16.2, due on November 28

The Interesting

I like that we are finally getting to learn about using these elliptic curves to factor because we've read about the method for ages. I do find it interesting that we are just pretending that n is prime, though, when we know that n is a product of two prime numbers (and is therefore composite and not prime.)

The adding of points in these elliptic curves are crazy. I can't believe that (1,2)+(4,3)=(4,2). 

The Challenging

I would love to see why adding two points together gives such non-intuitive results. I guess I'm not familiar enough with elliptic curves to know why this works the way it does. The book mentions that we can use methods like Baby Step, Giant Step and the Pohlig-Hellman attack can be used on elliptic discrete logarithm problems, but I don't really understand how these elliptic discrete logarithm problems work so I can't see how I would apply these methods.