This worksheet demonstrates an integer factorization method based on elliptic curves modulo n. I will present only a brief introduction to the theory of elliptic curves before writing the procedures for adding and multiplying points, finsihing with the general factorization algorithm. For a more thorough development of the ideas behind this method, I refer the reader to the excellent book; A Course in Number Theory and Cryptography , by Neal Koblitz. Please use this worksheet for good only. Do not use for evil.