Completed Programming Bitcoin Chapter 2 - Elliptic Curves. First came across the topic briefly during undergrad, but did not really delve into it back then. This chapter gives a nice intuitive explanation for elliptic curve and mainly discusses how the addition operation works. Addition retains some of the properties we attribute to normal addition --- commutativity, associativity, invertibility. But the operation itself involves following the staight line through the two points being added to the third point at which the line intersects the elliptic curve, and then taking its vertical reflection. (The illustrations in the book do a better job of explaining.) The exercises in this chapter go over how to implement addition of points on an elliptic curve in Python. The next chapter will use the properties discussed in this chapter to build cryptographic structures.