Introduction to number theory lecture 18. Cryptography

This lecture is part of my Berkeley math 115 course "Introduction to number theory" For the other lectures in the course see https://www.youtube.com/playlist?list=PL8yHsr3EFj53L8sMbzIhhXSAOpuZ1Fov8 We give a brief introduction to the RSA method, an application of number theory to cryotography. The textbook is "An introduction to the theory of numbers" by Niven, Zuckerman, and Montgomery (5th edition).