Elliptic Curve Geometric Properties

This section describes two geometric properties of an elliptic curve: horizontal symmetry and 3 intersections or less with straight lines.

Elliptic curves have two important geometric properties:

1. An elliptic curve is symmetrical about the x-axis. If point P = (x,y) is on an elliptic curve, then -P = (x,-y) is also on the same elliptic curve. We can also say that an elliptic curve is horizontally symmetric.

Here is an example of two symmetrical points P and -P on an elliptic curve (source: slideplayer.com):

Elliptic Curve Symmetrical to X-Axis
Elliptic Curve Symmetrical to X-Axis

2. An elliptic curve will intersect with any straight line in at most 3 points. This property will be used to help defining an addition operation on an elliptic curve.

Here is an example of an elliptic curve intersecting with a straight line in 3 points (source: sysax.com):

Elliptic Curve Intersects with Straight Line
Elliptic Curve Intersects with Straight Line

Table of Contents

 About This Book

Geometric Introduction to Elliptic Curves

 What Is an Elliptic Curve?

Elliptic Curve Geometric Properties

 Addition Operation on an Elliptic Curve

 Prove of Elliptic Curve Addition Operation

 Same Point Addition on an Elliptic Curve

 Infinity Point on an Elliptic Curve

 Negation Operation on an Elliptic Curve

 Subtraction Operation on an Elliptic Curve

 Identity Element on an Elliptic Curve

 Commutativity of Elliptic Curve Operations

 Associativity of Elliptic Curve Operations

 Elliptic Curve Operation Summary

 Algebraic Introduction to Elliptic Curves

 Abelian Group and Elliptic Curves

 Discrete Logarithm Problem (DLP)

 Finite Fields

 Generators and Cyclic Subgroups

 Reduced Elliptic Curve Groups

 Elliptic Curve Subgroups

 tinyec - Python Library for ECC

 EC (Elliptic Curve) Key Pair

 ECDH (Elliptic Curve Diffie-Hellman) Key Exchange

 ECDSA (Elliptic Curve Digital Signature Algorithm)

 ECES (Elliptic Curve Encryption Scheme)

 EC Cryptography in Java

 Standard Elliptic Curves

 Terminology

 References

 Full Version in PDF/EPUB