The personal website for Wu "Cousin" Ka Lok (also known as Cosine, usin, …). This website contains blogs and write-ups to CTF challenges that I find interesting. I would also like to share the mathematics behind cryptography, and how the designed may be exploited for attacks. I also made some visualizations of (sometimes seemingly abstract) mathematical concepts.

## Fundamental Concepts Underlying Elliptic Curves (Level 2): Divisors and Pairings

Elliptic curve has a lot of nice structures attached to it. One of them is the idea of divisors. Using divisors, we can construct an example of a pairing, wh...

## Fundamental Concepts Underlying Elliptic Curves (Level 1): Projective Coordinates

Last time we mentioned the basic concepts of Elliptic curves. However, there were some lingering questions about the weird representation of points in sage b...

## Fundamental Concepts Underlying Elliptic Curves (Level 0): High-level Overview

Elliptic Curve is one of the biggest topic in mathematics, for example number theory and geometry, and is used to, for example, prove the famous Fermat’s Las...