Jubjub Curve

This crate provides jubjub curve arithmetic and also supports fully no_std and parity-scale-codec.

This crate uses https://github.com/zkcrypto/jubjub algorithm designed by @str4d and @ebfull. We replace field and curve implementation with zero-crypto to make this compatible with Substrate.

Specification

The Jubjub curve is one of twisted edwards curve.

• Twisted Edwards Curve $$ ax^2 + y^2 = 1 + dx^2y^2 $$

• Addition Law $$ (x_3 = \frac{x_1y_1 + y_1x_1}{1 + dx_1x_1y_1y_1}, y_3 = \frac{y_1y_1 + ax_1x_1}{1 - dx_1x_1y_1y_1}) $$