14.1 and 14.2, due on November 14

1. (Difficult): Why doesn't Peggy want Victor to know which way she goes through the door? Didn't follow that in the opening door example.

I would like an example for 14.2.

Why is the second method in 14.2 faster than the first method?

About Arthur, I'm not understanding the part about the probability of square roots mod p or q or n.

2. (Reflection): Do ATM's work this way?

So much cryptography just seems like puzzles. They are intriguing. Difficult sometimes, but intriguing.