Constructing Picard Curves with Complex Multiplication using the Chinese Remainder Theorem
Published in Thirteenth Algorithmic Number Theory Symposium (ANTS XIII) Proceedings, 2019
We give a new algorithm for constructing Picard curves over a finite field with a given endomorphism ring. This has important applications in cryptography since curves of genus 3 allow one to work over smaller fields than the elliptic curve case. For a sextic CM-field $K$ containing the cube roots of unity, we define and compute certain class polynomials modulo small primes and then use the Chinese remainder theorem to construct the class polynomials over the rationals. We also give some examples.
Recommended citation: Constructing Picard Curves with Complex Multiplication, with Kirsten Eisenträger, Thirteenth Algorithmic Number Theory Symposium (ANTS XIII) Proceedings, pages 21-36, 2019. https://msp.org/obs/2019/2/p02.xhtml