experts).
Also of note, at JHU, an "intersession course" is a kind of mini-semester taking place late december-early january (hence intersession, between fall and spring). you may take one or take a break as you please. if you take the course, usually they are cute and interesting as we see here, and count for 1 credit.