Turns out, the slides I was using in class were out-of-date, and I had fixed some bugs in them elsewhere. The PDF that’s online is now current. When you get to the Chaum-Pedersen proof slides, you’ll see I redid the “Fake C-P” version (starting at slide 23), which will hopefully make it more clear how you can create a fake Chaum-Pedersen proof. And if you don’t get that, it’s not really essential to this course. What I want you to take away from this all is the broad applicability of challenge-response-style protocols in computer security.