# Isogeny Graphs in Cryptography

These lectures notes were written for the summer school on *Graph
Theory Meets Cryptography* in Würzburg, Germany, in July 2019.  Their
goal is to survey the mathematical background of isogeny-based
cryptography, a blossoming new field with applications to post-quantum
cryptography and blockchains.  They are by no means a reference text
on the theory of elliptic curves, nor on cryptography; readers are
encouraged to complement these notes with the references given in the
bibliography.