Basic key exchange and public cipher (RSA, SSL, HTTPS)

·       how to setup a secret key between two parties. For now we only consider protocols secure against eavesdropping. This question motivates the main concepts of public key cryptography, but before we build public-key systems we need to take a brief detour and cover a few basic concepts from computational number theory.

·       We will start with algorithms dating back to antiquity (Euclid) and work our way up to Fermat, Euler, and Legendre.

·       We will also mention in passing a few useful concepts from 20th century math.

·       Next Lecture we will put our hard work from this Lecture to good use and construct several public key encryption systems.